Differentiation Of And Benign From Malignant Heart Lesions: The Feasibility Of Fluorine-18 Flflflfluorodeoxyglucose Positron Emission Tomography CT And Searching For The Reasonable Patient Preparation Protocol

1.Objective1.1 To probe the clinical utilization of Fluorine-18 fluorodeoxyglucose positron emissiontomography CT ( 18F-FDG PET/CT ) in diagnosis of malignant from nonmalignant heart andpericardium lesions, in order to assess the feasibility of 18F-FDG PET-CT for the differentiationof malignancy from benign manifested as heart and pericardium lesions,1.2 To find out the optimal cut-off value of maximum standard uptake values ( SUVmax ) andSUVmax lesion/blood for diagnosing the heart and pericardium lesions, than calculate thediagnostic sensitivity, specificity, accuracy of CT and PET-CT respectively. To make a 18F-FDGPET/CTdiagnostic criteria for heart and pericardium lesions by comprehensive analysis.2.Materials and Methods2.1 Object of studyA total of 29 cases ( malignancy: benign = 17: 12 ) with cardiac and pericardial lesions wereanalyzed in the present study, all of which were pathologically or clinically confirmed.2.2 FDG-PET/CT scanning2.2.1 Preparation for examination2.2.2 Scanning methodsAll patients were examined by 18F-FDG PET/CT and enhancement CT scan.2.2.2 Image analysisAll lesions were evaluated semi-quantitatively using maximum standard uptake values (SUVmax) and SUVmax lesion/blood, and the density of the heart and pericardium lesions andthe relation with surrounding tissues were evaluated. To find out the optimal cut-off value ofmaximum standard uptake values ( SUVmax ) and SUVmax lesion/blood for diagnosing theheart and pericardium lesions, Than calculate the diagnostic sensitivity, specificity, accuracy ofCT and PET-CT respectively.2.2.3 Statistical MethodsAll the measurement data was performed by the Normal Test. The differences of SUVmaxand SUVmax lesion/blood of benign between malignant lesions were analyzed byIndependent-Samples T Test or T'Test ( Normal ), or Mann-Whitney U Test ( Non-normaldistribution ). The statistic difference in sensitivity, specificity, accuracy, positive predictivevalue and negative predictive value of CT and PET/CT were compared by x2 test. Thestatistically significant difference was set at P<0.05. All the statistical analysis was made usingSPSS 13.0 software package.3.ResultsThe SUVmax of the benign lesions ranged from 0.5 to 7.4 (mean 2.26±1.82), and theSUVmax of the malignancy ranged from 2.6 to 21.2 (mean 8.37±5.20). The showed significantdifference ( t = 3.473, P = 0.000), the SUVmax Lesion/Blood of malignancy 1.15±1.06 andbenign 4.24±2.02 also prohibited significant difference(t = 4.842, P = 0.000).The optimal cut-off value of SUVmax is 3.5 and SUVmax Lesion/Blood is 1.8～2.2.The sensitivity, specificity, accuracy of CT and PET-CT were 64.7% ( 11/17 ), 75.0%( 9/12 ), 69.0% ( 20/29 ) and 100.0% ( 17/17 ), 83.3% ( 10/12 ), 93.1% ( 27/29 ) respectively.There was a significant differenec between CT and PET/CT in accuracy (P = 0.016)(McNemarTest).4.Conlusion18F-FDG PET-CT can correctly predict benignity or malignancy of cardiac and pericardiallesions. 1. ObjectiveMyocardial 18F-FDG uptake in PET scans in patients prepared by the usual fasting protocolmay result in difficulties in interpretation because variable uptake may yield false-positive resultsregarding mediastinal abnormalities. We aimed to analyze, retrospectively, the effect of diet onmyocardial FDG uptake.2. Materials and Methods2.1 Object of studyA total of 30 cases with cardiac and pericardial lesions were performed by PET/CT.2.2 FDG-PET/CT scanning2.2.1 Preparation for examinationThe "fasting" group comprised 17 consecutive patients before a clinical change in thepatient preparation protocol. The "new diet" group comprised 60 consecutive patients after theclinical protocol change who were directed to consume a very high-fat, low-carbohydrate,protein-permitted diet before FDG injection. All patients were given a questionnaire that wasused to verify diet adherence.2.2.2 Statistical MethodsAll the measurement data was performed by the Normal Test. The differences of SUVmaxand the blood glucose level of "fasting" group between The "new diet" group were analyzed byIndependent-Samples T Test or T'Test ( Normal ), or Mann-Whitney U Test ( Non-normaldistribution ). All the statistical analysis was made using SPSS 13.0 software package. 3. ResultsThe SUVmax of the "fasting" group ranged from 2.2 to 19.3 (median 3.1), and the SUVmaxof the"new diet" group ranged from 0.7 to 3.4 (median 2.1). The showed significant differenceby Mann-Whitney U Test ( Z = -3.333, P = 0.001<0.01),The blood glucose level of the "fasting" group ranged from 3.7 to 9.0 (mean 6.73±1.77),and the lood glucose level of the"new diet" group ranged from 4.2 to 8.6 (mean 5.82±1.05). Theshowed significant difference by t Test ( t = 1.746,P = 0.092),4. ConlusionA very high-fat, low-carbohydrate, protein-permitted diet before FDG injection suppressesmyocardial FDG uptake. This should facilitate definition of mediastinal abnormalities on FDGPET. It is a more reasonable patient preparation protocol for the patients with heart andpericardium lesions.