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Knowledge of coronary artery calcium score (CACS) influences the interpretation of myocardial perfusion imaging (MPI) with SPECT; however, the impact on PET interpretation remains unclear. We compared the added value of CACS to reporting MPI using SPECT vs PET. We retrospectively included 412 patients. 206 patients who underwent Rb-82 PET were propensity-based matched to a cohort of 4018 patients who underwent cadmium–zinc–telluride SPECT MPI to obtain a comparable group of 206 SPECT patients. Next, we created four image sets: SPECT MPI-only, PET-only, SPECT + CACS, and PET + CACS. Two physicians interpreted the 824 images as normal, equivocal, or abnormal for ischemia or irreversible defects. Additionally, event rates were compared between PET and SPECT groups during 30-month follow-up. PET yielded more scans interpreted as normal than SPECT (88% vs 80%, respectively, P = 0.015). Adding CACS to SPECT increased the percentage of normal scans to 86% (P = 0.014), whereas this effect was absent for PET (90%, P = 0.77). Annualized event rates for images interpreted as normal did not differ and varied between 0.7 and 2.0% (P > 0.084). Adding CACS correctly increased the percentage of normal scans for SPECT MPI but not for PET, possibly limiting the effect of adding CACS to reporting PET.

Funding Acknowledgements Type of funding sources: None. Background and purpose Myocardial blood flow (MBF) measurements using PET are increasingly used to guide the management of patients with (suspected) coronary artery disease (CAD). Day-to-day variability of these measurements is poor with a 21% standard deviation or 40% 95%-confidence interval [Reference: JACC Cardiovasc Imaging, 2017;10(5):565]. This limits clinical applicability in diagnosis, risk stratification and follow-up as these all depend on comparison of flow values with fixed cut-off values. We expect that reproducibility can be improved by combining flow measurements with the variation of flow values within the myocardium. As entropy is a measure of variability of the associated distribution, we compared the reproducibility of an entropy-based flow parameter with that of conventional myocardial flow reserve (MFR) measurements. Methods We performed a study using intra-individual comparison in 24 patients who underwent rest and regadenoson-induced stress myocardial perfusion imaging using Rubidium-82 on two different PET systems (PET1: Discovery 690, GE Healthcare, and PET2: Vereos, Philips Healthcare) within 3 weeks. MBF for both rest and stress was calculated using Lortie’s one-tissue compartment model (Corridor4DM, INVIA). MFR (ratio of MBF stress/rest) was determined for the myocardial as a whole (MFRglobal), for the three vascular territories: LAD, LCX and RCA (MFRregional) and for the 17 segments. Next, we calculated Shannon’s entropy to measure the variation of the 17 MFR segmental values. We multiplied Shannon’s entropy by the mean of the MFR segmental values resulting in an entropy-based MFR (MFRentropy). For each patient MFRglobal, MFRregional and MRFentropy were compared between both PET systems. For each of the three parameters the test-retest precision was calculated as the SD of the relative difference between measurements. Results The mean difference in MFR measurements between both cameras did not differ from zero (p > 0.05). Mean values for PET1 were MFRglobal = 2.4, MFRregional = 2.4 (LAD), 2.4 (LCX) and 2.5 (RCA), and MFRentropy = 2.4. For PET2 we found MFRglobal = 2.5, MFRregional = 2.5 (LAD), 2.4 (LCX) and 2.6 (RCA), and MFRentropy = 2.5. Test-retest precision was lower for MFRentropy with 11% compared to that of MFRglobal (21%), MFRregional LAD (22%), MFRregional LCX (23%) and MFRregional RCA (24%) (p Conclusion The reproducibility of myocardial flow reserve measurements using Rubidium-82 PET improved by a factor of 2 when an entropy-based flow parameter instead of global or regional MFR parameters is used. This entropy-based flow-parameter may be used to better discriminate ischemia from non-ischemia and may therefore improve CAD management.

Funding Acknowledgements Type of funding sources: None. Background Although it is well known that coronary artery calcium score (CACS) adds value to reporting myocardial perfusion imaging (MPI) SPECT, its added value to reporting PET MPI is not clear. Purpose Hence, our aim was determine the value of adding CACS in the assessment of PET MPI and SPECT MPI and compare the value between both modalities in a low-risk population. Methods We retrospectively included 412 patients, half of them underwent SPECT with CACS and half underwent Rubidium-82 PET with CACS. We created comparable groups using propensity matching, where the PET group was 1:1 matched to a comparable SPECT group, obtained from a large cohort of 4018. Next, we created two types of image sets for the 412 included patients: MPI-only and MPI + CACS. Two experienced physicians interpreted the 824 images as normal, equivocal or abnormal for ischemia or irreversible defects and were blinded for the used modality. In addition, annualized event rates, defined as the occurrence of all-cause death, non-fatal myocardial infarction or revascularization therapy (PCI or CABG), were compared between the PET and SPECT groups using a follow-up period of 30 months. Results The percentage of scans interpreted as normal was 8% higher with PET-only than with SPECT-only (89 vs 80%, respectively, p = 0.014). Adding CACS to SPECT increased the percentage of scans interpreted as normal from 80% to 86% (p = 0.014), whereas this effect was absent for PET (p = 0.77). Adding CACS reduced the frequency of equivocal scans from 12% and 6% to 0% for both SPECT and PET, respectively. Furthermore, adding CACS resulted in 5% more abnormal interpreted scans for both PET (4.9 to 10%, p = 0.003) and SPECT (8.7 to 14%, p = 0.04). The annualized event rate was 2.7% for the SPECT and 3.5% for the PET group (p = 0.58). The annualized event rates for images interpreted as normal were comparable between all four types of image sets and varied between 0.7-2.0% (p > 0.084). The annualized event rate for equivocal and abnormal scans was higher for PET-only (23%) compared to SPECT-only (4.8%, p Conclusion Adding CACS increases the percentage of scans interpreted as normal for SPECT MPI while the event rate remained unchanged. Adding CACS to PET did not influence the percentage of scans interpreted as normal, limiting the effect of adding CACS to PET in a low-risk population.

Funding Acknowledgements Type of funding sources: None. Introduction The combination of myocardial blood flow (MBF) measurements using Rubidium-82 (Rb-82) PET and visual assessment of the PET images is increasingly used due to its high diagnostic and prognostic value. Typically, flow measurements are calculated and used for the myocardium as a whole (global). However, small regional flow deficits may go unnoticed when only looking at global flow values. Purpose To compare the diagnostic value of regional and global myocardial flow measurements using Rb-82 PET in the detection of obstructive CAD. Methods We retrospectively included 1034 patients with no history of coronary artery disease (CAD) referred for rest and regadenoson-induced stress Rb-82 PET/CT. MBFs were calculated using Lortie’s one-tissue compartment model. Myocardial flow reserve (MFR) was calculated as the ratio of MBF during stress and rest. Regional flow was determined per vessel and per segment. Vessel MFR was defined as the lowest flow reserve of LAD, LCX and RCA territories and segmental MFR as the lowest flow reserve in all 17 segments. Follow-up data were obtained from medical records. Patients were classified to have obstructive CAD if follow-up included a positive invasive coronary angiography (ICA), percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) or all cause death. Receiver-operating characteristic (ROC) analyses were constructed to compare the diagnostic value of global and regional flow values. Results Follow-up was obtained in all 1034 patients and the median follow-up time was 2.1 years. Myocardial flow reserve values were significantly lower (p Conclusion The diagnostic value improved with the use of regional MFR instead of global MFR measurements in the detection of obstructive CAD. Therefore, it seems that visual assessment of PET images can best be combined with regional flow measurements either on a per vessel or a per segment basis in Rubidium-82 PET myocardial perfusion imaging.

Aim During invasive fractional flow reserve (FFR) adenosine and nitrates are used to obtain maximal hyperemia. Severe coronary artery calcification (CAC) is associated with impaired vasodilation. We investigated the hyperemic response during FFR in vessels with severe versus mild CAC. Methods and results We retrospectively selected 236 patients who underwent both CAC scoring and invasive FFR. FFR was performed in 304 vessels with intermediate stenoses. Delta (Δ) FFR, the pressure gradient before the administration of adenosine minus FFR after the administration of adenosine, was used to investigate the hyperemic response. Mean age of the total population was 65 ± 10 years, 65% was male. Median CAC score was 510 (range 0 to 6141). Mean pressure gradient before the administration of adenosine was comparable in vessels with severe versus mild CAC. FFR was more often ≤0.80 in vessels with severe CAC (p = 0.045). Patients with a large Δ FFR were younger (p = 0.05). There was no association between Δ FFR and severity of calcifications. Regression analysis did not demonstrate an association between CAC score and the hyperemic response (p = 0.49). Conclusion We did not find an association between the severity of CAC and the hyperemic response during invasive FFR.

AIM Integration of endomyocardial biopsy (EMB) in the diagnostic workup of cardiac sarcoidosis (CS) is under-recognized in current clinical practice, since capturing focal granulomas is challenging. Our aim was to describe our experience with electro-anatomic mapping (EAM)-guided EMB and provide a comprehensive review of the literature. METHODS AND RESULTS Five patients (age 49.4 ± 11.4) with suspected CS underwent EAM-guided EMB in Isala Heart Center (Zwolle, the Netherlands) between 2017 and 2019. In all patients, a 3D bipolar voltage map (

Background: SPECT Myocardial perfusion imaging (MPI) is associated with a relatively high radiation burden and decreasing image quality in heavy patients. Patient-specific low-activity protocols (PLAPs) are suggested but follow-up data is lacking. Our aim was to compare the use of a standard fixed-activity protocol (FAP) with a PLAP in cadmium zinc telluride (CZT)-SPECT MPI. Methods: We retrospectively included 1255 consecutive patients who underwent CZT-SPECT stress-optional rest MPI. 668 Patients were scanned using FAP (370 MBq) and 587 patients using PLAP (2.25 MBq·kg−1). Percentage of scans interpreted as normal, radiation dose, and 1-year follow-up including hard event rates (all-cause death or non-fatal myocardial infarction) were collected and compared. Results: The percentage of scans interpreted as normal was 67% in FAP and 70% in PLAP groups (P = .29). The annualized hard event rates in these patients were 1.0% in the FAP and 0.9% in the PLAP group (P = .86). However, the mean radiation dose decreased by 23% for stress-only and by 15% to 2.6 mSv for stress-optional rest MPI after introduction of the PLAP (p

Background: Regadenoson-induced stress causes a repositioning of the heart, myocardial creep, in half of the patients undergoing Rubidium-82 (Rb-82) positron emission tomography (PET). As a result, misalignment of dynamic PET and computer tomography (CT) may occur, possibly affecting CT-based attenuation correction (AC) and thereby PET-based myocardial blood flow (MBF) quantification. Our aim was to determine the need for frame-wise PET-CT AC to obtain reliable MBF measurements. Methods: 31 Out of 64 consecutive patients had myocardial creep during regadenoson-induced stress Rb-82 PET-CT and were included. Prior to PET image reconstruction, we applied two AC methods; single PET-CT alignment and frame-wise alignment in which PET time-frames with myocardial creep were individually co-registered with CT. The PET-CT misalignment was then quantified and MBFs for the three vascular territories and whole myocardium were calculated and compared between both methods. Results: The magnitude of misalignment due to myocardial creep was 13.8 ± 4.5 mm in caudal-cranial direction, 1.8 ± 2.1 mm in medial-lateral and 2.5 ± 1.8 mm in anterior-posterior direction. Frame-wise PET-CT registration did not result in different MBF measurements (P ≥.07) and the magnitude of misalignment and MBF differences did not correlate (P ≥.58). Conclusion: There is no need for frame-wise AC in dynamic Rb-82 PET for MBF quantification. Single alignment seems sufficient in patients with myocardial creep.

Introduction Almost 25% of women diagnosed with breast cancer have a non-palpable tumor. In breast-conserving therapy, it is important to have oncologic clear margins while excising minimal healthy tissue with good cosmetic outcome. The three most used techniques for non-palpable tumor localization pre-operative are radioactive seed localization (RSL), wire-guided localization (WGL), and radio-guided occult lesion localization (ROLL). Besides the advantage of tumor localization, each technique has its own disadvantages. When RSL is used, the major concern is safe handling of the seeds because of the used radioactive material. In case of WGL, the ideal skin incision and accurate positioning of the wire do not always match. The tip of the wire is non-palpable during surgery, which increases the risk of positive margins and increases the risk of enlarging resection volume resulting in poor cosmetic outcome. Moreover, the wire can get displaced or can be transsected during surgery. Disadvantages of ROLL include diffuse spread of the radioactive tracer in the breast tissue, which can result in higher excision volumes and problems with the concurrent sentinel node procedure. Thus far, no study has been performed comparing these three techniques. Therefore, this study analyzed the outcomes of RSL, WGL, and ROLL in non-palpable breast cancer in a single institution. Methods Women diagnosed with ductal carcinoma in situ or non-palpable invasive breast carcinoma (stadium I or II) and were operated from January 2011 to December 2013 were retrospectively included in this study (N=278). In all included women in this study, RSL (n=71), WGL (n=78) or ROLL (n=132) was performed for intra-operative tumour localization. Outcome measures were weight of the resected specimen, oncological margins, re-excision and recurrence of disease. Results In total 278 lumpectomies were performed in 272 patients. Mean resection volumes were not significant higher in RSL (mean 97.8 cm3), compared to WGL (mean 80.9 cm3) and ROLL (mean 84.8cm3). RSL was associated with significant less tumor-positive margins (n=55, 96.5%) compared to the WGL (n=55, 73.3%) and ROLL (n=111, 84.1%). Also, RSL was associated with significant lower re-excision rates (n=1, 1.4%) as compared to WGL (n=12, 15.4%) and ROLL (n=14, 10.6%). In only one patient with ROLL, recurrence of disease was seen. The median follow-up of all patients was 27 months (9 – 44). Conclusion This study revealed that RSL is an effective technique for excision of non-palpable breast cancer and is associated with fewer tumor-positive margins and therefore lower re-excision rates. Citation Format: Theunissen CIJM, Noorda EM, Rust EAZ, Bandel C, Ooster- van den Berg JGv, Edens MA, Jager PL, Francken AB. Radioactive seed localization in non-palpable breast cancer compared to wire-guided localization and radio-guided occult lesion localization: Results of a comparative study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-13-04.

Guidelines propose different rest–stress activity ratios (RSAR) for one-day stress-first SPECT myocardial perfusion imaging (MPI), but evidence is limited. Our aim was to determine and validate the minimal RSAR resulting in the same diagnostic outcome in one-day stress-first SPECT MPI. Forty-seven patients referred for rest after stress CZT-SPECT/CT MPI were prospectively included. Rest acquisitions were performed 3 h after stress. In addition to the stress and rest acquisitions, the first 22 patients underwent an additional acquisition prior to the rest injection to determine the remaining stress activity. Next, we simulated six RSARs varying from 1.0 to 3.5 in both patients and a phantom and compared the images to those using the reference RSAR of 4.0. Differences in summed difference score (SDS) >2 or ischemic defect interpretation were considered to significantly influence diagnostic outcome. After deriving the minimal RSAR, it was validated in 25 additional patients by comparing it to a RSAR of 4.0. After 3 h only 26% of the stress activity was still present in the myocardium. SDS differences >2 were found in one (4%) patient using RSAR of 3.5, 2.5 and 2.0, in three (12%) using 1.5 and in five (20%) using SRAR of 1.0. These results were consistent with the phantom study showing SDS differences >2 for RSARs ≤1.5 and with the visual interpretation which showed an increased number of deviating scans for RSAR 1.0. Validating the RSAR of 2.0 resulted in a different SDS in one patient (SDS of 30 versus 11). Moreover, two scans were interpreted as ischemic instead of normal when using RSAR 2.0 and in two other scans the opposite was the case. A RSAR of 2.0 in one-day stress-first MPI SPECT seems sufficient to obtain accurate diagnostic outcomes and is therefore recommended to reduce radiation exposure.

Background: Repositioning of the heart during myocardial perfusion imaging (MPI) using Rubidium-82 (Rb-82) PET may occur when using regadenoson. Our aim was to determine the prevalence and the effect of correcting for this myocardial creep on myocardial blood flow (MBF) quantification. Methods: We retrospectively included 119 consecutive patients who underwent dynamic rest- and regadenoson-induced stress MPI using Rb-82 PET. The presence of myocardial creep was visually assessed in the dynamic stress PET series by identifying differences between the automatically drawn myocardium contour and the activity. Uncorrected and corrected stress MBFs were compared for the three vascular territories (LAD, LCX, and RCA) and for the whole myocardium. Results: Myocardial creep was observed in 52% of the patients during stress. Mean MBF values decreased after correction in the RCA from 4.0 to 2.7 mL/min/g (P < 0.001), in the whole myocardium from 2.7 to 2.6 mL/min/g (P = 0.01), and increased in the LAD from 2.5 to 2.6 mL/min/g (P = 0.03) and remained comparable in the LCX (P = 0.3). Conclusions: Myocardial creep is a frequent phenomenon when performing regadenoson-induced stress Rb-82 PET and has a significant impact on MBF values, especially in the RCA territory. As this may hamper diagnostic accuracy, myocardial creep correction seems necessary for reliable quantification.

Aims Obtaining optimal pulmonary vein (PV) occlusion with the endoscopic laser balloon ablation system (EAS) can be difficult, hypothetically influenced by PV geometry. The aim of this study was to determine the impact of PV orientation on atrial fibrillation (AF)-free survival after PV isolation (PVI) using the EAS. Methods and results Forty-three patients undergoing a single EAS PVI were included. Left atrial electrocardiogram -triggered computed tomography was performed in all patients prior to PVI. Of all four PVs, the orientation at the insertion in the left atrium was measured in both the transverse and frontal plane and assigned to one of the four orientation groups: ventral-caudal, dorsal-caudal, ventral-cranial, and dorsal-cranial. Mean age was 56 years; 86% had paroxysmal AF. Overall, AF-free survival after a median follow-up of 18.2 months was 51.2%. AF-free survival varied between 21 and 88% depending on left upper PV orientation ( P = 0.045). Furthermore, AF-free survival varied between 21 and 86% depending on left lower PV orientation ( P = 0.010) and AF-free survival varied between 29 and 88% depending on right lower PV orientation ( P = 0.053). No association was found between right upper PV orientation and AF-free survival after EAS PVI ( P = 0.794). In multivariate analysis, only left lower PV orientation was associated with AF-free survival [hazards ratio (HR) 10.4, P = 0.019]. Conclusion PV orientation is associated with AF-free survival after EAS PVI. PV orientation assessment may be useful for selecting the most suitable patients for EAS PVI.

Due to the typesetter not carrying out the author’s corrections at proof stage, there are two errors in the published article: where “mL × min × g” appears, it should be “mL/min/g”. One error is in the Figure 3 caption, and one error is in the second sentence under the heading “MBF Quantification”. The original article has been corrected.

Patients with ischemic cardiomyopathy (ICM) are at risk for ventricular arrhythmias and are protected by an implantable cardioverter defibrillator (ICD). Visualization of cardiac sympathetic innervation may play an additional role to left ventricular ejection fraction (LVEF) in identifying those patients who will benefit from ICD therapy. The purpose of this study was to detect the role of sympathetic denervation in the genesis of ventricular arrhythmias in ICM patients.Twenty patients with ICM and LVEF30% were included in this pilot study. Included patients were equally stratified into two groups: no history of arrhythmias (group A) and recurrent arrhythmias (group B). All patients underwent cardiac sympathetic denervation (using carbon-11 labelled meta-hydroxy-ephedrine ([11C]-mHED)), myocardial ischemia and viability detection. Patients were followed up to one year after the imaging studies.Mean age was 63±7.5 years. Mean global retention of [11C]-mHED was 0.055±0,012 min-1, and was not different between the two patient groups: 0.056±0.011 min-1 vs. 0.054±0.013 min-1 for group A vs. group B, respectively. During follow-up, seven patients developed ventricular arrhythmias, and four patients died. No difference in [11C]-mHED retention was found between patients with and without ventricular arrhythmia during follow-up. However, size of denervated area was larger in patients who died during follow-up: 10±1 segments vs. 6±2 segments, P=0.002.Cardiac sympathetic innervation is impaired in patients with ischemic cardiomyopathy. All-cause mortality occurred in those patients with large areas of [11C]-mHED defect.

Target volume definition in modern radiotherapy is based on planning computed tomography (CT). So far, 18-fluorodeoxyglucose positron emission tomography (FDG-PET) has not been included in planning modality in volume definition of esophageal cancer. This study evaluates fusion of FDG-PET and CT in patients with esophageal cancer in terms of geographic misses and inter-observer variability in volume definition. In 28 esophageal cancer patients, gross, clinical and planning tumor volumes (GTV; CTV; PTV) were defined on planning CT by three radiation oncologists. After software-based emission tomography and computed tomography (PET/CT) fusion, tumor delineations were redefined by the same radiation-oncologists. Concordance indexes (CCI's) for CT and PET/CT based GTV, CTV and PTV were calculated for each pair of observers. Incorporation of PET/CT modified tumor delineation in 17/28 subjects (61%) in cranial and/or caudal direction. Mean concordance indexes for CT-based CTV and PTV were 72 (55-86)% and 77 (61-88)%, respectively, vs. 72 (47-99)% and 76 (54-87)% for PET/CT-based CTV and PTV. Paired analyses showed no significant difference in CCI between CT and PET/CT. Combining FDG-PET and CT may improve target volume definition with less geographic misses, but without significant effects on inter-observer variability in esophageal cancer.

Summary Vertebral Fracture Analysis enables the detection of vertebral fractures in the same session as bone mineral density testing. Using this method in 2,424 patients, we found unknown vertebral fractures in approximately one out of each six patients with significant impact on management. Introduction The presence of osteoporotic vertebral fractures (VF) is an important risk factor for all future fractures independent of BMD. Yet, determination of the VF status has not become standard practice. Vertebral Fracture Assessment (VFA) is a new feature available on modern densitometers. In this study we aimed to determine the prevalence of VF using VFA in all patients referred for BMD testing in a university medical center and to evaluate its added clinical value. Methods Prospective diagnostic evaluation study in 2,500 consecutive patients referred for BMD. Patients underwent VFA in supine position after BMD testing. Questionnaires were used to assess perceived added value of VFA. Results In 2,424 patients (1,573 women), results were evaluable. In 541 patients (22%), VFA detected a prevalent VF that was unknown in 69%. In women, the prevalence was 20% versus 27% found in men (p

Background The coronary calcium score (CCS) provides independent diagnostic and prognostic information on top of myocardial perfusion imaging (MPI) in patients suspected for coronary artery disease, but requires an additional computed tomography (CT) scan. Objective We investigated the accuracy and inter-reader reproducibility of visual estimation of the CCS on the CT used for attenuation correction. Methods 250 patients undergoing single photon emission computed tomography MPI and Agatston CCS were included. The CCS was also visually estimated on the CT for attenuation correction by two separate readers blinded to the Agatston CCS, and was categorized into a six-point scale (0, 1–10, 11–100, 101–400, 401–1000 and > 1000). Results The median Agatston CCS was 82 [25th–75th percentile: 0-562], with a range from 0 to 7287. Of the visually estimated CCS, 60% (reader 1) and 65% (reader 2) were classified correctly into the 6 categories. 93% (reader 1) and 88% (reader 2) of the visually estimated CCS did not vary by more than one category from the Agatston CCS. The intraclass correlation coefficient for agreement between the Agatston CCS and the visually estimated CCS was 0.95 for reader 1 and 0.94 for reader 2. The intraclass correlation coefficient for inter-reader reproducibility of the visually estimated CCS was 0.96. Conclusion The CCS can be accurately estimated on the CT for attenuation correction, as high agreement is demonstrated with the Agatston CCS and inter-reader reproducibility is excellent. If no traditional Agatston CCS is performed, the degree of atherosclerosis should be assessed by means of estimating CCS on the CT for attenuation correction.

Background Previous studies reported on the impact of pulmonary vein orientation on pulmonary vein isolation (PVI) outcome in atrial fibrillation patients undergoing laser balloon PVI and point-by-point radiofrequency ablation. Objective Demonstrate the association between pulmonary vein orientation and PVI outcome after multi-electrode radiofrequency ablation. Methods 120 patients undergoing PVI with a circular MER catheter were included. A left atrial ECG-triggered CT was performed in all patients prior to PVI. The orientation of all pulmonary veins at the insertion into the left atrium was measured in the axial and coronal planes. pulmonary veins were classified as having a ventral/dorsal and caudal/cranial orientation depending on the pulmonary vein trunk angle as compared to the median angle. Results Mean age was 56 years, arrhythmia-free survival after a median follow-up of 20 months was 54.2%. Left upper pulmonary vein orientation within the coronal plane was associated with arrhythmia-free survival, ranging from 58% with a cranial pulmonary vein orientation to 21% with a caudal orientation (p = 0.003). Similarly, arrhythmia-free survival was 50% in patients with a caudal orientation and 33% in patients with a cranial orientation of the left lower pulmonary vein in the coronal plane (p = 0.036). Pulmonary vein orientation in the axial plane and orientation of the right-sided pulmonary veins were not associated with arrhythmia-free survival. Multivariable analysis showed an independent association between both left upper (hazard ratio 2.8, p = 0.001) and left lower (hazard ratio 0.490, p = 0.034) pulmonary vein orientation and arrhythmia-free survival. Conclusion In MER ablation, orientation of the left upper and caudalpulmonary veins in the coronal plane were independently associated with arrhythmia-free survival after multi-electrode PVI.

Sentinel node detection in patients with breast cancer is routinely performed in our department. Images frequently show star-shaped activity at the site of injection caused by septum penetration. These star-shaped artifacts could possibly impair visualization of nearby sentinel nodes. The aim of this study was to determine whether sentinel node detection in patients with breast cancer can be improved using a medium-energy all-purpose (ME) collimator instead of a low-energy all-purpose (LEAP) collimator. For this purpose, 15 patients were studied and a phantom study was performed. The LEAP collimator was used for a dynamic study immediately after injection, and both the LEAP and the ME collimators were used for static studies. A total of 20 sentinel nodes were found with both collimators. All sentinel nodes were found in the axilla. To separate sentinel nodes from the injection site, the ME collimator gave the best results in 4 of 15 patients, but only within the first hour after injection. To separate 2 nearby sentinel nodes from each other, the LEAP collimator gave the best results in 3 of 15 patients. Our conclusion is that the LEAP collimator gave better results than the ME collimator as a result of the better resolution and the higher sensitivity. Use of the ME collimator did not improve sentinel node detection.

Background: In comparison with planar imaging gated blood-pool single photon emission computed tomography (GBPS) has the advantage of separating left and right ventricle. The purpose of this investigation was to evaluate the right ventricular ejection fraction (RVEF) calculations by GBPS software (‘NuSMUGA™’, Northwestern University, Chicago, IL) in comparison to first-pass radionuclide angiography (FPRNA). Methods: In 22 consecutive patients FPRNA and GBPS acquisition was performed. GBPS RVEF calculations were manually and automatically performed, using all gated short-axis-slices of the right ventricle. Results: Automatic RVEF assessed by GBPS did not correlate with conventional FPRNA (r = 0.40, p = 0.065). Mean FPRNA RVEF was 55 ± 10% and mean GBPS automatic RVEF was 32 ± 8%. Also manual GBPS RVEF did not correlate with conventional FPRNA (r = 0.41, p = 0.055). Mean RVEF measurement by manual GBPS was 33 ± 8%. Manual GBPS RVEF values correlated well with automatically determined GBPS RVEF values (r = 0.96, p < 0.0001). Conclusion: Automatic and manual values RVEF values assessed by GBPS did not correlate with conventional FPRNA values. FPRNA and GBPS calculations cannot be considered to be equivalent. Therefore the NuSMUGA program cannot be used to calculate RVEF.

Planar gated blood-pool imaging (GBPI) is a standard method for non-invasive assessment of left ventricular (LV) function. Gated blood-pool single photon emission computed tomographic (GBPS) data acquisition can be accomplished in the same time as GBPI, with the benefit of enabling visualization of all cardiac chambers simultaneously. The purpose of this investigation was to evaluate the degree to which automated and manual LVEF calculations agree with one another and with conventional GBPI LVEF measurements. GBPI studies were performed in 22 consecutive, unselected patients, followed by GBPS data acquisition. GBPS left ventricular ejection fraction (LVEF) calculations were performed by available software (NuSMUGA, Northwestern University, Chicago, IL) automatically and manually, using all LV gated short axis slices. Automatic LVEF assessed by GBPS correlated well with conventional planar GBPI (r = 0.88, P

Background: Diagnosis of active pulmonary and paranasal involvement in patients with Wegener’s granulomatosis (WG) can be difficult. The diagnostic value of gallium-67 scintigraphy in WG is unclear. Objective: To evaluate the added diagnostic value of gallium-67 scintigraphy in patients with WG with suspected granulomatous inflammation in the paranasal and chest regions. Methods: Retrospectively, the diagnostic contribution of chest and head planar gallium scans in 40 episodes of suspected vasculitis disease activity in 28 patients with WG was evaluated. Scans were grouped into normal or increased uptake for each region. Histological proof or response to treatment was the “gold standard” for the presence of WG activity. Results: WG activity was confirmed in 8 (20%) episodes, with pulmonary locations in three, paranasal in four, and both in one (n=7 patients); all these gallium scans showed increased gallium uptake (sensitivity 100%). Gallium scans were negative for the pulmonary area in 23/36 scans (specificity 64%), and negative for paranasal activity in 13/16 scans (specificity 81%) in episodes without WG activity. Positive predictive value of WG activity for lungs and paranasal region was 24% and 63%, respectively, negative predictive value was 100% for both regions. False positive findings were caused by bacterial or viral infections. Conclusion: Gallium scans are clinically helpful as a negative scan virtually excludes active WG. Gallium scintigraphy of chest and nasal region has a high sensitivity for the detection of disease activity in WG. However, because of positive scans in cases of bacterial or viral infections, specificity was lower.

Zowel [18F]-fluoromethylcholine (FCH) PET/CT als diffusiegewogen (DW) MRI wordt toegepast bij de lymfeklierstadiering bij prostaatcarcinoom.

A 5-week-old male infant with complete situs inversus and suspected asplenia underwent Tc-99m sulfur colloid and Tc-99m heat-denatured red blood cell (RBC) imaging to evaluate possible spleen function. The heat-denatured Tc-99m-labeled RBC scan revealed intense uptake in the normal-shaped right-side spleen, whereas the Tc-99m sulfur colloid scan showed only slight uptake in the reticuloendothelial system (RES). Therefore, the patient received antipneumococcal vaccination and antibiotic prophylaxis to prevent infections in the future.

20504 Background: Non-islet cell tumor induced hypoglycemia (NICTH) has been reported anecdotically in patients with a GIST and is associated with increased plasma levels of ‘big’-IGF-II, a high molecular weight form of IGF-II. The role of IGF-II in GIST is unknown. In non- GIST cancer, it has been suggested to be an autocrine growth factor, mainly acting by its major growth promoting receptors IGF-1 receptor (IGF- 1R) and the isoform A of the insulin receptor (IR). We investigated the clinical and biological relevance of (‘big’-)IGF-II in GIST. Methods: Plasma levels of ‘big’-IGF-II, and their relationship with disease status and NICTH, were determined in 25 consecutive GIST patients treated with imatinib (n=24) or sunitinib (n=1). Plasma samples were collected prior to, 1 week, and median 5 months after start of treatment. The levels of ‘big’-IGF-II were measured by specific radioimmunoassay (RIA). Results were compared with those obtained from healthy subjects and expressed as standard deviation scores (SDS). Paraffin-embedded GISTs (n=69) were analyzed for IGF-II, IGF-1R and IR expression by RNA in situ hybridization and immunohistochemistry (IHC). IGF-II secretion by the GIST882 cell line was analyzed by ELISA and western blotting. Results: Before treatment and/or during follow-up, 4 of 25 patients (16%) showed increased (i.e. SDS >2.0) plasma levels of ‘big’-IGF-II. Three of them developed NICTH. Patients with metastatic disease, high serum LDH, or total tumor size >12 cm had the highest ‘big’-IGF-II levels (for all p No significant financial relationships to disclose.

3508 Background: SPECT imaging with 111In-DTPA-trastuzumab has recently identified new tumor lesions, undetected with conventional staging, in 13/15 patients with HER2++ breast cancers (Perik et al., J Clin Oncol 2006). The aim of this study was to develop an immunoPET label, suitable for clinical use, which would allow excellent detection of HER2 positive tumor lesions and quantification of HER2 expression levels in vivo. Methods: Trastuzumab has essentially been radiolabeled as described by Verel et al. (J Nucl Med 2003). Radiochemical purity (rcp) and stability were determined by SEC-HPLC, immunoreactivity with a Lindmo assay. Biodistribution was performed in nude mice bearing HER2 positive (SKOV3) or HER2 negative (GLC4) xenografts. Five animals per group were co-injected with 111In-ITC-DTPA-trastuzumab and 89Zr-trastuzumab, imaged on a microPET (Focus 220) and sacrificed 144 hours post injection. Results: The immunoreactive fraction of 89Zr-trastuzumab was 0.96, labeling efficiency > 90% and rcp > 95%. 89Zr-trastuzumab was stable for 7 days in buffer at 4 °C and in human serum at 37 °C. MicroPET imaging showed excellent tumor uptake and could easily detect metastases with a size approximating the spatial resolution of the microPET scanner. 89Zr- and 111In-ITC-DTPA-trastuzumab showed similar biodistribution. Highest uptake was found in HER2 positive tumors at 144 hours post injection (40% ID/g tissue for 89Zr-trastuzumab and 47% ID/g for 111In-ITC-DTPA-trastuzumab) compared to 8% ID/g tissue in HER2 negative control tumors. Liver uptake was low (8–12% ID/g tissue). Preliminary results in HER2 positive breast cancer patients show excellent tumor tracer uptake and a resolution unapproachable by 111In-DTPA-trastuzumab. Conclusions: 89Zr-trastuzumab is stable, shows excellent and specific tumor uptake and is suitable for clinical use. Minimal aspecific tracer uptake in the liver allows detection of abdominal metastases. No significant financial relationships to disclose.

4085 Background: The aim of the study was to assess the value of whole body 18-fluoro-L-DOPA positron emission tomography (F-DOPA PET) for staging and restaging of patients with neuroendocrine tumo...

3063 Background: Trastuzumab combined with chemotherapy can induce remissions in HER2 positive metastatic breast cancer (MBC), but also cardiac dysfunction. The aim of this study is to evaluate whe...

Sentinel node detection in patients with breast cancer is routinely performed in our department. Images frequently show star-shaped activity at the site of injection caused by septum penetration. These star-shaped artifacts could possibly impair visualization of nearby sentinel nodes. The aim of this study was to determine whether sentinel node detection in patients with breast cancer can be improved using a medium-energy all-purpose (ME) collimator instead of a low-energy all-purpose (LEAP) collimator. For this purpose, 15 patients were studied and a phantom study was performed. The LEAP collimator was used for a dynamic study immediately after injection, and both the LEAP and the ME collimators were used for static studies. A total of 20 sentinel nodes were found with both collimators. All sentinel nodes were found in the axilla. To separate sentinel nodes from the injection site, the ME collimator gave the best results in 4 of 15 patients, but only within the first hour after injection. To separate 2 nearby sentinel nodes from each other, the LEAP collimator gave the best results in 3 of 15 patients. Our conclusion is that the LEAP collimator gave better results than the ME collimator as a result of the better resolution and the higher sensitivity. Use of the ME collimator did not improve sentinel node detection.

As the vertebral fracture status is an important and independent parameter for the prediction of future fractures, we aimed to determine the added value of spinal morphometry performed in combination with bone density measurement in the determination of vertebral fracture status in patients referred for conventional bone density measurement.Prospective, observational.Consecutive patients referred to our university medical centre department for bone mineral density measurement also underwent spinal morphometry at the same session. The primary outcome parameter was the prevalence of vertebral fractures.A total of 958 patients were included. In 28% the indication was primary osteoporosis, and in 72% it was secondary osteoporosis. In 98% spinal morphometry was technically successful. In 681 patients (71%) Lvi-Tiv and in 826 (86%) Liv-Tv were visualized. One or more fractures were found in 25% of patients; a mean of 1.8 vertebral fractures per patient. In 68% of these patients this fracture was previously unknown. Most fractures (76%) were wedge shaped. The degree of severity of the fracture was mild in 43%, moderate in 44%, and severe in 13%. Even after excluding mild fractures, the prevalence of vertebral fractures was 17%. Bone density classification was normal in 28% of patients. There was osteopenia in 43% and osteoporosis in 29%. The prevalence of vertebral fractures in these subgroups was 18%, 23% and 36% respectively.Including spinal morphometry in bone mineral density measurement is of added value as this method detected previously unknown vertebral fractures in a great number of patients.