Sensitivity Of Positron Emission Tomography Research Articles

Positron Emission Tomography (PET) has Limited Utility in the Staging of Pancreatic Adenocarcinoma

BackgroundPositron emission tomography (PET) as an adjunct to conventional imaging in the staging of pancreatic adenocarcinoma is controversial. Herein, we assess the utility of PET in identifying metastatic disease and evaluate the prognostic potential of standard uptake value (SUV). MethodsImaging and follow-up data for patients diagnosed with pancreatic adenocarcinoma were reviewed retrospectively. Resectability was assessed based on established criteria, and sensitivity, specificity, and accuracy of PET were compared to those of conventional imaging modalities. ResultsFor 123 patients evaluated 2005–2011, PET and CT/MRI were concordant in 108 (88 %) cases; however, PET identified occult metastatic lesions in seven (5.6 %). False-positive PETs delayed surgery for three (8.3 %) patients. In a cohort free of metastatic disease in 78.9 % of cases, the sensitivity and specificity of PET for metastases were 89.3 and 85.1 %, respectively, compared with 62.5 and 93.5 % for CT and 61.5 and 100.0 % for MRI. Positive predictive value and negative predictive value of PET were 64.1 and 96.4 %, respectively, compared with 75.0 and 88.9 % for CT and 100.0 and 91.9 % for MRI. Average difference in maximum SUV of resectable and unresectable lesions was not statistically significant (5.65 vs. 6.5, p = 0.224) nor was maximum SUV a statistically significant predictor of survival (p = 0.18). ConclusionPET is more sensitive in identifying metastatic lesions than CT or MRI; however, it has a lower specificity, lower positive predictive value, and in some cases, can delay definitive surgical management. Therefore, PET has limited utility as an adjunctive modality in staging of pancreatic adenocarcinoma.

135 Novel Hybrid Positron Emission Tomography - Magnetic Resonance (PET-MR) Multi-modality Inflammatory Imaging has Improved Diagnostic Accuracy for Detecting Cardiac Sarcoidosis

BackgroundCardiac sarcoidosis (CS) is associated with poor outcomes, but detection remains difficult.Few studies evaluate 18-fluorodeoxyglucose positron emission tomography (PET) and cardiac magnetic resonance imaging (MRI) for CS diagnosis. None examine...

Diagnostic role of Gallium-68 DOTATOC and Gallium-68 DOTATATE PET in patients with neuroendocrine tumors: a meta-analysis

Gallium-68 somatostatin receptor positron emission tomography (PET) has been used in the diagnosis of neuroendocrine tumors (NETs). The compounds often used in molecular imaging of NETs with PET are 68Ga-DOTATOC, 68Ga-DOTATATE, and 68Ga-DOTANOC. There is varying affinity to different somatostatin receptors. To systematically review and perform a meta-analysis of published data regarding the diagnostic role of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs. A comprehensive literature search of studies published through 30 April 2013 regarding 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs was performed using the PubMed/MEDLINE, Embase, and Scopus databases. Pooled sensitivity and specificity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs. Ten studies comprising 416 patients with NETs were included in this meta-analysis. The pooled sensitivity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs calculated on a per-patient-based analysis was 93% (95% confidence interval [CI] 89-96%) and 96% (95% CI 91-99%). The pooled specificity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in diagnosing NETs was 85% (95% CI 74-93%) and 100% (95% CI 82-100%). The area under the ROC curve of 68Ga-DOTATOC and 68Ga-DOTATATE PET was 0.96 and 0.98, respectively, on a per-patient-based analysis. The molecular imaging agents 68Ga-DOTATOC and 68Ga-DOTATATE demonstrated high sensitivity and specificity in the diagnosis of NETs on PET scan. Although both are accurate tools in the diagnosis of NETs, 68Ga-DOTATATE PET may be more sensitive and specific than 68Ga-DOTATOC PET scan.

Diagnostic efficacy of PET and PET/CT for recurrent lung cancer: a meta-analysis

Lung cancer is one of the most common malignant tumors in the world, and is the leading cause of cancer-related mortality. Although there are no conclusive data to support the survival benefits of early detection or early treatment for recurrence, an early and accurate diagnosis of recurrence is critical to optimize therapy. To compare the diagnostic value of positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) using fluorine-18 deoxyglucose (18FDG) with conventional imaging techniques (CITs) for the detection of lung cancer recurrence. A meta-analysis was performed, with systematic searches conducted using PubMed and EMBASE databases (up to 31 December 2011). Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) values were calculated for 1035 patients reported in 13 articles. Summary receiver-operating characteristic curves (SROC) were also generated. The pooled sensitivity (95% CI) for PET, PET/CT, and CITs were 0.94 (0.91-0.97), 0.90 (0.84-0.95), and 0.78 (0.71-0.84), respectively. The pooled specificity (95% CI) for PET, PET/CT, and CITs were 0.84 (0.77-0.89), 0.90 (0.87-0.93), and 0.80 (0.75-0.84), respectively. Regarding sensitivity, lower values were associated with CITs than PET (P = 0.000) and PET/CT (P = 0.005), and there was no significant difference between PET/CT and PET (P = 0.102). Regarding specificity, values for PET/CT and PET were significantly higher than for CITs (both P = 0.000), and there was no significant difference between PET/CT and PET (P = 0.273). In the SROC curves, a better diagnostic accuracy was associated with PET/CT than PET and CITs. PET/CT and PET were found to be superior modalities for the detection of recurrent lung cancer, and PET/CT was superior to PET.

Positron emission tomography for measurement of copper fluxes in live organisms

Copper is an essential nutrient for the physiology of live organisms, but excessive copper can be harmful. Copper radioisotopes are used for measurement of copper fluxes in live organisms using a radioactivity assay of body fluids or whole-body positron emission tomography (PET). Hybrid positron emission tomography-computed tomography (PET/CT) is a versatile tool for real-time measurement of copper fluxes combining the high sensitivity and quantification capability of PET and the superior spatial resolution of CT for anatomic localization of radioactive tracer activity. Kinetic analysis of copper metabolism in the liver and extrahepatic tissues of Atp7b(-/-) knockout mice, a mouse model of Wilson's disease, demonstrated the feasibility of measuring copper fluxes in live organisms with PET/CT using copper-64 chloride ((64) CuCl2 ) as a radioactive tracer ((64) CuCl2 -PET/CT). (64) CuCl2 -PET/CT holds potential as a useful tool for the diagnosis of inherited and acquired human copper metabolism disorders and for monitoring the effects of copper-modulating therapy.

Diagnostic accuracy of 18F-FDG PET/CT for detection of advanced colorectal adenoma

To determine the accuracy of 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) in the detection of advanced colorectal adenomas. In this retrospective study, patient consent was waived by the institutional review board. Combined FDG whole-body PET and computed tomography (CT) images (2000-2009) were re-read and compared with reports of complete colonoscopy performed up to 1 year after the PET examination. One or more areas of focal colonic uptake greater than the background indicated a positive PET result, irrespective of standardized uptake value (SUV). Lesion and patient-level measures of PET accuracy with their 95% confidence intervals (CI) were calculated. One hundred and eighty patients undergoing colonoscopy with or without biopsy underwent PET within 1 year prior to colonoscopy. There were 92 women and 88 men (mean age 63.3 years). Indications for PET were extent of disease and treatment response in all cases. Patients had non-colorectal cancer (n = 160) or colon cancer (n = 20). One hundred and fourteen FDG-avid lesions were present. In 33, there was no colonoscopic correlate. Two hundred and fifty-eight biopsies revealed tubular adenomas (n = 91, one with intra-mucosal cancer), tubulovillous adenomas (n = 28), adenocarcinoma (n = 37), inflammation (n = 22), hyperplastic polyps (n = 54), serrated adenoma (n = 5), metastatic disease (n = 5), normal/benign mucosa or submucosal benign tumors (n = 13) or miscellaneous (n = 3). Per-lesion performance of PET showed a sensitivity of 38% (95% CI: 31-46; 64/167) for all adenomas and carcinomas and 58% (95% CI: 49-67; 57/98) for lesions ≥ 10 mm. At the patient level, for all adenomas and carcinomas the sensitivity was 54% (95% CI: 44-63; 61/113), specificity 100% (pre-defined), positive predictive value (PPV) 100% (pre-defined), and negative predictive value (NPV) 56% (95% CI: 47-65; 67/119). For patients with advanced adenoma, PET sensitivity was 49% (95% CI: 35-63; 26/53) specificity, 100%, PPV 100% and NPV 82% (95% CI: 76-88; 127/154). Five of 37 adenocarcinomas were not detected, one of which was mucinous at histology. FDG PET detected most cancers, but only identified one-half of patients harbouring advanced adenomas. Based on the data, PET cannot be relied upon to accurately identify patients with advanced adenoma.

Clinical experience with (18)F-fluorodeoxyglucose positron emission tomography and (123)I-metaiodobenzylguanine scintigraphy in pediatric neuroblastoma: complementary roles in follow-up of patients.

PurposeTo evaluate the potential utility of 123I-metaiodobenzylguanine (123I-MIBG) scintigraphy and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) for the detection of primary and metastatic lesions in pediatric neuroblastoma (NBL) patients, and to determine whether 18F-FDG PET is as beneficial as 123I-MIBG imaging.MethodsWe selected 8 NBL patients with significant residual mass after operation and who had paired 123I-MIBG and 18F-FDG PET images that were obtained during the follow-up. We retrospectively reviewed the clinical charts and the findings of 45 paired scans.ResultsBoth scans correlated relatively well with the disease status as determined by standard imaging modalities during follow-up; the overall concordance rates were 32/45 (71.1%) for primary tumor sites and 33/45 (73.3%) for bone-bone marrow (BM) metastatic sites. In detecting primary tumor sites, 123I-MIBG might be superior to 18F-FDG PET. The sensitivity of 123I-MIBG and 18F-FDG PET were 96.7% and 70.9%, respectively, and their specificity were 85.7% and 92.8%, respectively. 18F-FDG PET failed to detect 9 true NBL lesions in 45 follow-up scans (false negative rate, 29%) with positive 123I-MIBG. For bone-BM metastatic sites, the sensitivity of 123I-MIBG and 18F-FDG PET were 72.7% and 81.8%, respectively, and the specificity were 79.1% and 100%, respectively. 123I-MIBG scan showed higher false positivity (20.8%) than 18F-FDG PET (0%).Conclusion123I-MIBG is superior for delineating primary tumor sites, and 18F-FDG PET could aid in discriminating inconclusive findings on bony metastatic NBL. Both scans can be complementarily used to clearly determine discrepancies or inconclusive findings on primary or bone-BM metastatic NBL during follow-up.

Sub-millimeter nuclear medical imaging with high sensitivity in positron emission tomography using β+γ coincidences

We present a nuclear medical imaging technique,employing triple-γ trajectory intersections from β+−γ coincidences,able to reach sub-millimeter spatialresolution in 3 dimensions with a reduced requirement of reconstructed intersectionsper voxel compared to a conventional PET reconstruction analysis.This 'γ-PET' technique draws on specific β+-decaying isotopes,simultaneously emitting an additional photon. Exploitingthe triple coincidencebetween the positron annihilation and the third photon, it is possible to separate thereconstructed 'true' events from background. In order to characterize thistechnique, Monte-Carlo simulations and image reconstructions have been performed. Theachievable spatial resolution has been found to reach ca. 0.4 mm (FWHM) in each directionfor the visualization of a 22Na point source.Only 40 intersections are sufficient for a reliable sub-millimeter imagereconstruction of a point source embedded in a scattering volume of waterinside a voxel volume of about 1 mm3 ('high-resolution mode').Moreover, starting with an injected activity of 400 MBq for 76Br,the same number of only about 40 reconstructed intersections are needed in case ofa larger voxel volume of 2 x 2 x 3 mm3 ('high-sensitivity mode').Requiring such a low number of reconstructed events significantly reduces therequired acquisition time for image reconstruction (in the above case to about 140 s)and thus may open up the perspective for a quasi real-time imaging.

Clinical utility and limitations of FDG PET in detecting recurrent hepatocellular carcinoma in postoperative patients

The clinical usefulness of positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) for the detection of recurrent hepatocellular carcinoma (HCC) is controversial because HCC displays varying FDG avidity. The purposes of this study were to re-evaluate the utility of FDG PET for the detection of recurrent HCC, and to assess its prognostic value in a large series of postoperative patients. We retrospectively reviewed 113 scans in 86 patients undergoing FDG PET after curative surgery for HCC. These scans were performed for suspected recurrence on radiologic imaging (group A: n = 44) because of an elevated tumor marker level with negative prior imaging results (group B: n = 32) or with no suspicion of recurrence (group C: n = 37). FDG PET's accuracy for recurrence detection and its value as a predictor of survival were assessed. The sensitivity, specificity, and diagnostic accuracy were 53, 100, and 55 % for group A; 34, 100, and 41 % for group B; and 11, 100, and 78 % for group C, respectively. A change in therapy resulted from the scan results in 7, 9, and 8 % in groups A, B, and C, respectively. The combined sensitivities for intra- and extrahepatic recurrence were 30 and 42 %, respectively. Histopathological features at initial surgery did not affect the sensitivity. The overall survival of patients with positive scans was significantly poorer than that of patients with negative scans (P = 0.008). The sensitivity of FDG PET for recurrent HCC was low, with little change in treatment resulting. However, it can predict prognosis in postoperative patients.

Heavy PETting: Reducing Radiation Exposure From Intradepartment Positron Emission Tomography Scans

Increasingly, positron emission tomography (PET) scans are being utilized in radiation medicine departments for staging, treatment planning, and follow-up. Positron emission tomography scans use signals emitted from the radioactive tracer [F]-fluoro-2-deoxy-Dglucose (FDG-glucose) that is preferentially taken up by cancer cells. After image processing including fusion with simultaneously obtained computed tomography (CT) scans, the oncologist is able to identify tumors as they “light up.” Positron emission tomography scans are becoming a part of standard oncologic evaluation for many cancers for which their sensitivity and specificity for cancer detection is superior to CT scans. Positron emission tomography is used frequently at the time of simulation because treatment planning can be tailored by targeting areas of metabolically active tumor. Given the sensitivity of PET in cancer detection, it is being used increasingly as part of standard followup to evaluate response to treatment, to detect early recurrent or persistent disease, and to help differentiate radiation necrosis from tumor. With all these useful applications in our cancer patients, the number of PET scans ordered has risen significantly in the last few years. For example, taking just the US Veterans Administration patients treated in our department, the number of PET scans ordered increased from 100 scans in 2008 to 811 in 2012. This presents a new and unique problem in radiation protection. The FDG-glucose is administered intravenously at a typical dose of 5-10 mCi directly before scanning, and it remains in a patient’s circulation for several hours after administration, with a physical half-life of 110 minutes. The biologic half-life is dependent on urinary excretion. Given patient anxiety in cancer detection and the fact that PET scanners are often located in close proximity to the ordering radiation oncologist, physician visits are

Determination of optimum periods between onset of suspected acute myocarditis and 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of inflammatory left ventricular myocardium

PurposeTo determine optimum periods for 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) examination in subjects with suspected acute myocarditis, we compared 18F-FDG PET with endomyocardial biopsy (EMB) using the latest definition of 18F-FDG PET for inflammatory left ventricular (LV) myocardium. Materials and methodsRetrospective analysis of 29 subjects (18 male, 48±18years) who have symptoms or LV dysfunction underwent both 18F-FDG PET (Advance NXi, GE-Healthcare) under fasting conditions and EMB from LV posterior wall within 3months. ResultsWhen we defined 18F-FDG PET positive inflammatory LV posterior wall as ‘focal on diffuse’ pattern, sensitivity, specificity, and positive predictive values (PPV), and negative predictive values (NPV) of 18F-FDG PET for detecting active inflammatory LV posterior wall compared with EMB were 46.2, 81.3, 66.7, and 65.0%, respectively. Receiver operating characteristic curve of periods (days) between onset of clinically suspected acute myocarditis and performance of 18F-FDG PET for detecting inflammatory LV posterior wall demonstrated 17days as a best cut off values with area under the curve (0.497, P=0.982) with sensitivity=21.1% and specificity=100%. Sensitivity, specificity, PPV and NPV of 18F-FDG PET for detecting inflammatory LV posterior wall on EMB were all 100% when 18F-FDG PET was performed at 1–14days after onset of suspected acute myocarditis. ConclusionsIn our definition, 18F-FDG PET showed excellent agreement with EMB for detecting active inflammatory LV posterior wall in subjects with clinically suspected active acute myocarditis. If possible, 18F-FDG PET should be performed within 14days after the onset to maintain high diagnostic accuracy compared with EMB.

Axially Oriented Crystal Geometry Applied to Small-Animal PET System: A Proof of Concept

Improving resolution without decreasing sensitivity in positron emission tomography (PET) is of great interest for small animal studies. Traditional PET scanners use radially oriented detector block structures. This geometry implies a relationship between the spatial resolution and the sensitivity. An axially oriented crystal geometry can limit this correlation. With a fine measurement of the depth of interaction (DOI) and a continuous measurement of the axial interaction position, this axial geometry can provide high resolution and remove parallax effects. With a careful choice of the crystal and providing enough crystal elements in the radial direction, a good sensitivity can be achieved. Such improvements also allow a more accurate gamma tracking and Compton analysis of the events, indirectly increasing the sensitivity. We have proposed a PET scanner in which LYSO crystals are axially oriented and coupled at both ends by multichannel photo-detectors. The gamma interaction position is given by the hit crystals for the transverse plane and by the light spread on both photo-detectors for the axial direction. The axial position of the events is reconstructed using a calibration procedure and the transverse position is reconstructed using a clustering algorithm. In this paper, we present a complete simulation work flow, including the physical effects, the optical and electronic effects, as well as a reconstruction algorithm. A point sources phantom was used to evaluate the spatial resolutions, and a MOBY phantom was used for overall image quality evaluation. This paper shows that using four modules arranged around the animal, a volumetric spatial resolution below 1 mm3 can be achieved while keeping a detection efficiency close to 10%.

State of the Art in Cardiac Hybrid Technology: PET/MR

Simultaneous PET/MRI is an emerging technique combining two powerful imaging modalities in a single device. The wide variety of available tracers for perfusion and metabolic studies and the high sensitivity of positron emission tomography (PET) combined with the high spatial resolution and soft tissue contrast of magnetic resonance imaging (MRI) in depicting cardiac morphology and function as well as MRI's absence of ionizing radiation makes PET/MRI very attractive to radiologists and clinicians. Nevertheless, PET/MR scientific and clinical promise is to be considered in the context of numerous technical challenges that hinder its use in the clinical setting. For example, in order for a PET system to work correctly within an MR field, major changes are required to the photon detection chain such as the elimination of photomultiplier tubes, etc. Another significant limitation of PET/MRI is the lack of an electron density map (as is the case with PET-CT) that can be readily obtained from MRI (the latter measures proton not electron density) and used to correct PET data for attenuation. Moreover, as with PET-CT, cardiac and respiratory motions cause image degradations that affect image quality and accuracy both in static and dynamic PET imaging. As a result, overcoming these (and other) technical limitations is a very active area of research both in academic institutions as well as industry. In this paper, we review recent literature on cardiac PET/MRI, present the state-of-the-art of this technology, and explore promising preclinical and clinical cardiac applications where PET/MRI could play a substantial role.

Minimization of Parallax Error in Dedicated Breast PET

The increase of the detector thickness and the incidence angle of impinging photons permits an enhancement of sensitivity in positron emission tomography (PET) scanners. But also increases the parallax error and leads to a worsening of spatial resolution. Instead of introducing hardware modifications in the readout electronics or in the detector, we propose in this work to model the photon penetration depth in the detector material and to account for this effect during the image reconstruction. The validation of the model was based on experimental measurements with the MAMMI breast dedicated PET. It consists of twelve detector modules of monolithic LYSO scintillators. A point-like source was acquired at several radial positions across the field of view. The performance of the model was analyzed in terms of position accuracy and spatial resolution. Full width at half maximum (FWHM) average improvement values of 1.0 mm (radial), 0.4 mm (tangential), and 0.3 mm (axial) have been measured when the photon penetration depth was taken into account. The use of the model proposed in this work allows us to design PET detectors with improved sensitivity while maintaining the spatial resolution of the scanner.

A 3D-QSAR model for cannabinoid receptor (CB2) ligands derived from aligned pharmacophors

Cannabinoid (CB) receptors have gained much attention as markers for various brain tumours and potential therapeutic targets of neuropathic pain and mood disorders. Two CB receptors have been cloned and described: CB1, predominantly expressed in the brain and CB2, primarily found in the peripheral system but also in brain. The CB2 receptor is suggested to be involved in various neurodegenerative diseases, such as Alzheimer's or Parkinson's disease [1]. Early and non-invasive diagnosis and therapy monitoring of such diseases is desired. Positron-Emission-Tomography (PET) allows imaging of functional processes in living humans. For this, compounds with positron emitting labels like 18F are used. Due to the high sensitivity of PET, such radiotracers must bind to the target protein with high selectivity. Here, we utilise AutoGPA [2] implemented in the modelling suite MOE (Chemical Computing Group Inc., Montreal) to compute grid potentials build upon a 3D-QSAR model derived from a library of CB2 selective N-Aryl-oxadiazolyl-propionamides. Since a proper alignment of the molecules prior the analysis is crucial to the successful application of these models in further studies, the molecules were aligned based on their pharmacophore features. The obtained model delivers also knowledge of the 3D-structure of the binding site, which, in turn, can be used to refine 3D-models of the CB2 receptor. The steric and electrostatic contour maps are applied for identification of regions suitable for labelling with 18F, the most preferred PET radionuclide. Figure 1

Comments on the utility of endorbonchial ultrasound-guided transbronchial needle aspiration in mediastinal or hilar lymph node evaluation in extrathoracic malignancy: Benign or malignant?

Sir, I read with interest the article “The utility of EBUS-guided TBNA in mediastinal or hilar lymph node evaluation in extra thoracic malignancy: Benign or malignant.”[1] The primary end point of study in reference[1] was to determine the etiology and prevalence of malignancy for hypermetabolic and enlarged hilar/mediastinal lymph nodes in patients with previously diagnosed extra pulmonary malignancy. The article is very well written. The study is relevant in today's era of semi-invasive procedures with utmost importance given to safety and patient care. I would like to highlight one or two points related to the study in discussion. First, authors had suggested that sensitivity and specificity of endorbonchial ultrasound (EUS)-guided transbronchial needle aspiration (TBNA) is lower than that of EBUS, considering the number of lymph node (LN) which are accessible via EBUS.[1] But as per the literature, EUS is a more safe procedure and does not require mechanical ventilation.[2] Endorbonchial ultrasound-guided fine needle aspiration (EUS-FNA) has been shown to be particularly useful in the analysis of lesions in the aortopulmonary window (station 5), the subcarinal area (station 7) the lower paraoesophageal LN (station 8), and those in the ligamentum pulmonale (station 9).[2] Due to unavailability of EBUS in our hospital, we refer our patients for EUS which is done by Gastroenterologist. In our experience, we found that if performed for selected LN stations[2] the yield of EUS is similar to EBUS with lesser procedure-related risk (93% sensitivity and 100% specificity * unpublished data). The sensitivity of positron emission tomography (PET) scanning in staging the mediastinum is reported to vary from 0.5 to 1.0 in previous studies.[3] The cut-off values of SUV max of mediastinal lymph node recommended by various studies ranges from 2.5 to 5.3.[4] With this background, I would like to know whether authors observe any particular cut-off value of SUV max over positron emission tomography–computed tomography (PET-CT) among the 18 patients with proven malignancy. I understand that it was not one of the objectives of present study to determine cut-off value of SUV max over PET CT, but if authors would share this information, it will be very helpful to us, as in our hospital unlike EBUS, PET-CT is available. I once again would like to congratulate Parmakisz E T and colleagues for their work.

Phase II Safety and Clinical Comparison With Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging for Detection of Coronary Artery Disease

This was a phase II trial to assess flurpiridaz F 18 for safety and compare its diagnostic performance for positron emission tomography (PET) myocardial perfusion imaging (MPI) with Tc-99m single-photon emission computed tomography (SPECT) MPI with regard to image quality, interpretative certainty, defect magnitude, and detection of coronary artery disease (CAD) (≥50% stenosis) on invasive coronary angiography (ICA).In pre-clinical and phase I studies, flurpiridaz F 18 has shown characteristics of an essentially ideal MPI tracer.One hundred forty-three patients from 21 centers underwent rest-stress PET and Tc-99m SPECT MPI. Eighty-six patients underwent ICA, and 39 had low-likelihood of CAD. Images were scored by 3 independent, blinded readers.A higher percentage of images were rated as excellent/good on PET versus SPECT on stress (99.2% vs. 88.5%, p < 0.01) and rest (96.9% vs. 66.4, p < 0.01) images. Diagnostic certainty of interpretation (percentage of cases with definitely abnormal/normal interpretation) was higher for PET versus SPECT (90.8% vs. 70.9%, p < 0.01). In 86 patients who underwent ICA, sensitivity of PET was higher than SPECT (78.8% vs. 61.5%, respectively, p = 0.02). Specificity was not significantly different (PET: 76.5% vs. SPECT: 73.5%). Receiver-operating characteristic curve area was 0.82 ± 0.05 for PET and 0.70 ± 0.06 for SPECT (p = 0.04). Normalcy rate was 89.7% with PET and 97.4% with SPECT (p = NS). In patients with CAD on ICA, the magnitude of reversible defects was greater with PET than SPECT (p = 0.008). Extensive safety assessment revealed that flurpiridaz F 18 was safe in this cohort.In this phase 2 trial, PET MPI with flurpiridaz F 18 was safe and superior to SPECT MPI for image quality, interpretative certainty, and overall CAD diagnosis.

Application of FDG-PET/CT in Radiation Oncology

Positron emission tomography (PET)/computed tomography (CT), which combines the advantages of high sensitivity and specificity of PET and high resolution of CT, is a unique tool for cancer management. PET/CT has been widely used in cancer diagnosis and treatment. The article reviews the recent applications of PET/CT in radiation oncology, with a focus on 18F-fluorodeoxyglucose (FDG)-PET/CT, addressing the applications in treatment planning and treatment response assessment of radiation therapy.

11C-Choline PET-CT Detection of Osseous Metastases versus Bone Scan in Newly Diagnosed High Risk Prostate Cancer Patients-A Pilot Study

Purpose: Identification of osseous metastatic prostate adenocarcinoma (PCa) is traditionally based on bone scan and computerized tomography (CT) imaging. Positron emission tomography (PET) has been investigated to improve detection of metastatic disease. Given the high number of false positive and false negative results with 18-fluorodeoxyglucose (18F-FDG) PET, novel tracers including 11C-Choline have been investigated for earlier identification metastatic disease. We present a prospective pilot study comparing 11C-Choline PET/CT against traditional bone scan in detecting osseous metastases in newly diagnosed high risk PCa. Methods: High-risk PCa patients underwent a standard initial workup: H&P, transrectal US-guided biopsy, PSA evaluation, CT scan, and bone scan. An experimental 11C-Choline PET/CT scan served to evaluate the extent of disease and predict for occult metastases. Pre-treatment bone scan and 11C-Choline PET/CT interpretations were compared with follow-up imaging, PSA, and clinical assessments to determine the predictive value of pre-treatment 11C-Choline imaging and overall outcomes. Results: Nine patients were successfully enrolled with 11C-Choline PET imaging during the initial workup. Three patients had evidence of osseous metastases on both CT and bone scans. Two of three patients had clinical findings consistent with their imaging, with all three patients exhibiting baseline PSA levels >50. Of the three patients deemed metastatic by conventional radiography, only two of the three corresponding 11C-Choline PET/CT images were in agreement with conventional imaging. The final patient had a negative 11C-Choline study with a T10 sclerotic focus on conventional imaging that was unchanged in follow-up scans despite post-treatment biochemical failure. A fourth patient without evidence of osseous metastatic disease on conventional scans demonstrated a positive 11C-Choline PET/CT scan on initial workup. In follow-up, the patient had evidence of diffuse osseous metastatic disease visualized on conventional imaging. Conclusion: In this limited prospective series, our results suggest an increased sensitivity of 11C-Choline PET/ CT in identifying active lytic lesions and true bony metastasis.

FDG-PET in diagnosis, staging and prognosis of pancreatic carcinoma: A meta-analysis

To investigate the potential role of positron emission tomography (PET) in the diagnosis, staging and prognosis predicting of pancreatic carcinoma (PC). A systematic review of relevant literatures in PubMed, Embase and Cochrane Library was performed. The sensitivity and specificity of diagnostic and staging studies, and HRs for prognosis predicting studies were pooled. The bivariate model was used for diagnostic studies and the random-effect model for prognostic studies. Heterogeneity between included studies was tested using χ(2) test, and subgroup analysis was performed to explain the heterogeneities. All of the calculations were performed using Stata version 11.0. A total of 39 studies were included. The pooled sensitivity of PET in diagnosing PC (30 studies, 1582 patients), evaluating N stating (4 studies, 101 patients) and liver metastasis (7 studies, 316 patients) were 0.91 (95%CI: 0.88-0.93), 0.64 (95%CI: 0.50-0.76), and 0.67 (95%CI: 0.52-0.79), respectively; and the corresponding specificity was 0.81 (95%CI: 0.75-0.85), 0.81 (95%CI: 0.25-0.85), and 0.96 (95%CI: 0.89-0.98), respectively. In prognosis analysis (6 studies, 198 patients), significant difference of overall survival was observed between high and low standardized uptake value groups (HR = 2.39, 95%CI: 1.57-3.63). Subgroup analysis showed that PET/CT was more sensitive than PET alone in evaluating liver metastasis of PC, 0.82 (95%CI: 0.48-0.98) and 0.67 (95%CI: 0.52-0.79), respectively. PET can be used as a valuable diagnostic and predictive tool for PC, but its effect in the staging of PC remains indeterminate.