Accuracy Of Positron Emission Tomography Research Articles

Value of PET/MRI for assessing tumor resectability in NSCLC-intra-individual comparison with PET/CT.

The purpose of this study was to compare the diagnostic accuracy of positron emission tomography (PET)/MRI with PET/CT for determining tumor resectability of non-small cell lung cancer (NSCLC). Sequential trimodality PET/CT/MRI was performed in 36 patients referred with the clinical question of resectability assessment in NSCLC. PET/CT and PET/MR images including T1 weighted sequence (T1-Dixon) and respiration gated T2 weighted sequence (T2-Propeller) were evaluated for resectability-defining factors; i.e. longest diameter of the tumor, minimal tumor distance to the carina, mediastinal invasion, invasion of the carina, pleural infiltration, pericardial infiltration, diaphragm infiltration, presence of additional nodules. There was no significant difference of maximal axial diameter measurements of the primary lung tumors and narrow limits of agreement in Bland-Altman analysis ranging from -11.1 mm to + 11.8 mm for T2-Propeller and from -14.3 mm to + 13.8 mm for T1-Dixon sequence. A high agreement of PET/MR with PET/CT for the different resectability-defining factors was observed (k from 0.769 to 1.000). There was an excellent agreement of T2-Propeller sequence and CT for additional pulmonary nodule detection (k of 0.829 and 0.833), but only a moderate and good agreement using T1-Dixon sequence (k of 0.484 and 0.722). In NSCLC the use of PET/MRI, including a dedicated pulmonary MR imaging protocol, provides a comparable diagnostic value for determination of tumor resectability compared to PET/CT. Our findings suggest that whole body PET/MRI can safely be used for the local staging of NSCLC patients. Further studies are warranted to determine whether it is feasible to integrate an imaging sequence in a whole body PET/MRI setting with the potential advantage of detection of liver or brain metastases.

PET and Neck Ultrasound for the Detection of Cervical Lymphadenopathy in Patients with Lung Cancer and Mediastinal Lymphadenopathy

Background: Cervical lymph nodes are frequently involved in patients with lung cancer and indicate inoperability. Some guidelines recommend neck ultrasound (NUS) in patients with bulky mediastinal lymphadenopathy. Positron emission tomography (PET) is indicated for patients with potentially curable disease. Objectives: We aimed to assess the diagnostic yield of NUS and the diagnostic accuracy of PET for cervical lymphadenopathy in this group with a high pre-test probability of N3 disease. Methods: Records of all patients with lung cancer who underwent an NUS over a consecutive 5-year period were reviewed. Only patients with mediastinal lymphadenopathy on computerised tomography (CT) were included. The diagnostic accuracy of PET was assessed with NUS-guided fine needle aspiration cytology used as the reference test. Results: During the study period, 123 patients met the inclusion criteria. Malignant cervical lymphadenopathy was confirmed in 49/123 (39.8% [95% CI 31.1–49.1]). PET-CT had a specificity of 81.1%, sensitivity of 87.5%, negative predictive value of 96.8% and positive predictive value of 50% for the detection of cervical lymphadenopathy, and it contributed no additional staging information in the neck area. Overall, PET led to a change in management in only 2.2% of cases. Conclusion: A significant proportion of patients with lung cancer and mediastinal lymphadenopathy have cervical lymphadenopathy detected by NUS. In this group of patients, PET offers minimal additional value in staging and management.

Accuracy of 11C-choline positron emission tomography in differentiating glioma recurrence from radiation necrosis: A systematic review and meta-analysis.

Distinguishing glioma recurrence from the necrosis after radiation therapy and/or chemotherapy is a crucial clinical issue, for the different diagnosis will lead to divergent treatments. The accurate judgment is barely achieved by conventional imaging methods. We therefore assume it is of need to exert a meta-analysis to evaluate the diagnostic accuracy of 11C-choline positron emission tomography (PET), to achieve this goal. We searched the PubMed, Embase, and Chinese Biomedical databases comprehensively to select eligible studies and assessed the quality of each article included (up to May 31, 2018). Fixed-effects models were used. Summary diagnostic accuracy of 11C-choline PET was obtained from pooled analysis. Five articles comprising 6 studies with total 118 patients (134 scans) were enrolled for the meta-analysis. There was no heterogeneity or publication bias among the included studies. The pooled sensitivity and specificity were 0.87 (95% confidence interval [CI]: 0.78, 0.93) and 0.820 (95% CI: 0.69, 0.91), respectively. The pooled diagnostic odds ratio was 35.50 (95% CI: 11.70, 107.75). The area under the curve was 0.9170 (95% CI: 0.8504, 0.9836), with Q* index equaling to 0.8499. The diagnostic accuracy of each subgroup showed no statistical differences with that of the overall group. This meta-analysis indicated 11C-choline has high diagnostic accuracy for the identification of tumor relapse from radiation induced necrosis in gliomas.

Fluorodeoxyglucose-positron emission tomography staging can replace bone marrow biopsy in Hodgkin's lymphoma. Results from Brazilian Hodgkin's Lymphoma Study Group

ObjectiveTo investigate, in a large prospective multicenter study, whether 2-[18F]-fluoro-2-deoxy-d-glucose-positron emission tomography is sufficiently accurate to identify clinically important bone marrow involvement by Hodgkin's lymphoma to replace routine bone marrow biopsy in a developing tropical country. MethodsPatients newly diagnosed with Hodgkin's lymphoma were recruited from six cancer centers in Brazil. All were staged by the results of positron emission tomography/computed tomography that were centrally reviewed and by iliac crest bone marrow biopsy. Patients were classified as having marrow disease if they had lymphoma identified by marrow biopsy histology or had focal 2-[18F]-fluoro-2-deoxy-d-glucose marrow uptake that resolved following chemotherapy. ResultsA total of 246 participants were recruited from six different centers and 62 (25.2%) were judged to have Hodgkin's lymphoma in the bone marrow. Positron emission tomography and biopsies were concordant in 206 patients (83%). Positron emission tomography correctly identified marrow disease in 59/62 patients (95.1%) and marrow biopsy in 25/62 patients (40.3%). In 22/62 (35.4%) patients, the two techniques were concordant in the diagnosis of marrow involvement. Of the forty discordant results, positron emission tomography found bone marrow involvement in 37 patients, upstaging 22 to stage IV and having an impact on therapeutic decision in nine cases given their reallocation from early to advanced stage. Three false negative positron emission tomography results were obtained with bone marrow biopsy giving positive findings. All three cases were classified as stage IV regardless of bone marrow findings implying no modification in the clinical management. The sensitivity, specificity and accuracy of positron emission tomography for detecting bone marrow disease were 95%, 100% and 98% and for bone marrow biopsy they were 40%, 100% and 84%, respectively. ConclusionWe conclude that positron emission tomography can replace marrow biopsy in Brazilian patients with Hodgkin's lymphoma without compromising clinical management.

PET Assessment of Epicardial Intimal Disease and Microvascular Dysfunction in Cardiac Allograft Vasculopathy

BackgroundCardiac allograft vasculopathy (CAV) is a leading cause of graft failure and death after heart transplantation. Absolute myocardial blood flow (MBF) quantification using rubidium 82 (Rb-82) positron emission tomography (PET) could enable evaluation of diagnostically challenging diffuse epicardial and microvascular disease in CAV. ObjectivesThe authors aimed to evaluate Rb-82 PET detection of CAV. MethodsConsecutive transplant recipients undergoing coronary angiography were prospectively evaluated with PET, multivessel intravascular ultrasound (IVUS), and intracoronary hemodynamics. CAV was defined as International Society of Heart and Lung Transplantation CAV1–3 on angiography and maximal intimal thickness ≥0.5 mm on IVUS. ResultsForty patients (mean age 56 years, 4.8 years post-transplant) completed evaluation. CAV was detected in 32 patients (80%) by IVUS and 14 (35%) by angiography. PET correlated significantly with invasive coronary flow indices: r = 0.29, rate-pressure product–adjusted myocardial flow reserve (cMFR) versus coronary flow reserve; r = 0.28, relative flow reserve versus fractional flow reserve; and r = 0.37, coronary vascular resistance (CVR) versus index of microcirculatory resistance. Patients with CAV or microvascular dysfunction had reduced cMFR and stress MBF and increased CVR. Receiver operator characteristic curves demonstrated good accuracy of PET for CAV on IVUS (area under the curve 0.77 to 0.81) and optimal diagnostic cutoffs of cMFR <2.9, stress MBF <2.3, and CVR >55. Combined PET assessment for CAV yielded excellent >93% sensitivity (>65% specificity) for 1 abnormal parameter and >96% specificity (>55% sensitivity) for 2 abnormal parameters. ConclusionsRb-82 PET flow quantification has high diagnostic accuracy for CAV, with potential for noninvasive evaluation after heart transplantation.

73P PET and neck US for the detection of cervical lymphadenopathy in patients with lung cancer and mediastinal lymphadenopathy

Background: Cervical lymph nodes are frequently involved in patients with lung cancer and indicate inoperability. Some guidelines recommend neck ultrasound (NUS) in patients with bulky mediastinal lymphadenopathy. Positron emission tomography (PET) is indicated for patients with potentially curable disease. We aimed to assess the diagnostic yield of NUS and the diagnostic accuracy of PET for cervical lymphadenopathy among patients with suspected lung cancer and mediastinal lymphadenopathy. Methods: Records of all patients with lung cancer who underwent a NUS over a consecutive 5-year period were reviewed. Only patients with mediastinal lymphadenopathy on CT were included. The diagnostic accuracy of PET was assessed with NUS-guided fine needle aspiration cytology used as the reference test. Results: During the study period 123 patients met the inclusion criteria. Malignant cervical lymphadenopathy was confirmed in 39.8% (95% CI 31.1–49.1%). PET-CT had a specificity of 81.1%, sensitivity of 87.5%, negative predictive value of 96.8% and positive predictive value of 50% for the detection of cervical lymphadenopathy, and it contributed no additional staging information in the neck area. Overall, PET led to changes in management in only 2.2% of cases. Conclusions: A significant proportion of patients with lung cancer and mediastinal lymphadenopathy have cervical lymphadenopathy detected by NUS. In this group of patients PET offers minimal additional value in staging and management. Legal entity responsible for the study: Galway University Hospital Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.

PET/MRI

Magnet resonance imaging (MRI) is an excellent anatomical reference method for the combination with positron emission tomography (PET). But MRI does not produce data, which can be directly used for attenuation correction of PET data, potentially compromising quantitative accuracy of PET. Hybrid-positron emission tomography/computed tomography (PET/CT) is an established standard diagnostic tool, particularly for staging and restaging in oncology. Attenuation correction of PET data is performed with a µMAP derived from low-dose-CT, considered as a robust method. Using standardized MRI-sequences, tissue classes are segmented and attenuation maps are obtained, based on empirical density values. In addition, new reconstruction algorithms and the possibility to acquire PET and MRI simultaneously with MRI-based motion correction are available. These advances have improved image quality and quantitative accuracy of the PET-data in PET/MRI. In numerous oncological studies PET/CT and PET/MR were rated as equal in their diagnostic performance. The combination of functional-metabolic PET and multiparametric MRI with excellent soft tissue contrast complement each other with regard to their diagnostic information in numerous tumor entities. The standard diagnostic workup for lung cancer is currently still based on PET/CT. In numerous tumor entities, the combination of PET/MRI can provide additional diagnostic information.

Positron Emission Tomography (PET) and PET/CT in Thyroid Cancer: A Systematic Review and Meta-Analysis

Background: Positron emission tomography (PET) and PET/CT are functional imaging methods that are widely used in diagnostic procedures in oncology. Objectives: The objective of this study was to assess the patient-relevant benefit of PET or PET/CT in patients with thyroid cancer based on a literature review and meta-analysis. Methods: A systematic review including studies that had been published until December 2013 was performed. To be included, studies had to prospectively investigate patients with thyroid cancer in a clinical setting of staging, restaging, or diagnosing tumour recurrence. Results: Out of 3,506 potentially relevant articles, 29 studies were included. No study directly evaluated the benefits of PET. Twenty-eight studies dealt with the diagnostic accuracy of PET or PET/CT, and 1 study evaluated the prognostic value of PET/CT. The authors showed that a positive result of PET/CT in restaging patients with differentiated thyroid cancer yielded a significant decrease in overall survival (hazard ratio, HR 5.01, CI 3.41–6.62). In patients with suspected recurrence of differentiated thyroid cancer, meta-analysis showed higher sensitivity of PET (89.7%, CI 78–99%) and PET/CT (94.3%, CI 87–97%) compared with conventional imaging (65.4%, CI 32–88%) and comparable results for specificity. Due to the low numbers of studies and patients, meta-analyses on medullary carcinoma did not produce meaningful results. Conclusion: The patient-relevant benefits of PET or PET/CT in thyroid cancer could not be evaluated satisfactorily based on the included studies. It remains unclear whether higher diagnostic test accuracy leads to changes in therapeutic strategies and better patient-relevant outcomes.

Assessing the absolute quantitative accuracy of Positron Emission Tomography for Cu-64 using traceable calibrated phantoms

Using uniform cylindrical phantoms containing calibrated solutions of 18F and 64Cu, we evaluated for the first time the accuracy with which the activity concentration of 64Cu can be quantified on an absolute basis using Positron Emission Tomography (with X-ray Computed Tomography, PET-CT). The scanner was first calibrated for 18F using the manufacturer's calibration protocol and a phantom with an activity concentration value traceable to the U.S. National standard. By using a similarly calibrated 18F solution phantom, we were able to determine a correction factor that can be applied to the 64Cu imaging data that gave a result that is consistent with 100% recovery with a combined standard uncertainty of 2%. We also demonstrate how a calibrated, solid phantom containing 68Ge as a long-lived 18F surrogate can be used to monitor and transfer the correction factor to other studies.

Comparison of Coronary CT Angiography, SPECT, PET, and Hybrid Imaging for Diagnosis of Ischemic Heart Disease Determined by Fractional Flow Reserve

ImportanceAt present, the choice of noninvasive testing for a diagnosis of significant coronary artery disease (CAD) is ambiguous, but nuclear myocardial perfusion imaging with single-photon emission tomography (SPECT) or positron emission tomography (PET) and coronary computed tomography angiography (CCTA) is predominantly used for this purpose. However, to date, prospective head-to-head studies are lacking regarding the diagnostic accuracy of these imaging modalities. Furthermore, the combination of anatomical and functional assessments configuring a hybrid approach may yield improved accuracy.ObjectivesTo establish the diagnostic accuracy of CCTA, SPECT, and PET and explore the incremental value of hybrid imaging compared with fractional flow reserve.Design, Setting, and ParticipantsA prospective clinical study involving 208 patients with suspected CAD who underwent CCTA, technetium 99m/tetrofosmin–labeled SPECT, and [15O]H2O PET with examination of all coronary arteries by fractional flow reserve was performed from January 23, 2012, to October 25, 2014. Scans were interpreted by core laboratories on an intention-to-diagnose basis. Hybrid images were generated in case of abnormal noninvasive anatomical or functional test results. Main Outcomes and MeasuresHemodynamically significant stenosis in at least 1 coronary artery as indicated by a fractional flow reserve of 0.80 or less and relative diagnostic accuracy of SPECT, PET, and CCTA in detecting hemodynamically significant CAD.ResultsOf the 208 patients in the study (76 women and 132 men; mean [SD] age, 58 [9] years), 92 (44.2%) had significant CAD (fractional flow reserve ≤0.80). Sensitivity was 90% (95% CI, 82%-95%) for CCTA, 57% (95% CI, 46%-67%) for SPECT, and 87% (95% CI, 78%-93%) for PET, whereas specificity was 60% (95% CI, 51%-69%) for CCTA, 94% (95% CI, 88%-98%) for SPECT, and 84% (95% CI, 75%-89%) for PET. Single-photon emission tomography was found to be noninferior to PET in terms of specificity (P < .001) but not in terms of sensitivity (P > .99) using the predefined absolute margin of 10%. Diagnostic accuracy was highest for PET (85%; 95% CI, 80%-90%) compared with that of CCTA (74%; 95% CI, 67%-79%; P = .003) and SPECT (77%; 95% CI, 71%-83%; P = .02). Diagnostic accuracy was not enhanced by either hybrid SPECT and CCTA (76%; 95% CI, 70%-82%; P = .75) or by PET and CCTA (84%; 95% CI, 79%-89%; P = .82), but resulted in an increase in specificity (P = .004) at the cost of a decrease in sensitivity (P = .001).Conclusions and RelevanceThis controlled clinical head-to-head comparative study revealed PET to exhibit the highest accuracy for diagnosis of myocardial ischemia. Furthermore, a combined anatomical and functional assessment does not add incremental diagnostic value but guides clinical decision-making in an unsalutary fashion.

The performance of 11C-Methionine PET in the differential diagnosis of glioma recurrence.

Despite the advancement of neuroimaging techniques, it often remains a diagnostic challenge to distinguish recurrent glioma from lesions representing treatment effect. Preliminary reports suggest that 11C-methionine Positron emission tomography (PET) can assist in diagnosing true glioma recurrence. We present here a meta-analysis to assess the accuracy of 11C-methionine PET in identifying recurrent glioma in patients who had undergone prior therapy. A comprehensive search of the PubMed, Embase and Chinese Biomedical (CBM) databases yielded 23 eligible articles comprising 29 studies listed prior to November 20, 2016, representing 891 patients. In this report, we assess the methodological quality of each article individually and perform a meta-analysis to obtain the summary diagnostic accuracy of 11C-methionine PET in correctly identifying recurrent glioma. The pooled sensitivity and specificity are 0.88 (95% CI: 0.85, 0.91) and 0.85 (95% CI: 0.80, 0.89), respectively, with an area under the curve (AUC) for the summary receiver-operating characteristic curve (SROC) of 0.9352. We conclude that 11C-methionine PET has excellent diagnostic performance for differentiating glioma recurrence from treatment effect.

18FDG-PET/CT for the detection of residual/recurrent in patients with head and neck cancer: A systematic review and meta-analysis.

e17502 Background: To evaluate the diagnostic accuracy of positron emission tomography (PET) and PET/computed tomography (CT) for detecting residual and/or recurrent local and regional disease in patients with head and neck cancer (HNC) following radiotherapy with or without chemotherapy. Methods: Studies about 18FDG-PET/CT for detecting residual or recurrent disease after treatment in patients with HNC were systematically searched in the MEDLINE and EMBASE databases. The Stata software was used to obtain pooled estimates of sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for 18FDG-PET/CT. Results: 31 articles bulled all inclusion criteria. The pooled sensitivity and specificity of PET and PET/CT for detecting residual or recurrent disease at the primary site was 88.7% and 89.6%, respectively. For residual or recurrent neck disease, the sensitivity and specificity were 75.9% and 92.0%, while for residual or recurrent localregional disease, the values were 89.6% and 87.8%. Conclusions: 18FDG-PET/CT has good diagnostic performance for the detection of residual and/or recurrent in HNC patients.

Comparison of Ultrasonography with CT, MRI and Pet in Cervical Lymph Node Staging of Head and Neck Cancer

The correct preoperative N staging is crucial for the patients with head and neck cancer to determine if the neck dissection is necessary or not. This study aims to compare imaging modalities for staging the neck of patients evaluated by CT/MRI/PET and ultrasonography with the histopathologicl findings of the neck dissection specimens. Between April 2015 and March 2017, 150 newly diagnosed head and neck patients received regular pretreatment images with CT/MRI/PET and Ultrasonography in one tertiary medical center were enrolled. There are 80 patients received the surgical treatment. Neck dissections were performed on 60 patients. In these patients, 26 received computed tomography (CT) examination, 46 have magnetic resonance image (MRI) images and all of them accepted cervical ultrasonography preoperatively. Meanwhile, Positron Emission Tomography (PET) was also done on 23 patients in the preoperative status. There are 55 cases of oral cavity cancer, 9 cases of hypopharyngeal cancers, 4 cases of oropharyngeal cancers, 2 cases of laryngeal cancer, 5 cases of parotid cancer, 3 cases of submandibular gland cancer, 2 cases of sinunasal cancer and one case of sublingual cancer. And one patient got synchronous palate and hypopharyngeal cancer. Understaging of the N stage of nasopharyngeal carcinoma (NPC) by Ultrasonography was noted due to the limitation of evaluating of retropharyngeal space lymph nodes. Based on histopathologyical findings of neck specimens or the N0 neck was confirmed after more than 6 months clinical follow-up, ultrasonography, MRI, CT and PET correctly identified cervical lymph node metastases with a sensitivity of 85.19% (specificity 81.13%), 71.43% (specificity 81.25%), 80% (specificity 100%) and 75% (specificity 80%) respectively. The accuracy of ultrasonography, MRI, CT and PET were 82.5%, 92.3%, 78.26% and 78.26%. Ultrasonography has the highest sensitivity of preoperative N staging in the image modalities in this study. It also has comparable specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy with MRI and PET. Since the ultrasound is convenient, has high approachability and is a noninvasive technique in the clinical practice, it should be considered to add in the preoperative survey of head and neck cancers routinely. The ultrasonography has the significant dominance to help head and neck surgeons to realize the disease more comprehensively before the operation and may change the decision making of the surgical plan.

PETPVE12: an SPM toolbox for Partial Volume Effects correction in brain PET – Application to amyloid imaging with AV45-PET

Positron emission tomography (PET) allows detecting molecular brain changes in vivo. However, the accuracy of PET is limited by partial volume effects (PVE) that affects quantitative analysis and visual interpretation of the images. Although PVE-correction methods have been shown to effectively increase the correspondence of the measured signal with the true regional tracer uptake, these procedures are still not commonly applied, neither in clinical nor in research settings. Here, we present an implementation of well validated PVE-correction procedures as a SPM toolbox, PETPVE12, for automated processing. We demonstrate its utility by a comprehensive analysis of the effects of PVE-correction on amyloid-sensitive AV45-PET data from 85 patients with Alzheimer's disease (AD) and 179 cognitively normal (CN) elderly. Effects of PVE-correction on global cortical standard uptake value ratios (SUVR) and the power of diagnostic group separation were assessed for the region-wise geometric transfer matrix method (PVEc-GTM), as well as for the 3-compartmental voxel-wise “Müller-Gärtner” method (PVEc-MG). Both PVE-correction methods resulted in decreased global cortical SUVRs in the low to middle range of SUVR values, and in increased global cortical SUVRs at the high values. As a consequence, average SUVR of the CN group was reduced, whereas average SUVR of the AD group was increased by PVE-correction. These effects were also reflected in increased accuracies of group discrimination after PVEc-GTM (AUC=0.86) and PVEc-MG (AUC=0.89) compared to standard non-corrected SUVR (AUC=0.84). Voxel-wise analyses of PVEc-MG corrected data also demonstrated improved detection of regionally increased AV45 SUVR values in AD patients. These findings complement the growing evidence for a beneficial effect of PVE-correction in quantitative analysis of amyloid-sensitive PET data. The novel PETPVE12 toolbox significantly facilitates the application of PVE-correction, particularly within SPM-based processing pipelines. This is expected to foster the use of PVE-correction in brain PET for more widespread use. The toolbox is freely available at http://www.fil.ion.ucl.ac.uk/spm/ext/#PETPVE12.

Tissue Probability-Based Attenuation Correction for Brain PET/MR by Using SPM8

Bone attenuation remains a methodological challenge in hybrid PET/MR, as bone is hard to visualize via magnetic resonance imaging (MRI). Therefore, novel methods for taking into account bone attenuation in MR-based attenuation correction (MRAC) are needed. In this study, we propose a tissue-probability based attenuation correction (TPB-AC), which employs the commonly available neurological toolbox SPM8, to derive a subject-specific $\mu$ -map by segmentation of T1-weighted MR images. The procedures to derive a $\mu$ -map representing soft tissue, air and bone from the New Segment function in SPM8 and MATLAB are described. Visual and quantitative comparisons against CT-based attenuation correction (CTAC) data were performed using two $\mu$ -values ( $0.135~\hbox{cm}^{ - 1}$ and $0.145~\hbox{cm}^{ - 1}$ ) for bone. Results show improvement of visual quality and quantitative accuracy of positron emission tomography (PET) images when TPB-AC $\mu$ -map is used in PET/MR image reconstruction. Underestimation in PET images was decreased by an average of $5 \pm 2$ percent in the whole brain across all patients. In addition, the method performed well when compared to CTAC, with maximum differences (mean $ \pm$ standard deviation) of $ - 3 \pm 2$ percent and $2 \pm 4$ percent in two regions out of 28. Finally, the method is simple and computationally efficient, offering a promising platform for further development. Therefore, a subject-specific MR-based $\mu$ -map can be derived only from the tissue probability maps from the New Segment function of SPM8.

Accuracy of Positron Emission Tomography as a Diagnostic Tool for Lead Endocarditis: Design of the Prospective Multicentre ENDOTEP Study.

Background: Rates of pacemaker implantation are steadily increasing and as patients are living longer, endovenous leads remain implanted for an extended period of time thereby increasing the risk of cardiac implantable electronic device (CIED) infection. Investigating fever of unknown origin in patients with implanted pacemakers can be challenging. Recently, 18F-fluorodeoxyglucose positron emission tomography/computerised tomography (18F-FDG-PET/CT) scanning has been used as a diagnostic tool for lead endocarditis in small studies. Objectives: ENDOTEP is a prospective and multicentre study designed to evaluate the accuracy of 18F-FDG-PET/CT scanning in the diagnosis of lead endocarditis. Methods: A total of 250 patients referred for pacemaker extraction due to suspicion of an infected device will be prospectively enrolled in six French regional centres for investigation and treatment of CIED infection. 18F-FDG-PET/CT scanning (index test) will be performed in each patient in the 48 hours preceding lead extraction. Bacteriological cultures (reference standard) will assess the presence of lead endocarditis, blind to 18F-FDG-PET/CT results. Enrolment started in June 2015 and is expected to end by June 2017. The primary objective will be to establish the sensitivity of the 18F-FDG-PET/CT scan for lead endocarditis. Secondary objectives will include other accuracy parameters, inter-observer agreement in the interpretation of 18F-FDG-PET/CT scanning, the influence of previous antibiotic therapy on 18F-FDG-PET/CT diagnostic accuracy and assessment of septic emboli associated to lead endocarditis. Conclusion: The ENDOTEP study will examine the ability of 18F-FDG-PET/CT scanning to avoid possible false-positive results, as is common using the current usual diagnostic strategy and may lead to unnecessary extraction of implants in patients with suspected lead infection.

Detecting Residual/Recurrent Head Neck Squamous Cell Carcinomas Using PET or PET/CT: Systematic Review and Meta-analysis.

To evaluate the diagnostic accuracy of positron emission tomography (PET) and PET/computed tomography (CT) for detecting residual and/or recurrent local and regional disease and distant metastases in patients with head and neck squamous cell carcinomas (HNSCCs) following radiotherapy with or without chemotherapy. A systematic review with no language restrictions was conducted using PREMEDLINE, MEDLINE, EMBASE, and Google Scholar. Only prospective studies with histopathological and/or clinical follow-up that assessed the diagnostic accuracy of PET and PET/CT in detecting residual and/or recurrent disease following radiotherapy with or without chemotherapy in patients with HNSCCs were included. Twenty-seven studies were identified. The pooled sensitivity and specificity of PET and PET/CT for detecting residual or recurrent disease at the primary site was 86.2% and 82.3%, respectively. For residual and recurrent neck disease, the sensitivity and specificity were 72.3% and 88.3%, while for distant metastases, the values were 84.6% and 94.9%. PET and PET/CT are highly accurate in detecting residual and/or recurrent HNSCC. PET/CT is more specific than PET alone. Specificity is also greater for scans performed more than 12 weeks after radiotherapy with or without chemotherapy. The authors support the use of PET/CT after 12 weeks posttreatment for the assessment of residual or recurrent disease.

Early differential diagnosis between Alzheimer's disease and dementia with Lewy bodies: Comparison between 18F-FDG PET and 123I-IMP SPECT

Both 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and 123I-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) have been used for the differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Less information is available, however, regarding the differential diagnosis of mild cognitive impairment (MCI) due to AD and MCI due to DLB. We examined nine AD patients (AD group), nine DLB patients (DLB group), eight MCI due to AD patients (MCI-AD group), and nine MCI due to DLB patients (MCI-DLB group) with FDG PET and IMP SPECT using a well-characterized normal database and a stereotactic extraction estimation method. In the AD and DLB groups, receiver operating characteristic (ROC) analysis in the occipital regions showed significant accuracy of both FDG PET and IMP SPECT for the differential diagnosis. In the MCI-AD and MCI-DLB groups, ROC analysis showed significant accuracy of only FDG PET for the differential diagnosis. Both FDG PET and IMP SPECT would be useful for the differential diagnosis between AD and DLB. For the differential diagnosis of MCI-AD versus MCI-DLB, FDG PET would be more useful than IMP SPECT.

The Utility of Positron Emission Tomography in Epilepsy.

The role of fludeoxyglucose F 18 positron emission tomography (PET) in the presurgical evaluation of patients with medically intractable epilepsy continues to be refined. The purpose of this study was to systematically review the literature to assess the diagnostic accuracy and utility of PET in this setting. Thirty-nine studies were identified through MEDLINE and EMBASE databases that met the inclusion criteria. In adult patients, PET hypometabolism showed a 56 to 90% agreement with seizure onset localized by intracranial electroencephalogram (pediatric: 21 to 86%). In temporal lobe epilepsy patients with good surgical outcome, PET displayed moderate to high sensitivity in localizing the seizure focus (range: 71 to 89%). The sensitivity increased by 8 to 23% when PET results were combined with magnetic resonance imaging or electroencephalogram. PET has been shown to affect patient management by improving the guidance of intracranial electrodes placement, altering the decision to perform surgery, or excluding patients from further evaluation.

Determination of the Input Function at the Entry of the Tissue of Interest and Its Impact on PET Kinetic Modeling Parameters.

Quantitative positron emission tomography (PET) imaging is employed with several measurement protocols all relying on the a priori determination of the input function (IF). The standard technique to determine IF is by blood sampling. However, a unique IF determined in a subject for a given PET study, either defined by sampling or in the images, and commonly utilized for all analyzed tissues in that study equally at rest and during interventions, is expected to provoke biases in the rate constants and in tissue blood volume. The determination of a specific IF at the site of the tissue to be analyzed enhances PET accuracy and renders PET imaging less invasive.