Radiology MCQs

Gout

2011-09-23T14:54:00.002+01:00

Regarding Gout,

Involvement of axial skeleton is rare.
Radiological changes are seen in 1-2 years after first clinical symtpoms.
Joint space loss and periarticular osteopenia are commonly encountered.
Tophi typically intensely enhance following gadolinium.
On ultraound, 'double counter sign' is highly suggestive of gouty arthritis

Answers: T, F, F, T, T

Explanation:

1st MTPJ is the most common joint affected, followed by 1st IPJ and TMTJ. Lower limbs are more often affted than upper limbs. Feer, wrist and elbows are commonly affected. Axial skeleton is rarely affected.
It takes 5-10 years to develop the radiological changes after first clinical symtpoms.
Punched out periarticular erosion with overhanging margins are hallmark of gouty arthritis. The joint spaces are preserved till late stage. Periarticular osteopenia is not a feature of gout. In late stages, diffuse osteopenia may be seen.
Tophi show low-to-intermediate signal on T1 and t2, and intensely enhance following contrast.
'Double counter sign' is seen as a hyperechoic irregular rim over the articular cartilage, and is considered a speific feature of gout, and is believed to be secondary to MSU crystals on the cartilage.

Reference:
S. Dhanda, A re-look at an old disease: A multimodality review on gout, Clinical Radiology, Volume 66, Issue 10, October 2011, Pages 984-992

Sonography of scrotum

2008-06-09T15:48:00.000+01:00

Regarding ultrasound of scrotum,
1. Increased blood flow to the epididymis is the most sensitive sign of epididymitis
2. Epidermoid cysts have characteristic alternating hyper and hypoechoic bands
3. Epididymal papillary cystadenomas are associated with Osler-Rendu-Weber syndrome
4. Adenomotoid tumors are the most common spermatic cord tumours.
5. Adenomatoid tumours of the epididymis most often arise from the head.

Answers: F, T, F, F, F

Notes: Increased size of epididymis and/or scrotum is the most sensitive sign of epididymoorchitis on ultrasound. Epididymal papillary cystadenomas are associated with von Hippel Lindau syndrome. Adenomatoid tumors are the most common benign solid tumours of epididymis (most often arise from tail), and lipomas are the commenest spermatid cord tumours.

Reference: Stengel JW et al. Sonography of the scrotum: case based review. AJR June 2008. S35-S45

Hypoxic ischaemic brain injury

2008-03-26T13:23:00.000Z

In evaluation of hypoxic ischaemic brain injury,
1. Diffusion weighted images are more sensitive than MR spectroscopy in acute setting
2. Most of the germinal matrix haemorrhage occur within 24 hours of birth
3. Cerberal cortex is more often involved in hypoxic injuries than deep grey structures in neonates and pre-term babies
4. Normal appearance on diffusion weighted images by the end of first week of hypoxic insult indicates reversal of hypoxic insults
5. Germinal matrix haemorrhage extending into ventricles is graded as IV

Answers: F, T, F, F, F

Notes: Diffusion weighted images are more sensitive than T1 and T2 weighted images, but MR spectroscopy is more sensitive than diffusion weighted images. MRS shows increased lactate in the deep gray matter, parieto-occipital region, and watershed zones as early as 2-8 hours. Germinal matrix haemorrhage is more often seen in pre-term babies born weighing less than 2000g and majority of the bleeds occur within 24 hours of birth. Deep grey structures are more often involved than cerebral cortex in both neonates and pre-term babies. Thalami, anterior vermis and dorsal brainstem are more frequently involved in pre-term babies, where as in full term neonates basal ganglia are more often involved. Diffusion-weighted images, although sensitive in diagnosing hypoxic damage, but they often underestimate the extent of the injury. Diffusion-weighted images also tend to normalise by end of the 1st week, but do not imply reversal hypoxic insult (pseuonormalization). Germinal matrix haemorrhages are graded into: Gr1 – subependymal haemorrhage without or minimal intraventiruclar bleed; gr 2 – germinal matrix and intraventricular haemorrhage without ventricular dilatation; gr 3 – gr 2 + ventricular dilatation; gr 4 – periventricular parenchymal haemorrhagic infarct

Reference: Huang BY et al. Hypoxic-Ischemic Brain Injury: Imaging Findings from Birth to Adulthood. RadioGraphics 2008;28:417-439

Inguinal and Femoral Hernias

2008-03-19T11:44:00.000Z

Regarding Femoral and Inguinal Hernias,

1. The indirect inguinal hernia is seen lateral to the inferior epigastric artery
2. The direct inguinal hernia has more potential for obstruction then indirect hernia
3. It is possible to classify the inguinal hernia based on ultrasound
4. Femoral hernias are seen in the posterolateral quadrant, when two perpendicular lines are drawn along the lateral edge of the pubic tubercle on the axial slices.
5. Coronal reformations are very useful in diagnosing incidental femoral hernias

Answers: T, F, F, T, T

Notes: The indirect inguinal hernia is seen lateral to the inferior epigastric artery and the direct is seen medial to it. The indirect inguinal hernia is congenital (failure of closure of internal inguinal ring) and the direct is secondary to weakness in the Hesselbach triangle. The indirect inguinal hernia is more prone for complication such as obstruction. Multislice CT is useful in identifying the inferior epigastric artery and helps in differentiating direct from indirect inguinal hernia. Two perpendicular lines are drawn along the lateral edge of the pubic tubercle. Femoral hernias lie in the posterolateral quadrant and the inguinal in the anterior half. Indirect are more medial and the direct or more lateral. Coronal reformations demonstrate "Radiological femoral triangle" which is normally fat filled and useful in demonstrating incidental hernias.

Reference: Cherian PT and Parnell AP. Diagnosis and Classification of inguinal and femoral hernia on multisection spiral CT. Clinical Radiology (2008) 63: 184-192

Gestational Trophoblastic disease

2008-01-02T15:23:00.000Z

Regarding gestational trophoblastic disease (GTD),

1. Incomplete moles are more likely to undergo malignant change than the complete moles
2. GTD is almost always completely curable with preservation of fertility
3. Lymphnode involvement is a rare feature of choriocarcinoma
4. GTD usually shows low resistance blood flow
5. It is rare to have other metastasis in the absence of lung metastasis

Answers: F, T, T, T, T

Notes: GTD includes complete mole (46XX diploid), incomplete mole (triploid), invasive mole, choriocarcinoma and placental site trophoblastic tumour. 16% of complete and 0.5% of partial moles undergo malignant changes. Lymph node involvement in GTD raises a possibility of rare GTD, placental site trophoblastic tumor, as lymphnode involvement is rare in choriocarcinoma or invasive moles. Uterine volume has prognostic implications in GTD. The normal PI is more than 1.5 and in GTD, there is low resistance flow, leading to decrease in PI. PI indirectly measures tumor vascularity. With exception of vaginal metastasis, it is rare to have other metastsasis in the absence of lung metastasis. The lung metastasis are usually rounded, measuer up to 3 cm, rarely cavitate, can be miliary, may block pulmonary arteris and cause PE symptoms.

Reference: Allen SD et al. Radiology of gestational trophoblastic neoplasia. Clinical Radiology Volume 61, Issue 4, April 2006, Pages 301-313

Limbic encephalitis

2007-12-21T16:55:00.000Z

Regarding limbic encephalitis (LE),

1. Usually presents with long term memory impairment
2. MRI typically shows high signal on T2 and FLAI in the limbic region
3. The most common underlying malignancy is small cell lung cancer (SCLC)
4. PET is useful in diagnosing underlying occult malignancy

Answers: F, T, T, T,

Notes: LE usually presents with short term memory impairment, seizures, confusion and psychiatric symptoms. Brain stem may also be involved. LE can be paraneoplastic or non-paraneoplastic. SCLC is the most common cause; other causes include testicular cancer, ca breast, teratoma, HL, thymoma. Although LE can be idiopathic, underlying malignancy should be searched.

Reference:
Rutherford GC et al. Imaging in the investigation of paraneoplastic syndromes. Clinical Radiology Volume 62, Issue 11, November 2007, Pages 1021-1035

Jejunum

2007-12-21T09:23:00.000Z

Regarding jejunum,

1. Jejunal valvulae conniventes are more numerous than ileal ones
2. Jejunal valvulae conniventes are 1 mm thick
3. Jejunal valvulae conniventes are characteristically spiral shaped
4. Low density barium is widely used as oral contrast for the CT evaluation of the jejunum in the UK
5. Jejunum accounts for 40% of small bowel

Answers: T, F, F, F, T

Notes: Jejunal valvulae conniventes are more numerous than ileal ones, measure 2mm in thickness and are circular in appearance. Ileal ones measure 1 mm and are spiral in appearance. Water is commonly used as oral contrast in the UK.

Reference:
Hyland R et al. CT features of jejunal pathology.Clinical Radiology Volume 62, Issue 12, December 2007, Pages 1154-1162

Lymphoma

2007-11-22T00:14:00.000Z

Regarding lymphomas,

1. Mesenteric nodes are commonly involved in Hodgkin's lymphoma
2. Nodal extension is contiguous in HL
3. Extranodal disease is common in NHL
4. Testicular lymphoma is the most common testicular tumor in people aged over 60 years
5. Adrenals are common extranodal sites for lymphomatous involvement

Answers: F, T, T, T, F

Notes: Axial, peripheral and mesentric nodes are commonly involved in NHL and mesentric nodes are rarely involved in HL. Nodal extension may be non-contingious in NHL, usually contigious (more often single nodal group) in HL. Extranodal disease is rare in HL (4-5%), common in NHL (20-40%). Lymphomatous involvement of kidneys is usually bilateral and contiguous retroperitoneal extension is seen with renal lymphoma in 25% and should not be mistaken for RCC. Involvement of adrenal in is rare (only 4% of NHL). In up to 40%, testicular lymphoma is bilateral and multifocal and is most common testicular tumor in people over 60 years. Gastric lymphomas account for 3-5% of gastric malignancies and far less common than adenocarcinomas and GISTs.

References:
Liete NP et al. Cross-sectional Imaging of Extranodal Involvement in Abdominopelvic Lymphoproliferative Malignancies.RadioGraphics 2007;27:1613-1634

CNS complications in paediatric oncology

2007-11-13T17:35:00.000Z

Regarding CNS complications in paediatric oncology patients,

1. Intratumoral hemorrhage is most often seen with osteosarcoma metastases.
2. Children with Wilm's tumour are at high risk of reversible posterior encephalopathy.
3. L-Asparginase, which is used in treating ALL, is associated with sinus venous thrombosis.
4. Aspergillus is the most common lethal fungal infection.
5. The dissemination of tumore via CSG occurs more frequently in paediatric age than in adults.

Answers: T, T, T, T, T

Notes:
Sarcomas are most commonly associated with intratumoral bleed in brain and osteosarcoma is the most common sarcoma to matastasize to brain in paediatric age group. Reversible posterior encephalopathy is seen in children with elevated blood pressure (on steroids), Wilm's tumor and the children on Cyclosporin-A. L-Asperginase is associated with sinus venous thrombosis. Methotrexate is associated with reversible perventricular white matter signal abnormality. Aspergillus is the most common lethal fungal infection and usually appear as intermediate signal on T2 and PD sequences; they may not show enhancement, because of lack if inflammatory response.

Reference:
Chu WCW et al. Imaging findgins of paediatric oncology patients presenting with acute neurological symptoms. Clinical radiology (2003) 58:589-603

Tuberculosis

2007-09-16T21:23:00.000+01:00

Regarding tuberculosis,

1. Radiographic evidence of hilar lymphadenopathy is more common in adults than in children
2. Cavitation is hallmark of post-primary TB
3. In TB meningitis, abnormal meningeal enhancement is more often seen in the basal cisterns
4. In spinal TB, calcification of abscess is characteristic
5. Calcification is seen more than 50% of renal TB

Answers: F, T, T, T, T

Notes: Radiographic evidence of lymphadenopathy is more common in children (96%) than in adults (46%) and more often seen in the right hilar and right paratracheal location. Cavitation is hallmark of post-primary TB, where as lymphadenopathy is rare (5%). Calcification of abscess is highly specific of TB spine. In renal TB, calcification is seen in more than 50% and the other findings include calcyceal deformity and papillary necrosis.

Reference: Burrill J et al. Tuberculosis: A Radiologic Review. RadioGraphics 2007;27:1255-1273

Benign scrotal tumors

2007-09-12T01:23:00.000+01:00

Regarding benign scrotal tumors,

1. Alternating low and high echogenic rings are pathognomonic for epidermoid cyst
2. Leydig cell hyperplasia may be seen as multiple small areas of hyperechogenicities
3. Epididymal cystadenoma is the most common epididymal tumor
4. Epididymal cystadenomas are associated with Von-Hippel-Lindau syndrome
5. Scrotal pearls have a high association of seminomas

Answers: T, F, F, T, F

Notes: Onion peel appearance of a testicular mass is virtually diagnostic of a epidermoid cyst. Leydig cell hyperplasia may be seen as multiple small areas of hypoechogenicities. Adenomatoid tumor is the most common epididymal tumor. Scrotal pearls are fibrous pseudotumors and are not associated with increased risk of malignancy

Reference: Kim W et al. US–MR Imaging Correlation in Pathologic Conditions of the Scrotum. RadioGraphics 2007;27:1239-1253

Malignant testicular tumors

2007-09-12T00:59:00.000+01:00

Regarding malignant testicular tumors,

1. 95% of malignant testicular tumors are of germ cell origin
2. Seminomas more often demonstrate calcifications compared to non-seminomatous tumors
3. Seminomas typically show well defined high signal mass on T2WI
4. Intratesticular calcification may be secondary to spontaneous regression of germ cell tumors
5. MRI usually differentiate seminomas from non-seminomatous germ cell tumors

Answers: T, F, F, T, F

Notes: 95% of malignant testicular tumors are of germ cell origin, in which seminomas are the most common type. Non-seminomatous germ cell tumors more often demonstrate calcifications, hemorrhage, fibrosis and cystic changes compared to seminomas. Germ cell tumors usually are isointense on T1 and hypointense on T2WI and it is not possible to differentiate seminomas from non-seminomatous lesions. Germ cell tumors may undergo spontaneous regression and may be seen as hypoechoic area or calcification

Reference: Kim W et al. US–MR Imaging Correlation in Pathologic Conditions of the Scrotum. RadioGraphics 2007;27:1239-1253

Stress fractures

2007-09-06T20:09:00.000+01:00

Regarding stress fractures,

1. Plain radiographs eventually pick up to 90% of stress fractures
2. Bone scintigraphy is sensitive and specific method of diagnosing stress fractures
3. CT is less sensitive than bone scintigraphy is the early diagnosis of stress fracture
4. T1WI are most sensitive sequences in the diagnosis of early stress injury
5. Fracture line in stress fracture is typically oriented perpendicular to the cortex

Answers: F, F, T, F, T

Notes: Plain radiographs detect 15% of early fractures and eventually pick up to 50% of stress fractures. Bone scintigraphy is sensitive but not a specific method of diagnosing stress fractures as infection, necrosis and tumors can mimic stress fractures. Fluid sensitive sequences (STIR or fat-sat T2WI) are most sensitive MR sequences in early detetction of stress injuries and T1WI better demonstrate advanced fractures.

Reference: Datir AP et al. Stress-related bone injuries with emphasis on MRI.Clinical Radiology Volume 62 Pages 828-836

Hypothalamus

2007-08-10T00:44:00.000+01:00

Regarding hypothalamic lesions,

1. Craniopharyngioma are typically predominantly cystic in adults
2. Hypothalamic germinomas typically involve base of the infundibular stalk
3. Hypothalamic hamartomas usually show no change in size on long term follow-up
4. Hypothalamic-chiasmatic gliomas are strongly associated with NF-1
5. Dynamic MRI is helpful in differentiating LCH from germinoma

Answers: F, T, T, T, F

Notes:
Craniopharyngiomas (CP) have a bomodal presentation; the paediatric CPs are typically solid and cystic (adamantinomous type) and the adult CPs are perdominantly solid (papillary).
Hypothalamic germinomas present in childhood and teens; synchronous lesions in pineal region are seen in 10%; typically seen in the base of the infundibular stalk and show homogenous contrast enhancement.
Hypothalamic hamartomas usually present by 10-20 years, boys being more commonly affected; present with precoucious puberty or gelastic seizures; sesille ot pedunculated isointense lesionsin tuber cinerium; do not change in size and signal at long term follow-up.
Hypothalamic-chiasmatic gliomas are paediatric tumors (2-4 years) and up to 50% have a family history of NF-1.
On dynamic MRI, germinomas, LCH and hemangioblastomas show gradual increase in enhencement without washout; adenohypophysitis showssharp increase in curve with steep washout.

Reference:
Saleem SN et al. Lesions of the Hypothalamus: MR Imaging Diagnostic Features. RadioGraphics 2007;27:1087-1108

Sickle cell disease

2007-08-01T10:49:00.000+01:00

Regarding sickle cell disease,

1. Mandible is usually spared from marrow expansion
2. On MR, irregular peripheral marrow enhancement around a nonenhancing center is more suggestive of osteomyelitis than infarction
3. Extramedullary haemopoitic tissue is shown as low signal on T1WI and high signal on T2WI
4. Hand-foot syndrome commonly affects infants
5. Sickle cell dactylitis is usually secondary to salmonella species

Answers: F, T, F, T, F

Notes:
Facial bones are usually spared from marrow expansion. Gadolinium enhanced MR demonstrates irregular peripheral marrow enhancement around a nonenhancing center in osteomyelitis. Extramedullary haemopoitic tissue is shown as intermediate signal on both T1WI and T2WI. Hand foot syndrome (sickle cell dactylitis) commonly affects between 6months and 2 years and is infarction of small bones of hands and feet.

Reference:
Ejindu VC et al. Musculoskeletal Manifestations of Sickle Cell Disease. RadioGraphics 2007;27:1005-1021

Small bowel malignant neoplasms

2007-08-01T00:43:00.000+01:00

Regarding small bowel malignant lesions,

1. 60-70% of the small bowel symptomatic lesions are malignant
2. Adenocarcinomas are most commonly seen near ileocaecal junction
3. Most of the carinoids airse from the distal ileum
4. Carcinoids typically show avid contrast enhancement, desmoplastic reaction and calcification
5. Kaposi's sarcomas are typically seen as submucosal lesions in the jejunum or ileum

Answers: T, F, F, T, T

Notes:
Nearly 70% of symptomatic small bowel tumours are malignant. Adenocarcinomas are most commonly seen in the duodenum. 40% of small bowel tumours are carcinoids. One third of carcinoid arise from the small bowel (most common site is appendix - 50%). Carcinoids typically avidly enhance, show desmoplastic reaction and calcification. Bowel is affected in up to 40% of Kaposi's sarcoma.

Reference:
Ramchandran L et al. Multidetector row CT of small bowel tumours. Clinical Radiology. Volume 62. Pages 607-614

Small bowel tumours

2007-08-01T00:09:00.000+01:00

Regarding small bowel tumours,

1. Most of the bowel tumours arise from the small bowel
2. Small bowel tumours are most common in the duodenum
3. Gastrointestinal stromal tumours (GIST) have a strong association with Garner's syndrome
4. Most of the small bowel lipomas are found in the distal small bowel
5. Most of the symtomatic small bowel tumours are benign

Answers: F, T, F, T, F

Notes:
Although the small bowel accounts for 90% of bowel mucosal surface, small bowel tumours account for less than 5% of bowel tumours. Tumours aremost common in the duodenum, followed by jejunum, followed by ileum. GIST tumours have a strong association with NF-1. Most of the lipomas are found in the distal small bowel and usually present with intussusception or bleeding. 60-70% of the small bowel tumours are malignant.

Reference:
Ramchandran L et al. Multidetector row CT of small bowel tumours. Clinical Radiology. Volume 62. Pages 607-614

Fibrosing mediastinitis

2007-07-30T23:58:00.000+01:00

Regarding fibrosing mediastinitis,

1. Commonly produces compression of the mediastinal structures
2. Associated pleural or pulmonary changes are common
3. Associated with histoplasmosis
4. Diffuse type is more common than focal type
5. Focal type commonly calcifies

Answers: T, T, T, F, T

Notes:
Fibrosing mediastinitis is a rare condition causing excessive fibrous tissue deposition. The etiology is often unknown. About 90% have compression of the medastinal structures, the most common being compression of the SVC and/or pulmonary artery. About 67% have pleural or pulmonary changes. Localised fibrosing mediatinitis has been associated with histoplasmosis.

2 patterns are recognised: focal and diffuse. Focal pattern is seen in 82% and is frequently calcified (63%). Diffuse form is diffusely infiltrating, noncalcified mass.

References:
1. Devraj A et al. Clinical Radiology. Volume 62, Pages 781-786
2. Rossi S E et al. Fibrosing mediastinitis. Radiographics. 2001;21:737-757.)

Marfan's syndrome

2007-07-27T00:02:00.000+01:00

The following are true regarding Marfan's syndrome (MS):

1. It is autosomal dominant
2. The most common cause of death is secondary to cardiovascular complications
3. Pectus excavatum is commonly seen in Marfan's syndrome
4. Dural ectasia can be seen on the plain radiographs as widening of the interpedicular distance
5. Spontaneous pneumothorax is usually secondary to bullae

Answers: T, T, T, T, T

Notes:
MS is autosomal dominat disease with the gene located on chromosome 15. Aortic dissection, heart failure and vavular disease are the most common causes of death in more than 90%. The cardiovascular manifestations include annuloaortic ectasia, aortic aneurysm, aortic dissection, pulmonary arterial dilatation. Musculoskeletal menifestations include scoliosis, pectus excavatum, pectus carinatum, arachnodactyly, protrusio acetabuli. Dural ectasia may be seen as widened interpedicular distance. Pulmonary manifestations include interstitial lung disease, bullous emphysema, bronchial anomalies, bronchiectasis, spontaneous pneumothorax.

Reference:
Ha H I et al. Imaging of Marfan Syndrome: Multisystemic Manifestations. RadioGraphics 2007;27:989-1004

Sickle cell disease

2007-07-26T00:13:00.000+01:00

Regarding sickle cell disease,

1. The most common cause of death is stroke
2. Intracranial anuesysms associated with sickle cell disease are usually single
3. Moya moya is characterictic of sickle cell disease
4. "hair-on-end"appearance on the skull radiograph is characteristic feature of sickle cell disease
5. The most common cause of osteomyelitis is salmonella

Answers: F, F, F, F, T

Notes:
The most common cause of death in sickle cell disease (SCD) is pulmonary complications. Children with SCD are 100 times more risk for pneumonias. Acute chest syndrome is more lethal in adults than children. The most common complication in brain are stroke, ischemia and atrophy. 11% have stroke by the age of 20 years. Infarcts are common in children and haemorrhage in adults. Moyamoya is secondary to large vessel occlusion with telangiectactic colateral circulation and seen in SCD, tuberous sclerosis, neurofibromatosis, vasculitides, infection. Intracranial anuerysms associated with SCD are usually multiple (57%) and 30% are seen in posterior circulation.

"Hair-on-end" appearance is seen in any anaemia. SCD patients are prone for bone infarcts and osteomyelitis, especially from salmonella. Osteomyelitis most commonly affects diaphysis of long bones.

Reference:
Madani G et al. The radiological manifestations of sickle cell disease. Clinical Radiology. Volume 62, Pages 528-538

Melanoma

2006-10-30T23:10:00.000Z

Regarding imaging of melanoma,

Majority of the melanoma metastasis to brain are hyperdense on unenhanced CT scan
Melanoma metastasis in brain usually show high signal on both T1 and T2
Most of the intraocular melanomas are metastatic
Lung metastasis is relatively common
Most of the bone metastasis are osteolytic

Answers: T, F, F, T, T

Notes: Most of the melanoma metastasis to brain are multiple, occur at corticomedullary junction and 85% are hyperdense on unenhanced CT scan. Hemorrhage is found in nearly 20%. On MR, they are typically high signal on T1 and low on T2. Most of the intraocular melanomas are primary and ultrasound and MRI are used in the evaluation of the lesion. 40% of lung metastasis are multiple, 20% solitory, 7% adenopathy and 28% combination of these. Bone metastasis is also relatively common and seen in 23% of ocular melanomas. The most common site is spine and most are lytic.

Reference: Kalkman E et al. Melanoma. Clin Rad 59 (2004): 313-326

Pancreatic adenocarcinoma

2006-10-27T00:08:00.000+01:00

Regarding pancreatic adenocarcinoma, (***)

Cigarette smoking is thought to be a significant risk factor
Whipple's procedure, a radical surgery for pancreatic carcinoma, carries a risk of mortality of 20%
Overall 5 year survival rate is 20%
In approximately 80%, the carcinoma arises from the head
Carinomas arising from the head carry worse prognosis than those arising from the body or tail

Answers: T, F, F, T, F

Regarding resectability of pancreatic adenocarcinoma, (***)

Tumour size more than 3cm is likely to be unresectable
Peripancreatic lymphadenoapthy is absolute contraindication for surgery
The tumour is likely to be irresectible if the contiguity between tumour and major vessel is more than 50%
Vascular occlusion makes the tumour irresectible
Invasion of splenic vessels is absolute contraindication for surgery

Answers: T, F, T, T, F

Notes: Cigarette smoking is thought to account for 30% of deaths from pancreatic adenocarcinoma. Diabetes and chronic pancreatitis are also associated with increased risk of pancreatic adenocarcinoma. Whipple's procedure carries a risk of 5% mortality. The survival rate, including the ones undergone Whipple's, is not more than 5%. 80% of carcinomas arise from the head. The carconomas arising from body, tail and uncinate process carry worse prognosis than those arising from the head, because of late presentation.

Tumours more than 3cm are unlikely to be resectable. Peripancreatic lymphadenopathy is relative contraindication for surgery. Contuguity of 25-50% is equivocal for resectability, where as more than 50% makes it irresectable. Vascular encasement, occlusion or alterationin contour or caliber makes the tumour irresectable. Involvement of gastroduodenal, celiac or superior mesenteric artery is indicator of advanced disease, where as invasion of splenic vessels or spleen is not absolute contraindication for surgery.

Reference: Smith Sl et al. Imaging of pancreatic adenocarcinoma with emphasis on multidetector CT . Clinical Radiology 59 (January 2004): 26-38

Liver infections

2006-09-15T23:53:00.000+01:00

Regarding hepatic infections, (***)

Entameoba histolytica is the most common cause in the UK
Ascending cholangitis is the most common cause of pyogenic infection
'Wheel spoke sign' seen on ultrasound is highly suggestive of amoebic liver abscess
Imaging guided aspiration is contraindicated in hydatid cysts
Is known complication of hepatic chemoembolization

Answers: F, T, F, F, T

Notes: Entameoba histolytica is the most common cause in developing world, but in developed world, pyogenic is the most common cause. In pyogenic abscesses, the most common organism isolated in solitary absess is Klebsiella pneumoniae and in multiple abscess E.coli. The most common mode of spread of infection for pyogenic is ascending cholangitis; for amoebic portal; phlebitis and for fungal, hepatic artery. On ultrasound, the pyogenic abscesses are usually hypoechoic with poorly defined irregular wall and may show echogenic debris. The amoebic abscesses are typically hypoechoic with absence of significant wall. Various ultrasound signs have been described for hydatid cyst and include double contour thick wall (due to triple layer), snow storm sign (falling of sand after patient repositioning), water-lilly sign with floating membranes (detachment of endocyst) and wheel spoke sign (daughter cysts). Heptaic infection is known complications of chemoembolization and radiofrequency ablation

Reference: Doyle DJ et al. Imaging of hepatic infections. Clin Rad 61: 737-746

Neuroimaging in HIV/AIDS

2006-08-30T22:41:00.000+01:00

Regarding toxoplasma encephalitis in HIV/AIDS, (***)

Toxoplasma encephalitis is more common than HIV encephalitis
Toxoplasma is the most common opportunistic neuroinfection in AIDS
Toxoplasma encephalitis preodominantly involves periventricular white matter
The more the nodular or ring enhancement, the more is the CD count
On an unenhanced CT scan, the lesions are usually hypodense

Answers: F, T, F, T, F

Notes: HIV encephalitis accounts for up to 60% with AIDS, where as toxoplasma encephalitis accounts for approximately 30% of cases. Toxoplamosis, being the most common opportunistic neuroinfection, may result in necrotising encephalitis, predominantly involving the basal ganglia and thalami. On Unenhcened CT, the lesions are usually isodense to grey matter, but may be hyperdense due to hemorrhage and on contrast, usually show ring or nodular enhancement. Faint or absent enhancement is seen if the CD count is less than 50 and the enhancement increases with increase in the CD count.

Regarding neuroinfections in HIV/AIDS,

HIV encephalitis preferentially shows white matter changes in the centrum semiovale
CMV encephalitis usually involves brain stem and periventricular white matter
CMV encephalitis typically heals by periventricular calcifications
Cryptococcus usually causes ring enhancing lesions in the basal ganglia
PML (progressive multifocal leucoencephalopathy) typically shows mass effect and contrast enhancement

Answers: T, T, F, F, F

Notes: Demyelination and gliosis in HIV encephalitis affects deep white matter, preferentially involving the centrum semiovale. CMV cause meningoencephalitis with predominant involvement of periventricular white matter and brain stem, ventriculitis, infarcts, spinal cord, cranial nerves. CT may show diffuse white matter hypodensity and on contrast, may show ependymal, ring or nodular enhancement. Periventricular calcification is a sign of congenital CMV infection and not a feature of CMV infection in immunocompromised. Cryptococcus is the most common fungal infection in AIDS and typically causes meningitis. PML is caused by Gr B papovavirus and shows bilateral pathy white matter abnormality without mass effect or contrast enhancement.

Reference:Offiah et al. The imaging appearances of intracranial CNS infections in adult HIV and AIDS patients. Clinical Radiology (2006) 61: 393-401

Renal trauma

2006-08-13T14:44:00.000+01:00

Regarding blunt injury of the kidney,

Nearly 50% of renal injuries are treated surgically
Presence of hematuria is an idication of serioud renal injury
Absence of hematuria excludes renal injury
Cortical rim sign on CT scan suggests devascularization
Hypertension is a known late complication of renal trauma

Answers: F, F, F, T, T
Notes: About 95% of isolated renal injuries are minor and are managed conservatively. Hematuria is seen in 95% of renal injuries, but absence of hematuria does not exclude renal trauma. Hematuria may be absent in severe renal trauma (25% of renal artery thrombosis may not have hematuria). Hematuria with hypotension is associated with increased risk of significant renal injury; but there is poor correlation between severity of hematuria and severity of renal injury. Complete devascularization shows absent nephrogram or cortical rim nephrogram. Early complications include urinary extravasation and urinoma formation, delayed bleeding, infection of the urinoma, perinephric abscess, sepsis, arteriovenous fistula, pseudoaneurysm and hypertension. Late complications include hydronephrosis, hypertension, calculus formation and chronic pyelonephritis.
References:
1. Fanney DR et al.CT in the diagnosis of renal trauma. RadioGraphics 1990; 10: 29.S201-214
2. Kawashima A et al.Imaging of Renal Trauma: A Comprehensive Review. RadioGraphics 2001; 21: 57

Splenic trauma

2006-08-12T21:45:00.000+01:00

Regarding splenic injury,

Spleen is the most commonly injured abdominal organ in blunt trauma
40% of rib fractures are associated with splenic injuries
40% of splenic injuries are associated with rib fractures
Splenic lacerations are seen as an area of low attenuation on contrast enhanced CT scan
Most of the splenic injuries are managed surgically

Answers: T, F, T, T, F
Notes:
Spleen is the most commonly injured solid abdominal organ. Most often due to blunt trauma and often (30-60%) associated with other organ injuries. 25% of left renal injury and 20% of left rib fractures are associated with splenic injury. 40% of splenic lacerations are associated with rib fractures. 20% of splenic injuries occur during surgical procedures. Spontaneous rupture can occur in an abnormal spleen, like in infectious mononucleosus or malaria. Subcapsular hematoma is seen as cresentic/lentiform low attenuation. Parenchymal lacerations are seen as irregularly low attenuation areas. Fracture is seen as complete seperation. Disruption of the capsule causes intraperitoneal hemorrhage. Late complications include splenic pseudocyst.
Grading: Grade 1 – Minor subcapsular tear or haematoma, Grade 2 – Parenchymal injury not extending to the hilum, Grade 3 – Major parenchymal injury involving vessels and hilum, Grade 4 – Shattered spleen.
Management:Isolated grade 1 and 2 are suitable for conservative management. The patients with cardiovascular instability need surgery, which include repair, spleen conservation surgery (at least 20% of spleen is preserved) and splenectomy. Approximately 30% fail conservative management.
References:
Roberts JL et al. CT in abdominal and pelvic trauma. RadioGraphics 1993; 13: 735

Epidermoid cyst of the testis

2006-08-12T15:47:00.000+01:00

Regarding epidermoid cysts of the testis,

Epidermoid cysts are one of the common cysts of the testis
Epidermoid cysts are commonly associated infertility
Epidermoid cysts are commonly multiple
The ultrasonic appearances are characteristic for epidermoid cysts
On Gd administration, epidermoid cysts usually enhance

Answers: F, F, F, T, F
Notes: Epidermoid cyst is a rare benign lesion of the testis (1%–2% of testicular lesions). Commonly the patients present between 2nd and 4th decades. Most of the epidermoid cysts are single and unilateral. Multiple or bilateral cysts are associated with Gardner syndrome, Klinefelter syndrome and cryptorchid testes. They are filled with laminated cheesy material. The clinical management is controversial and recently, organ-preserving surgery has been favored over traditional orchidectomy.Most patients present with painless mass, but a few complain of pain or discomfort.
US may show an echogenic centre surrounded by a hypoechoic ring and hyperechogenic rim, causing 'bull’s-eye' or 'target' lesion; or alternating hypoechoic and hyperechoic concentric rings, causing 'onion skin appearance'. The lesions are not vascular.MR shows low signal peripheral rim on both T1- and T2-weighted images and a circumferential high signal zone surrounding a low-signal central zone, or alternating concentric rings of low and high signal on T1- and T2-weighted images. On contrast, there is no enhancement.The central echogenic center may represent keratin debris and the concentric layeers may represent lipid and water containing materials. The squamous cell capsule causes hyperechoic rim.
The 'onion ring' appearance is charecteristic for an epidermoid cyst, although not pathognomonic. Simple and tunica albuginea cysts are anechoic. Tumors, abscesses and chronic inflammatory processes may have capsule, but are likely to show hypervascularity. Neoplasms usually enhance on Gd-enhanced MR. Hemorrhage may have heterogenous appearance on ultrasound.
References:
1. Cho JH et al. Sonographic and MR Imaging Findings of Testicular Epidermoid Cysts. AJR 2002; 178:743-748
2. Loya AG et al. Epidermoid Cyst of the Testis: Radiologic-Pathologic Correlation. RadioGraphics 2004; 24: S243-S246.
3. Woodward PJ et al. From the Archives of the AFIP: Tumors and Tumorlike Lesions of the Testis: Radiologic-Pathologic Correlation. RadioGraphics 2002; 22: 189.

Angiomyolipoma of the kidneys

2006-07-12T19:03:00.000+01:00

Regarding Angiomyolipomas (AML),

AMLs associated with tuberous sclerosis are more common than sporadic ones
Females are more commonly affected than males in both sporadic type and in those with tuberous sclerosis
AMLs are associated with neurofibromatosis
The most common complication is malignant transformation
AMLs are not suitable for embolization

Answers:F, T, T, F, F
Notes: AMLs are benign hamratomas. Sporadic type is usually seen between 50 and 80 years, has a female preponderance and comprises 80% of AMLs. AMLs are commonly seen in tuberous sclerosis (wide range, 20-80%) and also has a female prediliction. AMLs are associated with neurofibromatosis and VHL syndrome. Retroperitoneal haemorrhage is the most common and life threatening complication. The larger the tumour, the greater is the risk of haemorhage; hence AMLs larger than 4 cm are usually treated and the rest are followed. Embolization is increasing used to treat hypervascular AMLs.
References:

Rimon U et al. Larger renal angiomyolipomas: DSA grading and presentation with bleeding. Clin Rad (2006) 61, 520-526
Dahnert W. Radiology review manual 5th edition. Lippincott Williams & Wilkins.

Menisci of the knee

2006-07-12T15:52:00.000+01:00

Regarding meniscal injuries of the knee,

Posterior horn of the medial meniscus is the most commonly injured meniscus
On MRI, the high signal within the menisci has to extend into both parts of articular surfaces to call it a tear
Bucket-handle tear is a type of radial tear
Bucket-handle tear is more common in the lateral meniscus
Meniscal cysts are most commonly associated with horizontal tears

Answers: T, F, F, F, T
Notes: Posterior horn of the medial meniscus is the most commonly injured part of the menisci. The intrasubstance signal change indicated meniscal degeneration. If the high signal reaches at least one articular surface, then it is called a tear (grade 3). Orthoscopically, the meniscal tears are classified as longitudinal, radial and oblique. The bucket-handle tear is a type of longitudinal tear and is 3 times more common in medial meniscus. The meniscal cysts are commonly associated with horizontal tears.
Reference: Click here

Traumatic diaphragmatic rupture

2006-07-12T00:54:00.000+01:00

Regarding traumtic diaphragmatic rupture (TDI),

TDIs most commonly occur after penetrating trauma
Left diaphragm is more commonly ruptured than the right
About 50% of TDI are diagnosed acutely
The most commonly herniated organ is spleen
'Dependent viscera sign' is a very sensitive CT sign in the diagnosis of TDI

Answers: F, T, F, F, T
Notes: TDIs commonly occur after blunt trauma as in RTA or fall. Because of the liver, the right hemidiaphragm is ruptured less common than the left. Only about 10% of TDIs are diagnosed in acute setting. Stomach is most commonly herniated organ (32%), followed by colon (27%). CT is investigation of choice even in the acute setting. 'Dependent viscera sign' on CT is very sensitive in the diagnosis of TDI. The bowel or abdominal viscera usually do not contact the ribs due to seperation by diaphragm; contact indicates diaphragmatic injury and is known as 'dependent viscera sign'. Sagittal reconstruction is most sensitive and specific in the diagnosis of TDI.
Reference:

posterolateral corner injury of knee

2006-07-11T21:13:00.000+01:00

Regarding posterolateral corner injuries of the knee,

Posterolateral corner injuries are more common than medial knee injuries
Arcuate fracture is a strong indicator of posterior cruciate ligament tear
Segond fracture is a strong indicator of posterior cruciate ligament tear
Popliteus myotendinous injury is usually associated with other posterolateral corner injuries
Lateral collateral ligament injury is a part of posterolateral corner injuries

Answers: F, T, F, T, T
Notes: Posterolateral corner injuries are less common than medial knee injuries, but more debilitating. The bone injuries include Segond fracture (indicator of ACL injury), Arcuate fracture (avulsion fracture of fibular head - indicator of PCL injury), anterior rim tibial plateau fracture (indicator of PCL injury) and Gerdy's tubercle avulsion fracture. Soft tissue injuries include lateral collateral ligament, biceps tendon, popliteus, lateral head of gastrocnemius, fabellofibular ligament, arcuate ligament and mid-third lateral capsular ligament.
Reference: Harish S et al. Imaging of the posterolateral corner of the knee. Clin Rad (2006) 61, 457-466

Endometrial carcinoma

2006-07-06T23:16:00.000+01:00

(1) Regarding the endometrial carcinoma,

In Europe, endometrial carcinoma is second most common gynaecological malignancy, following cervical carcinoma.
In the UK, most of the endometrial carcinomas present late
FIGO Staging is based on MRI the of the pelvis and CT scan of the abdomen.
Endometrial carcinoma accounts for approximately 10% of postmenopausal bleeding
The incidence of nodal metastasis is 3% with deep myometrial invasion (stage IC).

Answers: F, F, F, T, F
(2) Regarding endometrial carcinoma,

CT is more accurate than endovaginal ultrasound in the diagnosis of myometrial invasion.
Zonal uterine anatomy is best seen on the T1WI.
Endometrial carcinoma is typically of low signal on the T2WI.
Endometrial carcinoma is of high signal compared to cervical stroma on the T2WI.
Lung is the most common site of distant metastasis

Answers: F, F, T, T, T
Notes:
Endometrial carcinoma is the most common gynaecological malignancy, followed by cervical carcinoma. Most of them present early, 75-80% in stage I, and have a good prognosis. Endometrial carcinoma accounts for 7-14% of post menopausal bleeding. FIGO staging is surgical and pathological based as clinical staging is inaccurate. FIGO does not consider imaging in the staging. However, the role of MRI in the diagnosis of myometrial and cervical invasion is increasing recognised. The incidence of nodal involvement is 3% with stage IB and 40% with stage IC and MRI may play an important role in this. Lymphadenectomy is done for Grade I/II with more than 50% myometrial invasion and for all grade III disease. A large randomised ASTEC (A Study in the Treatment of Endometrial Cancer) is being carried out to address role of lymhadenectomy and post-operative radiotherapy.
Overall accuracy of MRI is 83-92% and endovaginal ultrasound (77%) is more accurate than CT(61-76%) in predicting the myometrial invasion. Zonal anatomy is best seen on the T2WI and endometrial carcinoma is typically of low signal on the T2WI and enhance more slowly than myometirum on the dynamic enhancement scan. Inner myometrium is brighter than outer myometrium on dynamic MRI and maximum contrast between the two occurs at 50s. Endometrial carcinoma is of high signal compared to cervical stroma on T2WI.
Reference: Barwick TD et al. Imaging of endometrial carcinoma. Clin Rad (2006) 61, 545-555

Central Neurocytoma

2006-07-05T11:33:00.000+01:00

Regarding central neurocytoma (CN),

CN are typically located within the fourth ventricle.
Light microscopic appearance is similar to meningioma.
Most of the CNs present after 60 years of age.
The attachment to the lateral wall of the lateral ventricle is charactersitic for CN.
Intratumoral calcification is rare.

Answers: F,F, F, F, F
Notes: CNs are typically located within the lateral ventricle with extension into the third ventricle. The light microscopic features are similar to oligodendroglioma (OD) and many CNs were diagnosed as ODs in the past; hence immunohistochemistry with synaptophysin should be done. Most of the CNs present between 20 and 40 years with no sex prevelance. Attachment to the spetum pellucidum is considered as characteristic for CN. CNs are typically low on T1, high on T2 with usually some enhancment. Intratumoral calcification is common, where as haemorrhage is rare. Differentials include choroid plexus paiplloma, astrocytoma, meningioma, ependymoma, subependymoma and oligodendroglioma.
Reference: Zhang et al. Central neurocytoma: clinical, pathological and neuroradiological findings. Clin Rad (2006): 61: 348-357 .

Bone tumours of Ribs

2006-07-05T11:17:00.000+01:00

Regarding the benign bone tumours of the ribs,

Enchondroma (EC) are the most common benging tumours of the ribs.
Fibdrous dysplasias (FD) are usually seen in the posterior or lateral aspects of the ribs.
MRI is very sensitive in diagnosing the non-calcified cartilage of enchondroma.
In osteochondromas (OC), cartilage cap of less than 10mm is highly suspicious for malignant transformation.
Aneurysmal bone cysts (ABC) are commonly seen in the anterior aspect of the ribs.

Answers: F, T, T, F, F
Notes: Fibrous dysplasia is the most common benign rib tumour, followed by enchondroma and osteochondroma. FD usually occurs in the posterior or lateral ribs, where as EC and OC occur anteriorly at the costochondral junctions. Hyaline cartilage is not calcified and is best seen on T2WI as a bright signal. Cartilage cap of more than 2 cm in adult and 3 cm in children is highly suspicious for malignant transformation in OC. ABCs are usually seen in the posterolateral aspect of the ribs.
Reference:

Hughes et al. Benign primary tumours of the ribs. Clin rad (2006): 61:314-322

Trophoblastic Disease

2006-07-05T09:06:00.000+01:00

Regarding imaging of the gestational trophoblastic neoplasia (GTN),

Partial hydatidiform moles are more premalignant than the complete hydatidiform moles.
GTNs are almost always curable.
In GTNs, the uterine artery pulsatility index (PI) has been shown to predict methotrexate resistance.
Metastases typically occur in the peritoneum.
Uterine artery embolization (UAE) has a proven therapeutic effect in the management of post GTN vascular malformations.

Answers: F, T, T, F, T
Notes:16% of the complete and 0.5% of the partial moles can transform into malignant forms, i.e., invasive mole, choriocarcinoma and placental site trophoblastic tumour (PSTT). GTN has excellent prognosis and are almost always curable with methotrxate or actinomycin-D. USG and MRI show 'cluster of grape' or 'sand storm' appearance. GTN shows low impedence, high velocities (low PI) in the arteries. The uterine artery PI is known to predict response to chemotherapy. With the exception of vaginal disease, it is rare to have other metastatic disease in the absence of lung disease. Liver metastasis is a marker of poor outcome. Up to 15% of GTNs develop vascular malformations and UAE has been used successfully to treat them. Hyperthyroidism is a rare complication of GTN.
Reference: Allen SD et al. Radiology of gestational trophoblastic neoplasia. Clin Rad 2006:61:301-313.

Types of knee injuries

2006-06-29T11:55:00.000+01:00

Regarding the injuries of the knee joint,

In pivot shift injury, the ACL is commonly injured.
Dashboard injury commonly results in the disruption of the ACL.
In lateral patellar dislocation, the oedema is seen in the inferolateral patella and the anterior aspect of the lateral femoral condyle.
In lateral patellar dislocation, the lateral patello-femoral ligament may be injured.
'Kissing contusions' on the anterior aspects of the femur and tibia are seen in hyperextension injury.

Answers: T, F, F, F, T
Notes: Pivot shift injury is a non-contact, vulgus injury with femoral internal rotation commonly seen in skiers and Rugby players and the ACL is commonly disrupted. In dashboard injury, the knee is in 90° flexion with anterior force, leading to disruption of the taut PCL. In lateral patellar dislocation, the injury is on the inferomedial ascpect with injury to the inferomedial aspect of the patella, medial retinaculum, MPFL and medial patellotibial ligament. Hyperextension injuries are commonly seen in footballers, leading to kissing conutions, injury to ACL, PCL or menisci.
Reference: Timothy G. Sanders, Monica A. Medynski, John F. Feller, and Keith W. Lawhorn. Bone Contusion Patterns of the Knee at MR Imaging: Footprint of the Mechanism of Injury. RadioGraphics 2000; 20: 135.

Thalassaemia

2006-06-28T11:28:00.000+01:00

Regarding thalassaemia,

Skeletal changes are unusual before 6 months of age.
'Hair-on-end' skull appearance is characteristic for thalassaemia.
Ethoid air cells are usually absent.
Earliest changes are seen in the hand/feet bones.
MRI is sensitive in the early diagnosis of chelator toxicity in the skeleton

Answers: T, F, F, T, T
Notes: The skeletal changes in thalassaemia are unusual before 6 months of age and the first changes are usually seen in the hands and feet. 'Hair-on-end' appearance can be seen in any form of severe anaemia. Due to extra-medullary haemopoisis, the paranasal sinuses are not developed, except ethmoid air cells due to the absence of the red marrow around them. Iron chelation also causes changes in the skeleton, in the form of meta-epiphyseal dysplasia (one third of patients) and osteoporosis. Distal ulna is one of the earliest site to show dysplastic changes.
References:

Tyler PA et al. The radiological appearances in thalassaemia. Clin Rad 2006:61:40-52.
Dahnert W. Radiology review manual 5th edition. Lippincott williams and Wilkins 2003: 165-166

Venous Thromboembolism

2006-06-28T09:24:00.000+01:00

Regarding venous thromboembolic disease,

Deep venous thrombosis and pulmonary emboli can be diagnosed using MRI.
D-dimer assays have a high positive predictive value in suspected venous thromboembolic disease.
Duplex ultrasound is highly sensitive and specific investigation for symptomatic proximal leg deep venous thrombosis.
The more distal the leg venous thrombosis, the more risk for pulmonary embolism.
The dose of VQ (ventilation perfusion) scan is more than that for a CTPA (CT pulmonary angiogram).

Answers: T, F, T, F, F

Notes: DVT (Deep Venous Thrombosis) and PE (Pulmonary Embolism) are one of the major common challenges in day-to-day radiology practice. There are no common censuses or guidelines in the diagnosis and management of DVT or PE. D-dimer has a high negative predictive value, i.e. excluding DVT or PE, but it lackes positive predictive value. Duplex ultrasound remains investigation of choice in most of the hospitals to exclude or confirm DVT as this investigation is highly sensitive and specific (both >90%). VQ scan still remains a very common investigation in the diagnosis of PE and is based on PIOPED trail. Although conventional angiography is traditionally considered as a gold standard, CTPA is gaining wider acceptance in diagnosing PE, despite more dose than VQ scan. MRI is being tried in the diagnosis of PE and DVT by a technique (MRI-DTI, DTI= Direct Thrombus Imaging) which detects methhaemoglobin (M-Hb) and the initial results are promising.

Reference: Scarsbrook AF et al. Diagnosis of suspected venous thromboembolic disease in pregnancy. Clin Rad 2006: 61: 1-12.