摘要:

Purpose:Tl-201 myocardial perfusion SPECT is commonly used to assess myocardial perfusion and viability. Nitrate-augmented redistribution with repeated injection facilitates the detection of reversible segments compared with standard redistribution. In this study, we investigated the potential of nitrate augmentation to improve myocardial perfusion and viability assessment without repeated injection and we also compared nitrate-augmented redistribution with delayed redistribution.Methods:Eighteen patients underwent a stress-redistribution Tl-201 SPECT study. Immediately after redistribution SPECT, each patient was administered 0.6 mg glyceryl trinitrate and nitrate-augmented redistribution SPECT acquired 30 minutes later. Each patient then returned the next day and was injected with a booster dose of Tl-201 30 minutes before the delayed redistribution SPECT acquisition. For each SPECT study, the myocardium was divided into 11 segments, and perfusion to each segment was scored on a four-point scale by consensus. An overall cardiac perfusion score was derived by summing the perfusion score for each segment.Results:Reduced stress perfusion was identified in 150 segments: 23 (15.3%) had improved perfusion after redistribution; 60 (40%) segments had improved perfusion after nitrate-augmented redistribution; 52 (34.7%) segments with reduced stress perfusion had improved perfusion after delayed redistribution. The cardiac perfusion score after stress was 15.9 ± 5.5 (means ± SD). The score increased to 17.4 ± 5.4 after redistribution. The perfusion score improved to 19.7 ± 5.8 (P< 0.05 versus redistribution) after nitrate augmentation. The cardiac perfusion score, 19.2 ± 6.4, did not improve further after delayed redistribution.Conclusions:Tl-201 SPECT with nitrate-augmented redistribution is as good or better than delayed redistribution with repeated injection for myocardial perfusion and viability assessment. Tl-201 SPECT with nitrate-augmented redistribution has significant logistical and economic advantages over traditional delayed redistribution with Tl-201 repeated injection.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:Renovascular hypertension is an unusual cause of elevated mean arterial pressure in children. When suspected, angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy is usually one of the initial studies done to evaluate patients. The accuracy of this test depends not only on patient selection but also on technical factors involved in performing the study. We report a case of a false-positive angiotensin-converting enzyme inhibitor-enhanced radionuclide renogram in a 5-year-old boy with hypertension.Methods:Angiotensin-converting enzyme inhibitor-enhanced renal scintigraphy was performed and the result was interpreted as positive for bilateral renovascular disease. A review of the anesthesia record from the study revealed that the patient was hypotensive. A repeated study with adequate hydration and blood pressure stability was then done.Results:The result of the second examination was interpreted as normal, without evidence of abnormal renovascular physiology.Conclusions:The cause of the initial false-positive result was determined to be dehydration with secondary hypotension. Dehydration, with secondary hypotension, can cause a diminished glomerular filtration rate and mimic bilateral renovascular physiology on angiotensin-converting enzyme inhibitor-enhanced renal scans.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:Bone scanning is the most common diagnostic imaging service requested by Australian rheumatologists, who order $50,000 (Australian) worth of bone scans annually.Methods:To determine why rheumatologists request bone scans and how they affect their patient management, the authors administered a two-part prospective survey before and after every bone scan ordered by four rheumatologists during a 6-month period in 1996.Results:A total of 136 bone scans were requested. The primary indications for scanning were to confirm a clinical diagnosis (38%), to exclude a diagnosis (34%), and to localize the site of pain (17%). The common diseases that rheumatologists were attempting to confirm or exclude with bone scanning were inflammatory arthritis, malignancy, and fracture. However, the most common provisional and final diagnosis was soft tissue rheumatism (18%), followed by inflammatory arthritis (15%) and osteoarthritis (11%). Bone scans were successful in excluding a diagnosis in 87% and confirming a diagnosis in 80%. In 32%, bone scans altered the clinical diagnosis, and in 43% they changed the course of disease management. Bone scan results prevented further investigations in 60%.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Bone scan flare seriously complicates evaluations of the therapeutic response of bone metastases. The value of bone metabolic markers in monitoring the therapeutic response for bone metastases in breast cancer was assessed. Twenty-three breast cancer patients with bone metastases treated by combined chemotherapy of cyclophosphamide, doxorubicin, and 5-fluorouracil (CAF) were monitored using bone scans; a bone resorption marker, pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP); a bone formation marker, bone-specific alkaline phosphatase (BAI-p); and a tumor-specific marker (CA15-3). Bone scans were performed before and 3 or 4 months after therapy. After CAF therapy, markers were measured monthly. As a control, the markers of nine patients without bone metastases who received adjuvant CAF therapy were also measured monthly. The therapeutic effect on bone metastases was assessed after the study. Five patients had progression of disease (PD), three had no change (NC), and 15 patients had partial responses (PR). Bone scan flare-up was seen in five PR patients. In patients who received adjuvant therapy, ICTP, BAl-p, and CA15-3 did not change. ICTP increased significantly in PD patients. ICTP did not increase in either NC or PR, including bone scan flare patients. BAl-p and CA15-3 did not show any discernible pattern among PD, PR, flare, and NC patients. Thus measuring ICTP could distinguish PD from NC or PR patients' responses to CAF therapy. This was true also for patients who showed bone scan flare-up. Measuring a bone resorption marker, ICTP, allows clinicians to monitor patients' responses to CAF therapy and may prevent prolonged ineffective therapy or unnecessary changes in therapy as a result of the flare phenomenon.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:To assess the use of Tc-99m sestamibi to localize recurrent and metastatic parathyroid carcinoma.Methods:A patient with a history of parathyroid carcinoma that was resected 6 months before had high serum calcium and high serum parathyroid hormone levels. Tc-99m sestamibi imaging was performed to localize the recurrence.Results:Tc-99 sestamibi imaging detected the recurrence and the metastatic lymph nodes. These findings were confirmed surgically and pathologically.Conclusion:Tc-99m sestamibi can be useful in diagnosing and localizing metastatic parathyroid carcinoma.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:This report illustrates the potential diagnostic and therapeutic utility of somatostatin receptor scintigraphy and therapy with somatostatin.Methods:In-111 pentetreotide (In-11 octreotide), a somatostatin analog, was used to define the receptor status and the extent of disease in a case of malignant thymoma.Results:Subsequent treatment with nonradioactive somatostatin inhibited tumor growth.Conclusion:In-111 octreotide may be usfeul to define tumor receptor status and may provide prognostic information useful in determining subsequent therapy.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:In normal aging persons, oxygen and glucose consumption progressively decreases with reduced cerebral blood flow (CBF), which could be responsible for age-related changes in cognitive functions. A data processing model with the use of Tc-99m SPECT of the human brain has been developed and found to be sensitive for monitoring the effects of drugs that increase CBF. In this study, the effect of two vasodilator drugs (the combination of pentifylline and nicotinic acid versus piracetam) was compared with the effect of placebo on CBF.Materials and Methods:Thirty elderly volunteers had three different procedures using the Peelproc method to spatially standardize and compare CBF patterns by SPECT before and after drug intervention. The 30 patients were divided into five groups of six persons each who were randomly assigned in a 1:1 ratio to the treatment sequences consisting of three phases: the combination of pentifylline and nicotinic acid (C), piracetam (N), and placebo (P), or C-N-P; P-N-C; P-C-N; N-C-P; C-P-N; or N-P-C. Phases 1 to 3 each consisted of a baseline recording of parameters (day 0), treatment for 60 days (days 1 to 60), and recording of parameters after treatment (day 61).Results:In elderly human volunteers (ages, 52 to 70 years), after 2 months of oral treatment with a combination of pentifylline and nicotinic acid (800 mg pentifylline, 200 mg nicotinic acid daily), SPECT results for the Peelproc program indicated a statistically significant improvement in CBF of the total brain, with a more pronounced improvement in the cerebellum and frontal regions, where a definite shift from abnormal to normal blood flow was detected. Spontaneous communication from most of the volunteers suggested that they experienced an improvement in memory and general well-being from the combination treatment. After 2 months of oral treatment with piracetam (2.4 g daily) in elderly human volunteers, SPECT results indicated a regional improvement in CBF, particularly in the cerebellum. However, no beneficial effects with this drug were spontaneously reported.Conclusion:Thein vivomethod to quantitatively monitor the progress of long-term drug therapy on CBF described here could be useful to assess and even direct changes in therapy.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:This study was done to evaluate the accuracy of radionuclide dipyridamole stress imaging to detect multivessel disease and ischemia in segments of myocardium supplied by the most stenotic vessel.Methods:A retrospective analysis of consecutive patients with known triple-vessel disease of at least 50% stenosis in each of the three major epicardial coronary arteries who had exercise (n = 44) or dipyridamole (n = 86) stress testing, or both, within 6 months of coronary angiography.Results:The accuracy of dipyridamole stress testing to detect three-vessel disease was 52% and ischemia was detected in the region supplied by the most stenotic vessel in 67% of patients. The sensitivity and specificity rates of radionuclide imaging to detect ischemia in the region supplied by the vessel of tightest stenosis were 69% and 74% for the left anterior descending coronary artery (LAD), 61% and 78% for the right coronary artery (RCA), and 61% and 57% for the left circumflex coronary artery (LCX). Based on these values, in 39% of patients in whom the RCA or LCX was the most stenotic vessel and in 31% of patients in whom the LAD was the most stenotic vessel, perfusion defects were not present on their nuclear scans.Conclusions:These results have important implications for interventional cardiologists who perform angioplasty on the most stenotic vessel, because the regions supplied by these vessels may not be the most ischemic. Furthermore, dipyridamole stress imaging may significantly underestimate the number of patients with substantial three-vessel coronary artery disease when qualitative imaging is done.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Purpose:This study evaluated the feasibility, hemodynamic responses, and relation of combined Tc-99m sestamibi SPECT imaging and first-pass radionuclide angiography during the infusion of a new β agonist arbutamine.Methods:Arbutamine was administered to 15 patients and constantly adjusted by a closed-loop computerized system. Rest and arbutamine Tc-99m sestamibi radionuclide angiography was performed with a multicrystal gamma camera followed by SPECT imaging with a rotating triple-head, single-crystal gamma camera.Results:The mean differences (paired t-test) between rest and arbutamine studies for heart rate (HR), end-diastolic volume (EDV), stroke volume (SV), cardiac output (CO), and ejection fraction (EF) were as follows: 55 bpm for HR (P< 0.001), 5 ml for EDV (P= ns), 7.5 ml for SV (P= 0.04), 4.4 l/min for CO (P< 0.001), and 6.4% for EF (P< 0.001), respectively. The results of SPECT studies were abnormal in six patients and normal in nine. Findings of radionuclide angiography were normal in 12 patients and abnormal in three. Interpretation of the perfusion and functional studies were concordant in 10 and discordant in five patients.Conclusions:Simultaneous cardiac radionuclide angiography and SPECT imaging are feasible during arbutamine infusion. This potent β agonist increases cardiac output through a chronotropic effect with no significant changes in EDV. The discordance in SPECT and radionuclide angiography results may represent incremental diagnostic and prognostic information provided by both studies.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Clinically detectable well-differentiated metastatic thyroid cancer to the kidney is rare, with only 12 cases reported in the medical literature. The authors report a case of metastatic thyroid carcinoma to the kidney in a patient with widespread dissemination. She underwent total thyroidectomy, radical left nephrectomy, radioactive ablation with I-131, radiotherapy, and thyroid suppression therapy. Well-differentiated thyroid metastatic cancer can be amenable to treatment with successful long-term results.

ISSN:0363-9762    

出版商:OVID    

年代:1999

数据来源: OVID