Pulmonary 18F-FDG uptake helps refine current risk stratification in idiopathic pulmonary fibrosis (IPF).

PURPOSE: There is a lack of prognostic biomarkers in idiopathic pulmonary fibrosis (IPF) patients. The objective of this study is to investigate the potential of 18F-FDG-PET/ CT to predict mortality in IPF. METHODS: A total of 113 IPF patients (93 males, 20 females, mean age ± SD: 70 ± 9 years) were prospectively recruited for 18F-FDG-PET/CT. The overall maximum pulmonary uptake of 18F-FDG (SUVmax), the minimum pulmonary uptake or background lung activity (SUVmin), and target-to-background (SUVmax/ SUVmin) ratio (TBR) were quantified using routine region-of-interest analysis. Kaplan-Meier analysis was used to identify associations of PET measurements with mortality. We also compared PET associations with IPF mortality with the established GAP (gender age and physiology) scoring system. Cox analysis assessed the independence of the significant PET measurement(s) from GAP score. We investigated synergisms between pulmonary 18F-FDG-PET measurements and GAP score for risk stratification in IPF patients. RESULTS: During a mean follow-up of 29 months, there were 54 deaths. The mean TBR ± SD was 5.6 ± 2.7. Mortality was associated with high pulmonary TBR (p = 0.009), low forced vital capacity (FVC; p = 0.001), low transfer factor (TLCO; p < 0.001), high GAP index (p = 0.003), and high GAP stage (p = 0.003). Stepwise forward-Wald-Cox analysis revealed that the pulmonary TBR was independent of GAP classification (p = 0.010). The median survival in IPF patients with a TBR < 4.9 was 71 months, whilst in those with TBR > 4.9 was 24 months. Combining PET data with GAP data ("PET modified GAP score") refined the ability to predict mortality. CONCLUSIONS: A high pulmonary TBR is independently associated with increased risk of mortality in IPF patients.

Areas of normal pulmonary parenchyma on HRCT exhibit increased FDG PET signal in IPF patients.

PURPOSE: Patients with idiopathic pulmonary fibrosis (IPF) show increased PET signal at sites of morphological abnormality on high-resolution computed tomography (HRCT). The purpose of this investigation was to investigate the PET signal at sites of normal-appearing lung on HRCT in IPF. METHODS: Consecutive IPF patients (22 men, 3 women) were prospectively recruited. The patients underwent (18)F-FDG PET/HRCT. The pulmonary imaging findings in the IPF patients were compared to the findings in a control population. Pulmonary uptake of (18)F-FDG (mean SUV) was quantified at sites of morphologically normal parenchyma on HRCT. SUVs were also corrected for tissue fraction (TF). The mean SUV in IPF patients was compared with that in 25 controls (patients with lymphoma in remission or suspected paraneoplastic syndrome with normal PET/CT appearances). RESULTS: The pulmonary SUV (mean ± SD) uncorrected for TF in the controls was 0.48 ± 0.14 and 0.78 ± 0.24 taken from normal lung regions in IPF patients (p < 0.001). The TF-corrected mean SUV in the controls was 2.24 ± 0.29 and 3.24 ± 0.84 in IPF patients (p < 0.001). CONCLUSION: IPF patients have increased pulmonary uptake of (18)F-FDG on PET in areas of lung with a normal morphological appearance on HRCT. This may have implications for determining disease mechanisms and treatment monitoring.

Automatic semi-quantification of [123I]FP-CIT SPECT scans in healthy volunteers using BasGan version 2: results from the ENC-DAT database.

PURPOSE: The aim of this study was to assess striatal dopamine transporter (DAT) availability in a large group of normal subjects. METHODS: The study included 122 healthy subjects, aged 18-83 years, recruited in the multicentre 'ENC-DAT' study (promoted by the European Association of Nuclear Medicine). Brain single photon emission computed tomography (SPECT) was acquired by means of dual-head cameras 3 h after [(123)I]FP-CIT administration. Specific to nondisplaceable binding ratios (SBRs) in the basal ganglia were computed using the 'BasGan' software, allowing automatic value extraction with partial volume effect correction. Multicentre camera inhomogeneity was taken into account by calibrating values on basal ganglia phantom data. SBR in each caudate nucleus (C) and putamen (P) were the dependent variables in a repeated measures general linear model analysis; age, gender, handedness and body mass index (BMI) were the independent variables. RESULTS: SBR values in C and P were significantly associated with age (mean rate decrease with age: 0.0306 per year, or 0.57 % of the general mean; p < 0.0001) and gender (women had higher values; p = 0.015), while no significant effect was found for handedness and BMI. A significant interaction was found between age and region (p < 0.0001) as the age-related decline was 0.028 for left C, 0.026 for right C and 0.034 for both P. P/C ratio analysis confirmed that age-related SBR decrease was stronger in P than in C (p < 0.0001). No significant effect was found for season or time of the day when the scan was acquired by analysing the residual of SBR values in C and P, after subtraction of age and gender effects. CONCLUSION: This study confirms the dependency of DAT on ageing and highlights the gender differences in a large sample of healthy subjects, while it does not support the dependency of DAT on BMI, handedness, circadian rhythm or season.

Integrated 18F-fluorodeoxyglucose-positron emission tomography/dynamic contrast-enhanced computed tomography to phenotype non-small cell lung carcinoma.

We applied modern molecular and functional imaging to the pretreatment assessment of lung cancer using combined dynamic contrast-enhanced computed tomography (DCE-CT) and (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) to phenotype tumors. Seventy-four lung cancer patients were prospectively recruited for (18)F-FDG-PET/DCE-CT using PET/64-detector CT. After technical failures, there were 64 patients (35 males, 29 females; mean age [± SD] 67.5 ± 7.9 years). DCE-CT yielded tumor peak enhancement (PE) and standardized perfusion value (SPV). The uptake of (18)F-FDG quantified on PET as the standardized uptake value (SUV(max)) assessed tumor metabolism. The median values for SUV(max) and SPV were used to define four vascular-metabolic phenotypes. There were associations (Spearman rank correlation [rs]) between tumor size and vascular-metabolic parameters: SUV(max) versus size (rs  =  .40, p  =  .001) and SUV/PE versus size (r  =  .43, p < .001). Patients with earlier-stage (I-IIA, n  =  30) disease had mean (± SD) SUV/PE 0.36 ± 0.28 versus 0.56 ± 0.32 in later-stage (stage IIB-IV, n  =  34) disease (p  =  .007). The low metabolism with high vascularity phenotype was significantly more common among adenocarcinomas (p  =  .018), whereas the high metabolism with high vascularity phenotype was more common among squamous cell carcinomas (p  =  .024). Other non-small cell lung carcinoma tumor types demonstrated a high prevalence of the high metabolism with low vascularity phenotype (p  =  .028). We show that tumor subtypes have different vascular-metabolic associations, which can be helpful clinically in managing lung cancer patients to hone targeted therapy.

Novel positron emission tomography/computed tomography of diffuse parenchymal lung disease combining a labeled somatostatin receptor analogue and 2-deoxy-2[18F]fluoro-D-glucose.

We prospectively investigated the potential of positron emission tomography (PET) using the somatostatin receptor (SSTR) analogue 68Ga-DOTATATE and 2-deoxy-2[¹8F]fluoro-D-glucose (¹8F-FDG) in diffuse parenchymal lung disease (DPLD). Twenty-six patients (mean age 68.9 ± 11.0 years) with DPLD were recruited for 68Ga-DOTATATE and ¹8F-FDG combined PET/high-resolution computed tomography (HRCT) studies. Ten patients had idiopathic pulmonary fibrosis (IPF), 12 patients had nonspecific interstitial pneumonia (NSIP), and 4 patients had other forms of DPLD. Using PET, the pulmonary tracer uptake (maximum standardized uptake value [SUV(max)]) was calculated. The distribution of PET tracer was compared to the distribution of lung parenchymal changes on HRCT. All patients demonstrated increased pulmonary PET signal with 68Ga-DOTATATE and ¹8F-FDG. The distribution of parenchymal uptake was similar, with both tracers corresponding to the distribution of HRCT changes. The mean SUV(max) was 2.2 ± 0.7 for 68Ga-DOTATATE and 2.8 ± 1.0 (t-test, p  =  .018) for ¹8F-FDG. The mean 68Ga-DOTATATE SUV(max) in IPF patients was 2.5 ± 0.9, whereas it was 2.0 ± 0.7 (p  =  .235) in NSIP patients. The correlation between 68Ga-DOTATATE SUV(max) and gas transfer (transfer factor of the lung for carbon monoxide [TLCO]) was r  =  -.34 (p  =  .127) and r  =  -.49 (p  =  .028) between ¹8F-FDG SUV(max) and TLCO. We provide noninvasive in vivo evidence in humans showing that SSTRs may be detected in the lungs of patients with DPLD in a similar distribution to sites of increased uptake of ¹8F-FDG on PET.

Defining the role of PET-CT in staging early breast cancer.

INTRODUCTION: Currently, there is a lack of data on the role of combined positron emission tomography-computed tomography (PET-CT) in the staging of early invasive primary breast cancer. We therefore evaluated the role of (18)F-fluorodeoxyglucose ((18)F-FDG)-PET-CT in this patient population. METHODS: We prospectively recruited 70 consecutive patients (69 women, one man; mean age, 61.9 ± 8.1 years) with early primary breast cancer for staging with (18)F-FDG-PET-CT. All PET-CT images were interpreted by two readers (independently of each other). A third reader adjudicated any discrepancies. All readers had ≥5 years of specific experience. Ethics board approval and informed consent were obtained. RESULTS: The mean clinical follow-up was 22.7 ± 12.6 months. The primary tumor was identified with PET-CT in 64 of 70 patients. Of the unidentified lesions, surgical pathology revealed two intraductal carcinomas, one invasive tubular carcinoma, and three invasive lobular carcinomas. Undiagnosed multifocal breast disease was shown in seven of 70 patients. PET-CT identified avid axillary lymph nodes in 19 of 70 patients, compared with 24 of 70 confirmed during surgery. There were four patients who were axillary node positive on PET but had no axillary disease at surgery. Five patients were reported with avid metastases. Two of those patients were treated for metastatic disease (nodal, lung, and liver in one and bone metastases in the other) following further imaging and clinical assessment. In the other three patients, lesions (lung, n = 1; pleural, n = 1; paratrachael node, n = 1) were subsequently diagnosed as benign lesions. CONCLUSION: Integrated (18)F-FDG-PET-CT may have a role in staging patients presenting with early breast cancer.

Prognostic role of PET scanning before and after reduced-intensity allogeneic stem cell transplantation for lymphoma.

Allogeneic stem cell transplantation (SCT) is an established therapy for patients with relapsed lymphoma, but the role of positron emission tomography (PET) scanning preallogeneic and postallogeneic SCT is uncertain. We investigated whether pretransplantation PET status predicted outcome after allogeneic SCT and whether PET surveillance after transplantation provided additional information compared with computed tomography (CT) scanning. Eighty consecutive patients with lymphoma who received a reduced-intensity allogeneic SCT were entered onto a prospective trial. PET and CT scans were performed before transplantation and up to 36 months after transplantation. Forty-two patients were PET-positive before transplantation. Pretransplantation PET status had no significant impact on either relapse rate or overall survival. Thirty-four relapses were observed, of which 17 were PET-positive with a normal CT scan at relapse. Donor lymphocyte infusion (DLI) was administered in 26 episodes of relapse and was guided by PET alone in 14 patients. These findings suggest that, in contrast to autologous SCT, pretransplantation PET status is not predictive of relapse and survival after allogeneic SCT for lymphoma. Posttransplantation surveillance by PET detected relapse before CT in half of episodes, often allowing earlier administration of DLI in patients with recurrent lymphoma, and permitted withholding of potentially harmful DLI in those with PET-negative masses on CT scans.

The role of 18FDG PET/CT in the management of colorectal liver metastases.

INTRODUCTION: Surgical resection remains the only potentially curative treatment for colorectal liver metastases (CLM). However, involvement of both the hepatic lobes or extrahepatic disease (EHD) can be a contra-indication for resection. The aim of the present study was to examine the addition of combined positron emission and computed tomography (PET/CT) to CLM staging to assess the effects upon staging and management. METHODS: All CLM patients referred to a single centre between January 2005 and January 2009 were prospectively included. All underwent routine staging (clinical examination and computed tomography), followed by a whole body (18) fluoro-deoxy-glucose ((18)FDG)-PET/CT scan and Fong clinical risk score calculation. RESULTS: Sixty-four patients were included [63% male with a median age of 63 years (age range 32-79 years)]. The addition of PET/CT led to disease upstaging in 20 patients (31%) and downstaging in two patients (3%). EHD was found in 24% of low-risk patients (Fong score 0-2) as compared with 44% of high-risk patients (Fong score 3-5) (P= 0.133). There was a trend towards a greater influence upon management in patients with a low score (44% vs. 17%; P= 0.080). CONCLUSION: The addition of PET/CT led to management changes in over one-third of patients but there was no correlation between alterations in staging or management and the Fong clinical risk score; suggesting that PET/CT should be utilized, where available, in the pre-operative staging of CLM patients.

Delivering affordable cancer care in high-income countries.

The burden of cancer is growing, and the disease is becoming a major economic expenditure for all developed countries. In 2008, the worldwide cost of cancer due to premature death and disability (not including direct medical costs) was estimated to be US$895 billion. This is not simply due to an increase in absolute numbers, but also the rate of increase of expenditure on cancer. What are the drivers and solutions to the so-called cancer-cost curve in developed countries? How are we going to afford to deliver high quality and equitable care? Here, expert opinion from health-care professionals, policy makers, and cancer survivors has been gathered to address the barriers and solutions to delivering affordable cancer care. Although many of the drivers and themes are specific to a particular field-eg, the huge development costs for cancer medicines-there is strong concordance running through each contribution. Several drivers of cost, such as over-use, rapid expansion, and shortening life cycles of cancer technologies (such as medicines and imaging modalities), and the lack of suitable clinical research and integrated health economic studies, have converged with more defensive medical practice, a less informed regulatory system, a lack of evidence-based sociopolitical debate, and a declining degree of fairness for all patients with cancer. Urgent solutions range from re-engineering of the macroeconomic basis of cancer costs (eg, value-based approaches to bend the cost curve and allow cost-saving technologies), greater education of policy makers, and an informed and transparent regulatory system. A radical shift in cancer policy is also required. Political toleration of unfairness in access to affordable cancer treatment is unacceptable. The cancer profession and industry should take responsibility and not accept a substandard evidence base and an ethos of very small benefit at whatever cost; rather, we need delivery of fair prices and real value from new technologies.

What is the relationship between ¹8F-FDG aortic aneurysm uptake on PET/CT and future growth rate?

PURPOSE: In this study we investigate the relationship between (18)F-fluorodeoxyglucose (FDG) metabolism and future aneurysm expansion measured by serial duplex ultrasound. Current screening programmes are increasing the identification of patients with abdominal aortic aneurysm (AAA). The management of these patients remains challenging and methods of risk stratification are sought. METHODS: Thirty-four consecutive patients [31 men, 3 women, median age 75 years, interquartile range (IQR) 71-78] with aortic aneurysms under routine surveillance with serial ultrasound were prospectively recruited for (18)F-FDG positron emission tomography (PET)/CT. A whole vessel type analysis was performed measuring the highest aortic wall (18)F-FDG uptake (standardized uptake value or SUV(max)), and target to background ratio (TBR) for each axial image and median SUV(max) and TBR value were calculated. Institutional Review Board permission and informed patient consent were obtained. RESULTS: Nine patients failed to undergo 12-month follow-up study (deceased n = 2, withdrew n = 1, failed to attend ultrasound scan n = 5, emergency aneurysm repair n = 1) leaving 25 patients for analysis. The median whole vessel SUV(max) was 1.70 (IQR 1.45-2.08). The median whole vessel TBR was 1.15 (IQR 1.00-1.40). The median aneurysm expansion at 12 months was 2.0 mm (IQR 0.5-5.0). The correlation (r) between (18)F-FDG SUV(max) and ultrasound expansion at 1 year was -0.501 (p = 0.011). CONCLUSION: The preliminary findings from this observational longitudinal pilot study suggest that there is an inverse trend between (18)F-FDG uptake on PET and future AAA expansion. Aortic aneurysms with lower metabolic activity may therefore be more likely to expand.

¹8F-FDG PET and biomarkers for tumour angiogenesis in early breast cancer.

PURPOSE: Tumour angiogenesis is an independent and strong prognostic factor in early breast carcinoma. We performed this study to investigate the ability of (18)F-FDG to detect angiogenesis in early breast carcinoma using PET/CT. METHODS: Twenty consecutive patients with early (T1-T2) breast carcinoma were recruited prospectively for 18F-FDG PET/CT. The PET/CT data were used to calculate whole tumour maximum standardized uptake value (SUV(max)) and mean standardized uptake value (SUV(mean)). All patients underwent subsequent surgery without prior chemotherapy or radiotherapy. The excised tumour underwent immunohistochemistry for vascular endothelial growth factor (VEGF), CD105 and glucose transporter protein 1 (GLUT1). RESULTS: The SUV(max) showed the following correlation with tumour histology: CD105: r = 0.60, p = 0.005; GLUT1: r = 0.21, p = 0.373; VEGF: r = -0.16, p = 0.496. The SUV(mean) showed the following correlation with tumour histology: CD105: r = 0.65, p = 0.002; GLUT1: r = 0.34, p = 0.144; VEGF: r = -0.18, p = 0.443 CONCLUSION: (18)F-FDG uptake is highly significantly associated with angiogenesis as measured by the immunohistochemistry with CD105 for new vessel formation. Given that tumour angiogenesis is an important prognostic indicator and a predictor of treatment response, (18)F-FDG PET may have a role in the management of primary breast cancer patients even in early-stage disease.

Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera.

PURPOSE: We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. METHODS: Of 27 consecutive patients recruited, 24 (64.5+/-11.8 years of age, 16 men) were injected with 74 MBq of (201)Tl (rest) and 250 MBq (99m)Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest (201)Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress (99m)Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest (201)Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). RESULTS: Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest (201)Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, p<0.0001 for all). In six patients stress perfusion defects were significantly larger on stress DR D-SPECT images, and five of these patients were imaged earlier by D-SPECT than by conventional SPECT. CONCLUSION: Fast and high-quality simultaneous DR MPI is feasible with D-SPECT in a single imaging session with comparable diagnostic performance and image quality to conventional SPECT and to a separate rest (201)Tl D-SPECT acquisition.

18F-FDG PET and PET/CT in the evaluation of cancer treatment response.

Multimodality imaging, as represented by its greatest exponent, PET/CT, has a firm place in the evaluation of a patient presenting with cancer. With 18F-FDG, PET/CT is rapidly becoming the key investigative tool for the staging and assessment of cancer recurrence. In the last 5 y, PET/CT has also gained widespread acceptance as a key tool used to demonstrate early response to intervention and therapy. In this setting, a major clinical need is being addressed with 18F-FDG PET/CT, because of its inherent ability to demonstrate (before other markers of response) if disease modification has occurred. This review presents available evidence to this effect.

Idiopathic pulmonary fibrosis and diffuse parenchymal lung disease: implications from initial experience with 18F-FDG PET/CT.

UNLABELLED: The purpose of this study was to evaluate integrated (18)F-FDG PET/CT in patients with idiopathic pulmonary fibrosis (IPF) and diffuse parenchymal lung disease (DPLD). METHODS: Thirty-six consecutive patients (31 men and 5 women; mean age +/- SD, 68.7 +/- 9.4 y) with IPF (n = 18) or other forms of DPLD (n = 18) were recruited for PET/CT and high-resolution CT (HRCT), acquired on the same instrument. The maximal pulmonary (18)F-FDG metabolism was measured as a standardized uptake value (SUV(max)). At this site, the predominant lung parenchyma HRCT pattern was defined for each patient: ground-glass or reticulation/honeycombing. Patients underwent a global health assessment and pulmonary function tests. RESULTS: Raised pulmonary (18)F-FDG metabolism in 36 of 36 patients was observed. The parenchymal pattern on HRCT at the site of maximal (18)F-FDG metabolism was predominantly ground-glass (7/36), reticulation/honeycombing (26/36), and mixed (3/36). The mean SUV(max) in patients with ground-glass and mixed patterns was 2.0 +/- 0.4, and in reticulation/honeycombing it was 3.0 +/- 1.0 (Mann-Whitney U test, P = 0.007). The mean SUV(max) in patients with IPF was 2.9 +/- 1.1, and in other DPLD it was 2.7 +/- 0.9 (Mann-Whitney U test, P = 0.862). The mean mediastinal lymph node SUV(max) (2.7 +/- 1.3) correlated with pulmonary SUV(max) (r = 0.63, P < 0.001). Pulmonary (18)F-FDG uptake correlated with the global health score (r = 0.50, P = 0.004), forced vital capacity (r = 0.41, P = 0.014), and transfer factor (r = 0.37, P = 0.042). CONCLUSION: Increased pulmonary (18)F-FDG metabolism in all patients with IPF and other forms of DPLD was observed. Pulmonary (18)F-FDG uptake predicts measurements of health and lung physiology in these patients. (18)F-FDG metabolism was higher when the site of maximal uptake corresponded to areas of reticulation/honeycomb on HRCT than to those with ground-glass patterns.

Vascular inflammation imaging with 18F-FDG PET/CT: when to image?

UNLABELLED: We prospectively investigated the ideal imaging time to measure vascular uptake after injection of (18)F-FDG. METHODS: A total of 17 patients with atherosclerotic abdominal aortic aneurysm underwent dynamic abdominal PET/CT using 2-min frames between 45 and 53, 57 and 65, 115 and 123, and 175 and 183 min after injection of (18)F-FDG. For each period of dynamic imaging, vessel wall and lumen uptake were measured using the maximum standardized uptake value (SUV(max)) and target-to-background ratio (TBR). RESULTS: No significant difference in TBR across all time points (repeated measures ANOVA, P = 0.206) was observed, despite a significant difference in aortic wall and lumen uptake with time (repeated measures ANOVA, P = 0.02 and P < 0.001, respectively). There was no significant difference between aortic wall uptake at 60 min (SUV(max), 2.15 +/- 0.11 SE) and 180 min (SUV(max), 1.99 +/- 0.18 SE) (paired t test, P = 0.367). There was a significant difference in lumen uptake at 60 min (SUV(max), 2.4 +/- 0.11 SE) and 180 min (SUV(max), 1.7 +/- 0.1 SE) (paired t test, P = 0.001). There was no significant difference in TBR between 60 min (0.91 +/- 0.03) and 180 min (1.01 +/- 0.06 SE) (paired t test, P = 0.131). With increasing delayed imaging, there was increasing variability (SE) in the SUV(max) for the aortic wall and TBRs. CONCLUSION: There was no significant advantage in imaging at 3 h over 1 h after (18)F-FDG injection.

Metabolic-flow relationships in primary breast cancer: feasibility of combined PET/dynamic contrast-enhanced CT.

PURPOSE: To assess the feasibility and first experience of combined (18)F-FDG-PET)/dynamic contrast-enhanced (DCE) CT in evaluating breast cancer. METHODS: Nine consecutive female patients (mean age 64.2 years, range 52-74 years) with primary breast carcinoma were prospectively recruited for combined (18)F-FDG PET/DCE-CT. Dynamic CT data were used to calculate a range of parameters of tumour vascularity, and tumour (18)F-FDG uptake (standardized uptake value, SUVmax) was used as a metabolic indicator. RESULTS: One tumour did not enhance and was excluded. The mean tumour SUVmax was 7.7 (range 2.4-26.1). The mean values for tumour perfusion, perfusion normalized to cardiac output, standard perfusion value (SPV) and permeability were 41 ml/min per 100 g (19-59 ml/min per 100 g), 0.56%/100 g (0.33-1.09%/100 g), 3.6 (2.5-5.9) and 0.15/min (0.09-0.30/min), respectively. Linear regression analysis showed a positive correlation between tumour SUV and tumour perfusion normalized to cardiac output (r=0.55, p=0.045) and a marginal correlation between tumour SUV and tumour SPV (r=0.19, p=0.065). There were no significant correlations between tumour SUV and tumour perfusion (r=0.29, p=0.401) or permeability (r=0.03, p=0.682). CONCLUSION: The first data from combined (18)F-FDG-PET/DCE-CT in breast cancer are reported. The technique was successful in eight of nine patients. Breast tumour metabolic and vascular parameters were consistent with previous data from (15)O-H(2)O-PET.

First experience of combined cardiac PET/64-detector CT angiography with invasive angiographic validation.

PURPOSE: Despite modern CT systems and expert evaluators, the diagnostic performance of coronary CT angiography is limited by overestimation of vessel stenosis which reduces the positive predictive value (PPV) of the test. The aim of this study was to evaluate the performance of combined cardiac PET/64-detector CT angiography. METHODS: Included in this retrospective study were 33 consecutive patients (5 women, 28 men; mean age 61.6 years, range 47-87 years, mean BMI 27.3+/-5.2 kg/m(2)) with clinically suspected flow-limiting coronary artery disease who underwent combined cardiac PET/64-detector CT angiography and invasive angiography. Combined PET/CT images were reported by an experienced dual-accredited radiologist/nuclear physician. An experienced cardiac CT radiologist re-read the CT images without PET. Stenotic disease was defined as >50% vessel narrowing. Invasive coronary angiography was used as a reference standard. Local ethics committee approval and patient consent were obtained. RESULTS: CT angiography (without PET data) was concordant with invasive angiography in 31/33 patients and at a patient level, the sensitivity in detecting significant coronary artery lesions was 100%, the specificity was 82%, the PPV was 92% and the negative predictive value (NPV) was 100%. Using combined PET/CT angiography the findings were concordant with invasive angiography in 32/33 patients and at a patient level, the sensitivity was 96%, the specificity was 100%, the PPV was 100% and the NPV was 91%. CONCLUSION: The use of integrated cardiac PET/64-detector CT angiography is feasible and appears to improve some aspects of the diagnostic performance of 64-detector coronary artery angiography in detecting coronary artery disease.

Functional imaging of neuroendocrine tumors with combined PET/CT using 68Ga-DOTATATE (DOTA-DPhe1,Tyr3-octreotate) and 18F-FDG.

BACKGROUND: The aim was to assess the relevant distribution of the novel PET tracer (68)Ga-DOTATATE in neuroendocrine tumors (NETs) with combined positron emission tomography / computed tomography (PET/CT) and compare its performance with that of (18)F-FDG PET/CT. METHODS: The imaging findings with (68)Ga-DOTATATE and (18)F-FDG on 38 consecutive patients with a diagnosis of primary or recurrent NET were compared and correlated with tumor grade on histology based on ki67 and mitotic index. RESULTS: The sensitivity of (68)Ga-DOTATATE PET/CT was 82% (31 of 38) and that of (18)F-FDG PET/CT was 66% (25 of 38). The sensitivity of combined (68)Ga-DOTATATE and (18)F-FDG PET/CT was 92% (35 of 38). There was greater uptake of (68)Ga-DOTATATE than (18)F-FDG in low-grade NET (median SUV 29 vs 2.9, P < .001). In high-grade NET there was higher uptake of (18)F-FDG over (68)Ga-DOTATATE (median SUV 11.7 vs 4.4, P = .03). There was a significant correlation with predominant tumor uptake of (68)Ga-DOTATATE or (18)F-FDG and tumor grade on histology (P < .0001). CONCLUSIONS: (68)Ga-DOTATATE PET/CT is a useful novel imaging modality for NETs and is superior to (18)F-FDG for imaging well-differentiated NET. Functional imaging with both (68)Ga-DOTATATE and (18)F-FDG has potential for a more comprehensive tumor assessment in intermediate- and high-grade tumors.