Imaging Acute Myocarditis with 68Ga-DOTANOC PET/CT.

Somatostatin receptor (SSTR) imaging is a useful method in the diagnosis of acute myocarditis. We present a case of a 54-year-old male with a clinical diagnosis of acute myocarditis in whom, 68Ga-DOTANOC positron emission tomography/computed tomography PET/CT showed diffuse left ventricular myocardial uptake. SSTR imaging can act as a surrogate marker of active inflammation. SSTR imaging is useful in deciding site of biopsy, assessing response to therapy and for prognostication.

Evaluation of CYFRA 21.1 as a Dedifferentiation Marker of Advanced Thyroid Cancer.

PURPOSE OF THE STUDY: Well-differentiated thyroid carcinomas have good prognosis, but as it de-differentiates, the survival rates go down. Early identification of such patients needs a marker which indicates the dedifferentiation process. CYFRA 21.1 has also shown to be increased in patients with 131I refractory thyroid cancer. We tested whether CYFRA 21.1 can differentiate between 131I avid and refractory tumors. METHODOLOGY: Well-differentiated thyroid cancer patients with known distant metastases were accrued and tested for stimulated and unstimulated thyroglobulin and CYFRA 21.1. All patients underwent 131I whole-body scan, 131I post therapy scan, and 18F-Fluorodeoxyglucose positron emission tomography-computed tomography. Those with even a single 131I nonavid lesion were considered 131I refractory disease. CYFRA 21.1 of both 131I avid and nonavid was compared, and CYFRA 21.1 levels against disease extent were analyzed. RESULTS: CYFRA 21.1 levels were significantly elevated in 131I refractory group. A cutoff value of 2.07 ng/ml distinguished between 131I avid and refractory disease with high sensitivity and specificity (88% and 89. 7%, respectively). However, CYFRA 21.1 levels were similar in patients when analyzed based on disease sites. CONCLUSION: CYFRA 21.1 can be utilized to differentiate between 131I avid and refractory diseases. Further long-term studies are required to use it as a predictive and prognostic marker.

Assessment of asymptomatic ischemic heart disease using stress myocardial perfusion imaging in patients with type 2 diabetes mellitus.

BACKGROUND: Coronary artery disease (CAD) is the leading cause of death in patients with type 2 diabetes mellitus (T2DM) and may be asymptomatic. OBJECTIVE: The objective of this study was to assess the prevalence of asymptomatic myocardial ischemia in patients with T2DM using stress myocardial perfusion imaging. METHODS: We evaluated 97 consecutive patients with T2DM without clinical evidence of CAD presenting to Cardiology and Endocrinology clinics using Tc-99m MIBI gated single-photon emission-computed tomography (SPECT) myocardial perfusion imaging for the presence of asymptomatic CAD. RESULTS: Abnormal myocardial perfusion was observed in 10 patients (10.3%). Of these, one half of patients had reversible myocardial perfusion defects suggestive of inducible myocardial ischemia. The other half had fixed perfusion defects suggestive of previous silent myocardial infarctions. Small and moderate reversible perfusion defects were observed in 3 and 2 patients, respectively. The fixed perfusion defects observed in 5 patients were medium sized. The presence of asymptomatic ischemia was significantly associated with age and smoking but not with other traditional cardiac risk factors. CONCLUSION: Ten percent of patients with T2DM with no clinical evidence of CAD were found to have evidence of asymptomatic ischemia or infarction.

Role of Various Metabolic Parameters Derived From Baseline 18F-FDG PET/CT as Prognostic Markers in Non-Small Cell Lung Cancer Patients Undergoing Platinum-Based Chemotherapy.

PURPOSE: The aim of this study was to prospectively evaluate the role of various quantitative and semiquantitative metabolic parameters derived from dynamic and static baseline F-FDG PET/CT in prediction of overall survival (OS) in non-small cell lung cancer (NSCLC) patients who were planned to undergo platinum-based chemotherapy. METHODS: Sixty patients (51 male and 9 female patients) with biopsy-proven NSCLC and mean age 59.55 ± 10.06 years who were planned to undergo platinum-based chemotherapy were enrolled in the study. Each patient underwent a baseline regional dynamic and a static whole-body F-FDG PET/CT after injecting 0.21 mCi/kg (5.18-7.77 MBq/kg) of F-FDG intravenously. Two dynamic PET/CT parameters, that is, net influx rate constant and glucose metabolic rate at 30 and 60 minutes, were evaluated. In addition, whole-body PET/CT parameters, that is, SUVmax, average SUV, tumor-to-background ratio, metabolic tumor volume (MTV), total lesion glycolysis (TLG) of the primary tumor, and MTV and TLG of whole-body tumor lesions, were evaluated. Best possible cutoffs for all parameters were calculated using receiver operating characteristic curve analysis. Survival analysis was performed using log-rank test, Kaplan-Meier curves, and Cox proportional hazards model to determine the prognostic markers for OS. RESULTS: The median follow-up period was 4.4 months (range, 8 days to 15.9 months). In univariate analysis, the 4 static whole-body PET/CT parameters, that is, MTV, TLG, and MTV and TLG of whole-body tumor lesions, were found to be significantly associated with OS with cutoff values of 120, 800, 160, and 1350 cm and hazard ratios of 3.64 (P = 0.001), 3.35 (P = 0.002), 2.51 (P = 0.019), and 2.69 (P = 0.008), respectively. In multivariate survival analysis, MTV was found to be an independent prognostic marker for OS. CONCLUSIONS: Baseline MTV and TLG evaluated from primary tumor as well as the whole-body tumor lesions are reliable prognostic markers of OS in NSCLC patients undergoing platinum-based chemotherapy. However, other baseline whole-body PET/CT parameters (SUVmax, average SUV, and tumor-to-background ratio) and dynamic PET/CT parameters (net influx rate constant, glucose metabolic rate) have no prognostic value in these patients.

Clinical significance of intracoronary thrombus aspirated during primary percutaneous intervention: An immunohistopathological study.

BACKGROUND: Manual thrombus aspiration during primary percutaneous intervention provides us with aspirated thrombus sample, that may contain material from the disrupted plaque. Immunohistopathological analysis of thrombus can yield valuable information about the clinical and cardiovascular outcomes and possible mechanisms of myocardial infarction. MATERIAL AND METHODS: We studied and analysed the immunohistopathological features of coronary thrombus aspirated from patients undergoing primary percutaneous coronary angioplasty. Immunohistological staining included markers namely CD68, SMA and CD34 for macrophages, smooth muscle actin and endothelium, respectively. Major adverse cardiac events, angiographic outcome and infarct size were also noted. RESULTS: Fifty-three patients (Mean age - 51.3±13years; males-47) who underwent primary percutaneous coronary intervention with aspiration thrombectomy were enrolled. Thrombus was successfully aspirated in 40 of 53 patients (75.4%). Patients with successful thrombus aspiration had higher ST-segment resolution (≥50%) as compared to patients with failed thrombus aspiration. Presence of RBC-rich thrombus on microscopy was more commonly associated with post-procedure TIMI flow of <2 as compared to patients with fibrin-rich thrombus and a trend towards lower myocardial blush grade<2 (P=0.10), and a significantly higher final infarct size (37.5±5% vs 25±15%; P=0.04 of myocardium) on nuclear scan. Immunohistology revealed presence of plaque material in 72% (26/36) of the samples. CONCLUSIONS: Immunohistopathological evaluation of intracoronary thrombus may be of prognostic importance. High prevalence of plaque material in the aspirated intracoronary thrombus suggests plaque rupture as a possible etiology for vessel occlusion in these patients. SHORT SUMMARY: Immunohistopathological evaluation of intracoronary thrombus reveals high prevalence of plaque material in the aspirated intracoronary thrombus suggesting plaque rupture as a possible etiology for vessel occlusion in Indian STEMI patients.

Detection of Thymoma on 99mTc MIBI Scintigraphy: Revisiting the Past.

Although thymoma is a rare tumor, it is the most common anterior mediastinal tumor, usually affecting the adults in their fifth and sixth decade. We present a case of 68-year-old man with history of myocardial infarction, who presented to the cardiology OPD with recent onset of exertional dyspnea. On 99mTc MIBI myocardial perfusion SPECT, there was an extra cardiac accumulation of radiotracer in the anterior mediastinum just above the heart, which later was diagnosed as thymoma on histopathology.

Interplay between right ventricular mechanical dyssynchrony and cardiac resynchronization therapy in patients with nonischemic dilated cardiomyopathy.

OBJECTIVE: The effect of cardiac resynchronization therapy (CRT) on right ventricular ejection fraction (RVEF) and intraright ventricular dyssynchrony (IRVD) is questionable. Furthermore, it is unclear whether baseline IRVD and RVEF influences response to CRT. The aim of this study is to evaluate the effects of CRT on RVEF and IRVD and to investigate whether baseline IRVD and RVEF impacts response to CRT. PATIENTS AND METHODS: Equilibrium radionuclide angiography and clinical evaluation were performed in 32 nonischemic dilated cardiomyopathy patients before and 3 months after CRT implantation. SD of the right ventricle mean phase angle expressed in degrees was used to quantify right intraventricular synchrony. RVEF was also evaluated. RESULTS: There was no significant change in the RVEF and IRVD between the baseline and at 3 months after CRT equilibrium radionuclide angiography studies (RVEF: 40.5±10.6 vs. 40.4±10.4%, P=0.75; IRVD: 36.6±13.7 vs. 36.3±13.3°, P=0.35). Of 32 patients, 6/14 (43%) patients with baseline IRVD responded compared with 16/18 (89%) without baseline IRVD (P=0.02). CONCLUSION: CRT did not cause any significant change in RVEF and IRVD. Patients with IRVD are less likely to respond to CRT.

Detection of perfusion abnormalities in patients with permanent pacemakers on stress-rest 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography: comparison between right ventricular apex and right ventricular outflow tract pacing.

OBJECTIVE: The aim of the study was to compare the myocardial perfusion defects in patients with right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing on stress-rest Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography. PATIENTS AND METHODS: A total of 31 patients with permanent pacemakers (RVOT: 16 and RVA: 15) underwent stress-rest Tc-tetrofosmin involving a 1-day protocol. All patients underwent 1-day low-dose stress-gated and high-dose rest-gated Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography imaging. RESULTS: Fixed perfusion defects were noted in 13 (42%) of 31 patients. Two (13%) patients of the RVOT group and 11 (69%) patients of the RVA group showed fixed perfusion defects (P=0.003). The fixed perfusion defects were located in the anteroapical, anteroseptal, and apical in the RVOT pacing group and in the apical, distal anteroseptal, inferoapical, distal anterior, and distal inferoseptal in the RVA pacing group. On univariate analysis, the incidence of perfusion defects was significantly associated with apical pacing, longer pQRS duration, and higher percentage of ventricular pacing. On multivariate analysis, the site of pacemaker insertion was found to be the most important pacemaker parameter determining the incidence of perfusion defects. Importantly, the duration of postpacemaker implantation did not show any significant relation to the incidence of perfusion defects. CONCLUSION: Fixed perfusion abnormalities are observed in patients with pacemakers and are independent of duration of time since implantation. RVOT pacing is associated with fewer incidences of myocardial perfusion abnormalities compared with RVA pacing.

Quantitative assessment of cardiac mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy in patients with non-ischaemic dilated cardiomyopathy using equilibrium radionuclide angiography.

AIMS: The aim of this study was to evaluate equilibrium radionuclide angiography (ERNA) in prediction of response to cardiac resynchronization therapy (CRT) in non-ischaemic dilated cardiomyopathy (DCM) patients. METHODS AND RESULTS: Thirty-two patients (23 males, 57.5 ± 12.1 years) were prospectively included. Equilibrium radionuclide angiography and clinical evaluation were performed before and 3 months after CRT implantation. Standard deviation of left ventricle mean phase angle (SD LVmPA) and difference between LV and right ventricle mPA (LV-RVmPA) expressed in degrees (°) were used to quantify left intraventricular synchrony and interventricular synchrony, respectively. Left ventricular ejection fraction (LVEF) was also evaluated. At the baseline, mean NYHA class was 3.3 ± 0.5, LVEF 22.5 ± 5.6%, mean QRS duration 150.3 ± 18.2 ms, SD LVmPA 43.5 ± 18°, and LV-RVmPA 30.4 ± 15.6°. At 3-month follow-up, 22 patients responded to CRT with improvement in NYHA class ≥1 and EF >5%. Responders had significantly larger SD LVmPA (51.2 ± 13.9 vs. 26.5 ± 14°) and LV-RVmPA (35.8 ± 13.7 vs. 18.4 ± 13°) than non-responders. Receiver-operating characteristic curve analysis demonstrated 95% sensitivity and 80% specificity at a cut-off value of 30° for SD LVmPA, and 81% sensitivity and 80% specificity at a cut-off value of 23° for LV-RVmPA in prediction of response to CRT. CONCLUSION: Baseline SD LVmPA and LV-RVmPA derived from ERNA are useful for prediction of response to CRT in non-ischaemic DCM patients.

Efficacy of stem cell in improvement of left ventricular function in acute myocardial infarction--MI3 Trial.

BACKGROUND & OBJECTIVES: Acute myocardial infarction (AMI) is characterized by irreparable and irreversible loss of cardiac myocytes. Despite major advances in the management of AMI, a large number of patients are left with reduced left ventricular ejection fraction (LVEF), which is a major determinant of short and long term morbidity and mortality. A review of 33 randomized control trials has shown varying improvement in left ventricular (LV) function in patients receiving stem cells compared to standard medical therapy. Most trials had small sample size and were underpowered. This phase III prospective, open labelled, randomized multicenteric trial was undertaken to evaluate the efficacy in improving the LVEF over a period of six months, after injecting a predefined dose of 5-10 × 10 [8] autologous mononuclear cells (MNC) by intra-coronary route, in patients, one to three weeks post ST elevation AMI, in addition to the standard medical therapy. METHODS: In this phase III prospective, multicentric trial 250 patients with AMI were included and randomized into stem cell therapy (SCT) and non SCT groups. All patients were followed up for six months. Patients with AMI having left ventricular ejection fraction (LVEF) of 20-50 per cent were included and were randomized to receive intracoronary stem cell infusion after successfully completing percutaneous coronary intervention (PCI). RESULTS: On intention-to-treat analysis the infusion of MNCs had no positive impact on LVEF improvement of ≥ 5 per cent. The improvement in LVEF after six months was 5.17 ± 8.90 per cent in non SCT group and 4.82 ± 10.32 per cent in SCT group. The adverse effects were comparable in both the groups. On post hoc analysis it was noted that the cell dose had a positive impact when infused in the dose of ≥ 5 X 10 [8] (n=71). This benefit was noted upto three weeks post AMI. There were 38 trial deviates in the SCT group which was a limitation of the study. INTERPRETATION & CONCLUSIONS: Infusion of stem cells was found to have no benefit in ST elevation AMI. However, the procedure was safe. A possible benefit was seen when the predefined cell dose was administered which was noted upto three weeks post AMI, but this was not significant and needs confirmation by larger trials.

Quantitative assessment of cardiac mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy in patients with nonischaemic dilated cardiomyopathy using gated myocardial perfusion SPECT.

OBJECTIVE: The aim of the study was to evaluate gated myocardial perfusion SPECT (GMPS) in the prediction of response to cardiac resynchronization therapy (CRT) in nonischaemic dilated cardiomyopathy patients. PATIENTS AND METHODS: Thirty-two patients (23 men, mean age 57.5±12.1 years) with severe heart failure, who were selected for CRT implantation, were prospectively included in this study. Patients with coronary heart disease and structural heart diseases were excluded. 99mTc-MIBI GMPS and clinical evaluation were performed at baseline and 3 months after CRT implantation. In GMPS, first-harmonic fast Fourier transform was used to extract a phase array using commercially available software. Phase standard deviation (PSD) and phase histogram bandwidth (PHB) were used to quantify cardiac mechanical dyssynchrony (CMD). Left ventricular ejection fraction was evaluated. RESULTS: At baseline evaluation the mean NYHA class was 3.3±0.5, left ventricular ejection fraction was 23.2±5.3% and mean QRS duration was 150.3±18.2 ms. PSD was 55.8±19.2° and PHB was 182.1±75.8°. At 3-month follow-up, 22 patients responded to CRT with improvement in NYHA class by more than 1 grade and in ejection fraction by more than 5%. Responders had significantly larger PSD (63.6±16.6 vs. 38.7±12.7°) and PHB (214.8±63.9 vs. 110.2±43.5°) compared with nonresponders. Receiver-operating characteristic curve analysis demonstrated 86% sensitivity and 80% specificity at a cutoff value of 43° for PSD and 86% sensitivity and 80% specificity at a cutoff value of 128° for PHB in the prediction of response to CRT. CONCLUSION: Baseline PSD and PHB derived from GMPS are useful for prediction of response to CRT in nonischaemic dilated cardiomyopathy patients.

Comparison of left ventricular systolic function and mechanical dyssynchrony using equilibrium radionuclide angiography in patients with right ventricular outflow tract versus right ventricular apical pacing: A prospective single-center study.

BACKGROUND: Chronic ventricular pacing is known to adversely affect left ventricular (LV) function. Studies comparing right ventricular outflow tract (RVOT) pacing with RV apical (RVA) pacing have shown heterogeneous outcomes. Our aim was to objectively assess LV function and mechanical dyssynchrony in patients with RVOT and RVA pacing using equilibrium radionuclide angiography (ERNA). METHODS: Fifty-one patients who underwent permanent pacemaker implantation and had normal LV function were prospectively included. Twenty-nine patients had pacemaker lead implanted in the RVOT and 22 at the RVA site. All patients underwent ERNA within 5 days post-pacemaker implantation and follow-up studies at 6 and 12 months. Standard deviation of LV mean phase angle (SD LV mPA) expressed in degrees, which was derived by Fourier first harmonic analysis of phase images, was used to quantify left intraventricular dyssynchrony. RESULTS: No significant difference was observed between the two groups with respect to indication (P = .894), Type/mode (P = .985), and percentage of ventricular pacing (P = .352). Paced QRS duration was significantly longer in RVA group than RVOT group (P = .05). There was no statistically significant difference between the RVA and RVOT groups at baseline with respect to LVEF (P = .596) and SD LV mPA (P = .327). Within the RVA group, a significant decline in LVEF was observed over 12-month follow-up (from 57.3% ± 5.32% to 55.6% ± 6.25%; P = .012). In the RVOT group, the change in LVEF was not statistically significant (from 56.7% ± 4.08% to 54.3% ± 6.63%; P = .159). No significant change in SD LV mPA was observed over 12-month follow-up within the RVA group (from 10.5 ± 2.58° to 10.4 ± 3.54°; P = 1.000) as well as in the RVOT group (from 9.7 ± 3.28° to 9.4 ± 2.85°; P = .769). However, between the RVA and RVOT groups, no significant difference was observed at 12-month follow-up in terms of LVEF and dyssynchrony (LVEF P = .488; SD LV mPA P = .296). CONCLUSION: No significant difference was observed between RVOT and RVA groups with regard to LV function and synchrony over a 12-month follow-up. RVOT pacing offers may lead to better preservation of LV function on longer follow-up.

Does perfusion pattern influence stress-induced changes in left ventricular mechanical dyssynchrony on thallium-201-gated SPECT myocardial perfusion imaging?

BACKGROUND: The relationship between perfusion pattern and stress-induced changes in left ventricular mechanical dyssynchrony (LVMD) on stress-rest thallium-201-gated SPECT myocardial perfusion imaging (Tl-201 SPECT MPI) is not clear. The aim of the study is to assess the relation of perfusion pattern with stress-induced changes in LVMD on Tl-201 MPI. METHODS: Data of 194 patients who underwent exercise-rest Tl-201 MPI between January to December 2012 at our institute was retrospectively evaluated. Institute Ethical committee approval was obtained. Fifty patients who underwent Tl-201 MPI for suspected CAD and had normal LV perfusion and function on MPI were taken as normal group. Patients with perfusion abnormalities (n = 144) were divided into three groups: ischemia (n = 66), infarct (n = 32), and mixed group (n = 46; ischemia and infarct both). Summed stress score, summed rest score, summed difference score (SDS), and LV ejection fraction (EF) were evaluated. Two LVMD parameters, phase standard deviation (PSD) and phase histogram bandwidth (PHB), were assessed in post-stress and rest MPI images. ΔPSD (post-stress PSD - rest PSD) and ΔPHB (post-stress PHB - rest PHB) were calculated to measure stress-induced changes in LVMD. RESULTS: In all the groups, mean post-stress LVMD parameters were lower as compared to LVMD parameters at rest. Post-stress PSD was significantly lower than rest PSD in all groups. Similar trend was noted with PHB values also, but it was statistically significant in the normal and ischemia group only. Post-stress worsening of at least one of the LVMD parameters was noted in 28 patients and all these patients had perfusion abnormalities. But on subgroup analysis, no difference was found in proportion of patients showing post-stress worsening of LVMD between ischemia (13.6%), infarct (25%), and mixed (23.6%) groups. No significant correlation was found between ΔPSD/ΔPHB and ΔLVEF/SDS in any group. CONCLUSION: LV mechanical dyssynchrony parameters are smaller in post-exercise stress as compared to rest on Tl-201 MPI, regardless of perfusion pattern. Stress-induced worsening of LV dyssynchrony was observed only in patients with perfusion abnormalities, but this is not related to the type of perfusion abnormality.

Paced QRS duration predicts left ventricular function in patients with permanent pacemakers - One-year follow-up study using equilibrium radionuclide angiography (ERNA).

Permanent pacing, being non physiological, often results in ventricular dysfunction over time. Narrower paced QRS duration from pacing the right ventricular outflow tract septum, might result in relatively preserved ventricular function over long term follow up.

Detection of homing-in of stem cells labeled with technetium-99m hexamethylpropyleneamine oxime in infarcted myocardium after intracoronary injection.

Bone marrow stem cells having myogenic potential are promising candidates for various cell-based therapies for myocardial disease. We present here images showing homing of technetium-99m (Tc-99m) hexamethylpropyleneamine oxime (HMPAO) labeled stem cells in the infarcted myocardium from a pilot study conducted to radio-label part of the stem cells in patients enrolled in a stem cell clinical trial for recent myocardial infarction.

Effect of duration of fasting and diet on the myocardial uptake of F-18-2-fluoro-2-deoxyglucose (F-18 FDG) at rest.

CONTEXT: Patterns of myocardial fluoro-2-deoxyglucose (FDG) uptake with respect to duration of fasting and dietary modifications. AIM: We observed the effect of duration of fasting and diet on the myocardial uptake pattern of F-18 FDG in patients routinely referred for oncological evaluation and no previous history of Coronary Artery Disease (CAD). SETTINGS AND DESIGN: Prospective study. SUBJECTS AND METHODS: A total of 153 patients (M: 81, F: 72; mean age: 47 ± 15 years; mean blood glucose level (mBG) 105 ± 23 mg/dl) were randomly divided in three groups. Group A: 4-6 h fasting; Group B: Overnight fasting (12-14 h); Group C: Low carbohydrate and fat rich diet for 2 days coupled with overnight fasting prior to the positron emission tomography (PET) scan. FDG uptake was classified as following: 1) homogeneous uptake, 2) heterogeneous uptake, and 3) 'no uptake' in the left ventricular (LV) myocardium. FDG PET study was performed as standard protocol for oncological conditions. STATISTICAL ANALYSIS USED: Descriptive statistics, Chi-square test or Fisher's exact test, and Spearman's rank correlation tests were applied. RESULTS: We observed the 'no uptake' pattern in five (10%), 28 (55%), and 39 (77%), 'heterogeneous' pattern in 20 (39%), 14 (28%), and seven (14%), and 'homogeneous' pattern in 26 (51%), nine (18%), and five (10%) patients in Group A, B, and C, respectively. There was statistically significant difference of myocardial uptake pattern between group A and B (P < 0.0001), between group A and C (P < 0.0001), and between Group B and C (P = 0.023). The mBG was 102, 105, and 111 mg/dl in 'no uptake', heterogeneous, and homogeneous uptake pattern, respectively, (P = 0.103). Also, within each group the mBG was not related to the uptake pattern. CONCLUSION: Both restricted diet and duration of fasting play an important role in determining the pattern and suppression of myocardial F-18 FDG uptake. Overnight fasting and restricted diet together suppress myocardial FDG uptake more than overnight fasting alone, which suppresses uptake more than 4-h fasting.