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R L MacCarty

Publications and source records attributed to R L MacCarty.

At least 19 recordsLinked to original sources
PubMed2001

CT colonography: single- versus multi-detector row imaging.

PURPOSE: To compare respiratory artifacts, colonic distention, and polyp detection at computed tomographic (CT) colonography by using single- and multi-detector row helical CT systems. MATERIALS AND METHODS: A total of 237 consecutive patients received subcutaneously administered glucagon and underwent prone and supine CT colonography with single-detector row CT (n = 77) and multi-detector row CT (n = 160), followed by colonoscopy. Examination results were graded for colonic distention, respiratory artifacts, and polyp depiction by two radiologists working independently. RESULTS: Suboptimal colonic distention was significantly more common with single-detector row CT and was present in at least one segment in 52% (40 of 77 patients) of examinations versus only 19% (30 of 160 patients) with multi-detector row CT (P <.001). Mild respiratory artifacts were present in 61% (47 of 77 patients) of single-detector row CT examinations versus only 16% (26 of 160 patients) of multi-detector row CT examinations (P <.001). Depiction of polyps larger than 10 mm was 89% (eight of nine polyps) for single-detector row CT and 80% (eight of 10 polyps) for multi-detector row CT (P >.05). CONCLUSION: CT colonography performed with multi-detector row CT significantly improved the demonstration of colonic distention and depicted fewer respiratory artifacts compared with single-detector row CT. No significant differences in the depiction of polyps larger than 10 mm were demonstrated between single- and multi-detector row CT for a small number of polyps. Studies with a larger prevalence of clinically important polyps are needed for further evaluation of differences in polyp detection.

Adult↗
PubMed2000

Incidental extracolonic findings at CT colonography.

PURPOSE: To determine the frequency of extracolonic findings at computed tomographic (CT) colonography and the effect of these findings on subsequent patient treatment and cost. MATERIALS AND METHODS: Conventional transverse CT colonographic scans in 264 consecutive patients were evaluated independently by two radiologists. Extracolonic findings were classified as having high, moderate, or low clinical importance. The effect of CT findings on patient treatment was assessed with chart review. The cost of additional examinations was calculated by using 1999 Medicare reimbursements. RESULTS: Thirty (11%) patients had highly important extracolonic findings, which resulted in further examinations in 18 (7%) patients, including ultrasonography in 10, CT in 13, and intravenous pyelography in one. Six patients underwent surgery because of incidentally discovered CT colonographic findings. Two patients with findings of moderate or low importance underwent additional imaging. A total of $7,324 was required for work-up for extracolonic findings (mean of an additional $28 per examination). Three extracolonic malignancies were overlooked at CT colonography. CONCLUSION: Additional work-up of extracolonic CT colonographic findings was relatively infrequent but was often worthwhile when performed for lesions classified as highly important. The evaluation of extracolonic structures at CT colonography has definite limitations with regard to solid organs but can help detect serious disease without substantially increasing the cost per patient.

Abdomen↗
PubMed2000

Optimization of CT colonography technique: prospective trial in 180 patients.

PURPOSE: To assess the added benefits of prone positioning in addition to supine positioning and oral iodinated contrast medium for help in the detection of colonic polyps at computed tomographic (CT) colonography. MATERIALS AND METHODS: CT colonography was performed in prone and supine positions in 180 patients with polyps or risk factors for colonic neoplasia. Patients were randomly assigned to receive a standard bowel preparation or a standard preparation plus oral iodinated contrast medium. One radiologist interpreted supine images alone, and another analyzed supine and prone images. All patients subsequently underwent colonoscopy. RESULTS: At colonoscopy, 121 large (> or =1-cm-diameter) polyps and 142 smaller (0.5-0.9-cm) polyps were identified. Prone positioning resulted in increased sensitivity for identification of patients with large (> or =1-cm) polyps (increase from 70% to 85%, P: =.004) and of patients with polyps 0.5 cm or larger (increase from 75% to 88%, P: <.005), with no change in specificity. Use of oral contrast medium did not significantly improve polyp detection even in the subset of patients in whom colonic fluid attenuation was markedly increased. CONCLUSION: Acquisition and review of supine and prone CT colonographic images significantly improves the ability to identify patients with polyps 0.5 cm in diameter or larger. Administration of oral iodinated contrast medium does not significantly improve polyp detection.

Colon↗
PubMed1997

Risk and significance of endoscopic/radiological evidence of recurrent Crohn's disease.

BACKGROUND & AIMS: The aim of this study was to determine the risk of endoscopic/radiological recurrence of Crohn's disease postoperatively and the long-term outcome. METHODS: A randomized placebo-controlled trial was performed to determine the effectiveness of mesalamine in preventing recurrent Crohn's disease postoperatively. Patients in the control group were examined endoscopically/radiologically before entry into and annually during the trial. Findings were classified as minimal or severe. RESULTS: There were 76 patients (49 men and 37 women; mean age, 37.1 +/- 13.2 years). Fifty (61.7%) had terminal ileal resections. Overall, 55 endoscopic/radiological recurrences were observed in 51 patients (67.1%). Expressed actuarially, the recurrence rate was 27.5% at 1 year (95% confidence interval [CI], 15.8%-37.6%), 60.8% at 2 years (95% CI, 46%-71.3%), and 77.3% at 3 years (95% CI, 62.7%-86.3%). Nineteen (37%) were symptomatic and 12 (24%) were initially asymptomatic but later became symptomatic (mean, 13.0 +/- 8.8 months), whereas 20 (39%) remained asymptomatic (mean, 16.9 +/- 17.4 months). Patients with severe endoscopic/radiological disease were significantly more likely to be or become symptomatic than those with minimal disease (23 of 32 vs. 8 of 19, respectively; P = 0.0437). CONCLUSIONS: This study suggests that postoperative endoscopic/radiological recurrences occur later than previously reported. Furthermore, many of these patients, especially with minimal disease, will remain asymptomatic.

Actuarial Analysis↗
PubMed1997

Detection of colorectal polyps with CT colography: initial assessment of sensitivity and specificity.

PURPOSE: To estimate the sensitivity and specificity of computed tomographic (CT) colography in detection of colorectal polyps and to compare these findings with those at axial CT. MATERIALS AND METHODS: In 70 consecutive patients, CT colography and colonoscopy were performed. Helical axial CT images and CT colographic images (multiplanar two- and three-dimensional endoluminal images) were evaluated separately by two radiologists blinded to results from colonoscopy and other imaging studies. Findings were compared with those at colonoscopy, which was the standard. RESULTS: The sensitivity and specificity for the two observers with CT colography averaged 75% and 90% in patients with adenomas 10 mm in diameter or larger, 66% and 63% in patients with adenomas 5 mm in diameter or greater, and 45% and 80% for patients with adenomas less than 5 mm in diameter, respectively. Sensitivity and specificity with axial CT were lower than those with CT colography (58% and 74%, respectively) in patients with adenomas 10 mm in diameter or larger. CONCLUSION: Compared with axial CT, CT colography appears to have superior sensitivity and specificity in detection of clinically important colorectal adenomas. Early performance of CT colography seems promising for detection of colorectal polyps 5 mm and larger.

Adenoma↗
PubMed1996

Barium enema: detection of colonic lesions in a community population.

OBJECTIVE: The purposes of this study were to assess the prevalence of colonic lesions detected at barium enema in a community practice, to compare the findings at barium enema between patients who are asymptomatic and have no known risk factors for colorectal cancer (screening group) and patients who have symptoms of colonic disease or have known risk factors, and to determine if a questionnaire about symptoms and risk factors is an appropriate screening tool. SUBJECTS AND METHODS: A self-administered questionnaire about colorectal symptoms and risk factors was given to 1779 patients scheduled for barium enema examination. On the basis of their responses, patients were divided into three groups: screening group (asymptomatic, without risk factors), symptomatic, and asymptomatic with risk factors. Each patient underwent a fluoroscopic barium enema. We then compared the results (number, histologic type, size of lesion(s), location in the colon, and Patient's age) and risk factors among the three groups. RESULTS: At least one lesion within the colorectum was found in 166 (9%) of 1779 patients at combined proctosigmoidoscopy and barium enema. The prevalence of lesions in the 111 patients with at least one lesion above the rectum at barium enema was 4% (32 of 738) for the screening group, 8% (38 of 476) for asymptomatic patients with risk factors, and 7% (41 of 565) for symptomatic patients (p = .015 when comparing the prevalence in the screening group with the prevalences in the other two groups). Twenty-nine percent of all colonic lesions were found in the screening group. Among the asymptomatic patients, risk factors that included a history of colorectal polyps and advanced age were associated with a significantly higher prevalence of colonic polyps found at barium enema. In the symptomatic group, if patients with histories of polyps were excluded, we were unable to identify other risk factors that led to a significantly higher prevalence of polyps. CONCLUSION: Asymptomatic patients without known risk factors have a significantly lower prevalence of colonic polyps than either symptomatic patients or patients with risk factors alone. Despite this lower prevalence, 29% of all lesions in our series were in the screening group. Assessment of risk factors through a patient questionnaire was not helpful in identifying a group of patients with a higher prevalence of lesions--except for a history of polyps. Management decisions based on a patient questionnaire should be approached with caution. When low-risk patients are denied screening examinations, a significant number of lesions will be missed.

Aged↗
PubMed1995

Abnormalities in the shape of the duodenal loop on X-ray. Associated with idiopathic antral hypomotility?

We aimed to determine if abnormalities in the shape of the duodenal loop would be useful in identifying patients with gastroduodenal dysmotility. Retrospectively, 126 consecutive patients with suspected functional abdominal symptoms who underwent upper gastrointestinal barium x-ray studies and gastrointestinal manometry were independently evaluated. Twenty-seven patients (21%) had an abnormally shaped duodenal loop (two proximal and 25 distal) by x-ray. An abnormal duodenal loop was associated with female gender but the presenting symptoms were similar in patients with normal and abnormal loops. Antral hypomotility was significantly more common in patients with distal duodenal malrotations compared to those with a normal x-ray (56% vs 27%, P < 0.01); intestinal dysmotility was not associated with the shape of the duodenal loop. The presence of an abnormally shaped duodenal loop in patients presenting with functional gastrointestinal symptoms may be a useful marker for idiopathic antral hypomotility.

Adolescent↗
PubMed1995

Single-pass CT of hepatic tumors: value of globular enhancement in distinguishing hemangiomas from hypervascular metastases.

OBJECTIVE: The purpose of this study was to evaluate the sensitivity and specificity of globular enhancement for differentiating hepatic hemangiomas from hypervascular metastases on single-pass, contrast-enhanced CT scans. Globular enhancement was defined as enhancing nodules less than 1 cm seen within a lesion. MATERIALS AND METHODS: Fifty CT examinations were retrospectively evaluated in a blinded fashion by two independent reviewers. The CT studies were done with nonhelical technique after the IV injection of 150 ml of contrast material. The series included 25 patients with histologically proven hypervascular hepatic metastases (carcinoid, islet cell carcinoma, and leiomyosarcoma) and 25 patients with clinically proven hepatic hemangiomas. Patients with hemangiomas were clinically stable for at least 2 years after the CT studies. A single lesion was isolated from the first-pass, contrast-enhanced portion of each examination; the remainder of the examination was excluded from the review to minimize reviewer bias. Each lesion was evaluated for (1) the presence or absence of globular enhancement (defined as enhancing nodules less than 1 cm seen within a lesion), (2) the density of globular enhancement relative to that of the aorta, (3) the degree of border definition (well or poorly marginated), and (4) the presence or absence of a hypodense halo. A diagnostic impression was then recorded for each lesion. RESULTS: Globular enhancement was 88% sensitive and 84-100% specific for differentiating hepatic hemangiomas from hypervascular metastases (p < .001). A mean of 62% of hemangiomas showed globular enhancement isodense relative to that of the aorta; none of the metastases showed globular, isodense enhancement. The majority of the metastases showed nonglobular enhancement (mean, 92%). The reviewers showed 84% agreement in the identification of (1) globular enhancement in hemangiomas, (2) lack of globular enhancement in metastases, and (3) globular enhancement in the combined set of all lesions. Neither the presence of a hypodense halo nor the degree of border definition was significant in distinguishing between the two groups of lesions. The reviewers showed 96% agreement in the categorization of metastases and 76% agreement in the categorization of hemangiomas. There was 86% agreement in the categorization of all lesions. Overall, reviewers diagnosed a mean of 89% of lesions correctly. A mean of 98% of metastases and a mean of 80% of hemangiomas were diagnosed correctly. CONCLUSIONS: Globular enhancement is highly sensitive (88%) and specific (84-100%) for differentiating hepatic hemangiomas from hypervascular metastases on single-pass, contrast-enhanced CT scans.

Adult↗
PubMed1992

Colorectal cancer: the case for barium enema.

Both colonoscopy and barium enema are important techniques for examining the colon for polyps and cancer. They are approximately equally sensitive in detecting polypoid lesions of 7 to 10 mm or larger. A major limitation of colonoscopy is that the cecum cannot be visualized in 10 to 36% of cases. The comparable accuracy for detecting significant lesions, greater safety, and greater cost-effectiveness of barium enema favor its use in most patients.

Barium Sulfate↗
PubMed1992

Ischemic cholangitis in hepatic allografts.

In this report, our objectives are to introduce the term "ischemic cholangitis" as an etiologic designation and to describe its manifestations. Herein we use the label "ischemic cholangitis" as a collective term for ischemic bile duct necrosis, cholangitis caused by ischemia but without necrosis, and biliary fibrosis as a manifestation of ischemic damage. The condition was observed in 12 allografts, either at the time of retransplantation (9 cases) or at autopsy (3 cases). Ischemic cholangitis involved primarily perihilar extrahepatic and intrahepatic bile ducts. The findings included duct necroses (eight cases), strictures (four cases), and cholangiectases (four cases); some of these features coexisted. In addition, complicating ascending cholangitis and cholangitic abscesses were noted in three cases. Ischemic cholangitis was caused by hepatic artery thrombosis (in nine patients) or stenosis (in one) or by occlusion of parabiliary arteries by fibrointimal proliferations, probably attributable to old thromboses (in two, in conjunction with associated foam cell arteriopathy in one). Biopsy specimens before retransplantation or autopsy were obtained in 11 patients, only 1 of whom had an infarct as direct evidence of ischemia. Nine patients had evidence of biliary obstruction or bile flow impairment; in two cases, specimens were normal or nondiagnostic relative to cholangitis. Features of cellular rejection associated with the manifestations of bile flow impairment and ischemia were noted in five cases. Thus, biopsy features that suggest biliary obstruction, with or without cellular rejection, may be a manifestation of ischemic cholangitis. We conclude that ischemic cholangitis is an important cause of cholestatic graft failure but that this type of cholangitis is difficult to diagnose because of its misleading biopsy manifestations.

Adult↗
PubMed1991

Primary sclerosing cholangitis: value of cholangiography in determining the prognosis.

We studied cholangiograms in 129 patients with primary sclerosing cholangitis (PSC) to determine if there was a correlation between any of the findings and the prognosis of the disease. The grade, length, and extent of strictures, the degree of bile duct dilatation, and the distribution of lesions were evaluated. Survival curves were generated to test the association of these radiologic signs with subsequent survival. High-grade intrahepatic duct strictures (greater than 75% narrowing) were associated with a 19% decrease in 3-year survival (p = .05) compared with lower-grade strictures. Diffuse intrahepatic strictures (involving greater than 25% of the ducts) were associated with a 16% decrease in 3-year survival (p = .012) compared with localized strictures. Statistically insignificant (p greater than .05) but measurable decreases in survival were observed with high-grade extrahepatic duct strictures, diffuse involvement of the extrahepatic ducts, long confluent strictures anywhere in the biliary tree, and marked dilatation of the intrahepatic ducts. In general, intrahepatic duct disease was found to have greater prognostic significance than extrahepatic duct disease. High-grade strictures and diffuse strictures of the intrahepatic ducts were found to be indicators of a poor prognosis in PSC and were more predictive of a poor prognosis than was extrahepatic duct disease.

Adult↗
PubMed1990

GR 38032F (ondansetron), a selective 5HT3 receptor antagonist, slows colonic transit in healthy man.

The newly recognized class of 5-hydroxytryptamine receptors (5HT3) may be involved in the induction of nausea, since their pharmacological antagonists are effective against emesis induced by chemotherapy. 5HT3 receptors are present on enteric neurons, and 5HT3 blockers may produce mild constipation; we thus hypothesized that 5HT3 receptors would modulate colonic motility. To determine if GR 38032F, a selective 5HT3 antagonist known to have antiemetic effects, influences colonic transit in health, a randomized, double-blind, placebo-controlled crossover study was performed. Using a radiopaque marker technique, colonic transit was quantified in 39 healthy volunteers (19 men, 20 nonpregnant women) 18-70 years of age. On a standard 25-g fiber diet, 16 mg of GR 38032F was given orally thrice daily. Gastrointestinal peptides (peptide YY, human pancreatic polypeptide, neurotensin, motilin, gastrin-cholecystokinin, substance P) were also measured in plasma fasting and postprandially. Mean total colonic transit time on placebo was 27.8 hr, while on GR 38032F it was 39.1 hr (P less than 0.0005). Transit times through the left colon (P less than 0.0005) and rectosigmoid (P less than 0.05) were prolonged by the drug, but right colonic transit was not significantly altered. Transit times did not correlate with age or gender, but subjects with shorter transit times were significantly more affected than were those with longer transit times. The peak release of peptide YY was minimally decreased following GR 38032F (P less than 0.01), but the peak and integrated postprandial responses of human pancreatic polypeptide, neurotensin, motilin, gastrin-cholecystokinin, and substance P were not significantly altered by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Barium studies in diffuse eosinophilic gastroenteritis.

We report the findings on barium examinations from 20 patients with eosinophilic gastroenteritis. Thickening of mucosal folds in the stomach (seven cases), small intestine (four patients), or both (two cases) was the most common finding. Nodular fold enlargement was present in the stomach in three cases and in the small intestine in four cases. One patient had discrete antral polyps. Multiple gastric erosions, to our knowledge not previously reported in eosinophilic gastroenteritis, were seen in two patients. Although the stomach and small bowel are most commonly affected, any portion of the gastrointestinal tract may be involved.

Adult↗
PubMed1990

Advances in primary sclerosing cholangitis.

Primary sclerosing cholangitis is an increasingly recognized chronic cholestatic liver disease. It frequently occurs in association with chronic ulcerative colitis and is characterized by inflammation and fibrosis of the intrahepatic and extrahepatic bile ducts. The cause is unknown, although many mechanisms have been considered, including infectious, toxic, and immunologic. The prognosis varies. No adequate treatment exists, although a number of potential treatments have been evaluated in uncontrolled trials, and the results of controlled trials have only recently been reported. Liver transplantation has recently been shown to be an effective treatment for end-stage disease. These various advances in our understanding of primary sclerosing cholangitis are reviewed.

Cholangitis, Sclerosing↗
PubMed1990

Patients with asymptomatic primary sclerosing cholangitis frequently have progressive disease.

We identified and analyzed 45 patients with asymptomatic primary sclerosing cholangitis to better understand the natural history of this disease. Disease progression was monitored at regular intervals for the development of symptoms and physical signs as well as changes in liver biochemistry, cholangiography, and liver histology. During a median follow-up of 75.2 mo, 34 patients (76%) had evidence of disease progression. Fourteen patients (31%) developed liver failure which resulted in death or referral for liver transplantation. For patients with primary sclerosing cholangitis, survival curves computed using the Kaplan-Meier method were significantly worse than expected when compared to age-, sex-, and race-specific survival rates for the United States north central population (p less than 0.001). These findings indicate that primary sclerosing cholangitis is generally a progressive disease with considerable morbidity and mortality even when detected before the onset of symptoms.

Adult↗
PubMed1989

Primary sclerosing cholangitis: natural history, prognostic factors and survival analysis.

The natural history of primary sclerosing cholangitis was assessed in 174 patients; 37 were asymptomatic and 137 had symptoms related to underlying liver disease. At the time of diagnosis, the mean age was 39.9 years, 66% of the primary sclerosing cholangitis patients were male and 71% had associated inflammatory bowel disease, most commonly chronic ulcerative colitis. Long-term follow-up (mean: 6.0 years; range: 2.7 to 15.5 years) was available in all patients. During follow-up, 59 (34%) of the patients died: 55 in the symptomatic group and four in the asymptomatic group. Median survival from the time of diagnosis of primary sclerosing cholangitis at the Mayo Clinic was 11.9 years. Survival in the asymptomatic group was significantly decreased compared with that in a control population matched for age, race and sex. Multivariate analysis (Cox proportional hazards regression modeling) revealed that age, serum bilirubin concentration, blood hemoglobin concentration, presence or absence of inflammatory bowel disease and histologic stage on liver biopsy were independent predictors of high risk of dying. The development of a multivariate statistical survival model is a major step in identifying individual primary sclerosing cholangitis patients at low, moderate and high risk of dying. Such models will be useful for stratifying patients in therapeutic trials, in patient counseling and in patient selection and timing of liver transplantation.

Adult↗