UPDATE:  I have it on reasonably good authority that our NUC MED department will be moved into a new area within the main department of radiology and that a GE Hawkeye SPECT/CT scanner will be installed in the new area.  To my knowledge this will be the first dedicated SPECT/CT in the region. This allows easy image registraton between SPECT and CT images and has applications in Oncology, Orthopedic, Neuro and Infectious Disease imaging.

Thoracic Aortic Pseudoaneurysms

Axial, Sagital and VR images. Post contrast CT Aorta. 

This patient had recent cardiac valve replacement at another hospital and presented to the ED with increasing chest pain.  There are 2 small pseudoaneurysms in the anterior ascending aorta possibly at the sites of prior canulation for cardiac bypass (red arrows).  There is hematoma in the anterior mediastinum (white arrow).

Update

Interview season for the residency program has ended.  Thank you to all of the candidates who came to Toledo for interviews. We had many excellent candidates this year and we now have to get to the business of ranking, which is always difficult. 

We are in the process of finishing a PACS upgrade and are in the final stages of a RIS upgrade.  This should really streamline workflow.

Renal Cell Carcinoma Invading Renal Vein and IVC (No not a PET/CT)

Select Image to Enlarge

Diffusion weighted coronal image and fused DWI and Axial T2w images show a large mass with restricted diffusion in the upper pole of the right kidney consistent with renal cell carcinoma invading the renal vein and the inferior vena cava.

Diffusion imaging offers an adjunct to traditional post contrast MRI.  High cellular density and abundant macromolecules in the cytosol cause the speed of diffusion of H2O in malignant tissues to slow.  This restriction of diffusion can be measured with MRI.

Cirrhosis, Hepatocellular Carcinoma and Portal Vein Thrombosis

Fig: Abnormal contour and size of liver consistant with cirrhosis.  Ascites.  Hepatocellular Carcinoma (red arrow) in segments 2, 3. Thrombus in the main Portal Vein extending into the Superior Mesenteric and Splenic Veins (white arrowhead) CLICK IMAGE FOR LARGER VIEW

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver. Most cases of HCC are secondary to either a viral  infection (hepatitis B or C) or cirrhosis (alcoholism is the most common cause of hepatic cirrhosis).

On CT, HCC can have three distinct patterns of growth:

1. A single large tumor
2. Multiple tumors
3. Poorly defined tumor with an infiltrative growth pattern

The usual outcome is poor, because only 10 - 20% of hepatocellular carcinomas can be removed completely using surgery. 

A new tyrosine kinase receptor inhibitor, sorafenib has been shown in a Spanish phase III clinical trial to add two months to the lifespan of late stage HCC patients with well preserved liver function.  Sorafenib is a small molecular inhibitor of several Tyrosine protein kinases. A protein kinase is a kinase enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). Phosphorylation usually results in a functional change of the target protein (substrate) by changing enzyme activity, cellular location, or association with other proteins. Tyrosine-specific protein kinases phosphorylate tyrosine amino acid residues, and like serine/threonine-specific kinases used in signal transduction. They act primarily as growth factor receptors and in downstream signaling from growth factors.  Sorafenib is unique in targeting the Raf/Mek/Erk pathway (MAP Kinase pathway). The MAPK/ERK pathway is a signal transduction pathway that couples intracellular responses to the binding of growth factors to cell surface receptors. This pathway is very complex and includes many protein component.

HCC presents radiographically as a spectrum, from large dominant hypervascular masses to diffuse, infiltrative, poorly visualized lesions.  Because of this imaging  for assessing treatment response in HCC with current modalities is challenging.  New imaging modalities for following HCC responses, especially to the new biologic therapies, must be developed.  Routine use of liver biopsy to conduct correlative studies is too risky . Diffusion weighted MR imaging may serve as an early biomarker of HCC response. Perfusion MRI is also being evaluated.

Thomas M, Zhu A (2005). "Hepatocellular carcinoma: the need for progress". J Clin Oncol 23 (13): 2892–9.

Diffusion-weighted MR imaging for determination of hepatocellular carcinoma response to yttrium-90 radioembolization. Deng J, Miller FH, Rhee TK, Sato KT, Mulcahy MF, Kulik LM, Salem R, Omary RA, Larson AC.  J Vasc Interv Radiol. 2006 Jul;17(7):1195-200.

CSF-OMA / CSF Pseudocyst

Sag CT and Oblique Sag VRCT show a ventriculoperitoneal shunt tube in the middle of a multilocular fluid collection in the lower abdomin and pelvis

CSF-oma ia s loculation of cerebrospinal fluid (CSF) at the distal end of the a ventriculoperitoneal shunt tube. It may occur secondary to adhesions. This results in an enlarging abdominal and/or pelvic mass at catheter tip, as CSF from the tip is no longer absorbed by peritoneum They can resolve spontaneously or after shunt revision and repositioning . Complications include infection and obstruction, the infection rate is 30% and can be higher in younger children.

Radiology of the Postoperative GI Tract, Bruce R. Javors, Ellen L. Wolf, Springer, 2003

Flexion Teardrop Fracture of C5

The flexion tear drop fracture is one of the most severe injuries of  the cervical spine. It is caused by extreme flexion of the cervical spine and often presents with loss of anterior column sensation and quadriplegia. The involved vertebral body is often displaced posteriorly  relative to the teardrop fragment which remains attached to the anterior longitudinal ligament. The facets may be subluxed, resulting in compression of  the spinal cord.


Kim KS, Chen HH, Russell EJ, Rogers LF: Flexion teardrop fracture of the cervical spine: radiographic characteristics AJR Am J Roentgenol. 1989 Feb;152(2):319-26.