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Biomedical subjects

F R Murtagh

Publications and source records attributed to F R Murtagh.

At least 55 records · Page 3Linked to original sources
PubMed1985

The sinus of the dorsum sellae.

Dissections of cadaver heads and studies of specimens sectioned in horizontal (axial), coronal, or sagittal planes at low (5 X) magnification revealed a frequent venous sinus within the bone of the dorsum sellae in addition to the true dural sinuses. This sinus interconnected the cavernous sinuses on either side of the sella turcica and was continuous with the superior and inferior petrosal sinuses and the basilar plexus. The sinus was quite evident on venograms of five patients. In sagittal sections of 37 adult cadaver heads, the sinus was identified in 28 (76%) and was absent in nine (24%) in which there was pneumatization of the dorsum sellae by the sphenoid sinus. The intracranial sinus of the dorsum sellae is not a true dural sinus but is comparable to the basivertebral veins of the spine.

Cavernous Sinus↗
PubMed1985

Port wine nevus associated with ipsilateral saccular aneurysms: treatment by intraarterial balloon trapping.

A 21-year-old woman with a port wine nevus presented with ipsilateral monocular visual loss. A computed tomography scan of the brain revealed a round suprasellar mass. Angiography demonstrated aneurysm of the right external carotid artery, and petrous, cavernous, and giant ophthalmic internal carotid aneurysms. Four detachable balloons were deployed with arteriographic guidance, resulting in occlusion of the right carotid artery. The association of aneurysms and phakomatoses is discussed. The use of detachable balloons in the treatment of nonresectable aneurysms represents a safe and advantageous option. The use of detachable balloons for carotid occlusion has proven to be an effective modality in the treatment of giant supraclinoid and carotid-cavernous aneurysms. Giant intracranial aneurysms have been surgically treated with carotid ligation proximal to the aneurysm and by direct approach using microsurgical technique. In cases in which direct ligation is not possible balloon occlusion represents an effective alternative. This case illustrates treatment by carotid trapping performed entirely with intraarterial balloons. In addition the association of saccular aneurysms in a patient with a port wine facial nevus is reported.

Adult↗
PubMed1985

Odontoid fracture in a nine-month-old infant.

A type 2 odontoid fracture in a nine-month-old infant is presented. To the best of our knowledge, this case has the youngest reported patient with this type of injury having occurred by a mechanism other than direct trauma at birth. The purpose of this communication is to review odontoid fractures in the pediatric age group.

Axis, Cervical Vertebra↗
PubMed1984

Correlation of hemodynamically significant internal carotid stenosis with pulsed Doppler frequency analysis.

Systolic and mean pressure gradients across internal carotid stenoses were measured at the time of carotid endarterectomy in the arteries of 90 patients, all of whom underwent angiography. Eighty-two of these patients also had pulsed Doppler ultrasonic arteriography with real-time spectrum analysis. There were 71 (79%) high grade stenoses of greater than 50% diameter reduction by angiography. Significant systolic pressure gradients (greater than or equal to 10 mmHg) were identified in 41 patients (46%), 38 (46%) of whom underwent ultrasonic evaluation. A pulsed Doppler frequency measured within the stenosis equal to or greater than 6.5 kiloHertz had a sensitivity of 94.7% (36/38) in identifying pressure reducing lesions with a specificity of 47.7% (21/44). Positive predictive value was 61% (36/59). Angiographic criteria (50% diameter reduction) exhibited a sensitivity of 97.6% (40/41), a specificity of 36.7% (18/49) and a positive predictive value of 56.3% (40/71). Negative predictive value was 94.7% for angiography and 91.3% for ultrasonic arteriography. A pulsed Doppler frequency equal to or greater than 6.5 kiloHertz appears to accurately identify lesions that are at risk to reduce distal internal carotid pressure under operative conditions with a sensitivity similar to angiography. This criterion has a positive predictive value and specificity that is slightly superior to angiography and a high negative predictive value. Pulsed Doppler spectrum analysis provides physiologic information relative to blood flow velocity that is complimentary to the anatomic data provided by angiography for assessing the potential for hemodynamic significance of internal carotid stenoses.

Blood Pressure↗
PubMed1980

Extracranial complications of cerebrospinal fluid shunt function in childhood hydrocephalus.

There were 112 separate hospital evaluations in 84 patients for suspected shunt malfunction: 96 evaluations were of ventriculoperitoneal shunts, 13 were of ventriculoatrial shunts, and three were of both types of shunts. In 45 (47%) of 96 ventriculoperitoneal shunts, complications eventually led to surgical revision; 20 (44%) of these were problems of the peritoneal end and therefore peculiar to this type of shunt. Peritoneal end problems included tubing disconnection, bowel obstruction, perforation, and abdominal cerebrospinal fluid pseudocyst. Of the 13 ventriculoatrial shunts, 10 (79%) required revision; eight (61%) of these were due to problems of the atrial end. These problems included relative shortening of the tubing due to patient growth, superior vena cava thrombosis, and disconnection. Ventriculoperitoneal shunts were used most frequently and had a lower complication rate (47%). Ventriculoatrial shunts were used less often and had a higher complication rate (79%) and more serious problems.

Cerebrospinal Fluid Shunts↗
PubMed1979

Cerebrospinal fluid shunt function and hydrocephalus in the pediatric age group: a radiographic/clinical correlation.

Eighty-four pediatric patients were evaluated clinically and radiographically on 112 separate admissions for suspected increased intracranial pressure and possible shunt malfunction. The shunt system was tested clinically in each patient and correlated with the ventricular size as determined by CT. Of the patients with enlarged ventricles, 87% had an improperly functioning shunt and 13% had a normally functioning shunt. Of the patients with normal or small ventricles, 93% had a normally functioning shunt. Thus the "false negative" rate was 4% (small ventricles with a nonfunctioning shunt) and the "false positive" rate was 13% (large ventricles with a functioning shunt).

Adolescent↗
PubMed1978

Postoperative bony stenosis of the lumbar spinal canal: evaluation of 164 symptomatic patients with axial radiography.

Computed tomography (CT) and transverse axial tomography (TAT) were used to study the lumbar spines of 164 patients with persistent or recurrent low back pain and/or radiculopathy. Of those patients with previous spinal fusion and of those with previous disectomy, 43% and 28%, respectively, demonstrated bony stenosis of the lumbar spinal canal. Of the patients who underwent surgery for this narrowed canal, 91% showed clinical improvement.

Adult↗
PubMedDate not supplied

Thoracic outlet syndrome in a throwing athlete diagnosed with MRI and MRA.

Thoracic outlet syndrome comprises the clinical manifestations in the arm caused by compression of the neurovascular bundle as it leaves the thoracic inlet. The neurovascular bundle is composed of the subclavian artery, the subclavian vein, and the brachial plexus. The symptoms of thoracic outlet or inlet syndrome are most often caused by compression of the nerves of the brachial plexus, which is involved in up to 98% of cases; the remainder are due to vascular compression. MRI with MRA demonstrates well the anatomy of the brachial plexus as well as any vascular compression or occlusion. The relationship of the axillary and subclavian vein to the first rib and subclavius muscle also can be demonstrated. We present a college baseball player who presented with numbness in the fingers of his throwing hand when throwing a baseball. Evaluation with spin-echo and two-dimensional time-of-flight MR angiographic (MRA) imaging of the thoracic outlet region revealed obstruction of the subclavian vein with the arm abducted. To our knowledge, no such cases have been diagnosed previously with MRI.

Adult↗
PubMedDate not supplied

Automatic segmentation of non-enhancing brain tumors in magnetic resonance images.

Tumor segmentation from magnetic resonance (MR) images may aid in tumor treatment by tracking the progress of tumor growth and/or shrinkage. In this paper we present the first automatic segmentation method which separates non-enhancing brain tumors from healthy tissues in MR images to aid in the task of tracking tumor size over time. The MR feature images used for the segmentation consist of three weighted images (T1, T2 and proton density (PD)) for each axial slice through the head. An initial segmentation is computed using an unsupervised fuzzy clustering algorithm. Then, integrated domain knowledge and image processing techniques contribute to the final tumor segmentation. They are applied under the control of a knowledge-based system. The system knowledge was acquired by training on two patient volumes (14 images). Testing has shown successful tumor segmentations on four patient volumes (31 images). Our results show that we detected all six non-enhancing brain tumors, located tumor tissue in 35 of the 36 ground truth (radiologist labeled) slices containing tumor and successfully separated tumor regions from physically connected CSF regions in all the nine slices. Quantitative measurements are promising as correspondence ratios between ground truth and segmented tumor regions ranged between 0.368 and 0.871 per volume, with percent match ranging between 0.530 and 0.909 per volume.

Astrocytoma↗
PubMedDate not supplied

Congested deep subcortical veins as a sign of dural venous thrombosis: MR and CT correlations.

Dural venous thrombosis can have a rapidly progressive fatal course if unrecognized; its clinical picture is often confusing. Numerous CT, magnetic resonance (MR), and angiographic findings have been described to help recognize this entity. We present a case of dilated transcerebral medullary veins as a sign of superior satittal sinus thrombosis with CT and MR correlation.

Aged↗
PubMedDate not supplied

MR imaging of spinal cord hemangioblastoma associated with syringomyelia.

A case of isolated spinal cord hemangioblastoma with associated extensive syringohydromyelia, which was evaluated by myelography, postmyelographic CT, magnetic resonance (MR), and angiography is presented. The specific preoperative and postoperative advantages of MR are given as well as a brief review of the literature.

Adult↗
PubMedDate not supplied

MR evaluation of flow in a ventricular shunt phantom with in vivo correlation.

The ability of magnetic resonance (MR) imaging to potentially distinguish areas of fluid in motion from areas of static fluid would seem to make it possible to differentiate functioning ventriculoperitoneal shunts from non-functioning shunts in hydrocephalic patients. To test this hypothesis, a standard adult ventricular shunt system including tubing and flow control valve was tested and imaged in vitro in a flow phantom on a 1.5 T magnet with flow rates of 0, 22, 1.00, 0.50, and 0.25 ml/min. A flow void sign was present in the flow control valve on mildly and heavily T2-weighted images at all four flow rates and absent when the flow rate was 0 ml/min. In addition, we were able to image a flow void sign in the flow control valve of a patient with a functioning ventricular shunt, as well as to demonstrate absence of the flow void sign in the flow control valve in a patient with an obstructed ventricular shunt. This data suggest that MR imaging of the flow control valve in patients with ventricular shunts could yield valuable information on shunt patency.

Adolescent↗