Splenic Abscess

The CECT images above are from a patient who underwent sleeve gastrectomy (blue arrow) and experienced worsening abdominal pain in the weeks that followed. She was admitted with sepsis. There are necrotic areas within the spleen and multiple rim enhancing collections of air and fluid (red arrows) compatible with abscesses. Left upper quadrant fluid collections (sterile and infected) are a known complication of bariatric surgery.

REFERENCES

Blachar A and Federle MP. Gastrointestinal complications of Roux-en-Y gastric bypass surgery in patients who are morbidly obese: findings on radiography and CT. AJR Am J Roentgenol 2002;179:1437-42.

Yu J, Turner MA, Cho SR, et al. Normal anatomy and complications after gastric bypass surgery: helical CT findings. Radiology 2004;231:753-60.

Necrotizing Pancreatitis

Necrotizing pancreatitis is perhaps the most severe complication of acute pancreatitis because of the high associated mortality rate.  Bacterial contamination of pancreatic necrosis carries a 40-70% mortality rate, even after surgical debridement. Thus, early detection of necrosis is crucial in patient management. 

CECT will show lack of enhancement of the necrotic regions.  This finding is usually accompanied by other imaging indicators of pancreatitis such as infiltration of the peripancreatic fat planes. T2W MRI will show increased signal intensity of the necrotic regions while T1W post contrast images will show nonenhancing areas with decreased signal intensity. 

The above CECT images are from a young male admitted with acute pancreatitis whose clinical status was worsening. Lack of enhancement of the distal pancreatic body and tail are seen (red arrow)  consistent with necrosis. Note, the normal enhancement of the pancreatic head (blue arrow).

REFERENCES
Balthazar EJ. Acute pancreatitis: assessment of severity with clinical and CT evaluation. Radiology 2002;23:603-13.
O'Connor OJ, Buckley JM, Maher MM. Imaging of the complications of acute pancreatitis. AJR Am J Roentgenol 2011;197:W375-81.

To Stent or Not to Stent?

The above CECT axial images are part of a trauma work up in a young patient involved in an MVA with multiple abdominal injuries. Several liver lacerations are seen with subtle active extravasation of contrast. The third axial image shows a focal dissection at the origin of the celiac artery (red arrow). Sagittal reconstruction demonstrates absence of the celiac origin (the SMA origin is seen). Conventional angiogram shows a dissection at the origin of the celiac artery with opacification of its distal branches.

Typically, this dissection would be treated with a stent requiring short term anti-coagulation therapy (at least 6 months). However, a patient with multiple liver lacerations is not a candidate for anti-coagulation. Thus, despite injury to a major abdominal visceral artery, no intervention could be performed. The patient was monitored for hemodynamic stability and received several units of packed RBCs with no further drop in hematocrit.

Calvarial Metastases

Calvarial metastases tend to have aggressive features on MR imaging including ill defined margins, multiplicity, bony erosion/invasion, and seeding of the meninges. The most common primary malignancies to cause skull metastases are breast, lung, and prostate cancer.

The above T1W pre- and post contrast sagittal images demonstrate a large, lobulated calvarial lesion which enhances with contrast. This was found to be a metastatic focus in a patient with thyroid carcinoma.  


REFERENCES
Nemeth AJ, Henson JW, Mullins ME, et al. Improved detection of skull metastasis with diffusion-weighted MR imaging. AJNR Am J Neuroradiol 2007;28:1088-92.
Nguyen BD, McNaughton D. AJR teaching file: nuclear imaging of a tender skull mass. Am J Roentgenol 2007;189(6):S61-3.

Grade 1 Renal Injury

Axial image from a CECT obtained as part of a trauma work up demonstrates a crescentic collection inseparable from the right kidney, with mass effect on the renal parenchyma, containing regions of high attenuation. The right renal parenchyma enhances homogeneously. Findings are compatible with a subcapsular hematoma which falls under the spectrum of Grade 1 renal injuries, previously discussed here.

REFERENCES
Harris AC, Zwirewich CV, Lyburn ID, et al. CT findings in blunt renal trauma. Radiographics 2001;21:S201-14.

Osteochondritis Dissecans Revisited

Coronal and sagittal T1 and T2WI demonstrate curvilinear low signal intensity in the medial femoral condyle on T1WI with high signal on the corresponding T2WI. Findings are consistent with osteochondritis dissecans previously discussed here.

Iatrogenic Pneumocephalus

Axial NECT images from a female patient who presented with a headache 6 hours post partum demonstrate air outlining the anterior horns of the lateral ventricles. The patient received epidural anesthesia during labor which is the most likely cause of this imaging appearance.


REFERENCES
Zak IT, Dulai HS, Kish KK. Imaging of neurologic disorders associated with pregnancy and the post partum period. Radiographics 2007;27:95-108.