Impact of unilateral common iliac vein occlusion on trapping efficacy of the Greenfield filter: an in vitro study.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the effect of unilateral common iliac vein occlusion on the capturing efficacy of the Greenfield filter in vitro. MATERIALS AND METHODS: A stainless steel over-the-wire Greenfield filter was placed in the Silastic inferior vena cava module of a pulsatile circuit. Three 30-mm blood clots in sets of five were injected through the module's right iliac limb with the circuit in four experimental conditions: vertical position, both iliac limbs patent (VP); vertical position, left iliac limb occluded (VOC); horizontal position, both iliac limbs patent (HP); and horizontal position, left iliac limb occluded (HOC). Each experiment was repeated 15 times, resulting in 75 clots per condition and a total of 300 clot introductions. RESULTS: Clot trapping efficacy was 36 of 75 (48%) for VP, 41 of 75 (55%) for VOC, 32 of 75 (43%) for HP, and 26 of 75 (35%) for HOC. Cross comparisons of the four conditions revealed a marginally significant difference (P = .0138 with a corrected test-wise alpha = .0125) only between horizontal and vertical positions with unilateral common iliac limb occlusion. CONCLUSION: Unilateral common iliac vein occlusion decreases the capturing efficacy of the Greenfield filter in the horizontal position in vitro. In patients with unilateral common iliac vein occlusion, use of inferior vena cava filters with higher capturing efficacy may be considered.

Radiographic determination of total lung capacity in patients with pneumonectomy.

To determine whether total lung capacity (TLC) can be measured from plain chest radiographs in patients with pneumonectomy, we examined 20 such patients (17 male, 3 female) who had pneumonectomy for lung carcinoma. In 16 patients the right lung was preserved, and in 4 the left. The TLC was measured with the helium dilution method and by planimetry of the anterior and lateral projections of the lung on chest radiographs, summing the anterior and lateral projected areas of the lung to a single value, S. The correlation between S and TLC by helium gas dilution was r = 0.95. Linear fit of TLC to S explained 99.5% of the variance in TLC, with the equation. The side resected did not influence the predictive value (p < 0.001). The interquartile range of the residual error was +/-130 ml, and standard error was 64 ml. Therefore in patients with pneumonectomy, TLC of the preserved lung may be estimated within +/-130 ml by planimetry of the anterior and lateral chest radiographs.

Percutaneous metallic self-expandable endoprostheses in biliary obstruction caused by metastatic cancer.

BACKGROUND/AIMS: Up to now, all reports about metallic stents concerned mostly patients with obstructive jaundice due to primary cancer although some of these series included a small number of patients with metastatic disease as a cause of occlusion of the bile ducts. The question of whether they should be used in patients with biliary obstruction due to metastatic disease, and consequently have a limited life expectancy, is investigated. PATIENTS AND METHODS: Between January 1994 and April 1995, we inserted percutaneously 20 metallic self-expandable endoprostheses in 14 patients with obstructive jaundice due to metastatic disease. RESULTS: Twelve patients died with a mean survival of 144.6 (range 25-338) days without any evidence of biliary reobstruction. For 2 patients, we have followup no longer than 30 days. Thirty day mortality was 7.2% (1/14). Jaundice reoccurred in one patient but wasn't related to stent obstruction, and he died during the first 30 days. We had 2 cases with moderate hemobilia. CONCLUSION: We believe that the use of metal stents in patients with obstructive jaundice due to metastatic disease is justified. Their high initial cost is offset by their prolong patency, decreased complication rate and shorter hospitalization.

Bronchopulmonary sequestration with MR angiographic evaluation. A case report.

Definitive diagnosis of pulmonary sequestration requires angiographic visualization of the anomalous feeding and draining vessels. The authors report a young woman who presented with persistent cough of two months' duration. Diagnosis of pulmonary sequestration was established with magnetic resonance (MR) angiography, which demonstrated abnormal feeding arteries to the sequestrum from the thoracic aorta with draining pulmonary veins.

Doses to operators during interventional radiology procedures: focus on eye lens and extremity dosimetry.

The present study is focused on the personnel doses during several types of interventional radiology procedures. Apart from the use of the official whole body dosemeters (thermoluminescence dosemeter type), measurements were performed to the extremities and the eyes using thermoluminescent loose pellets. The mean doses per kerma area product were calculated for the monitored anatomic regions and for the most frequent types of procedures. Higher dose values were measured during therapeutic procedures, especially embolisations. The maximum recorded doses during a single procedure were 1.8 mSv to the finger (nephrostomy), 2.1 mSv to the wrist (liver chemoembolisation), 0.6 mSv to the leg (brain embolisation) and 2.4 mSv to the eye (brain embolisation). The annual doses estimated for the operator with the highest workload according to the measurements and the system's log book were 90.4 mSv to the finger, 107.9 mSv to the wrist, 21.6 mSv to the leg and 49.3 mSv to the eye. Finally, the effect of the beam angulation (i.e. projection) and shielding equipment on the personnel doses was evaluated. The measurements were performed within the framework of the ORAMED (Optimization of RAdiation Protection for MEDical staff) project.

Unilateral testicular microlithiasis associated with a seminoma.

Unilateral testicular microlithiasis is an uncommon entity that is important because of its association with malignancy. We describe a case in which the initial clinical presentation was that of metastatic cervical lymphadenopathy. Subsequent sonographic examination of the testes revealed right testicular microlithiasis and a small, hypoechoic, ill-defined mass, which proved to be a seminoma. Since testicular microlithiasis is highly associated with testicular malignancy, it cannot be considered a benign condition. Sonographic follow-up examinations are warranted in patients with testicular microlithiasis to detect the possible development of malignancy.

A left atrial pseudomass: potential pitfall at thoracic MR imaging.

We frequently observed a nodular soft-tissue structure in the region of the left atrium anterior to the orifice of the left inferior pulmonary vein on MR scans of the chest. To assess its morphologic characteristics and appearance, chest MR scans obtained in 49 patients were reviewed. ECG-gated conventional spin-echo T1-weighted and fast spin-echo (FSE) T2-weighted sequences were used. The location, morphology, and appearance of this soft-tissue structure was evaluated by two radiologists during one consensus reading. The pseudomass in the region of the left atrium was identified on the T1-weighted images in 25 of 49 patients. The structure was also identified on FSE T2-weighted images in 6 of these patients. On the T1-weighted images, its appearance was either linear (54%) or nodular (46%). In conclusion, a nodular soft-tissue mass anterior to the orifice of the left inferior pulmonary vein into the left atrium is a frequent finding on chest MR scans and should not be confused with an intra-atrial mass. Careful evaluation of the regional anatomy identifies this structure as extraluminal and helps to avoid misinterpretation of an intracardiac mass.

Sonographic findings in testicular sarcoidosis simulating malignant nodule.

Testicular involvement by sarcoidosis is rare. We report a case of a patient with known sarcoid who had a unilateral testicular nodule with apparent capsular invasion on sonography. The epididymis was normal on both sides. Despite these atypical features, pathology showed the nodule to be a sarcoid granuloma. In patients with sarcoidosis, the differential diagnosis of an intratesticular mass should include testicular involvement by sarcoid.

CT demonstration of a rapidly growing transitional cell carcinoma of the ureter and renal pelvis.

Transitional cell carcinoma (TCC) is the most common urothelial malignancy. We present a case of an exceptionally aggressive TCC involving the renal pelvis and ureter. To our knowledge, an upper tract TCC of such rapid growth has not been reported.

Why perirenal disease does not extend into the pelvis: the importance of closure of the cone of the renal fasciae.

OBJECTIVE: The prevailing concept is that lack of fusion of the anterior and posterior renal fasciae caudally (an open cone) allows free communication between the perirenal space and the extraperitoneal portion of the pelvis. However, perirenal disease rarely extends into the pelvis and an open cone has not been observed on CT scans. Accordingly, we determined the anatomy of the caudal extent of the cone of the renal fasciae in cadavers and on CT scans. MATERIALS AND METHODS: Anatomic dissections of the lower portion of the retroperitoneum and the extraperitoneal portion of the pelvis were made in eight cadavers. Two cadavers were intact, two had colored latex injected into the perirenal space before dissections, and the abdomens and pelves of four were sectioned transversely in 3- to 5-cm-thick slices. The renal fasciae were traced on transparent films placed on the cross sections, and computer-generated three-dimensional representations of the tracings were made. These anatomic findings were correlated with observations made on CT scans of 59 consecutive patients with diseases involving the lower part of the retroperitoneum and the extraperitoneal portion of the pelvis (32 patients with hemorrhage, 16 with inflammatory processes, and 11 with neoplastic conditions). RESULTS: The anatomic study showed that the anterior and posterior renal fasciae merge to form a single multilaminar fascia in the iliac fossa. Anteriorly, this common fascia is loosely connected to the parietal peritoneum. Posteriorly lies the caudal continuation of the posterior pararenal compartment. This joins with the laterocaudal continuation of the central part of the retroperitoneum, which contains the iliac vessels. The distal part of the ureter lies within the caudal continuation of the single multilayered renal fascia. The CT studies done in patients showed that extension of the perirenal processes to the pelvis and vice versa was both restrained and uncommon: no direct extension of any abnormalities was observed in either direction, and laminar thickening of the fasciae was seen in one fifth of the patients. Similarly, no inferior communication of the perirenal space with the anterior or posterior pararenal spaces was seen. CONCLUSION: There is an anatomic barrier between the inferior perirenal space and the extraperitoneal pelvis formed by the fusion of the leaves of the renal fasciae into a single multilaminar fascia that acts as a barrier of disease extension. The multilaminar nature of this fascia, however, may also act as a filter, allowing some permeability between its layers. This potential interlaminar pathway is rare and is manifested as fascial thickening on CT scans. This laminar filter-barrier observation explains the lack of extension of perirenal diseases into the pelvis.

Contrast-enhanced MRA in pre-embolization assessment of a pulmonary arteriovenous malformation.

We describe a case of a single pulmonary vascular malformation studied with a new contrast-enhanced three-dimensional MRA technique. Images provided the interventional radiologist with a pre-embolization road map from which information regarding the number and size of feeding and draining vessels was obtained accurately and noninvasively.

Medial border of the perirenal space: CT and anatomic correlation.

PURPOSE: To explore the mode of spread of disease between the perirenal space and the perivascular central retroperitoneum and to determine the anatomy along the medial border of the perirenal space. MATERIALS AND METHODS: Anatomic dissection, injection of latex, and observation of cross sections of the abdomen were performed in nine cadavers. Attention was paid to the juncture of the central prevertebral, perivascular, and extraperitoneal regions, and the perirenal space. Anatomic findings were correlated with observations made at computed tomography (CT) in 82 patients with retroperitoneal hemorrhage (n = 24), inflammation (n = 37), and neoplasia (n = 21) involving the perirenal spaces or the central retroperitoneum. RESULTS: Along most of the length of each kidney, no apparent fascia separates the perirenal space from the central retroperitoneum. At this location, septa between fat lobules form a fenestrated multitier barrier. These septa were imperceptible on CT scans obtained in healthy individuals. After injection of latex in cadavers, this potential barrier was seen. In the clinical study, spread of disease was allowed in only 38 (30%) of 128 instances of potential spread. Spread was facilitated along the renal vessels and the interlobular septa. CONCLUSION: Beyond the kidneys, the renal fascia is closed, forming a cone superiorly and an inverted cone inferiorly. A network of interlobular septa acted as a barrier or pathway to the free spread of disease from the perirenal space to the central retroperitoneum or from the central retroperitoneum to the perirenal space.

Hypogenetic lung syndrome: functional and anatomic evaluation with magnetic resonance imaging and magnetic resonance angiography.

A case of hypogenetic lung syndrome is described in which anatomic and functional information was obtained with use of ECG-triggered turbo (fast) spin-echo, cine, velocity-encoded cine, and contrast-enhanced magnetic resonance angiography (MRA) sequences. To the best of our knowledge, a complete functional and anatomic study of hypogenetic lung syndrome with MRI has not been previously reported.

Contrast-enhanced breath-hold MR angiography for evaluating patency of coronary artery bypass grafts.

OBJECTIVE: The purpose of this study was to evaluate the ability of contrast-enhanced breath-hold MR angiography to reveal patency of coronary artery bypass grafts (CABGs). SUBJECTS AND METHODS: We evaluated 45 grafts (29 saphenous vein bypass grafts, 12 left internal mammary artery grafts, and four right internal mammary artery grafts) for occlusion or patency. Fifteen patients who had undergone CABG surgery underwent three-dimensional breath-hold ECG-triggered contrast-enhanced MR angiography at 1.5-T and conventional coronary angiography imaging within 24 hr of each other. MR angiograms were evaluated independently by two radiologists. Agreement between MR angiography and coronary angiography (the reference standard) was measured using Cohen's kappa statistic. RESULTS: One saphenous vein bypass graft was revealed as occluded by coronary angiography but was shown as patent by MR angiography and was excluded from statistical analysis. MR angiography was in agreement with coronary angiography in 42 of 44 grafts (kappa = 90: p < .001; sensitivity, 93%; specificity, 97%). CONCLUSION: Contrast-enhanced breath-hold MR angiography is a promising, rapid, and useful diagnostic technique for detecting graft patency in patients who have undergone CABG surgery.

The use of helical CT and CT angiography to predict vascular involvement from pancreatic cancer: correlation with findings at surgery.

OBJECTIVE: The purpose of this study was to test the accuracy of helical CT with and without CT angiography to predict vascular involvement from pancreatic cancer and correlate the resultant images with findings at surgery. SUBJECTS AND METHODS: Helical CT and CT angiography was done in 84 patients who had adenocarcinoma of the pancreas to refine an integrated CT angiography protocol. Of these patients 38 underwent radical pancreatoduodenectomy. Vessel integrity of the superior mesenteric artery, superior mesenteric vein, and portal vein was assessed prospectively on both axial CT scans and CT angiograms and correlated with findings at surgery and in particular with the ability of the surgeon to dissect the tumor from these vessels along the vascular planes. RESULTS: CT angiograms were obtained in 82 (98%) of 84 studies. Of the 38 patients who underwent radical pancreatoduodenectomy, resection was aborted in 11 (29%) because of vascular encasement, Compared with axial CT images, CT angiography was more accurate at revealing unresectable cases. In all but one of 11 patients with vessel encasement (narrowing of the lumen) revealed on CT angiography, the lesion was unresectable. Vessel encasement was shown in only two of these 11 patients on axial CT images (of these two patients, one underwent tumor resection). The negative predictive value of a resectable tumor was 96% for CT angiography and axial helical CT compared with 70% for axial helical CT images alone (p = .021). CONCLUSION: Helical CT with CT angiography of the pancreas provides useful information about local vascular involvement from pancreatic carcinoma. Compared with conventional axial helical CT, the addition of CT angiography improves radiologists' ability to predict the resectability of pancreatic tumors.

Impact of graft material configuration on stent-graft endoleak in vitro.

PURPOSE: To assess the effect of different attachment patterns between graft materials and stents on type I endoleak. MATERIALS AND METHODS: Nitinol stents were covered with a coating of Tegaderm in either a straight-edged pattern across the stent cells or a contoured zigzag pattern conforming to the stent skeleton's honeycomb-shaped cells. The stent-grafts were deployed in an ex vivo circuit across a gap of tubing to simulate an aneurysm cavity. Fluid leaking from the gap for more than 30 minutes was recorded as endoleak. Two contoured attachment patterns (short and long necks) and four straight-edged patterns with necks of varying length were tested. Each experiment was repeated 15 times. RESULTS: The length of the aneurysm neck covered by the graft material was inversely related to the rate of endoleak. The zigzag pattern of graft attachment demonstrated significantly less endoleak than the straight-edged pattern in the setting of a short aneurysm neck (0.25 mL vs 47.3 mL). CONCLUSION: Adopting the contoured (zigzag) attachment of graft material to stents minimizes endoleak in vitro, particularly in the setting of a short aneurysm neck.

Contrast-enhanced 3D MRA with centric ordering in k space: a preliminary clinical experience in imaging the abdominal aorta and renal and peripheral arterial vasculature.

The objective of this study was to determine the clinical utility of a contrast-enhanced, centric reordered, three-dimensional (3D) MR angiography (MRA) pulse sequence in imaging the abdominal aorta and renal and peripheral lower extremity arteries. Twenty-eight MRA studies were performed on 23 patients and four volunteers at 1.5 T using a 3D contrast-enhanced, centric reordered pulse sequence. In 20 patients, the abdominal aorta and renal arteries were imaged, and in seven patients, the lower extremity arteries were imaged. In 19 patients, a total of 51 renal vessels were evaluated (33 renal arteries using .1 mmol/kg of gadopentetate dimeglumine and 18 renal arteries using .2 mmol/kg of gadoteridol). A total of 70 peripheral arterial segments were assessed using .2 mmol/kg of gadoteridol. Correlation with conventional angiography was made for the following 14 cases: renal artery stenosis (four cases), abdominal aortic stenosis (one case), arteriovenous fistula in a transplant kidney (one case), renal arteriovenous malformation (one case), common iliac artery aneurysms (one case), and peripheral lower extremity (six cases). Of the 70 peripheral arterial segments evaluated, in 35, there was correlation with x-ray angiography. The mean percent of aortic signal enhancement was significantly higher in the .2 mmol/kg dose group (370.8 +/- 190.3) than in the .1 mmol/kg dose group (184.5 +/- 128.9) (P = .02). However, there was no apparent difference between the two doses for visualization of the renal and accessory renal arteries. There was concordance between the contrast-enhanced 3D MRA studies and conventional angiography in all cases of renal artery and peripheral arterial stenoses and occlusions, including visualization of reconstituted peripheral arterial segments. There was no evidence of spin dephasing effects at sites of stenoses on the 3D contrast-enhanced MRA studies. Contrast-enhanced, centric reordered, 3D MRA can rapidly image the abdominal aorta and renal and accessory renal arteries, as well as peripheral lower extremity arteries, with high resolution. Accurate depiction of the vascular lumen at sites of stenosis is made because of the lack of spin dephasing effects, even with hemodynamically significant stenoses. Additional larger clinical trials are required with this promising technique.

Pelvic endometriosis: MR imaging spectrum with laparoscopic correlation and diagnostic pitfalls.

Endometriosis is a common multifocal disease involving a number of anatomic sites in the pelvis. Although laparoscopy is the standard of reference for diagnosis, magnetic resonance (MR) imaging is a noninvasive method for evaluating areas inaccessible to laparoscopy. A large endometrioma (> or = 1 cm in diameter) appears as a homogeneously hyperintense mass on T1-weighted MR images and as a low-signal-intensity mass with areas of high signal intensity on T2-weighted images. A small endometrioma may be indicated when a pelvic mass less than 1 cm in diameter is hyperintense on T1-weighted images irrespective of its appearance on T2-weighted images. Endometriosis may also manifest as multiple, homogeneously hyperintense cysts on T1-weighted images. Involvement of the alimentary tract or bladder can appear as areas of high signal intensity. Although MR imaging is limited in its ability to depict small endometrial implants and adhesions, the advantages of MR imaging over laparoscopy include the ability to characterize endometriotic lesions and to evaluate extraperitoneal sites of involvement, contents of a pelvic mass, or lesions hidden by dense adhesions. The roles of the two modalities are therefore complementary. Knowledge of the variety of MR imaging appearances of endometriosis and organ involvement within the pelvis is important for guiding a subsequent laparoscopic examination.

Primary angiosarcoma of the spleen--CT, MR, and sonographic characteristics: report of two cases.

Primary angiosarcoma of the spleen is a rare entity, but it is the most common primary splenic malignancy. These tumors demonstrate an aggressive growth pattern and can be single or multiple. The diagnosis should be suspected in a patient who presents with splenomegaly but without evidence of lymphoma, malaria, leukemia, or portal hypertension. The tumor may also present with acute abdominal symptoms secondary to spontaneous splenic rupture. We describe two cases of primary angiosarcoma of the spleen with computed tomographic, magnetic resonance, and sonographic features.

MR cholangiopancreatography (MRCP).

Magnetic resonance cholangiopancreatography (MRCP) is an evolving new technique for noninvasive imaging of diseases of the biliary tree and pancreatic duct. The advantage of this method is that one can obtain maximum intensity projection (MIP) images of the pancreatico-biliary system similar to those obtained with endoscopic retrograde cholangiopancreatography (ERCP) without the need of administration of intravenous or oral contrast. Heavily T2-weighted sequences are used that render the bile and the intraductal pancreatic fluid bright against a dark background.