Inguinal and Femoral Hernias

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

Jejunum

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

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

Tuberculosis

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

Small bowel malignant neoplasms

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

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

Pancreatic adenocarcinoma

Regarding pancreatic adenocarcinoma, (***)

1. Cigarette smoking is thought to be a significant risk factor
2. Whipple's procedure, a radical surgery for pancreatic carcinoma, carries a risk of mortality of 20%
3. Overall 5 year survival rate is 20%
4. In approximately 80%, the carcinoma arises from the head
5. 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, (***)

1. Tumour size more than 3cm is likely to be unresectable
2. Peripancreatic lymphadenoapthy is absolute contraindication for surgery
3. The tumour is likely to be irresectible if the contiguity between tumour and major vessel is more than 50%
4. Vascular occlusion makes the tumour irresectible
5. 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

Regarding hepatic infections, (***)

1. Entameoba histolytica is the most common cause in the UK
2. Ascending cholangitis is the most common cause of pyogenic infection
3. 'Wheel spoke sign' seen on ultrasound is highly suggestive of amoebic liver abscess
4. Imaging guided aspiration is contraindicated in hydatid cysts
5. 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

Splenic trauma

Regarding splenic injury,

1. Spleen is the most commonly injured abdominal organ in blunt trauma
2. 40% of rib fractures are associated with splenic injuries
3. 40% of splenic injuries are associated with rib fractures
4. Splenic lacerations are seen as an area of low attenuation on contrast enhanced CT scan
5. 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

Traumatic diaphragmatic rupture

Regarding traumtic diaphragmatic rupture (TDI),

1. TDIs most commonly occur after penetrating trauma
2. Left diaphragm is more commonly ruptured than the right
3. About 50% of TDI are diagnosed acutely
4. The most commonly herniated organ is spleen
5. '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:

1. Eren S et al. Imaging of diaphragmatic rupture after trauma. Clin Rad (2006)61, 467-477
2. ABCs of blunt trauma