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OBJECTIVE. The purposes of this study were to estimate the blood volume flow of the lower extremities by means of Doppler technique; to establish a quantitative relationship between volume flow and pulsatility index (PI) in both healthy subjects and patients with peripheral artery disease (PAD); and to derive arterial blood flow equations in the lower extremities for more accurate volume flow estimations. SUBJECTS AND METHODS. Sixty healthy subjects were recruited. Arterial diameter, peak systolic velocity, PI, time-averaged mean velocity, and volume flow of right lower extremity arteries were measured with duplex Doppler ultrasound. Linear regression analysis was used to evaluate the relationship between volume flow and the reciprocal of PI. This quantitative relationship was also used to assess flow changes in 10 patients with PAD before, after, or both before and after percutaneous angioplasty. RESULTS. Volume flow in the common femoral artery was 434.4 mL/min; superficial femoral artery, 172.5 mL/min; popliteal artery, 92.1 mL/min; dorsalis pedis artery, 11.8 mL/min; and common plantar artery, 12.0 mL/min. Linear relationships between the reciprocal of PI and volume flow were found and expressed as linear blood flow equations. For the patients with PAD, no statistical increase in measured flow in the downstream artery after percutaneous angioplasty was found ( p = 0.1), although four arteries had decreased flow. After normalization of flow measurements with PI values, however, statistical increases were observed between percentage increment ( p < 0.001) calculations. CONCLUSION. When real-time PI values are factored into blood volume flow calculations in the evaluation of lower extremity arteries, discrepancies in flow measurements can be resolved, resulting in more accurate and stable measurements of clinical and diagnostic significance.

Objective: The purpose of this study was to describe our technique of transhepatic serial puncture of the portal vein and hepatic vein-inferior vena cava in one needle pass under ultrasound guidance to place a transjugular intrahepatic portosystemic shunt (TIPS) in patients with a porta hepatis cranial to the usual location., Materials and Methods: Six patients (five men, one woman) underwent transhepatic TIPS procedures at our institution. The indications for portal decompression were recurrent variceal bleeding in four patients and refractory ascites and hydrothorax in one patient each. In five patients initial attempts at a classic transjugular approach failed because of an unusual angle between the hepatic vein and the portal vein; in the other patient, revision of an occluded shunt had failed. Two patients had main portal vein thrombosis., Results: Technical success was achieved in all six patients. Two patients received a portohepatic venous shunt and four a portocaval shunt (inferior vena cava to right portal vein in three patients and inferior vena cava to left portal vein in one patient).The portosystemic pressure gradient before TIPS was 17-35 mm Hg and after TIPS was 6-10 mm Hg. No procedure-related complications occurred. One patient had severe hepatic encephalopathy. Two patients had shunt occlusion, which was successfully revised 17 and 10 months after the procedure., Conclusion: Our technique is a safe, effective, and universally applicable method for establishment of a TIPS in patients with either normal venous anatomy or severely distorted liver parenchyma.

Objective: The purpose of this study was to describe the technique of antegrade retrieval of ureteral stents under fluoroscopic guidance through an 8-French nephrostomy., Materials and Methods: During an 8-year period, we retrieved 26 ureteral stents from 24 patients who were not candidates for retrograde removal or had other conditions precluding use of a retrograde approach. A loop snare or grasping forceps was used to retrieve a ureteral stent in the renal pelvis or calyx or upper ureter through an 8-French vascular sheath with a safety wire in place. A snare catheter advanced into the bladder for retrieval of the bladder end was used in patients in whom retrieval with both a loop snare and a grasping forceps failed., Results: All 26 ureteral stents were successfully retrieved by the antegrade approach. Ten stents were retrieved with a snare alone and nine with a forceps alone. Five stents were retrieved successfully with a forceps after initial failures with snare catheters. Two stents were retrieved with snare catheters advanced into the bladder. The major complication of nephrostomy wound infection occurred in a patient with a urinary tract infection who underwent a one-stage procedure. All minor complications, including pelvic perforation in one patient and blood clot in the renal pelvis in four patients, resolved spontaneously without adverse sequelae., Conclusion: Antegrade percutaneous retrieval of a ureteral stent through an 8-French nephrostomy is safe and effective and has a high degree of technical success. It can be used as a routine interventional practice in radiology.

Objective: The purpose of this study was to review our experience with fluoroscopically guided retrograde exchange of ureteral stents in women., Materials and Methods: During a 48-month period, 28 women (age range, 38-76 years) were referred to our department for retrograde exchange of a ureteral stent. The causes of urinary obstruction were tumor compression in 26 patients and benign fibrotic stricture in two patients. A large-diameter snare catheter (25-mm single loop or 18- to 35-mm triple loop) or a foreign body retrieval forceps (opening width, 11.3 mm) was used to grasp the bladder end of the stent under fluoroscopic guidance. The technique entailed replacement of a patent or occluded ureteral stent with a 0.035- or 0.018-inch guidewire with or without the aid of advancement of an angiographic sheath., Results: A total of 54 ureteral stents were exchanged with a snare catheter in 42 cases or a forceps in 12 cases. One stent misplaced too far up the ureter was replaced successfully through antegrade percutaneous nephrostomy. Ten occluded stents, including one single-J stent, were managed with a 0.018-inch guidewire in three cases, advancement of an angiographic sheath over the occluded stent into the ureter in five cases, and recannulation of the ureteral orifice with a guidewire in two cases. No complications of massive hemorrhage, ureter perforation, or infection were encountered., Conclusion: With proper selection of a snare or forceps catheter, retrograde exchange of ureteral stents in women can be easily performed under fluoroscopic guidance with high technical success and a low complication rate.

Objective: Our purpose was to evaluate the safety and therapeutic efficacy of single-session prolonged alcohol sclerotherapy in treating large hepatic cysts. A therapeutic comparison between 4-hour and 2-hour retention techniques was also studied., Materials and Methods: Twenty-seven patients with 31 hepatic cysts were enrolled in this study. Seventeen patients (18 cysts) were treated by alcohol retention for 4 hours (group 1) and 10 patients (13 cysts) for 2 hours (group 2). The mean diameter of the hepatic cysts was 12.4 cm (range, 8-23 cm) with a comparable size range in each group. The sclerosing agent used was 95% alcohol, and the maximum amount was limited to 200 mL. Patients changed position and vital signs were monitored every 10-15 minutes. The blood alcohol concentrations were checked hourly for 5 consecutive hours in the initial nine patients. The nonparametric Mann-Whitney U test was used to compare the difference in characteristics and treatment results of the subjects between these two groups. The level of statistical significance was set at a p value of less than 0.05., Results: All but one patient in group 2 tolerated the entire course of sclerotherapy. The mean aspirated volume and mean injected alcohol volume of the hepatic cysts were 730 mL and 138.3 mL, respectively, in group 1 patients, and 931 mL and 139 mL, respectively, in group 2 patients. The mean maximum blood alcohol concentration was 128.2 mg/dL (range, 60-199 mg/dL) at 3-4 hours after alcohol instillation. The mean posttherapy residual cystic diameter was 2.5 cm (range, 0-6 cm), with an average volume reduction rate of 98.3% and 97.7%, respectively, for patients in group 1 and group 2 after a mean follow-up period of 29.6 months (9-59 months). No statistical differences of the mean reduction rate between the two groups were noted., Conclusion: Long retention of the alcohol in a single-injection technique is safe and effective. Two-hour alcohol retention has a comparable efficacy to that of 4-hour retention.

Objective: The objectives of our study were to evaluate the feasibility of ethanol sclerotherapy in treating simple renal cysts with prolonged ethanol retention and to compare the therapeutic results of 2- and 4-hr retention techniques., Materials and Methods: We retrospectively reviewed 36 renal cysts in 33 patients treated by ethanol sclerotherapy with a single-session single-injection technique during the past 6 years. After complete aspiration of the cystic fluid, 95% ethanol was injected into the cyst and was retained for 4 hr in 14 cysts (group 1) and for 2 hr in 22 cysts (group 2). The average maximal diameter and aspirated volume of the cysts were 8.3 cm and 223 mL in group 1 patients and 7.9 cm and 167 mL in group 2, respectively. The ablated cysts were followed up regularly by sonography, CT, or both at 3- to 6-month intervals for at least 1 year. The nonparametric Mann-Whitney U test was used to compare differences in characteristics, treatment results, and laboratory data of the subjects in the two groups. The level of statistical significance was set at a p value of less than 0.05., Results: Technically, all the patients tolerated the procedures. One patient had gross hematuria 10 days after the procedure. She underwent surgical deroofing treatment and was excluded in the later statistical analysis. After sclerotherapy, 14 cysts disappeared completely and 16 cysts showed marked regression with residual maximal diameter of less than 3 cm. The overall volume reduction rate was 97.6% in all 35 cysts. The mean residual longest diameters and average volume reduction rates of the treated cysts were 1.9 cm and 97.9% in group 1 patients and 1.1 cm and 97.3% in group 2 patients, respectively, which showed no statistical significance of volume reduction rate with a p value 0.149., Conclusion: The single-session prolonged ethanol-retention technique is safe and efficacious for the treatment of renal cysts. There is no statistical difference in therapeutic efficacy between 2- and 4-hr ethanol-retention techniques.

Objective: The purpose of this study was to report our experience with metallic stent placement in the peripheral outflow veins in native arteriovenous fistula (A-V fistula) hemodialysis patients after insufficient balloon dilatation., Materials and Methods: During the past 4 years, 12 A-V fistula dialysis patients in our hospital underwent metallic stent placement in the peripheral outflow veins to restore vascular access. The indications for metallic stent placement in our study included (1) recoil stenosis of outflow vein in six patients; (2) outflow venous rupture in two patients and dissection in one patient; and (3) large residual adherent thrombus in outflow aneurysms in three patients with thrombosed (arteriovenous) access. Self-expandable Wallstent or Jostent (Jomed, Abbott Laboratories) of appropriate size (6-10 mm in diameter) was chosen for use in these patients. Kaplan-Meier survival analysis was used to calculate the access patency rates., Results: Twelve patients received stents. Eleven patients (92%) underwent successful dialysis after the procedure. One patient experienced complications due to incorrect positioning of the stent at the anastomotic site, causing flow compromise. The primary patency (+/- standard error) of the vascular access at 3, 6, 12, and 24 months was 92% +/- 8%, 81% +/- 12%, 31% +/- 17%, and 31% +/- 17%, respectively. The secondary patency of the vascular access at 3 months was 92% +/- 8%, and 82% +/- 12% at 6, 12, and 24 months each., Conclusion: Metallic stent placement is safe and effective in treating peripheral venous lesions in native A-V fistula hemodialysis patients after unsatisfactory balloon dilatation.

Objective: This study was performed to describe the association of posterocentral epidural cysts with interspinous bursal fluid in Baastrup's disease using MRI and interspinous bursography., Conclusion: Interspinous bursal fluid in Baastrup's disease can extend into the posterocentral epidural space and cause various degrees of central canal stenosis. Bursography alone or combined with CT allows documentation of abnormal communicating channels between the interspinous bursa and epidural cyst.

Objective: Prediction of postoperative lung function is important in preoperative evaluation of patients with lung cancer. Perfusion scintigraphy is the current method to assess the fractional contribution of lung function of the remaining lung. We developed a quantitative CT method and compared it with perfusion scintigraphy for predictions of postoperative forced expiratory volume in 1 sec (FEV1) in patients with lung cancer., Subjects and Methods: Forty-four patients with lung cancer undergoing lung resection with preoperative CT and perfusion scintigraphy were enrolled. Quantitative CT used a dual threshold (-500 and -910 H) on standard preoperative CT to semiautomatically extract lung volume without emphysema or tumor and atelectasis, which we defined as "functional lung volume." Prediction was calculated from preoperative FEV1 multiplied by the fractional contribution of functional lung volume of the remaining lung by quantitative CT. Perfusion scintigraphy was the standard method. Predictions were correlated with postoperatively measured FEV1., Results: Both quantitative CT and perfusion scintigraphy predicted postoperative FEV1 well in patients who underwent pneumonectomy (n = 28, r = 0.88 vs r = 0.86) and in lobectomy (n = 16, r = 0.90 vs r = 0.80) (both, p < 0.001). There was good agreement between the two methods by the Bland-Altman method. In the four patients with low measured postoperative FEV1 (<40% predicted normal), quantitative CT had true-positive prediction in four and perfusion scintigraphy, in only two., Conclusion: Given its simplicity, we proposed that quantitative CT be widely used in predicting postoperative FEV1.