Biomedical subjects

James H Ellis

Publications and source records attributed to James H Ellis.

6 recordsLinked to original sources

PubMed2005

Optimization of multi-detector row CT urography: effect of compression, saline administration, and prolongation of acquisition delay.

PURPOSE: To retrospectively compare the effects of abdominal compression, intravenous saline hydration, and two imaging delays on both distention and opacification of the intrarenal collecting system and ureter during multi-detector row computed tomographic (CT) urography. MATERIALS AND METHODS: Institutional review board approval for reviewing images and medical records of the patients was obtained; informed patient consent was not required. Excretory phase images obtained from multi-detector row CT urography in 85 patients (57 men, 28 women) were reviewed. Examinations were performed by using one of four techniques: abdominal compression and intravenous hydration with 250 mL of normal saline, compression only, intravenous hydration with saline only, and neither compression nor saline hydration. Excretory phase imaging was performed at 300 and 450 seconds for each patient. Two reviewers measured urinary tract distention on transverse images and graded opacification and image quality on volume-rendered images. Effects were compared by using statistical mixed models with repeated-measures analysis of variance. RESULTS: Saline hydration significantly improved opacification (P = .02) and overall image quality (P < .001) of the intrarenal collecting system and proximal ureter. Delayed excretory phase image acquisition of 450 seconds significantly increased distention of the intrarenal collecting system and proximal ureter (P < .001). No significant effects involving the lower segment of the ureter were seen with any technique; however, there were fewer nonvisualized distal ureteral segments with the longer imaging delay. CONCLUSION: Compression does not significantly improve distention or opacification of the urinary tract. Saline hydration is effective in improving opacification of the proximal urinary tract. Longer imaging delays improve distention of the proximal urinary tract and may aid in visualization of the lower segment of the ureter.

Adolescent↗

PubMed2005

Incidence of acute appendicitis in patients with equivocal CT findings.

OBJECTIVE: The purpose of our study was to determine the incidence of acute appendicitis in patients for whom the CT interpretation is deemed equivocal. MATERIALS AND METHODS: Of 1,344 patients referred for CT with suspected appendicitis between January 1998 and December 2002, 172 patients were identified in whom the radiographic findings were equivocal. Two radiologists reviewed the equivocal CT cases, reassessing appendiceal size and the presence of right lower quadrant stranding, fluid, or an appendicolith. The reviewers' findings were correlated with surgical pathology reports and clinical follow-up. RESULTS: Fifty-three (31%) of 172 patients with indeterminate findings on CT scans were subsequently diagnosed with appendicitis. For reviewers 1 and 2, respectively, appendicitis was present in five (14%) of 36 and six (13%) of 47 patients who had isolated appendiceal diameter less than 9 mm, and in 11 (52%) of 21 and in 10 (50%) of 20 patients who had isolated appendiceal dilatation equal to or greater than 9 mm. If a normal diameter appendix (< 6 mm) was visualized in a patient who had right lower quadrant stranding or fluid, appendicitis was present in only one (17%) of six and in four (27%) of 15 patients for reviewers 1 and 2, respectively. If the appendix could not be identified but there was right lower quadrant stranding or fluid, appendicitis was present in seven (37%) of 19 and in eight (53%) of 15 patients. CONCLUSION: Appendicitis is encountered in about 30% of patients with equivocal findings on CT, and the diagnosis should be considered in most of these patients if they are appropriately symptomatic. However, when the appendix measures less than 9 mm alone, the likelihood of appendicitis is much smaller.

Acute Disease↗

PubMed2005

MDCT urography of upper tract urothelial neoplasms.

OBJECTIVE: The purpose of our study was to review the MDCT urography appearance of pathologically proven transitional cell carcinomas of the renal collecting system and ureter and to correlate the MDCT urography findings with pathology findings. MATERIALS AND METHODS: Of 370 MDCT urography examinations performed over an 18-month period, 18 patients were diagnosed with 27 renal collecting system or ureteral urothelial neoplasms at endoscopic biopsy (n = 8) or surgery (n = 19). Initial MDCT reports were reviewed to determine the sensitivity of original reviewers in detecting these neoplasms. Two radiologists also retrospectively reviewed these scans and characterized the CT appearance of the neoplasms on both axial CT and 3D reformatted images. Findings at retrospective review were correlated with pathology results to determine whether any CT features could be used to predict tumor grade. RESULTS: Eighteen of 27 neoplasms were prospectively identified on MDCT urography, and an additional six neoplasms were detected on retrospective review. Three ureteral neoplasms could not be visualized. The 24 retrospectively detected neoplasms had three distinct MDCT appearances: circumferential urothelial wall thickening (n = 14), small masses (> 5 mm in maximal diameter) (n = 5), and large masses (> 5 mm in maximal diameter) (n = 5). All detected lesions could be seen on axial excretory phase images provided wide window settings were reviewed; however, only six were detected on 3D reconstructions. MDCT urography appearance did not correlate with tumor grade. CONCLUSION: MDCT urography is a promising technique for detecting upper urinary tract neoplasms. The static 3D reconstructions used in this study are insufficient for visualization. Axial image review remains essential for tumor identification.

Aged↗

PubMed2003

Incorporating patient-centered outcomes in the analysis of cost-effectiveness: imaging strategies for renovascular hypertension.

OBJECTIVE: Our aim was to assess the contribution of patient-centered short-term disutilities and quality-of-life measures in the cost-effectiveness analysis of CT angiography, MR angiography, and conventional angiography in patients with medication-resistant hypertension. MATERIALS AND METHODS: A decision analytic model compared the life expectancy and incremental cost per life year using three initial diagnostic tests in a cohort of hypothetical individuals with medication-resistant hypertension over a range of renal artery stenosis probabilities: CT angiography (sensitivity, 96%; specificity, 96%; cost, $865); MR angiography (98%, 94%, $850); and conventional angiography (99%, 99%, $2,627). All imaging strategies were compared with a base case scenario mimicking the natural history of medication-resistant hypertension and with a scenario immediate enhanced medical therapy without prior imaging. Individuals without evidence of renal artery stenosis on initial testing underwent conventional angiography if enhanced medical therapy failed to control hypertension. Individuals diagnosed with renal artery stenosis on MR angiography required conventional angiography for definitive stent treatment ($11,1223). Blood pressure response to renal artery stenting or enhanced medical therapy varied according to blood pressure, as did the incidence of myocardial infarction and stroke resulting from hypertension. Patients who progressed to end-stage renal disease received dialysis ($60,000 per year). Quality-of-life adjustments were made for patients with hypertension, end-stage renal disease, myocardial infarction, and stroke. Short-term disutilities from undergoing an imaging test were included. The analysis accounted for direct costs derived from Medicare reimbursements and total costs derived from the literature. RESULTS: All imaging strategies were cost-effective compared with enhanced medical therapy alone or with natural history. When only direct costs were considered, MR angiography was the preferred strategy, with conventional angiography as a cost-effective alternative to MR angiography. When total costs were considered, conventional angiography dominated all other strategies. Adjusting for quality of life decreased the incremental cost-effectiveness ratios, making an already competitive strategy a more favorable alternative to the base case. Adjusting for test-related disutility did not significantly influence the cost-effectiveness of any of the imaging tests. Despite marked variation in the key clinical and cost variables, MR angiography remained the most cost-effective strategy. CONCLUSION: In the evaluation and treatment of medication-resistant hypertension, strategies that included preliminary imaging saved more lives than did the immediate institution of enhanced medical therapy at a lesser cost.

Cost-Benefit Analysis↗

PubMed2002

Urinary tract abnormalities: initial experience with multi-detector row CT urography.

PURPOSE: To evaluate multi-detector row computed tomographic (CT) urography for detection of urinary tract abnormalities. MATERIALS AND METHODS: Sixty-five patients referred from the urology service, in whom urinary tract abnormalities were strongly suspected, underwent multi-detector row CT urography. The technique included unenhanced, nephrographic, compression, and excretory-phase images through the abdomen and pelvis. Transverse images and three-dimensional reformations were reviewed by one of two radiologists. Findings were retrospectively compared with results of urinalysis, cystoscopy and/or ureteroscopy, and/or surgery. RESULTS: Multi-detector row CT urography depicted many clinically diagnosed urinary tract abnormalities, including 15 of 16 uroepithelial malignancies, five congenital anomalies, five urinary tract calculi, and 18 calyceal and/or papillary, 30 renal pelvic and/or ureteral, and 25 bladder abnormalities. All abnormalities were detected on transverse images. These abnormalities included diffuse urothelial wall thickening in four patients (three of whom had transitional cell carcinoma), a renal abscess, a colovesical fistula, and incidentally detected extrarenal disease (a liver mass, hepatic metastases, lymph node metastases, an aortic dissection, and a pheochromocytoma; each of these findings was seen in one patient). CONCLUSION: Multi-detector row CT urography is a useful method for detecting urinary tract abnormalities.

Adult↗

PubMedDate not supplied

Improving educational computer exhibits at radiologic meetings by modifying computer environment: results of an observational study.

An observational study of educational computer exhibits (ECEs) at the 86th Scientific Assembly and Annual Meeting of the Radiological Society of North America in 2000 was performed to determine the frequency with which the ECEs were in working order. At any given time, an average of 10% of the 71 exhibits were found to be inoperable, and, although some exhibits were functioning 100% of the time, others were not functioning up to 55% of the time. These observations underscore the importance of careful design when creating a computer-based exhibit for a meeting. Downtime of ECEs at meetings is the result of both intentional and unintentional user actions. Given that traditional poster presentations are "working" 100% of the time, modifications made to the environment of an exhibit computer to reduce downtime would be beneficial. Several relatively easy computer configuration steps can be taken that will likely improve the amount of time that an exhibit is functional. Electronic exhibits allow a more interactive experience for users and, with some assistance, will continue to be an effective educational tool.

Audiovisual Aids↗