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Biomedical subjects

L A Loevner

Publications and source records attributed to L A Loevner.

45 records · Page 3Linked to original sources
PubMed1995

MR evaluation of frontal sinus osteoplastic flaps with autogenous fat grafts.

PURPOSE: To investigate the MR findings in patients who have had osteoplastic frontal sinus flaps placed for inflammatory sinonasal disease. METHODS: The MR images of 13 patients who had improvement of symptoms after osteoplastic frontal sinus flap placement with fat autograft were prospectively evaluated for the presence of high intensity on T2-weighted scans, contrast enhancement, and replacement of frontal sinus fat by lower-signal soft tissue. All studies were performed on a 1.5-T unit using a 5-in round surface coil placed over the nasion. Sagittal T1-weighted, axial and coronal fast spin-echo T2-weighted, and precontrast and postcontrast axial and coronal T1-weighted images were obtained through the operative bed. The T2-weighted and postgadolinium sequences were done with a fat-suppression technique. RESULTS: Hyperintensity within the frontal sinuses on T2-weighted images and enhancement (peripherally and/or centrally where fat was replaced with soft tissue) were found to some degree in all patients. The degree of replacement of frontal sinus fat with soft tissue ranged from 4% to 85% (mean, 43%). Five patients with persistent symptoms had no distinguishing MR features when compared with asymptomatic patients. CONCLUSIONS: Although increased T2-weighted intensity, fat replacement, and enhancement are findings compatible with inflammation, these changes may be seen in patients who are asymptomatic after placement of osteoplastic frontal sinus flaps; they may represent the normal granulation process. MR findings after flap placement are nonspecific and have limited utility in distinguishing symptomatic patients with recurrent inflammatory disease from asymptomatic patients whose imaging findings are related to postoperative scar tissue.

Adipose Tissue↗
PubMed1988

Herpes esophagitis: sensitivity of double-contrast esophagography.

During a 10-year period between 1978 and 1987, there were 25 confirmed cases of herpes esophagitis with positive esophageal brushings, biopsies, and/or cultures for the herpes simplex virus. Eighteen of those patients had double-contrast esophagrams, but two were excluded from our study because they had combined fungal and viral esophagitis. All of the remaining 16 patients were symptomatic, and 14 were immunocompromised. Herpes esophagitis was diagnosed on the original radiographic reports in nine (56%) of those 16 patients. In all nine, double-contrast radiographs revealed discrete, superficial ulcers on a relatively normal background mucosa without significant plaque formation. In the remaining seven patients, double-contrast esophagrams revealed plaquelike lesions that were indistinguishable from those of Candida esophagitis (four cases), thickened folds (two cases), and a giant esophageal ulcer (one case). During the same period, herpes esophagitis was diagnosed on seven other double-contrast esophagrams in which histologic, cytologic, and virologic studies were negative for the herpes simplex virus. However, the endoscopic findings were also suspicious for herpes esophagitis in six of those cases, suggesting that they may represent true-positive cases in which there was inadequate tissue sampling. Thus, our experience indicates that radiographic abnormalities can almost always be detected on double-contrast esophagrams in patients with herpes esophagitis, and in more than 50% of cases, a specific radiographic diagnosis can be made because of discrete ulcers without significant plaque formation.

Adult↗
PubMedDate not supplied

Segmental autotransplantation of the distal pancreas to the thigh: CT and ultrasound features.

In select patients with pancreatitis, pancreatectomy may be the only alternative for treatment of abdominal pain. Segmental autotransplantation of the distal pancreas to the thigh has been shown to be successful in preventing or reducing the severity of diabetes following pancreatectomy. We present the postoperative anatomy and potential complications identified on cross-sectional imaging.

Chronic Disease↗
PubMedDate not supplied

Gadolinium-enhanced fat-suppressed T1-weighted imaging of the head and neck: comparison of gradient and conventional SE sequences.

PURPOSE: The purpose of this study was to compare contrast-enhanced GRE and conventional SE (CSE) fat-suppressed T1-weighted techniques in the evaluation of head and neck lesions. A hybrid, opposed phase, frequency-selective, fat-suppressed fast multiplanar spoiled GRE (FMPSPGR) sequence was compared with a fat-suppressed CSE sequence. METHOD: Thirty-two patients with head and neck pathology were evaluated with both fat-suppressed CSE and FMPSPGR sequences. Regions of interest obtained by two viewers in consensus were used to establish contrast-to-noise (CNR) and signal-to-noise ratios for both sequences. Three neuroradiologists also independently reviewed the images for quality of fat suppression, lesion conspicuity, and potential pitfalls. RESULTS: The CNR of the FMPSPGR sequence was superior to that of the fat-suppressed CSE sequence. Subjectively, all three reviewers rated the FMPSPGR sequence as having fat suppression equal to or better than that in the CSE sequence in 94% of cases. Imaging times for the FMPSPGR sequence were 60-75% faster than those for the CSE sequence. CONCLUSION: Enhanced imaging of the head and neck region using an opposed phase, fat-suppressed GRE sequence results in improved fat suppression compared with the CSE technique, with substantial savings in imaging time.

Adult↗
PubMedDate not supplied

Overlooked metastatic lesions of the occipital condyle: a missed case treasure trove.

Radiologic images obtained in nine patients with known primary cancer and occipital or head and neck pain were retrospectively reviewed after having been initially interpreted as normal. Imaging studies included head computed tomography (CT) in five cases, brain magnetic resonance (MR) imaging in six cases, cervical spine CT and MR imaging in five cases, radiography in two cases, and scintigraphy in two cases. This reevaluation demonstrated lesions of the occipital condyles in all patients. Seven patients had unilateral occipital condyle masses, and two patients had bilateral condyle lesions. Lesions were found to either involve only the occipital condyle (n = 4), extend to the adjacent occipital bone (n = 3), or extend to the ipsilateral clivus (n = 2). Misinterpretation of radiologic examinations resulted in an average delay in diagnosis of 10 weeks from the onset of symptoms to definitive therapy (irradiation). It is important to evaluate the occipital condyles in all patients with occipital pain, especially those with cancer. Neoplastic disease involving the occipital condyles is not common; however, it is frequently missed at imaging. Careful review of unenhanced sagittal and axial T1-weighted MR images and of the inferior sections from axial head CT studies will make it possible to avoid this potential pitfall.

Aged↗
PubMedDate not supplied

Sound- and pressure-induced vertigo associated with dehiscence of the roof of the superior semicircular canal.

In many types of peripheral vertigo, imaging is not part of the initial evaluation. We present a patient with sound- and pressure-induced vertigo associated with bony dehiscence of the roof of the superior semicircular canal. The diagnosis of this new entity can only be made by high-resolution coronal CT imaging of the temporal bones. In patients with this symptom complex, CT should be performed early in the diagnostic workup.

Adult↗
PubMedDate not supplied

White matter changes associated with deletions of the long arm of chromosome 18 (18q- syndrome): a dysmyelinating disorder?

PURPOSE: To evaluate the MR findings in the central nervous systems of patients with deletions of the long arm of chromosome 18 (18q- syndrome). METHODS: Sixteen patients with 18q- syndrome ranging in age from 3 to 46 years (mean, 17 years) were studied with high-field-strength MR imaging. Images were analyzed for abnormal T2 hyperintensity in the white matter, abnormal T2 hypointensity in the deep gray matter, and atrophy. RESULTS: Ten of 16 patients had abnormal white matter. Diffuse, bilaterally symmetric deep white matter T2 hyperintensity, most pronounced in the periventricular regions, was most common, noted in eight cases. Focal deep white matter lesions and/or abnormalities involving the subcortical white matter were also noted in four cases. The cerebellum, brain stem, and corpus callosum were spared. Ventriculomegally associated with volume loss, and abnormal T2 hypointensity in the basal ganglia and/or thalami were each present in 11 patients. CONCLUSIONS: The 18q- syndrome is associated with white matter disease and abnormal T2 hypointensity in the deep gray matter. The basis for the white matter abnormalities is unknown, but may be related to one of the two genes for myelin basic protein included in the deleted segment of chromosome 18.

Adolescent↗
PubMedDate not supplied

Use of preoperative MR to predict dural, perineural, and venous sinus invasion of skull base tumors.

PURPOSE: To assess the accuracy of MR imaging in predicting dural, venous sinus, and perineural invasion by skull base tumors. METHODS: The preoperative MR images of 22 patients who had resection of skull base neoplasms were evaluated for the following characteristics: dural enhancement, pial enhancement, local perineural invasion by adjacent tumor, and venous sinus invasion by tumor. The greatest width of dural enhancement was measured, and the character of dural enhancement was noted. The pathologic and surgical reports were reviewed retrospectively with specific attention to dural, venous, and local perineural invasion. RESULTS: Of the 22 patients studied, dural invasion by tumor was confirmed in eight patients, vascular invasion in six patients, and perineural invasion in four patients. The sensitivity of dural enhancement in predicting invasion was 88%, the specificity 50%, and the accuracy 64%. When enhancement and focal nodularity were present, the sensitivity remained at 88%; however, specificity was 100% and accuracy 95%. If the dural enhancement was more than 5 mm thick, sensitivity, specificity, and accuracy were 75%, 100%, and 91%, respectively. Predicting tumor invasion of the dura by the presence of pial enhancement was 50% sensitive and 100% specific. Venous sinus/jugular vein invasion was predicted with 100% sensitivity, 94% specificity, and 95% accuracy. Local perineural invasion was predicted with 100% sensitivity, 50% specificity, and 59% accuracy. CONCLUSIONS: The presence of pial enhancement, focal dural nodules, or dural thickening of more than 5 mm is highly accurate in predicting the presence of neoplastic dural invasion. Linear enhancement of dura does not imply dural infiltration by tumor. Venous invasion by tumor can be predicted accurately with preoperative MR imaging.

Adult↗