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Biomedical subjects

J A Brink

Publications and source records attributed to J A Brink.

At least 19 recordsLinked to original sources
PubMed1992

Spiral CT: decreased spatial resolution in vivo due to broadening of section-sensitivity profile.

Comparable conventional and spiral computed tomographic (CT) scanning protocols for transaxial (n = 30) and multiplanar reformation (MPR) (n = 15) imaging were performed to image the adrenal gland and the upper pole of the right kidney in the same patient, without use of intravenously administered contrast media. The sharpness of soft-tissue-fat interfaces oriented in the transverse (xy) and longitudinal (z) directions was measured as the maximum and full width at half maximum (FWHM) of the edge attenuation profile first derivative. Edge sharpness was qualitatively assessed by three blinded reviewers, who used a four-point scale. In vivo transaxial CT studies showed that the conventional scans produced slightly sharper edges than the spiral scans (mean difference of spiral and conventional FWHM = 0.30 mm [P < .05] [in z direction] and 0.21 mm [P < .05] [in xy direction]). In vivo MPR studies showed that interfaces in the xy plane were significantly less sharp with spiral scanning, whereas interfaces in the z direction were equivalent for conventional and spiral scanning (mean difference of spiral and conventional FWHM = 0.03 mm [P > .05] [in z direction] and 1.19 mm [P < .05] [in xy direction]). Significant respiratory misregistration was present on seven of 15 (47%) conventional MPR scans and on no spiral MPR scans.

Adipose Tissue↗
PubMed1992

Sclerotherapy of malignant pleural effusion through sonographically placed small-bore catheters.

Pleural sclerosis after drainage with a small-bore catheter was performed in 21 patients with malignant pleural effusions. Intrapleural catheters 7- to 24-French in size were placed by using sonographic guidance. Tetracycline (18 patients) and bleomycin (four patients) were used as sclerosing agents (one patient had both). Clinical and radiologic follow-up was available on all patients until they died (range, 2 weeks to 25 months; mean, 3.6 months). Pleural sclerosis was successful in 15 (71%) of 21 patients. Two patients in whom pleurodesis failed had pleural sclerosis repeated, with one success and one failure. All of the failures were in patients in whom the amount of chest-tube drainage was more than 100 ml/day. Pleurodesis with tetracycline was painful in six patients; no pain was associated with use of bleomycin. Small pneumothoraces developed in four patients at the time of chest-tube placement, without consequence. A superimposed infection that developed in a patient having continuous drainage of pleural fluid was successfully treated with antibiotics. Pleural sclerotherapy can be performed through sonographically placed small-bore catheters with results comparable to those seen with large-bore, surgically placed catheters.

Adult↗
PubMed1991

Malignant small bowel obstruction and ascites: not a contraindication to percutaneous gastrostomy.

Percutaneous gastrostomy (PG) with gastropexy was performed for relief of malignant small bowel obstruction in 12 patients with extensive ascites. Abdominal paracentesis was performed before PG in nine patients and after PG in one patient. Gastrostomy catheters were inserted without complication in all patients. Clinical follow up revealed that pericatheter leakage of ascitic fluid and skin excoriation occurred only in the three patients who did not have paracentesis performed before PG. No dislodgement of gastrostomy catheters occurred but mild peritonitis was noted in one patient. Our experience suggests that although in the past extensive ascites was a relative contraindication for PG, these patients can now be successfully treated with a combination of ultrasound-guided paracentesis to reduce pericatheter leakage of ascitic fluid, and gastropexy to prevent catheter dislodgement.

Abdomen↗
PubMed1991

Percutaneous contact dissolution of gallstones: complexity of radiologic care.

The clinical and technical considerations for successful gallstone dissolution with methyl tert-butyl ether (MTBE) are often underestimated. Patients are selected for MTBE therapy on the basis of a functioning gallbladder without evidence of acute inflammation or calcified stones at plain radiography. A transhepatic route is favored for percutaneous insertion of the cholecystostomy catheter because of the theoretic reduced frequency of bile leakage. MTBE is delivered manually through the catheter in a closed system, with dissolution times of 4-16 hours. After MTBE dissolution, residual debris in the gallbladder is present at follow-up sonography in up to 75% of patients. The high frequency of residual debris, the potential for stone recurrence, and the labor-intensive nature of MTBE therapy make its future uncertain, especially with the advent of laparoscopic cholecystectomy.

Cholelithiasis↗
PubMed1991

Optimal technique for detection of gallstones at injection cholecystography: in vitro analysis.

Injection cholecystography is often employed during invasive gallbladder procedures to determine the number of gallstones that are present. The authors undertook this study to define the optimal radiographic technique for performance of injection cholecystography. Condoms filled with 100 mL of contrast medium at four different iodine concentrations (30%, 15%, 7.5%, and 3.8% [wt/vol]) and containing up to five 4-mm-thick gallstones or a single 10-mm-thick gallstone were radiographed in a 20-cm-deep water bath by using four kilovolt peak settings (70, 80, 90, and 100 kVp). Images were read by three radiologists who were blinded to the radiographic technique. significantly (P less than .05) improved Decreasing iodine concentration significantly (P less than .05) improved detection of 4-mm-thick gallstones at a constant kilovolt peak setting. However, increasing the kilovolt peak setting while using the same concentration of contrast medium had no statistically significant influence on gallstone detectability, although radiologists did indicate a preference for the high-kilovolt peak technique. Results of the authors' experiments showed that for detection of small gallstones at injection cholecystography, use of a low-concentration contrast medium and a high kilovolt peak setting is the recommended radiographic technique.

Cholecystography↗
PubMed1991

Importance of daily rounds by the radiologist after interventional procedures of the abdomen and chest.

A prospective study was performed to evaluate the clinical utility of daily rounds by the radiologist for patients with indwelling catheters in the chest and abdomen, placed during interventional radiologic procedures. The 7-week evaluation included documentation of the number of patients seen, time spent with each per day, number of problems identified, management of these problems, and consultations for new cases generated by interaction with other staff. During the 268 visits to 37 patients, 59 catheter-related problems were identified; 17 (29%) required further intervention in the radiology department, and 42 (71%) were managed at the patient's bedside. Of the patients who were followed up, 22 (59%) had some catheter-related problem identified during their hospital stay. Daily rounds by the radiologist are an essential component of patient care after catheter-related interventional procedures and should be made by those who perform and understand the procedures.

Catheterization↗
PubMed1991

Treatment of critically ill patients with sepsis of unknown cause: value of percutaneous cholecystostomy.

Because of the difficulty in diagnosing acute cholecystitis in critically ill patients with severe intercurrent illness by clinical and imaging methods or percutaneous aspiration of the gallbladder, a trial of percutaneous cholecystostomy was performed in 24 patients in the intensive-care unit with persistent, unexplained sepsis after a complete clinical, laboratory, and radiologic search showed no alternative source of infection. Persistent high fevers, despite antibiotic therapy, were present in all patients, with elevated WBC count in 18 patients, vague abdominal tenderness in 11, and septic shock requiring vasopressors in 15. Sonographically, all patients had distended, spherical gallbladders, six had gallstones, eight had wall thickening, three had pericholecystic fluid, and four had Murphy's sign. All patients were seen by a senior abdominal surgeon, who agreed to a trial of percutaneous cholecystostomy. Fourteen patients (58%) responded to percutaneous cholecystostomy, as evidenced by a decrease in WBC count, defervescence, and the ability to be weaned off vasopressors. Bile cultures were positive in four patients. Ten patients (42%) did not respond to percutaneous cholecystostomy; five eventually died of unrelated causes. A respiratory source of infection was eventually found in three of these 10 patients, with no proved source of infection in the remainder. No complications related to catheter insertion occurred in this group of patients. Bile leaks occurred in two patients when the percutaneous cholecystostomy catheter was removed, but without serious consequence. Our experience suggests that a lower threshold for performing percutaneous cholecystostomy in this difficult clinical subset of patients is worthwhile.

Acute Disease↗
PubMed1990

Nonsurgical treatment of cholelithiasis. An analysis of clinical opportunity.

This article examines the potential impact of recently developed nonsurgical treatments for gallstones on patient care and resource utilization. Using epidemiological and efficacy data from the literature and current patient selection criteria, the authors evaluate UDCA, extracorporeal shock-wave lithotripsy, and direct instillation of methyltertbutyl ether in terms of short-term clinical results, health policy, and economic implications.

Algorithms↗
PubMed1990

Gallstone fragmentation with contact electrohydraulic lithotripsy: in vitro study of physical and technical factors.

To identify physical and technical factors that have an effect on fragmentation, the authors performed in vitro contact electrohydraulic lithotripsy (EHL) on gallstones 10 mm or larger in size. Of 122 gallstones, 113 (93%) could be fragmented with 1-46 pulses from a 3-F electrode (average, 10 pulses). Only 12 of the 113 stones could be fragmented with a single spark. Of the nine stones that did not fragment with 50 pulses from a 3-F electrode, four were larger than 30 mm in diameter, and five were seen at radiography to be heavily calcified; all of these stones were fragmented with five or fewer pulses from a 9-F electrode. Stone capture in a wire basket facilitated fragmentation of gallstones of all sizes, but particularly those stones 15 mm or larger. Contact EHL could be performed as well in a 1:1 dilute diatrizoate irrigating solution as in 1:6 normal saline. A significantly greater number of pulses was required to fragment gallstones 15 mm in diameter or larger compared with stones smaller than 15 mm (P less than .01). In addition, stones 15 mm or smaller had a greater tendency to fragment into "gravel" (ie, fragments measuring 2 mm or less), while EHL of stones larger than 15 mm produced larger, discrete fragments of approximately equal size (P less than .05). EHL of heavily calcified gallstones required a significantly greater number of pulses than EHL of less calcified or noncalcified stones (P less than .002).

Cholelithiasis↗
PubMed1990

Simulation of gallstone fragments by cavitation bubbles during extracorporeal shock wave lithotripsy: physical basis and in vitro demonstration.

During extracorporeal shock wave lithotripsy of gallstones, sonography often shows a swirling pattern of echogenic foci shortly after the application of shock waves. This effect has been thought to represent gallstone fragments in suspension. However, evidence suggests that this finding is in part due to cavitation, a physical phenomenon associated with the formation or movement of gas bubbles in the fluid-filled gallbladder. Condoms filled with degassed water and five human bile specimens were positioned in the focus of an MPL 9000 lithotriptor (Dornier Medical Systems, Munich). A solitary nonradiopaque gallstone was then added to a bile-filled condom, and the sonographic pattern was observed before and after fragmentation. The mean clearance time of the cavitation bubbles was 4 seconds for degassed water and 22 seconds for human bile. Gallstone fragments were distinguished from cavitation bubbles by their prolonged settling time (up to 30 minutes) along the dependent gallbladder wall.

Bile↗
PubMed1990

Occlusion of biliary endoprostheses: presentation and management.

A retrospective review of 20 cases of endoprosthesis occlusion in 17 patients was performed. The average length of stent patency before occlusion was 3.7 months. Clinical manifestations included one or a combination of the following: cholangitis (n = 17), jaundice (n = 9), and leakage of bile or purulent material from the percutaneous insertion site (n = 6). Eighteen of 20 episodes of endoprosthesis occlusion were successfully managed with normalization of biochemical parameters and alleviation of clinical manifestations. No therapy was attempted in two episodes of stent occlusion due to widespread metastatic disease. All 17 patients received intravenous fluid replacement and broad-spectrum antibiotic therapy. This was sufficient therapy to relieve symptoms in two cases of occlusion. Occluded stents were removed in the other 16 patients by means of radiologic (n = 10) or endoscopic (n = 6) methods. After the acute septic episode had subsided (2-5 days; mean, 3 days), new endoprostheses were percutaneously inserted in 10 cases of occlusion, long-term internal-external catheters were placed in five, and surgical bypass was performed in one. The authors conclude that endoprosthesis occlusion should not be considered a terminal event in patients with malignant biliary disease.

Aged↗
PubMed1990

Percutaneous balloon dilatation of benign biliary strictures.

Percutaneous biliary dilatation is an effective alternative to surgical management of benign biliary strictures that has low morbidity and no reported mortality. Reported success rates for this procedure range from 40% to 90% depending on the size of the series, the type of patient being treated, and the length of follow-up period. The procedure is done in the fluoroscopy suite with an angioplasty balloon catheter. Transhepatic access is most common, but the procedure may be done via existing T-tube tracts or specially created jejunal loops. As the frequency of radical liver surgery such as liver transplant and radical trisegmentectomy rises, so too, the rate of biliary stricture is likely to rise, making percutaneous balloon dilatation an increasingly important tool in the interventional radiologist's armamentarium.

Catheterization↗
PubMed1989

New universal precaution aspiration tray.

A new tray has been designed for use during procedures involving needles and other sharp objects. The tray includes a foam adhesive pad, marked into 10 sections, into which the sharp objects can be placed point first. After the procedure, the objects can be safely withdrawn by their handles and then discarded. The tray has been used in more than 250 procedures.

Accident Prevention↗
PubMed1989

The sonographic diagnosis of acute gangrenous cholecystitis: importance of the Murphy sign.

The sonographic Murphy sign is defined as the presence of maximal tenderness elicited by direct pressure of the transducer over a sonographically localized gallbladder. The reported prevalence of this sign is more than 95% in patients with acute cholecystitis. In this series of 18 patients with pathologically proved gangrenous cholecystitis, the sonographic Murphy sign was positive in only six (33%). Clinical examination showed a positive Murphy sign in eight patients (44%), diffuse abdominal pain in nine patients (50%), and no pain in one patient (6%). Other sonographic findings included pericholecystic fluid (10), thickening of the gallbladder wall (10), and a dilated gallbladder (five). Our experience suggests that the absence of the Murphy sign increases the possibility of gangrenous cholecystitis in patients with abdominal pain and sonographic findings of cholecystitis.

Abdomen↗
PubMed1989

Routine sonographic techniques fail to quantify gallstone size and number: a retrospective study of 111 surgically proved cases.

We analyzed sonographic images retrospectively to determine their value in quantifying gallstone size and number in 111 surgically proved stone-containing gallbladders for which routine preoperative sonograms were available. The number and size of of stones found on pathologic examination were correlated with the results of image analysis. In patients with more than one stone, observable size differences were recorded if the smallest stone diameter was less than 50% of the largest stone diameter. Estimates of gallstone size and number from preoperative sonograms were correct in only 23 (21%) of 111 cases. Stone size and number were overestimated as often as they were underestimated. Stones of a uniform size were recognized correctly in 59 (92%) of 64 cases. Stones of two different sizes were correctly identified in only 14 (30%) of 47 cases; the second, smaller stones were missed in 26 (79%) of 33 cases. These findings indicate poor sonographic characterization of gallbladder contents when imaging studies are performed solely to determine the presence or absence of gallstones.

Cholelithiasis↗
PubMed1988

Physical characteristics of gallstones removed at cholecystectomy: implications for extracorporeal shock-wave lithotripsy.

The criteria by which patients are selected for new, nonsurgical forms of gallstone therapy will influence the use of these techniques. We estimated the number of patients with gallbladder stones who are potentially suitable for extracorporeal shock-wave lithotripsy according to the current Food and Drug Administration protocol for the United States trials of the Dornier gallbladder lithotriptor. Exclusion criteria include patients with (1) more than three stones, (2) stones less than 0.5 cm or more than 3.0 cm in diameter, (3) radiopaque stones, and (4) a nonfunctioning gallbladder. The gallbladder contents in 100 consecutive patients undergoing cholecystectomy were analyzed according to the number, size, and calcium content of the stones as determined by specimen radiographs. Because none of these patients underwent preoperative oral cholecystography, an estimated percentage of functioning gallbladders was taken from the literature. Preoperative symptoms were not considered in determining a patient's eligibility for gallbladder lithotripsy. On the basis of these criteria, we estimated that 85% of our surgical patients would have been excluded from extracorporeal shock-wave lithotripsy according to the current Food and Drug Administration protocol for the Dornier gallbladder lithotriptor.

Calcium↗