PubMed Health⌕ Search

Biomedical subjects

D W Chakeres

Publications and source records attributed to D W Chakeres.

At least 37 records · Page 2Linked to original sources
PubMed1989

Magnetic resonance imaging and clinical correlates of intellectual impairment in myotonic dystrophy.

Although intellectual impairment is common in patients with myotonic dystrophy, this aspect of the disease has received relatively little research attention. We examined 41 patients with myotonic dystrophy using objective neuropsychological procedures and magnetic resonance imaging. Ten patients (24%) had severe and generalized intellectual dysfunction, while lesser or no cognitive impairment characterized the remaining patients. Degree of intellectual impairment was not related to neuromuscular status or sex. Patients with severe intellectual disturbance had significantly earlier onset of both myotonia and weakness and were more likely to inherit the disease from their mother. Magnetic resonance imaging findings indicated that while degree of cerebral atrophy was not related to severity of intellectual impairment, skull thickness, focal white matter lesions, and anterior temporal lobe abnormalities were significantly more common in patients with severely disturbed intellect. This study reports a number of previously unreported cerebral magnetic resonance imaging findings associated with intellectual impairment in myotonic dystrophy, but the etiology of these changes awaits neuropathologic examination.

Adolescent↗
PubMed1989

Magnetic resonance imaging in dementia of Parkinson's disease.

The possibility that dementia in Parkinson's disease is associated with specific cerebral abnormalities identifiable by magnetic resonance imaging (MRI) was examined. Sixty eight patients with Parkinson's disease and 28 age and education matched normal controls were evaluated using neuropsychological procedures that included assessment of language, memory, cognition, visuospatial skills and mood. Twenty three patients (34%) were found to have developed significant impairment in at least three of the five areas, thus meeting criteria for a dementia syndrome. Eleven patients (16%) had no intellectual impairment and thirty four patients (50%) had a mild to moderate intellectual disturbance. Patients with (n = 10) and without dementia (n = 20), matched for severity of Parkinson's disease, and normal controls (n = 10) matched for age with the two patients groups, were evaluated by MRI. MRI scans were analysed for evidence of generalised cerebral atrophy, ventricular enlargement, visualisation of the substantia nigra and severity of focal brain lesions. Results indicated that the presence of dementia in patients with Parkinson's disease was not associated with any specific pattern of MRI abnormalities.

Adult↗
PubMed1989

MR imaging artifacts of the axial internal anatomy of the cervical spinal cord.

Transverse scans of the spinal cord routinely demonstrate signal variations related to the internal anatomy of the cord that do not accurately conform to histologic cross sections. This study evaluates the MR appearance of the axial anatomy of the spinal cord and provides correlation to histologic sections as a means to understand this discordance so that disease can be recognized more readily. Short TR/TE spin-echo studies, cardiac-gated multiecho spin-echo studies, and gradient-refocused-echo studies of normal excised human spinal cords, a normal volunteer, and gelatin phantoms were obtained by using the same imaging parameters at 1.5 T. Imaging artifacts were further investigated by using both a 128 x 256 and 256 x 256 matrix with a varying phase-encoded axis. Histologic sections of the excised cords, which were stained for myelin, iron, and cell bodies (Nissl), were used for correlation to the images. We found that significant Fourier truncation and partial-volume imaging artifacts modulated the MR display of the cord. On short TR/TE images a ring of high signal at the periphery of the cord was due to a truncation artifact. The appearance of the central portions of the gray and white matter was affected variably by partial-volume averaging depending on the matrix size. White-matter tracts of the cord were always lower in signal than was the gray matter on all pulse sequences. This finding was not due to iron deposition or CSF motion artifacts. We suspect that this probably was related to dense, longitudinal organization of spinal tracts and resultant anisotropy of water molecule motion similar to that seen in the pyramidal tracts, tendons, and ligaments. We recommend the use of a 128 x 256 matrix with two averages (four excitations) when obtaining axial scans of the spinal cord in living subjects. Although truncation artifacts diminish image quality, the quality is superior to that of images obtained with a 256 x 256 matrix, in which longer scanning times result in motion artifacts and reduced signal to noise.

Humans↗
PubMed1989

Magnetic resonance imaging of pituitary and parasellar abnormalities.

The ease, safety, accuracy, reliability, specificity, and sensitivity of the diagnosis of disorders of the sellar region all have been enhanced by MRI. This article demonstrates the normal anatomy and the wide array of pathology that can be visualized by MRI. Magnetic resonance has become the imaging modality of choice for most of the disorders within and about the sella.

Adenoma↗
PubMed1989

Computed tomography and magnetic resonance imaging of the normal anatomy of the temporal bone.

The high image quality provided by current high resolution CT bone algorithms in conjunction with the multiplanar and soft tissue imaging capabilities of MRI, provide exquisite anatomic detail of the temporal bone structures. This allows the radiologist to visually dissect this complex, three-dimensional structure, if a firm understanding of normal anatomy exists. In this way, the pathological processes involving the temporal bone can be better understood and correlated with the clinical setting.

Cerebellopontine Angle↗
PubMed1988

Evoked potentials in chronic inflammatory demyelinating polyneuropathy.

Eighteen patients with chronic inflammatory demyelinating polyneuropathy were studied with evoked potentials to assess for evidence of central nervous system demyelination. Both visual and brain-stem auditory evoked responses were obtained, and the results were compared with magnetic resonance imaging (MRI). An evoked potential was abnormal in nine of 18 patients, five of whom had central nervous system evidence of demyelination by MRI. Evoked potentials identified four patients with probable anterior optic pathway involvement that was not demonstrable by MRI. These findings continue to support that chronic inflammatory demyelinating polyneuropathy is associated with a central demyelinating disorder and more importantly emphasize the possibility of a common pathogenic mechanism in central and peripheral nerve demyelination.

Brain Stem↗
PubMed1987

Magnetic resonance imaging of uveal melanomas.

A series of 31 patients who presented with uveal mass lesions was studied with magnetic resonance imaging (MRI). Uveal melanoma was the presumed clinical diagnosis in 23 of the cases. Ten (43%) of these suspected melanomas provided useful images on both spin-lattice (T1)- and spin-spin (T2)-weighted studies and these had characteristic features. The features include a high-intensity image on T1-weighted studies with progressively decreasing relative intensity on T2-weighted images. These findings are consistent with short T1 and T2 relaxation times. In contrast, three cases of carcinoma metastatic to the choroid demonstrated a relatively high signal intensity on both T1- and T2-weighted images. The short relaxation times exhibited by uveal melanomas are in contrast with the relatively long T1 and T2 times found in other malignant neoplasms. These characteristics may provide a noninvasive method for differentiation of malignant melanoma from other mass lesions within the uveal tract.

Humans↗
PubMed1987

Tumors of the osseous spine: staging with MR imaging versus CT.

Twelve patients with tumors involving the osseous spine were evaluated with magnetic resonance (MR) imaging and computed tomography (CT), six with and six without intrathecal injection of contrast material. MR imaging was found to be superior to CT without contrast material and equal to CT with contrast material in delineating the anatomic relationships of the tumors, including bone involvement, spinal canal invasion, paraspinal soft-tissue extension, and vascular involvement. Since MR imaging can provide most of the anatomic information necessary for treatment planning, intrathecal injection of contrast material can be avoided in most instances when evaluating tumor involvement of the osseous spine. However, CT without contrast medium was superior to MR imaging in showing critical cortical bone destruction and calcified tumor matrix.

Humans↗
PubMed1987

Evidence for central nervous system demyelination in chronic inflammatory demyelinating polyradiculoneuropathy.

It is unclear whether sporadic reports of concurrent multiple sclerosis (MS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) represent coincidence or whether these two demyelinating disorders are pathogenically related. We utilized the sensitivity of magnetic resonance imaging (MRI) in detecting central nervous system (CNS) lesions to investigate 16 patients with CIDP. Six of the 16 had periventricular, subcortical, and brainstem white matter lesions indistinguishable from those seen in MS. Three of these patients had definite clinical and laboratory evidence of MS; three others with abnormal MRIs had no findings indicative of CNS disease. Previous reports have indicated that a significant number of MS patients have peripheral nerve demyelination. Our study suggests that many CIDP patients have concurrent CNS demyelination. Taken together, these observations support the existence of a central-peripheral inflammatory demyelinating syndrome. Whether this combined demyelinating syndrome lies on a spectrum between MS and CIDP or is a separate pathogenic entity will require further investigation.

Adult↗
PubMed1987

Hybrid color MR imaging display.

A novel computer-image processing method is described that combines and displays the data from two different MR sequences of the same anatomic slice in a single color image. The pixel intensities from one image are assigned varying spectral hues while the luminance of these hues is derived from the intensities of corresponding pixels of a second spatially aligned image. This technique provides a two-dimensional resolvable contrast scale that may produce images of improved information content. The versatility of the method, termed hybrid color display, is demonstrated by using T1-weighted, T2-weighted, chemical-shift, and gradient-recalled-acquisition-into-steady-state (GRASS) images. This technique may facilitate MR interpretation by enhancing anatomic and pathologic conspicuity and by expediting review.

Color↗
PubMed1986

Flexed sitting maneuver for complete lumbar myelography in patients with severe spinal stenosis and apparent block.

A new technique has been designed to improve myelography examinations of the entire lumbar spinal canal in patients with severe spinal stenosis using a single needle puncture. When a high-grade obstruction to the caudal flow of contrast material is encountered, the patient is placed in a flexed sitting position for 1 minute. This technique was performed in eight patients with severe lumbar spinal stenosis. It successfully helped depict the lower lumbosacral canal below an apparently complete block in four patients and resulted in improved visualization of the lower sac in four patients with partial block.

Humans↗
PubMed1985

Radiology of the ambient cistern. Part I: Normal.

The angiographic and high-resolution, thin-section CT appearance of the normal ambient cistern is correlated with anatomic dissections and sections of normal, formalin-fixed cadaver brains. Each of three separate anatomic segments of the ambient cistern--the supratentorial segment, the tentorial edge and the subtentorial segment--has a characteristic CT appearance that can be correlated with specific vascular structures on routine angiography.

Cerebral Angiography↗
PubMed1985

Computed tomography of the ossicles.

Otologists and otolaryngologists have described in detail the disorders which are unique to the ossicles. However the anatomy and spectrum of pathology of the ossicles are not familiar to most radiologists. Recent advances in computed tomography (CT) and a systematic approach to evaluation now allow accurate identification of even subtle abnormalities of the ossicles. We present the normal anatomy, ossicular abnormalities, and indications for computed tomographic study. Because of the greater diagnostic capability of CT, the radiologist's role has increased in evaluation and treatment planning of patients with suspected ossicular abnormalities.

Cholesteatoma↗
PubMed1985

Computed tomographic evaluation of non-metallic middle-ear prostheses.

Non-metallic middle-ear prostheses, including a plastipore total ossicular replacement prosthesis (TORP) and partial ossicular replacement prosthesis (PORP), a Teflon loop stapes piston, and a Ceravital PORP were used to reconstruct the ossicular chain in formalin fixed cadaver temporal bones. The temporal bones were examined using high resolution, thin-section computed tomographic techniques identical to those used for patient studies. The detail and resolution of the images were comparable with those obtained on standard patient exams. The temporal bones were evaluated to determine the appearance of the prostheses in normal and abnormal positions within the middle ear. The radiologist examined the images without fore-knowledge of the position of the prostheses and was able to accurately identify both normal and abnormal positions. With the proper technique an accurate evaluation of non-metallic middle-ear prostheses is possible by high-resolution computed tomography.

Cadaver↗
PubMed1985

Soft-tissue abnormalities of the external auditory canal: subject review of CT findings.

We review the normal anatomy and discuss characteristic findings of soft-tissue abnormalities of the external auditory canal (EAC). The indications for computed tomography (CT) of the temporal bone have been significantly expanded with the inclusion of soft-tissue abnormalities of the external ear and the auditory canal. Soft-tissue abnormalities of the EAC that can be evaluated with CT include atresia, edema, hemorrhage, fracture, posttraumatic or infection-caused keloid, malignant external otitis, hemangioma, lymphangioma, papilloma, keratosis obturans, acquired cholesteatoma, adenoma, ceruminoma, fibroma, mixed tumor, sarcoma, and basal cell, squamous cell, or adenocystic carcinoma. CT scans of 25 patients who had soft-tissue abnormalities of the EAC were reviewed. The clinical data were correlated with the radiographic findings. We conclude that CT is the best overall radiographic modality for evaluating the extent and character of soft-tissue abnormalities of the EAC. Significant clinical information that is helpful in patient management decisions is added by this technique.

Adenoma↗
PubMed1985

Computed tomography of the ethmoid sinuses.

CT scanning of the ethmoid sinuses is a significant advancement in the diagnostic evaluation of patients with pathology in this region. It allows for simultaneous and accurate evaluation of fine bony detail as well as subtle soft tissue abnormalities.

Ethmoid Bone↗
PubMed1984

Meckel's cave epidermoid with trigeminal neuralgia: CT findings.

An epidermoid tumor of Meckel's cave was found in a middle-aged woman with trigeminal neuralgia. On CT the lesion had negative attenuation numbers of fat and extended from an expanded Meckel's cave through the porous trigeminus into the ambient and cerebellopontine angle cisterns. Surgical excision provided relief of the patient's trigeminal neuralgia.

Brain Neoplasms↗