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L D DeWitt

Publications and source records attributed to L D DeWitt.

33 records · Page 2Linked to original sources
PubMed1988

Benign disappearance of ventricular thrombus after embolic stroke. A case report.

The source for a patient's middle cerebral artery territory embolic stroke was found by echocardiography to be a left ventricular cardiac thrombus. The apical mass was large, pedunculated, and moved with systole into the ventricular cavity. The absence of ventricular dyskinesia was thought to favor a tumor, and surgery was considered before repeat echocardiography showed disappearance of the mass, making thrombus the likely diagnosis. No further embolic events occurred during or since the disappearance of the thrombus while on anticoagulation therapy. Serial echocardiography for change in or disappearance of a ventricular mass may be critical in distinguishing thrombus from tumor.

Aged↗
PubMed1988

Transcranial Doppler.

TCD recording of flow velocities in intracranial vessels was first described by Aaslid in 1982. The utility of this instrument becomes more apparent as it is used in different clinical settings and compared with angiographic findings (Figures 1 and 2). Its importance in early detection of vasospasm in subarachnoid hemorrhage is now clearly known; increased flow velocity can be documented prior to neurologic deterioration and thus allow early institution of therapy. In patients with stroke or transient ischemic attack of unclear etiology, especially in blacks, Orientals, or females, who have a higher incidence of intracranial arterial disease, TCD can be a very important noninvasive means for detecting stenosis of intracranial vessels. Its value for assessing collateral circulation, intraoperative monitoring, and measuring CBF is quite promising. Hopefully, through further work with TCD, we will be able to clarify the spectrum of its usages as well as its limitations, though the preliminary data indicate that it should be an important addition to present noninvasive evaluations.

Arterial Occlusive Diseases↗
PubMed1988

Dissection of the intracranial vertebral artery.

We describe four patients and review prior reports to clarify the clinical, radiographic, and pathologic findings of intracranial vertebral artery (VA) dissection. A 43-year-old man and a 33-year-old woman had chronic bilateral VA dissecting aneurysms. The man had multiple episodes of subarachnoid hemorrhage (SAH) and necropsy showed multiple dissections and defects in the internal elastica. The woman had many brainstem TIAs and strokes during 3 years. Two other patients had SAH and unilateral dissections. Intracranial VA dissection causes four overlapping syndromes: (1) brainstem infarcts are usually due to subintimal dissection extending into the basilar artery, affect younger patients, and often are single fatal events; (2) SAH is due to subadventitial or transmural dissection; (3) aneurysms cause mass effect on the brainstem and lower cranial nerves; and (4) chronic dissections due to connective tissue defects cause extensive bilateral aneurysms and repeated TIAs, small strokes, and SAH.

Adult↗
PubMed1987

Posterior cerebral artery stenosis.

We analyzed the clinical features of symptomatic posterior cerebral artery (PCA) stenosis in 6 patients selected from 15 patients with angiographically documented PCA atherostenosis occurring during a 7-year period. Transient ischemic attacks (TIAs) were the major presentation in 5 patients. A homonymous visual field defect was present in 2 patients. TIA symptoms were predominantly visual or sensory, or both. The most common visual symptom was difficulty seeing to one side. One patient saw flashing lights. Sensory spells were always paresthetic, usually involving the arm and hand and occasionally the face and leg. Three patients had visual and sensory spells together. Two patients with a visual field defect had calcarine infarcts found by computed tomography. All patients were treated with warfarin. During follow-up (4 months to 4 years), no patient had a new stroke in the PCA territory, and only one continued to have TIAs. PCA atherostenosis is rarer then PCA embolic occlusion. In contrast to those with PCA embolism, our patients with PCA atherostenosis had more TIAs and fewer infarcts. The clinical features of PCA stenosis--preponderance of visual and sensory TIAs--distinguish this vascular lesion from stenosis of the middle cerebral artery.

Aged↗
PubMed1985

MRI and the study of aphasia.

Three-dimensional magnetic resonance imaging (MRI) was used to study various aphasia and neurobehavioral syndromes due to embolic or thrombotic cerebral infarction. Two patients are presented to illustrate how MRI may complement, and sometimes improve on, CT for the in vivo demonstration of anatomic changes underlying said syndromes. MRI images were reconstructed at planes selected to match CT, and at coronal planes through the entire anteroposterior extent of the lesions. Both CT and MRI detected lesions; however, MRI provided better differentiation of gray and white matter. Coronal reconstructions aid in optimally visualizing the relationship of lesions to the opercular and perisylvian gyri. CT may be inadequate to define actual extent of lesions, whereas MRI may more clearly show that apparently subcortical lesions can, in fact, involve the cortex as well.

Adult↗
PubMed1985

Anticoagulant-related intracerebral hemorrhage.

Twenty-four patients had intracerebral hemorrhage while they were being treated with anticoagulants. Hypertension was present in 67% of the cases, head trauma was an uncommon preceding event, and simultaneous bleeding in other organs occurred in only one instance. Neurologic abnormalities progressed for several hours in 58%. Seizures occurred at onset in 12.5%. The location of the hemorrhage was as follows: cerebellum (nine cases), lobar white matter (six), basal ganglia (five), thalamus (two), and hemisphere, unspecified (two). In 61%, the hemorrhages occurred within 6 months of therapy. In 75%, the prothrombin time was beyond 1 1/2 times the control value. Mortality was 62.5%. Survivors had smaller hematomas than did patients with fatal hemorrhage.

Adult↗
PubMed1984

Nuclear magnetic resonance imaging in evaluation of clinical stroke syndromes.

Proton nuclear magnetic resonance (NMR) imaging was performed on normal volunteers and patients with various types of clinical strokes. True three-dimensional volumetric data were obtained for subsequent reconstruction of images at various orientations, including transverse, coronal, and sagittal, and for specific matching to x-ray computed tomographic planes. A variety of radiofrequency pulse sequences was used to generate images weighted by the NMR parameters spin density (p) and spin-lattice (T1) and spin-spin (T2) relaxation times. Quantitative T1 data and qualitative T2 information were obtained from appropriate sequences. Proton NMR images embodying T1 information provided adequate delineation of normal intracranial anatomical structure and a high level of gray matter-white matter contrast; high lesion detection sensitivity in various clinical forms of stroke was seen in images providing both T1 and T2 information. T1 and T2 relaxation times were prolonged in embolic, thrombotic, and watershed infarctions as well as in lacunae; shortening of T1 and T2 was found in hematomas. Serpiginous vessels in an arteriovenous malformation were seen that had particular pulse sequences.

Cerebellar Diseases↗
PubMed1984

Central pontine myelinolysis: demonstration by nuclear magnetic resonance.

An alcoholic, hyponatremic woman developed central pontine myelinolysis (CPM) and improved from a decerebrate, comatose state to alertness and full ambulation. NMR, using inversion-recovery and spin-echo pulse sequences, was performed sequentially from 4 weeks to 8 months after onset of symptoms and revealed a well-defined lesion with prolonged relaxation times. The lesion was anatomically consistent with CPM and was initially also visualized by CT. NMR showed no definite temporal change in the qualitative appearance of the lesion until the 8-month scan; however, quantitatively, a reduction of relaxation times was noted with each serial study.

Adult↗
PubMed1983

Nuclear magnetic resonance imaging in central nervous system disease.

From the preliminary work of many investigators, it appears that proton nuclear magnetic resonance (NMR) imaging will have wide application in the diagnostic assessment (and potential management) of patients with vascular, neoplastic, and demyelinating diseases of the central nervous system (CNS). Findings in isolated cases and small series suggest that NMR imaging may play a role in the evaluation of patients with other CNS conditions including hydrocephalus, malformations, infections, developmental and metabolic disorders, and degenerative processes. Because of the dynamic nature of disease processes involving the CNS, the precise meaning of NMR image parameters (rho, T1, and T2) remains unclear. A comprehensive study correlating NMR images in neurologic disease with precise neuropathologic examination is required. In the future, with accurate quantitative measurements of these NMR parameters, in vivo imaging may provide insight into the dynamic nature of neurologic disease.

Central Nervous System Diseases↗
PubMed1983

Periodic nonalternating ocular skew deviation accompanied by head tilt and pathologic lid retraction.

A 60-year-old black male with a 13-year history of adult onset diabetes mellitus and hypertension with a previous lacunar stroke suddenly developed a periodic head and eye movement disorder characterized by nonalternating skew deviation, rotatory nystagmus, head tilt, and lid retraction. On CT scan, the patient had a lacunar infarct in the right midbrain in the region of the interstitial nucleus of Cajal, an anatomical area involved with head tilt, torsional eye movement, and skew deviation.

Cerebral Infarction↗
PubMedDate not supplied

Vertebral-basilar posterior cerebral territory stroke--delineation by proton nuclear magnetic resonance imaging.

We used three-dimensional proton NMR images to study ischemic infarction in the territory of the vertebral-basilar posterior cerebral circulation. The study includes sixteen cases, eight of which are presented in detail. In seven cases, the infarctions were secondary to demonstrable large artery occlusive disease -- vertebral, basilar, or posterior cerebral. In nine cases, the infarctions were secondary to what was presumably small vessel disease. In fifteen of the sixteen cases, NMR imaging could locate the infarct, inversion recovery and spin-echo pulse sequences being more sensitive than the saturation recovery pulse sequence. This efficiency rests on the high sensitivity of ischemic infarction to changes in T1 and T2 relaxation time, highlighted in the inversion recovery and spin-echo images, respectively. The additional advantages of the three-dimensional approach, and the lack of bone artifact, make NMR imaging superior to CT scanning in identifying areas of infarction in the territory of posterior cerebral circulation.

Adult↗
PubMedDate not supplied

Clinical use of nuclear magnetic resonance imaging in stroke.

There are many positive aspects to the use of MRI in the evaluation of cerebrovascular disease. First, the MR imaging technique appears to be essentially without hazard. It does not rely on ionizing radiation, and no intravenous injections of contrast agent are necessary. MRI exploits the tissue's inherent biophysical characteristics to provide superior contrast. Infarctions are well delineated by MRI, often better and earlier than CT. Because of the lack of MRI signal from bone and thus the lack of transverse artifact from bone often seen with CT, lesions in the posterior fossa are very well visualized. With MRI it is possible to obtain images in the transverse, coronal, and sagittal planes, which provides for good evaluation of lesion size and extent. Arteriovenous malformations have been visualized by MRI, but it is still too early to know whether MRI has any detection capability over CT in this disorder. Subdural hematomas have been well visualized by MRI, including cases of isodense subdurals not visualized by CT. On the other hand, MRI has not proven to have any advantage over CT in the evaluation of intracerebral hemorrhage, hemorrhagic infarction, and subarachnoid hemorrhage. In fact, for detection of intracerebral hemorrhage and subarachnoid hemorrhage, CT may be better at the present time. In chronic infarction the surrounding area of Wallerian degeneration may cause the area of infarction to appear larger than it actually is. Hopefully, with further research into the use of different pulse sequence techniques and with good neuropathological correlation, the present limitations of MRI can be eliminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Malformations↗
PubMedDate not supplied

NMR-neuropathologic correlation in stroke.

True, three-dimensional proton nuclear magnetic resonance imaging at 0.147 tesla was performed postmortem on 2 patients embodying various stroke syndromes, including chronic (4 and 15 years) infarction, subacute (within 1 week) bland infarction, acute (2 days) hemorrhagic infarction, and hematoma secondary to ruptured aneurysm. A third patient, with subcortical arteriosclerotic encephalopathy, so-called Binswanger's disease, was examined antemortem using a 0.6 tesla scanner. Nuclear magnetic resonance images were reconstructed at levels matching the pathologic specimens. Qualitative and, when available, quantitative comparisons between the results of nuclear magnetic resonance imaging and pathology were carried out. Areas of qualitatively prolonged T1 and T2 relaxation times on nuclear magnetic resonance imaging were more extensive than the corresponding areas of chronic infarction noted pathologically and were determined to be infarcts plus the adjacent areas of Wallerian degeneration. Hemorrhagic infarction, without evidence of blood on computed tomography, was found to have mildly prolonged T1 and T2 relaxation times, between those of normal brain and chronic infarction; a 10-day-old hematoma had a very short T1, slightly shorter than that of white matter, and a mildly prolonged T2, with values between those of white and gray matter. Subcortical arteriosclerotic encephalopathy was found to have areas of prolonged T1 and T2 relaxation times involving almost the entire white matter of the corona radiata.

Acute Disease↗