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Biomedical subjects

R Chisin

Publications and source records attributed to R Chisin.

At least 91 records · Page 5Linked to original sources
PubMed1986

Nuclear magnetic resonance proton imaging of bone pathology.

Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.

Adolescent↗
PubMed1986

Medial tibial pain. A prospective study of its cause among military recruits.

In a prospective study of 295 infantry recruits during 14 weeks of basic training, 41% had medial tibial pain. Routine scintigraphic evaluation in cases of medial tibial bone pain showed that 63% had abnormalities. A stress fracture was found in 46%. Only two patients had periostitis. None had ischemic medial compartment syndrome. Physical examination could not differentiate between cases with medial tibial bone pain secondary to stress fractures and those with scintigraphically normal tibias. When both pain and swelling were localized in the middle one-third of the tibia, the lesion most likely proved to be a stress fracture.

Fractures, Bone↗
PubMed1985

A prospective study of the effect of a shock-absorbing orthotic device on the incidence of stress fractures in military recruits.

In a prospective study of stress fractures the hypothesis that a shock-absorbing orthotic device worn within military boots could lessen the incidence of stress fractures was tested. The incidence of metatarsal, tibial, and femoral stress fractures was lower in the orthotic group, but only the latter difference was statistically significant. The time of onset and the location of stress fractures between orthotic and nonorthotic users did not differ. These findings suggest that the incidence of femoral stress fractures, which are the most dangerous type of stress fracture because of their high risk of developing into displaced fractures, can be reduced by an orthotic device.

Fractures, Bone↗
PubMed1985

Stress fractures in military recruits. A prospective study showing an unusually high incidence.

In a prospective study of 295 male Israeli military recruits a 31% incidence of stress fractures was found. Eighty per cent of the fractures were in the tibial or femoral shaft, while only 8% occurred in the tarsus and metatarsus. Sixty-nine per cent of the femoral stress fractures were asymptomatic, but only 8% of those in the tibia. Even asymptomatic stress fractures do, however, need to be treated. Possible explanations for the unusually high incidence of stress fractures in this study are discussed.

Adolescent↗
PubMed1985

Nuclear magnetic resonance imaging of liver hemangiomas.

Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with 99mTc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by 99mTc-labeled RBC scintigraphy.

Adolescent↗
PubMed1985

An unusual case of rheumatic pneumonia.

A 14-year-old boy developed severe respiratory failure during the course of acute rheumatic fever. The results of all microbiological studies were normal. Rheumatic carditis or left ventricular failure was excluded by routine examinations, catheterization of the right side of the heart, and multiple-gated radionuclide ventriculography. The patient recovered completely after a course of high-dose prednisone. To our knowledge, this is the first well-documented case of rheumatic pneumonia in which the lung disease could be attributed to the rheumatic disease and not to a pathologic heart condition.

Acute Disease↗
PubMed1983

Patterns of auditory nerve and brainstem-evoked responses (ABR) in different types of peripheral hearing loss.

Auditory brainstem response (ABR) recordings were made in different types of peripheral hearing loss (sensorineural, conductive, and mixed). Scatter diagrams were constructed by plotting different expressions of the hearing loss (audiometric and electrophysiologic) against the obtained wave latencies and for these two sets of variables, correlation coefficients and the parameters of the regression equation were calculated. Consideration is given to the possibility of diagnosing the type of peripheral hearing loss by correlating wave latencies and the electrophysiologic (ABR) threshold.

Adolescent↗
PubMed1982

Auditory nerve-brain stem potentials in man and cat under hypoxic and hypercapnic conditions.

In order to study the effects of hypoxic and hypercapnic respiratory gas mixtures on brain activity, the auditory nerve brain stem evoked potentials (ABP) were recorded in 6 human volunteers and in 12 cats while they were breathing various gas mixtures. In humans, no effect of gas mixtures containing 9-13% O2 or 7.5-10% CO2 was observed on the wave form, latency and amplitude of the ABP. The cats were exposed to up to 25% CO2 and down to 5.5% O2 or to combined hypoxic and hypercapnic gas mixtures for up to 45 min while recording ABP and monitoring CO2 and O2 in the respired gases, arterial blood gas levels, pH, arterial blood pressure, body temperature and EEG. The extremes of pH were 6.68 and 7.46. The EEG was depressed or became isoelectric during hypercapnia. In general, the wave form, amplitude and latencies of the ABP waves were not much affected by these conditions. Loss of ABP was observed only when the animal was ventilated with about 5% O2 and this was secondary to and following cardiac failure and depressed arterial blood pressure, presumably leading to brain ischaemia. Thus, even though the cortex (EEG) is depressed, the brain stem seems to be resistant to these alterations in the blood gases in spite of the relatively higher rates of metabolism reported for the brain stem auditory structures.

Adult↗
PubMed1978

Auditory nerve and brain stem responses. Comparison in awake and unconscious subjects.

The recording of auditory nerve and brain stem responses to click stimuli is being used for the diagnosis of several conditions such as suspected hearing loss and suspected neurological disorders. The responses obtained in the patient group (often infants and children) are compared with those obtained in normal subjects of similar age who, for ethical reasons, are not sedated. In this study, recordings were made in normal subjects while they were awake and when they were unconscious in drug-induced sleep (being prepared for dental surgery). No significant difference could be observed between the recordings obtained in the awake state and when unconscious in the same subjects. Therefore, one is justified in using recordings made in awake subjects as controls for recordings made in other unconscious patients.

Brain Stem↗
PubMed1977

Early repair of blast ruptures of the tympanic membrane.

A method and results of early repair of blast rupture of the tympanic membrane in 24 selected cases, where flaps and/or free edges of the torn eardrum could be detected by examination with the operating microscope, are presented. By reversion of the flaps and approximation of the edges, the perforation was closed or significantly diminished. This ensured the healing of the tympanic membrane in all cases within days instead of months. No complications were noted during a subsequent two to three-years' follow-up. The improved hearing was stable.

Adolescent↗
PubMedDate not supplied

MR imaging of a lymphangioma involving the masseter muscle.

Lymphangiomas and cystic hygromas are tumors of lymphatic origin that are relatively common in the head and neck area. However, based on our literature review of this subject, the masseter muscle has never been implicated as a primary tumor site. It is our purpose to report such a case and to emphasize the value of magnetic resonance imaging for diagnosing a mass located in the masseteric region.

Adult↗