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Biomedical subjects

J C Masdeu

Publications and source records attributed to J C Masdeu.

At least 37 records · Page 2Linked to original sources
PubMed1999

What do neurologists think about their role in neuroimaging training and practice?

In 1996, a survey of the members of the American Academy of Neurology revealed the following facts and opinions: (1) On an average month, each respondent ordered 15 computed tomography, 22 magnetic resonance imaging, 13 ultrasound and 1 single-photon emission computerized tomography studies. (2) Most respondents did not read their own studies for reimbursement, but relied on their own reading for patient management. (3) Respondents felt that neurologists are appropriate specialists to read imaging studies; however, they favored certification for neurologists credentialed in neuroimaging. (4) Organized neurology should provide certification in neuroimaging for neurologists with appropriate training and defend their right and their need to practice neuroimaging, including endovascular procedures.

Diagnostic Imaging↗
PubMed1998

Orthostatic tremor: an electrophysiological analysis.

Orthostatic tremor (OT) is a clinically defined syndrome of leg tremor while standing. Controversy surrounds whether OT is a distinct syndrome or is an essential tremor (ET) variant. We report two patients with OT. Electrophysiological testing included polymyography, accelerometry, nerve conduction, and evoked potential studies. The effects of various maneuvers and body positions on the tremor were assessed. The findings included rapid (15-17 Hz) lower-extremity tremor burst frequency evoked by standing but not by walking or swaying; rapid upper-extremity burst pattern synchronous with lower-extremity bursts; and failure of electrical stimulation or mental concentration to "reset" the tremor. Additionally, there was the novel finding of accelerometric recordings in the legs revealing the same rapid frequency (16-17 Hz) as the electromyographic tremor bursts. Some prior reports have suggested that OT is related to ET by emphasizing a considerable disparity and variability between the accelerometric tremor frequency and the electromyographic burst frequency. In our patients, however, the rapid (15-17 Hz) accelerometer-recorded tremor synchronous with the electromyographic bursts, and also the clinical improvement with clonazepam but not beta blockers or mysoline, and the lack of a family history of ET provide support that OT is distinct from ET.

Aged↗
PubMed1998

Spontaneous resolution of subdural hematoma. MRI findings.

A 33-year-old man suffered a traumatic subdural hematoma with complete spontaneous resolution, as demonstrated by computed tomography scanning and magnetic resonance imaging. After resolution, there was obliteration of the subarachnoid space on the affected side, giving rise to relative dilation of the subarachnoid space over the uninvolved convexity. A resolved subdural hematoma should be considered in the differential diagnosis of such an asymmetry.

Accidental Falls↗
PubMed1998

Discordance between FDG uptake and technetium-99m-HMPAO brain perfusion in acute traumatic brain injury.

A 28-yr-old woman who sustained a mild traumatic brain injury had an 18F-fluorodeoxyglucose (FDG) PET brain study using coincidence imaging performed on a dual-head gamma camera (MCD version; ADAC, Milpitas, CA) followed 24 hr later by 99mTc-hexamethyl propyleneamine oxime SPECT brain perfusion imaging using a triple-head gamma camera (TRIONIX, Twinsburg, OH). The results of the SPECT brain perfusion study demonstrated decreased frontoparietal cortical brain perfusion, whereas 18F-FDG cerebral uptake was normal. Neuropsychological evaluation suggested frontal lobe involvement. This case demonstrates the possibility of discordance between brain perfusion and glucose uptake in acute mild traumatic brain injury.

Adult↗
PubMed1997

Brain single-photon emission CT with HMPAO and safety of thrombolytic therapy in acute ischemic stroke. Proceedings of the meeting of the SPECT Safe Thrombolysis Study Collaborators and the members of the Brain Imaging Council of the Society of Nuclear Medicine.

BACKGROUND: To reliably identify patients at risk for symptomatic hemorrhagic transformation (SHT), future trials of thrombolysis for acute ischemic stroke might use a vascular imaging protocol applicable to a multicenter setting. The goal of this commentary is to address the safety of intravenous thrombolysis with the recombinant tissue plasminogen activator (rTPA) and potential solutions offered by single-photon emission CT (SPECT) as a noninvasive brain perfusion imaging modality. SUMMARY OF REVIEW: Even if patients with severe stroke, extensive ischemic changes on CT scan, advanced age, and high blood pressure are excluded from thrombolytic therapy, this cannot completely guarantee the safety of using rTPA. Brain SPECT scanning with hexamethylpropyleneamine-oxime (HMPAO) may help to screen out patients at risk if performed in addition to clinical and CT tests. The knowledge of pretreatment severity, extent, and location of ischemia might identify good versus poor responders to rTPA therapy. HMPAO-SPECT is widely available and feasible to perform without delaying rTPA therapy. Rigorous quality control and use of reproducible visual and semiquantitative methods of interpreting SPECT are necessary for implementation of SPECT technology in multicenter clinical trials. CONCLUSIONS: The major obstacle to general acceptance of thrombolytic therapies and rTPA in particular is the fear of symptomatic hemorrhagic transformation, and because HMPAO-SPECT might reliably identify patients at high risk of symptomatic hemorrhagic transformation, the clinical value of HMPAO-SPECT in patient selection for thrombolysis during the first hours of acute ischemic stroke should be determined through a prospective clinical trial.

Acute Disease↗
PubMed1996

The open ring. A new imaging sign in demyelinating disease.

Because demyelinating disease of the brain occasionally presents with large ring-enhancing lesions on computed tomography (CT) scans and magnetic resonance images (MRIs), the authors sought to determine whether the ring pattern differed from that found in other common brain lesions with ring enhancement. Published MRI and CT scans of patients with adrenoleukodystrophy (23), and multiple sclerosis or similar demyelinating disorders (21), as well as a variety of tumors (44) and infections (44) matched to the demyelinating lesions by year of publication, in which ring enhancement was evident, were photographed. Photographs without diagnostic identification were presented randomly to two independent observers. The observers rated the contrast enhancement pattern as (1) open ring, with enhancement in the border of the lesion abutting the white matter; (2) closed ring; or (3) uncertain. For all diagnostically certain cases (n = 112), inter-rater agreement was excellent (kappa = 0.75). As an average of the two reviewers, scans for 11 of 132 cases were read as uncertain; 89% of adrenoleukodystrophy cases, 41% of the multiple sclerosis cases, 3% of tumors, and 9% of infections were classified as having the open-ring pattern. Overall, 66% of demyelinating lesions had an open-ring pattern compared with 7% of the non-demyelinating lesions (chi2 = 41.2, p < 0.0001). An open-ring pattern of enhancement is more likely to be associated with demyelinating lesions than with nondemyelinating lesions.

Adrenoleukodystrophy↗