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PubMedDate not supplied

Technetium-99m sestamibi scintimammography complements mammography in the detection of breast cancer.

Mammography remains the technique of choice for the detection of early breast cancer. The sensitivity of mammography is 85%, but is decreased in patients with dense breasts. Sestamibi scintimammography (SCM) has been suggested as an adjunctive modality to improve the detection of breast cancer. We conducted a study to determine the impact of SCM in patient management. A prospective study was conducted in 95 patients presenting with palpable masses and/or abnormal mammography scheduled for biopsy. Injection of 20-30 mCi of technetium-99m (Tc-99m) sestamibi into a pedal vein was performed. Ten-minute images of the breast and axilla were obtained in multiple projections. The mammography and SCM were correlated with pathology and clinical findings. The median age was 44 years (range 28-86 years). The total number of lesions was 104, as eight patients had bilateral lesions and one patient had two lesions in the same breast. Fifty-nine patients presented with palpable lesions and 45 patients with nonpalpable lesions (42 with abnormal mammography only and 3 with nipple discharge). A comparison of sensitivity, specificity, positive and negative predictive values, and overall accuracy of SCM and mammography were performed. The sensitivity and specificity for SCM were 83% and 83%, respectively, and for mammography were 65%, and 72%, respectively. The sensitivity and specificity for combined SCM and mammography were 87% and 94%, respectively. The p-value for mammography versus combined SCM and mammography was 0.0003 and that for SCM versus SCM and mammography was 0.0098. There were 80 (77%) benign and 24 (23%) malignant lesions. Of the 24 malignancies, SCM missed six (25%), versus eight (33%) by mammography. In two patients (9%) SCM detected malignancy in the breast that was not visualized by mammography or found on clinical examination. Sestamibi SCM improves the sensitivity of mammography and it detects up to 9% of malignancies not detected by mammography or clinical examination. This testing could impact the management of 16,500 patients in the United States every year. More studies are needed to better define its role in breast cancer detection.

Adult↗
PubMedDate not supplied

Intraoperative sentinel node identification with Technetium-99m-labeled nanocolloid in patients with cancer of the uterine cervix: a feasibility study.

The objective of this study is to determine the feasibility of intraoperative lymphatic mapping in patients with cervical carcinoma. Patients with early-stage cervical cancer, scheduled to undergo a Wertheims radical hysterectomy and pelvic lymphadenectomy, were eligible for the study. Technetium-99-m-labeled nanocolloid was injected intracervically at two locations around the tumor 3-6 hours before the operation. Images were recorded immediately and 2.5 hours later using a gamma camera. During the operation sentinel nodes (SLN) were identified using a handheld or laparoscopic gamma-detection probe (Navigator, Auto-Suture). After resection of the SLNs a standard pelvic (and para-aortic) lymphadenectomy was performed. The results of the histopathology of SLNs and non-SLNs were compared. The procedure was well tolerated by 24 of 25 patients. One or more SLN could be identified in 21 out of 25 patients. In one patient who was preoperatively irradiated, in two patients who had had a cone biopsy, and in one patient without previous interventions, no SLN could be detected. The mean time for identification was 5 minutes. In 16 patients, pathologic examination showed no metastatic disease in both SLNs and non-SLNs, whereas metastases were found in the SLN in five patients (in one case only SLN involved, four cases SLN and respectively 3, 11, 22 and 31 other positive nodes). This study shows that identification of SLNs in cancer of the uterine cervix is feasible with preoperatively administered 99mTc-labeled nanocolloid. To date, no false negative SLNs have been found, but expansion of the study is necessary to determine possible clinical application of this new technique.

Adenocarcinoma↗
PubMed2001

Resting echocardiography and quantitative dipyridamole technetium-99m sestamibi tomography in the identification of cardiac allograft vasculopathy and the prediction of long-term prognosis after heart transplantation.

AIMS: To evaluate the accuracy of echocardiography in conjunction with quantitative high-dose dipyridamole technetium-99m sestamibi tomography (SPECT) in detecting coronary allograft vasculopathy. METHODS AND RESULTS: Seventy-eight consecutive heart transplant recipients underwent echocardiography while at rest and high-dose dipyridamole SPECT within 48 h of a yearly angiogram. Resting wall motion abnormalities were considered significant if present in two or more segments. SPECT was considered abnormal in the presence of reversible/fixed defects. The coronary angiogram was normal in 53, showed non-significant coronary allograft vasculopathy in 13 and significant (> or = 50% stenosis) coronary allograft vasculopathy in 12 cases. Resting wall motion abnormalities were observed in nine cases and perfusion defects in 20. Echocardiography and SPECT were concordant in 59 cases (five positive and 54 negative); in these, accuracy was 100% for significant coronary allograft vasculopathy and 83% for any coronary allograft vasculopathy. Over 6.5+/-2 years, 17 patients suffered coronary allograft vasculopathy-related events, including death in six and retransplantation in three. Resting wall motion abnormalities, SPECT perfusion defects and angiographic coronary allograft vasculopathy were significant predictors of cardiac events. CONCLUSION: Normal resting wall motion at echocardiography coupled to normal stress myocardial perfusion, rules out the presence of significant coronary allograft vasculopathy in many heart transplant recipients. Conversely, resting wall motion abnormalities and perfusion defects strongly predict cardiac events. Therefore, a strategy which reserves angiography for patients with resting wall motion abnormalities and/or perfusion defects may be safe and cost-effective.

Adolescent↗
PubMed2000

The value of technetium 99 scintigraphy in the prognosis of amputation in severe frostbite injuries of the extremities: A retrospective study of 92 severe frostbite injuries.

We report a retrospective study of the prognostic value of 2-phase technetium 99m bone scanning performed in 92 patients who presented to Chamonix Hospital with severe frostbite of the extremities in the past 12 years. The results of this study show that an initial bone scan (as early as day 3) has excellent specificity in evaluating the severity of frostbite injury. There was a direct correlation between the demarcation zone of uptake in the phalanges and the eventual level of amputation (positive predictive value, 0.84). A second scan on approximately day 7 was even more sensitive and informative. A strong correlation existed between positive uptake and eventual healing (negative predictive value, 0.99). This study showed that (99m)Tc bone scanning in the first few days after frostbite injury indicates the level of amputation in severe frostbite in more than 84% of cases. We propose an algorithm based on the results of this study that can be used to evaluate new medical and surgical management of frostbite injury.

Adult↗
PubMedDate not supplied

Ureteral obstruction after ureteroneocystostomy in dogs assessed by technetium TC 99m diethylenetriamine pentaacetic acid (DTPA) scintigraphy.

OBJECTIVE: To use technetium Tc 99m diethylenetriamine pentaacetic acid (99mTc-DTPA) renal scintigraphy to monitor ureteral obstruction after ureteroneocystostomy in a canine model of partial ureteral obstruction. STUDY DESIGN: Experimental study. ANIMALS: Eight normal adult dogs. METHODS: Partial ureteral obstruction was created in 8 dogs by incomplete ligation of the terminal right ureter. Two weeks later, ureteroneocystostomy was performed in 7 dogs with unilateral partial ureteral obstruction and in 1 dog that had developed bilateral partial ureteral obstruction. 99mTc-DTPA scintigraphy was performed intermittently for 2 weeks after ureteroneocystostomy. Renal transit time of each kidney, as assessed by the time to maximal uptake (time of peak), and glomerular filtration rate, as assessed by percentage of kidney uptake of the radiopharmaceutical between 1 and 3 minutes, were estimated. Comparison between affected and nonaffected kidneys was performed with the Wilcoxon rank sum test. RESULTS: Unilateral partial ureteral obstruction was induced successfully in 7 dogs. In 1 dog, bilateral partial obstruction was induced inadvertently. After ureteroneocystostomy, percentage of kidney uptake of 99mTc-DTPA was low in 4 affected kidneys. The uptake returned to within normal limits in 2 of the kidneys during the observation period. The time activity curve had a more rounded appearance or was increasing continuously for all affected kidneys. A significant increase in renal transit time was observed 2 and 4 days after ureteroneocystostomy. Transit time progressively returned to normal by 4 to 11 days for all affected kidneys except 1. CONCLUSION: Ureteroneocystostomy resulted in persistent partial ureteral obstruction for 4 to 11 days as determined by 99mTc-DTPA scintigraphy. CLINICAL RELEVANCE: 99mTc-DTPA scintigraphy may be a useful procedure for monitoring renal function and ureteral obstruction after ureteroneocystostomy. Persistent partial ureteral obstruction may be seen 1 to 2 weeks after ureteral reimplantation in dogs with previously existing dilated ureters.

Animals↗
PubMed2002

Abdominal scintigraphy using technetium Tc 99m hexylmethylpropylene amine oxime-labeled leukocytes in patients with seronegative spondyloarthropathies.

OBJECTIVE: To assess the potential benefits of technetium Tc 99m hexylmethylpropylene amine oxime (Tc 99m HMPAO)-labeled leukocyte scintigraphy in a group of patients with spondyloarthropathies (SpAs), overt gastrointestinal symptoms, and negative extensive endoscopic/radiologic test results. PATIENTS AND METHODS: Ten patients with SpAs and overt gastrointestinal symptoms were included in this study. All patients underwent colonoscopy and small bowel barium studies, and results were negative. Abdominal scintigraphy with Tc 99m HMPAO-labeled leukocytes was performed in all the patients. Clinical and laboratory data and response to treatment was recorded. RESULTS: The Tc 99m HMPAO-labeled leukocyte scintigraphy was positive in 5 of 10 patients, demonstrating uptake at the terminal ileum which is very suggestive of Crohn disease. The 5 scintigraphically positive patients were treated with sulfasalazine (SSZ). Four patients responded to SSZ with significant improvement of both gastrointestinal and joint symptoms. CONCLUSIONS: In 5 of 10 patients with SpA and suspected inflammatory bowel disease on clinical grounds, evidence of inflammatory bowel disease was shown by scintigraphic studies in which conventional invasive procedures failed. Tc 99m HMPAO-labeled leukocyte scintigraphy should be considered in the evaluation of patients with SpA.

Abdomen↗
PubMed2000

Accuracy of dobutamine technetium 99m sestamibi SPECT imaging for the diagnosis of single-vessel coronary artery disease: comparison with echocardiography.

BACKGROUND: Recent experimental studies have shown that technetium 99m methoxyisobutyl isonitrile (MIBI) underestimates flow heterogeneity induced by dobutamine and that this might have an impact on the sensitivity of dobutamine MIBI in patients with single-vessel coronary artery disease (CAD). This study compares the accuracy of dobutamine MIBI single-photon emission computed tomography (SPECT) and simultaneous echocardiography in the diagnosis of single-vessel CAD. METHODS AND RESULTS: Ninety-one patients (age 57 +/- 12 years) with single-vessel CAD or without significant CAD were studied with dobutamine (up to 40 microg/kg per minute)-atropine (up to 1 mg) stress echocardiography (DSE) and simultaneous MIBI SPECT imaging. CAD was predicted on the basis of myocardial ischemia (transient wall motion abnormalities by DSE and reversible perfusion defects by MIBI). Ischemia was detected by MIBI in 30 of the 54 patients with and in 10 of the 37 patients without significant single-vessel CAD (sensitivity 56%, confidence interval [CI] 45 to 66; specificity 73%, CI 64 to 82; accuracy 63%, CI 53 to 73). Ischemia was detected by DSE in 30 patients with and in 6 patients without significant CAD (sensitivity of DSE 56%, CI 45 to 66; specificity 84%, CI 76 to 91; accuracy 67%, CI 57 to 77, P = not significant vs MIBI). For both imaging methods, sensitivity was significantly higher in patients with left anterior descending than in patients with left circumflex or right coronary artery stenosis (75% vs 40%, P <.05). The addition of echocardiography to MIBI did not improve the diagnostic accuracy (68% CI 59 to 78, P = not significant vs DSE or MIBI alone). CONCLUSIONS: DSE and MIBI SPECT imaging have similar moderate sensitivity for the diagnosis of single-vessel CAD. Sensitivity of each of these techniques is higher in patients with left anterior descending than in patients with left circumflex or right coronary artery stenosis. There is no improvement of diagnostic accuracy by use of the combination of both techniques.

Aged↗
PubMed2000

Infarct size determination by technetium 99m sestamibi single-photon emission computed tomography predicts survival in patients with chronic coronary artery disease.

BACKGROUND: The prognostic value of infarct size quantification by technetium 99m sestamibi single-photon emission computed tomography (SPECT) in patients with chronic coronary artery disease (CAD) has not been established. Methods And Results Between September 1994 and May 1995, 1323 patients with known or suspected CAD were referred for perfusion imaging for clinical reasons and had infarct size determined by quantitative SPECT imaging. Patients underwent exercise stress (61%), pharmacologic stress (37%), and rest imaging (3%). Patients were excluded if they had cardiomyopathy, valvular heart disease, or myocardial infarction within 3 weeks of the SPECT study. There were 1224 patients who formed the study group. Follow-up was 94% complete at a median of 1.9 +/- 0.4 years. Sixty-five percent of patients had no measurable infarct. Among the patients with measurable infarcts, the mean infarct size by sestamibi imaging was 15.0% +/- 14.5% of the left ventricle (25% of infarcts </=5% of the left ventricle and 25% of infarcts >/=19% of the left ventricle). By using stepwise regression analysis, age, diabetes, and hypercholesterolemia were all clinical predictors of overall death (P <.05). For cardiac death, only age and diabetes were significant. After adjusting for these clinical variables, infarct size remained an independent predictor of overall death (P =. 001) and survival free of cardiac death (P =.0002). However, when first-pass left ventricular ejection fraction was added to the models, infarct size was no longer significant. CONCLUSIONS: Infarct size determination by SPECT (99m)Tc sestamibi can predict subsequent death in patients with chronic CAD, although ejection fraction appears to have greater prognostic value.

Adult↗
PubMedDate not supplied

Quantitative thallium-201 and technetium 99m sestamibi tomography at rest in detection of myocardial viability in patients with chronic ischemic left ventricular dysfunction.

BACKGROUND: This study was designed to determine the most effective quantitative threshold for thallium-201 and technetium 99m sestamibi uptake on tomographic imaging after rest injection for the detection of myocardial viability in patients with chronic myocardial infarction. METHODS AND RESULTS: Thallium and sestamibi cardiac tomography at rest was performed in 43 patients with chronic myocardial infarction and impaired left ventricular (LV) function undergoing coronary revascularization. In all patients, echocardiography and radionuclide angiography were performed at baseline and repeated 12 months later to evaluate recovery of regional LV function and LV ejection fraction, respectively. Optimal threshold cutoff points to separate reversible from irreversible dysfunction were determined by receiver operating characteristic analysis. When all dysfunctional segments were considered, the best cutoff point in the identification of reversible LV dysfunction for both thallium and sestamibi activity was 67%. When only akinetic or dyskinetic segments were considered, the best cutoff point in the identification of reversible LV dysfunction was 58% for thallium and 55% for sestamibi. In these segments, the area under the receiving operating characteristic curves constructed for thallium and sestamibi activity were 0.74+/-0.05 and 0.75+/-0.04, respectively (P = not significant). LV ejection fraction was 33%+/-7% at baseline and increased to 37%+/-7% after revascularization (P<.0001). A significant relation between the number of akinetic or dyskinetic but viable myocardial segments and revascularization-induced changes in LV ejection fraction was observed for both thallium (r = 0.60, P<.0001) and sestamibi (r = 0.64, P<.0001) imaging. CONCLUSIONS: In patients with chronic myocardial infarction, quantitative analysis of thallium and sestamibi activity on tomographic imaging at rest predicts recovery of regional and global LV dysfunction after revascularization procedures. The most effective quantitative threshold for detecting reversible LV dysfunction is comparable for thallium and sestamibi tomographic imaging. However, the optimal cutoff point is different for both tracers when all dysfunctional segments are considered or when the analysis is focused only on segments with more severe functional impairment (i.e., akinetic or dyskinetic segments).

Chronic Disease↗
PubMedDate not supplied

Sustained reduction of exercise perfusion defect extent and severity with isosorbide mononitrate (Imdur) as demonstrated by means of technetium 99m sestamibi.

BACKGROUND: The impact of long-acting nitrates on the extent and severity of stress-induced myocardial ischemia is not well described, especially after long-term treatment. METHODS: Forty patients with chronic stable angina and reversible ischemia on an exercise stress myocardial perfusion single photon emission computed tomography (ex-SPECT) were prospectively studied in a 6-week period. At baseline, rest thallium-201/exercise stress technetium 99m sestamibi SPECT was performed, followed by treatment with extended-release isosorbide 5-mononitrate (5-ISMN, Imdur). Follow-up ex-SPECT was performed 5 days and 6 weeks after the initiation of therapy with extended-release 5-ISMN. The exercise treadmill testing (ETT) protocol and exercise duration of the follow-up studies were the same as that of the baseline ETT. Defect extent and severity were analyzed both by means of an automated quantitative method, with CEqual software, and visually, with a 20-segment scoring system (which was also used to derive a summed stress score [SSS]). RESULTS: In the 6-week study period, significant reductions occurred in both the extent and the severity of exercise-induced ischemia by means of quantitative SPECT (13.8% [P<.0003] and 12.7% [P<.0003], respectively). There was no significant change in these variables between stages 2 (day 5) and 3 (6 weeks), indicating no development of tolerance to the nitrate effect. Similar reductions were noted by means of the visual analysis (SSS reduction of 13.0% [P<.002]) in the entire study period. CONCLUSIONS: Patients with chronic-stable-angina treated with a long-acting nitrate demonstrate improvement in myocardial perfusion defect extent and severity in an extended period by means of both visual and quantitative analysis of sequential exercise testing to the same rate-pressure product end point.

Aged↗
PubMedDate not supplied

Nitrate-enhanced gated technetium 99m sestamibi SPECT for evaluating regional wall motion at baseline and during low-dose dobutamine infusion in patients with chronic coronary artery disease and left ventricular dysfunction: comparison with two-dimensional echocardiography.

BACKGROUND: The value of gated single photon emission computed tomography (SPECT) in the assessment of wall motion (WM) in patients with severe perfusion defects and in the evaluation of low-dose dobutamine (LDD)-induced changes is not yet established. In patients with chronic coronary artery disease who have left ventricular (LV) dysfunction, the results of nitrate-enhanced technetium 99m sestamibi (sestamibi) gated SPECT for the evaluation of resting and LDD WM were compared with those of baseline and LDD echocardiography (LDDE). METHODS AND RESULTS: Thirty-seven patients underwent echocardiography and nitrate-enhanced sestamibi gated SPECT within 1 week at rest and during LDD infusion. WM was scored from 1 (normal) to 4 (dyskinetic) by using a 16-segment model. Segments with sestamibi uptake less than 30% were considered unsuitable for WM analysis (36 of 592 segments). Echocardiography was technically unreliable in 10 of 592 segments. The precise agreement between echocardiography and gated SPECT for baseline regional WM was 68.4% (kappa = 0.54), without significant differences for the involved coronary artery territory. The agreement for +/- 1 WM scoring was 96.5% (kappa = 0.94). Contractile reserve during LDD was detected by means of echocardiography in 36% and by means of sestamibi gated SPECT in 33% of baseline asynergic segments. Agreement for detection of WM improvement in response to LDD was 74% (kappa = 0.41). The overall and +/-1 WM score agreement for LDD WM was 67.5% (kappa = 0.50) and 94.7% (kappa = 0.91), respectively. A significant correlation between echocardiography and gated SPECT was observed for both baseline (p = 0.78) and LDD (p = 0.74) WM score index. CONCLUSIONS: In patients with coronary artery disease who have LV dysfunction, nitrate-enhanced sestamibi gated SPECT allows a reliable WM evaluation, both at rest and during LDD infusion, in almost all segments and provides results in agreement with LDDE.

Adult↗
PubMedDate not supplied

Two- and three-dimensional assessments of myocardial perfusion and function by using technetium-99m sestamibi gated SPECT with a combination of count- and image-based techniques.

BACKGROUND: Although the myocardial gated single photon emission computed tomography (SPECT) technique makes it possible to assess concurrent myocardial perfusion and function, quantitative methods for analyzing and displaying gated SPECT data in 2- and 3-dimensional presentations for regional and global cardiac assessment have not been established. METHODS AND RESULTS: We have developed an automated quantitative method for assessing perfusion and function by means of technetium-99m sestamibi gated SPECT with a computerized technique combining count-based and image-based methods. We have examined its validity in 91 patients by comparing its results with those of conventional techniques: contrast left ventriculography and radionuclide angiocardiography. In addition to color-scale displays of regional function, simultaneous 3-dimensional presentations of regional wall motion and perfusion have been produced. High reproducibility of gated SPECT analysis with this algorithm was demonstrated; interoperator errors (%CV) were 2.6% to 5.5%, and good intraobserver reproducibility was confirmed by means of high correlation coefficients (0.954 to 0.989). Left ventricular volumes assessed by means of contrast left ventriculography and by means of the gated SPECT technique showed significant correlations (left ventricular end-diastolic volume, y = 1.01x - 9.7, r = 0.845, P<.001, standard errors of the estimate [SEE] = 14 mL; left ventricular end-systolic volume, y = 1.03x - 1.4, r = 0.902, P<.001, SEE = 6 mL). Left ventricular ejection fraction determined by means of gated SPECT with the new algorithm closely correlated with that determined by means of radionuclide ventriculography (y = 1.05x - 0.6, r = 0.891, P<.001, SEE = 3 %). These parameters quantified by means of the present method correlated closely with those derived from the QGS program (r = 0.926 to 0.987). CONCLUSION: In comparison with conventional techniques, myocardial gated SPECT with automated quantitative analysis provides accurate and reproducible data for global and regional function. Quantitative concurrent assessment of myocardial perfusion and function by using 2-and 3-dimensional representations appears to be superior to other modalities and to contribute to nuclear cardiology practice.

Adult↗
PubMedDate not supplied

Artifactual reverse distribution pattern in myocardial perfusion SPECT with technetium-99m sestamibi.

BACKGROUND: The reverse distribution pattern (RDP), in which resting perfusion imaging demonstrates a de novo or more marked regional defect than that present in stress images, is observed frequently in patients with a low likelihood of coronary artery disease. METHODS AND RESULTS: To determine whether this scan pattern is artifactual and to investigate its causes, we retrospectively evaluated scans in 202 patients with a low likelihood of coronary artery disease (77 men and 125 women) undergoing single-day rest/stress technetium-99m sestamibi single photon emission computed tomography (SPECT). The presence and location of RDP was correlated with relevant body habitus parameters. RDP was observed in 15.3% of patients. The finding was significantly more frequent in patients who were obese (P<.02 in men, P<.03 in women), in men with abdominal protuberance (P<.05), and in women with prominent breast "shadows" observed on planar projection images (P<.008). RDP was most frequent in the right coronary artery territory in men and the left anterior descending coronary artery territory in women. It was demonstrated by means of a cardiac SPECT phantom experiment that soft tissue attenuation effects were most evident in low count density SPECT studies with localized soft tissue attenuation, accounting for the higher than clinical observation of RDP in obese patients undergoing low-dose rest/high-dose imaging. CONCLUSIONS: RDP is a frequently encountered artifact in obese patients undergoing rest/stress Tc-99m sestamibi SPECT, particularly in men with abdominal protuberance and in women with large, dense breasts.

Artifacts↗
PubMedDate not supplied

Low-dose dobutamine nitrate-enhanced technetium 99m sestamibi gated SPECT versus low-dose dobutamine echocardiography for detecting reversible dysfunction in ischemic cardiomyopathy.

BACKGROUND: The simultaneous assessment of perfusion and function with the use of technetium 99m sestamibi gated single photon emission computed tomography (SPECT) is helpful for the detection of myocardial viability, but its value in comparison with more established methods is not yet defined. METHODS AND RESULTS: This study compared low-dose dobutamine (LDD) nitrate-enhanced gated SPECT with LDD echocardiography for predicting recovery of regional ventricular function after revascularization in 25 patients with ischemic cardiomyopathy. In both studies, regional function (wall motion and thickening) at rest, during inotropic stimulation, and after revascularization was scored by a 4-point scale. In LDD echocardiography, the prediction of reversible dysfunction was based on the recognition of contractile reserve in asynergic (hypokinetic or a-dyskinetic) segments. In LDD gated sestamibi SPECT, reversible dysfunction was predicted on the basis of perfusion quantification (sestamibi uptake >or= 50%) in a-dyskinetic segments and on the basis of contractile reserve in hypokinetic segments. LDD echocardiography predicted reversible dysfunction with sensitivity, specificity, and global accuracy of 57%, 85%, and 75%, respectively. The sensitivity and specificity of LDD gated SPECT for identifying dysfunctional segments capable of functional recovery were 77% and 88%, respectively, with a diagnostic accuracy of 84% (P <.02 vs LDD echocardiography). CONCLUSIONS: The combined use of 2 different markers of viability, such as cellular integrity in a-dyskinetic segments and contractile reserve in hypokinetic segments, as permitted by LDD gated sestamibi SPECT, showed higher predictive accuracy for reversible dysfunction than the assessment of contractile reserve in all asynergic segments with LDD echocardiography.

Aged↗
PubMed2001

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.

Cryopreservation↗
PubMed2002

Prospective evaluation of delayed technetium-99m sestamibi SPECT scintigraphy for preoperative localization of primary hyperparathyroidism.

BACKGROUND: Delayed technetium-99m sestamibi single photon emission computed tomography (SPECT) scans were prospectively analyzed in a large series of patients with primary hyperparathyroidism. METHODS: Three hundred thirty-eight patients underwent sestamibi-SPECT and were explored. Prospective data included preoperative demographics, clinical, sestamibi, and operative findings, laboratory values, and pathologic and follow-up laboratory results from all patients. RESULTS: Between 1994 and 2000, 287 unexplored patients (85%) and 51 re-explored patients (15%) participated. The abnormal parathyroid glands excised from 336 of 338 patients included 299 single adenomas (88%) and 23 double adenomas (7%), and 14 patients had multigland hyperplasia (4%). Sestamibi SPECT correctly lateralized 349 of 400 abnormal parathyroid glands, with an overall sensitivity of 87%, an accuracy of 94%, and a positive predictive value of 86%. Precise localization occurred in 82% of the abnormal parathyroid glands. Sestamibi sensitivity was similar in unexplored (87%) and reoperative (92%) cases; two hundred eighty-six of 299 (96%) solitary adenomas, 38 of 46 (83%) double adenomas, but only 25 of 55 (45%) hyperplastic glands were identified. The mean weight of the true-positive glands (1252 +/- 1980 mg) was greater than that of the false-negative glands (297 +/- 286 mg) (P <.005). Three patients had persistent primary hyperparathyroidism, in spite of the excision of sestamibi-identified lesions in 2 cases. Follow-up indicated curative resection in 99% of the unexplored cases and 94% of the remedial cases. CONCLUSIONS: Sestamibi SPECT is highly accurate for the localization of parathyroid adenomas in unexplored and re-explored cases, where it is often the only imaging required. Its sensitivity is limited in multiglandular disease.

Adenoma↗
PubMed2002

Improving the yield of preoperative parathyroid localization: technetium Tc 99m-sestamibi imaging after thyroid suppression.

BACKGROUND: Preoperative localization is essential for successful directed, minimally invasive or reoperative parathyroidectomy. Standard technetium Tc 99m-sestamibi imaging is the most sensitive modality for localization. We reviewed our experience with (99m)Tc-sestamibi imaging and specifically investigated the effect of thyroid suppression on repeat imaging of patients who had initially nonlocalizing scans. METHODS: . The records of patients who underwent (99m)Tc-sestamibi imaging during evaluation for primary hyperparathyroidism were reviewed. A subset of patients with initially nonlocalizing scans underwent thyroid suppression with either thyroxin or liothyronine and then had their scans repeated. RESULTS: Ninety-nine patients with primary hyperparathyroidism underwent (99m)Tc-sestamibi imaging followed by parathyroidectomy (initial operation, 78; reoperation, 21). Successful parathyroid localization was obtained on standard imaging in 67 patients. Fourteen of 32 patients who had nonlocalizing (99m)Tc-sestamibi imaging studies underwent an additional scan after thyroid suppression. In 10 of 14 patients (71%), repeat (99m)Tc-sestamibi imaging after thyroid suppression successfully localized abnormal parathyroid tissue. CONCLUSIONS: Thyroid suppression may improve the yield of (99m)Tc-sestamibi imaging in patients with hyperparathyroidism who have an initially nonlocalizing study. This diagnostic strategy may be helpful in patients motivated to undergo a directed, minimally invasive operation, as well as in the evaluation of patients for reoperative parathyroidectomy.

Humans↗
PubMed2002

Use of technetium-99m tin colloid for sentinel lymph node identification in non-small cell lung cancer.

BACKGROUND: To test the reliability of sentinel lymph node identification in non-small cell lung cancer, sentinel nodes were localized with a radioactive colloid in patients undergoing surgery. METHODS: Forty-six patients with non-small cell lung cancer undergoing curative resection with mediastinal lymph node dissection were examined. The day before surgery, technetium-99m ((99m)Tc) tin colloid was injected into the peritumoral region. At operation, the radioactivity of the lymph nodes was counted with a handheld gamma counter before (in vivo) and after (ex vivo) dissection. Lymph nodes with an ex vivo radioactive count more than 10 times the background value were identified as sentinel nodes. The correlation between the in vivo and ex vivo results was examined. RESULTS: Lymphoscintigraphy revealed that it took longer than 6 hours for sufficient (99m)Tc tin colloid to reach the sentinel nodes. Sentinel nodes could be identified in 40 patients (87%). Patients whose sentinel nodes could not be identified had a significantly lower ratio of forced expiratory volume in 1 second to forced vital capacity than did those with identifiable sentinel nodes (P =.03). No false-negative sentinel nodes were detected in 14 patients with N1 or N2 disease (0%). In the hilar lymph node stations, the lobar lymph nodes were most frequently identified as sentinel nodes (as often as 85% of the time). Fourteen patients (35%) had sentinel nodes in the mediastinum, the distribution of which depended on the lobe. In vivo and ex vivo counting showed 88% concurrence for the identification of sentinel nodes in mediastinal lymph node stations. CONCLUSION: The identification of sentinel nodes with (99m)Tc tin colloid is a reliable method of establishing the first site of nodal metastasis in non- small cell lung cancer. Sentinel nodes could be hardly identified in patients with a low ratio of forced expiratory volume in 1 second to forced vital capacity because of such conditions as chronic obstructive pulmonary disease. In vivo identification of sentinel nodes in the mediastinum could be useful approach to guide mediastinal lymph node sampling or dissection.

Adult↗