Biomedical subjects
Publications and source records attributed to G B Lund.
This report presents a case of left ventricular intramyocardial dissection masquerading as a ventricular pseudoaneurysm, as documented by echocardiography, magnetic resonance imaging, and angiography with subsequent confirmation at operation.
A set of MRI images with various degrees of phase encoding were generated from the same raw data set. The resultant pictorial teaching aid is useful in developing an intuitive understanding of the mechanics and principles of phase encoding in two dimensional, Fourier transform magnetic resonance imaging.
Biliary tract complications are a continuing source of morbidity after liver transplantation. In a 3.5-year period we performed 264 liver transplants in 226 patients (132 adults, 94 children). Biliary tract reconstruction was via Roux limb choledochojejunostomy (n = 144) or choledochocholedochostomy (n = 118). Fifty (19.1%) biliary complications occurred, and 35 (13.4%) necessitated operative repair. The incidence was similar in adults and children and after each method of reconstruction. Risk factors were vascular thrombosis and reduced-sized transplants. Diagnosis was based on the algorithmic use of multiple modalities with early biliary visualization. Roux limb complications usually occurred in the first month after transplant and necessitated operative intervention, whereas duct-to-duct problems appeared later and were more accessible to percutaneous or endoscopic manipulations. Eight (6.8%) patients required conversion to a Roux limb, whereas 8/15 (53.3%) cases of biliary stricture were successfully managed nonoperatively. Three (1.3%) patients and four (1.5%) grafts were lost as a result of biliary complications. One-year actuarial patient survival is 76.4% with a mean follow-up of 13.2 months. Early recognition of biliary complications and prompt interventional therapy can effectively prevent long-term sequelae. Although choledochocholedochostomy is more physiologic and expeditious, Roux-en-Y choledochojejunostomy remains a safe and versatile alternative and is the preferred method of reconstruction in select cases.
Percutaneous techniques to manage urinary fistulas have had limited success. To overcome this, self-closing metallic clips were developed to occlude the ureter. The clips are applied through a percutaneously placed 30-F Teflon sheath. A case is reported in which the clips and new technique were successfully used.
A new technique for the percutaneous extraction of ureteral calculi is described. A jet of CO2 is injected through a retrograde ureteral catheter to dislodge ureteral stones. This safe and simple technique has been successfully used in ten patients.
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An 11 year study is presented comprising 74 diabetic patients with terminal uraemia treated with dialysis and transplantation. The cumulative patient survival rate after one year is 45%. No difference is found between the survival rates of transplanted and dialysed patients. Sixty-six percent of the patients died from cardiovascular-, and 21% from infectious causes.
PURPOSE: Evaluate retrospectively the long-term primary patency of directional atherectomy (DA) in the femoropopliteal arteries. MATERIALS AND METHODS: DA was used alone in 59 patients (47%) or in combination with predilatation to allow passage of the device (43%) or after thrombolysis (10%) to treat 127 (93%) excentric atherosclerotic stenoses and nine (7%) occlusions of the femoropopliteal arteries. Forty-eight patients were followed by telephone interview, scheduled outpatient visits, color-flow Doppler evaluation, and angiography for 1-36 months (mean 16.9 months). RESULTS: Technical success (reduction of the stenosis or occlusion to less than 30% luminal diameter) was achieved in 110 lesions (80.3%) during 48 procedures in 37 patients. Mean luminal diameter was increased 54% with a concomitant increase in mean ankle/brachial indices of 0.33. According to Kaplan-Meier survival curves, patency at 12 and 24 months was 88% and 75%, respectively. When patients who retained patency but developed restenosis were excluded, the probability of patency at 12, 24, and 36 months was 76%, 58%, and 32%, respectively. Major and minor complications occurred in 15 (21.4%) procedures each for a total complication rate of 42.8%. CONCLUSION: Based on our results, DA is an effective method for percutaneous treatment of atherosclerotic disease involving the femoropopliteal arteries. It has similar patency but a relatively high complication rate compared with PTA.
Pseudoaneurysms due to chronic pancreatitis can be a source of major gastrointestinal (GI) hemorrhage. Computed tomography (CT) is the primary diagnostic imaging modality for pancreatic pseudocysts associated with GI bleeding. Pseudoaneurysms and associated GI bleeding can be diagnosed and embolized with transcatheter techniques once the arterial anatomy is defined. CT is a useful modality for follow-up examination of the pseudocyst; the findings must be correlated with other procedures performed on these patients. On follow-up studies, contrast medium retained in the pseudocyst after embolization may falsely signal persistent bleeding into the pseudocyst.
The growth of interventional radiology has contributed to the development of more complex procedures applicable to an increasing patient population, with maintenance of low complication rates. However, due to its invasive nature, potential complications will always be associated with each procedure. Prompt recognition of these complications allows for rapid treatment with decreased patient morbidity and mortality. This overview provides detailed statistics and diagnostic imaging for evaluation of a wide spectrum of complications from hepatobiliary, renal, and vascular interventional procedures.
PURPOSE: To assess the efficacy of chemoembolization of liver tumors by determining the fraction of viable tumor cells remaining after treatment with use of diffusion magnetic resonance (MR) imaging and histologic analysis. MATERIALS AND METHODS: VX2 tumor was grown in the livers of 12 rabbits. Animals were divided into a chemoembolization group and an untreated group. Conventional, perfusion, and diffusion MR imaging was performed on all rabbits. Histopathologic analysis of explanted livers was performed to document tumor cell death and measure Bcl-2 levels (inhibitor of apoptosis). RESULTS: Diffusion-weighted MR imaging delineated zones of tumor cell death as regions of lower signal intensity in both groups. Apparent diffusion coefficients were significantly greater in the area of tumor necrosis than in the area of viable tumor. Histologic analysis demonstrated a significantly lower percentage of viable cells in the treated group (<1%) than in the control group (55%). Bcl-2 expression detected within the viable areas of the tumor was greater in the treated group than in the control group. CONCLUSIONS: Chemoembolization causes extensive tumor cell destruction. Diffusion MR imaging can detect tumor cell death and can be used to assess the efficacy of chemoembolization. Bcl-2 was expressed in the treated group, suggesting an apoptotic pathway of cell death.
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PURPOSE: This study was undertaken to determine the efficacy of celiac plexus block (CPB) as a method of providing analgesia for percutaneous biliary drainage (PBD). PATIENTS AND METHODS: Thirty-two patients scheduled to undergo PBD were prospectively assigned randomly into placebo (30 mL of normal saline) and treatment (30 mL of 0.25% bupivacaine) CPB groups. Each patient received .03 mg/kg of midazolam for premedication before PBD and had access to a patient-controlled analgesia pump during the procedure. The pump was set to deliver 0.2 mg of midazolam and 25 micrograms of fentanyl per dose with a 3-minute lockout time. Vital signs, including heart rate and blood pressure, were continuously monitored during the procedure and recorded for comparison with baseline values. Patients completed a 10-point visual analogue pain scale following completion of their procedure. RESULTS: Patients in the placebo and treatment groups self-administered a mean of 2.0 and 1.85 mg of midazolam, respectively (P = .40), and a mean of 247 and 231 micrograms of fentanyl, respectively (P = .40). On a 10-point pain scale, the mean postprocedure versus preprocedure elevation in pain was 2.1 points in the placebo group versus 1.6 points in the treatment group (P = .60). Overall, the degree of satisfaction with the analgesia was equal in both groups. CONCLUSION: This study indicates that CPB is not an effective means of providing additional visceral pain relief over and above that which can be accomplished with self-administered intravenous medication for patients who undergo PBD.
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PURPOSE: The authors evaluated the technical success and immediate and long-term results of percutaneous varicocele embolotherapy in the adolescent population. PATIENTS AND METHODS: Fifty-nine adolescent patients were referred for outpatient spermatic venography and possible varicocele embolotherapy. Embolization was attempted with use of detachable balloons, coils, "sandwiched" dextrose, or a combination of these techniques. Data regarding follow-up were obtained through telephone interviews or mailed questionnaires. RESULTS: The technical success rate for spermatic vein occlusion was 90%. Follow-up, obtained in 79% of the patients, ranged from 6 months to 8.75 years (mean, 4 years). Thirty-nine of 42 patients (93%) reported disappearance (n = 31) or only a slight, asymptomatic residual varicocele (n = 8). Three patients reported a recurrence of their varicocele. Complications occurred in three of 59 cases (5%), none had any long-term sequelae. In six cases, embolization was not feasible because of multiple collateral vessels or venous spasm. CONCLUSIONS: Given the convenience of performing the procedure on an outpatient basis, the rapid recovery time, and long-term success and complication rates comparable to those with surgical ligation, we believe spermatic venography and percutaneous embolization is the treatment modality of choice for adolescent varicocele.
PURPOSE: The authors summarize their 11-year experience with percutaneous varicocele occlusion at the Johns Hopkins Hospital. PATIENTS AND METHODS: Data were obtained from the patients' medical records and from a mailed questionnaire. Most of the data analysis is based on the 182 patients who responded to the questionnaire. RESULTS: Most of the occlusions were performed for infertility. The mean length of time couples had been attempting to conceive was approximately 44 months. Occlusion was technically successful in 95.7% of cases. Patients were followed up for a mean period of 59 months. Success is difficult to define because many patients and/or their wives received additional infertility treatment. Fifty-seven percent of all couples and 60% of a subgroup of couples who received no other treatment eventually conceived. CONCLUSION: Percutaneous occlusion is a well-established treatment for varicoceles. Pregnancy rates and recurrence rates are comparable to those following surgical varicocelectomy. It is unlikely that resultant pregnancies occur from random chance alone.
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PURPOSE: This study assessed the technical feasibility and safety of repeat dilation of Palmaz stents in growing pulmonary arteries. MATERIALS AND METHODS: Palmaz stents (1.2 cm long) were placed percutaneously into the pulmonary arteries of 20 newborn lambs. After 4 months, pulmonary arteriography was performed. Where vessel growth in excess of stent diameter had created a stenosis (> 15%), stents were dilated again percutaneously. Six months later, pulmonary arteriography was performed, before the animal was killed and histologic examination performed. RESULTS: Twenty-four pulmonary artery stent placements were attempted; 23 were successful. One stent placement was unsuccessful owing to stent displacement from the balloon. Acute complications included branch pulmonary artery occlusion (n = 3) and stent displacement from the delivery balloon (n = 2). At 4 months, the desired degree of stenosis (> 15%) was achieved in 11 animals. The average stenosis was 35% (standard deviation, 16%; range, 17%-66%). The mean predilation stent diameter was 6 mm +/- 1.1 (range, 4-8 mm), and the final diameter of 8 mm +/- 1.4 (range, 6-10 mm), represented a 35% mean increase (P < .001). Complications included stent (n = 1) and branch vessel (n = 1) thrombosis. At 6-month follow-up, all stents were patent. Areas of previously noted branch thrombosis were fully recanalized in all cases. At histologic inspection, only a thin layer of neointima was found on the stents. CONCLUSION: Repeat dilation of Palmaz stents may be safely performed in growing pulmonary arteries in an animal model. Neointimal hyperplasia is minimal in pulmonary artery stents.