Evaluation of 18-FDG PET diagnostic capabilities for cancer screening in heart transplant patients, a retrospective study.

Evaluate 18-FDG positron emission tomography (PET) diagnostic capabilities for cancer screening in heart transplant patients. We conducted an anonymized retrospective observational study of heart transplant patients followed in the University Hospital of Montpellier, France. We analyzed 303 18-FDG PET from 158 patients. We compared demographic and clinical characteristics through uni- and multivariate analysis: in the cancer-free group, comparisons were made between the PET false positive (FP) group versus true negative (TN), and in the cancer group, comparisons were made between the PET false negative (FN) group versus true positive (TP). Out of the 303 exams, we found 245 TN, 26 TP, 26 FP and 6 FN. The sensitivity rate was calculated at 81%, the specificity rate at 90%, the positive predictive value at 50%, and the negative predictive value at 97%. The multivariate analysis showed an association between FP diagnosis and graft-PET delay (P value = .046, OR = 5.14, 95% CI [1.18-32.4]) and creatine reactive protein (CRP) ≥ 10 mg/L (P value = .042, OR = 4.21, 95% CI [1.02-17.2]). The estimated probability of FP by logit regression was 0.48 with 95% CI [0.21-0.77] when graft-PET delay ≥ 6 years and CRP ≥ 10 mg/L. No significative statistical link was found for the demographic or clinical characteristics in the FN group of patients with cancer, except for sex (all FN were men). 18-FDG PET performed very well in the follow-up of heart transplant patients for neoplasia screening, with better specificity than sensitivity. However, the study showed that almost 50% of FP can be predicted by considering only the graft-PET delay and CRP.

Functional PET Neuroimaging in Consciousness Evaluation: Study Protocol.

Ensuring a robust and reliable evaluation of coma deepness and prognostication of neurological outcome is challenging. We propose to develop PET neuroimaging as a new diagnostic and prognosis tool for comatose patients using a recently published methodology to perform functional PET (fPET). This exam permits the quantification of task-specific changes in neuronal metabolism in a single session. The aim of this protocol is to determine whether task-specific changes in glucose metabolism during the acute phase of coma are able to predict recovery at 18 months. Participation will be proposed for all patients coming for a standard PET-CT in our center in order to evaluate global cerebral metabolism during the comatose state. Legally appointed representative consent will be obtained to slightly modify the exam protocol: (1) 18F-fluorodeoxyglucose (18F-FDG) bolus plus continuous infusion instead of a simple bolus and (2) more time under camera to perform dynamic acquisition. Participants will undergo a 55-min fPET session with a 20% bolus + 80% infusion protocol. Two occurrences of three block (5-min rest, 10-min auditory stimulation and 10-min emotional auditory stimulation) will be performed after reaching equilibrium of FDG arterial concentration. We will compare the regional brain metabolism at rest and during the sessions of auditory and emotional auditory stimulation to search for a determinant of coma recovery (18 months of follow-up after the exam). Emotional auditory stimulation should induce an activation of: the auditory cortex, the consciousness areas and the neural circuitry for emotion (function to coma deepness). An activation analysis will be carried out to highlight regional brain activation using dedicated custom-made software based on Python statistical and image processing toolboxes. The association between activation levels and the Coma Recovery Scale-Revisited (CRS-R) will be assessed using multivariate analysis. If successful, the results from this study will help improve coma prognosis evaluation based on the pattern of neuronal metabolism at the onset of the pathology. The study protocol, rationale and methods are described in this paper.