Wolfgang Burchert

Fluorine-18 fluorodeoxyglucose positron emission tomography in thyroid cancer: results of a multicentre study

n=222) and the group with negative radioiodine scan (n=166), respectively. Specificity was 90% in the whole patient group. Sensitivity and specificity of WBS were 50% and 99%, respectively. When the results of FDG-PET and WBS were considered in combination, tumour tissue was missed in only 7%. Sensitivity and specificity of MIBI/Tl were 53% and 92%, respectively (n=117). We conclude that FDG-PET is a sensitive method in the follow-up of thyroid cancer which should be considered in all patients suffering from differentiated thyroid cancer with suspected recurrence and/or metastases, and particularly in those with elevated thyroglobulin values and negative WBS.

I-123-mIBG myocardial imaging for assessment of risk for a major cardiac event in heart failure patients: insights from a retrospective European multicenter study

PurposeSingle-center experiences have shown that myocardial meta-iodobenzylguanidine (mIBG) uptake has prognostic value in heart failure (HF) patients. To verify these observations using a rigorous clinical trial methodology, a retrospective review and prospective quantitative reanalysis was performed on a series of cardiac 123I-mIBG scans acquired during a 10-year period at six centers in Europe.Methods123I-mIBG scans obtained on 290 HF patients [(262 with left ventricular ejection fraction (LVEF) < 50%)] from 1993 to 2002 were reanalyzed using a standardized methodology to determine the heart-to-mediastinum ratio (H/M) on delayed planar images. All image results were verified by three independent reviewers. Major cardiac events [MCEs; cardiac death, cardiac transplant, potentially fatal arrhythmia (including implantable cardioverter-defibrillator discharge)] during 24-month follow-up were confirmed by an adjudication committee.ResultsMCEs occurred in 67 patients (26%): mean H/M ratio was 1.51 ± 0.30 for the MCE group and 1.97 ± 0.54 for the non-MCE group (p < 0.001). Two-year event-free survival using an optimum H/M ratio threshold of 1.75 was 62% for H/M ratio less than 1.75, 95% for H/M ratio greater than or equal to 1.75 (p < 0.0001). Logistic regression showed H/M ratio and LVEF as the only significant predictors of MCE. Using the lower and upper H/M quartiles of 1.45 and 2.17 as high- and very low-risk thresholds, 2-year event-free survival rates were 52% and 98%, respectively. Among patients with LVEF ≤ 35% and H/M ≥ 1.75 (n = 73), there were nine MCEs because of progressive HF and only one because of an arrhythmia.ConclusionApplication of a clinical trial methodology via the retrospective reanalysis of 123I-mIBG images confirms the previously reported prognostic value of this method in HF patients, including potential identification of a quantitative threshold for low risk for cardiac mortality and potentially fatal ventricular arrhythmias.

Synthesis and evaluation of a 18F-labelled recombinant annexin-V derivative, for identification and quantification of apoptotic cells with PET

In this report, we describe the synthesis of 4-[18F]-fluorobenzoyl-annexin V (4-[18F]FBA). In a four-step procedure, 4-[18F]FBA was synthesised with a microcomputer controlled, automated module within 90min. The radiochemical yield was in the range of 15-20% (corrected for decay) with a specific activity of more than 35GBq/micromol. The specific binding was confirmed by studies of 4-[18F]FBA with phosphatidylserine-containing liposomes. The biological activity of 4-[18F]FBA was verified by measuring its binding to Jurkat T-cell lymphoblasts after induction of apoptosis as compared to control cells without apoptosis. 4-[18F]FBA seems to be a suited tracer to measure apoptotic activity in vivo.

Coronary anomalies assessed by whole-heart isotropic 3D magnetic resonance imaging for cardiac morphology in congenital heart disease.

To determine the value of whole‐heart three‐dimensional magnetic resonance imaging (MRI) for coronary artery imaging in children/adolescents with congenital heart disease (CHD).

Left ventricular volumetry in healthy children and adolescents: comparison of two different real-time three-dimensional matrix transducers with cardiovascular magnetic resonance

AIMS To assess the accuracy of different hardware and software settings for left ventricular (LV) volume quantification in children using real-time three-dimensional echocardiography (RT3DE). METHODS AND RESULTS The impact of different matrix transducers (IE 33, X3-1 and VIVID 7, V3) and quantification software settings [TOMTEC; contour-finding activity (tCFA) values ranging from 30 to 70 U] on the accuracy of LV indices was tested in 24 healthy children/adolescents (median = 12.6 years) and 25 paediatric patients with Tetralogy-of-Fallot (TOF) (median = 7.3 years) with abnormally shaped ventricles. RT3DE was compared with cardiovascular magnetic resonance (CMR) volumetry as reference. Best agreement (Bland-Altman analysis) was achieved using a tCFA value of 30 U. Applying the V3 device, end-diastolic volume (EDV) and end-systolic volume (ESV) were underestimated by 14.8 +/- 10.6% (mean +/- SD) and 11.2 +/- 16.3%, respectively (r = 9.42, P < 0.001 and r = 0.937, P = 0.003); with the X3-1 system 24.2 +/- 11.0 and 14.6 +/- 15.2%, respectively (r = 0.951, P < 0.001 and r = 0.912, P = 0.001). Negligible differences <1% (P = n.s.) between both transducers were detected applying a tCFA value of 70 U but with significant underestimation (EDV: approximately 35%, P < 0.001; ESV: approximately 26%, P < 0.001) compared with CMR. EDV and ESV of TOF patients were underestimated by 3.2 +/- 15.4 and 8.1 +/- 22.6%, respectively. Intra- and interobserver variability was <4%. CONCLUSION In contrast to recommendations of the manufacturer, data sets from both RT3DE transducers showed acceptable agreement to CMR for volumetric parameters only for low tCFA. Fine-tuning of software settings is mandatory to improve accuracy.

Improved coronary vasodilatatory capacity by H.E.L.P. apheresis: comparing initial and chronic treatment.

Abstract:  Hypercholesterolemia impairs endothelial function and subsequently decreases coronary vasodilatatory capacity. We examined the quantitative effects of one single LDL apheresis on vasodilatatory capacity. Using N‐13 ammonia as a tracer for dynamic quantitative positron emission tomography (PET), mean myocardial perfusion measurements were carried out before and 20 h later after LDL apheresis, both under resting conditions and after pharmacological vasodilatation with dipyridamole. LDL apheresis was carried out using the heparin induced extracorporeal LDL precipitation (H.E.L.P.) procedure. We examined 47 patients (12 women and 35 men), with angiographically‐proven coronary artery disease. All of them suffered from hypercholesterolemia. Of the patients, 35 received a chronic weekly H.E.L.P. procedure (group A), while H.E.L.P. procedure treatment was started for the first time in 12 patients, who were subsequently enrolled in a chronic apheresis program (group B). H.E.L.P. apheresis was combined with cholesterol lowering drugs in all patients. Both groups underwent positron emission tomography twice (prior to LDL apheresis and 20 h later). In group A, LDL cholesterol levels decreased from 175 ± 50 mg/dL to 60 ± 21 mg/dL immediately after H.E.L.P. (77 ± 25 mg/dL before the second PET). Corresponding values for fibrinogen levels were 287 ± 75 mg/dL to 102 ± 29 mg/dL (155 ± 52 mg/dL), minimal coronary resistance dropped from 0.56 ± 0.20 to 0.44 ± 0.17 mm Hg × 100 g × min/mL (P < 0.0001). Plasma viscosity decreased by 7.8%. In group B, LDL cholesterol decreased from 187 ± 45 mg/dL to 75 ± 27 mg/dL (85 ± 29 mg/dL) and fibrinogen from 348 ± 65 mg/dL to 126 ± 38 mg/dL (168 ± 45 mg/dL). Minimal coronary resistance was reduced from 0.61 ± 0.23 to 0.53 ± 0.19 mm Hg × 100 g × min/mL (P < 0.01). Plasma viscosity was observed to decrease by 7.6%. The strong LDL drop in patients under chronic H.E.L.P. treatment has a significant impact on coronary vasodilatatory capacity within 20 h leading to an improved overall cardiac perfusion. Nearly the same effect can be seen in patients after their first H.E.L.P. treatment. 

Myocardial Fibrosis Is Associated with Biventricular Dysfunction in Patients with Hypertrophic Cardiomyopathy

Aims: To assess left (LV) and right ventricular (RV) function by two‐dimensional (2D) speckle tracking echocardiography and its relation to myocardial fibrosis in hypertrophic cardiomyopathy (HCM). Methods: We enrolled 50 HCM patients (30 male; 47.3 ± 9.9 years) in our study. Each patient received echocardiography with modern high‐end scanners. For speckle tracking analysis of LV and RV function the dedicated software was used. The presence of myocardial fibrosis was detected by cardiac magnetic resonance imaging (MRI). Results: For intraobserver variability of RV global longitudinal strain, we found a correlation of r = 0.89 (p < 0.001) with a minor bias of 4.9 ± 2.9%. On cardiac MRI 30 patients (60%) demonstrated late gadolinium‐enhancement (LGE) of the LV. Of these patients only 7% showed LGE of the RV. HCM patients with myocardial fibrosis had less global longitudinal LV strain in comparison to patients without myocardial fibrosis (−12.8 ± 2.2 vs −21.1 ± 2.6, P < 0.001), thicker interventricular septums (23.7 ± 4.0 vs 19.2 ± 5.1, P < 0.001), larger left atria (34.9 ± 7.1 vs 23.9 ± 5.1, P < 0.001), and impaired diastolic function (E/A‐ratio: 1.02 ± 0.22 vs 1.15 ± 0.18, P < 0.01). Comparable results were found for RV function. LV and RV strain correlated with r = 0.85 (p < 0.001). Conclusions: HCM is not only a disease of the LV. LGE in HCM is associated with both LV and RV dysfunction. Although RV LGE occurs only in a minority of patients with HCM and LV fibrosis, speckle tracking echocardiography is feasible for evaluating LV and RV dysfunction in these patients. (Echocardiography 2012;29:438‐444)

Use of positron emission tomography for the assessment of skeletal muscle glucose metabolism.

Positron emission tomography (PET) is a unique tool for studying regional skeletal muscle glucose metabolism and blood flow in vivo. The application of PET in the assessment of skeletal muscle glucose metabolism depends on recent improvements in instrumentation, data analysis, and production of (18)F-fluorodeoxyglucose (FDG) and (15)O water. The data presented support the validity of the (15)O water model to measure blood flow and the FDG model for the determination of glucose uptake and glucose kinetic constants (influx, efflux, and phosphorylation) in skeletal muscle. However, quantification of absolute glucose transport and backflux rates should be applied with caution because those calculations are based on unproven assumptions such as validity of the lumped constant for these individual processes and constancy of the free and accessible intracellular glucose pool. It is evident that quantification of glucose fluxes using the triple tracer technology generates conflicting data that violate assumptions inherent in triple tracer or PET modeling. Further FDG-PET studies will have to solve those problems to provide more insight into the regulatory processes of glucose transport and phosphorylation of different insulin-resistant disease states. Promising new areas of PET research will include not only detailed study of glucose kinetics but also the measurement of muscle protein synthesis in vivo, which is of interest in a variety of conditions.

Myocardial perfusion scintigraphy in Germany in 2009: utilization and state of the practice

PurposeSince 2006, the working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine, in cooperation with the working group Nuclear Cardiology of the German Cardiac Society, has been surveying the utilization and technical realization of myocardial perfusion scintigraphy (MPS) in Germany. This paper presents the results of the reporting year 2009.MethodsA total of 291 centres participated in the inquiry, including 179 private practices (PP), 86 hospitals (HO) and 26 university hospitals (UH).ResultsMPS of 98,103 patients were reported. The MPS numbers per million population (pmp) were estimated at 2,360; 76% of the MPS were performed in PP, 17% in HO and 7% in UH. The ratio of MPS to coronary angiography to revascularization was 0.5 to 2.3 to 1. Data from 134 centres which participated in the surveys from 2005 to 2009 showed a decrease in MPS utilization of 2.2%. Nearly half of the MPS were requested by ambulatory care cardiologists. Of all MPS studies, 89% were conducted with 99mTc perfusion tracers. Ergometry was the preferred stress test (69%). Adenosine was used in 16%, adenosine + exercise in 7%, dipyridamole in 3%, dipyridamole + exercise in 5% and dobutamine in <1%. Gated single proton emission computed tomography (SPECT) acquisition was performed in 56% of all rest MPS and in 56% of all stress MPS. Both rest and stress MPS were ECG gated in 41%. Only 33% of the centres always performed a quantification of the perfusion studies, whereas 51% did not apply any quantification; 4% of the MPS studies were corrected for attenuation, and 17 centres used transmission sources of 12 CT-based systems.ConclusionA scan activity of 2,380 MPS pmp is in the upper third of the European range. The ratios to coronary angiography and to revascularization suggest that angiography dominates diagnosis and management of coronary artery disease (CAD). The clinical and technical realizations reveal that the predominant goals of further trainings to optimize MPS are in the field of gated SPECT and quantitative perfusion SPECT.

[Myocardial perfusion scintigraphy 2008 in Germany - results of the fourth query].

AIM The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine in cooperation with the working group Nuclear Cardiology of the German Cardiac Society herewith present the results of the 4th survey on myocardial perfusion scintigraphy (MPS) of the year 2008. METHOD 310 questionnaires (191 private practices (PP), 93 hospitals (HO), 31 university hospitals (UH)) were evaluated. RESULTS MPS of 98947 patients were reported. 15% of them were younger than 50 y, 57% between 50 and 70 y and 28% older than 70 y. 88% [2007: 83%] of all were studied with Tc-99m perfusion tracers. The patient radiation exposure of a stress and rest protocol considering German standard recommended doses was 8.5 mSv, of a stress-only protocol 1.9 mSv. 77% [2007: 76%] of the MPS were performed in PP, 15% [2007: 15%] in HO and 8% [2007: 9%] in UH. From 2005 to 2008 there was a mild increase in the MPS numbers by 1.2% (PP +7.1%, HO -5.5%, UH -31.4%). The type of stress was pharmacological in 30% [2007: 27%]; 68% adenosine (of these 22% with exercise), 29% dipyridamole (of these 64% with exercise), and <1% dobutamine. Gated SPECT was performed in 46% [2007: 47%] of all rest and in 42% [2007: 44%] of all stress MPS. 62% [2007: 61%] of all institutions did not use perfusion scores. CONCLUSION The MPS numbers from 2005 to 2008 in Germany can be regarded as stable. However, there are considerable shifts from HO and UH to PP. The well known potential of MPS considering risk stratification and functional analysis has not been tapped so far. Both gated SPECT and a quantitative perfusion analysis should be performed routinely in every patient.