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Background: 99mTc-labelled bisphosphonates are used for imaging assessment of patients with transthyretin cardiac amyloidosis (ATTR). Present study evaluates whether quantitative SPECT/CT measurement of absolute myocardial 99mTc-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid (Tc-DPD) uptake can diagnose patients with suspected ATTR. Methods: Twenty-eight patients (25 male, age 80.03 ± 6.99 years) with suspected ATTR referred for Tc-DPD imaging had planar and SPECT/CT imaging of the chest. Three operators independently obtained Tc-DPD myocardial SUVmax and SUVmean above threshold (SMaT) (20, 40 and 60% of SUVmax), using a semi-automated threshold segmentation method. Results were compared to visual grading (0–3) of cardiac uptake. Results: Twenty-two patients (78%) had cardiac uptake (2 grade 1, 15 grade 2, 5 grade 3). SUVmax and SMaT segmentation thresholds enabled separating grades 2/3 from 0/1 with excellent inter- and intra-reader correlation. Cut-off values 6.0, 2.5, 3 and 4 for SUVmax, SMaT20,40,60, respectively, separated between grades 2/3 and 0 /1 with PPV and NPV of 100%. SMaT20,40,60(cardiac)/SUVmean (liver) and SMaT20,40,60(cardiac)/SUVmean(liver/lung) separated grades 2 and 3. Conclusion: Quantitative SPECT/CT parameters of cardiac Tc-DPD uptake are robust, enabling separation of patients with grades 2 and 3 cardiac uptake from grades 0 and 1. Larger patient cohorts will determine the incremental value of SPECT/CT quantification for ATTR management. [ABSTRACT FROM AUTHOR]

We audited whether 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (18FDG PET-CT) imaging could discriminate between different diagnoses in HIV-infected patients presenting with lymphadenopathy, with or without fever and/or splenomegaly. Maximum standardised uptake (SUVmax) values were similar in lymphoma and mycobacterial and fungal infections and were lower but similar in those with human herpesvirus (HHV) 8-associated disease and HIV-associated reactive lymphadenopathy. Nodal 18FDG avidity, with SUVmax ≥10, excluded diagnoses of HHV 8-associated disease and miscellaneous conditions, and HIV-associated reactive lymphadenopathy was additionally excluded in those who had undetectable plasma HIV viral loads. This audit suggests 18FDG PET-CT imaging did not permit discrimination between specific diagnoses but has utility in identifying lymph nodes with increased avidity that could be targeted for biopsy and in ruling out significant pathology. [ABSTRACT FROM AUTHOR]

Objective: To investigate the diagnostic performance of 18F-Fludeoxyglucose (18F-FDG) positron emission tomography (PET)/CT in patients with suspected large-vessel vasculitis and its potential to evaluate the extent and activity of disease. Methods: 78 consecutive patients (mean age 63 years; 53 females) with suspected large-vessel vasculitis were evaluated with 18F-FDG PET/CT. 18F-FDG uptake in the aorta and major branches was visually graded using a four-point scale and quantified with standardised uptake values (SUVmax). According to clinical diagnosis, patients were classified into three groups: (a) steroid-naïve, large-vessel vasculitis (16 patients), (b) vasculitis on steroid treatment (18 patients) and (c) no evidence of vasculitis (44 patients). Analysis of variance and linear regression were used to investigate the association of 18F-FDG uptake with clinical diagnosis and inflammatory markers. Results: 18F-FDG PET/CT was positive (visual uptake ≥2; equal to or greater than liver) in all patients with steroid-naïve, large-vessel vasculitis. The thoracic aorta, the carotid and the subclavian arteries were most frequently involved. In these patients, SUVmax values were significantly higher than in the other groups (analysis of variance; p<0.05). Linear regression showed a significant positive association (b-coefficients: 0.018-0.02; p<0.05) between SUVmax of the thoracic aorta and inflammatory markers in patients with vasculitis (Groups a and b). Patients on steroid treatment showed low visual scores (uptake ,2) and significantly lower SUVmax values than steroid-naïve patients. Conclusion: 18F-FDG PET/CT can detect the extent and activity of large-vessel vasculitis in untreated patients and is unreliable in diagnosing vasculitis in patients on steroids. [ABSTRACT FROM AUTHOR]

To compare the interobserver agreement and degree of confidence in anatomical localisation of lesions using 2-[fluorine-18]fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) and18F-FDG PET alone in patients with head and neck tumours. A prospective study of 24 patients (16 male, eight female, median age 59 years) with head and neck tumours was undertaken.18F-FDG PET/CT was performed for staging purposes. 2D images were acquired over the head and neck area using a GE Discovery LS™PET/CT scanner.18F-FDG PET images were interpreted by three independent observers. The observers were asked to localise abnormal18F-FDG activity to an anatomical territory and score the degree of confidence in localisation on a scale from 1 to 3 (1=exact region unknown; 2=probable; 3=definite). For all18F-FDG-avid lesions, standardised uptake values (SUVs) were also calculated. After 3 weeks, the same exercise was carried out using18F-FDG PET/CT images, where CT and fused volume data were made available to observers. The degree of interobserver agreement was measured in both instances. A total of six primary lesions with abnormal18F-FDG uptake (SUV range 7.2-22) were identified on18F-FDG PET alone and on18F-FDG PET/CT. In all, 15 nonprimary tumour sites were identified with18F-FDG PET only (SUV range 4.5-11.7), while 17 were identified on18F-FDG PET/CT. Using18F-FDG PET only, correct localisation was documented in three of six primary lesions, while18F-FDG PET/CT correctly identified all primary sites. In nonprimary tumour sites,18F-FDG PET/CT improved the degree of confidence in anatomical localisation by 51%. Interobserver agreement in assigning primary and nonprimary lesions to anatomical territories was moderate using18F-FDG PET alone (kappa coefficients of 0.45 and 0.54, respectively), but almost perfect with18F-FDG PET/CT (kappa coefficients of 0.90 and 0.93, respectively). We conclude that18F-FDG PET/CT significantly increases interobserver agreement and confidence in disease localisation of18F-FDG-avid lesions in patients with head and neck cancers.British Journal of Cancer (2005) 92, 1046-1050. doi:10.1038/sj.bjc.6602464 www.bjcancer.com Published online 15 March 2005 [ABSTRACT FROM AUTHOR]

Fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) provides valuable prognostic information in the management of lymphoma patients. However, the utility of18F-FDG PET following allografting is unclear. We analysed the use of18F-FDG PET after allogeneic reduced-intensity transplantation (RIT) performed in our institution. Between June 1998 and January 2002, 55 patients underwent RIT for either Hodgkin or non-Hodgkin lymphoma. At least one18F-FDG PET scan was performed during the post-transplant period (median five studies) in 15 (27·2%) of these 55 patients. PET scans were performed after re-staging computed tomography (CT) and were categorised depending on18F-FDG uptake. The first PET scan was informative in 11 of 15 patients (73%) and influenced the administration of donor lymphocyte infusions (DLI) in nine: leading to earlier DLI administration in two patients, earlier dose escalation in one, withholding of DLI administration in five and dose reduction in one. In addition, subsequent monitoring with18F-FDG PET scans documented a graft-versus-lymphoma effect in five patients (median post-DLI follow-up 33 months, range 13–36 months). These preliminary data suggest that18F-FDG PET has a role in guiding DLI administration and monitoring the immunotherapeutic effect in patients after allogeneic transplantation. This retrospective pilot study forms the basis for a prospective study to clarify the utility of18F-FDG PET/CT in these patients. [ABSTRACT FROM AUTHOR]