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.

Causes of UPJ Obstruction

Congenital

• Abnormality of collagen muscle causing stenosis at the UPJ
• High ureteral insertion
• Aberrant crossing renal vessels: arteries/vein at the renal hilum crossing anterior or posterior to the ureter can cause obstruction
• Failure of recanalization of the ureter (considered less likely)
• Presence of valves/kinks (considered less likely)

Acquired

• Vesicoureteral reflux
• Stricture or stenosis secondary to trauma, recurrent infection, instrumentation, calculi
• Neoplasm: benign (polyp) or malignant (transitional cell, squamous cell)

REFERENCES
Lawler LP, Jarret TW, Corl FM, Fishman EK. Adult ureteropelvic junction obstruction: insights with three-dimensional multi-detector row CT. Radiographics 2005;25:121-34.

Focal Nodular Hyperplasia in the Caudate Lobe

Incidentally seen on a trauma CECT was a hyperdense with central low attenuation in the caudate lobe (first image). Further work up with MR re-identified the mass as isointense on T1WI, isointense with a hyperintense central scar on T2WI, and enhancement of the central scar on post contrast T1WI.  The findings are compatible with focal nodular hyperplasia.