Search

Objectives: To evaluate the clinical spectrum and patterns of clinical presentation in congenital anomalies of kidney and urinary tract., Methods: We enrolled 307 consecutively presenting children with congenital anomalies of kidney and urinary tract at the pediatric nephrology clinic. Patients were evaluated clinically, with serum biochemistry, appropriate imaging and radionuclide scans., Results: The most common anomaly was primary vesicoureteric reflux (VUR) (87, 27.3%), followed by pelviureteral junction obstruction (PUJO) (62,20.1%), multicystic dysplastic kidney (51 16.6%), non-obstructive hydronephrosis (32, 10.4%) and posterior urethral valves (PUV) (23, 7.4%). 247 (80.4%) anomalies had been identified during the antenatal period. Another 33 (10.7%) were diagnosed during evaluation of urinary tract infection, and 21 (6.8%) during evaluation for hypertension at presentation. Obstructive anomalies presented earlier than non-obstructive (7 (3, 22.5) vs 10 (4, 24) mo: (P=0.01)). The median (IQR) ages of presentation for children with PUV (n=23), VUR (n=87) and PUJO (n=62) were 4 (2, 14) mo, 10 (5, 27) mo, and 7 (3, 22.5) mo, respectively. Nine (2.9%) children had extrarenal manifestations., Conclusions: The median age at clinical presentation for various subgroups of anomalies indicates delayed referral. We emphasize the need for prompt referral in order to initiate appropriate therapeutic strategies in children with congenital anomalies of kidney and urinary tract.

Background: Concern regarding overutilization of cardiac imaging has led to the development of appropriate use criteria (AUC). Myocardial perfusion imaging (MPI) is one of the most commonly used cardiac imaging modalities worldwide. Despite multiple iterations of AUC, there is currently no evidence regarding their real-world impact on population-based utilization rates of MPI. Our goal was to assess the impact of the AUC on rates of MPI in Ontario, Canada. We hypothesized that publication of the AUC would be associated with a significant reduction in MPI rates., Methods and Results: We conducted a retrospective cohort study of the adult population of Ontario from January 1, 2000, to December 31, 2015. Age- and sex-standardized rates were compared from 4 different periods intersected by 3 published iterations of the AUC. Overall, 3 072 611 MPI scans were performed in Ontario during our study period. The mean monthly rate increased from 14.1/10 000 in the period from January 2000 to October 2005 to 18.2/10 000 between November 2005 and June 2009. After this point in time, there was a reduction in rates, falling to a mean monthly rate of 17.1/10 000 between March 2014 and December 2015. Time series analysis revealed that publication of the 2009 AUC was associated with a significant reduction in MPI rates ( P <0.001). This translated into ≈88 849 fewer MPI scans at a cost savings of ≈72 million Canadian dollars., Conclusions: Our results reflect a potential real-world impact of the 2009 MPI AUC by demonstrating evidence of a significant effect on population-based rates of MPI., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background: Comparison of Latin American (LA) nuclear cardiology (NC) practice with that in the rest of the world (RoW) will identify areas for improvement and lead to educational activities to reduce radiation exposure from NC., Methods and Results: INCAPS collected data on all SPECT and PET procedures performed during a single week in March-April 2013 in 36 laboratories in 10 LA countries (n = 1139), and 272 laboratories in 55 countries in RoW (n = 6772). Eight "best practices" were identified a priori and a radiation-related Quality Index (QI) was devised indicating the number used. Mean radiation effective dose (ED) in LA was higher than in RoW (11.8 vs 9.1 mSv, p < 0.001). Within a populous country like Brazil, a wide variation in laboratory mean ED was found, ranging from 8.4 to 17.8 mSv. Only 11% of LA laboratories achieved median ED <9 mSv, compared to 32% in RoW (p < 0.001). QIs ranged from 2 in a laboratory in Mexico to 7 in a laboratory in Cuba. Three major opportunities to reduce ED for LA patients were identified: (1) more laboratories could implement stress-only imaging, (2) camera-based methods of ED reduction, including prone imaging, could be more frequently used, and (3) injected activity of 99m Tc could be adjusted reflecting patient weight/habitus., Conclusions: On average, radiation dose from NC is higher in LA compared to RoW, with median laboratory ED <9 mSv achieved only one third as frequently as in RoW. Opportunities to reduce radiation exposure in LA have been identified and guideline-based recommendations made to optimize protocols and adhere to the "as low as reasonably achievable" (ALARA) principle.

Aim: Updated presentation of the spectrum of nuclear medicine in-vivo examinations and therapies from officially available statistics on out-patient and in-patient care as well as trends of structural data on nuclear medicine in Germany., Methods: Data from the German Federal Health Monitoring, from the frequency statistics of the statutory health insurance for out-patients and from the German Medical Association were used and supplemented by data from selective literature searches., Results: In descending order, thyroid, bone and cardiac scans continue to be the most frequent nuclear medicine procedures. With a marked increase of PET/CT and SPECT/CT, the number of basic scintigraphies is declining. Cardiac, lung and brain scans as well as lymph scintigraphies are increasingly requested, bone and thyroid scan decrease. The consultation of nuclear medicine physicians in private practices is increasing by 4 % per year (2009: 2 164 664; 2015: 2 687 359). The number of nuclear medicine physicians in the out-patient sector rose significantly (2009: 756, 2015: 939, growth 24 %) and has remained constant due to restrictions since 2013. The specialist recognitions of women in nuclear medicine increased (proportion currently 46 %). In hospitals, more PET(/CT) scanners (2009: 97; 2015: 125) and fewer gamma cameras (2009: 594; 2015: 550) are operated. The number of non-thyroid (and also out-patient) radionuclide therapies continued to increase., Conclusion: With increased use of hybrid technologies, the nuclear medicine spectrum shows positive trends especially in nuclear cardiology and extra-thyroid therapy. These developments must be taken into account when amending regulations of specialist training and medical student teaching.

Sudden cardiac death (SCD) represents a significant portion of all cardiac deaths. Current guidelines focus mainly on left ventricular ejection fraction (LVEF) as the main criterion for SCD risk stratification and management. However, LVEF alone lacks both sensitivity and specificity in stratifying patients. Recent research has provided interesting data which supports a greater role for advanced cardiac imaging in risk stratification and patient management. In this article, we will focus on nuclear cardiac imaging, including left ventricular function assessment, myocardial perfusion imaging, myocardial blood flow quantification, metabolic imaging, and neurohormonal imaging. We will discuss how these can be used to better understand SCD and better stratify patient with both ischemic and non-ischemic cardiomyopathy.

Unlabelled: We sought to describe the practice of pediatric nuclear medicine at general hospitals in the United States and to assess the impact of dose awareness campaigns such as Image Gently., Methods: A web-based survey was developed that requested information regarding hospital type, whether the hospital practices pediatric nuclear medicine, and the hospital's method for determining the administered activity for children. The survey invitation was emailed to a sample of general hospitals with more than 300 beds, excluding dedicated pediatric, veterans, psychiatric, and rehabilitation hospitals. Data were collected for 5 procedures performed on children: (99m)Tc-methylene diphosphate (MDP) bone scans, (99m)Tc-mercaptoacetyltriglycine (MAG3) renograms, (99m)Tc-dimercaptosuccinic acid (DMSA) renal cortical scans, (99m)Tc-based hepatobiliary scans, and (18)F-FDG PET scans. The sites reported dosage by weight (MBq/kg), minimum and maximum dosages, and the activities that they would administer to 2 hypothetical patients: a 5-y-old boy (20 kg, 110 cm tall) and a 10-y-old girl (30 kg, 140 cm tall)., Results: The invitation was delivered to 196 sites, with 121 (61.7%) responding. Eighty-two hospitals (67.8%) performed nuclear medicine on children. All sites scaled administered activity for children, mostly by body weight. Also, 82.4% of sites indicated they were familiar with Image Gently, 57.1% were familiar with the 2010 North American consensus guidelines for children, and 54.9% altered their protocols because of the guidelines. The median value for parameters defined by the guidelines was equal to the guideline-recommended value for all procedures. More than 50% of the sites-particularly those familiar with the guidelines-were compliant with the guidelines regarding both the acquisition parameters and the administered activities for the 2 hypothetical patients. However, there remained a wide variation in practice, sometimes by more than a factor of 10, for sites not familiar with the guidelines., Conclusion: Image Gently and the North American guidelines have had a substantial impact on pediatric nuclear medicine practice in the United States. However, a wide variation in practice still exists, particularly for sites not familiar with the guidelines. Further promotion and dissemination of the guidelines and best practice are still necessary., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Unlabelled: Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PET-guided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between gated PET and CT. In this study, the effect of respiration-triggered CT on the spatial match between CT and amplitude-based respiration-gated PET images is investigated., Methods: (18)F-FDG PET/CT was performed in 38 patients. Images were acquired on 2 PET/CT scanners, one without and one with continuous bed motion during PET acquisition. The amplitude limits of the amplitude-based respiration-gated PET were used for the respiration-triggered sequential low-dose CT. Both standard (spiral) and triggered CT scans were used to reconstruct the PET data. Spatial mismatch was quantified using the position difference between the lung-liver boundary in PET and CT images, the distance between PET and CT lung lesions' centroids, and the amount of overlap of lesions indicated by the Jaccard similarity coefficient. Furthermore, the effect of attenuation correction was quantified by measuring SUVs in lung lesions., Results: For triggered CT, the average distance between the lung-liver boundary in PET and CT was significantly reduced (4.5 ± 6.7 mm) when compared with standard CT (9.2 ± 8.1 mm) (P < 0.001). The mean distance between the lesions' centroids in PET and CT images was 6.3 ± 4.0 and 5.6 ± 4.2 mm (P = 0.424), for the standard and triggered CT, respectively. Similarly, the Jaccard similarity coefficient was 0.30 ± 0.21 and 0.32 ± 0.20 (P = 0.609) for standard and triggered CT, respectively. For 6 lesions, there was no overlap of PET and CT when the standard CT was used; compared with the triggered CT, these lesions showed (partial) overlap. The maximum and mean SUV increase of the PET/CT compared with the PET/triggered CT was 5.7% ± 11.2% (P < 0.001) and 6.1% ± 10.2% (P = 0.001), respectively., Conclusion: Amplitude-based respiration-gated PET in combination with respiration-triggered CT resulted in a significantly improved match in the area of the liver dome and a significantly higher SUV for lung lesions. However, lesions in the lungs did not show a consistent improvement in spatial match., (© 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

The annual frequency of nuclear medicine examinations is increasing worldwide. This is partly a consequence of the recently introduced single photon emission tomography, combined with computed tomography, and positron emission tomography, combined with computed tomography, techniques, which combine functional, metabolic and morphological information important for the diagnosis of many diseases. However, since the effective radiation dose is the sum of the dose of two components, the hybrid examinations result in increased patient exposure. Accordingly, their justification becomes mandatory. It starts with their clinical importance-the opportunity to resolve a clinical problem decisive for patients' management. Knowledge of the indications, contraindications and the examinations' limitations is the responsibility of the nuclear medicine physician, as well as the choice of the most adequate examination and protocol. In conclusion, the cost and the accessibility of the examinations should not be the principal consideration as opposed to the diagnostic value and the exposure. Flexible protocols and algorithms should be used for hybrid nuclear medicine examinations., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The convenience of a computed tomography (CT) scanner in the emergency department (ED) may impact utilization rates. Our primary aim was to determine the rate of utilization before and after the placement of an ED CT scanner. Secondary aims were to determine the rate of utilization by anatomic region and during a 5-month period when the ED scanner was unavailable. We performed an electronic chart review of our ED with an annual census of 70,000 patients. We identified all patients over the age of 21 who had a CT scan performed from January 2008 to October 2010. Predetermined data elements were extracted by trained, hypothesis-blinded abstractors. Comparisons overall and within scan subtype were performed using seasonal matching. We found a CT utilization rate of 114 per 1,000 patient visits before and 139 per 1,000 patient visits after the placement of a CT scanner in the ED (p<0.0001). Linear regression analysis found a line with a slope of β=0.114 (95 % CI=0.107-0.121) and an R2 of 0.508. CT rates increased in the following regions: head CTs by 14 per 1,000 visits (p<0.0001); neck CTs by 3 per 1,000 visits (p<0.0001); abdomen/pelvis CTs by 4 per 1,000 visits (p=0.0015); "other" CTs by 2 per 1,000 visits (p<0.0001). Increased rates of chest and facial CTs approached significance with p values of 0.05. During the 5-month downtime, utilization remained unchanged at 141 per 1,000 visits (p=0.38). Overall CT utilization increased after the placement of a scanner in the ED. Most subtypes of scan increased. Utilization was unchanged during a period of ED scanner unavailability, suggesting that increased utilization may be difficult to reverse.

This manuscript presents the concerns around the increasingly common problem of not having readily available or useful "gold standard" measurements. This issue is particularly important in critical care where many measurements used in decision making are surrogates of what we would truly wish to use. However, the question is broad, important and applicable in many other areas.In particular, a gold standard measurement often exists, but is not clinically (or ethically in some cases) feasible. The question is how does one even begin to develop new measurements or surrogates if one has no gold standard to compare with?We raise this issue concisely with a specific example from mechanical ventilation, a core bread and butter therapy in critical care that is also a leading cause of length of stay and cost of care. Our proposed solution centers around a hierarchical validation approach that we believe would ameliorate ethics issues around radiation exposure that make current gold standard measures clinically infeasible, and thus provide a pathway to create a (new) gold standard.

Unlabelled: Impairment of GABA(A) receptor function is increasingly recognized to play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD) and schizophrenia (SZ)., Patients, Method: We conducted a PUBMED search, which provided a total of 23 in vivo investigations with PET and SPECT, in which GABA(A) receptor binding in patients with the primary diagnosis of AD (n = 14, 160 patients, 172 controls), MDD (n = 2, 24 patients, 28 controls) or SZ (n = 6, 77 patients, 90 controls) was compared to healthy individuals., Results: A retrospective analysis revealed that AD, MDD and SZ differed as to both site(s) and extent(s) of GABAergic impairment. Additionally, it may be stated that, while the decline of GABA(A) receptor binding AD involved the whole mesolimbocortical system, in SZ it was confined to the frontal and temporal cortex., Conclusion: As GABA is known to inhibit dopamine and serotonin, GABAergic dysfunction may be associated with the disturbances of dopaminergic and serotonergic neurotransmission in neuropsychiatric disorders.

Background: In primary hyperparathyreosis, US and scintigraphy are the most usual preoperative localization methods for detection of parathyroid adenomas or hyperplasia., Results: 88 (80 female) patients were detected. Unilateral neck exploration was performed in 43 patients (48.9 %) and bilateral exploration in 45 patients (51.1 %). The cure rate was 97.6 %. None case of parathyroid hyperplasia was detected, there were 2 cases of duplex adenoma. For left/right and quadrant localization, sensitivity of US was 71.05 % and 55.07 %, of scintigraphy 95.77 % and 88.71 %, and in concordant imaging 97.67 % and 96.77 %. Analogically, PPV was: US 91.53 % and 76.00 %, scintigraphy 87.18 % and 74.32 %, concordant imaging 93.33 %and 81.08 %. Only US sensitivity was significantly lower, all other differences showed no statistical significance., Conclusion: Our data showed low sensitivity but a high positive predictive value of ultrasonography and a high diagnostic value of scintigraphy. Sensitivity and the positive predictive value of concordant localization showed no significant difference, compared to scintigraphy. The routine need for concordance for parathyroid adenoma localization appears dubious, however, its value for prediction of multiglandular disease remains important for protocols that do not apply peroperative localization (Tab. 2, Ref. 35).

Background: Preoperative imaging for early-stage cutaneous melanoma is not recommended by current guidelines. Our goal was to investigate our institutional usage and utility., Methods: Patients with clinically node-negative cutaneous melanoma undergoing surgery with sentinel lymph node biopsy were identified retrospectively. Any melanoma-related imaging after diagnosis and before surgery was considered a staging study., Results: Five hundred fifteen studies were performed in 409 of 546 (75%) patients. Chest x-rays was performed in 70% and advanced imaging in 14% (computed tomography imaging, magnetic resonance imaging, ultrasound, and positron-emission computed tomography imaging). No metastatic lesions were identified. A Breslow thickness greater than 4 mm (odds ratio = 6.46 vs <1 mm; 95% confidence interval, 2.07 to 20.15) and male sex (odds ratio = 2.62 vs female; 95% confidence interval, 1.26 to 5.46) were associated with an increased likelihood of advanced imaging., Conclusions: Preoperative imaging was performed in the majority of patients with node-negative melanoma, with 14% undergoing advanced studies. No metastatic lesions were identified, confirming the limited utility in this setting., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Mediastinal lymph node metastases (MLNM) from differentiated thyroid carcinoma (DTC) are considered difficult to diagnose. The aim of this study was to assess the value of iodine-131 (131I) single photon emission tomography/computed tomography (SPET/CT) and of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for the diagnosis of MLNM from DTC. Five hundred and eleven consecutive patients operated for DTC and treated with 131I for ablation of the remnant thyroid and/or for treatment of metastases were enrolled in the study and underwent an 131I whole body scan (131I-WBS). Thirty seven sites of increased 131I uptake, on the 131I-WBS that could be an indication for MLNM were re-evaluated by a 131I-SPET/CT scan. Thirty four other patients with negative 131I-WBS but having elevated serum thyroglobulin (Tg), were examined by 18F-FDG PET/CT to possibly diagnose MLNM. A total of 44 DTC patients with MLNM were identified, among the above 37 and 34 cases: 25/37 (67.6%) cases were examined and identified by 131I-SPET/CT and 19/34 (55.9%) cases by 18F-FDG PET/CT. A total of 25 and 19 cases were identified. The male-to-female ratio and the average age in patients with 18F-FDG-avid MLNM were significantly higher than in patients with 131I-avid MLNM. Among the above 44 patients, 40 patients had superior mediastinal nodal metastases, 9 had aortic nodal metastases and only 1 inferior mediastinal nodal metastases. A patient could have metastases in more than one site. In conclusion, our study suggests that in 511 operated DTC patients, treated for remnant ablation and/or for metastases and examined by 131I-WBS, there were 37 cases doubtful of having MLNM in the 131I-WBS and 34 cases doubtful, because of negative 131I-WBS and elevated Tg. The 131I-SPET/CT scan was sensitive for detecting MLNM in 25 of the 37 cases and the 18F-FDG PET/CT in 19 of the 34 cases. These hybrid imaging modalities, when applied as above, were suitable for detecting more MLNM and thus, better supporting treatment planning in these DTC patients.

Background: Urological investigation in children frequently involves high radiation doses; however, the issue of radiation for these investigations receives little attention compared with CT., Objective: To compare the radiation dose from paediatric urological investigations with CT, which is commonly regarded as the more major source of radiation exposure., Materials and Methods: We conducted a retrospective audit in a tertiary paediatric centre of the number and radiation dose of CT scans, micturating cystourethrography exams and urological nuclear medicine scans from 2006 to 2011. This was compared with radiation doses in the literature and an audit of the frequency of these studies in Australia., Results: The tertiary centre audit demonstrated that the ratio of the frequency of urological to CT examinations was 0.8:1 in children younger than 17 years. The ratio of the radiation dose of urological to CT examinations was 0.7:1. The ratio in children younger than 5 years was 1.9:1. In Australia the frequency of urological procedures compared with CT was 0.4:1 in children younger than 17 years and 3.1:1 in those younger than 5 years. The ratio of radiation-related publications was 1:9 favouring CT., Conclusion: The incidence and radiation dose of paediatric urological studies is comparable to those of CT. Nevertheless the radiation dose of urological procedures receives considerably less attention in the literature.

We have developed a fast, user friendly, ray-tracing program, "CSIM" for low-energy gamma rays (up to ∼200keV) to simulate the performance characteristics of parallelhole collimators. We have used a ray-tracing approach to find the sensitivity and resolution of the parallelhole collimator by including the penetration of photons through the collimator due to the finite attenuation of the collimator material. "CSIM" can calculate the sensitivity of the collimator, the geometric and penetrating photon ratios, and the 1D and 2D point source response functions (PSF) with the statistical uncertainty for different hole shapes (e.g. square, hexagonal, and cylindrical). We have used "CSIM" to simulate the collimator of the YAP-(S)PETII small animal scanner. We present the analysis of the YAP-(S)PETII scanner round-hole parallel collimator designed for nuclear medicine imaging at 140keV. For this aim, different designs have been considered for a variety of source-collimator distances (b=5, 10, 15, 20cm). Resolution and sensitivity characteristics have been plotted as a function of the collimator thickness and the diameter of the hole. For each value of the source-collimator distance, and for each collimator thickness investigated, the trade-off between sensitivity and spatial resolution has been given as a series of characteristic curves. Then, we compare our simulated resolution and sensitivity results to the analytically calculated ones and found that the analytically calculated results for the YAP-(S)PETII scanner collimator are not far away the results predicted by CSIM and also with the experimentally measured resolution values., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Evidence-based guidelines recommend limited perioperative diagnostic imaging for new breast cancer diagnoses. For patients aged >65 years, conventional imaging use (mammography, plain radiographs, and ultrasound) has remained stable, whereas advanced imaging (computed tomography [CT], nuclear medicine scans [positron emission tomography/bone scans], and magnetic resonance imaging [MRI]) use has increased. In this study, the authors evaluated traditional and advanced imaging use among younger patients (aged ≤ 65 years) undergoing breast cancer surgery., Methods: The MarketScan Commercial Claims and Encounters Research Database from 2005 through 2008 was analyzed to evaluate the use of conventional and advanced diagnostic imaging associated with surgery for ductal carcinoma in situ (DCIS) or stage I through III invasive breast cancer., Results: The study cohort included 52,202 women (13% with DCIS and 87% with stage I-III breast cancer). The proportion of patients undergoing conventional imaging remained stable, whereas the average number of conventional imaging tests per patient increased from 4.21 tests in 2005 to 4.79 tests per patient in 2008 (P < .0001). For advanced imaging, the proportion of women who underwent imaging increased from 48.8% in 2005 to 68.8% in 2008 (P < .0001), as did the number of tests per patient (from 1.53 tests in 2005 to 1.98 tests in 2008; P < .0001). MRI examinations accounted for nearly all of the increase in advanced imaging. Patients who underwent MRI examinations received significantly more traditional imaging tests compared with to those who did not, indicating that these tests are additive and are not replacing traditional imaging., Conclusions: The current results demonstrate that the use of perioperative breast MRI has increased among women aged <65 years. Further study is indicated to determine whether the benefits of this procedure justify increased use., (Copyright © 2012 American Cancer Society.)

Background: Although differences in the rate of utilization of invasive cardiac procedures between Veterans Affairs (VA) hospitals and other health care systems are present, noninvasive cardiac imaging use pattern has not been well studied. We evaluated the ability of the updated appropriateness use criteria (AUC) to determine utilization patterns of myocardial perfusion imaging (MPI) and compare use between an academic practice and a VA., Methods: One-hundred fifty stress/rest MPI studies in an academic practice and 150 at a VA hospital were retrospectively reviewed using the hierarchical approach published in the 2009 AUC., Results: Less than 1% of studies were unclassified. A higher percentage of MPI were requested for inappropriate reason at the VA, although this difference was not statistically significant (P = .248). In the VA, non-physicians requested significantly more inappropriate studies than physicians (26.8% vs 20.1%; P < .048). Within the academic practice non-cardiologists referred more patients for inappropriate indications than cardiologists (23.9% vs 10.1%; P = .001). Five most common inappropriate indications accounted for the vast majority of inappropriately requested MPI (77%)., Conclusions: The revised 2009 AUC allow for near complete categorization of appropriateness in testing. Differences between institutions and provider types were noted and areas for improved utilization were identified.

Radioligand positron emission tomography (PET) with dual scan paradigms can provide valuable insight into changes in synaptic neurotransmitter concentration due to experimental manipulation. The residual t-test has been utilized to improve the sensitivity of the t-test in PET studies. However, no further development of statistical tests using residuals has been proposed so far to be applied in cases when there are more than two conditions. Here, we propose the residual f-test, a one-way analysis of variance (ANOVA), and examine its feasibility using simulated [(11)C]raclopride PET data. We also re-visit data from our previously published [(11)C]raclopride PET study, in which 10 individuals underwent three PET scans under different conditions. We found that the residual f-test is superior in terms of sensitivity than the conventional f-test while still controlling for type 1 error. The test will therefore allow us to reliably test hypotheses in the smaller sample sizes often used in explorative PET studies.

Purpose: The aim of this study was to examine growth trends in ownership or leasing of private-office PET scanners by nonradiologist physicians., Materials and Methods: The Medicare Part B Physician/Supplier Procedure Summary Master Files for 2002 through 2007 were used to collect the following data for each PET-related Current Procedural Terminology((R)) code: 1) annual procedure volume, 2) places of service for the procedures, and 3) specialties of the physicians filing the claims. To determine ownership or leasing, only technical and global claims that occurred in the nonhospital, private-office setting were included in the study. Professional component-only claims were not included. Procedure volume and growth trends were compared between radiologists and other specialties., Results: Between 2002 and 2007, radiologist-owned Medicare PET scans increased by 259%, whereas nonradiologist-owned or nonradiologist-leased scans grew by 737%. Five specialty groups accounted for 95% of all nonradiologist PET volume in 2007: internal medicine subspecialties (28,324 studies in 2007), medical oncology (14,320 studies), cardiology (13,724 studies), radiation oncology (9,563 studies), and primary care (2,398 studies). In 2002, of all Medicare PET examinations performed on units owned or leased by physicians, the share for nonradiologists was 13%; their share rose to 24% in 2007., Conclusion: Although a large percentage of PET scans in private offices are done by radiologists, the growth rate among nonradiologists was far higher between 2002 and 2007 (259% for the former, 737% for the latter). The disproportionately rapid growth of PET scans performed on units owned by nonradiologists raises concern about self-referral at a time when policymakers are struggling to contain costs and reduce radiation exposure.

Purpose: Multimodality imaging represents an area of rapid growth with important professional implication for both nuclear medicine physicians and radiologists throughout Europe. As a preliminary step for future action aimed at improving the quality and accessibility of PET/SPECT/CT multimodality imaging practice in Europe, the European Association of Nuclear Medicine (EANM) and the European Society of Radiology (ESR) performed a survey among the individual membership of both societies to obtain information on the status of multimodality imaging in their facilities and their future visions on training for combined modalities., Methods: A questionnaire was forwarded to all individual members of the EANM and ESR. The main subject matter of the questionnaire related to: (1) study performance,current procedures, current equipment including its supervisory personnel at respondents' individual facilities and (2)vision of future practice, performance and the potential for combined interdisciplinary viewing and training for future professionals., Results: The reporting and the billing procedures of multimodality imaging studies are very heterogeneous in European countries. The majority of the members of both societies believe that the proportion of PET/CT conducted as a full diagnostic CT with contrast enhancement will increase over time. As expected, (18)F-FDG is the most commonly used PET tracer for clinical applications. The large majority of respondents were in favour of an interdisciplinary training programme being developed on a European level together by the EANM and the ESR and the respective sections of the European Union of Medical Specialists., Conclusion: The results of this survey show that there is wide heterogeneity in the current practice of multimodality imaging in Europe. This situation may limit the full potential and integration of multimodality imaging within the clinical arena. There is a strong desire within both specialties for the development of interdisciplinary training to address some of these issues.

Objective: The purpose of the study was to study factors affecting SUV of PET imaging with 18F-FDG., Material and Method: PET/CT Biograph 64 was used to acquire the data. A NEMA PET phantom with 6 spheres varying in diameter from 10 to 37 mm was used to mimic the human body and tumors. Background activity of 18F in the phantom was 0.14 microCi/ml and tumor-to-background ratios (TBR) of 2:1, 5:1 and 10:1 were studied. For each TBR, thirty sinograms were acquired with 3-min scan durations. Different scan durations varying from 3 to 20 min using a TBR of 5:1 were studied and three datasets of each scan time were collected Sinograms were reconstructed using the Ordered Subset Expectation Maximization (OSEM) algorithm with 5 mm Full-Width-at-Half-Maximum (FWHM) Gaussian filtering. Sinograms at TBR of 5:1 were reconstructed by varying the number of iterative updates of OSEM (N) from 8 to 168 and SUVavg and SUVmax were measured. The percentage of underestimation of SUVs was used to study the effect of tumor size and TBR. Intraclass correlation coefficient (ICC) was used to test the reliability of SUVmax with different scan durations., Results: The results showed that both the SUVavg and SUVmax rapidly increased when N was <48 and slightly increased afterwards. At TBRs ranging from 2:l to 10:1, the percentages of underestimation of SUVmax ranged from 8.17 to 22.46 and that of SUVavg were ranged from 41.44 to 52.33 for 37-mm sphere and from 40.38 to 54.52 and from 48.97 to 67.73 for 10-mm sphere respectively. Different scan durations gave reliable SUVs(max) with ICC of 0.996., Conclusion: SUVs increased as N increased The percentage of underestimation of the SUV depended on tumor size and TBR. Scan duration did not affect SUVs.

This review highlights and compares risk assessment, predictive accuracy, and economic outcomes for 3 commonly applied cardiac imaging procedures: stress myocardial perfusion SPECT or PET and coronary CT angiography (CCTA). This review highlights an expansive evidence base for stress myocardial perfusion imaging and reveals a decided advantage for higher-risk patients, notably those who have established coronary artery disease (CAD). It is likely that the use of CCTA will continue to expand, particularly for patients with more atypical symptoms and patients with a lower likelihood of CAD. Despite a high level of evidence, comparative research is not available across modalities that could definitively drive utilization of cardiac imaging modalities.

Purpose: The aim of this study was to examine the effects of self-referral by comparing recent trends in payments and utilization rates for radionuclide myocardial perfusion imaging (MPI) among radiologists and cardiologists between 1998 and 2006., Materials and Methods: Nationwide Medicare Part B claims databases for 1998 through 2006 were used. The 4 primary MPI codes were selected. Using Medicare's physician specialty codes, physician providers were identified as radiologists, cardiologists, or other physicians. Payments for MPI to the 3 groups were tracked over the study period. Trends in utilization rates in both hospital and private office settings were also compared among the 3 groups. In addition, utilization trends were studied for related procedures, such as stress echocardiography (SE) and invasive diagnostic coronary angiography (CA)., Results: Between 1998 and 2006, Medicare Part B payments to radiologists for MPI increased from $72.6 million to $84.0 million (+16%), while among cardiologists, payments increased from $242.6 million to $972.0 million (+301%). Private office utilization rates per 1,000 Medicare beneficiaries increased by 215% among cardiologists, compared with 32% among radiologists. In hospital settings, the rate changes were much more modest. Hospital utilization rates were consistently higher among radiologists than cardiologists; in hospital settings in 2006, the rate was 15.3 per 1,000 among radiologists, compared with 11.8 per 1,000 among cardiologists. Between 1998 and 2006, the utilization rate for SE among cardiologists increased by 20%, and the rate for diagnostic CA among cardiologists also increased by 20%., Conclusion: In recent years, there have been very sharp increases in the costs and utilization of MPI among cardiologists compared with radiologists. Most of the growth occurred in cardiologists' private offices. In hospital settings, radiologists still do more MPI examinations than cardiologists. Because MPI is a highly reimbursed procedure and there is no evidence that coronary disease is increasing in frequency in the Medicare population, this trend raises a concern about inappropriate self-referral. This is particularly true in view of the facts that the utilization of a competing procedure such as SE also continues to increase among cardiologists and that MPI is not substituting for an invasive procedure such as diagnostic CA.

Background: Radioactive iodine is useful in the diagnosis and treatment of patients with newly diagnosed thyrotoxicosis. However, in many patients these tests are not possible to obtain due to recent administration of iodinated contrast for other types of diagnostic studies, most frequently computed tomography (CT) scans., Objective: To determine the frequency of iodinated contrast use in hospital inpatients newly diagnosed with thyrotoxicosis and the utility of these studies., Design: Retrospective chart review., Setting: Academic medical center., Intervention: None., Patients: Inpatients with newly diagnosed thyrotoxicosis who were seen in consultation by the endocrinology service., Measurements: The records of inpatient endocrinology consultations (n = 1171) performed by our service over a 4-year period were reviewed. Records of patients with newly diagnosed thyrotoxicosis were identified and reviewed to determine if iodinated contrast had been recently administered, the types of studies it was used for, and the results of those studies., Results: Forty-five patients (45%) had been given iodinated contrast within 2 weeks prior to endocrinology evaluation, 43 for CT scanning, and 2 for angiography. Of the patients who underwent CT scanning, 7 (16%) had a finding that potentially changed their inpatient management. Only 1 of these patients required emergent treatment of a condition diagnosed by CT scan before further diagnostic studies could have been performed., Conclusions: A substantial number of inpatients with thyrotoxicosis receive iodinated contrast prior to endocrinologic evaluation. Acute findings from these studies that change patient management are uncommon. Awareness of this issue may facilitate care of hospitalized patients with thyrotoxicosis., ((c) 2009 Society of Hospital Medicine.)

Aim: To evaluate the clinical usefulness of (18)F-fluorodeoxyglucose positron emission and computed tomography ((18)F-FDG PET/CT) in restaging of esophageal cancer after surgical resection and radiotherapy., Methods: Between January 2007 and Aug 2008, twenty histopathologically diagnosed esophageal cancer patients underwent 25 PET/CT scans (three patients had two scans and one patient had three scans) for restaging after surgical resection and radiotherapy. The standard reference for tumor recurrence was histopathologic confirmation or clinical follow-up for at least ten months after (18)F-FDG PET/CT examinations., Results: Tumor recurrence was confirmed histopathologically in seven of the 20 patients (35%) and by clinical and radiological follow-up in 13 (65%). (18)F-FDG PET/CT was positive in 14 patients (68.4%) and negative in six (31.6%). (18)F-FDG PET/CT was true positive in 11 patients, false positive in three and true negative in six. Overall, the accuracy of (18)F-FDG PET/CT was 85%, negative predictive value (NPV) was 100%, and positive predictive value (PPV) was 78.6%. The three false positive PET/CT findings comprised chronic inflammation of mediastinal lymph nodes (n = 2) and anastomosis inflammation (n = 1). PET/CT demonstrated distant metastasis in 10 patients. (18)F-FDG PET/CT imaging-guided salvage treatment in nine patients was performed. Treatment regimens were changed in 12 (60%) patients after introducing (18)F-FDG PET/CT into their conventional post-treatment follow-up program., Conclusion: Whole body (18)F-FDG PET/CT is effective in detecting relapse of esophageal cancer after surgical resection and radiotherapy. It could also have important clinical impact on the management of esophageal cancer, influencing both clinical restaging and salvage treatment of patients.

Objective: The Subcommittee on the Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to provide detailed information on its present status., Methods: Questionnaires were sent to all institutions known to the Japan Radioisotope Association to conduct nuclear medicine examinations. The questionnaires addressed the number and kind of nuclear medicine examinations performed as well as the kind and dose of the radiopharmaceuticals used during the month of June 2007. The annual number of total or specific examinations was then estimated., Results: Of the institutions sent questionnaires, 1219 were for in vivo study, 49 for in vitro study, and 212 for positron emission tomography (PET) study. Of these, 92.2% provided answers. A total of 1569 gamma cameras were installed in 1119 institutions, of which 70% were dual-head cameras. The estimated total annual number of in vivo examinations expressed by the number of administered radiopharmaceuticals was 1.41 million, representing a decrease of 11.5% when compared with that of the previous survey (2002). The frequency of study with respect to single-photon emission computed tomography (SPECT) slightly increased to 42.3% from 39.9% in the previous survey. The most frequently performed scintigraphy was bone (38.3%), followed by myocardium (26.2%) and brain perfusion (14.1%). Brain perfusion scintigraphy slightly increased, whereas tumor scintigraphy decreased by one-half when compared with the previous survey. The most commonly used radiopharmaceutical for each scintigraphy was (99m)Tc-HMDP for bone, thallium-201 ((201)Tl)-chloride for myocardium, gallium-67 ((67)Ga)-citrate for tumor, and technetium-99m-ethylcysteinate dimmer ((99m)Tc-ECD) for brain. The number of PET institutes increased from 36 to 212. (18)F-fluorodeoxyglucose ((18)F-FDG)-PET dramatically increased 14.8-fold during the past 5 years. Radionuclide therapy also increased. (131)I therapy for thyroid cancer and hyperthyroidism was conducted yearly in 2373 and 4146 patients, respectively. A total of 13.1 million in vitro radioassays were carried out yearly, the number of which has been decreasing continuously since 1992., Conclusions: It was proved that the content of nuclear medicine practice in Japan has changed considerably in the past 5 years. Namely, (18)F-FDG-PET and radionuclide therapy increased. This report might be useful for understanding the present trends of nuclear medicine practice in Japan.

For positron emission tomography (PET) imaging, different reconstruction methods can be applied, including maximum likelihood (ML ) and maximum a posteriori (MAP) reconstruction. Postsmoothed ML images have approximately position and object independent spatial resolution, which is advantageous for (semi-) quantitative analysis. However, the complex object dependent smoothing obtained with MAP might yield improved noise characteristics, beneficial for lesion detection. In this contribution, MAP and postsmoothed ML are compared for hot spot detection by human observers and by the channelized Hotelling observer (CHO). The study design was based on the "multiple alternative forced choice" approach. For the MAP reconstruction, the relative difference prior was used. For postsmoothed ML, a Gaussian smoothing kernel was used. Both the human observers and the CHO performed slightly better on MAP images than on postsmoothed ML images. The average CHO performance was similar to the best human performance. The CHO was then applied to evaluate the performance of priors with reduced penalty for large differences. For these priors, a poorer detection performance was obtained.

Unlabelled: Universally applied standards for administering radiopharmaceutical doses in children do not presently exist. Hence, pediatric radiopharmaceutical dosimetry varies considerably from institution to institution and is generally based on the recommended adult dose adjusted for body mass., Methods: We surveyed 13 pediatric hospitals in North America to obtain objective data on dosimetry practices for 16 pediatric nuclear medicine examinations, including the minimum total radiopharmaceutical administered dose per examination, the total administered dose based on body mass, and maximum total doses in children., Results: The reported administered doses of radiopharmaceuticals to children vary over a relatively large range, especially with respect to minimum total administered doses., Conclusion: This survey has identified a broad range of administered doses directly leading to variability in radiation-absorbed doses to patients. The nuclear medicine community should develop pediatric standards for radiopharmaceutical administered doses and reduce radiation exposure in children, such as through the use of modern software reconstruction techniques.

Objective: To evaluate the status of nuclear medicine in Beijing during 2005., Methods: For evaluating the status, a survey was performed in September 2006 by postal questionnaires. Forty-two nuclear medicine departments in Beijing were investigated regarding staff, equipment and clinical applications., Results: Up to January 2007, thirty nuclear medicine departments had responded to our survey (response rate, 71.4%). These departments employed a total of 321 staff (141 physicians, 122 technicians, seven physicists, 22 nurses and 29 other staff) and were equipped with 47 scanners (42 SPECT, three PET, two PET/CT) before September 2006. During 2005, these departments completed 88 135 scans (84 734 SPECT, 3401 PET), 462 246 radioimmunoassays and 2228 radioisotope treatment (1288 Graves' disease, 268 thyroid cancer, 166 bone metastasis, 506 other). Furthermore, eight major hospitals hired more highly qualified staff with greater experience, such as professors or associate professors, and who had more clinical applications than did non-majors. The percentage of the departments that conducted daily and monthly quality control procedures was 43.3% and 40.0%, respectively., Conclusion: Nuclear medicine departments in Beijing are on a considerable scale, but still have a long way to go in order to be well developed. Hospitals in Beijing should increase the number of physicists and perform QA/QC procedures more frequently.

Aim: This second survey was to deliver further information on myocardial perfusion scintigraphy (MPS) in Germany in 2006., Method: 351 questionnaires were evaluated: 207 private practices (PP), 117 hospitals (HO), 27 from university hospitals (UH)., Results: MPS of 106 331 patients were reported, 85% were investigated with (99m)Tc-perfusion tracers. 74% [2005 = 72%] were performed in PP, 17% [2005 = 15%] in HO and 9% [2005 = 13%] in UH. PP, which participated in 2005 and 2006, demonstrated an increase by 3,9% (HO 0%, UH - 13,0%). The type of stress was pharmacological in 27% [2005 = 22%]; 54% adenosine (of these 29% with exercise), 37% dipyridamole (of these 56% with exercise), and 9% dobutamine. Gated SPECT was performed in 42% [2005 = 36%] of all rest- and in 39% [2005 = 32%] of all stress MPS. An attenuation correction was used by 69 [2005 = 78] institutions. 40% of all MPS were performed in patients suspected to have CAD. 24% of all institutions reported changes in the use of MPS by competing methods., Conclusion: There is a small increase of MPS between 2005 and 2006 despite competing methods. Gated SPECT has experienced more acceptance. Suspicion of CAD is an important indication of MPS. In order to tap the full potential of MPS a gated SPECT should be performed routinely.

Our goal is to optimize regularized image reconstruction for emission tomography with respect to lesion detectability in the reconstructed images. We consider model observers whose decision variable is the maximum value of a local test statistic within a search area. Previous approaches have used simulations to evaluate the performance of such observers. We propose an alternative approach, where approximations of tail probabilities for the maximum of correlated Gaussian random fields facilitate analytical evaluation of detection performance. We illustrate how these approximations, which are reasonably accurate at low probability of false alarm operating points, can be used to optimize regularization with respect to lesion detectability.

A prospective study was conducted to examine clinical practices in the management of head-injured patients preinception and postinception of the Scottish Intercollegiate Guidelines Network guidelines. Comparison was made between the Scottish Intercollegiate Guidelines Network and National Institute for Clinical Excellence guidelines on their indications for computed tomography scanning. Information was available on 2827 adult patients. Two hundred and thirty-two patients satisfied one or more Scottish Intercollegiate Guidelines Network criteria for computed tomography scanning. Four hundred and seventy-eight patients fulfilled one or more National Institute for Clinical Excellence criteria for scanning. No patient with Scottish Intercollegiate Guidelines Network or National Institute for Clinical Excellence indications for computed tomography scanning and who was not scanned, subsequently required neurosurgical treatment for a complication related to their injury. Full compliance with the scanning recommendations in the Scottish Intercollegiate Guidelines Network and National Institute for Clinical Excellence guidelines will require a significant increase in scanning resource and is unlikely to lead to the identification of a significant additional number of patients with intracranial lesions requiring neurosurgical intervention.

Introduction: The objectives were to demonstrate the extra workload for emergency medicine of inpatient management of mild/moderate head injuries and to determine the effectiveness of current computed tomography guidelines., Method: A retrospective study of head injuries presenting to St James's Hospital Dublin, where the Galasko report has been implemented since 2001. We studied injuries presented from January 2001 to January 2002. Length of stay, mechanism of injury, follow-up, indication for admission and computed tomography scan were identified., Results: A total of 2281 patients presented with head injury as their first or second triage complaint. One hundred and twenty-three patients were admitted to the emergency ward, of which 34 had computed tomography investigation. Ten computed tomography scans demonstrated intracranial injury. Intracranial injury was associated with vomiting, Glasgow coma score 14 (confusion), deterioration of Glasgow coma score, clinical basilar skull fracture and alcohol-related falls. The average length of stay for patients admitted to observation ward was 2.3 days and 5 days for those who had a brain injury on computed tomography scan., Conclusions: Implementation of the Galasko report has resource, manpower and training implications for emergency medicine. The current computed tomography guidelines should be modified to include Glasgow coma score<15 and neurological symptoms for example, vomiting and alcohol-related falls.

This paper reviews the situation of nuclear medicine in Central and Eastern Europe (CEE), i.e. a group of 15 countries lying east of the Oder river-Trieste line and west of the present/planned EU eastern border. Together these countries have 106.6 million inhabitants, i.e. about a quarter of the population of the "European economic space". Its nuclear medicine, however, represents less than 10% of European nuclear medicine manpower and equipment. In these countries there are at least 245 nuclear medicine departments with 661 nuclear medicine specialists and at least 376 gamma cameras. There are six dedicated PET units and three PET/SPECT centres, as well as one manufacturer of gamma cameras, six radiopharmaceutical manufacturers and two nuclear medicine scientific journals. The biggest nuclear medicine communities are in the Czech Republic, Hungary and Poland. The scientific input of the CEE countries to European science is moderate-about 10% when measured by EANM congress abstracts, and 5% when measured by the number of papers in MEDLINE-indexed journals. Mean European bibliometric parameters are approached only by Hungary and-to some extent-the Czech Republic. This survey indicates the need for international cooperation to improve the level of nuclear medicine in the CEE countries so that it reaches European standards. The potential of these countries could also be better used to the benefit of European nuclear medicine.

Background: The second survey of nuclear cardiology in the Czech Republic was conducted to ascertain whether the activity had increased since the first survey in 2001; we also intended to identify new trends in clinical practice., Materials and Methods: All 46 departments of nuclear medicine in the Czech Republic completed a questionnaire concerning nuclear cardiology activity in 2002-2003 and current clinical and technical practices., Results: There were 66 SPET cameras in 2003 in comparison with 54 SPET cameras in 2001. Of the 46 centres, 39 (85%) provided nuclear cardiology service. The total number of cardiac studies was 19,261 in 2003 (i.e. 1.9 studies/1,000 population; myocardial perfusion imaging (MPI) studies accounted for 91.3% of total nuclear cardiology. In 2001-2003, the utilization rate of MPI increased annually by 10%, 13% and 21% respectively. Twenty-six departments (67%) reported that the number of MPI had increased. The utilization of gated SPET method showed a very positive trend; as only 39% of all MPI studies were acquired using ECG-gating in 2001, but in 2003, there was an increase to 61%. We observed no increase in utilization of attenuation correction (3 centres in 2003 in comparison with 5 centres in 2001). Despite new PET capacity in the Czech Republic, the total number of FDG cardiology studies was somewhat lower in 2003 than in 2001 (155 compared with 163 studies)., Conclusions: Our data documented substantial growth in the number of MPI examinations in 2001-2003. However, Czech Republic nuclear cardiology activity still remained below the European average (2.2 studies/1,000 population in 1994); a further increase in MPI activity is necessary to adequately support the needs of cardiac patients.

Objective: Alcohol and other drugs of abuse stimulate dopamine release in the ventral striatum, which includes the nucleus accumbens, a core region of the brain reward system, and reinforce substance intake. Chronic alcohol intake is associated with down-regulation of central dopamine D(2) receptors, and delayed recovery of D(2) receptor sensitivity after detoxification is positively correlated with high risk for relapse. Prolonged D(2) receptor dysfunction in the ventral striatum may interfere with a dopamine-dependent error detection signal and bias the brain reward system toward excessive attribution of incentive salience to alcohol-associated stimuli., Method: Multimodal imaging, with the radioligand [(18)F]desmethoxyfallypride and positron emission tomography as well as functional magnetic resonance imaging (fMRI), was used to compare 11 detoxified male alcoholics with 13 healthy men. The authors measured the association of D(2)-like dopamine receptors in the ventral striatum with alcohol craving and central processing of alcohol cues., Results: Activation of the medial prefrontal cortex and striatum by alcohol-associated stimuli, relative to activation by neutral visual stimuli, was greater in the detoxified alcoholics than in the healthy men. The alcoholics displayed less availability of D(2)-like receptors in the ventral striatum, which was associated with alcohol craving severity and with greater cue-induced activation of the medial prefrontal cortex and anterior cingulate as assessed with fMRI., Discussion: In alcoholics, dopaminergic dysfunction in the ventral striatum may attribute incentive salience to alcohol-associated stimuli, so that alcohol cues elicit craving and excessive activation of neural networks associated with attention and behavior control.

Purpose: To measure vagus nerve stimulation (VNS)-induced cerebral blood flow (CBF) effects after prolonged VNS and to compare these effects with immediate VNS effects on CBF., Methods: Ten consenting partial epilepsy patients had positron emission tomography (PET) with intravenous [15O]H2O. Each had three control scans without VNS and three scans during 30 s of VNS, within 20 h after VNS began (immediate-effect study), and repeated after 3 months of VNS (prolonged study). After intrasubject subtraction of control from stimulation scans, images were anatomically transformed for intersubject averaging and superimposed on magnetic resonance imaging (MRI) for anatomic localization. Changes on t-statistical maps were considered significant at p < 0.05 (corrected for multiple comparisons)., Results: During prolonged studies, CBF changes were not observed in any regions that did not have CBF changes during immediate-effect studies. During both types of studies, VNS-induced CBF increases were similarly located in the bilateral thalami, hypothalami, inferior cerebellar hemispheres, and right postcentral gyrus. During immediate-effect studies, VNS decreased bilateral hippocampal, amygdalar, and cingulate CBF and increased bilateral insular CBF; no significant CBF changes were observed in these regions during prolonged studies. Mean seizure frequency decreased by 25% over a 3-month period between immediate and prolonged PET studies, compared with 3 months before VNS began., Conclusions: Seizure control improved during a period over which some immediate VNS-induced CBF changes declined (mainly over cortical regions), whereas other VNS-induced CBF changes persisted (mainly over subcortical regions). Altered synaptic activities at sites of persisting VNS-induced CBF changes may reflect antiseizure actions., (Copyright 2004 International League Against Epilepsy)

Objective: To investigate thoracic radiology usage over and above the secular trends associated with hospital-wide changes in the number of patients over a decade., Materials and Methods: We retrospectively reviewed administrative data from our 905-bed tertiary-care hospital between January 1, 1992, to December 31, 2001. Three points of entry to the radiology department were identified: inpatient (IP), outpatient (OP), and the emergency room (ER). The total numbers of patients, imaging studies, chest radiographs, chest CTs, CTs for pulmonary embolism, pulmonary angiograms, ventilation/perfusion scintigrams (V/Qs), lung biopsies, cardiac and chest MRIs, and FDG-PET scans for lung nodules and masses were collected. The significance of trends using linear regression analysis was evaluated., Results: IP and OP numbers have significantly increased over a decade (P = 0.04 and P = 0.01 respectively); ER patient numbers have not. There has been an increase in the ratio of chest radiographs per patient arising from the ER area (P = 0.0002). All 3 areas demonstrated an increase in the ratio of chest CTs per patient: IP (P = 0.0002), OP (P = <0.0001), and ER (P = <0.0001). IP and ER areas demonstrated an increase in the ratio of CTs for pulmonary embolism per patient (P = 0.006, P = 0.04 respectively). There was a decrease in the ratios of pulmonary angiograms and V/Qs per IP (P = 0.02 & P = 0.0003 respectively). Cardiac MRIs per patient demonstrated an increase (IP P = 0.01, OP P = 0.02). FDG-PET for lung nodules and masses per patient demonstrated an increase in IP (P = 0.03) and OP (P = 0.003) areas. The total number of chest imaging studies divided by the total number of imaging studies demonstrated an increase in IP and ER areas (P = 0.02 and P = 0.02 respectively)., Conclusion: There has been an increase in thoracic radiology usage above secular trends, particularly in the regions of chest CT and FDG-PET. CT is replacing more traditional techniques to diagnose pulmonary embolism for inpatients.

Objective: Several structural and functional brain imaging studies have pointed to a disturbance of thalamic subnuclei in patients with schizophrenia. The dopamine hypothesis of schizophrenia has, however, not been thoroughly examined in terms of this complex structure, which has connections with most brain regions of central interest in schizophrenia research. The aim of the present study was to examine dopamine D(2) receptor binding in subregions of the thalamus in patients with schizophrenia., Method: The authors used positron emission tomography and the radioligand [(11)C]FLB457 to examine dopamine D(2) receptor binding in thalamic subregions of 10 drug-naive patients with schizophrenia. Binding potential was calculated by the reference tissue method and used as an index for dopamine D(2) receptor binding. Comparisons were made with 19 healthy subjects. Subregions of interest were defined on individual magnetic resonance images using a percentage-based operational approach. Clinical symptoms were rated by using the Brief Psychiatric Rating Scale (BPRS)., Results: The [(11)C]FLB457 binding potential was lower in the central medial and posterior subregions of the thalamus in patients with schizophrenia. At a functional level, there was a significant negative correlation between binding potential and BPRS positive symptom scores., Conclusions: The subregions with low D(2) receptor binding comprise primarily the dorsomedial nucleus and pulvinar, two important components in circuitries previously suggested in the pathophysiology of schizophrenia. Aberrant dopaminergic neurotransmission in thalamic subregions might be a mechanism underlying positive symptoms in schizophrenia.

In recent years, mutual information has proved to be an excellent criterion for registration of intra-individual images from different modalities. Multi-resolution coarse-to-fine optimization was proposed for speeding-up of the registration process. The aim of our work was to further improve registration speed without compromising robustness or accuracy. We present and evaluate two procedures for co-registration of positron emission tomography (PET) and magnetic resonance (MR) images of human brain that combine a multi-resolution approach with an automatic segmentation of input image volumes into areas of interest and background. We show that an acceleration factor of 10 can be achieved for clinical data and that a suitable preprocessing can improve robustness of registration. Emphasis was laid on creation of an automatic registration system that could be used routinely in a clinical environment. For this purpose, an easy-to-use graphical user interface has been developed. It allows physicians with no special knowledge of the registration algorithm to perform a fast and reliable alignment of images. Registration progress is presented on the fly on a fusion of images and enables visual checking during a registration.

Objective: To assess the usefulness of dual-head camera imaging with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in the identification of malignant pancreatic lesions., Material and Methods: Fifteen (15) patients with pancreatic masses (7 females and 8 males, mean age 52 10 years) have been studied prospectively. After a 12-hour fasting patients received 120 MBq of FDG and were imaged in a dual-head camera equipped with coincidence detection. The final diagnosis was obtained by histology (biopsy or surgery in 13 patients) or follow-up (in 2 patients)., Results: Nine patients showed FDG uptake, all had pancreatic cancer proven on histological examination. Six patients had no tracer uptake: two had chronic pancreatitis, 1 had insulinoma, 1 had gastrinoma and two had pancreatic adenocarcinoma. Overall sensitivity was 69%, specificity was 100% and accuracy was 73%., Conclusion: Dual-head camera FDG images seem potentially useful in the characterization of the nature of pancreatic lesions. However, a negative study does not rule out malignancy in this patient population.