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Background We have demonstrated recently that the tumor-to-blood standard uptake ratio (SUR) is superior to tumor standardized uptake value (SUV) as a surrogate of the metabolic uptake rate K m of fluorodeoxyglucose (FDG), overcoming several of the known shortcomings of the SUV approach: excellent linear correlation of SUR and K m from Patlak analysis was found using dynamic imaging of liver metastases. However, due to the perfectly standardized uptake period used for SUR determination and the comparatively short uptake period, these results are not automatically valid and applicable for clinical whole-body examinations in which the uptake periods (T) are distinctly longer and can vary considerably. Therefore, the aim of this work was to investigate the correlation between SUR derived from clinical static whole-body scans and K m-surrogate derived from dual time point (DTP) measurements. Methods DTP 18F-FDG PET/CT was performed in 90 consecutive patients with histologically proven non-small cell lung cancer (NSCLC). In the PET images, the primary tumor was delineated with an adaptive threshold method. For determination of the blood SUV, an aorta region of interest (ROI) was delineated manually in the attenuation CT and transferred to the PET image. Blood SUV was computed as the mean value of the aorta ROI. SUR values were computed as ratio of tumor SUV and blood SUV. SUR values from the early time point of each DTP measurement were scan time corrected to 75 min postinjection (SURtc). As surrogate of K m, we used the SUR(T) slope, K slope, derived from DTP measurements since it is proportional to the latter under the given circumstances. The correlation of SUV and SURtc with K slope was investigated. The prognostic value of SUV, SURtc, and K slope for overall survival (OS) and progression-free survival (PFS) was investigated with univariate Cox regression in a homogeneous subgroup (N=31) treated with primary chemoradiation. Results Correlation analysis revealed for both, SUV and SURtc, a clear linear correlation with K slope (P

Routine visual assessment of positron emission tomography (PET) for thoracic lymph node (LN) staging in patients with non-small cell lung cancer (NSCLC) is limited by a lack of reliable assessment criteria. This study evaluates the accuracy and inter-rater agreement of a standardized approach with unified windowing and a PET-based visual score.This retrospective analysis included pretherapeutic FDG-PET data of 86 patients with NSCLC. After standardized windowing (threshold: 2×liver SUVmean) the LN uptake was assessed visually by three independent readers with varying levels of experience using a 4-step score (1, LN uptake≤mediastinal blood pool structures (MBPS); 2, MBPSLNliver; 3, liver≤LN'black'; 4, LN appears 'black'). ROC analyses and respective areas under the curve (AUC) based on histology/cytology as standard of reference. Agreement was analyzed with Cohen's kappa (κ, pairwise) and Fleiss' κ (overall). Subgroup analyses separated between hilar vs. mediastinal LNs, adenocarcinoma vs. squamous cell carcinoma and grading G1/2 vs. G3/4.Fifty-four of the 278LNs (19.4%) were malignant (optimal cut-off to differentiate benign vs. malignant, score3). The inexperienced (n=1), advanced (n=1), and expert readers (n=1) achieved similar accuracies of 93.5%, 91.4% and 92.1%, respectively (P0.05 each). Cohen's κ ranged from 0.92 to 0.96 and Fleiss' κ was 0.93. ROC-analyses showed no significant differences between attendant readers within any subgroup (AUC, 0.92-0.96).Applying unified windowing, the introduced PET-score achieved highly accurate and robust LN assessment. This approach may shorten learning curves of inexperienced readers, facilitate multicenter trials, and improve comparability of future studies.

Background In treatment-refractory liver dominant metastatic colorectal cancer, the role of liver directed therapies still is unclear. We sought to determine a prognostic score for Y90 radioembolization in these patients. Methods We analyzed 106 patients with refractory liver dominant mCRC who had undergone a total of 178 Y90 radioembolizations with resin microspheres was collected. Potential factors influencing survival were analyzed using a Cox regression. The Log rank test served to establish prognostic factors and to form a clinical score for outcome prediction after Y90 radioembolization. Results Median survival of all patients was 6.7 months. Neither age nor prior surgical or systemic therapy nor metastatic spread had an effect on survival. In contrast, hepatic tumor load, Karnofsky index as well as CEA and CA19-9 serums level had a significant influence (p 20 %, CEA >130 ng/ml or CA19-9 > 200U/ml and Karnofsky index

Die zivilisatorische Strahlenexposition wird in den entwickelten Landern von der medizinischen Strahlenanwendung dominiert. Ein Anwendungsbereich fur den medizinischen Einsatz ionisierender Strahlung stellt dabei die Hybridbildgebung in der Kombination eines nuklearmedizinischen Schnittbildverfahrens wie der Single-Photonen-Emissions-Tomografie (SPECT) oder der Positronen-Emissions-Tomografie (PET) mit der Computertomografie (CT) dar. Durch das Hybriddesign akkumulieren die Verfahren die Expositionen aus unterschiedlichen Strahlungsarten. Die einzelnen bildgebenden Modalitaten sind Gegenstand langjahriger Optimierungen. Abweichend von der diagnostischen Anwendung kann die CT in der Hybridbildgebung, aber auch in einer low-dose-Variante zur ausschlieslichen Schwachungskorrektur und zur Lokalisationsdiagnostik durchgefuhrt werden. Durch die Nutzung moderner Spiral-CTs in den Hybridsystemen und die hier stattfindende Entwicklung iterativer Rekonstruktionsalgorithmen fur die CT-Rekonstruktion stehen neue Methoden zur Verfugung, die unter Optimierungsaspekten fur die low-dose-CT zu betrachten sind. Im Vergleich dazu etabliert sich die iterative Bildrekonstruktion in der diagnostischen Computertomografie mit Erfolg und es kann in Abhangigkeit vom Untersuchungsprotokoll eine Verminderung der CT-Exposition in der Grosenordnung um bis zu 50% bei gleichbleibender Bildqualitat realisiert werden.

Die nuklearmedizinische Diagnostik besitzt einen hohen Stellenwert fur die Primartumorsuche, das Staging und Re-Staging sowie die Therapieplanung und -kontrolle bei neuroendokrinen Neoplasien. Wie in der PET-Bildgebung neuroendokriner Neoplasien dominiert auch in der konventionellen Diagnostik die Somatostatinrezeptorszintigrafie. Analog zur PET-Bildgebung sind auch hier durch den Einsatz moderner Hybridgerate (SPECT-CT) deutliche Verbesserungen der Diagnostik zu erzielen. Daruber hinaus erlaubt der Einsatz der SPECT-CT eine Optimierung der Dosimetrie und des Therapiemonitorings von Radionuklidtherapien (Peptidradiorezeptor- oder MIBG-Therapie). Die vorliegende Arbeit spiegelt den aktuellen Stand der konventionellen nuklearmedizinischen Diagnostik wider und gibt einen Ausblick auf weitere Entwicklungen.

BACKGROUND: The intensity of chemotherapy and need for additional radiotherapy in patients with advanced stage Hodgkin's lymphoma has been unclear. We did a prospective randomised clinical trial comparing two reduced-intensity chemotherapy variants with our previous standard regimen. Chemotherapy was followed by PET-guided radiotherapy.METHODS: In this parallel group, open-label, multicentre, non-inferiority trial (HD15), 2182 patients with newly diagnosed advanced stage Hodgkin's lymphoma aged 18-60 years were randomly assigned to receive either eight cycles of BEACOPP(escalated) (8×B(esc) group), six cycles of BEACOPP(escalated) (6×B(esc) group), or eight cycles of BEACOPP(14) (8×B(14) group). Randomisation (1:1:1) was done centrally by stratified minimisation. Non-inferiority of the primary endpoint, freedom from treatment failure, was assessed using repeated CIs for the hazard ratio (HR) according to the intention-to-treat principle. Patients with a persistent mass after chemotherapy measuring 2·5 cm or larger and positive on PET scan received additional radiotherapy with 30 Gy; the negative predictive value for tumour recurrence of PET at 12 months was an independent endpoint. This trial is registered with Current Controlled Trials, number ISRCTN32443041.FINDINGS: Of the 2182 patients enrolled in the study, 2126 patients were included in the intention-to-treat analysis set, 705 in the 8×B(esc) group, 711 in the 6×B(esc) group, and 710 in the 8×B(14) group. Freedom from treatment failure was sequentially non-inferior for the 6×B(esc) and 8×B(14) groups as compared with 8×B(esc). 5-year freedom from treatment failure rates were 84·4% (97·5% CI 81·0-87·7) for the 8×B(esc) group, 89·3% (86·5-92·1) for 6×B(esc) group, and 85·4% (82·1-88·7) for the 8×B(14) group (97·5% CI for difference between 6×B(esc) and 8×B(esc) was 0·5-9·3). Overall survival in the three groups was 91·9%, 95·3%, and 94·5% respectively, and was significantly better with 6×B(esc) than with 8×B(esc) (97·5% CI 0·2-6·5). The 8×B(esc) group showed a higher mortality (7·5%) than the 6×B(esc) (4·6%) and 8×B(14) (5·2%) groups, mainly due to differences in treatment-related events (2·1%, 0·8%, and 0·8%, respectively) and secondary malignancies (1·8%, 0·7%, and 1·1%, respectively). The negative predictive value for PET at 12 months was 94·1% (95% CI 92·1-96·1); and 225 (11%) of 2126 patients received additional radiotherapy.INTERPRETATION: Treatment with six cycles of BEACOPP(escalated) followed by PET-guided radiotherapy was more effective in terms of freedom from treatment failure and less toxic than eight cycles of the same chemotherapy regimen. Thus, six cycles of BEACOPP(escalated) should be the treatment of choice for advanced stage Hodgkin's lymphoma. PET done after chemotherapy can guide the need for additional radiotherapy in this setting.FUNDING: Deutsche Krebshilfe and the Swiss Federal Government.

Background Osteopenia (OP) or osteoporosis (OST) was diagnosed by bone densitometry (DXA) in postmenopausal women free of known skeletal disorders and without acute fracture. DVO guidelines were applied to define therapeutic indication. Methods The study included 94 women aged 59-81 years. Fracture or operation ≤12 months, malignant tumor, ovariectomy, and drugs such as cortisone, strontium, fluorides, bisphosphonates, SERMs, estrogens, and steroids were exclusion criteria. The lowest T-score at the spine, femoral neck, or total hip was decisive. The indication for therapy was determined by evaluating age, BMD, and other risk factors. Results Using the WHO criteria 22.3% (n=21) had normal BMD, 52.1% (n=49) had OP, and 25.6% (n=24) had OST. According to "Dachverband Osteologie" (DVO) guidelines, 28 women (29.8%) of the whole group needed therapy. Of the 28 women receiving therapy, 9 had OP and 19 had OST. Therapy was indicated in 18.4% for OP and 79.2% for OST. Conclusion A preventive measurement of BMD with DXA provides a benefit for postmenopausal women. Combinatory assessment and consideration of other risk factors allows identification of women who might benefit from early treatment.

Objectives Cathepsin K (CatK) is expressed in high levels in osteoplasts and therefore plays an important role in bone resorption. Thus CatK serum levels may be useful in the diagnosis of chronic bone disorders such as osteopenia and osteoporosis. Therefore we aimed at studying CatK levels in women putatively free of known skeletal disorders. Study design In total, 121 voluntary women, 27 premenopausal women aged between 20 and 45 years, and 94 postmenopausal women aged 59–81 years, all free of known skeletal disorders were included. All women underwent bone density measurement, routine labor parameter and measurement of serum CatK levels. Main outcome measures Based on WHO criteria, women were stratified in four groups (premenopausal: healthy; postmenopausal: healthy, osteopenia, osteoporosis), and their CatK levels were statistically analyzed. Results Using WHO criteria 21 postmenopausal women had normal bone mineral density (BMD), 49 had osteopenia and 24 had osteoporosis. All 27 premenopausal women had normal BMD. There were no significant differences in CatK between these groups. ROC analysis resulted in poor diagnostic validity of CatK, where the area under curve was 0.544. There was no correlation neither between CatK and other biomarkers as C-telopeptide crosslaps (CTX) or bone-specific alkaline phosphatase (BAP) nor between CatK and age. Conclusions Serum levels of CatK are not suitable to differentiate women with osteoporosis from healthy subjects.

SummaryAim: This study was set up to determine the value of magnetic resonance imaging (MRI) and bone scintigraphy (BS) for the diagnosis of stress injuries in athletes, and furthermore to assess reliability and prediction of healing time. Patients, methods: Imaging data was analyzed retrospectively from 28 athletes who had received MRI and BS examinations for suspected stress injuries. MRI- and BSdata were rated by three specialists each in a blinded read, using a 5-point score (i.e. 0–4: inconspicuous to high-grade stress fracture). An interdisciplinary expert truth-panel set the reference standard. Standard statistical parameters, Fleiss' kappa (κ), and group comparisons were calculated. Results: The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for detection of stress injuries were 71.4%, 85.7%, 78.6%, 83.3% and, 75.0%, for MRI and 92.9%, 73.8%, 83.3%, 78.0% and, 91.2% for BS, respectively. Interobserver reliability for the diagnosis of a stress injury was κ = 0.9 for BS and κ = 0.85 for MRI. Mean healing times of mild (grades 1 and 2) and severe (grades 3 and 4) stress injuries were 88 days (d) versus 142d for BS and 57d versus 116d for MRI. No significant difference in healing time could be shown. Conclusions: MRI and BS reliably detect stress injuries. MRI is to be recommended as the primary imaging modality due to its potential for assessment of differential diagnoses and the lack of radiation exposure, the value of BS lies in the exclusion of stress fractures after inconclusive MRI examinations.

Zusammenfassung Die intraarterielle Selektive Interne Radiotherapie (SIRT) mit 90 Y-markierten Mikrospharen ist mittlerweile eine wichtige lokal-ablative Therapieoption fur die Behandlung onkologischer Patienten geworden. Die SIRT stellt gegenwartig einen palliativen Therapieansatz fur die Behandlung von Lebermalignomen dar. Infolge der Art des 90 Y-Zerfalls als β - -Strahler ohne eine begleitende Gammaemission, bedarf es zur Validierung der erzielten Verteilung des Radioembolisates einer Bremsstrahlungsbildgebung. Dieser Artikel demonstriert durch eine Phantommessung diese Art der Bildgebung und zeigt anhand einer Patientenstudie die Vorteile einer posttherapeutischen Schnittbildgebung. Es werden Ansatzpunkte fur weitere Optimierungen der Bremsstrahlungsbildgebung aufgezeigt.

Purpose Currently, a routine bone marrow biopsy (BMB) is performed to detect bone marrow (BM) involvement in pediatric Hodgkin's lymphoma (HL) stage greater than IIA. [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) is increasingly used for the initial staging of HL. The value of using FDG-PET to detect BM involvement has not been sufficiently defined. We compared the results of BMBs and FDG-PET for the diagnosis of BM involvement in a large pediatric group with HL. Patients and Methods The initial staging of 175 pediatric patients with newly diagnosed classical HL stage greater than IIA was determined by using BMB, FDG-PET, chest computed tomography (CT), and magnetic resonance imaging (MRI) or CT of the neck, abdomen, and pelvis. Staging images were prospectively evaluated by a central review board. Skeletal regions that were suggestive of BM involvement by either method were re-evaluated by using different imaging modalities. In suspicious cases, bone scintigraphy was performed. If follow-up FDG-PET scans were available, the remission of skeletal lesions during treatment was evaluated. Results BMB results were positive in seven of 175 patients and were identified by FDG-PET. FDG-PET scans showed BM involvement in 45 patients. In addition, the lesions of 32 of these 45 patients had a typical multifocal pattern. In 38 of 39 follow-up positron emission tomography scans, most of the skeletal lesions disappeared after chemotherapy. There was no patient with skeletal findings suggestive of BM involvement by MRI or CT with a negative FDG-PET. Conclusion FDG-PET is a sensitive and specific method for the detection of BM involvement in pediatric HL. The sensitivity of a BMB appears compromised by the focal pattern of BM involvement. Thus, FDG-PET may safely be substituted for a BMB in routine staging procedures.

Clinically, Alzheimer’s disease (AD) is by far the most common cause of dementia. Criteria for the diagnosis of dementia with Lewy bodies (DLB) are highly specific but not at all sensitive, which is reflected by the higher number of DLB cases detected histopathologically at autopsy. Imaging of dopamine transporter with FP-CIT SPECT is one possibility to increase sensitivity. Pathological confirmation was also included in the revised consensus criteria for the diagnosis of DLB. However, in the absence of parkinsonism, one of the core features, a clinical diagnosis of AD is more likely. The role of FP-CIT SPECT in DLB diagnosis remains to be clarified. Based on our 3 case reports and a review of the literature, the utility of this imaging method in the differential diagnosis of AD and DLB is highlighted.

To evaluate the efficacy of a workflow consisting of repeat assessment in patients planned for yttrium-90 ((90)Y) radioembolization in case of nontarget visceral technetium-99m ((99m)Tc)-macroaggregated albumin (MAA) accumulation despite initial prophylactic coil embolization of nonhepatic arteries.In 341 patients with primary and secondary liver cancer, pretreatment hepatic angiograms, as well as single-photon emission computed tomography coregistered with magnetic resonance imaging scans, were obtained. Extrahepatic tracer deposition was identified in 33 patients (9.7%) necessitating repeat assessment. Images were reviewed to correlate the site of MAA accumulation with causative gastrointestinal vessels, and repeat angiograms served as reference standard.At repeat angiography, the source of extrahepatic flow was identified and eliminated in 31 of 33 patients (93.9%). In 20 patients (60.6%), successful embolization of nontarget vessels was achieved, in 13 patients (39.4%), MAA was administered more distally. Afterward, extrahepatic MAA deposition was eliminated in 30 patients (90.9%).The algorithm of repeat assessment in case of extrahepatic MAA accumulation has proven highly effective to eliminate extrahepatic shunting, thus decreasing the risk of postradioembolization complications due to inadvertent visceral microsphere deposition.

This study was designed to evaluate overall survival after radioembolization or best supportive care (BSC) in patients with chemotherapy-refractory liver-dominant metastatic colorectal cancer (mCRC). This was a matched-pair comparison of patients who received radioembolization plus BSC or BSC alone for extensive liver disease. Twenty-nine patients who received radioembolization were retrospectively matched with a contemporary cohort of >500 patients who received BSC from 3 centers in Germany. Using clinical databases, patients were initially matched for prior treatments and tumor burden and then 29 patients were consecutively identified with two or more of four matching criteria: synchronous/metachronous metastases, tumor burden, increased ALP, and/or CEA >200 U/ml. Survival was calculated from date of progression before radioembolization or BSC by using Kaplan–Meier analysis. Of 29 patients in each study arm, 16 pairs (55.2%) matched for all four criteria, and 11 pairs (37.9%) matched three criteria. Patients in both groups had a similar performance status (Karnofsky index, median 80% [range, 60–100%]). Compared with BSC alone, radioembolization prolonged survival (median, 8.3 vs. 3.5 months; P

REPLY: Thank you for giving us the opportunity to respond to the letter to the editor. Chiesa and coauthors raise sincere concerns over the study’s methodology and deny the negative outcome reported for the use of pretherapeutic 99mTc-macroaggregated albumin (99mTc-MAA) uptake for prediction of

Background Dopaminergic availability is known to linearly decline in Parkinson's disease (PD). In contrast, temporal characteristics of serotonergic markers like the serotonin transporter (SERT) in relation to clinical staging of PD and dopaminergic cell loss are less clear. This study investigated SERT availability using [(123) I]-ADAM and single-photon emission tomography (SPECT) in drug-naive, de novo patients, i.e., in a PD stage where dopaminergic decline starts to lead to the occurrence of the characteristic motor symptoms. Methods Nine de novo patients with PD and 9 age-matched healthy controls were studied. Measurements were repeated after 3 months of levodopa treatment in patients with PD, and dopaminergic transporter (DAT) binding was examined at baseline using [(123) I]-FP-CIT SPECT. Results No alterations of SERT availability were found between groups, and neither correlation between SERT and DAT nor effects of levodopa treatment on SERT was found in patients with PD. Conclusions These preliminary findings indicate that midbrain SERT is preserved in unmedicated patients at this early stage of PD, supporting the view that serotonergic decline temporally follows dopaminergic cell loss.

Purpose To determine the additional value of fluorodeoxyglucose-positron emission tomography (PET) for clinical target volume definition in the planning of computed tomography (CT)-guided interstitial brachytherapy for liver metastases. Patients and Methods A total of 19 patients with liver metastases from colorectal cancer treated in 25 sessions were included in the present study. All patients had undergone fluorodeoxyglucose-PET for patient evaluation before interstitial CT-guided brachytherapy. A contrast-enhanced CT scan of the upper abdomen was obtained for radiation planning. The clinical target volume (CTV) was defined by a radiation oncologist and radiologist. After registration of the CT scan with the PET data set, the target volume was defined again using the fusion images. Results PET revealed one additional liver lesion that was not visible on CT. The median CT-CTV (defined using CT and magnetic resonance imaging) was 68 cm 3 (range 4–260). The PET/CT-CTV (median, 78 cm 3 ; range, 4–273) was significantly larger, with a median gain of 24.5% (interquartile range, 2.1–71.5%; p = .022). An increased CTV was observed in 15 cases and a decrease in 6; in 4 cases, the CT-CTV and PET/CT-CTV were equal. Incomplete dose coverage of PET/CT-CTVs was indicative of early local progression ( p = .004); however, CT-based radiation plans did not show significant differences in the local control rates when stratified by dose coverage. Conclusion Retrospective implementation of fluorodeoxyglucose-PET for CTV specification for CT-guided brachytherapy for colorectal liver metastases revealed a significant change in the CTVs. Additional PET-positive tumor regions with incomplete dose coverage could explain unexpected early local progression.

Das Ziel dieser Leitlinie ist es, dem nuklearmedizinischen und ggf. interdisziplinaren Team Hilfestellungen fur die Indikationsstellung, Durchfuhrung, Interpretation und Dokumentation der Positronenemissionstomographie (PET) und der Kombination mit der Computertomographie (PET/CT) bei Kindern mit malignen Erkrankungen zu geben. Im Wesentlichen wird auf die Anwendung von 18F-Fluordesoxyglukose eingegangen. Diesen Empfehlungen liegt die aktuelle Leitlinie des Paediatric Committee der EANM zugrunde, die ins Deutsche ubertragen und an die aktuellen Gegebenheiten in Deutschland angepasst wurde. Das Thema Anpassung der CT-Parameter bei der PET/CT im Kindesalter wird ausfuhrlicher behandelt als in der EANM-Leitlinie. Dies berucksichtigt, dass in Deutschland ein Grosteil der PET-Untersuchungen an PET/CT-Geraten durchgefuhrt wird, und ein unkritisches Ubernehmen der Erwachsenenprotokolle fur die CT-Komponente zu einer nicht zu tolerierenden Strahlenexposition der Kinder fuhrt. Diese Empfehlungen verstehen sich als Erganzung der Leitlinien fur die FDG-PET und PET/CT in der Onkologie, wie sie von der Deutschen Gesellschaft fur Nuklearmedizin (DGN) und der European Association of Nuclear Medicine (EANM) publiziert wurden. Die Erganzungen betreffen ausschlieslich die speziellen Anforderungen bei der Untersuchung von Kindern. Diese Empfehlungen mussen immer im Zusammenhang mit lokalen und aktuellen nationalen Qualitatsstandards und Vorschriften gesehen werden.

Aim: Retrospective evaluation of the impact of integrated positron emission tomography/computed tomography (PET/CT) using 68Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide (68Ga-DOTATOC) on the therapeutic management of patients with neuroendocrine tumors (NET). Methods: The 68Ga-DOTATOC-PET/CT data of 66 patients (31 male, 35 female; age: 29–79, mean age: 56 years) with known or suspected NET were included. Imaging data (PET and triple-phase contrast-enhanced CT) were evaluated in consensus by two readers for the visualization of NET manifestations. Combined PET/CT, clinical and imaging follow-up as well as histopathology (if available) served as the reference standard. In order to assess the impact of the respective submodalities on the therapeutic strategy chosen, the results were compared to the treatment decision made by the interdisciplinary NET tumor board of our institution. Results: Two of the initial 66 patients included did not suffer from NET according to further immunohistopathological examination. In 50 of the remaining 64 (78%) NET patients, a total of 181 NET manifestations were detected by PET/CT. 59/181 (32.6%) were detected by one submodality only (CT 17.1%, PET 15.5%, p for comparison of both = 0.459). Combined PET/CT reading had an impact on the therapeutic management in 24 of 64 (38%) NET patients: primary resection (n = 5), curative lymph node resection (n = 1), initiation/switch of chemotherapy (CTx) due to progressive disease (n = 10), no surgery due to systemic disease (n = 2), radiopeptide receptor therapy instead of CTx (n = 1), additional bisphosphonate therapy (n = 4), and hepatic brachytherapy (n = 1). In 12 of 24 (50%) of these patients, relevant findings were detected by a single submodality only: CT (n = 5), PET (n = 7); p for comparison = 0.774). Conclusion:68Ga-DOTATOC-PET/CT influences therapeutic management in about one third of patients examined. CT and PET are comparably sensitive, deliver complementary information and equally contribute to therapeutic decision-making. Thus, despite the merits of the PET modality, the CT component must not be neglected and an optimized multiphase CT protocol is recommended.

Purpose In adult Hodgkin's lymphoma (HL) risk stratification after early therapy response assessment with [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) seems to allow tailoring therapy with less toxicity for patients with adequate metabolic response. This study delivers the first prospective data on the potential of FDG-PET for response assessment in pediatric HL. Patients and Methods FDG-PET was performed in 40 pediatric HL patients before polychemotherapy (PET-1), after two cycles of polychemotherapy (PET-2), and after completion of polychemotherapy (PET-3). Mean follow-up was 46 months (range, 26 to 72 months). Results At early and late response assessment, the proportion of PET-negative patients was significantly higher compared with those patients with negative findings in conventional imaging methods (CIMs; PET-2, 26 of 40 v CIM-2, one of 40; P < .001; PET-3, 21 of 29 v CIM-3, four of 29; P < .001). Sensitivity and negative predictive value were 100% for early and late therapy response assessment by PET. Both patients suffering a relapse during follow-up were identified by PET-2/3, whereas one of these patients was not detected by CIM-3. PET was superior to CIMs with regard to specificity in early and late therapy response assessment (68% v 3%, and 78% v 11%, respectively; both P < .001). Specificity of early therapy response assessment by PET was improved to 97% by quantitative analysis of maximal standardized uptake value reduction using a cutoff value of 58%. Conclusion Pediatric HL patients with a negative PET in response assessment have an excellent prognosis while PET-positive patients have an increased risk for relapse.

Objectives Different techniques for measuring of perfusion are clinically available, but these are usually applied to healthy brain tissue. Material and methods Five different techniques were used here in 12 patients with brain tumors to investigate the impact of tumor vascularization on the perfusion signal: three qualitative dynamic contrast-enhanced/susceptibility-contrast magnetic resonance imaging (DCE-MRI/DSC-MRI) techniques exploiting T1, T2, T 2 * contrast, and two quantitative techniques, pulsed arterial spin labeling (PASL) and H215O positron emission tomography (H215O-PET). Results In a first approximation, a linear correlation was found between all five imaging modalities regarding the perfusion signal of both, normal brain tissue and tumor. The estimated values for tumor perfusion differed significantly between the techniques (1 = methodical mean in arbitrary units): PASL: 0.83, H215O-PET: 0.62, T1-DCE: 1.73, T2-DCE: 0.69, T 2 * -DSC : 0.89. Conclusions The tumor perfusion values, determined with different techniques are not comparable. The T 2 * -DSC , here applied with contrast agent presaturation of extravascular space, and PASL depict median perfusion most reliably.

To evaluate FDG-PET for staging, grading, preoperative response assessment and posttherapeutic evaluation in children with Wilms tumour (WT). In this study, 23 FDG-PET examinations in 12 paediatric patients (female, n = 5; male, n = 7; age, 1–19 years) with WT (primary, n = 9; relapsed, n = 3) were analysed. All patients were examined with conventional imaging methods (CIM) according to the SIOP2001/GPOH trial protocol. Additionally, FDG-PET/PET-CT was performed for staging (n = 12), preoperative response assessment (n = 6) and posttherapeutic evaluation (n = 5). Imaging results of FDG-PET and CIM were analysed regarding the accuracy in tumour visualisation, impact on therapeutic management and preoperative response assessment, with clinical follow-up and histopathology as the standard of reference. FDG-PET and CIM showed concordant results for staging of primary WT, whereas FDG-PET was superior in 1/3 cases with recurrent WT. Concerning histological differentiation, one case with anaplastic WT had an standard uptake value (SUV) of 12.3, which was remarkably higher than the average SUV in the eight cases with intermediate risk histology. No parameter analysed for PET or CIM was reliably predictive for histological regression or clinical outcome. After completion of therapy, FDG-PET was superior to CIM in 2/5 cases in detecting residual disease with therapeutic relevance. FDG-PET does not provide additional information to the traditional imaging work-up for staging WT patients, preoperative response assessment and clinical outcome. FDG-PET was advantageous in ruling out residual disease after completion of first line treatment and in pretherapeutic staging of relapse patients. Furthermore, there seems to be a good correlation of initial SUV and histological differentiation.

The purpose of the study was to establish a diagnostic approach to the preparation of patients with colorectal liver metastases considered for transarterial radioembolization (RE). Twenty-two patients sequentially underwent computed tomography (CT; thorax/abdomen), magnetic resonance imaging (MRI; liver; hepatocyte-specific contrast), positron emission tomography (PET/PET-CT; F18-fluoro-desoxy-glucose), and angiography with perfusion scintigraphy [planar imaging; tomography with integrated CT (SPECT-CT)]. The algorithm was continued when no contraindication or alternative treatment option was found. The impact of each test on the therapy decision and RE management was recorded. Patient evaluation using CT revealed contraindications for RE in 4/22 patients (18%). Of the remaining 18 patients, 2 were excluded and 3 were assigned to locally ablative treatment based on MRI and PET results (28%). The remaining 13 patients entered the planning algorithm: SPECT-CT revealed gastrointestinal tracer accumulations in 4 (31%) patients [SPECT, 2 (15%)], making a modified application necessary. In five patients (38%), planar scintigraphy revealed relevant hepatopulmonary shunting. Therapy was finally administered to all 13 patients without therapy-related pulmonary or gastrointestinal morbidity. Each part of the diagnostic algorithm showed a relevant impact on patient management. The sequential approach appears to be suitable and keeps the number of unnecessary treatments and therapy risks to a minimum.

Purpose The objective of this study was to evaluate the impact of positron emission tomography (PET) using fluorine-18–fluorodeoxyglucose (FDG) for initial staging and therapy planning in pediatric sarcoma patients. Patients and Methods In this prospective multicenter study, 46 pediatric patients (females, n = 22; males, n = 24; age range, 1 to 18 years) with histologically proven sarcoma (Ewing sarcoma family tumors, n = 23; osteosarcoma, n = 11; rhabdomyosarcoma, n = 12) were examined with conventional imaging modalities (CIMs), including ultrasound, computed tomography (CT), magnetic resonance imaging, and bone scintigraphy according to the standardized algorithms of the international therapy optimization trials, and whole-body FDG-PET. A lesion- and patient-based analysis of PET alone and CIMs alone and a side-by-side (SBS) analysis of FDG-PET and CIMs were performed. The standard of reference consisted of all imaging material, follow-up data (mean follow-up time, 24 ± 12 months), and histopathology and was determined by an interdisciplinary tumor board. Results FDG-PET and CIMs were equally effective in the detection of primary tumors (accuracy, 100%). PET was superior to CIMs concerning the correct detection of lymph node involvement (sensitivity, 95% v 25%, respectively) and bone manifestations (sensitivity, 90% v 57%, respectively), whereas CT was more reliable than FDG-PET in depicting lung metastases (sensitivity, 100% v 25%, respectively). The patient-based analysis revealed the best results for SBS, with 91% correct therapy decisions. This was significantly superior to CIMs (59%; P < .001). Conclusion In staging pediatric sarcoma, subsidiary FDG-PET scanning depicts important additional information and has a relevant impact on therapy planning when analyzed side-by-side with CIMs.

Somatostatin receptor (SSTR) scintigraphy is currently used as one standard imaging modality in neuroendocrine tumors (NETs). However, future optimization of NET imaging may be achieved with positron emission tomography based methods utilizing more sensitive and specific tracers in combination with computed tomography or magnetic resonance imaging. Here we established an orthotopic mouse model that reflects relevant aspects of human pancreatic NETs such as SSTR expression, dense vascularization and metastatic disease. This model was then utilized to test the feasibility of combined magnetic resonance imaging and animal positron emission tomography. Orthotopic implantation of amphicrine, SSTR-positive pancreatic AR42J cells resulted in rapidly growing tumors, with concomitant metastatic spread into abdominal lymph nodes and peritoneal cavity. Primary tumors as well as their metastases expressed the neuroendocrine markers chromogranin A and synaptophysin. For imaging experiments, the SSTR ligands 68Ga-DOTATOC or 68Ga-DOTANOC were injected intravenously, and animals were subsequently examined in an animal positron emission tomography scanner and a clinical 3T (tesla) magnetic resonance imager. All animals showed radionuclide accumulation in the primary tumor. Definite anatomical correlation was achieved using digital image fusion of the positron emission tomography and magnetic resonance imaging data. 68Ga-DOTANOC strongly accumulated in the tumor tissue (mean 6.6-fold vs. control tissues) when compared to 68Ga-DOTATOC, which showed a higher renal clearance. In good agreement with the biodistribution data, the kidney-to-tumor ratio was higher for 68Ga-DOTATOC (2.43-fold vs. 1.75-fold). Consequently, 68Ga-DOTANOC achieved better signal enhancement in the primary tumor and allowed for detection of metastatic lesions. In summary, we established a novel orthotopic pancreatic SSTR-positive tumor model and used this model to provide proof of principle for the diagnostic combination of SSTR-based molecular imaging and magnetic resonance imaging. Specifically, the animal model allowed the comparative evaluation of 68Ga-DOTANOC and 68Ga-DOTATOC, with 68Ga-DOTANOC providing better tumor-specific accumulation and renal activity. We conclude that this animal model will be of innovative value for further investigation in the imaging of NETs.

AIM Somatostatin receptor scintigraphy (SRS) is well-established in neuroendocrine tumour (NET) imaging. This study evaluated the impact of attenuation correction (AC) on SRS SPECT data in patients examined by SPECT-CT. METHODS Planar scintigraphy and SPECT-CT of 17 patients (10 men, seven women; age, 40-74 years; mean, 62 years) suffering from NET were included. For the visual assessment of AC, the intensity and contrast of foci classified as pathological were rated in both the non-attenuation corrected (NAC) and the attenuation corrected (AC) SPECT images using a 5-point score. The change in signal intensity after AC was semiquantified two-fold for each focus in both SPECT(AC) and SPECT(NAC): firstly by using tumour-to-background (TB) ratios (defined as T(max)/B(mean)) for the determination of a TB(AC)/TB(NAC) ratio. Secondly, by a T(max,AC)/T(max,NAC) ratio. Both ratios were correlated to the focus depth. RESULTS A total of 46 pathological foci were found. Focus contrast and intensity significantly increased in 14/46 foci (30%) after AC (mean, 3.7-4.0) in the visual analysis (P

Aim. To assess the outcomes of patients with unresectable intrahepatic cholangiocellular carcinoma (ICC) treated by a tailored therapeutic approach, combining systemic with advanced image-guided local or locoregional therapies.Materials and Methods. Treatment followed an algorithm established by a multidisciplinary GI-tumor team. Treatment options comprised ablation (RFA, CT-guided brachytherapy) or locoregional techniques (TACE, radioembolization, i.a. chemotherapy).Results. Median survival was 33.1 months from time of diagnosis and 16.0 months from first therapy. UICC stage analysis showed a median survival of 15.9 months for stage I, 9 months for IIIa, 18.4 months for IIIc, and 13 months for IV. Only the number of lesions, baseline serum CEA and serum CA19-9, and objective response (RECIST) were independently associated with survival. Extrahepatic metastases had no influence.Conclusion. Patients with unresectable ICC may benefit from hepatic tumor control provided by local or locoregional therapies. Future prospective study formats should focus on supplementing systemic therapy by classes of interventions (“toolbox”) rather than specific techniques, that is, local ablation leading to complete tumor destruction (such as RFA) or locoregional treatment leading to partial remission (such as radioembolization). This trial is registered with German Clinical Trials Registry (Deutsche Register Klinischer Studien), DRKS-ID:DRKS00006237.

Previous studies with positron emission tomography (PET) and the glucose analog F-18-fluorodeoxyglucose (FDG) in patients with neurofibromatosis type 1 (NF1) suggest reduced cerebral glucose metabolism in NF1 specifically in the thalamus. The latter is distinguished by extensive neural circuitry connections which makes thalamic hypoactivity in NF1 an interesting finding. Yet it is not very well confirmed, since previous studies were limited by small sample size and/or poorly matched control groups. Primary aim of the present study therefore was to compare brain FDG PET between a large sample of NF1 patients and a well-matched control group. Secondary aim was to test for an NF1-associated FDG effect in the amygdala, as increased blood flow in the amygdala has recently been detected in a mouse model of NF1. Fifty adult NF1 patients and 50 gender- and age-matched control subjects were included retrospectively. Voxel-wise comparison of brain FDG uptake was performed using the statistical parametric mapping (SPM8). Additional region-of-interest (ROI) analysis was performed using standard ROI templates. Voxel-based testing revealed a single 11.2 ml cluster of reduced FDG uptake in the thalamus of NF1 patients. There was no further significant cluster throughout the whole brain including the amygdala, neither hypo nor hyper. ROI-analysis confirmed reduction of thalamic FDG uptake in the NF1 group (p

Purpose: To investigate and compare the quantitative accuracy of 90Y imaging across different generation PET/CT scanners, for the purpose of dosimetry after radioembolization with resin microspheres. Methods: A strict experimental and imaging protocol was followed by 47 international sites using the NEMA 2007/IEC 2008 PET body phantom with an 8-to-1 sphere-to-background ratio of 90Y solution. The phantom was imaged over a 7-day period (activity ranging from 0.5 to 3.0 GBq) and all reconstructed data were analysed at a core laboratory for consistent processing. Quantitative accuracy was assessed through measures of total phantom activity, activity concentration in background and hot spheres, misplaced counts in a nonradioactive insert, and background variability. Results: Of the 69 scanners assessed, 37 had both time-of-flight (ToF) and resolution recovery (RR) capability. These current generation scanners from GE, Philips and Siemens could reconstruct background concentration measures to within 10 % of true values over the evaluated range, with greater deviations on the Philips systems at low count rates, and demonstrated typical partial volume effects on hot sphere recovery, which dominated spheres of diameter 20 mm in diameter, activity concentrations were consistently underestimated by about 20 %. Non-ToF scanners from GE Healthcare and Siemens were capable of producing accurate measures, but with inferior quantitative recovery compared with ToF systems. Conclusion: Current generation ToF scanners can consistently reconstruct 90Y activity concentrations, but they underestimate activity concentrations in small structures (≤37 mm diameter) within a warm background due to partial volume effects and constraints of the reconstruction algorithm. At the highest count rates investigated, measures of background concentration (about 300 kBq/ml) could be estimated on average to within 1 %, 5 % and 2 % for GE Healthcare (all-pass filter, RR + ToF), Philips (4i8s ToF) and Siemens (2i21s all-pass filter, RR + ToF) ToF systems, respectively. Over the range of activities investigated, comparable performance between GE Healthcare and Siemens ToF systems suggests suitability for quantitative analysis in a scenario analogous to that of postradioembolization imaging for treatment of liver cancer., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Methods: Fifteen patients (f, 6; m, 9; median age, 59 years; range, 32 to 72 years) with 28 liver metastases were included retrospectively. FDG-PET/CT imaging (median activity, 237 MBq; range, 231 to 252 MBq; median uptake, 61 min; range, 55 to 67 min) was performed on a Siemens Biograph mCT 64 followed by image reconstruction using 3D-ordered subset expectation maximization (3D-OSEM) or 3D-OSEM with PSF modeling - both with and without TOF information. Differences in SUVmax were analyzed using the Friedman test and Wilcoxon test for paired non-parametric data. The correlation of inter-method differences with the lesions’ TBR was studied using Spearman’s rank correlation coefficient (rho). Differences between lesions with low (4.8) TBR were analyzed using the Mann-Whitney U test (TBR measured with 3D-OSEM; binarized by its median). Background: The maximum standardized uptake value (SUVmax) is a common clinical parameter for quantification in F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), but it is influenced by image reconstruction. The aim of this study was to analyze the association of SUVmax deviations related to point spread function (PSF) and time-of-flight (TOF) reconstruction with tumor-to-background ratios (TBR) in colorectal liver metastases (CRLM). Results: There was a significant correlation of the lesions’ TBR with relative SUVmax differences related to PSF (PSF + TOF vs. 3D-OSEM + TOF, rho = 0.61; PSF vs. 3D-OSEM, rho = 0.52) or TOF (PSF + TOF vs. PSF, rho = −0.58; 3D-OSEM + TOF vs. 3D-OSEM, rho = −0.61). Accordingly, PSF algorithms only showed higher SUVmax than non-PSF algorithms in lesions with a high TBR (median differences at low/high TBR, +2.6%/+9.1% [PSF + TOF vs. 3D-OSEM + TOF]; +0.7%/+6.4% [PSF vs. 3D-OSEM]). TOF integration also led to higher SUVmax but mainly at low TBR (low/high TBR, +10.4%/+1.8% [PSF + TOF vs. PSF]; +8.6%/−0.1% [3D-OSEM + TOF vs. 3D-OSEM]). Conclusions: Both PSF and TOF reconstruction resulted in a substantial alteration of SUVmax in CRLM. TOF provided the highest SUVmax increase in low-contrast lesions while - vice versa - PSF showed the most relevant increase in high-contrast lesions. Thus, one should be aware that quantitative analyses of lesions with varying TBR, e.g., in radiotherapy or follow-up studies, may be mainly affected by either PSF or TOF reconstruction, respectively.

Background The diagnosis of hip pain after total hip replacement (THR) represents a highly challenging question that is of increasing concern to orthopedic surgeons. This retrospective study assesses bone scintigraphy with Hybrid SPECT/CT for the diagnosis of painful THR in a selected cohort of patients. Methods Bone SPECT/CT datasets of 23 patients (mean age 68.9 years) with a painful hip after THR were evaluated. Selection of the patients required an inconclusive radiograph, normal serum levels of inflammatory parameters (CRP and ESR) or a negative aspiration of the hip joint prior to the examination. The standard of reference was established by an interdisciplinary adjudication-panel using all imaging data and clinical follow-up data (>12 month). Pathological and physiological uptake patterns were defined and applied. Results The cause of pain in this study group could be determined in 18 out of 23 cases. Reasons were aseptic loosening (n = 5), spine-related (n = 5), heterotopic ossification (n = 5), neuronal (n = 1), septic loosening (n = 1) and periprosthetic stress fracture (n = 1). In (n = 5) cases the cause of hip pain could not be identified. SPECT/CT imaging correctly identified the cause of pain in (n = 13) cases, in which the integrated CT-information led to the correct diagnosis in (n = 4) cases, mainly through superior anatomic correlation. Loosening was correctly assessed in all cases with a definite diagnosis. Conclusions SPECT/CT of THA reliably detects or rules out loosening and provides valuable information about heterotopic ossifications. Furthermore differential diagnoses may be detected with a whole-body scan and mechanical or osseous failure is covered by CT- imaging. SPECT/CT holds great potential for imaging-based assessment of painful prostheses.

The value of different correlative imaging strategies with F18-fluorodeoxyglucose positron emission tomography (FDG-PET) and conventional imaging modalities (CIM) for initial staging of pediatric Hodgkin disease (HD) was assessed.Thirty-three patients (age, 4 to 18 y) with histologically proven HD underwent initial staging with computed tomography (thorax), magnetic resonance imaging (neck, abdomen, pelvis), and FDG-PET in a prospective study. Image fusion (PET-CIM) was performed using a semiautomatic voxel-based algorithm. Analysis of separate, side-by-side (SBS) and fused PET and CIM was performed evaluating 21 nodal and 6 extranodal regions per patient for presence of lymphoma, applying a 5-point confidence scale. The reference data was clinical follow-up (12 mo).Concerning lymph node regions above and below the diaphragm the accuracy of CIM, PET, SBS, and image fusion was 86%, 89%, 94%, 97%, and 94%, 94%, 97%, 98%. In extranodal regions, the accuracy was 96%, 96%, 100%, and 100%. The reviewers' confidence was improved significantly by image fusion. Staging and therapy assignment on the basis of CIM was correctly modified by SBS in 5 and 4, by image fusion in 7 and 5 patients.Combined reading of FDG-PET and CIM is crucial for accurate staging in pediatric HD. Image fusion improves the observers' confidence and has impact on the therapeutic management.

Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. 123I-FP-CIT/123I-β-CIT SPECT and 123I-IBZM SPECT as well as 18F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. 18F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD. © 2006 Movement Disorder Society

We studied the midbrain SERT availability in patients with major depression and assessed the relation of SERT occupancy by citalopram to the treatment response. 21 non-medicated patients with major depression and 13 healthy controls were examined by [(123)I]-ADAM SPECT. The midbrain SERT availability (SERT V(3)'') was calculated using individual MRI scans. In 13/21 patients SPECT was repeated 7 days after oral medication with citalopram (10 mg/day). We found no significant difference in the mean midbrain SERT availability between the studied patients with major depression and healthy controls (0.86 +/- 0.27 vs. 0.71 +/- 0.44, p = 0.069). The mean SERT occupancy accounted to 61%. The degree of SERT blockade by citalopram did not correlate with the reduction in HAMD total score. Treatment with low-dosed citalopram caused individually variable occupancy of the midbrain-SERT and a rapid clinical improvement in 54% of the investigated patients.

Thermotherapy using magnetic nanoparticles (nano cancer therapy) is a new concept of local tumour therapy, which is based on controlled heating of intra-tumoural injected magnetic nanoparticles. The aim of this study was to evaluate the usefulness of PET with a recently introduced amino acid tracer O-(2-[18F]fluoroethyl)-]L-tyrosine (FET) for targeting the nanoparticles implantation.Eleven patients with glioblastoma recurrences underwent MR and FET-PET imaging for planning of the nano cancer therapy. Thereafter, the gross tumour volumes (GTV) were defined, taking into consideration the results of both imaging tools.The MRI-based mean GTV was 24.3 cm3 (range 2.5-59.7) and the PET-based mean GTV 31.9 cm3 (range 5.2-77.9). On the average the MRI identified an additional 8.9 +/- 4.7 cm3 and the FET-PET scan-an additional 16.5 +/- 15.2 cm3 outside of the common GTV (15.4 +/- 11.0 cm3). The mean final GTV accounted to 33.8 cm3 (range, 5.2-77.9). The additional information of FET-PET led to an increase in GTV by 22-286% in eight patients and to a decrease of 23% and 26%, respectively, in two patients. In one patient, the final GTV was defined on the basis of MRI data only.FET-PET adds important information on the actual tumour volume in recurrent glioblastomas and is highly valuable for defining the target volume for the nano cancer therapy.

In patients with Ewing sarcoma, precise staging is not only crucial for the therapeutic regimen but also for a reliable evaluation of response to therapy. We report on a 15-year-old girl with metastatic spread of a Ewing sarcoma who, apart from conventional staging by bone scan, chest X-ray and CT, was subsidiary examined by FDG-PET and whole-body MRI before and after chemotherapy. Both modalities detected more bone lesions than the bone scan, which led to an altered strategy for radiotherapy. Both examinations might be a great asset to stage-adjusted therapy regimens, ultimately influencing patient outcome.

Summary Aim: Comparison of two gated SPECT analysis tools – gated SPECT quantification (GSQ) and emory cardiac toolbox (ECT) – in patients with coronary artery disease (CAD) and severely impaired left ventricular function (preoperative: EF

Background: Nuclear medicine imaging is increasingly used in the evaluation of tumors of the head and neck. In the current study, we assess the value of single-photon emission tomography (SPECT) us

This study assessed the value of image fusion with (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients suspected of having pancreatic cancer.32 patients (12 women, 20 men; age 24-79 years; mean 56.6 years) were included. All patients underwent whole-body FDG-PET examinations and contrast-enhanced MRI. Image fusion used a semiautomatic voxel-based algorithm. Separate reading, side-by-side analysis and evaluation of fused PET/MRI images were performed. Results were correlated to histopathology (n = 30), or clinical follow-up (n = 2).15/32 patients had pancreas cancer and 17/32 patients benign disease. The sensitivity and specificity for cancer detection by FDG-PET were 93 and 41% for visual and 86 and 58% for semiquantitative analysis whereas MRI achieved 100 and 76% respectively. Topographical assignment of PET foci by image fusion was superior to side-by-side analysis in 11/39 (28%) foci (in 8/32 patients). However, a true impact on therapeutic strategy was observed only in 1/8 patients as the presence of multiple metastases, irresectable primaries or medical reasons for inoperability prevented a curative setting.Compared to side-by-side analysis, PET/MRI image fusion improves the anatomical assignment and interpretation of FDG foci. The therapeutic benefit for the patient however is limited in patients with multiple lesions or incurable primaries.

The aim of this study was to compare CT, MRI and FDG-PET in the prediction of outcome of neoadjuvant radiochemotherapy in patients with locally advanced primary rectal cancer. A total of 23 patients with T3/4 rectal cancer underwent a preoperative radiochemotherapy combined with regional hyperthermia. Staging was performed using four-slice CT (n=23), 1.5-T MRI (n=10), and (18)F-FDG-PET (n=23) before and 2-4 weeks after completion of neoadjuvant treatment. Response criteria were a change in T category and tumour volume for CT and MRI and a change in glucose uptake (standard uptake value) within the tumour for FDG-PET. Imaging results were compared with those of pretherapy endorectal ultrasound and histopathological findings. Histopathology showed a response to neoadjuvant therapy in 13 patients whereas 10 patients were classified as nonresponders. The mean SUV reduction in responders (60+/-14%) was significantly higher than in nonresponders (37+/-31%; P=0.030). The sensitivity and specificity of FDG-PET in identifying response was 100% (CT 54%, MRI 71%) and 60% (CT 80%, MRT 67%). Positive and negative predictive values were 77% (CT 78%, MRI 83%) and 100% (CT 57%, MRI 50%) (PET P=0.002, CT P=0.197, MRI P=0.500). These results suggest that FDG-PET is superior to CT and MRI in predicting response to preoperative multimodal treatment of locally advanced primary rectal cancer.

This study compared different magnetic resonance imaging (MRI) methods with Tl(201) single photon emission computerized tomography (SPECT) and the "gold standard" for viability assessment, functional recovery after coronary artery bypass grafting (CABG). Twenty patients (64+/-7.3 years) with severely impaired left ventricular function (ejection fraction [EF] 28.6+/-8.7%) underwent MRI and SPECT before and 6 months after CABG. Wall-motion abnormalities were assessed by stress cine MRI using low-dose dobutamine. A segment with a nonreversible defect in Tl(201)-SPECT and a delayed enhancement (DE) in an area50% of the entire segment, as well as an end-diastolic wall thickness6 mm, was defined as nonviable. The mean postoperative EF (n=20) improved slightly from 28.6+/-8.7% to 32.2+/-12.4% (not significant). Using the Tl(201)-SPECT as the reference method, end-diastolic wall thickness, MRI-DE, and stress MRI showed high sensitivity of 94%, 93%, and 84%, respectively, but low specificities. Using the recovery of contractile function 6 months after CABG as the gold standard, MRI-DE showed an even higher sensitivity of 99%, end-diastolic wall thickness 96%, stress MRI 88%, and Tl(201)-SPECT 86%. MRI-DE showed advantages compared with the widely used Tl(201)-SPECT and all other MRI methods for predicting myocardial recovery after CABG.

To determine the value of fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for the detection of recurrent pancreatic cancer in comparison to computed tomography (CT) and magnetic resonance imaging (MRI).Thirty-one patients with suspected recurrence after surgery were included. Inclusion criteria were sudden weight loss, pain or increased CA 19-9 levels. FDG-PET was performed in all patients. After visual analysis, maximal standardized uptake values (SUVmax) were determined by placing regions of interest on the pancreas bed. Additionally, all patients underwent contrast-enhanced multidetector CT (n = 14) or MR (n = 17) imaging. Positive findings at FDG-PET or CT/MRI were compared to follow-up.All patients relapsed. Of 25 patients with local recurrences upon follow-up, initial imaging suggested relapse in 23 patients. Of these, FDG-PET detected 96% (22/23) and CT/MRI 39% (9/23). Local SUVmax ranged from 2.26 to 16.9 (mean, 6.06). Among 12 liver metastases, FDG-PET detected 42% (5/12). CT/MRI detected 92% (11/12) correctly. Moreover, 7/9 abdominal lesions were malignant upon follow-up of which FDG-PET detected 7/7 and CT/MR detected none. Additionally, FDG-PET detected extra-abdominal metastases in 2 patients.In patients suspected of pancreatic cancer relapse; FDG-PET reliably detected local recurrences, whereas CT/MRI was more sensitive for the detection of hepatic metastases. Furthermore, FDG-PET proved to be advantageous for the detection of nonlocoregional and extra-abdominal recurrences.

The objective was the evaluation of single photon emission computed tomography (SPECT) with integrated low dose computed tomography (CT) in comparison with a retrospective fusion of SPECT and high-resolution CT and a side-by-side analysis for lesion localisation in patients with neuroendocrine tumours. Twenty-seven patients were examined by multidetector CT. Additionally, as part of somatostatin receptor scintigraphy (SRS), an integrated SPECT-CT was performed. SPECT and CT data were fused using software with a registration algorithm based on normalised mutual information. The reliability of the topographic assignment of lesions in SPECT-CT, retrospective fusion and side-by-side analysis was evaluated by two blinded readers. Two patients were not enrolled in the final analysis because of misregistrations in the retrospective fusion. Eighty-seven foci were included in the analysis. For the anatomical assignment of foci, SPECT-CT and retrospective fusion revealed overall accuracies of 91 and 94% (side-by-side analysis 86%). The correct identification of foci as lymph node manifestations (n=25) was more accurate by retrospective fusion (88%) than from SPECT-CT images (76%) or by side-by-side analysis (60%). Both modalities of image fusion appear to be well suited for the localisation of SRS foci and are superior to side-by-side analysis of non-fused images especially concerning lymph node manifestations.

Ziel: Ziel der Studie war es, die Durchfuhrbarkeit und den klinischen Nutzen der retrospektiven Bildfusion (PET, SPECT, CT, MRT) in verschiedenen Korperregionen zu untersuchen. Material und Methode: In einer prospektiven Studie wurden insgesamt 273 Bildfusionen angefertigt. Die zugrunde liegenden Untersuchungen (CT, MRT, SPECT und PET) wurden jeweils in einer fur die Fragestellung und das Organsystem angemessenen Weise durchgefuhrt. Fur die digitale Bildfusion wurde eine im Rahmen der Studie entwickelte Software verwendet. Die Auswertung der Fusionen erfolgte nach der technischen Durchfuhrbarkeit, den unterschiedlichen klinischen Fragestellungen und der therapeutischen Relevanz. Ergebnisse: Die haufigsten Fusionskombinationen waren CT/PET (n = 156) und MRT/PET (n = 59), gefolgt von MRT/SPECT (n = 28), CT/SPECT (n = 22) und CT/MRT (n = 8). Die untersuchten Korperregionen umfassten dabei folgende Bereiche (mehrfache Nennungen moglich): Neurokranium (n = 42), Hals (n = 13), Lunge und Mediastinum (n = 24), Abdomen (n = 181) und Becken (n = 65). Technisch gelang die Bildfusion in 92,6 % der Falle (n = 253). Problematisch war die Bildfusion bei unterschiedlichen Korperhaltungen und bei Organen, die starken Bewegungen unterworfen sind. In 37,9 % der Falle konnten mit der Bildfusion klinisch relevante Zusatzinformationen gegenuber den Einzelmethoden erzielt werden. Schlussfolgerung: Bei Fragestellungen, die Leber, Pankreas, Rektum, Hals oder Neurokranium betreffen, kann die Bildfusion als etabliert angesehen werden. Bei den ubrigen Anwendungsgebieten limitieren Organbewegungen (beispielsweise im Bereich des Thorax) bislang den Routineeinsatz. Purpose: To evaluate the feasibility and the clinical benefits of retrospektive digital image fusion (PET, SPECT, CT and MRI). Materials and Methods: In a prospective study, a total of 273 image fusions were performed and evaluated. The underlying image acquisitions (CT, MRI, SPECT and PET) were performed in a way appropriate for the respective clinical question and anatomical region. Image fusion was executed with a software program developed during this study. The results of the image fusion procedure were evaluated in terms of technical feasibility, clinical objective, and therapeutic impact. Results: The most frequent combinations of modalities were CT/PET (n = 156) and MRI/PET (n = 59), followed by MRI/SPECT (n = 28), CT/SPECT (n = 22) and CT/MRI (n = 8). The clinical questions included following regions (more than one region per case possible): neurocranium (n = 42), neck (n = 13), lung and mediastinum (n = 24), abdomen (n = 181), and pelvis (n = 65). In 92.6 % of all cases (n = 253), image fusion was technically successful. Image fusion was able to improve sensitivity and specificity of the single modality, or to add important diagnostic information. Image fusion was problematic in cases of different body positions between the two imaging modalities or different positions of mobile organs. In 37.9 % of the cases, image fusion added clinically relevant information compared to the single modality. Conclusion: For clinical questions concerning liver, pancreas, rectum, neck, or neurocranium, image fusion is a reliable method suitable for routine clinical application. Organ motion still limits its feasibility and routine use in other areas (e. g., thorax).

Aim To determine the value of single photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT) for the interpretation of inconclusive foci in planar 1 3 1 I whole-body scans after radioiodine therapy. Methods Twenty-five patients with inconclusive findings in planar scanning after ablative radioiodine therapy (3.7 GBq 1 3 1 I) due to differentiated thyroid cancer were included. SPECT/CT of the region in question was performed with the Millennium VG Hawkeye (GE Medical Systems). SPECT with and without CT fusion were evaluated by two blinded independent nuclear medicine physicians in a consensus reading (including visual plausibility control). Each focus was judged according to its topographical assignment and clinical interpretation. With regard to therapeutic relevance, this information was evaluated in a focus based and patient based analysis. All evaluations used a binary ranking system. Focus assignments were compared to clinical and imaging follow-up. Results Forty-one lesions were observed in 25 patients. According to follow-up, 17/41 (41%) foci were caused by thyroid residue, 13/41 (32%) were caused by metastases, and 11/41 (27%) were not malignant. Of these foci, a SPECT/CT consensus reading assigned 39 (95%) correctly, as fused images of two foci did not pass the visual plausibility control (excluding one patient due to misregistration). For the remaining 39 foci, improved anatomical assignment by SPECT/CT was seen in 17/39 (44%) cases. Conclusions The changed interpretation of 15/39 (38%) foci would have been relevant for therapy in the focus based analysis. In the patient based analysis the information was still therapeutically relevant in 6/24 (25%) patients. Furthermore, plausibility control is also crucial in SPECT/CT image fusion in order to rule out artifacts.

The aim of this investigation was to compare two current non-invasive modalities, single photon emission tomography (SPECT) using 123-iodine-alpha-methyl tyrosine (123I-IMT) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) at 3.0 T, with regard to their ability to differentiate between residual/ recurrent tumors and treatment-related changes in patients pretreated for glioma. The patient population comprised 25 patients in whom recurrent glioma was suspected based on MR imaging. SPECT imaging started 10 min after iv. injection of 300-370 MBq 123I-IMT and was performed using a triple-head system. The IMT uptake was calculated semiquantitatively using regions-of-interest. 1H-MRS was performed at 3.0 T using the single-volume point-resolved spectroscopy (PRESS) technique. Guided by MR imaging volumes-of-interest for spectroscopy were placed into the suspected lesions. Signal intensities of choline-containing compounds (Cho), creatine and phosphocreatine (Cr), and N-acetylaspartate (NAA) were obtained. When using the cut-off of 1.62 for 123I-IMT uptake, the sensitivity, specificity, and accuracy of the 123I-IMT SPECT were 95, 100 and 96%, respectively. For 1H-MRS, the sensitivity, specificity and accuracy were 89, 83 and 88%, respectively, based both on the metabolic ratios of Cho/Cr and Cho/NAA as tumor criterion with cut-off values of 1.11 and 1.17, respectively. In conclusion, 123I-IMT SPECT yielded more favorable results compared to 1H-MRS at distinguishing recurrent and/or residual glioma from post-therapeutic changes and may be particularly valuable when the evaluation of tumor extent is necessary.