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Biomedical subjects

M M Mishkin

Publications and source records attributed to M M Mishkin.

At least 19 recordsLinked to original sources
PubMed1997

Chiari I malformation: association with seizures and developmental disabilities.

Chiari I malformation, a congenital abnormality in which deformed cerebellar tonsils are displaced downward through the foramen magnum, commonly presents in patients with headache or symptoms of dysfunction of the cerebellum, brain stem, and cervical spinal cord. We report 11 children with Chiari I malformation who presented with seizures and developmental delay in motor or language function with or without autistic features. To our knowledge, an association between Chiari I malformation and seizures or neurodevelopmental deficits or both has not been previously reported. We believe that Chiari I malformation should not be considered an incidental finding in these patients, but may be a marker for subtle cerebral dysgenesis. Chiari I and II malformations may constitute a complex but continuous spectrum, related to the timing and severity of a shared underlying embryologic mechanism.

Arnold-Chiari Malformation↗
PubMed1995

MR imaging: quality assessment method and ratings at 33 centers.

PURPOSE: To outline a quality assessment method with peer review for magnetic resonance (MR) imaging. MATERIALS AND METHODS: Thirty-three providers in the Philadelphia area were rated on a random sample of 132 brain, 124 cervical spine, and 113 lower extremity MR imaging examinations performed during 1990. Blinded peer review was performed by panels of three subspecialty-trained academic radiologists. Technical performance, completeness, and report appropriateness of each MR imaging examination were evaluated. Aggregated scores were calculated to rate provider performance for each of the three parameters of quality. RESULTS: Two or three panelists assessed technical performance as inadequate in 15 cases, completeness as incomplete in 58 cases, and the interpretative report as inappropriate and affecting treatment in 72 cases. Eleven providers received an unsatisfactory rating on one or more parameters of quality. The association between unsatisfactory ratings and the use of low-field-strength (< or = 0.6-T) imagers was statistically significant (P < .008). CONCLUSION: Substantial deficiencies were identified in the performance of examinations and interpretation of MR images in the Philadelphia area in 1990. These findings indicate the need for a program to monitor quality of MR imaging.

Brain↗
PubMed1994

Blinded-reader comparison of magnetic resonance angiography and duplex ultrasonography for carotid artery bifurcation stenosis.

BACKGROUND AND PURPOSE: We compared two-dimensional time-of-flight magnetic resonance angiography (MRA) and duplex ultrasonography with arteriography for the detection of 70% to 99% stenoses at the carotid artery bifurcation (ie, surgical disease according to findings of the North American Carotid Endarterectomy Trial). METHODS: Three blinded readers independently measured stenoses on MRA in 73 vessels from 38 patients. Duplex ultrasonography was available in 66 vessels from 35 of these patients, and blinded reading was performed by one reader. Comparison was made to arteriography. RESULTS: Magnetic resonance angiography demonstrated a sensitivity of 92.4%, specificity of 74.5%, and negative predictive value of 95.8% for 70% to 99% stenoses. Interobserver agreement was high (kappa = 0.91). Absence of signal at stenoses with evidence of distal flow usually, but not always, corresponded to surgical disease. Duplex ultrasonography demonstrated a sensitivity of 81.0%, specificity of 82.2%, and negative predictive value of 90.2% for surgical disease. There was no significant difference between MRA and duplex ultrasonography for the sensitivity or specificity in detecting 70% to 99% stenoses (P > .1, exact form of the McNemar test). MRA had no false positives or false negatives for complete occlusions of the carotid artery, whereas duplex ultrasonography missed one occlusion and falsely called two patent vessels occluded. In seven cases, both MRA and duplex ultrasonography overestimated stenoses to miscategorize them as surgical disease. CONCLUSIONS: Although the sensitivity and specificity of MRA and duplex ultrasonography are not significantly different for distinguishing surgical and nonsurgical degrees of stenosis at the carotid bifurcation, MRA has some advantages that may make it the screening test of choice. Concordant MRA and duplex ultrasonography for surgical disease does not necessarily obviate the need for catheter arteriography.

Aged↗
PubMed1994

Pretreatment with corticosteroids to prevent adverse reactions to nonionic contrast media.

OBJECTIVE: The purpose of this study was to determine whether patients receiving a two-dose corticosteroid regimen before IV injection of nonionic contrast medium gain protection against adverse reactions to contrast material. SUBJECTS AND METHODS: A randomized, blinded study involving three institutions was initiated in 1988. Patients were divided into two groups. One group received a 32-mg oral dose of methylprednisolone administered 6-24 hr before and again 2 hr before injection of contrast material. The other group received placebo tablets administered in the same time periods. During a 3-year period, 1155 patients and control subjects successfully completed the protocol. Demographic characteristics, including histories of previous reactions and histories of asthma or allergy, did not differ in the two groups. All signs and symptoms that appeared after injection of contrast material were carefully recorded and graded according to an earlier scheme [1]. Patients, control subjects, and all attending personnel were blinded regarding the premedication. RESULTS: Corticosteroid pretreatment conferred protection for overall reactions (1.7% vs 4.9%, p = .005) and grade I (mild) reactions (0.2% vs 1.9%, p = .004). Subjects receiving corticosteroids also had fewer grade II (moderate) (p = .63) and grade III (severe) (p = .11) reactions, but the total numbers involved were small, and the differences were not significant. CONCLUSION: A rigidly controlled study of the potential protective effects of a two-dose oral corticosteroid regimen preceding IV injection of nonionic contrast medium indicates that corticosteroid pretreatment confers significant protection, at least for overall reactions and grade I reactions.

Administration, Oral↗
PubMed1991

Comparison of the rates of adverse drug reactions. Ionic contrast agents, ionic agents combined with steroids, and nonionic agents.

The influence of ionic agents alone, of diatrizoate plus two oral doses of methylprednisolone premedication, and of a nonionic agent (iohexol) upon the frequency and severity of adverse drug reactions (ADRs) was compared in ten hospitals during three separate time periods from 1985 to 1989. Nonionic agents were found to reduce significantly total ADRs; 52 of 8857 patients receiving nonionic agents experienced reactions, versus 263 of 6006 patients for ionics (P less than .0001). The frequency of reactions classed as mild (2.9% for ionic agents versus 0.476 for nonionic agents: P less than .001), moderate (1.2% versus 0.1%; P less than .001), or severe (0.37% versus 0.01%; P less than .001), also favored nonionic agents. Steroid premedication provided some protection, but iohexol was significantly better with respect to mild reactions (2.9% versus 0.4%, P less than .001), moderate reactions (0.9% versus 0.1%, P less than .01), and severe reactions (0.25% versus 0.01%, P less than .01). The contrast medium was the greatest risk factor for adverse reaction (odds ratio 7.3), while prior contrast reaction (odds ratio 6.25), and hay fever (odds ratio 2.3) were found to be significant independent risks. We conclude that nonionic agents are safer for intravenous use than ionic agents given alone or with corticosteroid premedication.

Diatrizoate Meglumine↗
PubMed1991

Enhanced resolution of pituitary fossa by three-dimensional fat-suppressed gradient-echo magnetic resonance: before and after gadolinium enhancement.

In imaging small anatomical parts such as the pituitary fossa, thin sections enhance the spatial resolution. Gradient recalled images (GRASS) using three-dimensional volume data produce ultrathin contiguous sections with a high signal-to-noise ratio. In this study, conventional spin-echo magnetic resonance images (MRIs) of the pituitary fossa were compared to three-dimensional gradient recalled MRI in 5 volunteers and 10 patients suspected of having pituitary gland abnormalities. Utility of fat suppression was also assessed, along with gadolinium enhancement. Conventional spin-echo and three-dimensional spoiled GRASS images, three-dimensional spoiled GRASS images without and with fat suppression (Group II), and three-dimensional spoiled GRASS images with fat suppression before and after gadolinium enhancement were compared. Three-dimensional spoiled GRASS images provided better delineation of the pituitary fossa structures. There was differential enhancement between the normal gland and pituitary tumors. The fat suppression technique following gadolinium administration helped separate the high signal of tumor from the high signal of the clivus marrow. In conclusion, T1-weighted three dimensional gradient-echo images with fat suppression following gadolinium enhancement appear promising in evaluation.

Adenoma↗
PubMed1991

Past, present, and future of radiology of meningioma.

The evolution of the radiologic findings associated with meningiomas represents a microcosm of the evolution of diagnostic radiology that has occurred since the discovery by Röntgen of the x-ray beam in 1895 and the founding of the Radiological Society of North America in 1915. What will the next new, as yet unimagined, imaging modality contribute to our current ability to detect and diagnose these lesions? No one can forecast this, but it should prove to be both fascinating and challenging.

Brain Neoplasms↗
PubMed1991

Contrast media.

This article reviews the most recent papers on contrast media reported from October 1989 to September 1990. Areas of focus include water-soluble contrast agents and barium agents.

Contrast Media↗
PubMed1990

Contrast media safety: what do we know and how do we know it?

Use of an intravenous injection of a water-soluble iodine compound (sodium iodide) for visualizing the urinary tract was first described by Osborne in 1923. However, sodium iodide was accompanied by a high incidence of side effects and the image quality was not good. As newer, improved contrast agents were introduced, a number of investigators reported on the incidence of death and side effects incurred by their use. In 1975, the first large-scale, multicenter, prospective study on the incidence of fatal and nonfatal reactions was reported by Shehadi. In this series, the overall incidence of adverse reactions was 5.65%, of which 3.77% were mild, 1.77% were moderate, 0.02% were severe, and 0.0007% were fatal. Shehadi also noted that a history of allergy doubled the risk of adverse reaction and a history of a previous adverse reaction to contrast material trebled the risk; also, the risk of a reaction to an intraarterial injection was half that of the risk associated with an intravenous injection. With the introduction of low osmolar nonionic agents, other large-scale studies were performed because these agents appeared to cause significantly fewer adverse reactions. However, they were from 10 to 15 times more expensive than their predecessors. In 1987, Lasser reported on the increased safety of ionic agents when patients were pretreated with steroids. Palmer in Australia and Katayama in Japan collected 120,000 and 335,000 patients, respectively, and compared the incidence of adverse reactions of the ionic versus the nonionic agents. Wolf recently reported a study that included a direct comparison of ionic agents with pretreatment with steroids versus nonionic agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrast Media↗
PubMed1990

Acute cervical spine trauma: correlation of MR imaging findings with degree of neurologic deficit.

A retrospective analysis of magnetic resonance (MR) imaging studies of 78 patients with acute cervical spinal cord injuries was undertaken to determine which observations related directly to the neurologic injury. All MR imaging studies were performed on a 1.5-T unit and assessed with respect to 14 parameters related to the bony spine, ligaments, prevertebral soft tissues, intervertebral disks, and spinal cord. Forty-eight patients also underwent non-contrast material-enhanced thin-section computed tomography (CT) of the cervical spine. MR imaging was the definitive modality in the assessment of soft-tissue injury, especially in the evaluation of the spinal cord and intervertebral disks. All patients with a neurologic deficit had abnormal spinal cords at MR imaging. Intramedullary hemorrhage was predictive of a complete lesion. The degree of associated bone and soft-tissue injury had no bearing on the extent of spinal cord injury or neurologic deficit. Patients with residual cord compression following reduction demonstrated greater neurologic compromise than those without compression.

Acute Disease↗
PubMed1975

An approach to the performance of contrast studies in contrast material-reactive persons.

A method of carrying out contrast studies was considered for use in 124 persons with past histories of adverse reactions to contrast media. High-dosage steroid treatment was given before and during the contrast study to 37 patients with previous rash responses and 9 with prior anaphylactoid reactions; only 3 and 1 patients, respectively, of these groups had mild adverse reactions. Patients with past reactions deemed "vasomotor" underwent contrast study without preparative drug therapy without significant adverse effects. Although uncontrolled, this study suggests a possible protective role of steroids in patients with certain previous reactions to contrast media. We do not wish to imply that this is the only approach that can be used in the kind of patients reported here.

Adrenal Cortex Hormones↗