Biomedical subjects

J G Parravano

Publications and source records attributed to J G Parravano.

3 recordsLinked to original sources

PubMed1991

Aortic dissection: atypical patterns seen at MR imaging.

Aortic dissection is typically manifested by an intimal flap separating true and false lumens. Atypical patterns lacking an intimal flap can occur, however, and are less well recognized. In this study, the authors review their experience with atypical patterns at magnetic resonance (MR) imaging. They evaluated the T1-weighted and gradient-echo MR images of the entire aorta in 64 patients with aortic dissection. In nine patients (14%) aortic wall thickening was the only sign of dissection in the thorax. In three of these cases, an intimal flap was found in the abdominal aorta; the other six patients had no flap in any region of the aorta, and this led to false-negative angiographic results in three cases. Aortic wall thickening as an atypical sign of dissection was seen more frequently in acute (29%) than in chronic (7%) dissection and was seen in only patients without Marfan syndrome. Two patients with atypical acute dissection at initial examination developed a clearly identifiable intimal flap at follow-up. Aortic wall thickening may represent the only sign of aortic dissection. In some cases, imaging the entire aorta can enable recognition of dissection in atypical cases.

Acute Disease↗

PubMedDate not supplied

Dimensions of the optic nerves, chiasm, and tracts: MR quantitative comparison between patients with optic atrophy and normals.

OBJECTIVE: The dimensions of the optic nerves, chiasm, and tracts were determined in normal patients and in patients with clinical evidence of optic atrophy to establish whether there was a significant difference between the two groups. MATERIALS AND METHODS: The authors analyzed thin section coronal MRI of 110 patients. Seventy-seven patients were normal, 20 had visual impairment without funduscopic evidence of optic atrophy, and 13 had visual impairment with funduscopic evidence of optic atrophy. RESULTS: The normal mean dimensions were (height x width): optic tracts 2.8 x 5.1 mm; nerves 3.0 x 5.9 mm; chiasm 3.5 x 15.0 mm. The mean dimensions in the optic atrophy group were significantly less (p < 0.01): optic tract 2.1 x 4.7 mm; nerve 2.7 x 5.8 mm; chiasm 2.6 x 12.6 mm. CONCLUSION: The reduced mean dimensions in the optic atrophy group are statistically significant but due to individual variability and errors inherent in measuring small structures, these measurements may be difficult to apply clinically. The most clinically useful measurement is the chiasm width. A width < 13.5 mm correlates well with funduscopic evidence of optic atrophy.

Adolescent↗

PubMedDate not supplied

Postprocessing conventional vs. fast spin echo MR images.

By postprocessing MR images on a medical imaging workstation, technologists can simultaneously visualize anatomy in the coronal, sagittal and transverse planes and use "melt-through" to visualize anatomy at any orientation desired. In this article, researchers compare the post-processing of pelvic images obtained through conventional and fast spin echo MR techniques. The research showed that the combination of fast spin echo techniques and post-processed MR images provided more accurate 3-D visualization.

Color↗