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Biomedical subjects

R A Hyman

Publications and source records attributed to R A Hyman.

53 records · Page 3Linked to original sources
PubMed1975

The cervical aortic arch anomaly.

Although the cervical aortic arch anomaly occurs rarely, it should always be considered in the differential diagnosis of pulsatile masses in the neck. The eighteenth case of this anomaly is presented herein. Review of the previous literature demonstrates the consistent pattern of branching anomalies associated with the cervical aortic arch and indicates the complex nature of this anomaly. Studies of these patients in biplane (frontal and lateral), as well as the right posterior oblique projection in order to precisely define the order of branching, is recommended, particularly when surgical intervention is indicated.

Aorta, Thoracic↗
PubMedDate not supplied

Axis selection in transverse magnetic resonance imaging of the brain: electronic angulation techniques.

The cylindrical design of most head coils utilized with current magnetic resonance (MR) imaging units and the necessity of close approximation of the coil to the head to maximize signal-to-noise ratio precludes flexion or extension of the head to any significant degree during of imaging of the brain. For this reason, the canthomeatal line is approximately parallel to the standard transverse magnetic axis. Standard computed tomography (CT) scans in the transverse plane are usually obtained at an approximately 25 degrees angle to Reid's baseline (RBL). This leads to projection differences in viewing and comparing standard transverse MR and CT studies. High convexity lesions which may present anteriorly on a given CT section may present posteriorly on an MR section which appears to be at a comparable level on first inspection. Secondly, one or more transverse MR sections usually display a portion of the occipital lobes behind the cerebellar hemispheres. The region of the tentorium and straight sinus can occasionally give rise to a vermiform appearance (the "AVM artifact"). Thirty patients were studied with MR at a 20-30 degrees angulation to RBL without any loss of image quality and with excellent visualization of the posterior fossa. The effect of transverse axis change on lesion position was demonstrated in five high convexity lesions and by utilizing fixed brain specimens. While clearly MR can accurately localize lesions utilizing orthogonal multiplanar techniques, it is suggested that investigators and clinicians currently performing MR studies of the brain consider potential advantages of electronic angulation techniques for comparative clinical studies and certain research applications.

Brain↗
PubMedDate not supplied

Even echo MR rephasing in the diagnosis of giant intracranial aneurysm.

Blood flow magnetic resonance (MR) imaging has played a significant role in the evaluation and differentiation of vascular from nonvascular lesions, particularly as it applies to the CNS. Even echo rephasing and high velocity signal loss are two phenomena that are useful in differentiating primary vascular lesions that exhibit either slow laminar flow or rapid flow from solid masses or clot-containing vascular lesions. Application of these two basic principles of blood flow imaging with MR aided in establishing the correct diagnosis in a case of giant intracranial aneurysm.

Aged↗
PubMedDate not supplied

Congenital spondylolisthesis of the 6th cervical vertebra: CT findings.

The CT demonstration of a case of congenital spondylolisthesis of the C6 vertebral body is reported. This entity includes bilateral bony defects in the pars interarticularis regions, deranged facet joints, as well as a midline bony cleft in the spinous process. This congenital deformity should be recognized and not mistaken for traumatic spondylolisthesis.

Adult↗
PubMedDate not supplied

Total myelography in the evaluation of lumbar discs. With the presentation of three cases of thoracic neoplasms simulating nerve root lesions.

It has been our practice to perform total myelography in all cases of lumbar disc disease including the various syndromes of spinal stenosis, because experience has indicated that myelographic abnormalities in the cervical and thoracic areas could have clinical importance despite the presence of gross changes in the lumbar region. Failure to establish a definite diagnosis by restricted lumbar myelography makes it mandatory to evaluate all levels of the spinal axis. Recently, 3 patients with thoracic spinal cord tumors presented with primary signs and symptoms of lumbar spine disorders. Evidence of spinal cord disease was minimal and could be readily overlooked. Total myelography disclosed varying degrees of lumbar spinal pathology, but also showed evidence of lesions in the thoracic region. One proved to be an intramedullary astrocytoma of the spinal cord, and two were schwannomas. The symptoms of low-back pain and lumbar radiculopathy improved after excision of the schwannomas and following x-ray therapy and chemotherapy in the patient with the intramedullary neoplasm.

Adult↗
PubMedDate not supplied

Evaluation of the lumbar spine in patients with glycogen storage disease: CT demonstration of patterns of paraspinal muscle atrophy.

CT studies of the lumbar spine were performed in 19 patients with glycogen storage disease. Nine of 10 patients with McArdle's disease and seven of nine patients with acid maltase deficiency demonstrated posterior paraspinal muscle atrophy out of proportion to their ages. In addition, the psoas muscles were spared in all 10 patients with McArdle's disease and were involved with atrophy in seven of the nine patients with acid maltase deficiency. We conclude that when patients with low back pain-or asymptomatic patients-demonstrate otherwise unexplained atrophy of the paraspinal muscles the diagnosis of glycogen storage disease should be considered. Furthermore, when the psoas muscles are spared, the specific diagnosis of McArdle's disease is suggested.

Adipose Tissue↗
PubMedDate not supplied

Fat within the falx: MR demonstration of falcine bony metaplasia with marrow formation.

Falcine bony metaplasia frequently is incorrectly labeled "dense calcification" on brain CT and conventional radiography. Of 3,000 brain magnetic resonance (MR) scans reviewed, 12 demonstrated a central area of increased signal intensity on T1 and T2 weighted images with a smooth peripheral rim of diminished signal intensity within the region of the falx. The central area of increased signal intensity corresponded to fat in the medullary cavity and the peripheral area of low signal intensity corresponded to cortical bone. The CT scans, available in nine of 12 patients, were compared with the MR scans and revealed dense mineralization in the corresponding region of the falx. A postmortem specimen of densely "calcified" falx cerebri was examined that revealed cortical bone and a medullary cavity complete with bony trabeculae and marrow. The MR findings of falx ossification should not be confused with other entities of greater clinical significance.

Adipose Tissue↗
PubMedDate not supplied

0.6 T MR imaging of the cervical spine: multislice and multiecho techniques.

During a 6 month period, 50 patients with signs and symptoms referable to the cervical spine were studied with a 0.6 T superconducting magnetic resonance (MR) imaging unit. The last 23 of these 50 patients were studied with combined multislice and multiecho techniques. In 38 of the 50 patients, abnormalities were demonstrated on MR images. Intramedullary lesions included syringomyelia (three cases), primary tumors (two), metastatic neoplasm (one), cord atrophy secondary to trauma (one), and multiple sclerosis (one). Intradural, extramedullary lesions included two neurofibromas and two Chiari malformations. The rest of the lesions were extradural: degenerative changes (10), spinal stenosis with cord compression (five), disk degeneration and/or herniation (five), postoperative changes (four), metastases to bone/epidural disease (three), and neurofibromatosis (one). Two patients had more than one abnormality. The MR findings were compared with available routine radiographs, computed tomographic (CT) scans with and without metrizamide, and myelograms. MR imaging was consistently better than routine CT scanning in the detection of lesions of the spinal cord and in directly imaging the effects on the spinal cord of extrinsic abnormalities such as spinal stenosis. Metrizamide-enhanced CT scanning detected all cases of syringomyelia, but it involved an invasive procedure. Myelography alone was slightly less sensitive and considerably less specific than MR in detecting intramedullary lesions and in distinguishing cord neoplasms from syringomyelia. Multislice, multiecho techniques with up to 240 msec echo times (TEs) were particularly helpful in the detection and characterization of extradural processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗