Percutaneous Treatment of Thrombosed Native Arteriovenous Dialysis Fistula Insufficiency: Efficacy of Mechanical Thrombectomy with Using the Stone Basket

PURPOSE: We wanted to evaluate the procedural success after percutaneous treatment of thrombosed native arteriovenous dialysis fistula insufficiency and the efficacy of performing mechanical thrombectomy with using the stone basket. MATERIALS AND METHODS: From March 2004 to June 2005, 36 thrombosed native hemodialysis access shunts in the upper limbs (brachiocephalic fistulas: 16 and radiocephalic fistulas: 20) were percutaneously treated in 30 patients. Declotting procedures were performed with using urokinase (100,000-200,000 unit) and manual catheter-directed thrombo-aspiration in all the patients. Angioplasty (6 mm in diameter and 4 cm in length) was performed at the identified area of the stenosis and/or with maceration of the thrombus. In 14 cases with massive thrombosis that was refractory to the above mentioned declotting procedures, mechanical thrombectomy with using a Wittich nitinol stone basket (Cook, Bloomington, IN) was performed. Data regarding the procedural success rate and the patency rate were analyzed by means of Fischer's exact test, and the Kaplan-Meier method with the Log-rank test was used for statistical inter-group comparisons between the brachiocephalic and radiocephalic fistulas. RESULTS: Successful declotting and restoration of thrill were achieved in 30 of 36 procedures (83%). Reestablishment of normal dialysis for at least one session was achieved in 29 of 36 procedures (81%). The procedural success rate for the brachiocephalic fistulas was 94% compared with 70% for the radiocephalic fistulas, but the difference was not statistically significant (p=0.104). In the cases with performing mechanical thrombectomy and using the stone basket, procedural success was achieved in 93% (13/14). The expected patency rates at 3, 6 and 12 months were 78%, 61% and 51%, respectively. The patency rates after declotting procedures were not significantly different between the brachiocephalic and radiocephlaic fistulas (p=0.871). CONCLUSION: Percutaneous treatment of thrombosed native arteriovenous dialysis fistula insufficiency showed an excellent success rate and patency rate, and especially performing mechanical thrombectomy with using the stone basket could increase the procedural success rate.

MR Findings of the Spinal Paraganglioma : Report of Three Cases

Extraadrenal paragangliomas involving the spine is less common and usually takes the form of intradural compression of the cauda equina. The authors report three cases of spinal paragangliomas resulting in extradural spinal cord compression and their MR findings. The MR imaging revealed a well-demarcated extradural mass with low to intermediate signal intensity on T1-weighted images and intermediate to high signal intensity on T2-weighted images compared to paravertebral muscles. After Gd-DTPA administration, heterogeneous and intense enhancement was found. Multiple punctate and serpiginous structures of signal void due to high-velocity flow were noted around and within the tumors on all sequences. In one case, the signal void structures were well corresponded with feeding arteries on angiography. These may be the characteristic findings of the extraadrenal paraganglioma involving the spine.

Endorectal MRI of Prostate Cancer: Comparison with Findings on Radical Prostatectomy

PURPOSE: To assess the accuracy of magnetic resonance (MR) imaging using an endorectal surface coil ineval-uation of local lesions of prostate carcinoma. MATERIALS AND METHODS: Twenty patients with surgically provenprostate carcinoma underwent MR imaging using a 1.5T unit and an endorectal surface coil made at the Asan MedicalCenter. T1-weighted images in the axial plane and T2-weighted images in the axial, coronal, and sagittal planeswere obtained in all patients. We divided the prostate gland into right and left lobe, then determined thelocation of carcinoma within it, as well as capsular penetration and seminal vesicle invasion. MR images werecompared with surgical specimens. RESULTS: MR imaging using an endorectal surface coil accurately demonstratedthe staging of prostate carcino-ma in 60% of patients (12/20), but with regard to the location of carcinoma withinthe prostate gland, capsular penetration, and seminal vesicle invasion, only nine cases (45%) showed completeagreement between en-dorectal surface coil MR images and pathologic findings. The accuracy of localizing thecarcinoma within the prostate gland, capsular penetration, and seminal vesicle invasion were 65%(13/20),70%(14/20), and 90%(18/20), respectively. CONCLUSION: MR imaging using an endorectal surface coil for thelocalization of prostate carcinoma and periprostatic tissue invasion showed a low degree of accuracy. Morespecific imaging findings are therefore needed.

Treatment of Radiation Induced Hemorrhagic Cystitis: Angiographic Embolization of Hypogastric Arteries / 대한비뇨기과학회지

PURPOSE: We assessed the long term efficacy and complications of angiographic embolization of hypogastric arteries in treating the intractable bladder hemorrhage induced by radiation. MATERIALS AND METHODS: From January 1990 to December 1997, a total of 43 patients with radiation induced hemorrhagic cystitis were evaluated. Of 43 patients, 5 patients were treated by bilateral selective angiographic embolization of the anterior branches of the hypogastric arteries. The embolic material used in all patients was gelfoam. RESULTS: Five patients with intractable bladder hemorrhage were treated by bilateral selective embolization of the anterior branches of the hypogastric arteries by gelfoam and successful in completely stopping or considerably decreasing intractable bladder hemorrhage in all patients. The average number of treatments was 1.6(range 1 to 2). There was no significant sequelae ocurred as a consequence of simultaneous bilateral occlusion of the hypogastric arteries. CONCLUSIONS: Radiation induced hemorrhagic cystitis that do not respond to irrigations with chemical cauterizing agents or transurethral fulguration of bleeding vessels can be successfully treated with bilateral selective angiographic embolization of the anterior branches of the hypogastric arteries.

MR Imaging Differentiation of Endometrial Cysts from Hemorrhagic Cysts

PURPOSE: To differentiate endometrial cysts from hemorrhagic cysts on the basis of MR findings MATERIALS AND METHODS: The MR findings of twelve patients with endometrial cysts(15 cases) and of nine patients withhemorrhagic cyst(12 cases) were retrospectively evaluated. Fourteen patients were surgically corfirmed and sevenwith hemorrhagic cysts were clinically diagnosed by resolution of the cysts during ultrasound follow up. Sixteenpatients underwent MR imaging using a 1.5T system(Magnetom Vision, Siemens, Germany), and for five patients a 2.0Tsystem(Spectro 2000, Goldstar, Korea) was used. MR images were retrospectively evaluated with respect to size andsignal intensity of the cyst, uni/multilocularity, shading, the hematocrit effect, clot.., fluid-fluid level andseptum, and thickness, signal intensity and enhancement of the cyst wall. RESULT: Eleven(73.3%) endometrial cystswere multilocular, but all hemorrhagic cysts were unilocular. The signal was hyperintense on both T1WI and T2WI inten(66.7%) endometrial cysts and seven(58.3%) hemorrhagic cysts. Shading was found in five(33.3%) and one(8.3%),respectively; the hematocrit effect in two(13.3%) and five(41.7%) respectively, clot in two of each type(13.3%,16.7%), and fluid-fluid level in only one hemorrhagic cyst. Septum was found only in endometrial cysts(five cases,33.3%); its signal intensity on both T1WI and T2WI was low, and on Gd-enhanced images was not enhanced. The cystwall was thick in five of each type(33.3%, 41.7%); its signal intensity was low on both T1WI and T2WI, and notenhanced on Gd-enhanced images. In eight hemorrhagic cysts, however, the cyst wall was iso to high in signalintensity on both T1WI & T2WI, and was enhanced on Gd-enhanced images. The prevalence of uni/ multilocularity,septum, and signal intensity and the presence of enhancement of the cyst wall were significantly different between the two groups(p< 0.005). CONCLUSION: Uni/ multilocularity, septum, and signal intensity and enhancement of thecyst wall were useful for the differentiation of endometrial from hemorrhagic cysts. Signal intensity of the cyst,shading, the hematocrit effect and clot were not helpful.

Differential Riagnosis of the Brain Tumor and Brain Abscess: the Usefulness of Dynamic MR Imaging

PURPOSE: To evaluate the usefulness of dynamic MR imaging in the differential diagnosis of intracranial tumorand abscess. MATERIALS AND METHODS: Dynamic MR images of 36 patients with surgically or clinically provenintracranial enhancing lesions were retrospectively reviewed. These lesions comprised 15 metastases, 14 gliomas,and seven abscesses. Images were sequentially obtained every 30 seconds for 3-5 minutes using the spin-echotechnique(TR/TE : 200 msec/15 msec) after bolus injection of gadolinium dimeglumine(2-3cc/sec). The dynamics ofcontrast enhancement of the lesions was analyzed visually and by calculating the sequential contrast-enhancementratio(CER). RESULTS: CER during the 30-second early dynamic phase was 93.16 in metastases, 67.78 in gliomas, and48.3 in abscesses(ANOVA, p<0.005). The contrast enhancement pattern of metastases showed rapidly increased signalintensity(SI) up to 30 seconds, followed by a relatively rapid decrease; less time was then required to reach theCER peak. In gliomas, SI increased gradually up to 180 seconds and then took a longer time to reach the CER peak.The SI of abscesses was similar to that of gliomas, with a more gradual increase for 30-60 seconds and a longertime for the CER peak to be reached. CONCLUSION: The contrast enhancement pattern and CER parameters seen ondynamic MRI can help differentiate intracranial tumor and abscess.

Verrucous Carcinoma of the Bladder Unassociated with Bilharzial Cystitis: A Case Report

Verrucous carcinoma that occurs only in the bladder is a very rare, well-differentiated squamous cell carcinoma. The tumor is a histologically and clinically distinctive variant of squamous cell carcinoma, and is almost exclusively associated with bilharzial infection. We report the radiologic findings of a case of verrucous carcinoma of the bladder unassociated with bilharzial infection.

Immature Teratoma of the Ovary: CT and US Findings

PURPOSE: To compare CT and US features of immature and mature teratomas of the ovary. MATERIALS AND METHODS: We retrospectively reviewed CT and US findings of 11 patients with immature teratoma and 18 patients(20 cases) with mature teratoma. The tumors were classified into three groups on the basis of image findings : predominantlycystic(type I), predominantly solid(type II), and mixed cystic and solid(type III). RESULT: All eleven cases of immature teratoma were of the mixed type(type III), showing multiple small(less than 2 cm) nodular and linear calcifications and fatty nodules within the solid component and adjacent to the septa of the cystic component of the masses. In contrast, mature teratomas were predominantly cystic in six cases, predominantly solid in eight,and mixed in six cases. In five of six mixed type mature teratomes, calcified fatty nodules were fewer and largerthan in immature teratomas. CONCLUSION: Immature teratoma may be diagnosed by the demonstration on CT or US ofmultiple small(less than 2cm) nodular and linear calcifications and fatty nodules in the solid and cystic components of the tumor.

Percutaneous Drainage of Pelvic Fluid Collection

PURPOSE: To evaluate safe access route and success rate of percutaneous drainage of pelvic fluid collection. MATERIALS AND METHODS: The 35 percutaneous drainages of pelvic fluid collection under the CT and fiuorosocpic guidance were done in 32 patients. The anterior transabdominal approach was done in 20 patients, while the nine patients used the transgluteal approach through greater sciatic foramen. Three patients , who had septated or noncommunicating abscesses, underwent drainage using both approaches. The catheter was removed when the patient's symptom and laboratory data were improved or the amount of drainage and the size of fluid collection were markedly reduced. Success, partial success and failure were classified. RESULT: The causes of fluid collection were complication of intraabdominal operation in 27 patient. The diagnosis after drainage included abscess(21), Ioculated ascites(6), and hematoma(4). The 27 cases(30 procedure) were treated successfully and the mean duration of catheter insertion was 10 days. The partial successes were two cases(2 procedures), which had palliative purpose. Three cases(3 procedures) were failed, which were multiple Ioculated ascites of pancreatic origin(2) and recurrent abscess(I). The significant complication during the procedure or drainage was not noted. CONCLUSION: The percutaneous drainage .under CT and fluoroscopy was effective technique for the management of pelvic. fluid collection, using anterior transperitoneal and transgluteal route through greater sciatic foramen.

MR Imaging of Proximal Femur: Age-related Changes

PURPOSE: The purpose of this study is to illustrate MR patterns of signal intensity of proximal femur in normal subjects according to the age distribution. METHOD AND MATERIAL: Tl-weighted MR images of the proximal femur in 125 subjects, aged 13 days to 25 years, were retrospectively analyzed. Age distribution was classified to 4 groups;below 4 months, 5 months to 4 years, 5 years to 14 years, and 15 years to 25 years. RESULTS: By the age of 4 months, the non-ossified femoral epiphysis was seen as intermediate-signal-intensity cartilage. At 5 months-4 years, the ossified fernoral capital epiphysis was seen within intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow surrounded by a rim of low-signal-intensity cortical bone. At 5-14 years, the ossified femoral capital and greater trochanteric epiphysis were seen within the intermediate-signal-intensity cartilage and appeared as decreased or increased signal-intensity red or yellow marrow. At 15-25 years, the proximal metaphyseal marrow showed increased signal intensity. Four patterns of the metaphyseal marrow were recognized by Ricci et al. The frequency of pattern la progressively decreased with age. Pattern 2 and 3 were visible in the 15-25 years age group. CONCLUSION: An understanding of the spectrum of normal age-related change of the proximal femoral cartilage and marrow patterns serves as the foundation for interpretation of proximal femur pathologies.