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Biomedical subjects

W N Hanafee

Publications and source records attributed to W N Hanafee.

96 records · Page 6Linked to original sources
PubMedDate not supplied

MR imaging-guided interstitial Nd:YAG laser phototherapy: dosimetry study of acute tissue damage in an in vivo model.

A dosimetry study of acute tissue damage induced by interstitial application of the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser was performed with magnetic resonance (MR) imaging. The MR appearance of the lesion was correlated with gross and histopathologic findings. Seventy-six lesions were induced in rabbit muscle with laser power outputs of 5-20 W and exposure times of 20-600 seconds. MR imaging was performed immediately after laser exposure. T2-weighted spin-echo images clearly showed the acute thermal injuries caused by laser energy deposition and correlated best with histopathologic findings. These images showed three distinct layers, corresponding to central ablation, coagulative necrosis, and interstitial edema, respectively, in the pathologic findings. Lesion diameters measured on MR images showed a linear correlation with those in gross sections. Lesion volume increased not only with increasing total energy delivered but with increasing power output for a fixed total energy delivered. MR imaging is an accurate modality for dosimetry studies of laser-induced acute lesions.

Animals↗
PubMedDate not supplied

Diagnosis and treatment of carotid body tumors.

The diagnosis and management of carotid body tumors are discussed, including the importance of good arteriography which allows visualization of all major feeding vessels. These include the carotid bulb, internal and external carotid arteries and the often neglected but important vertebral and ascending cervical arteries. Emphasis is placed on the importance of establishing tourniquet control of the common, internal and external carotid arteries. Surgeons removing carotid body tumors should be experienced in arterial wall repair by means of vascular shunts, end-to-end arterial anastomosis, and vein graft replacement of a segment of arterial wall.

Angiography↗
PubMedDate not supplied

Computerized tomography scanning of the temporal bone.

Computerized tomography (CT) scanning has reached a degree of sophistication that requires alteration of technical factors to demonstrate different parameters of temporal bone pathology. The techniques for pontocerebellar angle display, eustachian tube, middle ear pathology, and overall temporal bone display are quite different. Close cooperation between the radiologist and otologic surgeon are required for optimal use of CT scanning advances.

Adult↗
PubMedDate not supplied

Computerized tomography in hearing loss and disequilibrium states.

Computerized tomographic (CT) scanning for intracanalicular tumors requires air as a contrast agent within the internal auditory canal and special computer manipulations of the image to visualize small tumors. The same computer manipulations of CT scans provide detail of the middle and inner ear structures not available by non-CT tomographic techniques. The demonstration of horizontal semicircular canal fistula is one area in which CT scanning is clearly superior. Some pitfalls of the technique and interpretation of it will be discussed.

Cholesteatoma↗
PubMedDate not supplied

Fat-suppression failure artifacts simulating pathology on frequency-selective fat-suppression MR images of the head and neck.

PURPOSE: To describe fat-suppression failure artifacts and to caution against their misinterpretation. METHOD: Magnetic-susceptibility artifacts were studied in a phantom model and the results were compared to MR images obtained in clinical cases. FINDINGS: Artifacts manifested themselves as regions of focal fat-suppression failure and appeared as bright signals without geometric distortions at magnetic-susceptibility interfaces along the static field (z) direction. The location and extent of these artifacts were independent of either frequency or phase-encoding direction and are different from those observed in gradient-echo images. CONCLUSIONS: In representative clinical MR exams, these artifacts were identified in the high nasopharynx and low orbit and should not be misinterpreted as pathology.

Artifacts↗