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M G Hueftle

Publications and source records attributed to M G Hueftle.

5 recordsLinked to original sources
PubMed1989

Gadolinium-DTPA-enhanced MR imaging of the postoperative lumbar spine: time course and mechanism of enhancement.

To define the time course and mechanism of enhancement of epidural fibrosis after gadolinium-DTPA (Gd-DTPA) injection, we undertook a three-part study in humans and dogs with epidural scar after spine surgery. First, the dynamic in vivo contrast-enhancing properties of epidural scar were assessed by using sequential fast (18-sec) spin-echo sequences after contrast injection. Epidural scar in dogs rapidly enhanced; peak enhancement (101%) was 6 min after injection, with a slower decline toward baseline to 45% after 44 min. Epidural fibrosis in patients followed a similar pattern, with a maximum enhancement of 73% after 5 min. Paraspinal muscle had a lower peak enhancement in both patients (36%) and dogs (22%). Second, vascular injection in two dogs with India ink demonstrated multiple small vessels throughout the epidural scar. Third, light and electron microscopy was performed on epidural scar obtained at reoperation in both patients and dogs. Light microscopy showed multiple small capillaries scattered throughout a background of collagen. Electron microscopy demonstrated a wide variation in the junctions between endothelial cells ranging from "tight" to "loose." Regions of endothelial discontinuity were also visualized. This study suggests that Gd-DTPA diffuses rapidly into the extravascular space in epidural scar, with a slower, net movement toward the intravascular compartment as the agent is renally filtered. The contrast agent transgresses the endothelium through "leaky" intercellular junctions and areas of endothelial discontinuity.

Animals↗
PubMed1988

Lumbar spine: postoperative MR imaging with Gd-DTPA.

Thirty patients with failed back surgery syndrome were studied to evaluate the effectiveness of magnetic resonance (MR) imaging with gadolinium-diethylenetriaminepentaacetic acid/dimeglumine (Gd-DTPA) in differentiating postoperative epidural fibrosis (scar) from recurrent disk herniation. Pre- and postcontrast MR images were interpreted without access to other diagnostic, surgical, or pathologic findings. Seventeen patients had surgical and pathologic correlation of the MR findings at 19 disk levels. The precontrast studies had a sensitivity, specificity, and accuracy of 100%, 71%, and 89%, respectively. The enhanced MR studies correctly depicted the character of abnormal epidural soft tissue in 17 patients at all 19 levels. Scar showed heterogeneous enhancement on the early T1-weighted spin-echo images obtained within 10 minutes after contrast material administration. Herniated disk did not show significant enhancement on the early studies but showed variable degrees of enhancement on delayed images in nine of 12 cases. Other criteria were found to be less useful than the pattern of enhancement. Results indicate that precontrast and early postcontrast T1-weighted spin-echo studies are highly accurate in separating epidural fibrosis from herniated disk.

Adult↗
PubMedDate not supplied

MR imaging of brain stem gliomas.

Magnetic resonance (MR) and CT examinations of 26 patients with the established or clinically suspected diagnosis of brain stem glioma were reviewed. Eleven tumors were seen on both MR and CT. The entire extent of the abnormality was better outlined on MR, although CT was more advantageous in demonstrating cystic components and calcium deposition. Magnetic resonance and CT depicted focal intratumoral hemorrhage equally. Magnetic resonance was found to be particularly suitable to follow up the progression or regression of the disease. Of particular interest were two patients with evidence of aqueductal obstruction but normal CT appearance of the midbrain; the causative abnormality, believed to be a glioma, was clearly shown by MR imaging. In nine patients the normal appearance was helpful to exclude the possibility of a brain stem glioma. Thus far, results have shown 100% sensitivity (true positive ratio) and specificity (true negative ratio) with MR in the evaluation of brain stem gliomas. It is concluded that MR imaging should be the examination of choice and could be the definitive screening procedure in patients with suspected brain stem glioma.

Adolescent↗