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Biomedical subjects

R Petsch

Publications and source records attributed to R Petsch.

13 recordsLinked to original sources
PubMed1991

Brain dysfunction during motor activation and corpus callosum alterations in schizophrenia measured by cerebral blood flow and magnetic resonance imaging.

Sixteen unmedicated (14 never-medicated, 2 with washout periods of 1-2 weeks) schizophrenic patients displaying positive symptoms (e.g., formal thought disorder, hallucinations, delusions) without negative symptoms (e.g., flattening of affect, loss of energy, anhedonia--type I patients), 15 unmedicated (with washout periods from 1 week to 2 years) patients with marked negative symptomatology [type II patients; criterion score below 15/above 35 on the Munich version of the Scale of Assessment of Negative Symptoms (SANS), respectively], and 31 matched normal controls were investigated using regional cerebral blood flow [rCBF; dynamic single-photon emission computerized tomography (SPECT) with Xenon-133 as tracer] and magnetic resonance imaging (MRI; spin-echo technique, T1 weighted, midsagittal cuts). rCBF measurements were performed during both resting conditions and simple motor activation. Separately, on the same day, we performed a planimetric evaluation of the callosal-brain ratio in all subjects using MRI. In accordance with previous results on a smaller sample, we found signs of diffuse bilateral rCBF hyperactivation in type I patients, as compared with signs of nonreactivity in type II schizophrenics. Both activation patterns were different from a strictly contralateral sensorimotor rCBF activation seen in normal persons (only 8 studied with SPECT). The planimetry of relative callosal area did not reveal differences compared to normal persons, when type I/II patients were taken together. However, the threefold increased variance as compared with that found in normal persons suggested biological heterogeneity in patients. We found an increase of relative callosal size in type I as compared with type II patients. In the light of some recent findings linking lack of laterality of several brain functions to increased callosal size, we propose lack of laterality/diffuse hyperactivation and increased callosal size to be connected with positive symptomatology/good prognosis schizophrenia, and vice versa.

Activities of Daily Living↗
PubMed1991

[High resolution tridimensional study of the blood vessels of the neck and the intracranial circulation with magnetic resonance angiography].

Magnetic Resonance Angiography (MRA) is a modern vascular imaging technique which allows the noninvasive and direct imaging of vessels. The authors aimed at evaluating the diagnostic accuracy of MRA in the study of pathologic conditions in the neck and intracranial vessels; spatial resolution of the technique was also investigated. Twenty-four healthy volunteers and 82 patients suffering from various diseases of the head and neck vessels were included in the study. First of all, MRA capabilities were investigated in visualizing normal vessels of both neck and intracranial circle. The diagnostic accuracy of the method was then evaluated in the study of vascular diseases, and the results compared with conventional/digital angiographic findings. The comparison demonstrated how stenoses and atherosclerotic plaques tend to be overestimated by MRA because of technical artifacts inherent to the technique itself, whereas vascular ulcerations and aneurysms are frequently underestimated. However, this data was steady and therefore evaluable--the exact knowledge of the artifacts making diagnosis reliable. The diagnostic and technical problems relative to the various vascular diseases are discussed. Finally, several hypotheses of diagnostic iter are suggested.

Angiography, Digital Subtraction↗
PubMed1988

[Comparative studies of cerebral blood flow measurements and measurements of the size of the corpus callosum in patients with schizophrenia].

In this study healthy subjects and schizophrenic patients of the so-called Type I and Type II subgroups were examined in each case with a morphological method to determine the size of the corpus callosum and with a method to measure a physiological functional parameter, namely, the regional cerebral blood flow (rCBF). MR and dynamic single photon emission CT were used (in our case as differential method). The study reveals for the first time classified into subgroups of the disease, scientifically measured differences both in the size of the corpus callosum and in the distribution pattern of the blood flow. Whereas the patients of type I had an enlarged corpus callosum and increased blood flow during the task with which they were confronted, these organs were mainly smaller in size with type II patients without an increase in the global blood flow during the relevant task. The statistical data--averaged over patient groups--show these differences clearly, but due to biological scatter it has so far not been possible to arrive at a diagnosis in individual cases.

Adult↗
PubMed1987

[Magnetic resonance tomography of the postoperative lumbar spine. A comparison of the MR versus CT images in recurrent intervertebral disk prolapse].

In the present study, 40 patients who had undergone disc surgery were examined by high resolution CT and MR for possible recurrence of the disc prolapse and the results are compared. It appears that high resolution spinal MR, using its various tissue parameters provides no new insights into possible recurrence of a disc prolapse. As is the case with CT, the investigator must also evaluate other morphological and clinical factors. In spite of this, MR can be useful in the investigation of abnormal spines.

Diagnostic Errors↗
PubMed1986

Disk processes in MR.

Disk processes can be differentiated in MR with the introduction of high resolution coils and the use of a multi slice technique with a minimal slice thickness of 5 mm. By using a sensitive double echo sequence we found that in the 80 patients examined the size and extent of the posterior herniation could be well demonstrated. Sagittal slices show the relationship of the herniation to the spinal cord. The pathomechanical parts of a disk process such as ruptured or preserved anulus fibrosus, perforated or intact posterior longitudinal ligament can be differentiated. For lateral lying processes in connection with the foramen intervertebral and the spinal roots an axial slice parallel to the intervertebral space is recommended. All CT findings especially in the cervical spine region were shown and further qualified.

Cervical Vertebrae↗
PubMed1985

[Nuclear magnetic resonance tomography of the spine].

The present paper deals with the results of 48 MR examinations of known spinal abnormalities. The use of a method strictly related to the individual problem helps to reduce the duration of the examination. Sagittal cuts are particularly useful for demonstrating much of the spinal canal. The spin-echo method is used for all examinations. Demonstration of the cord was performed by using short repetition and echo times (TR, TE). For showing the outer margin of the spinal canal, longer TR and TE should be selected. Surface coils are important for demonstrating spinal disease, since the larger images can be performed without increasing the duration of the examination.

Humans↗
PubMed1985

[MR imaging of the cervical spine using special coils].

The signal/noise ratio of MR images can be improved for organs near the surface by means of special coils. It is shown for neck imaging that a close-fitting saddle-shaped coil is more suitable for application between C 2 and Th 1, than a saddle coil for the entire head or a disc-shaped coil. Such a close-fitting saddle-shaped coil is an essential prerequisite for effective neuroradiological diagnoses of the spinal cord with nerve roots, of the spinal column, and of the vessels of the neck.

Cervical Vertebrae↗