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Genevieve L Bennett

Publications and source records attributed to Genevieve L Bennett.

5 recordsLinked to original sources
PubMed2002

Computed tomography diagnosis utilizing compressed image data: an ROC analysis using acute appendicitis as a model.

Using receiver-operating characteristic (ROC) methodology, the ability to diagnose acute appendicitis with computed tomography (CT) images displayed at varying levels of lossy compression was evaluated. Nine sequential images over the ileocecal region were obtained from 53 consecutive patients with right lower quadrant pain who were clinically suspected to have acute appendicitis. Thirty were proven surgically to have acute appendicitis, alternative diagnoses confirmed in 23. The image sets were subjected to a lossy wavelet-based compression algorithm "Embedded Predictive Wavelet Image Coder" (EPWIC). Compression levels were: none, 8:1, 16:1, and 24:1, resulting in 4 sets of images per patient. Image sets were randomized and evaluated separately by 4 body radiologists on a 1,024 x 768-pixel SVGA color PC monitor in 512 x 512 format. The readers were aware of the clinical suspicion of appendicitis but were unaware of the positive fraction of cases. Individual and combined reader ROC and c2 analyses of sensitivity, specificity, and accuracy were determined. For all readers, sensitivity decreases at 16:1 and 24:1 levels (P <0.01, P <0.001, respectively). Accuracy decreased at 24:1 levels (P <0.01). Specificity was unaffected. By ROC analysis there was statistically significantly decreased area under the curve at 24:1 levels (P <0.02) as compared with uncompressed images. Finite levels of lossy wavelet compression may be applied to CT images without compromising diagnostic performance.

Acute Disease↗
PubMed2002

CT findings in acute gangrenous cholecystitis.

OBJECTIVE: The purpose of this study was to determine the CT findings in acute gangrenous cholecystitis. MATERIALS AND METHODS: Four observers retrospectively reviewed CT scans in 75 patients (23 with acute gangrenous cholecystitis, 25 with acute non-gangrenous cholecystitis, and 27 without cholecystitis). The following findings were evaluated: distention, mural thickening, wall enhancement, irregular wall, wall striation, intraluminal membranes, pericholecystic inflammation, gallstones, pericholecystic fluid, enhancement of liver parenchyma, pericholecystic abscess, and gas in the wall or lumen. Sensitivity and specificity of CT for gangrenous cholecystitis and for each finding were calculated. Two reviewers in consensus measured gallbladder dimension and wall thickness. Logistic regression models were used to predict gangrenous versus non-gangrenous cholecystitis. RESULTS: Sensitivity, specificity, and accuracy of CT for acute cholecystitis were 91.7%, 99.1%, and 94.3%, respectively, and for acute gangrenous cholecystitis were 29.3%, 96.0%, and 64.1%, respectively. Findings with the highest specificity for gangrenous cholecystitis were gas in the wall or lumen (100%), intraluminal membranes (99.5%), irregular or absent wall (97.6%), and abscess (96.6%). The difference between the mean gallbladder wall thickness and the short-axis dimension for the two groups with cholecystitis was statistically significant. In three patients with gangrenous cholecystitis, no mural enhancement was seen. Pericholecystic fluid also achieved statistical significance for the diagnosis of gangrene. Multivariate logistic regression analysis showed that the overall accuracy of CT for gangrenous cholecystitis was 86.7%. CONCLUSION: CT findings most specific for acute gangrenous cholecystitis are gas in the wall or lumen, intraluminal membranes, irregular wall, and pericholecystic abscess. Gangrenous cholecystitis is associated with a lack of mural enhancement, pericholecystic fluid, and a greater degree of gallbladder distention and wall thickening.

Acute Disease↗
PubMed2002

Sonographic detection of hepatocellular carcinoma and dysplastic nodules in cirrhosis: correlation of pretransplantation sonography and liver explant pathology in 200 patients.

OBJECTIVE: The objective of this study was to determine the sensitivity and specificity of sonography as an aid in detecting hepatocellular carcinomas and dysplastic nodules using explantation correlation in patients with cirrhosis and no known hepatocellular carcinomas. MATERIALS AND METHODS: The sonography reports of 200 patients with cirrhosis who underwent sonography and then underwent liver transplantation within 90 days were retrospectively reviewed for focal solid liver lesions. All focal solid masses detected on sonography were considered possible hepatocellular carcinomas. The sonographic findings were compared with thin-section explanted liver pathologic results. RESULTS: Twenty-seven patients (13.5%) had hepatocellular carcinoma at explantation, including four patients with diffuse, multifocal tumors. Eight of the 39 lesions were detected on sonography for a patient sensitivity of 29.6% and a lesion sensitivity of 20.5%. Sonography revealed three (75%) of four hepatocellular carcinomas larger than 5 cm in diameter, one (50%) of two hepatocellular carcinomas with diameters of 3.1-5.0 cm, one (20%) of five hepatocellular carcinomas with diameters of 2.1-3.0 cm, three (13.6%) of 22 hepatocellular carcinomas with diameters of 1-2 cm, and no lesions with diameters smaller than 1 cm. Forty-two patients (21%) had a total of 126 dysplastic nodules including two patients with innumerable lesions. Sonography depicted only two dysplastic nodules, for a patient sensitivity of 4.8% and a lesion sensitivity of 1.6%. The overall specificity of sonography for either hepatocellular carcinomas or dysplastic nodules was 96%. CONCLUSION: Sonography has low sensitivity but high specificity in revealing hepatocellular carcinomas and dysplastic nodules in patients with a cirrhotic liver requiring liver transplantation. In these patients, sonography should not be the sole imaging modality used for lesion detection before transplantation.

Adult↗
PubMedDate not supplied

Gynecologic causes of acute pelvic pain: spectrum of CT findings.

Although ultrasound (US) is the primary imaging modality of choice in the radiologic evaluation of the female patient with acute pelvic pain, the role of computed tomography (CT) in the evaluation of abdominal and pelvic pain continues to expand. CT may be performed if a gynecologic disorder is not initially suspected, if US findings are equivocal, or if the abnormality extends beyond the field of view achievable with the endovaginal probe and further characterization of pelvic disease is required. Many gynecologic disorders that cause acute pelvic pain (eg, uterine disorders, ovarian disorders, endometriosis, pelvic inflammatory disease, postoperative or postpartum complications) demonstrate characteristic CT findings. Familiarity with these CT appearances is important: It will allow the radiologist to guide appropriate treatment of affected patients and may eliminate the need for further imaging evaluation.

Acute Disease↗