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Biomedical subjects

D Rubinstein

Publications and source records attributed to D Rubinstein.

At least 19 recordsLinked to original sources
PubMed2001

Suprasellar cavernous malformation presenting with extensive subarachnoid hemorrhage.

Cavernous malformations are usually intraparenchymal, extra-axial lesions being uncommon. They have very rarely been reported as the cause of subarachnoid hemorrhage. We present a case of hemorrhage related to a cavernous malformation, unusual in two ways. First, it is rare for an intracranial cavernous malformation to present with massive subarachnoid hemorrhage. Secondly, this cavernous malformation lay in the chiasmatic cistern.

Adult↗
PubMed1999

The prevalence and CT appearance of the levator claviculae muscle: a normal variant not to be mistaken for an abnormality.

BACKGROUND AND PURPOSE: The levator claviculae muscle is an infrequently recognized variant in humans, occurring in 2% to 3% of the population, and has rarely been reported in the radiologic or anatomic literature. The importance of this muscle to radiologists is in distinguishing it from an abnormality; most commonly, cervical adenopathy. After discovering this muscle on the CT scans of two patients during routine clinical examinations, we conducted a study to determine the prevalence and appearance of the muscle on CT studies. METHODS: We evaluated 300 CT scans that adequately depicted the expected location of the muscle. The most superior level in which the muscle could be identified and the apparent location of insertion on the clavicle were recorded for all subjects in whom the muscle was detected. RESULTS: Seven levator claviculae muscles were identified in six subjects (2%). It was bilateral in one, on the left in four, and on the right in one. It was identified up to the level of the transverse process of C3 in all cases. The insertion was the middle third of the clavicle for two muscles and the lateral third of the clavicle for the remaining five muscles. CONCLUSION: Because the levator claviculae muscle will most likely be encountered during a radiologist's career, it is important to recognize this muscle as a variant and not as an abnormality.

Cervical Vertebrae↗
PubMed1998

Interobserver reliability of detecting lumbar intervertebral disc high-intensity zone on magnetic resonance imaging and association of high-intensity zone with pain and anular disruption.

STUDY DESIGN: Retrospective analysis of a spine imaging center's records of patients with chronic low back pain referred by tertiary care facilities. OBJECTIVES: 1) To assess the interobserver reliability of detecting lumbar intervertebral disc high-intensity zone on T2-weighted magnetic resonance imaging, and 2) to assess the relation between high-intensity zone and discography or post-computed tomography in symptomatic patients with low back pain. SUMMARY OF BACKGROUND DATA: Two of the three previous studies on this subject found an association between high-intensity zone and the presence of Grade 4 anular disruption with discographic reproduction of patients' exact low back pain. METHODS: Records of patients with low back pain who had undergone lumbar spine discography injection and post-computed tomography from June 1995 to August 1996 were reviewed. Two independent observers were asked to identify the presence of an high-intensity zone from the T12-L1 disc to L5-S1 on T2-weighted magnetic resonance images. With this data, interobserver reliability was assessed with the kappa statistic. Concordant high-intensity zone results were then compared with the Dallas Discogram rating for anular disruption and to patients' subjective pain response to discography injection. With this data, the sensitivity, specificity, and predictive values of high-intensity zone for detecting disc disruption and pain response were calculated. RESULTS: The interobserver reliability for detecting a high-intensity zone in a given disc was fair to good (kappa = 0.57; 95% confidence interval = 0.44, 0.70). The sensitivity of high-intensity zone for detecting Grade 4 anular disruption and exact pain was poor (31%) but its specificity was relatively high (90%). The positive predictive value of a high-intensity zone was low (40%) for a severely disrupted and exactly painful disc. CONCLUSIONS: The interobserver reliability of detecting a high-intensity zone and the positive predictive value of the presence of a high-intensity zone for detecting a severely disrupted and exactly painful disc were much lower than previous studies have shown. The relatively low positive predictive value may be attributable to differences in sample characteristics or procedural variations, or suggest that a high-intensity zone is not indicative of exactly painful internal intervertebral disc disruption.

Adult↗
PubMed1998

Integral and shell-MIP display algorithms in MR and CT three-dimensional models of the brain surface.

BACKGROUND AND PURPOSE: Our purpose was to demonstrate the use of integral and shell maximum intensity projection (shell-MIP) display algorithms in the 3-D CT and MR depiction of cerebral gyral and surface venous anatomy and disorders. These new algorithms are compared against MIP and shaded-surface-display (SSD) algorithms. METHODS: Integral and shell-MIP displays were generated from a specified number of proximal surface voxel layers in a 3-D model. Algorithmic models were compared on nine contrast-enhanced spoiled gradient-recalled acquisition in a steady state (SPGR) MR venograms for brain surface anatomic identification and detail. Seven CT venograms were compared for conspicuity of filling defects. Twelve contrast-enhanced preoperative planning 3-D MR models were rated for neurosurgical utility. RESULTS: A shell-MIP score of 7.00 and an integral score of 6.78 represented the highest mean subjective MR gyral quality (1-10 scale) followed by an SSD score of 3.89 and an MIP score of 1.06. Mean confidence scores for MR central sulcus identification (1-10 scale) were shell-MIP, 7.67; integral, 7.00; SSD, 3.22; and MIP, 1.00. Mean superficial venous quality MR ratings (1-10 scale) were shell-MIP, 8.22; MIP, 7.39; integral, 7.00; and SSD, 3.72. The mean number of cortical veins draining into each side of the superior sagittal sinus on MR was as follows: MIP, 6.19; integral, 6.06; shell-MIP, 5.94; and SSD, 3.81. Mean confidence scores for filling defect identification on CT venograms (1-5 scale) revealed a shell-MIP score of 4.36 and an integral score of 4.29 to be superior to a MIP score of 3.00. In selected cases, 3-D presurgical planning, prior to tumor resection, was clinically useful. CONCLUSION: Integral and shell-MIP are useful 3-D display algorithms for simultaneous display of superficial cerebral veins and gyri on MR images and of thrombosis on CT venograms.

Algorithms↗
PubMed1997

Asymptomatic pontine lesions found by magnetic resonance imaging: are they central pontine myelinolysis?

Clinicians occasionally receive radiographic reports noting pontine lesions in their patients who have undergone magnetic resonance imaging (MRI) for symptoms not referable to the pons. Based on these relatively isolated lesions, patients may receive the presumptive radiographic diagnosis of central pontine myelinolysis (CPM). Review of our MRI database from the last five years identified twelve such patients with hyperintense pontine lesions on T2-weighted scans which were out of proportion to supratentorial white matter disease processes and unexplained by the remainder of their radiographic studies. In an attempt to further clarify whether these findings were more consistent with CPM or some other process, we reviewed these patients' clinical records with particular attention to electrolyte disturbances, alcoholism, liver disease and hypertension. We also compared the MRI studies from these twelve patients with four MRI scans from patients with clinically diagnosed CPM and with eight post-mortem MRI scans on autopsy-proven asymptomatic CPM. By comparing pre- and post-mortem scans, five of the twelve unknown pontine lesions were felt to be too large to represent asymptomatic CPM. Five were thought to be incompatible with CPM based on shape and/or discohesiveness; one of these came to autopsy and showed cerebral and pontine ischemic rarefaction, not CPM. Only two of these twelve cases were felt to be asymptomatic or mildly symptomatic CPM, but have not come to autopsy. We conclude that pontine lesions found incidentally on MRI scans are a heterogeneous group, many of which are more consistent with pontine ischemic rarefaction than with asymptomatic CPM.

Adult↗
PubMed1996

The development of the corpus callosum in semilobar and lobar holoprosencephaly.

OBJECTIVE: The objective of this study was to determine whether and how a true corpus callosum develops in milder cases of holoprosencephaly. MATERIALS AND METHODS: The MR scans of seven patients with holoprosencephaly and a callosum-like structure were reviewed. The anatomy of the callosum-like structure and the pericallosal anatomy were evaluated. RESULTS: Six of the seven cases had a posterior corpus callosum. The seventh case was indeterminate because lack of myelination prevented confirmation that the callosum-like structure consisted only of white matter. In each case the posterior corpus callosum formed posterior to white matter which spanned the interhemispheric fissure beneath a layer of cortical gray matter. CONCLUSION: A posterior corpus callosum can develop in holoprosencephaly because the first callosal axons use the white matter of the undivided hemispheres as a bridge to cross the interhemispheric fissure.

Agenesis of Corpus Callosum↗
PubMed1996

How much does inferior capsular shift reduce shoulder volume?

The purpose of this study was to quantitate the effect of inferior capsular shift on shoulder volume. Four fresh frozen cadaveric shoulders were analyzed. Volume before and after shift was determined using 3 techniques: (1) Magnetic resonance imaging sequences were digitized to computer and analyzed for volume via a 35-mm camera using Cue 2 software. The capsule was delineated by contrast between light and dark regions. Volume was calculated by summing the total area of respective slices. (2) Ultrasound images, obtained after surgical exposure of the capsule, were digitized. Volume was calculated using the formula for a prolate ellipsoid. (3) An 18-gauge needle was used to inject and evacuate saline via an anterior approach. Quantity of aspirated fluid provided a direct measure of volume. Inferior capsular shift was performed. After the operation, measurements were repeated. Inferior capsular shift reduced volume in all shoulders with each technique. On average, inferior capsular shift reduced joint volume by 57 %). A measurable reduction in shoulder joint volume is an effect of capsular shift. This measurement may have clinical application if volume is an indicator of instability or laxity.

Cadaver↗
PubMed1996

Computed tomographic scans of minimally displaced type II odontoid fractures.

OBJECTIVE: To determine the computed tomography (CT) appearance of minimally displaced type II odontoid fractures and the optimal protocols to evaluate these fractures by CT. MATERIALS AND METHODS: The CT scans of five patients with minimally displaced type II odontoid fractures and 71 patients without odontoid pathology were reviewed for signs of fracture. A phantom consisting of a cadaver specimen with a type II odontoid fracture was evaluated with several protocols on four CT scanners. The protocols differed in slice thickness and reconstruction algorithm. Helical scanning was also performed, and parasagittal and coronal reformations were created from each image set. MAIN RESULTS: Multiple cortical disruptions longer than 1 mm were demonstrated on the scans of all five patients with type II odontoid fractures. Only three of the 71 patients without odontoid fractures had multiple cortical disruptions, and none were longer than 1 mm. In the phantom study, thinner sections demonstrated cortical disruptions better than thicker sections. Similarly, images reconstructed with a bone reconstruction algorithm demonstrated the cortical disruptions better than images reconstructed with a soft-tissue reconstruction algorithm. Helical scans (1 mm thick) adequately demonstrated the reduced Type II odontoid fracture. Parasagittal and coronal reformations failed to demonstrate a fracture line through the base of the odontoid process on all image sets. CONCLUSIONS: Cortical disruptions greater than 1 mm and multiple cortical disruptions may be the only findings of odontoid fractures and should suggest the diagnosis. Evaluation of potential type II odontoid fractures is improved as CT section thickness is reduced (down to 1 mm) and is also improved by use of a bone reconstruction algorithm. The apparent absence of a fracture line through the base of the odontoid process on parasagittal or coronal reformations does not rule out the diagnosis.

Cadaver↗
PubMed1996

Gasserian ganglion: appearance on contrast-enhanced MR.

PURPOSE: To characterize the appearance of the gasserian ganglion on contrast-enhanced MR images. METHODS: We retrospectively reviewed the MR images from 57 patients with suspected pituitary disease. These patients had undergone unenhanced and contrast-enhanced MR imaging of the sella, including evaluation of Meckel's cave. None of the patients had clinical signs or symptoms referable to the fifth cranial nerve or ganglion. Correlation was made with a previous study that compared gross anatomy with high-resolution CT scans of cadaveric specimens. RESULTS: A discrete semilunar enhancing structure within the inferolateral aspect of Meckel's cave was identified in 100 of the 114 caves examined; the other 14 caves had a thickened area of enhancement that blended with the dura inferolaterally. A small semilunar structure within the inferolateral aspect of Meckel's cave was also identified on CT scans of the cadaveric specimens. CONCLUSION: The gasserian ganglion enhances on MR images and should not be confused with a pathologic process.

Cavernous Sinus↗
PubMed1995

Subarachnoid neurocysticercosis with occlusion of the major intracranial arteries: case report.

Cysticercosis is the most common parasitic disease affecting the central nervous system. Stroke is a recognized complication of neurocysticercosis, occurring in 2 to 12% of cases, mostly in the form of small lacunar infarcts. We report a case of hemiparesis and aphasia in a 51-year-old Hispanic woman, which was secondary to complete occlusion of the left internal carotid and bilateral anterior cerebral arteries. Magnetic resonance imaging demonstrated the presence of enhancing subarachnoid material surrounding these occluded cerebral arteries, providing antemortem, noninvasive documentation of the inflammatory meningeal cysticercotic reaction that was presumably responsible for the occlusive arteritis causing the cerebral infarction. This represents the third reported case of internal carotid artery occlusion and the first reported case of anterior cerebral artery occlusion secondary to neurocysticercosis.

Brain Diseases↗
PubMed1995

Methanol intoxication with putaminal and white matter necrosis: MR and CT findings.

We report a case of methanol intoxication in which the initial CT scans appeared normal. MR at 4 days showed the typical putaminal lesions of methanol intoxication and, in addition, peripheral white matter lesions that spared a thin rim of subcortical white matter. A CT scan at 17 days showed the putaminal and white matter lesions. The white matter lesions correspond well to lesions previously described in pathologic specimens.

Adult↗
PubMed1995

The anatomy of the inferior petrosal sinus, glossopharyngeal nerve, vagus nerve, and accessory nerve in the jugular foramen.

PURPOSE: To define the variations of the courses of the cranial nerves and the inferior petrosal sinuses as they enter and traverse the jugular foramen. METHODS: Thirty-nine cadaveric specimens containing the jugular foramen were scanned with 1-mm contiguous axial and coronal CT sections. Each specimen was dissected to evaluate the position of the cranial nerves and inferior petrosal sinus as they entered the jugular foramen. RESULTS: The glossopharyngeal nerve entered the most superior, anterior, and medial aspect of the jugular foramen and descended in the anterior portion of the jugular foramen, often within a groove. The vagus and accessory nerves could not be separated by CT. They entered the jugular foramen most often anterior or anterior and inferior to the jugular spine of the temporal bone and descended in a position ranging from medial to anterior to the jugular vein. The inferior petrosal sinus most often coursed inferior to the horizontal portion of the glossopharyngeal nerve and entered the jugular system in the jugular foramen, at the exocranial opening or below the skull base. A pars nervosa and pars venosa could be identified only at the endocranial opening, where the jugular spine separated the pars nervosa containing the inferior petrosal sinus and three cranial nerves from the pars venosa containing the jugular vein. CONCLUSION: Our evaluation demonstrated anatomic variation in the area of the jugular foramen.

Accessory Nerve↗
PubMed1994

Trigeminal nerve and ganglion in the Meckel cave: appearance at CT and MR imaging.

PURPOSE: To demonstrate the anatomy of the Meckel cave, which is normally seen by means of dissection, with high-resolution computed tomography (CT) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: Twenty cadaver specimens were scanned with 1-mm contiguous axial and coronal CT sections. Seven specimens were also scanned with 1-mm contiguous parasagittal sections and were dissected for correlation with CT images. Two volunteers also underwent high-resolution, fast spin-echo MR imaging. MR images were compared with the CT images and the results of dissection. RESULTS: Dissection and CT and MR imaging demonstrated that the trigeminal nerve within the Meckel cave consists of numerous small fibers and that the trigeminal ganglion consists of a small amount of solid tissue. CONCLUSION: In vivo, high-resolution, fast spin-echo imaging can demonstrate the anatomy of the trigeminal nerve in the Meckel cave because of improved spatial and contrast resolution.

Cadaver↗
PubMed1994

Varicella-zoster virus myelitis: an expanding spectrum.

We report four cases of varicella-zoster virus (VZV)-associated myelopathy in adults. Myelopathy was remitting-exacerbating in two remarkable instances, once acute and once chronic. VZV myelopathy was diagnosed based on the close temporal relationship between rash and onset of myelopathy, and for the first time, by polymerase chain reaction, which revealed VZV DNA in the cerebral spinal fluid of three patients with pleocytosis weeks to months later. Magnetic resonance imaging was abnormal in three of four patients. Although all four patients were treated at some time with intravenous acyclovir, concomitant treatment with steroids and the presence of acquired immunodeficiency syndrome in one patient prevented conclusions about a favorable response to therapy. Myelopathy after VZV infection may be remitting-exacerbating in addition to acute or chronic. Detection of VZV DNA in cerebral spinal fluid months after rash was useful for diagnosis and suggests a role for virus in the pathogenesis of myelopathy.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Quantitative contrast-enhanced MR imaging of the optic nerve.

During the acute stages of optic neuritis damage to the blood-optic nerve barrier can be detected using i.v. paramagnetic contrast-enhanced MR imaging. Quantification of the enhancement pattern of the optic nerve, intraorbital fat and muscle was determined in 15 normal subjects using 3 fat-suppression MR imaging methods: T1-weighted spin-echo and spoiled gradient-echo sequences preceded by a fat-frequency selective pulse (FATSAT+SE and FATSAT+SPGR, respectively) and a pulse sequence combining CHOPPER fat suppression with a fat-frequency selective preparation pulse (HYBRID). Pre- and postcontrast-enhanced studies were acquired for FATSAT+SE and FATSAT+SPGR. There was no significant enhancement of the optic nerve by either method (mean increase of 0.96% and 5.3%, respectively), while there was significant enhancement in muscle (mean 118.2% and 108.2%, respectively; p < 0.005) and fat (mean increase of 13% and 37%, respectively; p < 0.05). Postcontrast optic nerve/muscle signal intensity ratios (mean, SD) were 0.51 (0.07), 0.58 (0.05) and 0.75 (0.05) for FATSAT+SE, FATSAT+SPGR and HYBRID, respectively. These results suggest a practical methodology and range of values for normal signal intensity increases and ratios of tissue signal that can be used as objective measures of optic neuritis for natural history studies and treatment trials.

Adipose Tissue↗