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Biomedical subjects

L Wener

Publications and source records attributed to L Wener.

At least 19 recordsLinked to original sources
PubMed2000

Longitudinal study of vascular remodeling in coronary arteries after heart transplantation.

Cross-sectional studies by intravascular ultrasound (IVUS) in heart transplant recipients have suggested that vascular remodeling occurs in coronary arteries years after transplant. However, no reports describe vascular remodeling in the same cohort of patients studied prospectively using morphometric analysis (10 evenly spaced images obtained from a slow pullback from the left anterior descending coronary artery). Morphometric analysis better reflects total vessel anatomy compared with previously reported site (2 to 3 images) analysis. We reviewed 20 patients studied by IVUS at 2 months, 1 year, 2 years, and 3 years after heart transplant.Over time, the coronary artery luminal area decreased from baseline level of 12.0 mm(2) to a 3-year mark of 9.7 mm(2) (p = 0.02). Vessel shrinkage was seen in 16/20 patients. After an initial rise in intimal parameters (maximal intimal thickness, intimal index, and plaque area) from baseline to 1 year, we found a significant decrease in intimal parameters between Year 1 and Year 3 after transplant. For example, plaque area decreased from 2.05 mm(2) at 1 year post-transplant to 1.48 mm(2) by 3 years post-transplant (p = 0.05). In a majority of heart transplant patients, early intimal thickening in the first year post-transplant is accompanied by constrictive remodeling. Over the subsequent 2 years, further constrictive remodeling is seen despite a decrease in intimal area.

Adult↗
PubMed1988

Spinal cord artifacts from truncation errors during MR imaging.

The significance of linear regions of altered signal intensity that appear in sagittal magnetic resonance (MR) images along the length of the spinal cord was investigated. Examinations were performed on ten healthy volunteers and one patient with spinal cord edema. A 0.5-T or a 1.5-T MR system was used. Sampling-related effects (Gibbs phenomenon) at spinal cord edges and cerebrospinal fluid interfaces can lead to different signal patterns within the spinal cord and canal. These artifacts cause problems in interpretation, especially with the use of small object-to-pixel size ratios, by obscuring anatomy and simulating pathologic conditions such as pseudosyringes. Analysis of these intensity variations and of their dependence on sampling may improve the clinical accuracy of MR imaging.

Humans↗
PubMed1988

Association of heterotopic gray matter with seizures: MR imaging. Work in progress.

Heterotopic gray matter, which previously had been associated with severe congenital malformations of the brain and developmental delay, was found without these associated conditions. The authors found ten cases of heterotopic gray matter on magnetic resonance (MR) images. The lesions had a signal intensity that was isointense compared with that of gray matter on T1, spin-density, and T2-weighted images. Nine of the ten cases were associated with a seizure disorder. The tenth case, discovered during a workup for metastatic lung disease, was confirmed with pathologic studies. Heterotopic gray matter is the presence of cortical neurons in an abnormal location, which may be periventricular (nodular) or within the white matter (laminar). A knowledge of heterotopic gray matter and its association with seizures may prevent the misinterpretation of findings on MR images.

Adolescent↗
PubMed1988

Central spinal cord injury: magnetic resonance imaging confirmation and operative considerations.

A case of central cervical spinal cord injury, confirmed by magnetic resonance imaging (MRI) and treated by myelotomy, is presented. After recovering well from his central cord syndrome and walking with assistance, the patient developed a rapidly progressive myelopathy beginning 2 months after injury. His main injury localized clinically to the C8, T1 level; but central cord abnormalities were identified 3 months after injury at the C6 level by MRI: a high signal intensity on the proton density sequence and a low-signal intensity on the T1-weighted sequence. At operation 41/2 months after his injury and 1 month after complete paraplegia, a myelotomy at C6 failed to reveal any cavity (syrinx) but instead disclosed only intense gliosis inside a slightly atrophic spinal cord. Rapid clinical improvement ensued. Secondary syringomyelia may be an endstage condition after spinal cord insults that trigger a progressive, pathophysiological reaction leading to central cord necrosis. In selected cases, myelotomy may interrupt this MRI-identified, nosogenic process before cavitation has occurred.

Adult↗
PubMed1987

MRI in autonomic failure.

A significant rank correlation between rigidity and putaminal signal dropout on magnetic resonance imaging (MRI) in patients with multiple system atrophy suggests that putaminal degeneration may cause this clinical finding. Absence of putaminal abnormalities on MRI in patients with pure autonomic failure may prove useful in differentiating these two autonomic disorders.

Aged↗
PubMed1987

Adrenoleukodystrophy: correlating MR imaging with CT.

The effect on the brain of the sex-linked recessive form of adrenoleukodystrophy was studied in 40 boys, 4-18 years old. All underwent computed tomography (CT) scanning; six underwent magnetic resonance (MR) imaging. MR showed a high sensitivity in demonstrating white matter disease. Auditory pathway disease was characterized as involvement of the lateral lemniscus and medial geniculate body, and visual pathway disease was characterized by lateral geniculate body, Meyer loop, and optic radiation involvement. Contrast-enhanced CT still proved to have a greater capacity (at this time) to show the active, advancing form of the disease and concomitant calcifications. This large CT series also demonstrated the broad and variable expressions of adrenoleukodystrophy, which allowed the unification of previously described atypical forms of the disease.

Adolescent↗
PubMed1986

Multiple system atrophy (Shy-Drager syndrome): MR imaging.

The Shy-Drager syndrome (SDS) is a form of progressive autonomic nervous system failure (PAF) with orthostatic hypotension and associated extrapyramidal involvement that is often mistaken for Parkinson disease. SDS includes olivopontocerebellar atrophy and striatonigral degeneration which is attended by PAF. Eight patients with SDS were studied on a 0.5-T superconducting system utilizing T1-weighted inversion recovery (IR) and T2-weighted spin-echo pulse sequences and also on a 1.5-T system using spin-echo sequences. With IR sequences, atrophy of the putamina was demonstrated in patients with SDS that is consistent with findings of neuronal loss in these nuclei reported on postmortem examinations. An abnormal decrease in signal intensity of the putamina, particularly along their lateral and posterior portions, was also detected, predominantly on T2-weighted sequences, and in three cases on T1-weighted spin-echo sequences. Abnormalities were detected on both imagers but were shown with greater clarity on the 1.5-T device. SDS is the first disease in which convincing basal ganglia changes have been shown in vivo exclusively by MR imaging.

Adult↗
PubMed1977

Computed tomography of spinal cord arteriovenous malformations.

Computed tomography (CT) of the spine after intravenous contrast enhancement has been used in 4 patients with arteriovenous malformation (AVM) of the spinal cord. The enlarged, contrast-filled vessels constituting the malformation are visualized on CT scans. There was good correspondence between CT and selective angiography. CT may be a useful screening and follow-up method for AVM of the spinal cord and a safe procedure for assessing the results of therapy.

Angiography↗