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Biomedical subjects

T P Maus

Publications and source records attributed to T P Maus.

18 recordsLinked to original sources

Acute pulmonary embolism: assessment of helical CT for diagnosis.

PURPOSE: To determine the sensitivity and specificity of helical computed tomography (CT) for the diagnosis of acute pulmonary embolism. MATERIALS AND METHODS: This prospective study included 47 patients who underwent pulmonary arteriography for evaluation for possible acute pulmonary embolism. Tailored helical CT and pulmonary arteriography were performed within 24 hours of each other. Each CT scan was interpreted by two chest radiologists, blinded to arteriographic results, at two institutions. CT scan interpretations were compared with findings on bilateral selective pulmonary arteriograms interpreted by two vascular radiologists at one institution. RESULTS: Fifteen (32%) of 47 patients had angiographically proved pulmonary embolism. For the readers at the first institution, helical CT had 60% sensitivity, 81% specificity, 60% positive predictive value, 81% negative predictive value, and 75% overall accuracy. For the readers at the second institution, helical CT had 53% sensitivity, 97% specificity, 89% positive predictive value, 82% negative predictive value, and 83% accuracy. CONCLUSION: Detection of pulmonary embolism with helical CT may be less accurate than previously reported. Given its high specificity but relatively low sensitivity, helical CT may not have the ideal attributes of a first-line imaging study for the diagnosis of pulmonary embolism.

Acute Disease↗

Fast CT for pulmonary embolus.

Recent technical advances in CT have led to the ability to scan a volume in a shorter period with optimal contrast opacification of blood vessels, including the pulmonary arteries. Initially, there were isolated instances of an accidental detection of a filling defect because of pulmonary embolus in the pulmonary arteries. Gradually, directed examinations were introduced to diagnose or exclude pulmonary embolus. These examinations were successful. Radiologists and clinicians now are turning to fast CT for this purpose for a variety of reasons, including the proven accuracy and reliability of the method and the relative deficiencies of traditional noninvasive methods. Accurate interpretation of CT scans for possible pulmonary embolus depends on the ability to conduct a high-quality examination and to recognize the spectrum of findings for both acute and chronic emboli. This article reviews the history of fast CT pulmonary angiography, and it presents both technical and diagnostic information germaine to the performance of this technique.

Acute Disease↗

Pulmonary embolism: diagnosis with contrast-enhanced electron-beam CT and comparison with pulmonary angiography.

PURPOSE: To determine the sensitivity and specificity of contrast material-enhanced electron-beam computed tomography (CT) in the diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: Sixty patients suspected of having PE were prospectively evaluated with pulmonary angiography and contrast-enhanced electron-beam CT. Thirty-eight patients underwent ventilation-perfusion (V-P [also known as V/Q]) scanning. The pulmonary vasculature was divided into 12 anatomic zones. CT and angiographic findings were correlated on a patient-by-patient basis and for each vascular zone. RESULTS: Both studies were negative for PE in 36 patients. Both studies were positive in 15 patients, with the site of the emboli correlating well. Prospective sensitivity of CT was 65%; specificity, 97%; positive predictive value, 94%; and negative predictive value, 82%. After review of the nine discordant cases, sensitivity and specificity approached 100% for clinically important acute PE. CT depicted central and peripheral emboli equally well. CT was more sensitive and specific than V-P scanning. CONCLUSION: Electron-beam CT is a sensitive and specific noninvasive method for the diagnosis of PE. It has the potential to replace V-P scanning as the primary screening examination for PE.

Humans↗

Popliteal artery aneurysms: the risk of nonoperative management.

To evaluate the risk of nonoperative management of popliteal artery aneurysms (PAAs), a retrospective cohort study of 106 consecutive patients (103 males and 3 females) with PAAs seen between January 1, 1980, and December 31, 1985, was performed. The mean age was 70.5 years (range 50 to 90 years). The 106 patients with 161 PAAs were followed for a mean of 6.7 years (range 3 days to 12.1 years). Follow-up was complete in 91.5% (97/106) of the patients. PAA was confirmed by ultrasonography in 124 limbs (77%), arteriography only in 7 (4.3%), and physical examination only in 32 (19.9%). Fifteen limbs presented with acute symptoms, 52 with chronic symptoms, and 94 were asymptomatic. Five of the 15 limbs with acute symptoms (33%) underwent amputation (4 primary, 1 secondary). PAAs in 23 of the 52 limbs with chronic symptoms were repaired; 2 limbs required amputation (8.7%). Twenty-seven of the 94 asymptomatic limbs were repaired initially; 1 required amputation (3.7%). The remaining 67 asymptomatic limbs were initially managed nonoperatively. Amputation was required in 3 of 67 limbs (4.4%), 1 with acute symptoms and 2 with chronic symptoms, all of which had undergone attempted repair. Symptoms (3 acute, 9 chronic) eventually developed in 12 (17.9%). At least one of three risk factors (size > 2 cm, thrombus, and poor runoff) was initially present in 11 of 12 limbs (91.7%) compared with 9 of 24 control limbs (37.5%) that remained asymptomatic (p < 0.05). Amputation rates in symptomatic patients with PAAs continues to be high. In patients with asymptomatic PAAs, aneurysm size > 2 cm, thrombus, or poor runoff predicted the development of symptoms. PAA patients with any of these factors should undergo elective repair, even asymptomatic patients who have a reasonable chance for long-term survival.

Aged↗

Diagnostic features and clinical outcome of ischemic-type biliary complications after liver transplantation.

The clinical significance and outcome of nonanastomotic strictures and dilatations involving only the biliary tree of the graft with a radiological appearance of biliary ischemia is unknown. Therefore we analyzed the grafts of 128 patients to evaluate the biochemical, radiological and histological features that prompted the diagnosis of ischemic-type biliary stricture and the clinical outcome of this complication. Ischemic-type biliary strictures were diagnosed in 25 patients (19%). Initial graft function was similar in all patients, whether or not this complication developed. Most ischemic-type biliary strictures occurred between 1 and 4 mo after orthotopic liver transplantation. However, the appearance of ischemic-type biliary stricture in the month after transplantation was predictive for a poor outcome in all six grafts with early onset of ischemic-type biliary strictures. Eighteen patients (72%) were treated with biliary stents and repeated dilatations. Long-term patency was achieved in 88% of these patients. Repeat transplantation was performed in six patients (24%); five survived. Finally, patients with ischemic-type biliary strictures spent more time in the hospital during the first year after orthotopic liver transplantation than did patients without the complication (62 +/- 27 days vs. 37 +/- 20 days; p < or = 0.001). This was due to repeated hospitalizations and a higher incidence of retransplantation. One-year graft survival was lower in patients with ischemic-type biliary strictures than in patients without ischemic-type biliary strictures (69% vs. 88%; p = 0.006). However, 1-yr patient survival was similar in the two groups (91% vs. 89%). In conclusion, early appearance of ischemic-type biliary stricture features is associated with poor graft prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

Pulmonary embolism: diagnosis with electron-beam CT.

Contrast material-enhanced electron-beam computed tomography (CT) (100-msec scan time) was performed to image the pulmonary vasculature in 86 patients, each suspected of having a pulmonary embolism (PE). Thromboembolic material was demonstrated in 39 patients; no emboli were demonstrated in 47. In 25 patients, angiographic or pathologic proof was available. There were 19 proved positive CT scans, four proved negative scans, one false-negative scan, and one false-positive scan. In the 21 patients with CT and angiographic correlation, evidence of thromboembolic disease was seen in 88 vascular zones. Fifty-three zones were positive for PE at both CT and angiography. Eighteen zones were positive for PE at angiography alone, and 17 zones were positive at CT alone. Electron-beam CT is a potentially effective noninvasive means of diagnosing PE.

Adult↗

Ischemic-type biliary complications after orthotopic liver transplantation.

Nonanastomotic biliary strictures that involve only the biliary tree of the graft occur after orthotopic liver transplantation in patients with hepatic artery thrombosis, chronic ductopenic rejection and ABO blood group incompatibility. This complication may also occur in the absence of these known risk factors. The major focus of our study was to evaluate the risk factors for nonanastomotic biliary stricturing of unknown cause after orthotopic liver transplantation. Results demonstrate that the development of biliary strictures is strongly associated with the duration of cold ischemic storage of allografts in both Euro-Collins solution and University of Wisconsin solution. Results also demonstrate that strictures are not associated with the type of biliary reconstruction, the primary liver disease, cytomegalovirus infection, allograft rejection or the presence of a positive lymphocytotoxic crossmatch. More recently, we have markedly reduced the occurrence of nonanastomotic biliary stricturing by decreasing the ischemia time of our allografts. Thus nonanastomotic biliary strictures appear to be the result of the ischemia/reperfusion-induced tissue injury associated with the harvest and implantation of allografts.

Adenosine↗

Hilar biliary strictures after liver transplantation: cholangiography and percutaneous treatment.

Nonanastomotic hilar bile duct strictures developed in 16 of 152 patients who underwent liver transplantation. The type of pretransplantation liver disease did not significantly affect the likelihood of hilar stricture formation. Possible causes of hilar biliary strictures include hepatic artery occlusion, ductopenic arteriopathic rejection, and cytomegalovirus infection; however, five of the 16 patients had hilar strictures without these complications. Hilar strictures developed within 3 months after transplantation in 11 of the 16 patients. Strictures began as a slight common hepatic duct irregularity and progressed to mucosal cast formation and later to firm strictures. Fifteen of the 16 patients underwent percutaneous stricture dilation. Of 12 patients who no longer have stents, four have had no stricture recurrence for 12-30 months. Eight patients have had to undergo retransplantation or have died. Percutaneous dilations were most likely to result in patient bile ducts if strictures developed within 3 months after transplantation and in the absence of pretransplantation primary sclerosing cholangitis, ductopenic arteriopathic rejection, cytomegalovirus infection, or hepatic artery thrombosis.

Adolescent↗

Arthrographic study of painful total hip arthroplasty: refined criteria.

The criteria for a diagnosis of loosening or infection of hip arthroplasties on arthrographic study were further refined by a retrospective review of 178 arthrograms representing 170 patients. The 97 arthroplasties that were surgically evaluated form the basis of this report. With the refined criteria, subtraction arthrography had a sensitivity of 96% and specificity of 92% for demonstrating loosening of the femoral component and a sensitivity of 97% and a specificity of 68% for demonstrating loosening of the acetabular component. Pseudocapsule size and the presence of bursae were important factors influencing arthrographic interpretation. Arthrographic findings of pseudocapsule irregularity and the presence of nonbursal cavities were suggestive of infection but were not sensitive or specific. Laboratory evaluation of aspirated material was a more reliable predictor of infection, although its sensitivity was only 71%.

Adolescent↗

Pseudobursae: a useful finding in patients with painful hip arthroplasty.

A retrospective review of 178 consecutive subtraction hip arthrograms (175 patients) was performed to evaluate the significance of cavities or bursal communications (or both) with the pseudocapsule in patients with painful hip arthroplasty. Bursae and/or communicating cavities were shown in 75 (43%) of the 175 patients. Communicating irregular cavities were noted in 12 patients (nine infected), and smooth bursae or bursalike structures were noted in 63 patients. The most frequent bursal locations were the greater trochanteric region (32/63), supraacetabular region (18/63), and iliopsoas (12/63). Three patients had multiple bursae. Six of the 18 acetabular bursae were associated with previous dislocations. Twenty-seven patients with bursae had no radiographic findings of loosening or infection. Of these 27, 12 (44%) responded to local injection of anesthetic into the bursa and were judged clinically to have bursitis. Arthrography, with aspiration from the bursae or cavities and injection of anesthetic, provides additional information regarding painful hip arthroplasty and may prevent unnecessary surgery.

Adult↗

Rat phenol sulfotransferase. Assay procedure, developmental changes, and glucocorticoid regulation.

Phenol sulfotransferase (PST) catalyzes the sulfate conjugation of phenolic monoamines and phenolic drugs. It has been difficult to measure PST activity in tissue homogenates accurately because of the presence of potent endogenous PST inhibitors. Optimal conditions were determined for the assay of rat PST in very dilute tissue homogenates. These conditions negated the effects of endogenous enzyme inhibitors. Apparent Km values for 3-methoxy-4-hydroxyphenylglycol, the sulfate acceptor substrate used, were 0.15, 0.14, and 0.02 mM for liver, kidney, and brain homogenates respectively. Apparent Km values in the same tissues for 3'phosphoadenosine-5'phosphosulfate, the sulfate donor, were 0.11, 0.07, and 0.07 microM respectively. Rat PST activity expressed per mg protein increased 6.3-fold in the liver, 6.6-fold in the brain, and did not change in the kidney between birth and 10 weeks of age. There was a 5-fold increase in kidney PST activity in both adrenalectomized and sham-operated Sprague-Dawley rats after treatment with dexamethasone (7 mumoles/kg daily for 3 days). Brain enzyme activity was unchanged and liver PST activity increased only 41% during 72 hr of daily treatment with dexamethasone. Basal enzyme activities in all three tissues were no different in adrenalectomized and sham-operated animals. The increase in rat kidney PST activity in response to dexamethasone was dose dependent, and treatment of animals with cycloheximide, a protein synthesis inhibitor, blocked the elevation of kidney PST activity after dexamethasone. Treatment of eight inbred and two outbred rats strains with dexamethasone resulted in striking increases in renal PST, smaller increases in liver PST, and no changes in brain enzyme activity in all ten strains.

Adrenalectomy↗

Management of inferior pancreaticoduodenal artery aneurysms: a 4-year, single center experience.

Inferior pancreaticoduodenal artery aneurysms are uncommon visceral artery aneurysms usually difficult to resect, and, if untreated, have a propensity to rupture with catastrophic results. We reviewed the clinical and treatment records of four patients encountered in our institution within the last 4 years. Three patients presented as bleeding emergencies from single aneurysms and were successfully treated by transcatheter embolization using coaxial technique and a variety of embolic agents. One nonemergent, asymptomatic patient had surgical resection of two inferior pancreaticoduodenal artery aneurysms due to unfavorable anatomy for embolization. Embolization therapy appears to be the treatment of choice in the emergency setting. Patients with unsuitable anatomy for embolization may still require surgical intervention.

Aneurysm↗