Gadolinium-enhanced Excretory MR Urography: Comparison with MR Urography Using HASTE Technique

PURPOSE: To compare the feasibility of gadolinium-enhanced excretory MR urography(GEMRU) and conven-tional MR urography using the half-Fourier acquisition single-shot turbo spin-echo(HASTE) sequence in pa-tients with hydronephrosis or non-visualized kidney. MATERIALS AND METHODS: Fifteen patients with hydronephrosis or non-visualized kidney, as demonstrated by ul-trasonography or intravenous urography, were enrolled in this study. Nine were men and six were women, and their age ranged from 18 to 77 (mean, 60.6) years. For all MR examinations, a 1.5-T MR unit was employed. For breath-hold MR urography, the HASTE technique(MRU) was used, and reconstruction involved the use of a maximum intensity-projection (MIP) algorithm. For gadolinium-enhanced excretory MR urography, the fast low angle shot(FLASH) 3-D method was used and images were obtained at 5, 10, 20, and 30 minutes, and recon-struction again involved the use of an MIP algorithm. In some cases, additional GEMRU was obtained 24 hours after contrast material injection, and an MIP algorithm was used for reconstruction. MRU and GEMRU were independently interpreted by two radiologists who for quantitative analysis compared SNR with CNR, and at each anatomic level qualitatively analysed morphologic accuracy and diagnostic value of the lesions. RESULTS: In quantitative analysis, SNR and CNR differences between the two sequences at the renal pelvis and the level of the ureter were not significant (p>0.05). In qualitative analysis, GEMRU was superior to M-RU for the assessment of evaluated ureter at each level(p<0.05), anatomic anomaly and intrinsic tumor. Ureteral stones, however, were more easily diagnosed with MRU. CONCLUSION: For assessment of the ureter GEMRU is superior to MRU and has the advantage of evaluating renal function. We believe that for evaluation of the urinary tract, especially the distal ureter, GEMRU may be a valuable adjunct to routine MR urography.

A Study on the Activation of Supplementary Motor Area in Functional Magnetic Resonance Imaging of the Brain

PURPOSE: To evaluate the activated zone of the supplementary motor area through motor and sensorystimula-tion of both hands by fMRI. MATERIALS AND METHODS: Twenty-four healthy volunteers, ranging in age from 20to 30 years, served as sub-jects. They were divided into four groups and performed one of the four activationtasks : complex movement, fine movement, touch sensation, heat sensation. Complex movement consisted of a fingertask in which sub-jects flexed and extended all fingers repeatedly in union, without the fingers touching eachother(group I). Fine movement involved a thumb task in which subjects flexed and extended the thumb repeatedlywithout touch-ing the other fingers(group II). Touch sensation consisted of a palm task in which another personrepeatedly drew a circle on the subject 's palm (group III), and heat sensation involved of a palm task in whichsubject 's palm was touched by another person with a 40 degreeC water-bag (group IV). F-MRI was conducted on acommer-cial 1.5-T scanner equipped with echo-planar imaging. After overlapping images were obtained using aZ-s-core, and the mean/curve in the MR devices was evaluated, the activated zone of the supplementary motor RESULTS: Thirty-two of 48 images(20 of the 24 men) revealed activated zones in the supplementary motor area. Ingroup I, activation was observed in five subjects, in three of whom it was bilateral (contralateral activation).In group II, activation was observed in five subjects, in one of whom it was bilateral. In group III, activationoccurred in five subjects(bilateral in four, and contralateral in three), and In group IV, activation was alsoob-served in five ; in three of these it was bilateral. CONCLUSION: Using fMRI, and in association with motor andsensory tasks, the supplementary motor area was activated in 66.7% of healthy volunteers (32/48).

Experimental Study on the Appropriate Embolic Site During Superior Mesenteric Artery Embolization: Using Coiland Gelfoam

PURPOSE: To determine the effective embolic material and appropriate embolic site by comparing bowel changesafter arterial embolization in dogs in which the proximal or distal level of the superior mesenteric artery hadbeen occluded with gelfoam particles or a coil. MATERIAL AND METHODS: Using the coaxial catheter system,superselective arterial embolization was performed at sixteen sites in four dogs. In groups A and B, each site wasoccluded at the proximal or distal marginal artery, respectively, with gelfoam particles and in groups C and D, atthe proximal or distal artery, respectively, with a coi. All dogs were sacrifed one day after the procedure, andgross and microscopic histologic findings were evaluated. RESULT: In all dogs, the procedure was successful. Ingroup B, significant mucosal destruction, lymphocyte proliferation in submucosa and mucosa, and diffuse swellingin all layers of the intestine were found at all sites. The vessel in the submucosal layer was completelyobstructed by red blood cells and gelfoam.At three sites, the intestine showed diffuse ischemic change, and at oneother site, focal ischemic change was observed. In group D, exudation with destruction of mucosa and submucosalhemorrhage occurred at one site, but in groups A and C, intestinal layers were found to be normal. CONCLUSION: Using a coil, superselective arterial embolization was successful, even up to the distal level of the intestinalartery, and the intestine showed no ischemic change. Embolization with gelfoam must be performed carefully at theproximal level, and since it can cause severe intestinal necrosis, must be avoided at the distal level.

Fluoroscopically Guided Automated Gun Biopsy of Chest Lesions: Diagnostic Accuracy and Complications

PURPOSE: To determine the diagnostic accuracy and frequency of complications of fluoroscopy-guidedtransthoracic needle biopsy, using an automated gun biopsy system. MATERIALS AND METHODS: We retrospectively reviewed 86 patients who underwent automated gun biopsy between October 1995 and October 1996. An 18-gauge cutting needle was used in all cases. All biopsies were performed under fluoroscopic guidance by one interventional radiologist. RESULTS: Tissue sufficient for histologic diagnosis was obtained in 73 of 86 biopsies(84.9%). Fifty-six lesions were malignent and 30 were benign. Sensitivity and diagnostic accuracy for malignant lesions were 87.5% and 87.5%, respectively while cell type specificity in malignant diagnosis was 91.7%(11/12). Sensitivity and diagnostic accuracy for benign lesions were 80.0% and 73.3%, respectively. Postbioptic pneumothorax occurred in three of 86 biopsies(3.5%), one of which required placement of a chest tube. CONCLUSION: Automated gun biopsy is a simple, safe method for the diagnosis of focal chest lesions. An automated biopsy device offers high diagnostic accuracy in cases involving malignant and benign lesions of the chest, and is particularly useful for determining malignant cell type and specific diagnosis of benign lesions.