Sestamibi Single-photon Emission Computed Tomography Research Articles

Myocardial perfusion imaging using technetium-99m sestamibi in asymptomatic diabetic patients

Myocardial perfusion single-photon emission computed tomography (SPECT) has been extensively applied in the clinical assessment of patients with diabetes mellitus. The aim of the present study was to evaluate stress technetium-99m sestamibi SPECT MPI perfusion in silent myocardial ischemia and its association with some clinical and laboratory parameters in an asymptomatic diabetic population. 83 subjects (age: 57.1±6.9 years) with at least five years history of type 2 diabetes, and no suspected or documented coronary artery disease (CAD) accomplished myocardial perfusion imaging; angiography was also performed in patients with abnormal MPI. MPI results showed that 58 patients had normal myocardial perfusion, while 25 patients showed perfusion defects (23 reversible and 2 fixed) on MPI. 12 out of the 25 (48%) with abnormal MPI findings represented abnormal angiography. We observed that pretest likelihood of CAD (odds ratio 2.32; 95%-CI: 1.05-5.13; p = 0.038) and higher HbA1c level (odds ratio 1.70; 95%-CI, 1.07-2.71; p = 0.02) were independently associated with abnormal MPI. Occult CAD was present on MPI in 1/3 patients with DM without abnormal electrocardiographic findings or evidence of peripheral arterial disease.

Granulocyte colony‐stimulating factor attenuates left ventricular remodelling after acute anterior STEMI: results of the single‐blind, randomized, placebo‐controlled multicentre STem cEll Mobilization in Acute Myocardial Infarction (STEM‐AMI) Trial

The aim of this study was to assess the effect of granulocyte colony-stimulating factor (G-CSF) on left ventricular (LV) function and volumes in patients with anterior ST-elevation myocardial infarction (STEMI) and depressed LV ejection fraction (EF). Sixty consecutive patients with anterior STEMI, undergoing primary angioplasty percutaneous coronary intervention (PCI), with symptom-to-reperfusion time of 2-12 h and EF ≤45% after PCI, were randomized to G-CSF 5 μg/kg b.i.d. subcutaneously (n = 24) or placebo (n = 25) for 5 days, starting <12 h after PCI. The primary endpoint was an increase from baseline to 6 months of 5% in left ventricular ejection fraction (LVEF), as measured by magnetic resonance imaging (MRI). Co-primary endpoint was a ≥20 mL difference in end-diastolic volume (EDV). Infarct size and perfusion were evaluated with late gadolinium enhancement (LGE) and gated (99m)Technetium Sestamibi single-photon emission computed tomography (SPECT). Left ventricular EDV and end-systolic volume (ESV) increased from baseline to 6 months in the placebo group (81.7 ± 24.4 to 94.4 ± 26.0 mL/m(2), P < 0.00005 and 45.2 ± 20.0 to 53.2 ± 23.8 mL/m(2), P = 0.016) but were unchanged in the G-CSF group (82.2 ± 20.3 to 85.7 ± 23.7 mL/m(2), P = 0.40 and 46.0 ± 18.2 to 48.4 ± 20.8 mL/m(2), P = 0.338). There were no significant differences in EF or perfusion between groups. A significant reduction in transmural LGE segments was seen at 6 months in the G-CSF vs. placebo groups (4.38 ± 2.9 to 3.3 ± 2.6, P = 0.04 and 4.2 ± 2.6 to 3.6 ± 2.7, P = 0.301, respectively). Significantly more placebo patients had a change in left ventricular end-diastolic volume abovethe median (9.3 mL/m(2)) when reperfusion time exceeded 180 min (median time-to-reperfusion) (P = 0.0123). Severe adverse events were similar between groups. Early G-CSF administration attenuates ventricular remodelling in patients with anterior STEMI and EF ≤45% after successful PCI.

Peak Cardiac Troponin-T Level, Scintigraphic Myocardial Infarct Size and One-Year Prognosis in Patients Undergoing Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction

Current guidelines recommend troponin T (TnT) as the biomarker of choice in the diagnosis of myocardial infarction. In patients with ST-elevation myocardial infarction (STEMI) however, its role in providing a measurement of infarct size and its association with survival is less well established. We sought to assess the correlation of TnT and creatine kinase-MB (CK-MB) with scintigraphically determined infarct size and to assess the predictive value of all 3 parameters on 12-month mortality. Patients presenting with STEMI managed with primary percutaneous intervention underwent serial TnT and CK-MB measurements at admission and for ≥72 hours after presentation. Before hospital discharge patients underwent assessment of infarct size by technetium-99m sestamibi single-photon emission computed tomographic (SPECT) scan. Clinical follow-up was performed up to 1 year. Data were available for 1,237 patients. Mean age was 62.9 ± 12.9 years. Infarct location was anterior in 509 patients (41%); 75 (6.1%) had cardiogenic shock. Median admission and peak TnT were 0.74 μg/L (0.10 to 2.70) and 3.70 μg/L (1.69 to 6.99), respectively. Corresponding values for CK-MB were 44.1 U/L (21.0 to 108.8) and 160.0 U/L (69.0 to 301.0), respectively. Median infarct size on SPECT scan was 12.0% (3.0 to 25.0) of the left ventricle. Peak TnT and CK-MB demonstrated similar moderate correlation with final infarct size (r = 0.45, p <0.001, and r = 0.41, p <0.001 respectively). This correlation was not affected by Thrombolysis In Myocardial Infarction flow grade after intervention. At 1 year, 47 patients (3.8%) had died. Final infarct size at SPECT scanning better predicted mortality than peak TnT or CK-MB. In conclusion, this study is the largest investigation on the value of cardiac troponin for assessment of infarct size in acute STEMI. Compared to peak CK-MB, peak TnT shows similar correlation with scintigraphic infarct size, although scintigraphic infarct size remains a better correlate of 1-year mortality than either biomarker.

The Timing and Impact of Follow-Up Studies After Normal Stress Single-Photon Emission Computed Tomography Sestamibi Studies

Background— The purpose of this study was to determine the prevalence and timing of routine follow-up single-photon emission computed tomography (SPECT) studies after a normal stress SPECT scan compared with the patient's warranty period (ie, time to 1% risk of death or myocardial infarction). Methods and Results— We identified patients at Mayo Clinic Rochester who had normal stress SPECT scans in 2002. Of 2354 patients without prior coronary artery disease, 309 (13%) had routine follow-up scans. The time to routine follow-up was a median of 2.1 years (25th percentile, 1.2 years; 75th percentile, 3.6 years). This interval was a median of 45% of the warranty period. Of the 309 patients, only 9 (3%) underwent subsequent coronary angiography, without revascularization. Of 656 patients with prior coronary artery disease, 171 (26%) had routine follow-up scans. The time to routine follow-up was a median of 1.6 years (25th percentile, 1.0 years; 75th percentile, 2.7 years). This interval was a median of 164% of the warranty period. Of the 171 patients, only 7 (4%) underwent coronary angiography, without revascularization. Conclusions— In patients without prior coronary artery disease, routine follow-up SPECT scans are performed infrequently but well before the end of the patient's warranty period. Routine follow-up scans are performed more commonly in patients with prior coronary artery disease but generally after the end of the warranty period. Routine follow-up SPECT scans have minimal impact on referral to catheterization or revascularization.

Silent ischemia in relation to insulin resistance in normotensive prediabetic adults: early detection by single photon emission computed tomography (SPECT)

Myocardial perfusion imaging (MPI) is a powerful diagnostic and prognostic tool for evaluating coronary artery disease (CAD). Several studies have shown that it is increased in individuals with type 2 diabetes. Also, insulin resistance is generally considered to be of major importance in the pathophysiology of type 2 diabetes mellitus. However the area of screening prediabetics for coronary artery disease remains unclear. Given that glucose intolerance and insulin resistance precede the development of overt diabetes, these factors would be associated with ischemic heart disease. Evaluate the state of myocardial perfusion in prediabetic adults detected by Single photon emission computed tomography (SPECT) in relation to insulin resistance. A descriptive study was performed. For 163 consecutive prediabetic adults of whom 62 had insulin resistance (group A) and 101 had insulin sensitivity (group B). All were subjected to full medical history and clinical examination including blood pressure, waist circumference body mass index. Biochemical studies including lipids profile, fasting glucose and HOMA test. Exercise treadmill technetium 99 sestamibi SPECT scintigraphy were done for assessment of myocardial perfusion assessed by summed difference score as well as occurrence of transient left ventricular dilatation. Significant increase in summed difference score as well as transient left ventricular dilatation were observed in group A than group B. It is correlated with insulin resistance and the correlation appears to be independent of glucose tolerance status and obesity. Similar correlations were observed with age, triglycerides and waist circumference. Prediabetics have myocardial perfusion defects which represent a pattern of cardiovascular risk factors. These changes are predominantly observed in these prediabetics with increased HOMA IR and visceral obesity independent of glucose levels.

Silent myocardial ischemia in prediabetics in relation to insulin resistance

Background:Myocardial perfusion imaging (MPI) is a powerful diagnostic and prognostic tool for evaluating coronary artery disease (CAD). Several studies have shown Type 2 diabetics are at increased risk for having CAD. In addition, insulin resistance is generally considered to be of major importance in the pathophysiology of Type 2 diabetes mellitus. However, the area of screening prediabetics for CAD remains unclear. Given that glucose intolerance and insulin resistance precede the development of overt diabetes, these factors would be associated with CAD.Aim:This study was designed to evaluate the state of myocardial perfusion in prediabetic adults detected by single photon emission computed tomography (SPECT) in relation to insulin resistance.Patients and Methods:A descriptive study was performed. Out of 113 consecutive prediabetic adults, 32 had insulin resistance (Group A) and 81 had insulin sensitivity (Group B). All were subjected to full medical history and clinical examination including blood pressure, waist circumference, and body mass index. Biochemical studies including lipids profile, fasting blood glucose, and homeostasis model assessments (HOMA) test. Exercise treadmill technetium (99mTC) sestamibi SPECT scintigraphy were done for assessment of myocardial perfusion assessed by summed difference score as well as occurrence of transient left ventricular dilatation.Results:Significant increase in summed difference score as well as transient left ventricular dilatation was observed in Group A than Group B. It is correlated with insulin resistance, and the correlation appears to be independent of glucose tolerance status and obesity. Similar correlations were observed with age, triglycerides, and waist circumference.Conclusion:Prediabetics have myocardial perfusion defects which represent a pattern of cardiovascular risk. These are predominantly observed in prediabetics with increased HOMA IR and visceral obesity independent of glucose levels.

Recognition of Image Artifacts on Myocardial Perfusion SPECT Enhanced by Iterative Reconstruction

Abstract: Iterative reconstruction, such as ordered subsets expectation maximization (OSEM), incorporated with resolution recovery has been routinely used to improve image resolution in myocardial perfusion single photon emission computed tomography (SPECT). Compared with traditional filtered back-projection (FBP), this type of reconstruction may also adversely enhance image artifacts from soft-tissue attenuation or by scatter of extracardial activities. We demonstrate these findings from 2 patients who underwent Tc-99m sestamibi (MIBI) SPECT. In one patient, subdiaphragmatic attenuation artifact in FBP images was worsened with OSEM. In the other patient, a hot spot presented in FBP images was enhanced to decrease the image intensity in other myocardial segments due to adjacent hot bowel.

Diagnostic accuracy of contrast echocardiography during adenosine stress for detection of abnormal myocardial perfusion: a prospective comparison with technetium-99 m sestamibi single-photon emission computed tomography

Myocardial contrast echocardiography (MCE) utilizes compressible microbubbles behaving similarly to red blood cells. Destruction of microbubbles and observation of the gradual refill into the myocardium are key to evaluating perfusion using real-time MCE. We aimed to assess the feasibility and diagnostic accuracy of qualitative MCE utilizing a 17-segment model for localization of myocardial perfusion abnormalities compared with simultaneous technetium-99 m sestamibi single-photon emission computed tomography (SPECT). From July 2005 through August 2007, 97 patients with known or suspected coronary artery disease underwent simultaneous SPECT and realtime MCE during adenosine stress. Qualitative MCE and tracer uptake were analyzed visually using a 17-segment model in a blinded manner. Diagnostic accuracy and 95% confidence interval (CI) were determined. Myocardial contrast echocardiography was completed in 91 patients (age, mean [SD], 69.3 [10.9] years; body mass index, 30.0 [6.3]; 59 males [65%]). Myocardial contrast echocardiography analysis was feasible in 88 (97%) patients (261 of 264 [99%] territories; 1299 of 1497 [87%] segments). At patient level, MCE sensitivity was 88% (95% CI, 79%-94%); specificity was 85% (77%-90%). For disease detection in individual coronary territories, sensitivity and specificity were 84% (71%-92%) and 79% (72%-84%) for the left anterior descending artery; 62% (38%-80%) and 88% (83%-91%) for the left circumflex artery; and 73% (57%-82%) and 94% (89%-97%) for the right coronary artery. For MCE combined with wall-motion analysis, concordance with SPECT improved from 80% to 86%. Myocardial contrast echocardiography interobserver concordance was 81% (kappa [SE], 0.611 [0.78]). Myocardial contrast echocardiography accuracy was comparable in patients classified in accordance with presence of diabetes mellitus, myocardial infarction, hypertension, or percutaneous coronary intervention. Improved MCE specificity in detecting perfusion defects was seen in patients with no history of coronary bypass graft surgery (P = 0.005). Real-time MCE with a 17-segment model for analysis has good feasibility and accuracy in evaluation of myocardial perfusion during adenosine stress.

Temporal trends in compliance with appropriateness criteria for stress single-photon emission computed tomography sestamibi studies in an academic medical center

The purpose of this study was to apply published appropriateness criteria for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a single academic medical center to determine if the percentage of inappropriate studies was changing over time. In a previous study, we applied the American College of Cardiology Foundation/American Society of Nuclear Cardiology (ASNC) appropriateness criteria for stress SPECT MPI and reported that 14% of stress SPECT studies were performed for inappropriate reasons. Using similar methodology, we retrospectively examined 284 patients who underwent stress SPECT MPI in October 2006 and compared the findings to the previous cohort of 284 patients who underwent stress SPECT MPI in May 2005. The indications for testing in the 2 cohorts were very similar. The overall level of agreement in characterizing categories of appropriateness between 2 experienced cardiovascular nurse abstractors was good (kappa = 0.68), which represented an improvement from our previous study (kappa = 0.56). There was a significant change between May 2005 and October 2006 in the overall classification of categories for appropriateness (P = .024 by chi(2) statistic). There were modest, but insignificant, increases in the number of patients who were unclassified (15% in the current study vs 11% previously), appropriate (66% vs 64%), and uncertain (12% vs 11%). Only 7% of the studies in the current study were inappropriate, which represented a significant (P = .004) decrease from the 14% reported in the 2005 cohort. In the absence of any specific intervention, there was a significant change in the overall classification of SPECT appropriateness in an academic medical center over 17 months. The only significant difference in individual categories was a decrease in inappropriate studies. Additional measurements over time will be required to determine if this trend is sustainable or generalizable.

Localization of Parathyroid Adenomas by Sonography and Technetium Tc 99m Sestamibi Single-Photon Emission Computed Tomography Before Minimally Invasive Parathyroidectomy: Are Both Studies Needed?

Localization of Parathyroid Adenomas by Sonography and Technetium Tc 99m Sestamibi Single-Photon Emission Computed Tomography Before Minimally Invasive Parathyroidectomy: Are Both Studies Needed?

Absolute myocardial blood flow determination using real-time myocardial contrast echocardiography during adenosine stress: comparison with single-photon emission computed tomography

Objective:To assess the feasibility and diagnostic accuracy of real-time myocardial contrast echocardiography (MCE)-derived absolute myocardial blood flow for detection of myocardial perfusion abnormalities compared with simultaneous technetium 99 m sestamibi...

Detection of myocardial infarction by dual-source coronary computed tomography angiography using quantitated myocardial scintigraphy as the reference standard

Background:Dual-source coronary computed tomography angiography (DS-CTA) has the potential to assess both coronary anatomy and myocardial perfusion. We studied the ability of DS-CTA to detect myocardial infarction (MI) compared to...

Localization of Parathyroid Adenomas by Sonography and Technetium Tc 99m Sestamibi Single-Photon Emission Computed Tomography Before Minimally Invasive Parathyroidectomy

The purpose of this study was to determine the utility of radiologist-performed sonography as the principal modality for parathyroid localization before minimally invasive parathyroidectomy. Both sonography and technetium Tc 99m sestamibi single-photon emission computed tomography (SPECT) are commonly performed during imaging evaluation of patients with primary hyperparathyroidism (HPTH). Sonographic examinations ordered during the study period were performed by 1 author (M.E.T.), and results were immediately reported. Findings of a subsequent Tc 99m sestamibi study were recorded blinded to the sonographic results. The sensitivity and specificity of sonography and Tc 99m sestamibi SPECT were assessed with the use of surgery and pathology reports as a reference standard. The 2007 global Medicare reimbursement rates were used to assess the costs of preoperative localization. Parathyroidectomy was performed in 144 of 172 patients evaluated by both modalities. The sensitivity, specificity, and positive predictive value of sonography for identifying abnormal parathyroid glands were 74%, 96%, and 90%, respectively. Sonography correctly localized a single adenoma or suggested multiglandular disease in 112 of 144 patients (78%). The sensitivity, specificity, and positive predictive value of SPECT were 58%, 96%, and 89%. Technetium 99m sestamibi SPECT correctly predicted an adenoma or multiglandular disease in 88 of 144 patients (61%). Five patients with negative sonographic findings were shown to have uniglandular disease on Tc 99m sestamibi SPECT. Selective use of Tc 99m sestamibi SPECT (ie, when sonographic findings were negative or equivocal) would have decreased the cost of imaging by 53%. Radiologist-performed sonography may potentially be used as a principal imaging modality for patients with HPTH. Selective use of Tc 99m sestamibi in cases with negative or equivocal sonographic findings can decrease the cost of imaging before parathyroid resection considerably.

Incremental prognostic value of cardiac single-photon emission computed tomography after nitrate administration in patients with ischemic left ventricular dysfunction

BackgroundWe evaluated the incremental prognostic value of viability assessment by nitrate single-photon emission computed tomography (SPECT) in patients with ischemic left ventricular (LV) dysfunction. Methods and ResultsOne hundred and sixty-four patients with previous myocardial infarction and LV dysfunction (ejection fraction 29% ± 15%) underwent two Tc-99m sestamibi SPECT studies, under control conditions and after sublingual nitrate administration, for evaluation of myocardial viability. In each patient, viability was defined as the presence of ≥2 severely dysfunctional segments with preserved tracer uptake (≥55% of peak activity). Cardiac death, myocardial infarction, and late (>2 months) revascularization were considered events. Follow-up was 98% complete at a mean period of 30 ± 24 months. At baseline SPECT, 119 (73%) patients had evidence of viable myocardium, while 45 (27%) did not. Of these latter patients, 18 (40%) had evidence of viability after nitrate administration. Cardiac events occurred in 58 (35%) patients. Cumulative probability of event-free survival was similar in patients with and without viability at baseline SPECT (log rank 0.3, P = NS), while it was lower in patients with viability at nitrate SPECT compared to those without (log rank 6.3, P < .01). The addition of nitrate SPECT data significantly improved the prognostic power of the model including clinical, functional, angiographic, and baseline SPECT data (P < .01). ConclusionsIn patients with previous myocardial infarction and LV dysfunction, nitrate SPECT imaging provides incremental prognostic information over those obtained from clinical, functional, angiographic variables, and baseline SPECT data.

Prevalence and predictors of an abnormal stress myocardial perfusion study in asymptomatic patients with type 2 diabetes mellitus

The purpose of this study was to evaluate the prevalence of an abnormal stress myocardial perfusion study in a cohort of truly asymptomatic patients with type 2 diabetes mellitus using myocardial perfusion imaging by means of single photon emission computed tomography (SPECT). Secondly, we determined which clinical characteristics may predict an abnormal stress myocardial perfusion study in this population. A total of 120 asymptomatic patients (mean age 53+/-10 years) with type 2 diabetes mellitus and one or more risk factors for coronary artery disease were prospectively recruited from an outpatient diabetes clinic. All patients underwent myocardial perfusion imaging by means of adenosine (99m)Tc sestamibi SPECT. Images were evaluated for the presence of perfusion abnormalities as well as other nonperfusion abnormalities that may indicate extensive ischaemia, including left ventricular dysfunction (defined as a left ventricular ejection fraction <45%), transient ischaemic dilatation and adenosine-induced ST segment depression. Multivariable analysis was performed using a backward selection strategy to identify potential predictors for an abnormal stress myocardial perfusion study. Finally, all patients were followed up for 12 months to determine the occurrence of cardiovascular events: (1) cardiac death, (2) nonfatal myocardial infarction, (3) unstable angina requiring hospitalization, (4) revascularization, or (5) stroke. Of the 120 patients, 40 (33%) had an abnormal stress study, including myocardial perfusion abnormalities in 30 patients (25%). In 10 patients (8%), indicators of extensive (possibly balanced ischaemia) were observed in the absence of abnormal perfusion. The multivariable analysis identified current smoking, duration of diabetes and the cholesterol/high-density lipoprotein (HDL) ratio as independent predictors of an abnormal stress study. During a follow-up period of 12 months six patients (5%) had a cardiovascular event. The current study revealed a high prevalence of abnormal stress myocardial perfusion studies in patients with type 2 diabetes mellitus despite the absence of symptoms. In contrast to earlier studies, current smoking, duration of diabetes and the cholesterol/HDL ratio were identified as independent predictors of an abnormal study.

Parathyroid Scintigraphy in Patients with Primary Hyperparathyroidism:99mTc Sestamibi SPECT and SPECT/CT

The clinical diagnosis of primary hyperparathyroidism is based largely on serum laboratory test results, as patients often are asymptomatic. Surgery, often with bilateral exploration of the neck, has been considered the definitive treatment for symptomatic disease. However, given that approximately 90% of cases are due to a single parathyroid adenoma, a better treatment may be the selective surgical excision of the hyperfunctioning parathyroid gland after its preoperative identification and localization at radiologic imaging. Scintigraphy and ultrasonography are the imaging modalities most often used for preoperative localization. Various scintigraphic protocols may be used in the clinical setting: Single-phase dual-isotope subtraction imaging, dual-phase single-isotope imaging, or a combination of the two may be used to obtain planar or tomographic views. Single photon emission computed tomography (SPECT) with the use of technetium-99m ((99m)Tc) sestamibi as the radiotracer, especially when combined with x-ray-based computed tomography (CT), is particularly helpful for preoperative localization: The three-dimensional functional information from SPECT is fused with the anatomic information obtained from CT. In addition, knowledge of the anatomy and embryologic development of the parathyroid glands and the pathophysiology of primary hyperparathyroidism aid in the identification and localization of hyperfunctioning glands.

Direct comparison between pharmacological stress with adenosine triphosphate disodium and exercise stress myocardial perfusion imagings

To clarify the significance of adenosine triphosphate disodium stress myocardial perfusion imaging (ATP-MPI), we directly compared the findings of ATP-MPI with those of exercise stress myocardial perfusion imaging (Ex-MPI). ATP-MPI, Ex-MPI, and coronary angiography (CAG) were performed within 60 days in 17 coronary artery disease patients with mean age of 62.1+/-7.9 years. CAG revealed single-vessel disease (SVD) in 10 patients and multivessel disease (MVD) in seven patients. The summed stress score (SSS) of ATP-MPI was significantly higher than that of Ex-MPI (10.0 [7.8-14.3] vs. 8.0 [4-18], P<0.05). No difference in the SSS was observed between ATP-MPI and Ex-MPI in patients with SVD (8.0 [6.0-9.0] vs. 8.0 [6.0-10.0], NS), whereas this difference was significant in patients with MVD (15.0 [14.0-22.8] vs.9 [7.3-16.3], P<0.05). There was no difference in the summed rest score between ATP-MPI and Ex-MPI. The univariate logistic analysis showed that "MVD" was the significant factor influencing to the overt discrepancy between ATP-MPI and Ex-MPI (odds ratio: 9.0, 95% confidence interval: 1.07-75.84, P=0.043). The accuracy of ATP-MPI and Ex-MPI in detecting the territory of stenotic coronary vessel or previous myocardial infarction was 98.0% and 92.1% (NS), respectively. In conclusion, ATP-MPI is useful for detecting potential ischemic areas that cannot be detected by Ex-MPI, particularly in patients with MVD.

Preoperative Parathyroid Scintigraphic Lesion Localization: Accuracy of Various Types of Readings

To retrospectively compare the accuracy of various parathyroid scintigraphy readings for single-gland disease (SGD) and multigland disease (MGD) in patients with primary hyperparathyroidism, with histologic analysis as the reference standard. Institutional review board approval was obtained for this HIPAA-compliant study. Records of 462 patients with primary hyperparathyroidism who underwent preoperative imaging with a technetium 99m ((99m)Tc) sestamibi and (99m)TcO4- protocol that consisted of early and late pinhole (99m)Tc sestamibi, pinhole thyroid imaging, image subtraction, and single photon emission computed tomography (SPECT) were retrospectively reviewed. An experienced nuclear medicine physician without knowledge of other test results or of the final diagnoses graded images on a scale from 0 (definitely normal) to 4 (definitely abnormal). Early pinhole (99m)Tc sestamibi images, late pinhole (99m)Tc sestamibi images, subtraction images, SPECT images, early and late pinhole (99m)Tc sestamibi images, all planar images, and all images--including SPECT images--were read in seven sessions. Receiver operating characteristic curves were generated for each session and were used to calculate sensitivity, specificity, and accuracy. A total of 534 parathyroid lesions were excised. Of the 462 patients, 409 had one lesion, whereas 53 had multiple lesions. Reading all images together was more accurate (89%, P = .001) than was reading early (79%), late (85%), subtraction (86%), and SPECT (83%) images separately; however, it was not significantly more accurate than reading planar images (88%) or early and late images together (87%). Reading all images was significantly less sensitive in the detection of lesions with a median weight of 600 mg or less than in the detection of lesions with a median weight of more than 600 mg (86% vs 94%, P = .004). Per-lesion sensitivity for reading all images was significantly higher for SGD than for MGD (90% vs 66%, P < .001). Sensitivity of reading all images together in the identification of patients with MGD was 62%. Reviewing early, late, and subtraction pinhole images together with SPECT images maximizes parathyroid lesion detection accuracy. Test sensitivity is adversely affected by decreasing lesion weight and MGD.

Efficacy of 4D-CT Preoperative Localization in 2 Patients with MEN 2A

Multiple endocrine neoplasia type 2A (MEN2A) is an autosomal dominant syndrome that is associated with hyperparathyroidism in 20% to 30% of adult gene carriers. The appropriate surgical management of these patients remains in question. Approaches to this disease range from selective gland resection to a subtotal parathyroidectomy with or without autotransplantation. Despite surgical intervention, disease recurrence is problematic. Surgical management of patients found to have recurrence relies on localizing the anatomic location of the hyperfunctional gland(s). The primary imaging modality for localization of hyperfunctioning parathyroid glands is technetium 99m sestamibi single photon emission computed tomography (SPECT). Although sestamibi imaging has a sensitivity of 60% to 90%, specific anatomic detail is not always present by this imaging modality. Four-dimensional computed tomography (4D-CT) scans allow localization of ectopic parathyroid glands and autotransplanted parathyroid tissue, and they provide the anatomic detail necessary for decisions about appropriate surgical management. Another benefit of the 4D-CT scan is that enhancement characteristics, which are determined by contrast opacification of the hyperfunctional parathyroid tissue over 4 phases of the scan, correlate with metabolic activity. We recommend the use of 4D-CT scanning because of its capacity to identify hyperfunctional parathyroid glands and to provide anatomic information important in preoperative planning.

Differential effects comparing exercise and pharmacologic stress on left ventricular function using gated Tc-99m sestamibi SPECT

Although post-ischemic stunning has emerged as an important marker for severe coronary artery disease (CAD), differences in stress methods may have different effects on left ventricular (LV) volumes and function. To assess differential effects comparing exercise and pharmacologic stress on the LV measurements, (99m)Tc-sestamibi gated single-photon emission computed tomography (SPECT) acquired more than 30 min after stress and at rest was evaluated in 38 patients undergoing adenosine triphosphate (ATP) stress (ATP group) and 38 age-and sex-matched patients subjected to exercise stress (Ex group) among 268 patients with normal SPECT findings. Coronary risk factors and LV volumetric measurements at baseline were similar in the two groups. Compared with volumetric measurements at rest, end-diastolic volume (EDV) increased (72 +/- 21 ml to 74 +/- 21 ml; P = 0.01), end-systolic volume increased (25 +/- 12 ml to 28 +/- 13 ml; P = 0.001), and ejection fraction (EF) decreased after stress (66% +/- 8% to 63% +/- 9%; P < 0.002) in the ATP group. In the Ex group, by contrast, no such change was observed. In addition, changes in EDV (3 +/- 6 vs. -1 +/- 5 ml; P = 0.01) and the stress-to-rest ratio of EDV (1.04 +/- 0.09 vs. 0.99 +/- 0.08; P < 0.02) after stress were greater in the ATP than in the Ex group. Differential effects of stress methods on LV volumes persist more than 30 min after the stress. These findings should be kept in mind when interpreting post-ischemic stunning.