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Jeff L Fidler

Publications and source records attributed to Jeff L Fidler.

12 recordsLinked to original sources
PubMed2006

Active Crohn disease: CT findings and interobserver agreement for enteric phase CT enterography.

PURPOSE: To retrospectively evaluate small-bowel enhancement characteristics and the sensitivity, specificity, and interobserver agreement of computed tomographic (CT) findings by using histologic and endoscopic results as a reference standard in patients undergoing enteric phase CT enterography. MATERIALS AND METHODS: The institutional review board approved this retrospective HIPAA-compliant study, which included patients who consented to having their medical records used for research purposes. Enteric phase CT enterographic and ileoscopic findings with or without ileal histologic results were examined in 42 patients (24 women, 18 men). Enteric phase CT enterography was performed after 150 mL of intravenous contrast material was administered at 4 mL/sec, with a 45-second delay. Mural attenuation was measured in the distended and collapsed jejunal and ileal loops and in the terminal ileum. Two radiologists examined CT images for findings of Crohn disease. Mural attenuation for different bowel loops was compared by using a Student t test, with kappa statistics used to measure interobserver agreement and Pearson correleation coefficients used to compare visual and quantitative measures. RESULTS: Distended jejunal loops had significantly greater attenuation than distended ileal loops (113 HU vs 72 HU; P < .001). Attenuation of collapsed jejunal (134 HU) and ileal (108 HU) loops was greater than that of distended jejunal and ileal loops (P < .001). Terminal ileal enhancement was the most sensitive visual CT finding of Crohn disease for both radiologists. Mural thickening demonstrated the greatest interobserver agreement (kappa = 0.83). Visual enhancement and quantitative mural attenuation were significantly correlated (P < .003). CONCLUSION: At enteric phase CT enterography, jejunal attenuation is greater than ileal attenuation and collapsed bowel loops demonstrate greater attenuation than distended bowel loops. Mural hyperenhancement and increased mural thickness are the most sensitive CT findings of active Crohn disease.

Adult↗
PubMed2006

Crohn Disease: mural attenuation and thickness at contrast-enhanced CT Enterography--correlation with endoscopic and histologic findings of inflammation.

PURPOSE: To determine retrospectively if quantitative measures of small-bowel mural attenuation and thickness at computed tomographic (CT) enterography correlate with endoscopic and histologic findings of small-bowel inflammation and to estimate the performance of these measures in predicting inflammatory Crohn disease. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study, which was conducted with patient informed consent. CT enterography data in 96 patients (31 male patients and 65 female patients) who underwent ileoscopy with or without biopsy were examined for CT signs of active Crohn disease. The most highly enhancing segment of terminal ileum and a normal-appearing ileal loop were identified. After it was confirmed that semiautomated software could accurately measure mural attenuation and thickness, the selected terminal ileal and normal-appearing (control) ileal loops were examined (20 automated measurements at each location) to quantify mural attenuation and wall thickness. Results were compared with endoscopy and histology reports by using logistic regression analysis and receiver operating characteristic curves. RESULTS: Quantitative measures of terminal ileal mural attenuation and wall thickness correlated significantly with active Crohn disease (P < .001). Small-bowel wall thickness was not a significant factor after attenuation was taken into account. A threshold attenuation value with a sensitivity of 90% (18 of 20) for definite Crohn disease (compared with a sensitivity of 80% [16 of 20] for radiologist assessment) was selected. In patients who underwent ileal biopsy, threshold attenuation had a sensitivity identical to that of ileoscopy (81% [26 of 32]; 95% confidence interval: 64%, 93%) in predicting histologic inflammation. CONCLUSION: Quantitative measures of mural attenuation and wall thickness at CT enterography correlate highly with ileoscopic and histologic findings of inflammatory Crohn disease. Quantitative measures of mural attenuation are sensitive markers of small bowel inflammation.

Adolescent↗
PubMed2006

MR elastography of the liver: preliminary results.

PURPOSE: To develop a method for measuring liver stiffness with magnetic resonance (MR) elastography and to prospectively test this technique in healthy volunteers and patients with liver fibrosis. MATERIALS AND METHODS: This HIPAA-compliant study was approved by an institutional review board, and informed consent was obtained from each subject. First, to determine the feasibility of applying shear waves to the liver, a pneumatic acoustic wave generator was developed and tested by using a tissue-simulating gel phantom with ribs on one side and without ribs on the other. The effect of interposed ribs on stiffness measurements was tested. Then, liver stiffness was measured with MR elastography in 12 healthy volunteers (eight men, four women; mean age, 26.7 years; age range, 19-39 years) by using the subcostal approach and the transcostal approach and in 12 patients with chronic liver disease (six men, six women; mean age, 50.5 years; age range, 36-60 years) by using the transcostal approach. Various statistical analyses were performed to assess all measurements. RESULTS: Ex vivo, interposed ribs reduced shear wave amplitude but did not hinder stiffness measurements. In volunteers, the transcostal approach surprisingly yielded better shear waves in the liver than did the subcostal approach. The mean liver shear stiffness was significantly lower in volunteers (mean, 2.0 kPa +/- 0.3 [standard deviation]) than it was in patients with liver fibrosis (mean, 5.6 kPa +/- 5.0; median, 3.7 kPa; range, 2.7-19.2 kPa; P < .001). CONCLUSION: MR elastography of the liver is feasible and shows promise as a quantitative method for noninvasive assessment of liver fibrosis.

Adult↗
PubMed2006

CT of small-bowel ischemia associated with obstruction in emergency department patients: diagnostic performance evaluation.

PURPOSE: To retrospectively evaluate the diagnostic performance of computed tomography (CT) for detection of small-bowel ischemia in emergency department patients with abdominal pain and to compare the prospective interpretation with a retrospective interpretation by using surgical or pathologic findings as the reference standard. MATERIALS AND METHODS: The HIPAA-compliant study was approved by the institutional review board, and patients consented to research authorization. Sixty patients (61 examinations) (25 male, 35 female patients; median age, 67 years; range, 0.9-89.7 years) with acute abdominal pain underwent immediate abdominal and pelvic CT and subsequent surgery of the small bowel within 7 days of CT. Prospective radiologic reports were reviewed for diagnosis of small-bowel obstruction and ischemia. Two gastrointestinal radiologists performed blinded, independent, retrospective review of the CT studies with no clinical data other than presence of acute abdominal pain. The reviewers categorized CT signs of obstruction and ischemia and estimated diagnostic certainty. Discordant findings were resolved by consensus review by a third gastrointestinal radiologist. CT interpretations were compared with prospective interpretations and surgical or pathologic findings. Sensitivity and specificity estimates with confidence intervals were calculated. Fisher exact and chi2 tests were used to assess associations between CT signs and the diagnosis of ischemia; kappa statistics were used to estimate agreement between readers. RESULTS: In 27 (44%) of 61 CT studies, small-bowel ischemia was surgically or pathologically confirmed. Sensitivity and specificity for the diagnosis of ischemia were, respectively, 14.8% and 94.1% for prospective interpretations, 29.6% and 91.2% for reader 1, 40.7% and 85.3% for reader 2, and 51.9% and 88.2% for the consensus review. Decreased segmental enhancement was the most specific sign for small-bowel ischemia (P = .001), and its recognition would have improved the diagnostic performance of all readers. There was a significant association of the small-bowel feces sign with the presence of small-bowel ischemia (P = .046). CONCLUSION: Diagnostic performance assessment of CT for the diagnosis of small-bowel ischemia revealed poor prospective interpretation sensitivity.

Abdominal Pain↗
PubMed2005

Nonradiologists as second readers for intraluminal findings at CT colonography.

RATIONALE AND OBJECTIVES: Multiple trials have documented wide interobserver variability between radiologists interpreting computed tomography colonography (CTC) exams. We sought to determine if nonradiologists could learn to interpret intraluminal findings at CTC with a high degree of sensitivity to determine if they could play a role as second readers in interpreting CTC exams. MATERIALS AND METHODS: Seven nonradiologists (five medical students, two radiologic technologists) undertook self-directed CTC training using a teaching file of 50 cases; thereafter, each reader blindly interpreted 50 cases with colonoscopic correlation (30 positive, 20 negative). Results were compared with a previously studied cohort of radiologists. The two technologists additionally repeated the exam after 6 weeks of clinical experience. RESULTS: The sensitivity of nonradiologists for small (5-9 mm) polyps, large (>9 mm) lesions, and cancers was similar to that of radiologists (0.45 versus 0.63, 0.74 versus 0.71, and 0.80 versus 0.88, respectively). After 6 weeks of clinical experience as second readers, the accuracy of one technologist significantly improved (from 74% to 90%, P = .008), whereas accuracy of the other tended toward improvement (from 74% to 86%%, P = .25). Nonradiologists detected, on average, 6/36 additional polyps (17%) missed by any radiologist, and the sensitivity of 5/7 nonradiologists was significantly greater than at least one of the radiologists (P = .05). CONCLUSION: Nonradiologists can perform similarly to radiologists in interpreting intraluminal findings at CTC, with nonradiologist performance improving even after experience with more than 100 cases. Skilled nonradiologists may play a vital role as a second reader of intraluminal findings or by performing quality control of examinations before patient dismissal.

Cohort Studies↗
PubMed2004

Understanding interpretive errors in radiologists learning computed tomography colonography.

RATIONALE AND OBJECTIVES: To determine if interpretive errors in the course of learning CT colonography are secondary to failures in detection or in characterization and determine the types of lesions frequently missed. MATERIALS AND METHODS: Fifteen radiologists completed an electronic CTC training module consisting of two parts: 1) a teaching file demonstrating the varied appearances of polyps, cancers, and pitfalls in interpreting exams; and 2) a test of 50 complete CTC datasets. Following review of each test case, radiologists were asked to indicate if and where a polyp was visualized. The module then showed each neoplasm (if any) located within the dataset. For false negative examinations, radiologists indicated if the lesion was not seen, was seen but interpreted as colonic wall or fold, or was seen but interpreted as stool or fluid. RESULTS: The average sensitivity for sessile, pedunculated, and flat polyps for these novice readers was 76%, 63%, and 32%, respectively. Average sensitivity for all morphologies of cancers (annular, polypoid, flat) was high (93%, 85%, 95%), with 8/11 missed cancers being secondary to failure in detection. The most frequently missed cancer was an annular constricting tumor (5/11). Overall, 55% (73/132) of errors were failures of detection and 45% (59/132) were errors in characterization. CONCLUSION: Radiologists learning CT colonography had slightly more errors of detection than characterization, but this difference was not statistically significant. Flat and pedunculated polyps and annular constricting cancers were the most frequently missed morphologies. Examples of these abnormalities should be emphasized in CTC training programs.

Colonic Neoplasms↗
PubMed2004

Hypophosphatemia after right hepatectomy for living donor liver transplantation.

Hypophosphatemia has been described in patients undergoing right hepatectomy for liver cancer and in living donors for liver transplantation who also received total parenteral nutrition. At the study centre, significant hypophosphatemia (0.36 mmol/L or less) requiring intravenous replacement was seen in two of the first nine living donors for adult-to-adult liver transplantation. To determine the frequency of hypophosphatemia in living donors, the authors obtained phosphate levels on stored serum samples from postoperative days 0, 1, 3 and 7 in all nine patients, none of whom were on total parenteral nutrition. Within the first week, hypophosphatemia developed in 55.6% of patients and phosphate levels returned to normal by day 7 in all nine patients. One patient had normal phosphate levels during the first week, but had profound hypophosphatemia (0.32 mmol/L) on day 14 when he presented with a Staphylococcus aureus infection of a bile collection and significant hypoxemia. The extent of hepatectomy and the rate of liver regeneration, estimated by baseline and postoperative day 7 volumetric computed tomography scans, did not correlate with the development of hypophosphatemia. In conclusion, hypophosphatemia is common in living donors undergoing right hepatectomy and may be associated with complications. All living donors should be monitored for the development of hypophosphatemia during the first two postoperative weeks.

Adult↗
PubMed2004

Intraductal papillary mucinous neoplasms of the pancreas: CT patterns of recurrence and multiobserver performance in detecting recurrent neoplasm after surgical resection.

OBJECTIVE: The purposes of our study were to describe the CT appearance of recurrent intraductal papillary mucinous neoplasms of the pancreas after surgical resection and estimate the performance of CT in detecting recurrent neoplasms. MATERIALS AND METHODS: A single unblinded reviewer characterized the presence and appearance of recurrent intraductal papillary mucinous neoplasms on 66 CT scans of 17 patients with proven recurrence, noting location and appearance of recurrent neoplasm. These results, described in this article, were summarized in tabular format and shown to three blinded observer. The observers then evaluated one postoperative CT examination from every patient at our institution who underwent surgical removal of intraductal papillary mucinous neoplasms (n = 45) for the presence or absence of local or distant recurrence. RESULTS: The unblinded reviewer found 11 cases of local recurrence. Extrapancreatic local recurrences tend to have solid components (5/6), tend to be located adjacent to the resection margin (5/6), and may exhibit vascular invasion (2/6). Intrapancreatic neoplasms are usually cystic (4/5). Nine patients had distant metastases. Prospective sensitivity for recurrent tumor ranged from 76% (13/17) to 94% (16/17). Sensitivity for local recurrence ranged from 55% (6/11) to 82% (9/11). Specificity ranged from 79% (22/28) to 96% (27/28). Interobserver agreement for predicting recurrence was moderate to substantial (kappa = 0.51-0.65). CONCLUSION: Locally recurrent intraductal papillary mucinous neoplasms of the pancreas tend to be either extrapancreatic and solid at the resection margin or intrapancreatic and cystic. CT can detect most recurrent intraductal papillary mucinous neoplasms of the pancreas with moderate to substantial interobserver agreement.

Adenocarcinoma, Mucinous↗
PubMed2003

Pancreatic malignancy: value of arterial, pancreatic, and hepatic phase imaging with multi-detector row CT.

PURPOSE: To assess the value of arterial, pancreatic, and hepatic phase imaging at multi-detector row computed tomography (CT) of the pancreas for pancreatic malignancy. MATERIALS AND METHODS: Thirty-nine patients suspected of having resectable pancreatic adenocarcinoma underwent triple-phase multi-detector row CT. Images obtained during each phase were interpreted by one radiologist who evaluated presence of tumor, vascular invasion, and flow artifacts in the superior mesenteric vein and measured attenuation of tumor, normal pancreas, aorta, and superior mesenteric vein. Results were compared with histologic, follow-up, and correlative imaging findings. RESULTS: Mean tumor-to-gland attenuation difference was greatest on images obtained in the pancreatic phase (42 HU) versus that on those obtained in the hepatic phase (35 HU) and in the arterial phase (25 HU). For tumor detection, sensitivity of the images obtained in pancreatic (0.97 [29 of 30]) and hepatic (0.93 [28 of 30]) phases was superior to that of those obtained in arterial phase (0.63 [19 of 30]) (P < or =.008). For vascular invasion detection, sensitivity of images obtained in the hepatic phase (0.83) was better than that of those obtained in the pancreatic (0.58) and arterial (0.25) phases. Images obtained in the pancreatic phase demonstrated more flow artifacts and decreased attenuation in the superior mesenteric vein, compared with the artifacts revealed on images obtained in the hepatic phase. CONCLUSION: Routine acquisition of images in the arterial phase is unnecessary for detection of pancreatic adenocarcinoma. Images of the pancreas obtained in the hepatic phase with multi-detector row CT most accurately display vascular invasion.

Adenocarcinoma↗
PubMedDate not supplied

CT enterography as a diagnostic tool in evaluating small bowel disorders: review of clinical experience with over 700 cases.

Computed tomographic (CT) enterography combines the improved spatial and temporal resolution of multi-detector row CT with large volumes of ingested neutral enteric contrast material to permit visualization of the small bowel wall and lumen. Adequate luminal distention can usually be achieved with oral hyperhydration, thereby obviating nasoenteric intubation and making CT enterography a useful, well-tolerated study for the evaluation of diseases affecting the mucosa and bowel wall. Unlike routine CT, which has been used to detect the extraenteric complications of Crohn disease such as fistula and abscess, CT enterography clearly depicts the small bowel inflammation associated with Crohn disease by displaying mural hyperenhancement, stratification, and thickening; engorged vasa recta; and perienteric inflammatory changes. As a result, CT enterography is becoming the first-line modality for the evaluation of suspected inflammatory bowel disease. CT enterography has also become an important alternative to traditional fluoroscopy in the assessment of other small bowel disorders such as celiac sprue and small bowel neoplasms.

Contrast Media↗
PubMedDate not supplied

Evaluation of benign and malignant rectal lesions with CT colonography and endoscopic correlation.

Colorectal carcinoma is a significant cause of death from cancer in the United States, and early detection and treatment are critical. Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that is a potential alternative to conventional colonoscopy for colorectal cancer screening. Rectal disease (eg, polyps, cancerous lesions, extramucosal lesions, inflammatory disease) can be especially challenging to diagnose with CT colonography because of several factors that can simulate or obscure the disease (eg, over- or underdistention, rectal tube, stool, artifacts). Familiarity with the spectrum of rectal diseases and with the potential pitfalls and technical limitations of CT colonography will help minimize interpretative and perceptual errors.

Colonography, Computed Tomographic↗