Biomedical subjects

V M Haughton

Publications and source records attributed to V M Haughton.

At least 91 records · Page 5Linked to original sources

PubMed1993

Lumbar cribriform fascia: appearance at freezing microtomy and MR imaging.

Axial T1-weighted magnetic resonance (MR) images and exactly corresponding sections obtained with freezing microtomy of cadaveric lumbosacral spinal columns were compared to describe the MR appearance of the cribriform fascia within the neural foramen. On anatomic sections, the cribriform fascia was identified as a thin sheet of tissue in the lateral neural foramen. On MR images, the cribriform fascia appeared as a thin band of low signal intensity, which contrasted with the high-signal-intensity epidural fat. The cribriform fascia is another landmark in the neural foramen that can be identified with MR imaging.

Fascia↗

PubMed1993

MR imaging of the sacral plexus: normal findings.

Imaging of the sacral plexus requires evaluation of both intradural and extradural components with cross-sectional techniques. Although CT is useful, individual extradural sacral nerves and the sacral plexus usually cannot be distinguished from adjacent structures. The higher contrast resolution provided by MR imaging allows the region of the sacral plexus to be examined in greater detail. With MR imaging, the constant relationship of the neural components to one another, and the gluteal vessels in their course from the sacrum to the greater sciatic foramen, can be shown consistently. An understanding of the anatomy of this area in multiple planes can aid in more accurate localization of abnormalities involving the sacral plexus. This pictorial essay reviews the MR appearance of the region of the sacral plexus.

Cadaver↗

PubMed1993

Focal hyperintensities in cerebral white matter on MR images of asymptomatic volunteers: correlation with social and medical histories.

OBJECTIVE: Previous attempts to explain the presence of focal hyperintensities in the cerebral white matter on MR images have focused on the patient's age and cardiovascular risk factors. The purpose of this study was to survey many variables in subjects' social, medical, and surgical histories to identify those factors associated with focal hyperintensities in asymptomatic persons. SUBJECTS AND METHODS: Asymptomatic volunteers were examined with MR imaging of the head and questioned concerning smoking history; chemical dependence; alcohol consumption; medical history (e.g., high blood pressure, kidney disease); surgical history (e.g., for appendix, gallbladder); medications (e.g., antihypertensives, analgesics); and other historical family and social variables. Vital signs were recorded. Focal hyperintensities were counted by observers who were not provided any information about the subjects other than that they were either volunteers or patients. Each of the variables in the history was tested for an association with the number of focal hyperintensities seen on MR images. RESULTS: A statistically significant positive association was found between both age and the use of antihypertensive medications and the number of focal hyperintensities. Associations were also found between the number of focal hyperintensities and diastolic and systolic blood pressures at the time of MR imaging, but these associations did not reach statistical significance. No other variables in the medical, surgical, or social histories were found to be significantly related to the number of focal hyperintensities. CONCLUSION: Age and the use of antihypertensive medications were the only significant risk factors identified in respect to focal hyperintensities of the cerebral white matter.

Adult↗

PubMed1992

Quantitative MR in the diagnosis of multiple sclerosis.

In patients with multiple sclerosis (MS), the apparently uninvolved cerebral white matter between demyelinated plaques may have biochemical abnormalities. To what degree the changes in the white matter contribute to symptomatology in MS is unknown. In 39 patients with multiple sclerosis, and in 39 age-matched nondiseased volunteers, T1 and T2 were calculated from spin-echo images in four regions of apparently uninvolved white matter. In three of four white matter areas, the average T1 and T2 were significantly longer in the patients than in the controls. The T1 correlated with the disability, measured by the Kurtzke Extended Disability Status Scale, although the correlation was marginally significant. The results suggest that in patients with MS, white matter disease that is not visualized in MR as distinct foci of abnormal signal intensity may contribute to disease burden and disability.

Brain↗

PubMed1992

Visualization of the distal intratemporal facial nerve with MR imaging: use of an oblique plane.

Although magnetic resonance (MR) imaging routinely is used to evaluate the facial nerve, the conventional axial, coronal, and sagittal planes are not optimal for demonstrating the tympanic and mastoid portions of the nerve. A vertical oblique plane for MR imaging of these portions of the facial nerve was evaluated. With this plane, the course of the nerve was effectively demonstrated on MR images and corresponding cryosections. The oblique plane can be used to supplant or supplement conventional planes in imaging of the facial nerve.

Facial Nerve↗

PubMed1992

Proximal lumbar spinal nerves in axial MR imaging, CT, and anatomic sections.

The proximal lumbar spinal nerve is composed of a group of small fascicles interspersed with fat. These fascicles converge into the ventral ramus. The authors studied the appearance of this portion of the spinal nerve through analysis of magnetic resonance (MR) images, computed tomographic (CT) scans, and exactly corresponding anatomic sections in cadavers. The fascicles can be identified at MR imaging or CT as poorly defined structures surrounded by the fat lateral to the neural foramen. The ventral ramus appears as a pair of oval, contiguous, small homogeneous structures. The evaluation of nerve compression may be aided by identification of the fascicles and ventral rami on CT and MR images.

Adult↗

PubMed1992

Neural foraminal ligaments of the lumbar spine: appearance at CT and MR imaging.

Axial and parasagittal computed tomographic (CT) scans and magnetic resonance (MR) images and exactly corresponding sections obtained with the freezing microtome in 18 human cadavers were examined to characterize the radiologic appearance of the lumbar neural forminal ligaments, which have been thought to contribute to nerve root compression. In the CT component of this study, 114 neural foramina at 57 spinal levels were studied; in the MR component, 27 neural foramina were studied. The ligaments originated from the posterolateral margin of the intervertebral disk and attached to the inferior pedicle, superior articular process, transverse process, or ligamentum flavum. On CT scans, they appeared as linear structures with higher attenuation coefficients than those of the adjacent fat and areolar tissue; on MR images, as linear structures with lower signal intensities than those of the adjacent fat and areolar tissue in the neural foramina. It is concluded that the ligaments in the neural foramen can be effectively depicted with CT or MR imaging.

Adult↗

PubMed1992

Proximal cervical spinal nerve: MR appearance.

An interradicular cleft and a segment of nerve containing fascicles have recently been described in the cervical spinal nerve. This study was performed to determine whether the fascicles and the interradicular cleft have a distinctive appearance on magnetic resonance (MR) images. The proximal spinal nerves and nerve roots of C-4 and C-8 were removed from cadavers, imaged with MR, sectioned, and stained. Cervical neural foramina were imaged with MR and then sectioned. The MR images demonstrated a division of the root sheaths into ventral and dorsal portions, separated by fat within the interradicular cleft and located proximal to the dorsal root ganglion. Distal to the dorsal root ganglion, the proximal portion of the cervical spinal nerve containing multiple fascicles gave the proximal portion of the spinal nerve an inhomogeneous appearance on the MR images. This study suggests an anatomic explanation for the variable appearance of the cervical spinal nerves with MR imaging.

Aged↗

PubMed1992

Three-dimensional time-of-flight MR angiography with a surface coil: evaluation in 12 subjects.

We compared three-dimensional time-of-flight MR angiograms obtained with head coils and then with surface coils in five patients with intracranial vascular lesions and in seven normal volunteers to determine if imaging of intracranial vascular anatomy could be improved with the use of a surface coil. Visualization of small peripheral vessels was consistently better with a surface coil than with a head coil at identical small fields of view (FOVs). The surface-coil technique allowed small-FOV imaging of peripheral vascular lesions with higher spatial resolution and signal-to-noise ratio similar to that of large-FOV head-coil images. The use of a surface coil introduced the problem of signal falloff; centrally located vessels were visualized as well or better when a standard head coil was used. We conclude that surface-coil MR angiography can serve as a useful adjunct to routine head-coil MR angiography in the evaluation of peripheral vascular abnormalities.

Angiography↗

PubMed1992

High-signal foci on MR images of the brain: observer variability in their quantification.

Foci of high signal in the cerebral white matter are common incidental findings on MR images of the brain of control subjects or patients with a variety of diseases. Although the number of foci has been reported to correlate with age and several risk factors, the degree of observer variability in quantifying foci has not been reported. We used kappa statistics to determine radiologists' agreement in counting high-signal-intensity foci on MR images obtained in healthy volunteers and in patients with hypertension. Before interpreting the images, one pair of radiologists studied 30 routine MR images and reached consensus on differentiating high-signal foci from other foci of high intensity caused by normal structures (e.g., deep gyri or Virchow-Robin spaces). These two observers than independently determined the number of foci in the study group. Using their own criteria, other radiologists independently counted the foci. Agreement between observers was determined with the kappa statistic. The results showed fair agreement between the radiologists who first reached a consensus in counting foci of hyperintensity and poor agreement between the other observers. We conclude that in order to compare the frequency of foci of hyperintensity in different groups of patients, observer variability must be controlled. Studies without proper control subjects may lead to incorrect conclusions regarding the correlation of focal hyperintensities and various risk factors.

Alzheimer Disease↗

PubMed1991

A new plain film finding in cysticercosis.

Lytic lesions of the skull due to cysticercosis are described. Encysted larvae in the subarachnoid space eroded the inner table of the skull in a 10-year-old Guatemalan male. In an area with endemic cysticercosis infections, this diagnosis should be considered when round, lytic defects are demonstrated in a skull radiograph.

Bone Diseases↗

PubMed1991

Effect of lidocaine on the meninges in an experimental animal model.

Arachnoiditis has been reported in patients who had received previous epidural injections of anesthetic agents. The purpose of this study was to determine if epidural injections of lidocaine are sufficient to cause arachnoiditis. Four monkeys that received a single epidural injection of lidocaine hydrochloride 1% were compared to four controls that had epidural injections of 0.9% saline. Four dogs that had multiple epidural injections of lidocaine hydrochloride 1% were compared to four controls that had multiple injections of saline. All animals were killed on the eighty-fourth day of the experiment. The dural sac, containing nerve roots and spinal cord, was removed intact from the lumbar spinal canal, fixed, sectioned, stained, and examined microscopically for evidence of arachnoid inflammation and fibrosis. No significant changes were found in the treated animals. Lidocaine hydrochloride 1% injected singly or repeatedly in the epidural space does not appear to be a cause of significant chronic meningeal reaction.

Animals↗

PubMed1991

Traumatic facial injuries with steering wheel loading.

This study was conducted to evaluate the biomechanics of facial fractures caused by steering wheel loading. Twelve intact fresh human cadaver heads were impacted onto standard or energy-absorbing steering wheels with a custom-designed and validated vertical-drop apparatus. Either zygoma was impacted once at a velocity of 2.0-6.9 m/s. The specimens were oriented to permit a direct comparison between pretest and posttest radiography, and two-dimensional and three-dimensional CT images. Bone mineral content was determined, and biomechanical forces, accelerations, and deformations were recorded. More severe fractures were associated with higher forces on the zygoma. With increasing velocities, fractures initiated at the zygomatic region propagated to other unilateral regions such as the mandible and orbit or to the contralateral side. Less facial trauma was observed with energy-absorbing steering wheels compared with standard wheels at similar impact velocities. Bone mineral content did not correlate well with specimen age or with fracture severity. Clinically significant fractures were identifiable on 3-D CT images. The flexibility of 3-D CT in evaluating the spatial extent of facial abnormalities in different orientations may have significant impact in planning surgical procedures.

Accidents, Traffic↗

PubMed1991

Multiple sclerosis: specificity of MR for diagnosis.

The specificity of magnetic resonance (MR) imaging in the diagnosis of multiple sclerosis (MS) has not been measured systematically. Conventional MR head images with sagittal localizer and axial multiple-echo sequences with long repetition times were obtained in 92 patients with clinically verified MS (Schumacher criteria), 100 healthy volunteers, 60 subjects with hypertension, and eight patients with dementia. Two readers, without the aid of any clinical or demographic information, classified each of the 260 studies as MS or not MS. The readers classified the studies again after being supplied with the subjects' ages and sex. True-negative and true-positive diagnoses of MS were tabulated. The specificity of the MR diagnosis of MS (true-negative results in proportion to all non-MS studies) was 95%-99% with all the control groups included. There is a small risk of misinterpreting incidental periventricular white matter foci as plaques of MS in MR studies.

Adult↗

PubMed1991

Lumbar spinal nerves in the neural foramen: MR appearance.

The appearance of the proximal lumbar spinal nerves at magnetic resonance (MR) imaging has not, to the authors' knowledge, been described. MR images and exactly corresponding sections obtained from four cadavers by means of a freezing microtome were correlated to characterize the MR appearance of the proximal spinal nerves. The junction of the dorsal and ventral rami with the dorsal and ventral roots consists of a group of six to 15 fascicles measuring 2-6 mm in length. These fascicles appear in MR images obtained with short repetition times as small foci of lower signal intensity than that of surrounding fat. The proximal spinal nerve and its relationship to the intervertebral disk and osseous margins of the neural foramen can be demonstrated effectively with MR imaging.

Aged↗

PubMed1991

T1 and T2 in the cerebrum: correlation with age, gender, and demographic factors.

The authors measured the T1 and T2 of cerebral tissue in 164 volunteers aged 5-90 years and correlated T1 and T2 with age, gender, and various demographic variables. A weak correlation with statistical significance was found between age and T1 and T2 in white and gray matter structures. The T1 and T2 in the telencephalon increased by about 0.1% per year. No correlation of T1 or T2 with any other demographic, life-style, or medical factors was found.

Adolescent↗

PubMed1991

Multicenter study of gadodiamide injection as a contrast agent in MR imaging of the brain and spine.

To evaluate the safety and efficacy of gadodiamide injection, a nonionic gadolinium chelate complex, in magnetic resonance (MR) imaging of the head and spine, a phase II-III trial was conducted in 439 patients with known or suspected lesions in the central nervous system. All patients received gadodiamide injection in a dosage of 0.1 mmol/kg and were monitored; MR images were evaluated for contrast material enhancement. No serious adverse events or clinically important trends in vital signs, laboratory values, or neurologic status were observed. Gadodiamide injection enhanced or facilitated the visualization of lesions in 266 or 353 patients (75.4%) in whom lesions were shown on unenhanced images, enhanced images, or both; in these 266 patients, the diagnosis was changed in 76 patients (28.6%) and facilitated in 190 patients (71.4%). It is concluded that gadodiamide injection is safe and effective for MR imaging of the head and spine in patients with suspected abnormalities of the central nervous system.

Brain↗

PubMed1991

Articular cartilage: correlation of histologic zones with signal intensity at MR imaging.

Zones of high and low signal intensity on magnetic resonance (MR) images of articular cartilage were correlated with the four histologic zones normally found in such cartilage. Grossly normal articular cartilage from knees and ankles of a fresh cadaver were used in the study. The three zones identified on MR images included a low-intensity zone near the articular surface, a zone of higher signal intensity next to that, and a second zone of low intensity that was deep to the two others. The location of the superficial low-intensity zone corresponded to dense, tangentially oriented layers of collagen in the superficial histologic zone. Higher signal intensity deep to the superficial low-intensity zone correlated with cartilage in the transitional zone. The deep low-intensity zone correlated with a combination of deep radiate and calcified cartilage and cortical bone. Results of this study indicate that, with high resolution, MR imaging may demonstrate three zones of differing signal intensity in articular cartilage. The superficial low-intensity zone may be a useful marker of the surface of normal articular cartilage.

Ankle Joint↗