Cost-effectiveness analysis of alternative strategies for palliation of distal biliary obstruction after a failed cannulation attempt.

OBJECTIVES: Occasionally alternative techniques such as precut sphincterotomy or percutaneous transhepatic cholangiography (PTC) are required to achieve access to the common bile duct. Tradeoffs exist, however, with respect to their complications and costs. Some experts believe that precut sphincterotomy should not be performed at all. We aimed to compare the cost-effectivenesses of metallic biliary stent placement after an initial failed cannulation attempt at ERCP utilizing precut sphincterotomy and placement utilizing PTC for palliation of jaundice. A cost-effectiveness analysis was performed, as viewed from the societal perspective. METHODS: A decision analysis model was designed comparing precut sphincterotomy and PTC approaches for placement of a metallic biliary stent for palliation of jaundice in a patient with inoperable malignant distal biliary obstruction in whom an initial attempt at ERCP cannulation had failed. Baseline probabilities, obtained from the published literature, were varied through plausible ranges using sensitivity analysis. Charges were based on Medicare professional plus facility fees or diagnosis-related group rates for out- and inpatients, respectively. The outcome measured was cost per year of life. RESULTS: Sensitivity analysis showed that precut sphincterotomy with subsequent PTC, if necessary, was the most cost-effective strategy provided the precut complication rate was <51% ($9,033/yr), versus $14,741/yr for PTC. CONCLUSIONS: Precut sphincterotomy followed by PTC (if necessary) is the most cost-effective strategy for palliative biliary stenting in the setting of malignant distal biliary obstruction after a failed ERCP attempt. The endoscopic approach is best practiced by experienced endoscopists who minimize precut complication rates.

Percutaneous transhepatic endoluminal biliary biopsy with use of a 19-gauge gun.

A technique was developed to perform endoluminal biliary biopsy with use of a commercially available 19-g gun. In 18 patients, a biopsy set consisting of an outer 7-F, 50-cm sheath, an inner curved 14-g metal cannula, and a 60-cm, 19-g biopsy gun with a 20-mm throw was employed to obtain tissue from suspicious-appearing biliary strictures via preexisting transhepatic tracts. The endoluminal biopsy was positive for neoplasm in 13 of 18 cases with three false negatives, one true negative, and one patient with insufficient follow-up. One biopsy was complicated by a hepatic artery pseudoaneurysm, which was successfully treated with coil embolization.

Long-term results of treatment for ureteroenteric strictures.

OBJECTIVES: To review the long-term outcome for ureteroenteric stricture treatment. METHODS: The ileal conduit diversions that formed ureteroenteric strictures from 1966 to 1999 were reviewed. The strictures were diagnosed radiographically, and malignancy was excluded. The treatment, location, length, diameter, and timing of stricture development after conduit creation was evaluated and compared regarding the time until stricture recurrence (failure). Success was defined as symptomatic improvement and radiologic evidence of patency. RESULTS: Forty patients, after exclusions, returned for ureteroenteric stricture repair, comprising 79 procedures (27 open repairs and 52 balloon dilations). The open repair had a success rate at 1, 2, and 3 years of 92%, 87%, and 76%, respectively. Seven of the open cases were preceded by failed dilations. Balloon dilation had a success rate at 1, 2, and 3 years of 15%, 15%, and 5%, respectively (P = 0.0001 versus open). Similar patency results for open versus balloon (P = 0.0001) were noted with analysis restricted to each patient's first stricture repair. Strictures greater than 1.0 cm were more likely to recur (P = 0.03). All strictures forming within 6 months of the conduit creation were treated with dilation and failed within 1 year. Of note, 11 of the 40 patients were found to have less than 25% renal function on the strictured side. CONCLUSIONS: Open repair for ureteroenteric strictures offers excellent long-term patency (76% at 3 years, P = 0.0001). On review, balloon dilation appeared to have less successful patency rates and was often followed by open repair after failure. Patients with a history of anastomotic strictures should be closely monitored to avoid renal damage and failure.

Image quality and dose comparison among screen-film, computed, and CT scanned projection radiography: applications to CT urography.

PURPOSE: To evaluate image quality and dose for abdominal imaging techniques that could be used as part of a computed tomographic (CT) urographic examination: screen-film (S-F) radiography or computed radiography (CR), performed with moving and stationary grids, and CT scanned projection radiography (CT SPR). MATERIALS AND METHODS: An image quality phantom underwent imaging with moving and stationary grids with both a clinical S-F combination and CR plate. CT SPR was performed with six CT scanners at various milliampere second and kilovolt peak settings. Entrance skin exposure (ESE); spatial, contrast, and temporal resolutions; geometric accuracy; and artifacts were assessed. RESULTS: S-F or CR images, with either grid, provided image quality equivalent to that with the clinical standard, S-F with a moving grid. ESE values for both S-F and CR were 435 mR (112.2 microC/kg [1 mR = 0.258 microC/kg]) with a moving grid and 226 mR (58.3 microC/kg) with a stationary grid. All CT SPR images provided inferior spatial resolution compared with S-F or CR images. High-contrast objects generated substantial artifacts on CT SPR images. Compared with S-F, CR and CT SPR provided improved resolution of small low-contrast objects. The contrast between iodine and soft-tissue-mimicking structures on CT SPR images acquired at 80 kVp was twice that at 120 kVp. CT SPR images with acceptable noise levels required a midline ESE value of approximately 300 mR (77.4 microC/kg) at 80 kVp. CONCLUSION: S-F and CR provided better spatial resolution than did CT SPR. However, CT SPR provided improved low-contrast resolution compared with S-F, at exposures comparable to those used for S-F or CR.

An auxiliary CT tabletop for radiography at the time of CT.

An auxiliary CT tabletop was designed and manufactured such that radiographic images might be acquired, with use of a ceiling-mounted X-ray tube, without removing the patient from the CT table. The tabletop required no modifications to the original CT table housing and did not produce artifacts in the CT images. Radiographs obtained with the overhead X-ray tube and auxiliary tabletop demonstrated image quality equivalent to traditional radiographs.

Renal cell carcinoma metastatic to the pancreas: clinical and radiological features.

OBJECTIVE: To review the clinical features, computed tomographic (CT) appearance, and treatment outcomes in a case series of patients with renal cell carcinoma (RCC) metastatic to the pancreas. PATIENTS AND METHODS: We retrospectively reviewed the records of 23 patients (15 men and 8 women) with RCC metastatic to the pancreas, detected by CT examination between 1986 and 1996. All patients had undergone a previous nephrectomy for RCC. RESULTS: Isolated mild elevation in liver function test results (in 5 patients) or in serum amylase level (in 8 patients) was observed. New-onset diabetes was detected in 3 patients. The CT characteristics of the pancreatic metastases generally resembled those of primary RCC with well-defined margins and greater enhancement than normal pancreas with a central area of low attenuation. The mean interval between resection of the primary RCC and detection of the pancreatic metastases was 116 months (range, 1-295 months). In 18 patients (78%), the pancreatic metastases were diagnosed more than 5 years after nephrectomy. The pancreas was the initial metastatic site in 12 patients (52%). Survival was shortened with higher tumor grade (mean survival time of 41 months and 10 months in patients with grade 2 and 3, respectively). Surgical resection was carried out in 11 patients (7 distal and 3 total pancreatectomies and 1 distal pancreatectomy followed 4 years later by total pancreatectomy), with 8 patients alive at a mean follow-up of 4 years, 6 of whom remained free of recurrence. Overall, 12 patients (52%) were alive at a mean of 42 months after diagnosis of metastatic disease. CONCLUSIONS: The appearance of metastatic RCC lesions in the pancreas closely resembles the appearance of primary RCC on CT images. Pancreatic metastases from RCC are frequently detected many years after nephrectomy. Patient survival correlates with tumor grade. Histologic analysis of pancreatic masses in patients with a history of resected primary RCC is important since the prognosis for RCC metastatic to the pancreas is much better than that for primary pancreatic adenocarcinoma.

Prediction of stone composition from plain radiographs: a prospective study.

BACKGROUND AND OBJECTIVES: Stone composition, as reflected in radiographic appearance, is important to help choose between SWL and percutaneous/endoscopic procedures. Predicting a stone's composition accurately from a plain radiograph would be a useful tool in clinical decision-making. However, the ability of physicians to predict composition has not been adequately assessed. A prospective study was designed to quantify the accuracy of a panel of physicians who routinely deal with stones in classifying stone composition solely from radiographs. MATERIALS AND METHODS: A panel of six members was created to review 100 plain-film radiographs from patients with renal stones of known composition. The panel consisted of two urologists, two radiologists, and two nephrologists, all of whom have expertise in stone disease. If the composition guessed was at least 40% of the total stone composition, the response was deemed correct. RESULTS: Overall, there was an average 39% correct response score among the six panelists. When the stones were divided by size, 35% were <1 cm, and 65% were larger. The accuracy of chemical composition determination did not improve with greater stone size, nor was there a difference in accuracy for pure and mixed stones. The most frequently misclassified stone was calcium phosphate, with only 14% being correctly diagnosed. CONCLUSIONS: With a random sampling of plain radiographs, a panel of physicians specializing in stone disease correctly diagnosed the composition of renal calculi less than half of the time without being given clinical information.

Helical and electron beam CT scanning in the evaluation of renal vein involvement in patients with renal cell carcinoma.

PURPOSE: The purpose of this study was to assess helical and electron beam CT scanning in the evaluation of renal vein involvement in patients with renal cell carcinoma (RCC). METHOD: Seventy-three patients with 76 pathologically proven RCC who underwent surgical resection or autopsy were evaluated for the accuracy of helical and electron beam CT scanning in the detection of renal vein tumor thrombus in patients with RCC. Patients were entered into the study only if they were scanned on either electron beam or helical CT scanners with intravenous contrast medium enhancement. The tumors involved the right kidney in 38 cases and the left kidney in 38 cases, with tumor size ranging from 1.5 to 19 cm (mean 7 cm). The pathologic grade of the tumor was Grade I in 21, Grade II in 37, Grade III in 15, and Grade IV, in 3 patients. RESULTS: The accuracy of preoperative CT evaluation of the renal vein for presence or absence of tumor thrombus was 96%. The negative predictive value was 97% and the positive predictive value was 92%. Sensitivity was 85% with a specificity of 98%. In two cases we were unable to detect small intrarenal venous thrombus, although this was present on a microscopic level and did not affect surgical resection. A single false-positive CT result occurred secondary to unopacified blood flow from a capsular vein into the affected renal vein, resulting in a small flow void on CT. CONCLUSION: The data show that preoperative staging of the renal vein in the patients with RCC is effectively provided with helical and electron beam CT scanning.

Percutaneous antegrade endopyelotomy: review of 50 consecutive cases.

Between 1988 and 1993, 50 percutaneous antegrade endopyelotomies were performed for ureteropelvic junction obstruction at this institution. The success of the procedure was based on radiological parameters as well as patient symptomatology. The overall success rate of the procedure was 88%. Endopyelotomy was successful in 9 of 11 patients (82%) who presented after failing previous renal procedures. When endopyelotomy was used as the initial treatment modality the success rate was 90%. These results support the argument that endopyelotomy should be considered as first line therapy for most adults with ureteropelvic junction obstructions [corrected].

Diagnosis and treatment of nephrolithiasis: current perspectives.

Urinary stones are a frequent cause of morbidity in persons in affluent industrialized societies. The surgical management of symptomatic stones in the upper urinary tract has changed dramatically in the past generation, largely because of the introduction of progressively less invasive treatment techniques. The concurrent revolution in radiologic imaging and interventional techniques has mirrored the surgical experience. This article reviews the current diagnosis and therapy of nephrolithiasis. An evaluation of the complex metabolic abnormalities present in the population of patients with urolithiasis is beyond the scope of this article, but several good reviews of this subject have been published recently [1-4]. Because primary urolithiasis involving the bladder or urethra is less common and is a separate medical entity, this article is focused on renal and ureteral calculi.

Imaging of complications of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy has gained widespread acceptance for treatment of cholelithiasis. Because radiologists have a primary role in recognizing and treating complications of this surgical technique, we reviewed the clinical records and imaging studies of 29 patients with complications after laparoscopic cholecystectomy. Complications included bile duct injuries (15 cases), retained common bile duct stones (seven cases), cystic duct stump leak (four cases), bowel perforation (two cases), abdominal abscess (two cases), intraperitoneal gallstones (2), and failure to diagnose malignant bile duct obstruction (one case). Twenty-two patients required reoperation, and one patient with bowel perforation died. Eleven of 15 bile duct injuries were imaged prior to hepaticojejunostomy. Nine of 11 were proximal bile duct injuries within 2 cm of the junction of the right and left bile ducts. Endoscopic retrograde cholangiography (ERC) identified the distal extent of injuries, but transhepatic cholangiography (THC) was necessary to fully evaluate the proximal extent of the bile duct abnormalities. ERC was used for diagnosis and treatment of the seven patients with choledocholithiasis. Abdominal films showed intraperitoneal in one patient with bowel perforation, intraperitoneal stones in a second patient, and intraabdominal abscess in one of two patients in whom abdominal films were performed. Computed tomography (CT), done in three patients with bowel perforation or abscess, showed the one duodenal perforation, and the two abscesses. CT also showed bilomas, intraperitoneal gallstones, and unsuspected malignancy. Imaging studies detected and defined complications after laparoscopic cholecystectomy in all cases.

Idiopathic myelofibrosis with myeloid metaplasia involving the renal pelves, ureters and bladder.

Myeloid metaplasia associated with idiopathic myelofibrosis most commonly involves the reticuloendothelial organs, such as the spleen, liver and retroperitoneal lymph nodes. We report on a patient with myeloid metaplasia (extramedullary hematopoiesis) of the renal pelves, ureters and bladder. The pathogenesis, clinical characteristics, treatment and prognosis of this condition are discussed.

Early experience with percutaneous cholecystolithotomy.

Percutaneous cholecystolithotomy should be added to the list of alternatives to elective open cholecystectomy for the management of patients with gallstones. Our initial experience with percutaneous cholecystolithotomy in 13 patients (7 men and 6 women who ranged in age from 47 to 83 years) demonstrated that the procedure could be accomplished successfully with acceptable morbidity and no mortality. After a mean duration of follow-up of 10.7 months, only one patient had recurrent cholelithiasis. Because of rapid changes in the therapeutic approach to patients with cholelithiasis, percutaneous cholecystolithotomy may seldom be used.

Radiology in the intensive-care unit.

Portable chest radiography is an essential component of clinical patient management in the intensive-care unit. With routine use of this procedure, unexpected cardiopulmonary abnormalities are frequently detected, and malposition or complications of intravascular devices and endotracheal, thoracostomy, or nasogastric tubes are also commonly found. The pulmonary parenchyma may be assessed for changes of acute lung injury, cardiogenic edema, areas of pneumonitis, atelectasis, or other abnormal collections of fluid or air. In mechanically ventilated patients, barotrauma occurs frequently and may be manifested by subtle intrathoracic collections of air. Technical factors may limit the resolution of the anteroposterior chest radiograph obtained at the bedside, but crucial clinical information is often gained. Portable chest radiographic findings, the role of computed tomography and ultrasonography, and interventional radiologic procedures pertinent to patients in the intensive-care unit are reviewed.

Dissolution of cholesterol gallstones using methyl tert-butyl ether.

Symptomatic cholelithiasis affects a large segment of the population. Several nonoperative therapeutic alternatives for treatment of these gallstones have recently been developed. We present here the technical aspects and results of gallstone dissolution in 75 patients with the use of methyl tert-butyl ether (MTBE) administered via a small percutaneously placed cholecystostomy catheter. Successful stone dissolution was achieved in 69 patients. The average time required for stone dissolution was 12.4 h over an average of 2.4 days, with the success and rate of dissolution being very dependent on technique. Six patients have developed recurrent gallstones. Future efforts will focus on decreasing the labor intensity of the procedure, dealing with the noncholesterol components of gallstones, and preventing gallstone recurrence.

Low-osmolality contrast media: a current perspective.

Intravascular radiographic contrast media play a major role in diagnostic imaging. Recently, low-osmolality contrast media (LOCM) have become available in the United States. Because of their lower osmolality, these new agents cause fewer undesirable physiologic effects and fewer adverse reactions than do conventional agents after intravascular administration. Unfortunately, the cost of LOCM is substantially higher than the cost of conventional contrast media. Appropriate use of these newer, more expensive contrast agents must be based on a thorough knowledge and understanding of their chemistry, physiologic features, and relative safety. Some questions remain about these new agents. Further studies are needed to determine the nephrotoxicity of LOCM relative to that of conventional agents. In addition, LOCM have less anticoagulant capacity than do the conventional media; therefore, clotting may occur when the LOCM and blood mix in syringes and small catheters. This potential decrease in anticoagulation and its clinical implications should be further investigated. Finally, the mortality rate associated with use of LOCM needs to be determined in future studies in large numbers of patients.

Dissolution of cholesterol gallbladder stones by methyl tert-butyl ether administered by percutaneous transhepatic catheter.

We treated 75 patients with symptomatic cholesterol gallstones by dissolving the stones with methyl tert-butyl ether (MTBE) instilled into the gallbladder through a percutaneous transhepatic catheter. The MTBE was continuously infused and aspirated manually four to six times a minute, for an average of five hours per day for one to three days; the treatment was monitored by fluoroscopy. The placement of the catheter and the administration of MTBE caused few side effects or complications, and treatment did not have to be stopped in any patient for this reason. In 72 patients there was complete dissolution of stones or more than 95 percent dissolution. Among 21 patients who were completely free of stones after treatment, 4 had recurrence of stone formation 6 to 16 months later. The other 51 patients had residual debris, which spontaneously cleared completely in 15 patients within 6 to 35 months; only 7 with persisting debris have had symptoms. Five of the initial 6 patients treated, but only 1 of the next 69 patients, have required surgery during follow-up periods of 6 to 42 months. We conclude that the dissolution of gallstones by MTBE delivered through a percutaneous transhepatic catheter is a useful alternative to surgery in selected patients with symptomatic cholesterol stones. Further study will be necessary to establish the long-term effectiveness of this treatment and its appropriate role in the management of the various types of gallstones.