Ischemic Colitis

Findings and interpretation:

• There is branching, peripheral intrahepatic gas involving multiple segments of the liver (primarily left side) and extending to the peripheral margins. This indicates portal venous gas.
• The caecum is distended with mural thickening and surrounding fat stranding.
• There is gas in the bowel wall, indicating pneumatosis coli, as well as extraluminal foci of air, indicating perforation. There is gas in the lumen of a draining mesenteric vein adjacent to the caecum.
• Peri-colic fat stranding and mural thickening extends to the ascending colon, hepatic flexure and proximal segment of the transverse colon.
• There is extensive vascular mural calcification involving the abdominal aorta; the proximal SMA shows a filling defect occupying the entire lumen.
• There is wedge-shaped hypo-enhancement of a segment of renal parenchyma in the left kidney, indicating a renal infarct.

Incidental findings:

• Cardiomegaly with calcification of the left ventricular wall posteriorly, indicating prior myocardial infarction.

The findings represent ischemic colitis involving the proximal colon, caused by acute thrombo-embolic occlusion of the proximal SMA due to atherosclerotic vascular disease.

Principal diagnosis:

Ischemic colitis

Differential diagnosis:

• Infectious colitis (unlikely as this would not cause portal venous gas, and does not fit with the SMA occlusion)
• Diverticulitis (unlikely as there are no diverticula; again it does not fit with SMA occlusion)

Management:

• Immediately contact the referring physician and notify them of the findings.
• Emergency laparotomy is required in these cases.

Ileo-ileal intussusception caused by Meckel’s diverticulum

Findings and interpretation:

• There is a tubular structure in the pelvis with two layers of bowel wall, and mesenteric fat and vessels within. This structure appears continuous with the small bowel and represents telescoping of one segment of ileum into the other.
• There is fluid surrounding the intussuscepted loop of bowel.
• There is a blind ending tubular structure arising from the small bowel at the point where one segment of bowel enters the other. This represents a Meckel’s diverticulum.
• A few subcentimetric lymph nodes in the ileal mesentery are reactive

Pertinent negative findings:

• No portal venous gas.
• No extraluminal gas to suggest perforation.
• There is no dilatation of the small bowel proximal to this segment.

The findings represent an intussusception with the base of a Meckel’s diverticulum acting as a lead point. Fluid surrounding the intussuscepted loop of bowel is suggestive of ischaemia.  

Principal diagnosis:

Ileo-ileal intussusception caused by Meckel’s diverticulum.

Differential diagnosis:

Intussusception caused by a different lead point such as lymph nodes.

Management:

Urgently contact referring physician and inform of findings. This patient will require emergent laparotomy.

Findings and interpretation:

CT:

• There is fresh blood density indicating acute haemorrhage within the fourth ventricle, with a fluid-fluid level adjacent to it more cranially. This represents acute on chronic haemorrhage.
• The post-contrast images show peripheral rim enhancement around the haemorrhage.
• There is effacement of the fourth ventricle with resultant obstructive hydrocephalus.

MRI:

• There is a mass in the midline, arising from the roof of the fourth ventricle, with central high T1 and low T2 signal and a fluid-fluid level, indicating intratumoral haemorrhage.
• There is surrounding FLAIR hyperintensity. The mass shows avid rim enhancement.

The findings represent a posterior fossa, midline, haemorrhagic neoplasm.

Principal diagnosis:

Ependymoma (haemorrhage is more common in ependymomas than medulloblastomas)

Differential diagnosis:

• Medulloblastoma (although medulloblastomas typically arise from the roof of the ventricle, they rarely bleed)

Management:

Alert referring physician of diagnosis. Recommend neurosurgical consult for placement of ventricular CSF shunt.

Refer for discussion at neurosurgery MDT to discuss further imaging of the entire spine by MRI to search for drop metastases, as well as excisional biopsy.

Findings and interpretation:

Initial CT (portal venous phase):

• There are multiple, peripheral hypodense lesions in the liver parenchyma, some of which appear wedge shaped.
• The pancreas is edematous, with peripancreatic fluid and fat stranding.
• There is intense enhancement of the renal parenchyma in both kidneys.
• The spleen is hypo-enhancing.
• The small bowel loops in the right iliac fossa have thickened walls and show greater enhancement than normal.
• The IVC shows a ‘slit-like’ appearance.

Second CT (obtained 10 minutes later):

• There is persistent intense enhancement of the renal parenchyma.

The findings are abdominal sequelae of severe and prolonged systemic hypotension. There are hepatic infarcts, and a very prolonged nephrogram in the kidneys indicating acute tubular necrosis.

Principal diagnosis:

Hypoperfusion syndrome (shock abdomen)

Differential diagnosis:

None

Management:

Urgently contact referring physician and inform of findings.

Small Bowel Adenocarcinoma

Findings and interpretation:

• There is a soft tissue mass in the right iliac fossa, which is arising from a loop of ileum. The mass shows peripheral enhancement with a non-enhancing centre.
• There are large, peripherally enhancing lymph nodes in the small bowel mesentery with non-enhancing centres.
• The small bowel loops are uniformly dilated with multiple air-fluid levels visualised. The large colon is collapsed.
• There is a small amount of free fluid in the right paracolic gutter and perihepatic region.

MRI:

• The soft tissue is heterogeneously T2 hyperintense with a hypointense periphery.
• The enhancement pattern demonstrated on CT is again seen.

Pertinent negative findings:

• There are no liver lesions. No focal lesions in the visualised bones and lung bases.
• No extra-luminal air / evidence of bowel perforation.
• The pelvic organs, including both adnexae, are separate from the mass and are normal.

The findings represent a soft tissue neoplasm arising from the terminal ileum, with local lymph node spread. Non-enhancement of the centre indicates central necrosis, which implies a high grade malignancy. The mass is causing small bowel obstruction proximal to it.

Principal diagnosis:

Adenocarcinoma of the small bowel

Differential diagnosis:

• Lymphoma of the small bowel
• Gastro-intestinal stromal tumour

Management:

Alert referring physician of findings.

Refer for general surgery MDT to discuss staging CT thorax and image guided biopsy of the mass for tissue diagnosis.

Findings and interpretation:

• The left adnexa is enlarged with a large, thick walled, multi-loculated fluid collection extending into the abdomen. The walls show post contrast enhancement.
• The left fallopian tube is fluid filled and distended, with thick walls that also show post contrast enhancement.
• The right adnexa also contains a thick walled fluid collection.
• There is surrounding inflammatory fat stranding and pelvic free fluid extending up the paracolic gutters and into the perihepatic space.

Pertinent negative findings:

• There are no solid soft tissue masses in the adnexae.

Incidental findings:

• Bilateral simple renal cysts.
• Hypodense liver lesion in segment IVB; this requires imaging follow up / biopsy.

The findings represent an inflammatory process involving both adnexae with multi-loculated abscesses.

Principal diagnosis:

Pelvic inflammatory disease

Differential diagnosis:

• Ovarian neoplasm (does not cause pelvic inflammation, and is extremely unlikely as there are no solid soft tissue masses)

Management:

Alert referring physician of findings.

Recommend possible image guided or surgical drainage.