Materials and Methods: From February 1997 to February 1999, 83 renal MRA examinations were performed in the evaluation of patients with hypertension and declining renal function (Cr > 1.5). The incidence and grade of unilateral and bilateral renal artery stenosis were recorded on gadohnium-enhanced MRA and correlated with conventional angiograms. Additionally, an axial cine phase-contrast (CPC) MRA was performed on each patient, and the degree of decreased diastolic flow was correlated with the serum Cr level. The diastolic flow levels were also correlated with treatment and treatment outcomes. Results: The incidence of significant unilateral renal artery stenosis (RAS) was 33% (n = 27) and of bilateral RAS was 22% (n = 18). Decreased diastolic flow on the CPC MRA occurred in 30% (n = 24) of patients and correlated well with the level of declining renal function and in general was an indicator of poor response to therapy. Conclusion: Declining renal function and hypertension can be due to bilateral renal artery stenosis and/or diffuse small-vessel disease. Both of these conditions can be diagnosed with Gd-MRA or CPC-MRA. A small number of patients with impaired renal function have no evidence of renal artery stenosis or small-vessel disease and likely have essential HTN and glomerular disease. The ability of MRA to adequately categorize these patients can have important therapeutic implications.
P-14 C o m p u t e r Tutorial of Cervical A n a t o m y Fadi M. E1-Merhi, MD, Bridgeport Hospital, Bridgeport, CT, Gerard J. Muro, MD This is a quick and easy-to-use tutorial and reference tool created with the Visual Basic programming language to function in a Windows environment. It is designed to convey the complex cross-sectional anatomy of the cervical spine and spinal cord to physicians, residents, and students. The program utilizes several unique features that set it apart from books and other tutorials. One powerful feature of this program is the ability to highlight a structure of interest and maintain its identity while scrolling through contiguous cross-sectional images. For example, once chosen, the highlighted course of one of the motor or sensory tracts can be viewed as one scrolls through axial MR images of the cervical cord. This feature imparts a lasting understanding of complex motor and sensory pathways. Another very useful feature of this program is the ability to identify a structure on an image by clicking on it. When selected, the structure is highlighted, and its name is posted. The tutorial also includes a series of normal variants as well as illustrations. Other features include a quiz for self-examination and a list of references. P-15 Intraspinal Synovial Cysts: A Pictoral Exhibit of C a s e s and Diagnostic I m a g e s Vinay K. Gheyi, MD, Christiana Care Health System, Newark, DE, Raul N. Uppot, MD, Carlos Flores, MD, Yakov Royfman, MD. Rahul Gupta, MD Lumbar synovial cysts are extradural degenerative lesions of the spinal canal associated with symptoms of lower back pain and radiculopathy. These lesions usually have a characteristic posterolateral location and variable MR intensity pattern depending upon the contents of the cyst. The purpose of this exhibit is to identify intraspinal extradural synovial cysts as a cause of lumbar radiculopathy and to understand the variable intensity patterns of these cysts depending upon their contents.
P-16 Serial Brain Scintigraphy for t h e Diagnosis of Brain Death Jugesh I. Cheema, MD, Medical Center of Delaware/Christiana Health Care, Newark, DE. Raul N. Uppot, MD, Vidya Sagar, MD Purpose: Initial technetium-99m hexamethyl-propyleneamine oxime (Tc-99m-HMPAO) scintigraphy of the brain does not always help confirm brain death. This exhibit will demonstrate how serial Tc-99m-HMPAO scanning helps confirm brain death. Materials and Methods: A pictorial exhibit showing initial flow and static scans with focally preserved cerebral circulation and subsequent scans showing lack of cerebral flow and uptake, consistent with brain death, will be presented. These patients were injected with Tc-99m-HMPAO, and images were obtained using a portable gamma camera. When the diagnosis of brain death could not be confirmed, the scans were repeated in the same manner one to two days later. Results: Serial scans done 24 to 48 hours later show lack of cerebral flow and uptake, consistent with brain death. Conclusion: When focally preserved cerebral uptake exists on a scintigraphy study, serial scanning 24 to 48 hours later may help to make a diagnosis of brain death. P-17 Practical Considerations in T r a n s t h o r a c i c CT-guided N e e d l e Biopsy Norris E. Lai, MD, UCLA Medical Center, Los Angeles, CA, Robert D. Suh, MD Purpose: Demonstrate val-lOUStechniques used to increase the diagnostic yield and to decrease the complication rate of transthoracic biopsies under CT guidance. Demonstrate simple techniques used to treat pneumothorax during and immediately after procedure. Materials and Methods: Since 1996, specific cases were selected to illustrate methods which may be used to improve the safety and efficacy of transthoracic needle biopsies and the treatment of intraprocedural pneumothorax. Results: Various examples with corresponding images are used to demonstrate many of these techniques which can improve the diagnostic accuracy and decrease the complication rate of this procedure. These techniques include adjustments in patient positioning, CT scanning. the use of intravenous contrast, biopsy needle selection, needle access path, and saline injection into pleural and mediastinal spaces. Conclusion: CT-guided transthoracic needle biopsy is a wellestablished, accepted procedure used for the diagnostic evaluation of thoracic lesions. This has proven to be a sensitive technique used to assess lung carcinomas, other neoplasms, and bemgn processes. Various techniques may be used to improve the diagnostic sensitivity of the procedure, avoid potential pitfalls, and treat immediate complications such as pneumothorax. P-18 CT Evaluation for Lower Extremity Deep V e n o u s Thrombosis: Signs and Benefits Eddie G. Shell II, MD, Scott & White Memorial Hospital, Temple, TX, Michael L. Nipper, MD Purpose: To demonstrate the consistent CT signs produced by lower extremity deep venous thrombosis and advocate the usefulness of CT in certain patient populations.