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Joel F Platt

Publications and source records attributed to Joel F Platt.

7 recordsLinked to original sources
PubMed2003

Helical computed tomography for identification of crossing vessels in ureteropelvic junction obstruction-comparison with operative findings.

OBJECTIVES: To evaluate the use of contrast-enhanced helical computed tomography (HCT) scanning with three-dimensional reconstructions as a possible identifier of crossing vessels in ureteropelvic junction (UPJ) obstruction. Endoscopic treatment of UPJ obstruction has a success rate that approaches 90%. These results drop to 40% in the presence of crossing vessels. Unrecognized crossing vessels can also result in significant hemorrhage during endopyelotomy. The presence of crossing vessels is, for many, an indication for open or laparoscopic UPJ repair. Therefore, accurate preoperative imaging is crucial for appropriate treatment planning. METHODS: Our study population consisted of 18 patients evaluated and treated for UPJ obstruction at the University of Michigan Health System. These patients underwent routine contrast-enhanced preoperative HCT scanning before UPJ repair. A prior history of failed endoscopic treatment, patient preference, and HCT findings of crossing vessels were indications for open or laparoscopic repair. The imaging findings were compared with open findings during laparoscopic or open pyeloplasty. RESULTS: An HCT finding of the presence of crossing vessels was a significant positive predictor, with a value of 100%. The sensitivity in this population was 91% and the specificity was 100%. No difference was noted between the detection of arterial or venous crossing vessels. The positive predictive value was 100%, and the negative predictive value was 88%. CONCLUSIONS: HCT is an accurate predictor of the presence of crossing vessels in UPJ obstruction. Because crossing vessels may have a profound impact on treatment outcome, HCT can serve as an effective, noninvasive, preoperative screening tool.

Adult↗
PubMed2003

Aortic intimal tears: detection with spiral computed tomography.

PURPOSE: To determine the frequency, locations, and sizes of aortic intimal tears detected using spiral computed tomography (CT). METHODS: CT scans (26 single detector and 26 multidetector studies) from 52 patients with an unoperated aortic dissection and a patent false lumen were evaluated on a workstation. The number, location, and size of aortic tears were recorded and compared between the following groups: acute and chronic dissection, type A and type B, and single detector and multidetector studies. RESULTS: In 52 patients, 129 tears were identified (mean 2.48 per patient, median 2, range 1-7). There were no significant differences in the number or size of tears between the acute and chronic, the type A and type B, or the single detector and multidetector groups (p>0.05). The most common locations for tears were the descending aorta (57, 44%) and the juxtarenal region (26, 20%). Within the type B category, there was no significant difference in tear locations between the acute and chronic groups (p>0.05). The majority of tears (88, 68%) were < or =1 cm in each dimension. Tears in the thoracic aorta were significantly larger than abdominal aortic tears (p<0.05). CONCLUSIONS: All patients with an aortic dissection and a patent false lumen demonstrated one or more aortic intimal tears using spiral CT. Although most tears were small (</=1 cm), they were usually easily visualized.

Acute Disease↗
PubMed2003

Multidetector CT of the liver and hepatic neoplasms: effect of multiphasic imaging on tumor conspicuity and vascular enhancement.

OBJECTIVE: Our aim was to determine which of three contrast-enhanced phases (early arterial, late arterial, or portal venous) was optimal for achieving maximal enhancement of the celiac artery, portal vein, and hepatic parenchyma. We also wanted to learn which phase provided the maximal tumor-to-parenchyma difference when using multidetector CT (MDCT) with fixed timing delays. MATERIALS AND METHODS: Fifty-two patients with suspected or known hepatic tumors underwent multiphasic contrast-enhanced MDCT using double arterial (early and late arterial) and venous phase acquisitions with fixed timing delays. All patients were administered 150 mL of IV contrast material at an injection rate of 4 mL/sec. Images were acquired at 20 sec for the early arterial phase, 35 sec for the late arterial phase, and 60 sec for the portal venous phase. Attenuation measurements of the celiac artery, portal vein, normal hepatic parenchyma, and the hepatic tumor were compared. Three reviewers independently and subjectively rated tumor conspicuity for each of the three phases. Ratings were compared using kappa statistics. RESULTS: Late arterial phase images showed maximal celiac axis attenuation, whereas portal venous phase images revealed the highest portal vein and normal hepatic parenchymal attenuation. Maximal tumor-to-parenchyma differences for hypovascular tumors was superior in the portal venous phase, but we found no significant differences in maximal tumor-to-parenchyma differences for hypervascular tumors among the evaluated phases. On subjective analysis, interobserver agreement was moderate to very good for the three phases. All three reviewers graded both hypovascular and hypervascular tumor conspicuity as superior in either the late arterial phase or the portal venous phase in most patients. In only one patient was the early arterial phase graded as superior to the late arterial and portal venous phases (by two of the three reviewers). CONCLUSION: When MDCT of the liver is performed using fixed timing delays, maximal vascular and hepatic parenchymal enhancement is achieved on either late arterial phase or portal venous phase imaging. In most patients, early arterial phase imaging does not improve tumor conspicuity by either quantitative or subjective analysis.

Adult↗
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↗
PubMed2002

Adrenal masses: characterization with combined unenhanced and delayed enhanced CT.

PURPOSE: To assess the accuracy of a dedicated adrenal computed tomographic (CT) protocol. MATERIALS AND METHODS: One hundred sixty-six adrenal masses were evaluated with a protocol consisting of unenhanced CT, and, for those with attenuation values greater than 10 HU, contrast material-enhanced and delayed enhanced CT. Attenuation values and enhancement washout calculations were obtained. An adenoma was diagnosed if a mass had an attenuation value of 10 HU or less at unenhanced CT or a percentage enhancement washout value of 60% or higher. RESULTS: The final diagnosis was adenoma in 127 masses and non-adenoma in 39. Masses measuring more than 10 HU on unenhanced CT scans were confirmed at biopsy (n = 28) or were examined for stability or change in size at follow-up CT performed at a minimum interval of 6 months (n = 33). Thirty-six (92%) of 39 non-adenomas and 124 (98%) of 127 adenomas were correctly characterized. The sensitivity and specificity of this protocol were 98% and 92%, respectively. This protocol correctly characterized 160 (96%) of 166 masses. CONCLUSION: With a combination of unenhanced and delayed enhanced CT, nearly all adrenal masses can be correctly categorized as adenomas or non-adenomas.

Adenoma↗
PubMedDate not supplied

Computed tomography appearances of hypervascular hepatic tumors after percutaneous radiofrequency ablation therapy.

A retrospective review of the computed tomography (CT) findings of patients with hypervascular liver tumors (26 hepatocellular carcinomas and 2 metastases [1 periampullary carcinoma and 1 neuroendocrine tumor]) who underwent percutaneous ultrasound-guided radiofrequency ablation (RFA) was performed. CT images consisted of nonenhanced and dual-phase contrast-enhanced helical CT images performed on a multidetector CT scan. Findings indicative of adequate tumor ablation on multidetector CT scanwere complete nonenhancement of the treated tumor with or without faint, thin, peripheral rim enhancement. Ablated lesions that showed complete nonenhancement on initial and subsequent follow-up CT examinations either remained stable or became progressively smaller. Thick rim or nodular peripheral enhancement was indicative of tumor residual or recurrence.

Aged↗