Endovascular Treatment of Arteriovenous Fistula with Pseudoaneurysm at Popliteal Fossa Using a PTFE Stent-graft: A Case Report

We report the successful treatment of a postoperative pseudoaneurysm of a popliteal artery, which was associated with an arteriovenous fistula to the popliteal vein using an endovascular placement of a PTFE-covered stent graft. After a one-month follow-up, there was an in-stent stenosis, which was managed by balloon angioplasty. The patient was well with mild leg discomfort after a 3-month follow-up.

Radiofrequency Ablation of the Gastrointestinal Tract with a Stent-Like Electrode: Experimental Study

OBJECTIVE: To assess the technical feasibility of a newly designed stent-like electrode in rabbits. MATERIALS AND METHODS: A stent-like electrode was knitted from a single thread of nitinol wire and interconnected to a generator using similar wire. In order to gauge the extent of radiofrequency ablation (RFA), we measured the depth of the ablated area in cow liver using a combination of 180-sec time intervals and 20-watt power increments. For data processing, Cox regression analysis was used. RFA was also applied to the small intestine of rabbits using this stent-like electrode under six different sets of conditions: 10 watts for 1 min, 10 watts for 2 mins, 20 watts for 1 min, 20 watts for 2 mins, 30 watts for 1 min, and 30 watts for 2 mins. To determine the gross and microscopic findings, six animals were sacrificed immediately after the procedure and the results obtained under the different sets of conditions were correlated. Eight rabbits were monitored for 4 weeks prior to sacrifice. RESULTS: For both ex-vivo and in-vivo ablations, the depth of the thermal lesion showed linear correlation with both the duration of RFA and the power applied. RFA of the duodenum was technically successful in all 14 rabbits. The acute changes occurring in the rabbits' small intestine included color change, cytoplasmic denaturation, fibrin deposition and hemorrhage, among which hemorrhage of the mucosal layer was the earliest finding. RF ablation for 2 mins at 30 watts caused serosal hemorrhage. The gross and histologic changes occurring showed close correlation under all six sets of conditions. CONCLUSION: Use of the stent-like electrode proves technically feasible but to determine the nature of the chronic change occurring in the gastrointestinal tract after RF ablation, further investigation and long-term follow-up in animals are required.

The Study to Factors indnced Human Error

No abstract available.

Evaluation of the Pedal Artery: Comparison of Three-dimensional Gadolinium-Enhanced MR Angiography with Digital Subtraction Angiography

PURPOSE: To compare the three-dimensional gadolinium-enhanced MR angiography with digital subtraction angiography (DSA) for evaluation of the pedal artery. MATERIALS AND METHODS: In 12 extremities of 11 patients, both digital subtraction angiography (DSA) and contrast-enhanced MR angiography (CE-MR angiography) were performed during the same week. Among ten of the 11 patients, the following conditions were present: atherosclerosis (n=4), diabetic foot (n=3), Buerger's disease (n=1), calciphylactic arteriopathy (n=1) and arteriovenous malformation of the foot (n=1). The remaining patient underwent angiography prior to flap surgery. For MR angiography, a 1.5T system using an extremity or head coil was used. A three-dimensional FISP (fast imaging with steady state precession) sequence was obtained before enhancement, followed by four sequential acquisitions (scan time, 20 secs; scan interval time, 10 secs) 10 seconds after intravenous bolus injection of normal saline (total 10 cc), following intravenous adminstration of gadolinium (0.02 mmol/kg, 3 ml/sec). Arterial segments of the ankle and foot were classified as the anterior or posterior tibial artery, the distal peroneal artery, the medial or lateral plantar artery, the pedal arch, and the dorsalis pedis artery. Two radiologists independently analysed visualization of each arteraial segment and the mean of visible arterial segments in one extreminty using CE-MR angiography and DSA. RESULTS: Among 84 arterial segments, 16 were invisible at both CE-MR angiography and DSA, while 39 were demonstrated by both modalities. Twenty-six segments were visible only at CE-MR angiography and three only at DSA. CE-MR angiography displayed a higher number of arterial segments than DSA (mean, 5.42 vs. mean 3.50, respectively), a difference which was statistically significant (p<0.000). The difference between each arterial segment was not statistically significant, except for the dorsalis pedis artery (t test, p<0.000). CONCLUSION: In that it provides additional information for the planning of treatment of lower-extremity arterial disease, three-dimensional CE-MR angiography is superior to DSA for evaluation of the pedal artery.

The Usefulness of Three-Dimensional Gadolinium-Enhanced MR Venography for the Evaluation of Varices in Lower Extremities

PURPOSE: To assess the performance of contrast-enhanced three-dimensional(3-D) magnetic resonance venography (MRV) of the pelvis and lower extremities in patients with varicose veins. MATERIALS AND METHODS: Ascending and MR venography were performed in seven legs of seven patients, and duplex Doppler sonography and MR venography in 15 legs of 12 patients, all referred for evaluation of varicose veins. For analysis, the venous system as revealed by ascending and MR venographic images was divided into 13 segments. For detection of reflux to the great saphenous vein, duplex Doppler sonography and MRV were performed. RESULTS: In ascending venography and MRV, 91 venous segments were potentially visible; both modalities depicted 78 of these, but failed to detect four. Ascending venography and MRV detected 17 and 19 varices, respectively. When two tourniquets were placed around the ankle and knee using the Valsalva maneuver, MRV and duplex Doppler sonography detected reflux in 8 of 11 and 13 of 15 legs, respectively. CONCLUSION: Contrast-enhanced 3-D MRV comprehensively displays the venous system of the lower extremities and permits assessment of varicose veins. MRV using the Valsalva maneuver allows assessment of reflux to the great saphenous vein.

Radiofrequency Ablation of Lung Cancer: Preliminary Report

PURPOSE: Radiofrequency ablation (RFA) of lung cancer in animals and humans has been described in previously published reports. The aim of this study was to present our preliminary experience of treatment of lung cancer involving this approach. MATERIALS AND METHODS: Eight patients with lung malignancies [stage IIIB or IV bronchogenic adenocarcinoma (n=6), metastatic squamous cell carcinoma (n=1), metastatic hepatocellular carcinoma (n=1)] underwent RFA treatment. In all cases LeVeen-type electrodes were employed and CT was used to monitor the procedure. One-day and one-month follow-up CT scans were obtained and analyzed. RESULTS: Prior to treatment, tumor diameter ranged from 2.5 to 5 cm; afterwards, low attenuation consistent with coagulative necrosis was observed. Complications included a small amount of pneumothorax (n=4), pleural effusion (n=8), and subcutaneous emphysema (n=1). Tumor size decreased in five patients, was unchanged in two, and increased in one. CONCLUSION: Radiofrequency ablation of lung cancer is safe and may result in a reduced tumor burden.

CT Findings of Orbital Blow-out Fracture

PURPOSE: To evaluate the usefulness and radiologic findings of CT in the diagnosis of orbital blow-outfracture. MATERIALS AND METHODS: Forty-four patients with orbital blow-out fractures diagnosed by clinicalfindings and CT were evaluated retrospectively. On CT images, we evaluated the site and frequency of fracture,herniation of orbital fat, extraocular muscle abnormality, intraorbital hematoma, and intrasinus hemorrhage. RESULTS: Forty-eight sites of orbital wall fractures were seen. Of these, 25(52.1%) were observed at the medialwall and 18(37.5%) at the inferior wall. Combined fracture of the medial and inferior wall was seen in fivecases(10.4%), and orbital fat herniation to adjacent sinuses in 25. Associated extraocular muscle abnormalitieswere seen at the medial rectus (n=20) and inferior rectus muscle(n=18). Intrasinus hemorrhage was seen in 15cases, and intraorbital hematoma in five. CONCLUSION: CT is a useful diagnostic modality for the evaluation oforbital blow-out fracture and associated soft tissue abnormalities.

Evaluation of the MR Imaging Findings of Ankylosing Spondylitis involving the Thoracolumbar Spine

PURPOSE: To evaluate the MR imaging findings of ankylosing spondylitis involving the thoracolumbar spine. MATERIALS AND METHODS: We retrospectively analyzed MR imaging findings in ten patients with ankylosing spondylitisinvolving the thoracolumbar spine. All were male and ranged in age from 24 to 47 (mean, 33)years. MR images wereobtained using a 1.5T imager, and signal intensity changes of vertebral bodies were evaluated on sagittal T1- andT2-weighted images. Plain radiographic findings were also evaluated. RESULTS: On T1-weighted images, five casesshowed focal high-, two cases low-, two cases high- and low-, and one case iso-signal intensities at the cornersand/or along the anterior borders of the vertebral bodies. On T2-weighted images, seven cases showed focal high-and three, iso-signal intensities in those areas of the vertebral bodies. In one case which showed focal highsignal intensity on T1-weighted images and iso-signal intensity on T2-weighted images, multiple Schmorl's nodeswere seen in thoracolumbar spines. In all cases, signal intensity changes were more prominent in anterior portionsof the vertebral bodies. The shapes of abnormal signal intensities were vertical wedge, vertical band, and rounddot. Plain radiographs showed bamboo spine in three cases, squaring and focal sclerosis of vertebral bodies intwo, focal syndesmophyte in one, Schmorl's node in one, and no abnormal findings in three. CONCLUSION: Characteristic MR imaging findings of ankylosing spondylitis involving the thoracolumbar vertebral bodies werefocal signal intensity changes at the corners and along the anterior borders of the vertebral bodies.