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Biomedical subjects

A Yeates

Publications and source records attributed to A Yeates.

10 recordsLinked to original sources

Altered venous function and deep venous thrombosis following proximal femoral fracture.

The effect of surgery for femoral neck fracture on lower limb venous blood flow and its relationship to deep vein thrombosis was investigated in 179 patients. Blood flow was measured using strain gauge plethysmography before surgery, in the 1st week after surgery, and at 6 week review. There was a significant reduction in both venous outflow and venous capacitance, affecting both fractured and non-fractured legs but significantly greater in the fractured leg. Venous function remained significantly impaired in both lower limbs 6 weeks after surgery. There was a significant correlation between the reduction in venous function and the development of deep vein thrombosis.

Aged↗

Changes in coagulability as measured by thrombelastography following surgery for proximal femoral fracture.

The effect of surgery for femoral neck fracture on whole blood coagulation and the relationship of altered coagulation to deep venous thrombosis were investigated in 250 patients. Whole blood coagulation was measured using thrombelastography preoperatively, in the early postoperative period and at 6-week review. Significant hypercoagulability was demonstrated after surgery and persisted to 6-week review. A significant correlation between hypercoagulability and the development of deep venous thrombosis is demonstrated. Hypercoagulability is shown to be a major factor in thrombosis formation following proximal femoral neck fracture surgery.

Aged↗

Intra-arterial digital subtraction angiography of the spinal cord.

Digital subtraction angiography (DSA) of the spinal cord was performed in 6 patients using selective intra-arterial injections of contrast material. Two arteriovenous malformations of the spinal cord, 1 dural fistula, and 1 case of multiple hemangioblastomas were studied. Contrast and spatial resolution were satisfactory for defining normal and abnormal vascularity while reducing examination time, contrast dosage, patient discomfort, and film cost. The only significant limitation was misregistration artifacts seen on lateral views encompassing the diaphragm.

Adult↗

Cryptic vascular malformations involving the brainstem.

Six patients with angiographically cryptic vascular malformations involving the brainstem were examined with computed tomography (CT). The clinical and CT findings of cryptic vascular malformations of the brainstem are described and distinguished from those of brainstem glioma and multiple sclerosis. Calcification within a brainstem lesion that displays relatively little mass effect and shows little contrast enhancement, particularly when associated with a long history of waxing and waning brainstem symptoms, should suggest a vascular malformation.

Adult↗

Magnetic resonance imaging of the spinal cord and canal: potentials and limitations.

Preliminary experience with magnetic resonance imaging (MRI) of the spinal cord and canal in 17 patients indicates considerable promise in the diagnosis of neoplastic, degenerative, and congenital lesions. The ability to image the cord directly rather than indirectly as in myelography, the absence of bone artifact as in computed tomography, and the multiplanar capabilities indicate that MRI will be the procedure of choice in the examination of the spinal cord. Current limitations include partial-volume effects due to slice thickness and the inability to perform contiguous sections when using multiplanar techniques. The relative increase in signal from cerebrospinal fluid with long TR and TE sequences in spin-echo imaging may result in less sensitivity than in the brain for detection of cord edema and/or infarction.

Humans↗

An intraventricular arachnoid cyst.

The computed tomographic appearance and the differential diagnosis in a case of unusual congenital intraventricular arachnoid cyst are presented.

Adult↗

Nuclear magnetic resonance imaging of syringomyelia.

Five patients with syringomyelia were examined with a 3.5 kG nuclear magnetic resonance (NMR) imager. Syrinx cavities were visualized in all five cases, and image quality compared favorably with metrizamide computed tomography (CT). Axial images were optimal for identifying syrinx cavities, and sagittal views were useful in providing an overview of cord morphology and in examining the craniocervical junction. Inversion-recovery images were less valuable than the spin-echo sequences. By varying spin-echo imaging parameters, tissue relaxation times could be determined and the fluid nature of the syrinx cavities confirmed. This limited study suggests that NMR may challenge the current role of CT in the diagnostic workup of syringomyelia.

Diagnosis, Differential↗

Examination of the extracranial carotid bifurcation by thin-section dynamic CT: direct visualization of intimal atheroma in man (Part 2).

Examination of the extracranial carotid bifurcation by thin-section computed tomographic (CT) scans after bolus, high-volume contrast enhancement allowed detection of more disease than did arteriograms in six of eight consecutive patients with transient ischemic attacks. In four patients this was on the clinical side of the lesion; in two the disease was in the asymptomatic carotid artery. One patient appeared to show a carotid ulcer; the ulcer was detected on CT. However, at surgery and subsequent histology, the surface of the lesion was endothelialized. The carotid CT examination is performed in the scanner "dead time" between unenhanced and enhanced head CT scans using the same contrast material for both studies. The examinations covers 3-3.6 cm of the carotid bifurcation region. Thin-section CT of the extracranial carotid arteries is a noninvasive examination that on preliminary evaluations appears to have sensitivity at least equal to that of carotid angiography in the detection of intimal disease.

Adult↗

Opacification of epidural venous plexus and dura in evaluation of cervical nerve roots: CT technique.

Thin-section computed tomography (CT) after bolus high-volume, intravenous contrast enhancement of the cervical epidural and intervertebral foraminal venous plexus was undertaken in eight patients. Visualization of exiting cervical nerve root by opacification of the surrounding intervertebral plexus was evaluated in 38 foramina. Visualization was judged as excellent in 77% and good in 21%. Thus the nerves were seen satisfactorily in all but one foramen. As the CT scan parallels the long axis of the cervical roots as they pass through the intervertebral foramen, anatomic delineation of the root out to the level of the vertebral artery is excellent. A local widening of the root, which was thought to represent the dorsal root ganglion, was seen in most foramina examined. Excellent filling of the epidural plexus was seen in seven of eight subjects; good opacification was seen in the other subject. In no instance did the study fail to satisfactorily fill the epidural plexus in the cervical vertebral canal. This technique appears to be an excellent method for evaluating the cervical nerve roots and the epidural space.

Cervical Plexus↗