Biomedical subjects

Gerald York

Publications and source records attributed to Gerald York.

3 recordsLinked to original sources

PubMed2006

Correlation of relative permeability and relative cerebral blood volume in high-grade cerebral neoplasms.

OBJECTIVE: The purpose of this study was to correlate the degree of contrast enhancement on dynamic contrast-enhanced T1-weighted MRI and the relative cerebral blood volume (rCBV) values on T2*-weighted MRI in patients with high-grade brain neoplasms. SUBJECTS AND METHODS: Ten patients with biopsy-proven high-grade gliomas underwent dynamic contrast-enhanced MRI using T1-weighted fast spoiled gradient-echo technique (TR/TE, 8.3/1.5) during i.v. infusion of 0.1 mmol/kg of MR contrast medium. This sequence was followed within 5 minutes by dynamic susceptibility contrast (DSC) imaging (1,500/80) during i.v. infusion of 0.2 mmol/kg of MR contrast medium. Dynamic contrast-enhanced analysis was performed using the maximum-signal-intensity algorithm, and DSC analysis was performed using the negative enhancement integral program. For each tumor, we performed two comparisons: first, the average dynamic contrast-enhanced and rCBV values within a region of interest drawn around the entire contrast-enhancing tumor on a single image through the center of the lesion and, second, the highest dynamic contrast-enhanced and highest rCBV values within each tumor. Statistical analyses of the first comparison were performed using Pearson's correlation coefficient, R2 correlation coefficient, and Spearman's rank correlation and for the second comparison using Kendall's tau correlation. RESULTS: The mean signal intensity values ranged between 3.48 and 7.16 SDs above baseline values (mean, 4.89 SDs). The mean rCBV values ranged between 57.9% and 122.7% of the normal lentiform nucleus (mean, 76.6%). The Pearson's correlation coefficient was 0.867, the R2 correlation coefficient was 0.752, and the Spearman's rank correlation was 0.794 (p = 0.001). Dynamic contrast-enhanced values from the region of highest signal intensity ranged between 7.7 and 48.6 SDs above baseline values (mean, 17.3 SDs). The highest rCBV values ranged between 105% and 400% of the normal lentiform nucleus (mean, 292%). The correlation was estimated to be 0.7778 and was statistically significant at the 0.01 level of statistical significance (p = 0.0035). CONCLUSION: We found a high correlation between degree of contrast enhancement on dynamic contrast-enhanced images and rCBV values in whole tumors and in regions having the highest degree of contrast enhancement in this small study. Our findings, which suggest that relative permeability and rCBV values may be correlated in high-grade glial neoplasms, deserve further study in a larger patient population.

Adult↗

PubMed2005

Pinch-an-inch test for appendicitis.

Rebound tenderness is a widely used examination technique for patients with suspected appendicitis, but it can be quite uncomfortable. An alternative test for peritonitis is termed the "pinch-an-inch" test. This report describes two patients who presented with mild abdominal pain who subsequently were found to have appendicitis. In both patients, classic peritoneal signs were absent, but the pinch-an-inch test was positive. The experienced physician's bedside clinical examination remains the most critical component for rapidly identifying peritonitis. Although rebound tenderness is a widely used examination, it is uncomfortable and may be inaccurate. To perform the pinch-an-inch test, a fold of abdominal skin over McBurney's point is grasped and elevated away from the peritoneum. The skin is allowed to recoil back briskly against the peritoneum. If the patient has increased pain when the skin fold strikes the peritoneum, the test is positive and peritonitis probably is present.

Adult↗

PubMed2005

Association of internal carotid artery injury with carotid canal fractures in patients with head trauma.

OBJECTIVE: The purpose of our study was to determine the degree to which carotid canal fracture and other CT findings are associated with internal carotid artery (ICA) injury in patients with head trauma. MATERIALS AND METHODS: Three neuroradiologists retrospectively evaluated CT scans and cerebral angiograms of 43 patients who underwent cerebral angiography within 7 days after blunt cranial trauma over a 5-year period. Seventeen patients underwent unilateral and 26 had bilateral carotid angiography. Angiograms were evaluated for ICA injury and CT scans were evaluated for carotid canal fracture, brain contusion, subarachnoid hemorrhage, basilar skull fracture, subdural hematoma, soft-tissue swelling, sphenoid sinus air-fluid level, and other skull fracture. We recorded the number of true-positive (+CT, +angiogram), true-negative (-CT, -angiogram), false-positive (+CT, -angiogram), and false-negative (-CT, +angiogram) studies. We determined the sensitivity, specificity, positive predictive value, and negative predictive value for each CT finding. RESULTS: We identified 21 carotid canal fractures in 17 patients. Eleven ICA injuries were seen in 10 patients. Six patients with ICA injury had a carotid canal fracture. The presence of a carotid canal fracture had a sensitivity of 60% and specificity of 67% for detection of injury to the ICA passing through that canal. These values were similar to those for other CT findings. CONCLUSION: Sensitivity, specificity, positive predictive value, and negative predictive value of carotid canal fracture were only moderately good for determining the presence of ICA injury and were similar to other CT findings not typically associated with ICA injury.

Adult↗