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R Chisin

Publications and source records attributed to R Chisin.

At least 37 records · Page 2Linked to original sources
PubMed2000

Contribution of whole body F-18-FDG-PET and lymphoscintigraphy to the assessment of regional and distant metastases in cutaneous malignant melanoma. A pilot study.

AIM: This pilot study describes use of whole body PET (WB PET) for staging of melanoma. WB PET in conjunction with lymphoscintigraphy (LS) for evaluating status of the sentinel lymph node (SLN) in primary melanoma was investigated with comparison to histopathological results. WB PET was also used both for primary and metastatic melanoma for screening for distant metastases, restaging and follow-up. METHODS: Group I: 17 patients with primary cutaneous melanoma underwent LS, WB PET and SLN dissection. WB PET findings were compared with biopsy results at the SLN site and were used for screening for distant metastases. Group II: 17 patients with a history of melanoma underwent WB PET for follow-up and/or restaging. Results were confirmed or refuted by other radiological modalities or by biopsy or clinical follow-up. RESULTS: Group I: out of 20 SLNs identified by LS in the 17 patients, 18 were negative on WB PET and 2 were positive. 19/20 WB PET findings were confirmed either by histopathology or by clinical follow-up (20 mo). Accuracy was 94% for the assessment of the status of the SLN. Group II: WB PET findings altered staging and treatment in 12/17 patients and confirmed the validity of treatment in 3/17 patients. Overall, in 15/17 patients (88%), WB PET had an impact on treatment strategy. CONCLUSION: Further studies are required to demonstrate if WB PET can become a reliable non-invasive alternative to surgery in the characterization of the SLN. WB PET is important as a baseline in primary localized melanoma and decisively impacts patient management in metastatic melanoma.

Adult↗
PubMed1999

Dermoid cyst of the eustachian tube.

We report a case of dermoid cyst of the Eustachian tube in a 2 1/2 -year-old-girl with CT and MRI imaging. This is the 12th described case of such a pathology. Most of the reviewed previous 11 cases affected females on the left side. The surgical approach and the contribution of CT and MRI are discussed.

Child, Preschool↗
PubMed1999

Clinical doses of fluoxetine and cerebral blood flow in healthy volunteers.

RATIONALE: Of the specific serotonin reuptake inhibitors (SSRIs), fluoxetine is perhaps the most widely used. Anecdotal reports, mostly in the non-medical press, have suggested that it may positively affect psychological functioning and enhance quality of life in the absence of overt psychiatric disorder. Such wide-spread use in not supported by scientific data. OBJECTIVE: This prospective single blind study examined the effects of long term administration of clinical doses of fluoxetine on cerebral blood flow (CBF) in healthy volunteers. METHODS: Fifteen healthy subjects were examined by Tc99m HMPAO SPECT after 2 weeks of placebo administration and then after 6 weeks of fluoxetine, administered at 20 mg per day. Blood for fluoxetine and norfluoxetine plasma levels was drawn to ensure compliance. Tc99m HMPAO uptake was analyzed by the region of interest approach, normalized to the cerebellum, and by statistical parametric mapping (SPM). RESULTS: No statistically significant differences between the two conditions were detected by both techniques. Correlation analysis between fluoxetine and norfluoxetine plasma levels and rCBF yielded no statistically significant values. CONCLUSION: Our findings suggest a differential effect of fluoxetine on CBF under the following conditions: (i) mental health versus psychiatric illness; (ii) acute versus long term administration. Our findings further emphasize the importance of longitudinal studies in elucidating the physiology of the normal brain as well as the pathophysiology of psychiatric disorders.

Adult↗
PubMed1999

Long-term outcome of patients with very long stents for treatment of diffuse coronary disease.

OBJECTIVES: The study sought to determine the 6-month clinical outcome of patients who underwent implantation of very long coronary stents to treat diffuse disease and/or long dissections and to compare the findings with those reported in the literature for patients who underwent implantation of multiple short coronary stents. BACKGROUND: New designs of flexible stents enable the implantation of long stents rather than multiple short, older design stents. The initial experience is very promising but the long-term outcome has not been described yet. METHODS: Fifty-seven consecutive patients in whom 67 long stents (>/=30 mm) were successfully deployed were included in this study. Six-month clinical and angiographic follow-up was prospectively collected. Patients with recurrent angina underwent coronary angiography without further testing. Patients who remained asymptomatic at the 6-month follow-up visit underwent positron emission tomographic imaging, and those with results suggestive of ischemia underwent coronary angiography. A combined study end point was defined as death, myocardial infarction, and the need for target vessel revascularization. RESULTS: Only 1 patient (2%) reached a study end point at hospital discharge. An additional 20 patients (total 21 patients [37%]) reached an end point by 6 months. The outcome was not influenced by the clinical presentation (stable or unstable angina) or by the indication for stenting (elective or emergency). Predictors for adverse outcome were multiple stents per narrowing (63% vs 29%, P <. 04), and stents smaller than 3.5 mm (49% vs 22%). Narrowing and stent length were not predictive of a study end point in narrowings that were successfully treated by a single long stent. CONCLUSIONS: Elective stenting provides an effective solution for patients with diffuse coronary disease provided that a single long stent (usually <40 mm) can cover the full length of the narrowing. The results are better when vessels larger than 3 mm are treated. Compared with multiple short stents, implantation of a single long stent is probably at least as effective, and the procedure is quicker and cheaper and thus should be the preferred approach.

Aged↗
PubMed1999

Somatostatin receptor scintigraphy for early detection of regional and distant metastases of medullary carcinoma of the thyroid.

Three patients are described who had regional and distant metastases of medullary thyroid cancer detected by somatostatin receptor scintigraphy but not by CT; two had minimal disease that was amenable to surgery. The first patient had been followed for 2 years before having a repeated scan and positive CT, with subsequent surgical removal of metastatic paratracheal nodes. The plasma calcitonin level, however, did not approach normal values after surgery, and a third scan showed persistence of focal uptake in the left paratracheal area of the lower neck, whereas CT was negative. At repeated exploration, a tumor mass of medullary carcinoma, embedded in lymphatic tissue, was removed. Nine months after the last surgical procedure, calcitonin and carcinoembryonic antigen levels were normal. The second patient underwent microdissection of the mediastinum and removal of two metastatic nodes that were demonstrable only by the scintigraphic technique. The plasma calcitonin level subsequently became normal. The third patient, with multiple endocrine neoplasia IIB and associated pheochromocytoma, had bony metastatic involvement of the left shoulder, demonstrable initially on somatostatin receptor scintigraphy and subsequently with radioiodinated metaiodobenzylguanidine but not on CT.

3-Iodobenzylguanidine↗
PubMed1998

Age-related changes in brain perfusion of normal subjects detected by 99mTc-HMPAO SPECT.

Previous functional imaging data generally show impairment in global cerebral blood flow (CBF) with age. Conflicting data, however, concerning age-related changes in regional CBF (rCBF) have been reported. We examined the relative rCBF in a sample of healthy subjects of various ages, to define and localize any age-related CBF reduction. Twenty-seven healthy subjects (17 male, 10 female; mean age 49 +/- 15, range 26-71, median 47 years) were studied by 99mTc-HMPAO brain SPECT. The younger age group consisted of subjects below, the older group above 47 years of age, respectively. Analysis was performed by applying three preformed templates, each containing delineated regions of interest (ROIs), to three transaxial brain slices at approximately 4, 6, and 7 cm above the orbitomeatal line (OML). The average number of counts for each ROI was normalized to mean uptake of the cerebellum and of the whole brain slice. Globally, 99mTc-HMPAO uptake ratio normalized to cerebellum was significantly decreased in older subjects, affecting both hemispheres. A slight left-to-right asymmetry was observed in HMPAO uptake of the whole study group. It did not, however, change with age. Regionally, both cortical and subcortical structures of older subjects were involved: uptake ratio to cerebellum was significantly lower (after correction for multiple testing) in the left basal ganglia and in the left superior temporal, right frontal and bilateral occipital cortices at 4 cm above the OML. At 6 cm above the OML, reduced uptake ratios were identified in the left frontal and bilateral parietal areas. At 7 cm, reduced uptake was detected in the right frontal and left occipital cortices. Most of these differences were reduced when uptake was normalized to whole slice, whereas an increase in uptake ratios was observed in the cingulate cortex of the elderly. An inverse correlation between age and HMPAO uptake ratios normalized to cerebellum was observed in a number of brain regions. These findings suggest that advancing age has a differential effect on cerebral perfusion reflected in brain 99mTc-HMPAO uptake.

Aging↗
PubMed1998

Somatostatin-receptor scintigraphy in the management of gastroenteropancreatic tumors.

OBJECTIVE: This study evaluates the diagnostic and therapeutic implications of somatostatin-receptor scintigraphy in the management of patients with proven or high clinical suspicion of gastroenteropancreatic endocrine tumors. METHODS: Forty-one patients were studied by planar and tomographic imaging at 4 h and 24 h after 111In-pentetreotide injection. Scintigraphic findings were compared with computed tomography, and in several patients also with ultrasound, angiography, biopsy, and/or surgery, when performed. RESULTS: Among 23 patients with carcinoid tumor, three of nine primary tumors were initially identified by scintigraphy. Unsuspected mesenteric metastases found on scintigraphy in three patients led to octreotide treatment. Scintigraphic detection of multiple metastases in a patient with thyroid metastasis of bronchial carcinoid spared her an unnecessary total thyroidectomy. Among 18 patients with 19 islet-cell tumors, scintigraphy detected three of five insulinomas, whereas computed tomography identified only one. Receptor positivity in an islet-cell tumor (vipoma?) with no metastases on the scan led to surgical removal of the primary tumor. Receptor-positive metastases of gastrinoma (two of three patients), glucagonoma (two of three patients), and parathyroid hormone-related peptide-producing tumor (one patient) led to octreotide treatment. Nonvisualization of metastases of a glucovipoma led to chemotherapy. CONCLUSIONS: Somatostatin-receptor scintigraphy contributes to the management of patients with gastroenteropancreatic tumors in the following ways: 1) localization of a primary occult tumor, allowing surgical removal; 2) staging of the disease for optimal therapy-surgical excision or systemic treatment; and 3) identification of receptor status of the metastases for octreotide treatment or chemotherapy.

Adenoma, Islet Cell↗
PubMed1998

Heart rate variability as a marker of myocardial perfusion.

RR variability (HRV), an independent predictor of death following myocardial infarction, may also be related to other features of coronary artery disease. We evaluated its ability to differentiate among sedentary patients with chest pain >/=45 years of age demonstrating either normal or abnormal myocardial perfusion with rest and exercise thallium-210 tomographic imaging. The major HRV difference between 48 men and 50 women with normal perfusion was a significantly higher high frequency power in women. No significant differences in mean HRV values were found between the 57 men with abnormal perfusion scans and the 48 men with normal perfusion. In both men and women with normal perfusion scans, duration of exercise was significantly related to age. In men with abnormal scans, impaired myocardial perfusion alters the relationship between exercise duration and age, and a group of individuals with diminished HRV and low levels of physical fitness, regardless of age, can be identified. Despite these latter selective findings, we conclude that HRV is not a sensitive indicator to differentiate patients with normal and abnormal myocardial perfusion.

Age Factors↗
PubMed1998

Preoperative thallium scanning, selective coronary revascularization, and long-term survival after carotid endarterectomy.

BACKGROUND AND PURPOSE: Long-term survival in patients after carotid endarterectomy (CEA) is determined mainly by their concomitant cardiac disease. We tested to determine whether preoperative thallium scanning (PTS) and subsequent selective coronary revascularization (CR), by either percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG), improve long-term survival after CEA. METHODS: Two hundred twenty-six of 255 consecutive patients (88%) undergoing CEA from 1990 to 1996 had PTS. Those with significant reversible defects on PTS were referred for coronary angiography and possible CR. Patients who had undergone PTS were divided into the following 4 groups: group 1, normal or mild defects on PTS; group 2, moderate-severe fixed and/or reversible defects in patients who did not undergo CR; group 3, patients who had CR secondary to their PTS results; and group 4, patients who had CR in the past that was not related to the PTS. Perioperative data were prospectively recorded, and data on long-term survival and cardiac and neurological complications were collected. RESULTS: Seventy-seven patients (34%) had preoperative coronary angiography, and 42 (19%) had subsequent CR: preoperative PTCA or CABG in 24, combined CEA+CABG in 10, and post-CEA CABG in 8 patients. No deaths resulted from the coronary angiography, CR, or CEA. Six patients had perioperative nonfatal myocardial infarction and 8 had stroke. During the follow-up (40+/-23 months), 47 patients (18%) died, 31 (66%) from cardiac disease and 4 (8.5%) from stroke. Independent predictors of long-term overall mortality were diabetes mellitus, preoperative T-wave inversion on ECG, lower-extremity arterial disease, and history of neurological symptoms [exp(beta)=3. 5, 3.4, 2.5, and 2.4; P=0.0003, 0.0004, 0.01, and 0.04, respectively]. In addition, preoperative moderate-severe thallium defect without CR (group 2) independently predicted long-term cardiac mortality [exp(beta)=2.8; P=0.04]. Patients with preoperative CR (group 3) had long-term survival rate similar to that of group 1 and significantly better than that of group 2 (P=0. 02). CONCLUSIONS: PTS predicts long-term survival, and selective CR based on the thallium results improves the survival rate of patients undergoing CEA.

Aged↗
PubMed1997

Role of high-resolution pinhole tomography in the evaluation of thyroid abnormalities.

The present study was undertaken to evaluate the contribution of pinhole-single photon emission computed tomography (P-SPECT) to scintigraphy of the thyroid gland. Thirty-six patients, referred for thyroid scintigraphy because of palpatory or ultrasonographic findings, were studied after intravenous administration of technetium-99m pertechnetate (222 MBq) using a rectilinear scanner and a single-headed rotating gamma camera equipped with a pinhole collimator. P-SPECT study was acquired on a 128 x 128 matrix, in 30 projections over 180 degrees and an acquisition time of 40 seconds per step. After transaxial reconstruction, coronal slices were compared with planar views obtained by the scanner. The size of the thyroid gland obtained by P-SPECT matched the life-size image of a rectilinear scan, and it clearly delineated the shape and borders of two huge multinodular glands. Its major contribution was in its improved resolution. Pinhole-SPECT identified 21 foci not visualized on planar views, 19 cold lesions, and 2 "warm" nodules embedded in normal tissue of 13 patients. Furthermore, it clearly delineated 18 discrete ill-defined nodules of 13 patients, (single in 4 patients and multiple in 9 patients): 16 cold lesions, and 2 hot foci. When a distinct palpable nodule was present, whether cold (22 lesions) or hot (2 foci), SPECT was of no additional diagnostic value. However, when the palpable nodule was a toxic one, the contralateral suppressed lobe was visible on SPECT only. Two ultrasonographic findings, of 3- and 5-mm in diameter, were neither identified on planar views nor on P-SPECT. In conclusion, P-SPECT of the thyroid gland improves delineation of huge multinodular glands and detection of small nodules (within the resolution of the camera) that could otherwise have been overlooked on planar views of a thyroid scanner. It allows for definition of tracer uptake in tiny discrete nodules and in multinodular goiter, and is a better guide to the physician in fine-needle aspiration of the cold areas.

Female↗
PubMed1997

Liver hemangioma. A perioperative Tc-99m RBC SPECT correlation.

Scintigraphic diagnosis of a liver hemangioma may be difficult when its size approaches the spatial resolution of a gamma camera, and it may not be visualized on a Tc-99m tin-colloid liver SPECT study. The contribution of Tc-99m labeled RBC scintigraphy is shown in a patient with a liver hemangioma discovered during laparoscopic cholecystectomy for chronic cholecystitis. Despite negative CT, US, and Tc-99m tin-colloid SPECT of the liver, Tc-99m labeled RBC SPECT disclosed a focus of increased activity consistent with the hemangioma.

Colloids↗
PubMed1996

Cerebral hypoperfusion in medication resistant, depressed patients assessed by Tc99m HMPAO SPECT.

Functional imaging studies generally show decreased cerebral metabolism and perfusion in depressed patients relative to normal controls, although the location of the deficits varies. We used Tc99m HMPAO SPECT to compare cerebral blood flow in medication resistant, depressed patients and a normal control group. HMPAO uptake ratios (adjusted for age) were significantly lower in the depressed patients in the transaxial slices 4 cm and 6 cm above the orbitomeatal line (OML) on the left side. Examining individual regions of interest (corrected for age and multiple testing), we found significantly lower perfusion in the left superior temporal, right parietal and bilateral occipital regions in the patient group. These findings are in limited agreement with previous HMPAO SPECT studies. Methodological differences between studies, particularly variability in adjusting data for age, lead to a divergence in findings. Future research should seek to standardize protocols and data analysis in order to generate comparable results.

Adult↗
PubMed1996

A 31P NMR study of preconditioned isolated perfused rat heart exposed to intermittent ischemia.

Exposure to a short ischemic period (ischemic preconditioning, IP) will protect the heart from damage following a subsequent longer ischemic episode. The aim of the study was to test whether IP is cardioprotective in the setting of repeated ischemia-reperfusion cycles. Thus, Langendorff-perfused hearts, exposed to IP, were subjected to three consecutive ischemia-reperfusion (10/15 min) cycles. Myocardial energetics, manifested by 31P NMR spectroscopy, was correlated with hemodynamics. ATP recovery was significantly higher for the IP group compared with control (P < 0.02) during reperfusions. However, there was no significant difference in ATP recovery during the three ischemic intervals. The supernormal recovery of phosphocreatine recorded during reperfusion was lower for the IP group (approximately 120%) compared with control (approximately 135%, P < 0.065). Better recovery of the left ventricular-developed pressure was noted during reperfusions for the IP group and became significant only during the last reperfusion (86% versus 68%, P < 0.025). In conclusion, the above results support prolonged IP cardioprotection.

Adenosine Triphosphate↗