Sestamibi Single-photon Emission Computed Tomography Research Articles

A cost-utility analysis of 18F-fluorocholine–positron emission tomography imaging for localizing primary hyperparathyroidism in the United States

BackgroundPrimary hyperparathyroidism historically necessitated bilateral neck exploration to remove abnormal parathyroid tissue. Improved localization allows for focused parathyroidectomy with lower complication risks. Recently, positron emission tomography using radiolabeled 18F-fluorocholine demonstrated high accuracy in detecting these lesions, but its cost-effectiveness has not been studied in the United States. MethodsA decision tree modeled patients who underwent parathyroidectomy for primary hyperparathyroidism using single preoperative localization modalities: (1) positron emission tomography using radiolabeled 18F-fluorocholine, (2) 4-dimensional computed tomography, (3) ultrasound, and (4) sestamibi single photon emission computed tomography (SPECT). All patients underwent either focused parathyroidectomy versus bilateral neck exploration, with associated cost ($) and clinical outcomes measured in quality-adjusted life-years gained. Model parameters were informed by literature review and Medicare costs. Incremental cost-utility ratios were calculated in US dollars/quality-adjusted life-years gained, with a willingness-to-pay threshold set at $100,000/quality-adjusted life-year. One-way, 2-way, and threshold sensitivity analyses were performed. ResultsPositron emission tomography using radiolabeled 18F-fluorocholine gained the most quality-adjusted life-years (23.9) and was the costliest ($2,096), with a total treatment cost of $11,245 or $470/quality-adjusted life-year gained. Sestamibi single photon emission computed tomography and ultrasound were dominated strategies. Compared with 4-dimentional computed tomography, the incremental cost-utility ratio for positron emission tomography using radiolabeled 18F-fluorocholine was $91,066/quality-adjusted life-year gained in our base case analysis, which was below the willingness-to-pay threshold. In 1-way sensitivity analysis, the incremental cost-utility ratio was sensitive to test accuracy, positron emission tomography using radiolabeled 18F-fluorocholine price, postoperative complication probabilities, proportion of bilateral neck exploration patients needing overnight hospitalization, and life expectancy. ConclusionOur model elucidates scenarios in which positron emission tomography using radiolabeled 18F-fluorocholine can potentially be a cost-effective imaging option for primary hyperparathyroidism in the United States. Further investigation is needed to determine the maximal cost-effectiveness for positron emission tomography using radiolabeled 18F-fluorocholine in selected populations.

A Novel Mouse Model of Radiation-Induced Cardiac Injury Reveals Biological and Radiological Biomarkers of Cardiac Dysfunction with Potential Clinical Relevance.

Radiation-induced cardiotoxicity is a significant concern in thoracic oncology patients. However, the basis for this disease pathology is not well characterized. We developed a novel mouse model of radiation-induced cardiotoxicity to investigate pathophysiologic mechanisms and identify clinically targetable biomarkers of cardiac injury. Single radiation doses of 20, 40, or 60 Gy were delivered to the cardiac apex of female C57BL/6 mice ages 9-11 weeks, with or without adjacent lung tissue, using conformal radiotherapy. Cardiac tissue was harvested up to 24 weeks post-radiotherapy for histologic analysis. Echocardiography and Technetium-99m sestamibi single photon emission computed tomography (SPECT) at 8 and 16 weeks post-radiotherapy were implemented to evaluate myocardial function and perfusion. Mouse cardiac tissue and mouse and human plasma were harvested for biochemical studies. Histopathologically, radiotherapy resulted in perivascular fibrosis 8 and 24 (P < 0.05) weeks post-radiotherapy. Apical perfusion deficits on SPECT and systolic and diastolic dysfunction on echocardiography 8 and 16 weeks post-radiotherapy were also observed (P < 0.05). Irradiated cardiac tissue and plasma showed significant increases in placental growth factor (PlGF), IL6, and TNFα compared with nonradiated matched controls, with greater increases in cardiac cytokine levels when radiotherapy involved lung. Human plasma showed increased PlGF (P = 0.021) and TNFα (P = 0.036) levels after thoracic radiotherapy. PlGF levels demonstrated a strong correlation (r = 0.89, P = 0.0001) with mean heart dose. We developed and characterized a pathophysiologically relevant mouse model of radiation-induced cardiotoxicity involving in situ irradiation of the cardiac apex. The model can be used to integrate radiomic and biochemical markers of cardiotoxicity to inform early therapeutic intervention and human translational studies.

Use of Preoperative Imaging in Primary Hyperparathyroidism.

Preoperative imaging is performed routinely to guide surgical management in primary hyperparathyroidism, but the optimal imaging modalities are debated. Our objectives were to evaluate which imaging modalities are associated with improved cure rate and higher concordance rates with intraoperative findings. A secondary aim was to determine whether additive imaging is associated with higher cure rate. This is a retrospective cohort review of 1485 adult patients during a 14-year period (2004-2017) at an academic tertiary referral center that presented for initial parathyroidectomy for de novo primary hyperparathyroidism. Surgical cure rate, concordance of imaging with operative findings, and imaging performance. The overall cure rate was 94.1% (95% confidence interval, 0.93-0.95). Cure rate was significantly improved if sestamibi/single-photon emission computed tomography (SPECT) was concordant with operative findings (95.9% vs. 92.5%, P = 0.010). Adding a third imaging modality did not improve cure rate (1 imaging type 91.8% vs. 2 imaging types 94.4% vs. 3 imaging types 87.2%, P = 0.59). Despite having a low number of cases (n = 28), 4-dimensional (4D) CT scan outperformed (higher sensitivity, specificity, positive predictive value, negative predictive value) all imaging modalities in multiglandular disease and double adenomas, and sestamibi/SPECT in single adenomas. Preoperative ultrasound combined with sestamibi/SPECT were associated with the highest cure and concordance rates. If pathology was not found on ultrasound and sestamibi/SPECT, additional imaging did not improve the cure rate or concordance. 4D CT scan outperformed all imaging modalities in multiglandular disease and double adenomas, and sestamibi/SPECT in single adenomas, but these findings were underpowered.

Fluorine-18 fluorodeoxyglucose positron emission tomography in assessing myocardial viability in a tertiary academic centre in Johannesburg, South Africa: a pilot study.

Positron emission tomography detects patients with myocardial contractile dysfunction secondary to ischaemic heart disease who may benefit from coronary revascularisation. We reviewed technetium-99m sestamibi singlephoton emission computed tomography (SPECT) and fluorine-18 fluorodeoxyglucose (F18-FDG) positron emission tomography (PET) data from 236 patients imaged between January 2009 and June 2015. The patients were grouped into three groups: no evidence of viability, viability 1-10% and viability > 10%. Viability exceeding 10% was evident in 55% of the patients. On multivariate analysis, aspirin intake [OR: 1.92; 95% CI: 1.08-3.41; p = 0.026] and hypertension [OR: 1.89; 95% CI: 1.07-3.33; p = 0.029] were clinical factors associated with the presence of myocardial viability. Our study demonstrated that F18-FDG PET was able to identify 55% of patients with ischaemic heart disease with viability in more than 10% of the total myocardium when using a 17-segment model.

Incremental Value of Sestamibi SPECT/CT Over Dual-Phase Planar Scintigraphy in Patients With Primary Hyperparathyroidism and Inconclusive Ultrasound.

Background: We evaluated the incremental value of [99mTc]sestamibi single photon-emission computed tomography (SPECT)/computed tomography (CT) over planar imaging for localization of abnormal parathyroid tissue in patients with primary hyperparathyroidism.Methods: Forty-six patients with biochemical evidence of hyperparathyroidism and inconclusive ultrasound underwent sestamibi dual-phase planar scintigraphy and SPECT/CT for preoperative localization of parathyroid adenoma. Imaging findings were compared with histopathological data. Decision tree analysis was performed to evaluate the value of SPECT/CT over planar scintigraphy for classifying patients with or without hyperfunctioning parathyroid tissue. The added value of SPECT/CT was also evaluated by decision curve analysis.Results: Planar scintigraphy was positive for presence of hyperfunctioning parathyroid in 52% of patients, with sensitivity of 63% and specificity of 100%. SPECT/CT was positive in 80% of patients with sensitivity of 97% and specificity of 100%. At decision tree analysis, after an initial split on planar imaging results, no further split was performed in patients with positive results, while those with negative results were further stratified by SPECT/CT. At decision curve analysis, the model including SPECT/CT was associated with the highest net benefit compared to the model including only planar technique and to a strategy considering that all patients should be treated.Conclusion: Sestamibi SPECT/CT provides incremental value over dual-phase scintigraphy in preoperative localization of hyperfunctioning parathyroid tissue in subjects with inconclusive ultrasound. Hybrid technique allows a better identification of pathological lesion to perform minimally invasive surgery and showed the highest net benefit, improving selection of surgical approach.

Detection of anthracycline-induced cardiotoxicity using perfusion-corrected 99mTc sestamibi SPECT

By the time cardiotoxicity-associated cardiac dysfunction is detectable by echocardiography it is often beyond meaningful intervention. 99mTc-sestamibi is used clinically to image cardiac perfusion by single photon emission computed tomography (SPECT) imaging, but as a lipophilic cation its distribution is also governed by mitochondrial membrane potential (ΔΨm). Correcting scans for variations in perfusion (using a ΔΨm-independent perfusion tracer such as (bis(N-ethoxy-N-ethyldithiocarbamato)nitrido 99mTc(V)) (99mTc-NOET) could allow 99mTc-sestamibi to be repurposed to specifically report on ΔΨm as a readout of evolving cardiotoxicity. Isolated rat hearts were perfused within a γ-detection apparatus to characterize the pharmacokinetics of 99mTc-sestamibi and 99mTc-NOET in response to mitochondrial perturbation by hypoxia, ionophore (CCCP) or doxorubicin. All interventions induced 99mTc-sestamibi washout; hypoxia from 24.9 ± 2.6% ID to 0.4 ± 6.2%, CCCP from 22.8 ± 2.5% ID to −3.5 ± 3.1%, and doxorubicin from 23.0 ± 2.2% ID to 17.8 ± 0.7, p < 0.05. Cardiac 99mTc-NOET retention (34.0 ± 8.0% ID) was unaffected in all cases. Translating to an in vivo rat model, 2 weeks after bolus doxorubicin injection, there was a dose-dependent loss of cardiac 99mTc-sestamibi retention (from 2.3 ± 0.3 to 0.9 ± 0.2 ID/g with 10 mg/kg (p < 0.05)), while 99mTc-NOET retention (0.93 ± 0.16 ID/g) was unaffected. 99mTc-NOET therefore traps in myocardium independently of the mitochondrial perturbations that induce 99mTc-sestamibi washout, demonstrating proof-of-concept for an imaging approach to detect evolving cardiotoxicity.

Relationship between the infarct localization and left ventricular rotation parameters following acute ST-segment elevation myocardial infarction.

This study was an investigation of the role of left ventricular (LV) apical rotation seen in the early period after myocardial infarction (MI) in predicting infarct localization. A total of 124 patients with a ST-Segment elevation myocardial infarction (STEMI) diagnosis who underwent primary percutaneous coronary intervention (PCI) and 50 healthy volunteers with similar demographic characteristics were included in the study. The relationship between 2-dimenstional speckle tracking echocardiography (STE)-guided LV apical rotation angle measurements and technetium-99m sestamibi-single-photon emission computed tomography (SPECT)-guided infarct localization was evaluated. Conventional echocardiography and STE were performed on average 2 days after PCI, and gated SPECT myocardial perfusion imaging (MPI) was performed within an average of 60 days. The apical rotation angle was lower in patients with an anterior MI compared with those who had an inferior MI and the control group (AntMI-InfMI: 6.51±2.4°, AntMI-Control: 13.20±2.5°, InfMI-Control: 14.3±2.1°; p value: 0.00, 0.00, 0.15, respectively). SPECT MPI analysis revealed the presence of an LV apical scar in all patients with acute anterior MI, but only 14 of those with inferior MI group (usually the inferoapical wall). The apical rotation angle recorded in patients with apical scar was lower than that of the patients without apical scar (7.6±2.8° and 14.5±2°, respectively; p=0.00). Receiver operating characteristic curve analysis yielded an area under the curve for apical rotation of 0.799 (p<0.01). The optimal cutoff value of 12.1° had a sensitivity of 78.3% and a specificity of 68.2% for predicting LV apical scar following STEMI. Detection of apical rotation angle decrease in the early period after STEMI may be useful in predicting extension of infarct scarring to the LV apex.

Relationship Between Infarct Size and Outcomes Following Primary PCI: Patient-Level Analysis From 10 Randomized Trials

BackgroundPrompt reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) reduces infarct size and improves survival. However, the intuitive link between infarct size and prognosis has not been convincingly demonstrated in the contemporary era. ObjectivesThis study sought to determine the strength of the relationship between infarct size assessed early after primary percutaneous coronary intervention (PCI) in STEMI and subsequent all-cause mortality, reinfarction, and hospitalization for heart failure. MethodsWe performed a pooled patient-level analysis from 10 randomized primary PCI trials (total 2,632 patients) in which infarct size was assessed within 1 month after randomization by either cardiac magnetic resonance (CMR) imaging or technetium-99m sestamibi single-photon emission computed tomography (SPECT), with clinical follow-up for ≥6 months. ResultsInfarct size was assessed by CMR in 1,889 patients (71.8%) and by SPECT in 743 patients (28.2%). Median (25th, 75th percentile) time to infarct size measurement was 4 days (3, 10 days) after STEMI. Median infarct size (% left ventricular myocardial mass) was 17.9% (8.0%, 29.8%), and median duration of clinical follow-up was 352 days (185, 371 days). The Kaplan-Meier estimated 1-year rates of all-cause mortality, reinfarction, and HF hospitalization were 2.2%, 2.5%, and 2.6%, respectively. A strong graded response was present between infarct size (per 5% increase) and subsequent mortality (Cox-adjusted hazard ratio: 1.19 [95% confidence interval: 1.18 to 1.20]; p < 0.0001) and hospitalization for heart failure (adjusted hazard ratio: 1.20 [95% confidence interval: 1.19 to 1.21]; p < 0.0001), independent of age, sex, diabetes, hypertension, hyperlipidemia, current smoking, left anterior descending versus non–left anterior descending infarct vessel, symptom-to-first device time, and baseline TIMI (Thrombolysis In Myocardial Infarction) flow 0/1 versus 2/3. Infarct size was not significantly related to subsequent reinfarction. ConclusionsInfarct size, measured by CMR or technetium-99m sestamibi SPECT within 1 month after primary PCI, is strongly associated with all-cause mortality and hospitalization for HF within 1 year. Infarct size may, therefore, be useful as an endpoint in clinical trials and as an important prognostic measure when caring for patients with STEMI.

Cardiac ⁹⁹mTc sestamibi SPECT and ¹⁸F FDG PET as viability markers in Takotsubo cardiomyopathy.

In patients with heart failure (HF) due to coronary disease, a combined evaluation of perfusion and glucose metabolism by cardiac single photon emission computed tomography (SPECT)/positron emission tomography (PET) can be used to distinguish viable from non-viable myocardium, and current guidelines recommend cardiac SPECT and fluorodeoxyglucose (FDG) PET for viability assessment. Takotsubo cardiomyopathy (TTC) is a disease characterized by acute but reversible HF leaving no scarring. To explore how robust the semi-quantitative viability criteria used in cardiac SPECT and FDG PET stands their ground in a population with TTC. From 1 September 2009 to 1 October 2012, 24 patients suspected of TTC were enrolled in a multimodality cardiac imaging research project. Echocardiography, (99m)Tc SPECT, and (18)F FDG PET were performed during the acute admission and at follow-up 4 months later. Nineteen patients had a final diagnosis of TTC consistent with Mayo Clinic Diagnostic Criteria. Three of these patients were excluded from further analysis, since wall motion abnormalities were not persistent at the time of nuclear imaging. The remaining sixteen patients exhibited a distinct pattern with HF, "apical ballooning" and a perfusion-metabolism defect in the midventricular/apical region. When viability criteria were applied, they identified significant scarring/limited hibernation in the akinetic part of the left ventricle. However, full recovery was found in all TTC patients on follow-up. Using the current guideline-endorsed viability criteria for semiquantitative cardiac SPECT and FDG PET, these modalities failed to demonstrate the presence of viability in the acute state of TTC.

Assessment of myocardial viability and left ventricular function in patients supported by a left ventricular assist device

Chronically supported left ventricular assist device (LVAD) patients may be candidates for novel therapies aimed at promoting reverse remodeling and myocardial recovery. However, the effect of hemodynamic unloading with a LVAD on myocardial viability and LV function in chronically supported LVAD patients has not been fully characterized. We aimed to develop a non-invasive imaging protocol to serially quantify native cardiac structure, function, and myocardial viability while at reduced LVAD support. Clinically stable (n = 18) ambulatory patients (83% men, median age, 61 years) supported by a HeartMate II (Thoratec, Pleasanton, CA) LVAD (median durations of heart failure 4.6 years and LVAD support 7 months) were evaluated by echocardiography and technetium-99m ((99m)Tc)-sestamibi single photon emission computed tomography (SPECT) imaging at baseline and after an interval of 2 to 3 months. Echocardiographic measures of LV size and function, including speckle tracking-derived circumferential strain, were compared between ambulatory and reduced LVAD support at baseline and between baseline and follow-up at reduced LVAD support. The extent of myocardial viability by SPECT was compared between baseline and follow-up at reduced LVAD support. With reduction in LVAD speeds (6,600 rpm; interquartile range: 6,200, 7,400 rpm), LV size increased, LV systolic function remained stable, and filling pressures nominally worsened. After a median 2.1 months, cardiac structure, function, and the extent of viable myocardium, globally and regionally, was unchanged on repeat imaging while at reduced LVAD speed. In clinically stable chronically supported LVAD patients, intrinsic cardiac structure, function, and myocardial viability did not significantly change over the pre-specified time frame. Echocardiographic circumferential strain and (99m)Tc-sestamibi SPECT myocardial viability imaging may provide useful non-invasive end points for the assessment of cardiac structure and function, particularly for phase II studies of novel therapies aimed at promoting reverse remodeling and myocardial recovery in LVAD patients.

The application of SPECT/CT for preoperative planning in patients with secondary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) is a frequent and challenging issue in patients undergoing dialysis for chronic kidney disease. Surgical intervention in the form of parathyroidectomy is generally considered only in cases of severe SHPT. However, identification of the exact location of the parathyroid glands (PTGs) before parathyroidectomy is a challenge. The aim of this study was to evaluate the role of 99mTc sestamibi single-photon emission computed tomography (SPECT)/computed tomography (CT) in the detection of parathyroids to guide operative therapy in patients with SHPT. Ninety patients with SHPT who were on hemodialysis were evaluated preoperatively with double-phase 99mTc sestamibi static planar and SPECT/CT parathyroid scintigraphy to evaluate for parathyroids before parathyroidectomy. The sensitivity, specificity, and accuracy of 99mTc sestamibi static planar and SPECT/CT scintigraphy were determined. Compared with static planar scintigraphy, 99mTc sestamibi SPECT/CT was able to detect a larger number of PTGs per study, as well as PTGs of smaller diameter and PTGs of smaller size. The sensitivity, specificity, and accuracy of 99mTc sestamibi SPECT/CT in detecting PTGs were 78.9, 100, and 78.9%, respectively, compared with 55.6, 100, and 55.6% for static planar 99mTc sestamibi. Our study indicates that 99mTc sestamibi SPECT/CT has a higher sensitivity compared with static planar scintigraphy in the preoperative evaluation of hemodialysis patients with SHPT because of chronic kidney disease. SPECT/CT can not only detect a larger number of PTGs but can also depict the precise location of PTGs more accurately when compared with static planar scintigraphy.

The use of positron emission tomography with 11C-methionine in patients with primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disorder, which is nowadays often discovered incidentally by the finding of increased serum calcium and PTH in routine blood tests [1]. PHPT is due to a single adenoma in the majority of cases (85–90 %), whereas hyperplasia of all parathyroid glands occurs in 10–15 % and carcinoma is found in less than 1 %. PHPT may occur sporadically or as a part of hereditary forms [2]. Pathological parathyroid glands are mainly located close to the thyroid gland, but ectopic localization in the mediastinum, or lateral to the carotid sheath, in the carotid bifurcation and very rarely within the thyroid or the thymus may occur in up to 20 % of cases [3]. Parathyroidectomy (PTx) is the only definitive cure of PHPT and, if performed by an experienced endocrine surgeon, is successful in up to 95 % of cases. In recent years, the minimally invasive PTx (MIP) has almost replaced the traditional full neck exploration [4]. A preoperative identification of the enlarged parathyroid lesion(s) is required to perform MIP [5]. Many imaging techniques are available for locating enlarged parathyroid glands, but Tc sestamibi scan and cervical ultrasound are the most commonly used [5]. Sestamibi is taken up both by thyroid and parathyroid tissues, but it persists longer in the latter; thus a late scan can show an uptake which is rather specific for the parathyroid gland. Planar parathyroid scintigraphy may miss small or ectopic lesions. The single photon emission computed tomography (SPECT) may be helpful for giving a more precise localization of enlarged parathyroid gland(s). The sensitivity varies in different series and may reach 90–95 % using SPECT, but may be lower using planar scintigraphy [6]. The sensitivity for small adenomas, double adenomas or hyperplasia is much lower, and in the latter case computed tomography (CT)-sestamibi SPECT image fusion is superior to CT or sestamibi SPECT alone [7]. Neck ultrasound is a widely available, safe and low-cost technique and may identify a coexisting thyroid disease. The accuracy of neck ultrasound is operator-dependent. Its sensitivity can range from 42 to 82 % with a specificity of approximately 90 % [8]. CT of the neck and mediastinum and magnetic resonance imaging (MRI) are generally used in patients with persistent or recurrent PHPT, or when ultrasound and sestamibi imaging studies are negative or contradictory [5]. The TC sensitivity ranges from 50 to 88 % [5]. MRI is time-consuming and less sensitive than TC. Invasive localization techniques such as arteriography and selective venous sampling for PTH assay in the draining thyroid veins are nowadays rarely used and could be reserved to patients with prior PTx and negative imaging studies [5]. Positron emission tomography (PET) has a spatial resolution higher than that of sestamibi scintigraphy and, alone or with simultaneous CT scan (PET/CT), could be an useful tool for the identification of enlarged parathyroid glands in patient with persistent or recurrent PHPT when the results of other imaging techniques are negative or conflicting. In patients with PHPT, the PET with F-fluorodeoxyglucose (FDG-PET) showed a diagnostic accuracy lower than that of sestamibi SPECT. On the other hand, PET with C-methionine (C-Met-PET) has a sensitivity higher than that of FDG-PET [9]. C-methionine is considered to be more specific, since C-methionine seems to concentrate specifically in the enlarged parathyroid F. Cetani (&) C. Marcocci Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy e-mail: cetani@endoc.med.unipi.it

Tc-99m SPECT Sestamibi for the Measurement of Infarct Size

There are a variety of approaches to assess the efficacy of reperfusion therapy, and myocardial protection, in acute myocardial infarction. This review summarizes the available evidence validating the use of technetium-99m sestamibi single-photon emission computed tomography (SPECT) for this purpose. Multiple lines of evidence have validated its clinical utility. SPECT sestamibi infarct size has been used as an endpoint in multiple randomized clinical trials. A smaller number of clinical trials have used both early and later imaging with SPECT sestamibi to assess myocardium at risk and myocardial salvage. SPECT sestamibi has a number of limitations which must be recognized. Nevertheless, SPECT sestamibi infarct size is a well-validated measurement with a long track record of performance as an endpoint in multicenter, randomized clinical trials.

Role of Noninvasive Imaging in the Diagnosis of Cardiac Allograft Vasculopathy

Cardiac allograft vasculopathy (CAV) is common, with a prevalence of 52% at 10 years after transplantation, and represents a leading cause of death beyond the first year, responsible for approximately 15% of deaths annually.1 It is characterized by diffuse and concentric intimal proliferation, typically involving the intramural as well as epicardial coronary arteries. Its diagnosis is difficult to establish clinically because of denervation of the transplanted heart. Consequently, it presents late with silent myocardial infarction, progressive heart failure, or arrhythmic sudden death.2 Screening is therefore required for its early detection. Although coronary intravascular ultrasound (IVUS) is considered the gold-standard technique for detecting the anatomic features of CAV (Table 1), its broad clinical use in this context is limited by cost and lack of widespread expertise, and its evaluation is limited to epicardial vessels.3 Coronary angiography, performed annually or biannually, remains the most common clinical screening method.4 However, because of the diffuse nature of CAV with a lack of normal reference segments and the relatively late occurring luminal narrowing, the sensitivity of angiography is as low as 30% when compared with IVUS (Figure 1).5 As a result, complications frequently occur before disease is evident angiographically.6 Furthermore, angiography is associated with significant albeit uncommon complications (overall complication rate, 7.4/1000 procedures, including rates of 0.65/1000, 1.6/1000, and 0.72/1000 for cerebrovascular accidents, vascular complications, and death, respectively), is disliked by transplant recipients, is costly, and repeated studies are associated with an important cumulative radiation dose.7 View this table: Table 1. Stanford Classification of CAV Severity on IVUS Figure 1. Invasive assessment of cardiac allograft vasculopathy (CAV) in a patient with severe disease, highlighting the limited sensitivity of conventional coronary angiography. Although no left anterior descending (LAD) flow-limiting stenoses are seen on angiography ( A ), intravascular ultrasound ( B ) shows significant intimal thickening, measuring up to …

Incremental prognostic value of coronary flow reserve assessed with single-photon emission computed tomography

BackgroundWe assessed the prognostic value of coronary flow reserve (CFR) estimated by single-photon emission computed tomography (SPECT) in patients with suspected myocardial ischemia. Methods and ResultsMyocardial perfusion and CFR were assessed in 106 patients using dipyridamole/rest Tc-99m sestamibi SPECT and follow-up was obtained in 103 (97%) patients. Four early revascularized patients were excluded and 99 were assigned to normal (summed stress score <3) vs abnormal myocardial perfusion and to normal (≥2.0) vs abnormal CFR. During the follow-up (5.8 ± 2.1 years), 28 patients experienced a cardiac event (cardiac death, nonfatal myocardial infarction, and late revascularization). Abnormal perfusion (P < .01) and abnormal CFR (P < .05) were independent predictors of cardiac events at Cox proportional hazard regression analysis. Also in patients with normal perfusion, abnormal CFR was associated with a higher annual event rate compared with normal CFR (5.2% vs 0.7%; P < .05). CFR data improved the prognostic power of the model including clinical and myocardial perfusion data increasing the global chi-square from 18.6 to 22.8 (P < .05). Finally, at parametric survival analysis, in patients with normal perfusion the time to achieve ≥2% risk of events was >60 months in those with normal and <12 months in those with abnormal CFR. ConclusionsMyocardial perfusion findings and CFR at SPECT imaging are both independent predictors of cardiac events. Estimated CFR provides incremental prognostic information over those obtained from clinical and myocardial perfusion data, particularly in patients with normal perfusion findings.

Male breast uptake of 99m-Tc sestamibi in myocardial perfusion imaging

Standard interpretation of single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) studies include analysis of the rest and stress perfusion images as well as evaluation of left ventricular function. However, it is also important to carefully review the rotating cinematic raw projections “rotatograms” for factors that may influence the interpretation and non-cardiac findings. Non-cardiac findings from rotating cinematic images have identified both benign and malignant conditions [ 1 Williams K.A. Hill K.A. Sheridan C.M. Noncardiac findings on dual-isotope myocardial perfusion SPECT. J Nucl Cardiol. 2003; 10: 395-402 Google Scholar , 2 Jones S.E. Aziz K. Yasuda T. Gewirtz H. Scott J.A. Importance of systematic review of rotating projection images from Tc99m-sestamibi cardiac perfusion imaging for noncardiac findings. Nucl Med Commun. 2008; 29: 607-613 Google Scholar ]. We report two male patients who underwent stress technetium 99m sestamibi SPECT and were found to have increased focal tracer uptake identified in the breast region on the rotating cine images; case 1 had a diagnosis of invasive ductal adenocarcinoma of the breast and case 2 had bilateral gynecomastia.

A Meta-analysis of Preoperative Localization Techniques for Patients with Primary Hyperparathyroidism

Reported accuracy of preoperative localization imaging for primary hyperparathyroidism (pHPT) varies. The purpose of this study is to determine the accuracy of ultrasound, sestamibi-single photon emission computed tomography (SPECT), and four-dimensional computed tomography (4D-CT) as preoperative localization strategies. A meta-analysis was performed of studies investigating the accuracy of ultrasound, sestamibi-SPECT, and 4D-CT for preoperative localization in pHPT. Electronic databases were systematically searched, and two independent reviewers reviewed results using specific criteria. Study quality was assessed using a validated measure for diagnostic imaging studies. Study heterogeneity and pooled results were calculated. 43 studies met criteria for inclusion, and data were available for extraction in 19 ultrasound, 9 sestamibi-SPECT, and 4 4D-CT studies. Ultrasound had pooled sensitivity and positive predictive value (PPV) of 76.1% (95% CI 70.4-81.4%) and 93.2% (90.7-95.3%), respectively. Sestamibi-SPECT had pooled sensitivity and PPV of 78.9% (64-90.6%) and 90.7% (83.5-96.0%), respectively. Only two 4D-CT studies investigated patients undergoing initial parathyroidectomy. Results suggested sensitivity and PPV of 89.4% and 93.5%, respectively. Ultrasound and sestamibi-SPECT are similar in ability to preoperatively localize abnormal parathyroid glands in pHPT. Accuracy may be improved with 4D-CT; however, further investigation is required. Choice of preoperative imaging strategy depends on numerous patient, institutional, and economic factors of which the surgeon must be aware.

One-year prognosis of patients with normal myocardial perfusion imaging using technitium-99m sestamibi in suspected coronary artery disease: a single-center experience of 1,047 patients

The aim of the present study was to evaluate the clinical outcome of a normal stress technetium-99m (99mTc)-Sestamibi single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with different probabilities of coronary artery disease (CAD). A total of 1,047 subjects with a normal 99mTc-MIBI SPECT were followed up for one year and hard and soft cardiac events were assessed. Hard cardiac events were defined as cardiac death or non-fatal myocardial infarction (MI). Soft cardiac events included the patient's development of recurrent chest pain requiring coronary revascularization or significant stenosis in coronary arteries on angiography. Overall, 1,047 patients (248 men and 799 women; mean age: 60.07 ± 12.31, range 29-92) were enrolled. Three hard cardiac events occurred in the groups; two had cardiac arrest and one non-fatal MI. As a result, the annualized hard cardiac event rate was 0.28%, the annualized cardiac mortality rate was 0.19%, and the rate of overall annualized cardiac events was 1.25%. Furthermore, there was a significant difference in cardiac events among patients with various pretest likelihoods of CAD (p value=0.04). Our data confirmed that patients with a normal 99mTc-Sestamibi myocardial SPECT are associated with a very low incidence of cardiovascular events.

The Occluded Artery Trial (OAT) Viability Ancillary Study (OAT-NUC): Influence of infarct zone viability on left ventricular remodeling after percutaneous coronary intervention versus optimal medical therapy alone

The Occluded Artery Trial (OAT) showed no difference in outcomes between percutaneous coronary intervention (PCI) versus optimal medical therapy (MED) in patients with persistent total occlusion of the infarct-related artery 3 to 28 days post-myocardial infarction. Whether PCI may benefit a subset of patients with preservation of infarct zone (IZ) viability is unknown. The OAT nuclear ancillary study hypothesized that (1) IZ viability influences left ventricular (LV) remodeling and that (2) PCI as compared with MED attenuates adverse remodeling in post-myocardial infarction patients with preserved viability. Enrolled were 124 OAT patients who underwent resting nitroglycerin-enhanced technetium-99m sestamibi single-photon emission computed tomography (SPECT) before OAT randomization, with repeat imaging at 1 year. All images were quantitatively analyzed for infarct size, IZ viability, LV volumes, and function in a core laboratory. At baseline, mean infarct size was 26% ± 18 of the LV, mean IZ viability was 43% ± 8 of peak uptake, and most patients (70%) had at least moderately retained IZ viability. There were no significant differences in 1-year end-diastolic or end-systolic volume change between those with severely reduced versus moderately retained IZ viability, or when compared by treatment assignment PCI versus MED. In multivariable models, increasing baseline viability independently predicted improvement in ejection fraction (P = .005). There was no interaction between IZ viability and treatment assignment for any measure of LV remodeling. In the contemporary era of MED, PCI of the infarct-related artery compared with MED alone does not impact LV remodeling irrespective of IZ viability.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries