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Biomedical subjects

R Chisin

Publications and source records attributed to R Chisin.

At least 55 records · Page 3Linked to original sources

Brain SPECT imaging of neuropsychiatric disorders.

Brain imaging has become an integral part of the evaluation of neurological and psychiatric disorders. Functional imaging techniques, SPECT and PET, together with structural modalities, CT and MRI, are widely employed. Functional imaging studies are routinely used in the diagnostic workup of patients with well-characterized neurological disorders, such as epilepsy and brain tumors, and have a growing role in research on psychiatric disorders without known mechanisms such as depression and schizophrenia. Furthermore, many well-defined neurological disorders manifest prominent psychiatric symptomatology which may pose difficulties in differential diagnosis. This review addresses the current knowledge of SPECT findings in patients who present with psychiatric phenomena, associated with disorders at the interface of neurology and psychiatry.

Alzheimer Disease↗

Use of 201Thallium brain SPECT, image registration, and semi-quantitative analysis in the follow-up of brain tumors.

OBJECTIVE: To assess the use of 201Thallium SPECT and of Thallium (Tl) uptake indices in the detection and follow-up of cerebral tumors. MATERIAL AND METHODS: Two-hundred eighty 201Tl, 135 99mTc-HMPAO scintigraphies and 280 MRI studies were acquired in 135 patients with cerebral tumors. Three types of Tl uptake indices were calculated by establishing the ratio of the lesion activity to an homologous ROI (I1), the contralateral hemisphere (I2), and the contralateral scalp (I3). Intermodal coregistration between Tl-SPECT and MRI when used, was performed using Pietrzyk visual interactive method. RESULTS: Tl uptake indices showed mean values of 2.0 +/- 0.5 (I1); 1.77 +/- 0.57 (I2) and 1.11 +/- 0.40 (I3) in positive scans, and of 1.05 +/- 0.22 (I1), 0.88 +/- 0.22 (I2) and 0.50 +/- 0.15 (I3) in negative scans, respectively. A linear combination of the two less correlated indices lead to a more powerful discrimination between positive and negative studies. Longitudinal follow-up studies in the same patients showed good concordance between the index values and the course of the disease. CONCLUSION: The use of Tl uptake indices improves the accuracy of Tl-SPECT in the follow-up of brain tumors.

Adolescent↗

Major salivary gland dysfunction in human acute and chronic graft-versus-host disease (GVHD).

Salivary gland dysfunction is frequently observed in patients suffering from acute (a) and chronic (c) GVHD. We studied the influence of GVHD on the function of major salivary glands in 20 patients with GVHD (cGVHD, 15; aGVHD, 5). A subjective evaluation of salivary function was performed, in which the score ranged from 0-4 where a higher score indicated more oral dryness. Patients with aGVHD scored 4.0 while patients with cGVHD scored 2.1 (P < 0.01). In addition to this subjective evaluation, patient's salivary flow rates were measured and a reduction of 90% and 60% in aGVHD and cGVHD patients respectively, was observed as compared to controls (P < 0.01; P < 0.05). No hyposalivation was observed in patients who underwent bone marrow transplantation but did not develop GVHD as compared to normal individuals. A direct correlation was observed between the degree of hyposalivation and the severity of the GVHD. Hyposalivation was also documented by scintigraphy of the major salivary glands in the GVHD patients. Furthermore, hyposalivation was associated with extensive mucosal atrophy, erythema, tongue surface depapillation, lichenoid lesions of the buccal and labial mucosa as well as lupus-like lesions. Routine assessment of these glands in patients with GVHD could play a role in monitoring response to therapy.

Acute Disease↗

Increased cerebral blood flow in depressed patients responding to electroconvulsive therapy.

UNLABELLED: Considerable data support the existence of impaired regional cerebral blood flow (rCBF) in major depression. We compare rCBF in depressed patients before and after electroconvulsive therapy (ECT) to define whether the impairment is a "state"-related property or a trait phenomenon. METHODS: Twenty patients with a major depressive disorder were studied by 99mTc-HMPAO brain SPECT, 2-4 days before and 5-8 days after a course of ECT. Three transaxial brain slices delineating anatomically defined regions of interest at approximately 4, 6 and 7 cm above the orbitomeatal line were used, with the average number of counts for each region of interest normalized to the area of maximal cerebellar uptake. RESULTS: Technetium-99m-HMPAO uptake significantly increased in patients who responded to ECT but remained unchanged in patients who did not respond to the treatment (response defined as a reduction of at least 60% on the Hamilton Depression Rating Scale). An inverse correlation was observed between severity of depression and HMPAO uptake, and clinical improvement was positively correlated with the increase in tracer uptake. CONCLUSIONS: These findings imply that reduced rCBF in depression, as reflected in brain 99mTc-HMPAO uptake, is a "state"-related property and is reversible by successful treatment. Technetium-99m-HMPAO uptake may serve as an objective state marker for depression, an an indicator of the severity of depression and as an objective means of evaluating response to treatment.

Brain↗

Bone scintigraphy in the assessment of the hallucal sesamoids.

Bone scintigraphy is frequently used to evaluate suspected hallucal sesamoid pathology. Increased scintigraphic activity of the hallucal sesamoid is assumed to corroborate clinical suspicion of pathology, but the incidence of such increased uptake has not been studied in an asymptomatic population. Using a 0 to 2 bone scintigraphic rating system, 25 of 86 (29%) asymptomatic infantry recruits and 7 of 27 (26%) asymptomatic sedentary adults were found to have grade 1 or grade 2 activity. When using scintigraphy to evaluate hallucal sesamoid pathology, caution should be used in interpreting the meaning of increased scintigraphic activity.

Adolescent↗

The use of iridium-191m for pulmonary blood flow imaging.

A preliminary evaluation of the potential utilization of osmium-191/iridium-191m for pulmonary blood flow imaging was performed. This evaluation was part of a more general study concerning the use of 191mIr for first-pass radionuclide angiocardiography (FPRNA). In eight selected patients with suspected pulmonary disease, we generated, from the data collected during FPRNA, an image representing blood flow distribution to the lungs. A software program was developed in order to differentiate the lungs from the heart, to define the wash-in lung phase and finally to construct an image representing pulmonary blood flow distribution. We compared that image with a standard lung perfusion image using technetium-99m macroaggregated albumin (MAA) and plain chest X-ray and computerized tomography (CT). The obtained 191mIr perfusion images showed a spatial activity distribution similar to that seen on 99mTc-MAA lung perfusion scans, and in most cases the same perfusion defects. Disease revealed by plain chest X-ray and CT was nicely correlated with perfusion defects seen on the 191mIr images. The combined information of lung perfusion and dynamic cardiac parameters obtained by FPRNA (right and left ventricular ejection fractions) added another relevant dimension to the clinical picture of patients with pulmonary embolism, chronic obstructive lung disease, lung tumour or suspected congestive heart failure. We conclude that 191mIr may become a practical tool for achieving the conceptually promising approach of combined lung-heart real-time imaging.

Humans↗

A measurement of pulmonary blood volume increase during systole in humans.

Pulmonary blood volume increase during systole was measured in patients by analysing chest images obtained during ECG gated radionuclide angiography examination. The difference in the total radiation counts between systole and diastole in regions of interest, which included the lungs and the left ventricle, was measured and the relative pulmonary systolic blood volume increase (SBVI)-the ratio between the pulmonary SBVI and the cardiac stroke volume-was calculated. The relative pulmonary SBVI, which is a measure for the compliance of the pulmonary blood vessels, was found to be 0.26-0.85, and the average value was 0.57 +/- 0.15. The relative pulmonary SBVI was inversely correlated with the patient age (r = 0.27, p < 0.05) and with the left ventricular ejection fraction and stroke volume (r = 0.36, p < 0.01) due to decreased arterial compliance for older patients and for increased pulmonary blood volume respectively. The correlation coefficients were not high, indicating that the compliance of the patients is determined mainly by other individual factors. Radionuclide plethysmography enables qualitative assessment of pulmonary arterial compliance.

Aging↗

Breast artifact in planar cardiac imaging: a comparison of 201T1 to sestamibi-99mTc.

Breast artifact occurrence during 201T1 myocardial image interpretation is a significant problem. We serially evaluated 3 female patients utilizing exercise treadmill perfusion studies in order to assess the potential role of 99mTc-Sestamibi (MIBI) imaging in the setting of documented 201T1 breast artifact. Both visual and quantitative analyses revealed no superiority of 99mTc-MIBI over 201T1 imaging in reference to avoidance of breast artifact. The variation in artifactual cardiac imaging defects in the 3 patients most probably reflected variations in breast positioning. Finally, the ability to assess ventricular wall motion via gated 99mTc-MIBI imaging may help to confirm an artifactual versus an actual myocardial perfusion abnormality.

Aged↗

Imaging of lymphoma manifestations in the extracranial head and neck region.

CT and MRI are the most efficient imaging techniques for diagnosing lymphomas while Gallium-67 scintigraphy is used to assess treatment results. In this review, the imaging aspects of lymphoma are addressed according to anatomical subregions, from the orbit to the trachea, Waldeyer's ring being the most common site, in the head and neck. Lymphomas of this region are not easily distinguished from the more common squamous cell carcinomas; however, multiple extranodal sites, the presence of many non-necrotic lymph nodes and a large nasopharyngeal mass without significant bone destruction should alert one to the possibility of lymphoma.

Gallium Radioisotopes↗

Value of dobutamine/nitrate radionuclide angiography in predicting revascularization effects on ventricular function.

OBJECTIVE: Dobutamine and Nitrate Radionuclide Angiography (RNA) may help to distinguish viable from nonviable myocardium and to predict revascularization effects on LV function. SETTING: Ambulatory. EXPERIMENTAL DESIGN: Prospective. PATIENTS AND METHODS: We studied 12 patients (11 male, 1 female; mean age 56 +/- 10 years) with three-vessel disease, severe LV dysfunction, and prior MI for a mean follow-up time of 10 +/- 3.4 months. Thallium-201 scintigraphy favored potential viability in all patients: inducible ischemia with satisfactory perfusion in more than one coronary arterial territory. Global and regional LVEF's were calculated from preoperative RNA (baseline rest study and with continuous dobutamine infusion with gradual rate increase plus oral nitrates) and postoperative RNA at 1 and 6 months. RESULTS: There was no operative mortality, but two late deaths occurred. Symptomatically, most patients showed improvement. Global LVEF increased during dobutamine and nitrates preoperatively (p < 0.01), but not at 1 and 6 months postoperatively (without pharmacological intervention). Mean LVED volume was not significantly changed postoperatively. Regional EF improvement was found in 4 out of 9 LV wall segments under dobutamine and nitrates, and this increase persisted postoperatively at 1 and 6 months. CONCLUSIONS: Mild but significant increase in global LVEF during dobutamine and nitrates administration is not predictive of postoperative LVEF improvement. However, regional EF improvement appears to be predictive of post-revascularization LV functional improvement.

Administration, Sublingual↗

Transient neurological events during dipyridamole stress test: an arterial steal phenomenon?

Dipyridamole-associated adverse neurological side effects have not been extensively described. We present two cases of dipyridamole-associated transient motor neurological events with no evidence of residual neurological deficits detected clinically or by head CT. The patients showed no evidence of significant extracranial (internal carotid) artery disease. We propose the presence of a regional cerebral perfusion disturbance due to an intracranial vascular steal phenomenon as the mechanism for the above side effects of dipyridamole.

Aged↗

Salivary and lacrimal gland involvement in a patient who had undergone a thyroidectomy and was treated with radioiodine for thyroid cancer.

A patient with bilateral, insidiously developing enlargement of the parotid glands that started 1 year after a total thyroidectomy and ablative radioiodine therapy (200 mCi I131) for papillary carcinoma is presented. The patient displayed prolonged periods of hypothyroidism accompanied by hypercholesterolinemia, notwithstanding hormone replacement therapy. Three years after surgery, parotid and lacrimal gland functions were reduced and fatty degeneration of the parotid parenchyma was demonstrated histologically. The submandibular and sublingual glands were preserved. It is suggested that the hormonal and metabolic derangements are responsible for the glandular dysfunction, rather than a direct effect of iodine on the glands.

Adult↗

Registration and display of multimodal images: applications in the extracranial head and neck region.

Image registration is a correlation procedure that allows the matching of images obtained by different imaging modalities, both structural and functional. Once registered, they can be combined in a single "fused" image. This technique can be used to improve the interpretation and the quantification of relatively low resolution images obtained in nuclear medicine or to achieve a better diagnosis and treatment planning when high resolution anatomical images are registered. Matching images obtained by different imaging modalities is a major challenge and the various registration techniques are briefly described. The extracranial head and neck region is a challenging field for image registration. A preliminary retrospective experience is presented emphasizing the technique feasibility in a routine clinical context. 2-D and 3-D approaches were used. The requirements for transferring registration technology from the image processing laboratory to clinical practice are discussed, and the contribution of this method to medical interdisciplinary communication is emphasized.

Aged↗

The clinical assessment of femoral stress fractures: a comparison of two methods.

In a prospective study among 667 recruits, the incidence of asymptomatic femoral stress fractures was compared using a new expanded stress fracture clinical examination (SFCA) versus an older stress fracture examination. There was a statistically significant difference (p = 0.0001) between the percentage of femoral stress fractures that were asymptomatic in the group evaluated by SFCA (26%) and those evaluated by the older stress fracture examination (80%). By using the SFCA, many of the femoral stress fractures previously classified as asymptomatic are in fact recognized as symptomatic.

Femoral Fractures↗