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Biomedical subjects

G L Dillehay

Publications and source records attributed to G L Dillehay.

10 recordsLinked to original sources
PubMed1997

Infiltrator Angioplasty Balloon Catheter: a device for combined angioplasty and intramural site-specific treatment.

OBJECTIVES: We describe a new angioplasty device (Infiltrator Angioplasty Balloon Catheter; IABC) with intramural drug delivery capability. The conventional balloon part of the device, when inflated, dilates the vessel or has three rows of longitudinally mounted infiltrator nipples to penetrate the tunica media. Through an independent infiltrator port and nipples, drugs can be infiltrated directly into the vessel wall. METHODS: The device was tested in 117 normal coronary arteries of 58 farm pigs. RESULTS: (1) The infiltration procedure does not damage the vessel angiographically or histologically. At the infiltration site, the endothelial layer and the internal elastic lamina has a controlled interruption, and the infiltrated fluid is distributed among the medial layers, causing a mild focal edema and medial thickening (1.8 times on average). (2) Rhodamine tracer is circularly and evenly distributed through the whole width of the vessel wall within 10 min after infiltration. (3) Two weeks after the infiltration procedure, the medial layer reveals mild local thickening and remodelling without luminal narrowing. (4) Of the intramurally infiltrated Tcm99-labeled surfurcolloid, 83.8% is detectable at 5 min after the delivery procedure by gamma camera. (5) The IABC, if oversized, is able to achieve angiographic dilatation in normal pig coronary arteries, causing histologic damage similar to or less than that induced by conventional balloon dilatation. CONCLUSIONS: The IABC can deliver fluid-phase substances directly into the vessel wall with microliter accuracy and with 90% efficiency without significant acute and subacute damage to the vessel wall. It is also suitable for combined dilatation and local drug delivery.

Angioplasty, Balloon, Coronary↗
PubMed1993

The effect of fine-needle aspiration biopsy on the thyroid scan.

Fine-needle aspiration biopsy (FNAB) is the most sensitive and specific procedure in diagnosing benign from malignant thyroid nodular disease. The effects of a FNAB on the thyroid scan, however, have never been studied. This assumes importance because a hot nodule on scan has been advocated as useful to differentiate certain benign from malignant follicular neoplasms. Thyroid scans were performed before and after FNAB on 11 patients with nodular thyroid disease and an area of normal or increased uptake either in the nodule or in a contralateral enlarged lobe to determine if the biopsy changed the pattern of isotope uptake. For this study, biopsies were done in the area of normal or increased uptake. In two patients, there was a reduction in isotope concentration in three nodules after FNAB, whereas no change was demonstrable in nine other patients. Review of the literature revealed a number of prior reports of hemorrhage, necrosis, or infarction of thyroid nodules after FNAB. Based on these data and the demonstration of a change in scan pattern in a patient following FNAB, it is concluded that FNAB may decrease the isotope uptake in thyroid nodules; therefore, the concept of clinical judgments being based on the scan pattern after FNAB should be reevaluated.

Adult↗
PubMed1989

Errors in the determination of left ventricular functional parameters.

Gated blood-pool scans of the left ventricle are routinely employed for determination of the left ventricular ejection fraction. Recently, attempts have been made to evaluate other left ventricular functional parameters. These values include peak emptying rate (PER), time to peak emptying rate (TPER), peak filling rate (PFR), and time to peak filling rate (TPFR). In studying these parameters clinically, we identified many software errors and assumptions that impact on these values. These errors may also affect the determination of left ventricular ejection fraction (EF). We conclude that before any serious investigation of left ventricular functional parameters is undertaken, a detailed evaluation and standardization of the acquisition and edge detection algorithms must be performed.

Diagnostic Errors↗
PubMed1986

Ventilation-perfusion scintigraphy in suspected pulmonary embolism: correlation with pulmonary angiography and refinement of criteria for interpretation.

Retrospective analysis of 139 ventilation-perfusion (V/Q) lung scans obtained for suspected pulmonary embolism (PE) was undertaken, using the Biello criteria for interpretation. All scans were correlated with chest radiographs obtained within 24 hours and with pulmonary angiograms obtained within 72 hours of the V/Q study. The prevalence of PE in the high-, intermediate-, and low-probability groups was 89.5%, 49.3%, and 3.6%, respectively. Using minor modifications of these criteria, V/Q scans interpreted as high or low probability had a sensitivity of 97.1%, specificity of 94.3%, and accuracy of 95.7%. Perfusion defects corresponding to radiographic abnormalities that were present for at least 10 days were less likely to be associated with PE. Separate analysis of 27 perfusion-only lung scans that met all other criteria for inclusion in the study confirmed the nonspecificity of perfusion-only lung imaging and indicated the need for ventilation imaging with Tc-99m-DTPA aerosol or Kr-81m gas for portable studies.

Adolescent↗
PubMedDate not supplied

Radionuclide cerebral imaging for confirmation of brain death in children: the significance of dural sinus activity.

Radionuclide cerebral imaging revealed no cortical flow, but recorded persistent dural sinus activity in 14 of 55 clinically brain dead children. Of these 14 children, 13 had isoelectric electroencephalograms. Postmortem liquefactive necrosis was present in 7 cases. Although studies that demonstrated the absence of flow were confirmatory of brain death, dural sinus radioactivity in the delayed static images persisted in the presence of brain death.

Adolescent↗
PubMedDate not supplied

The ultrasonographic characterization of tendons.

Ultrasonography has not been utilized in the diagnosis of musculoskeletal disorders. However, the superficial location of tendons and ligaments lend themselves to evaluation by this modality. The ultrasonographic characteristics of the normal Achilles tendon are described in both the rabbit and man. The characteristic ultrasonographic findings after injury to the Achilles tendon are also determined. This imaging technique provides a sharp definition of the tendon and surrounding structures and easily demonstrates abnormalities. The superficially located quadriceps tendon is also well visualized by ultrasound and representative examples are shown. Ultrasound should be considered as another useful method for evaluation of these superficial musculoskeletal structures.

Achilles Tendon↗