In vitro accumulation of technetium-99m-sestamibi in human parathyroid mitochondria.

BACKGROUND: Technetium-99m-sestamibi (sestamibi) is the imaging agent of choice for preoperative parathyroid localization. The subcellular localization of sestamibi uptake in enlarged parathyroid glands in patients with hyperparathyroidism has not been determined. This study investigated the mechanism of retention of sestamibi by human parathyroid tissue. METHODS: Twenty-three freshly harvested and 15 cryopreserved parathyroid glands excised from patients with primary or secondary hyperparathyroidism were analyzed for subcellular localization of Tc-99m-sestamibi. Tissues were incubated with 100 microCi of sestamibi and isolated for mitochondria by differential centrifugation, and the integrity of subcellular fractions was quantified with the mitochondrial enzyme marker, succinate dehydrogenase. RESULTS: Ninety-two percent of sestamibi activity was associated with mitochondria. Furthermore, after adding the mitochondrial uncoupler, carbonylcyanide m-chlorophenylhydrazone (CCCP), to fresh parathyroid tissues, 84.96% and 73.86% of sestamibi was released from the mitochondrial and tissue fragment components, respectively. In addition, sestamibi activity in the mitochondrial component of cryopreserved human parathyroid tissue decreased to the same amount as the CCCP-treated group. CONCLUSIONS: These data confirm that mitochondrial activity is the major component of sestamibi uptake by human parathyroid tissue in patients with hyperparathyroidism.

Asymptomatic large main pulmonary artery thromboembolism with a low-probability ventilation-perfusion lung scan.

The incidence of the interpretation of low-probability lung scans in asymptomatic patients with large central pulmonary embolisms and the prognostic implication of the ventilation-perfusion scan appearance in this clinical setting is not documented.

Antagonistic behavior, dominance, hostility, and coronary heart disease.

PURPOSE: This study investigated the relationship between antagonistic behavior, dominance, attitudinal hostility, and coronary heart disease (CHD). METHODS: One hundred one men and 95 women referred for thallium stress testing were administered the Structured Interview and the Cook-Medley Hostility Scale. The Hostile Behavior Index, derived from the Structured Interview and developed by Haney et al., served as an index of antagonism, and the frequency with which interviewees interrupted their interviewer served as a measure of dominance. On the basis of their medical history and thallium stress test results, patients were classified as having (N = 44) or not having (N = 99) CHD. RESULTS AND CONCLUSIONS: Multivariate logistic regressions (with age, gender, disease, and lifestyle risk factors in the model) revealed that both the Hostile Behavior Index and dominance were significant independent risk factors for CHD (relative risk [RR] = 1.22 and 1.47, p < .03). Of the two Hostile Behavior Index component scores, indirect challenge and irritability, only the latter correlated significantly with CHD (RR = 1.27, p < .03). Separate logistic regressions for men and women suggest that subtle, indirect manifestations of antagonism confer CHD risk in women and that more overt expressions of anger confer risk in men. A significant univariate correlation between hostility scale scores and CHD became not significant when we adjusted for socioeconomic status.

Use of technetium Tc 99m sestamibi scintigraphy for recurrent tertiary hyperparathyroidism from a parathyroid forearm graft.

Technetium Tc 99m sestamibi scintigraphy is a sensitive technique for localizing recurrent parathyroid disease in the neck or mediastinum. We report the case of a 60-year-old woman with recurrent tertiary hyperparathyroidism after total parathyroidectomy. Technetium Tc 99m sestamibi images of the neck and mediastinum were negative; however, images of the right arm revealed a hyperfunctioning parathyroid autotransplant. Partial resection of the autograft resulted in prompt resolution of the hyperparathyroidism.

The value of a baseline bone scan in patients with newly diagnosed prostate cancer.

PURPOSE: This study evaluated the role of bone scans in managing newly diagnosed, untreated prostate cancer. METHODS: Two hundred seventy consecutive staging bone scans in patients (mean age, 69 years) with newly diagnosed prostate cancer who had serum prostate-specific antigen (PSA) determinations and biopsies between January 1995 and October 1997 were evaluated retrospectively. RESULTS: The bone scans were positive for metastatic bone disease in 24 patients and negative in 246. Serum PSA levels, the number of positive biopsy cores, the extent of tumor in the prostate gland, and Gleason scores were all significantly correlated with scintigraphic bone metastases (P < 0.0001 for each). Of the 177 patients with PSA levels less than 10 ng/ml, three had bone metastases. Bone metastases were found in 2 of 34 patients with PSA levels of 10.1 to 20 ng/ml, in 3 of 29 patients with PSA values of 20.1 to 50 ng/ml, and in 16 of 30 patients with PSA levels greater than 50.1 ng/ml. Only one patient had a bone metastasis when the prostate cancer involved fewer than 2 biopsy cores (1 of 135) or when disease was confined to one lobe (1 of 131), but the incidence increased significantly when the malignancy involved three or more biopsy cores (20 of 114) or disease was present in both prostate lobes (20 of 118). Four of 160 patients with Gleason scores less than 6 had bone metastases, whereas 20 of 110 patients with Gleason scores greater than 7 had bone metastases. CONCLUSIONS: The likelihood of bone metastases is low in patients with newly diagnosed, untreated prostate cancer when the initial PSA level was less than 10 ng/ml, the number of positive biopsy cores was less than 2, tumor was confined to one lobe, or the Gleason score was less than 6. However, none of these criteria can be used to exclude metastatic bone disease. A baseline bone scan is an important staging procedure and should be obtained to provide maximum data for clinical management of the disease.

Dimensions of anger and CHD in men and women: self-ratings versus spouse ratings.

One hundred one males and 95 females referred for thallium stress testing were administered Spielberger's State-Trait Anger Expression Inventory (STAXI), the Ho scale cynicism items, the Cynical Beliefs Scale, and Bendig's Manifest Anxiety Scale. A subset of 53 males and 43 females was rated by their spouses by means of STAXI. Based on the thallium findings and their medical history, patients were classified either as healthy, or as having documented CHD, or as questionable. Patients' STAXI and cynicism measures were submitted to a principal-components analysis which yielded three factors: Impulsive Anger-out. Inwardly experienced anger, and Cynicism. The relationships between factor scores and documented CHD was determined by means of logistic regression analyses. Only Impulsive Anger-out correlated (positively) with CHD, but only when based on spouses' ratings and only in males (p < .01, RR = 3.13). Covarying traditional risk factors and cynicism did not attenuate this relationship. However, a significant relationship between Ho scale cynicism and CHD did not survive adjustment for traditional risk factors. Anxiety was not a risk factor for CHD.

Gamma probe-directed biopsy of the sentinel node in oral squamous cell carcinoma.

OBJECTIVE: Management of the N0 neck in head and neck squamous cell carcinoma is an important issue for the head and neck surgeon. Experience with radionuclide-labeled colloid injection to identify a sentinel node in malignant melanoma suggests a high level of accuracy for this approach to identify microscopic metastasis when present. We set out to explore the feasibility of using the handheld gamma probe to identify radiolabeled sentinel nodes in oral squamous cell carcinoma. PATIENT POPULATION: Five individuals with N0 necks and accessible oral or oropharyngeal primary sites from a major tertiary referral center. METHODS: Radiolabel with unfiltered technetium Tc 99m sulfur colloid was injected in quadrants around the primary site followed by immediate dynamic lymphoscintigraphy. Open biopsy of the sentinel node was accomplished within 2 hours of injection after extirpation of the primary site. Regional or complete neck dissection was performed after sentinel node biopsy. RESULTS: Sentinel node biopsy accurately identified one or several nodes in 2 cases, including nodes containing metastatic cancer in 1. In the other 3 cases, the radiolabel failed to identify the sentinel node despite the presence of metastatic disease in the nodes at final pathologic study in 2. CONCLUSIONS: Detection and biopsy of the sentinel node are feasible for selected patients with oral head and neck squamous cell carcinoma with N0 necks. There is a potential savings of time, cost, and morbidity with this approach. However, several substantial problems were encountered with the technique in this limited series of patients. Establishing the reliability of lymphoscintigraphy in this setting would require testing in a much larger patient cohort. Our experience suggests that such an investment may not be warranted.

Longer occupancy of opioid receptors by nalmefene compared to naloxone as measured in vivo by a dual-detector system.

UNLABELLED: Surgical procedures usually involve the administration of narcotic drugs as anesthetics or adjuvants. To reverse the effects of anesthesia, opioid antagonists such as naloxone are commonly used. Due to its short lasting effects, patients receiving naloxone must be monitored carefully. Nalmefene, a pure opiate antagonist with a longer duration of action than naloxone, has shown promise in the reversal of opioid anesthesia. METHODS: A simple dual-detector positron radiation detector system and [11C]carfentanil were used to compare the duration of blockade of cerebral mu opioid receptors by naloxone and nalmefene in eight normal volunteers. Carbon-11-carfentanil brain kinetics were monitored for 5 min and 2, 4, 8 and 24 hr after the administration of either nalmefene (1 mg or 1 microg/kg) or naloxone (2 mg or 2 microg/kg). Blood samples were obtained at the same times for plasma determinations. RESULTS: Clearance half-times from opioid receptors were 28.7 +/- 5.9 hr for 1 mg of nalmefene and 2.0 +/- 1.6 hr for 2 mg of naloxone. Brain clearance times were about 21.1 and 3.4 times slower than plasma clearance times for nalmefene and naloxone, respectively. CONCLUSION: These findings suggest that the prolonged effects of nalmefene are related to the slow dissociation of nalmefene from opioid receptors, which are not reflected in the plasma curve. This longer blockade of opioid receptors by nalmefene represents an advantage in the clinical management of postsurgical reversal of narcotic anesthesia and opioid side effects as well as the reversal of opioid overdose.

Clinicopathological correlation of technetium bone scan in vascularization of hydroxyapatite implants. A primate model.

OBJECTIVES: To report the histopathological and bone scan characteristics of the stages of hydroxyapatite fibrovascular integration and to consider the implications for the timing of peg drilling in a primate model. DESIGN: Three monkeys received hydroxyapatite implants covered only anteriorly with a fascia lata button to which the rectus muscles were sutured. Weekly bone scans were evaluated quantitatively and qualitatively. The orbits were harvested at 2, 4, and 8 weeks and examined histopathologically. RESULTS: Quantitatively, the implant's technetium uptake increased, then reached a plateau by 4 weeks. Peripheral uptake was present on the images and histologically at 2 weeks. When bone scan images suggested complete vascularization by the fourth week, the implant was 99% vascularized histologically. Completion of vascularization was ascertained at 8 weeks, without further discernible changes in the bone scans. CONCLUSIONS: The technetium bone scan is sensitive to the vascularization of the hydroxyapatite implant and discerns when complete vascularization is approached. This primate study models closely the clinical findings we have recently reported. We advocate at least a 4-week interval between the time the bone scan suggests full vascularization and peg drilling.

Resting Tl-201 scintigraphy in the evaluation of myocardial sarcoidosis.

In patients with sarcoidosis, myocardial involvement is common and may be fatal. With extensive disease, the primary manifestations may include conduction abnormalities and arrhythmias, which may lead to sudden death. Myocardial perfusion scintigraphy may be the most accurate method to assess extent of myocardial involvement and response to therapy.

Quantitative measurement of vascularization and vascular ingrowth rate of coralline hydroxyapatite ocular implant by Tc-99m MDP bone imaging.

Complete fibrovascular ingrowth of the hydroxyapatite ocular implant is necessary for peg drilling, the secondary procedure that couples the mobile sphere to the ocular prosthesis providing it with motility. This study was conducted to determine the usefulness of the bone scan for the evaluation and relative quantification of the vascularization of coralline hydroxyapatite ocular implants. In 23 patients (32 scans), vascularization of the ocular implant was measured by three-phase bone scintigraphy. There were 16 patients with left, and 7 with right orbital implants. At followup 0.5 to 8 months after successful hydroxyapatite implantation, the mean implant to normal intraorbital activity ratio on delayed bone scans in anterior view was 2.73 +/- 0.73 (mean +/- SD) with a range of 1.42-4.2. The normal right to left and left to right intraorbital bone activity ratios determined in anterior view from 10 normal delayed bone scans were 0.98 +/- 0.05 (mean +/- SD) and 1.02 +/- 0.05 (mean +/- SD) respectively, with a range of 0.93-1.07. The difference of the activity (count) ratios among the successfully implanted group and normals was statistically significant (P < 0.0001). A hydroxyapatite ocular implant to contralateral intraorbital bone activity ratio of greater than 1.12 with a homogeneous tracer distribution throughout the implant suggests adequate and diffuse vascularization is present. The progressive increase in activity ratio of the orbital implants seen in the early postimplantation period, which is indicative of the progression of vascularization, reaches a plateau after 1 month and remains relatively stable thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Misperfusion of the liver during hepatic artery infusion chemotherapy: value of preoperative angiography and postoperative pump scintigraphy.

OBJECTIVE: One purpose of this study was to determine if patients who have anatomic variations in their hepatic arteries are at increased risk for complications associated with the use of intrahepatic arterial infusion pumps. We also tried to determine the value of perfusion studies obtained with 99mTc-microspheres or 99mTc-macroaggregated albumin in detecting postoperative hepatic or visceral misperfusion and in predicting complications in patients with anatomic variants despite pre- or intraoperative attempts to correct the arterial abnormality. SUBJECTS AND METHODS: We prospectively compared findings on scintigrams obtained after delivering the radionuclide through intrahepatic arterial infusion pumps with anatomic variations in hepatic arteries seen on celiac and superior mesenteric hepatic arteriograms obtained before placement of the pump in 49 consecutive patients with colon carcinoma metastatic to the liver. RESULTS: Despite pre- or intraoperative attempts to correct arterial abnormalities to ensure optimal perfusion of the liver in 24 patients with hepatic arterial anomalies seen on preoperative arteriograms, only two patients had normal findings on postoperative perfusion studies performed with 99mTc-microspheres and/or 99mTc-macroaggregated albumin. Abnormalities included perfusion of extrahepatic organs, including the spleen in 12 patients, stomach in seven, bowel in four, and pancreas in three. Eight patients had no perfusion of the left lobe of the liver, and three had no perfusion of the right lobe. Two patients had minimal or no perfusion of both lobes. In 23 of 25 patients with no demonstrable variations in vascular anatomy on preoperative celiac and superior mesenteric arteriograms, findings on hepatic pump scintigrams were normal. Of the 24 patients with abnormal scintigraphic findings, 20 had subsequent clinical complications. However, only two of the 25 patients with normal scintigraphic findings had clinical complications. CONCLUSION: Our results indicate that patients with anatomic variations in the hepatic arterial system are at high risk for misperfusion during chemotherapy despite pre- or intraoperative efforts to alter the perfusion for chemotherapeutic agents delivered by intrahepatic arterial infusion pumps. Misperfusion can be detected by using pump scintigraphy, and therefore patients should be closely monitored with 99mTc-macroaggregated albumin perfusion studies to ensure successful delivery of the chemotherapeutic agents and to avoid serious clinical complications caused by inadvertent perfusion of other organs.

Estimating renal function from the visual analysis of Tc-99m DTPA images.

Eleven visual parameters of Tc-99m DTPA imaging studies were evaluated to identify scintigraphic findings that best detect changes in renal function, to determine at which GFR levels they appear, and to establish criteria for visual estimation of renal function. Visual parameters were compared to in vitro GFR determinations in 41 patients. Three visual parameters offered best discrimination. The first one appeared at GFR values below 70 mL/min (sensitivity: 76%). The renal peak activity on the flow study (normally equal or greater than aortic) no longer reached the intensity of the aortic peak (pK < pA). The second parameter appeared at GFR values below 50 mL/min (sensitivity: 85%). The estimated kidney-to-liver ratio in the 2-minute image (usually 3 or greater) decreased to values less than 3. The third scintigraphic finding, pelvicalyceal system nonvisualization, appeared at GFR levels below 20 mL/min (sensitivity 100%). Use of these 3 scintigraphic findings allows categorization of patients into four functional groups: 1) severe dysfunction (GFR: 0-20 mL/min), 2) moderate to severe dysfunction (GFR: 21-50 mL/min), 3) moderate dysfunction (GFR: 50-70 mL/min), and 4) Normal study (GFR > 70 mL/min). Visual analysis of Tc-99m DTPA images does not identify patients with mildly decreased renal function (GFR: 70-90 mL/min).

Detection of left anterior descending coronary artery disease in patients with left bundle branch block.

The detection of coronary artery disease is difficult if a patient has electrocardiographic evidence of left bundle branch block (BBB). Septal blood flow may be reduced in patients with left BBB, despite no angiographic evidence of left anterior descending (LAD) coronary artery disease. We have developed a new method of quantification of Thallium-201 single-photon emission computed tomographic (SPECT) images with the aim of better separating patients with left BBB and LAD disease from those with left BBB alone. The study cohort comprised 8 normal subjects (group I) and 20 patients with left BBB and chest pain who underwent thallium-201 SPECT imaging and coronary angiography. Eight patients (group II) had < or = 50% LAD stenosis, and 12 (group III) had > or = 70% LAD stenosis. Septal abnormality scores on the second short-axis slice from the base were computed, based on comparison of each subject's short-axis circumferential profile with a normal reference curve. This followed a procedure in which each profile was scaled to minimize differences in its absolute level in relation to the reference curve. Septal abnormality scores on stress images were 0.8 +/- 22 for group I, 27 +/- 43 for group II, and 165 +/- 67 for group III (p = 0.15 for group I vs II, and p < 0.0001 between groups I and III, and II and III).(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive assessment of myocardium at risk by Tl-201 SPECT imaging in a child with Kawasaki disease. A case report.

Serial two-dimensional echocardiograms documented the formation of giant aneurysms, measuring from 0.55 to 3.1 cm in diameter, in the distribution of the left and right coronary arteries, in a 2 1/2-year-old boy with Kawasaki disease. His global left ventricular function, assessed by M-mode echocardiography, was normal, and no significant wall motion abnormalities could be detected on two-dimensinal evaluation. Cardiac catheterization showed multiple aneurysms with no evidence of stenosis. Although he had no clinical symptoms or electrocardiographic evidence of ischemia, pharmacologic stress and delayed Tl-201 SPECT images revealed prominent stress-induced myocardial ischemia in the left ventricle. A resting gated blood pool study showed hypokinesia in corresponding regions of the left ventricle. This case demonstrates the usefulness of Tl-201 myocardial SPECT imaging and resting gated blood pool studies in the management of coronary artery disease in children with Kawasaki disease.

Rest thallium-201 myocardial perfusion imaging in a patient with leukaemic infiltration of the heart.

Despite the high incidence of leukaemic infiltration of the heart, only 8 cases of atrioventricular block due to leukaemia have been reported in the literature. Improvement in the heart block associated with disappearance of the leukaemic infiltrate has not been reported. A rest thallium-201 study was used in a 65-year-old man to demonstrate leukaemic infiltration of the heart which was associated with complete heart block. After chemotherapy, when the tumour burden was reduced and the leukaemia in remission, his heart block resolved, and a follow-up thallium scan was normal.