Biomedical subjects

Jeff L Fidler

Publications and source records attributed to Jeff L Fidler.

5 recordsLinked to original sources

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↗