This study evaluates whether a 7-day ketogenic dietary regimen before 2-\[18F\]FDG PET/CT can improve the diagnostic accuracy of imaging in adults with suspected or histologically confirmed lepidic-predominant lung adenocarcinoma (LPA). LPA frequently shows low glucose metabolism and may yield false-negative FDG PET/CT results. Approximately 30 participants will undergo a tailored ketogenic diet for 7 days before PET/CT. Imaging results will be compared with histopathology and additionally assessed against literature-reported diagnostic performance and a matched retrospective institutional cohort.
Written informed consent.
Age 18 years or older.
CT evidence of a lung nodule suspicious for LPA or lung biopsy positive for LPA.
Target nodule diameter at least 10 mm.
Not suitable for prolonged imaging procedures.
Renal failure.
Type 1 diabetes mellitus.
Pancreatitis.
Single group
Ketogenic diet
BehavioralTailored low-glucose/high-fat ketogenic dietary regimen administered for 7 consecutive days before 2-\[18F\]FDG PET/CT. Compliance will be assessed by clinical review, laboratory testing, and urinalysis on the day of PET/CT.
2-[18F]FDG PET/CT
Diagnostic testFDG PET/CT performed after completion of the 7-day ketogenic diet. Images will undergo visual and semiquantitative assessment, including comparison of target nodule uptake with mediastinal blood pool background and measurement of SUVmax.
Diagnostic performance of 2-[18F]FDG PET/CT after a 7-day ketogenic diet
Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of visual and semiquantitative 2-\[18F\]FDG PET/CT for identification of LPA after a 7-day ketogenic diet. Histopathological diagnosis will be used as the reference standard. Visual assessment will classify scans as positive when target nodule uptake is equal to or greater than mediastinal blood pool background; semiquantitative assessment will include SUVmax-based evaluation.
Comparison of diagnostic performance with literature-reported values
Comparison of study estimates of sensitivity, specificity, accuracy, positive predictive value, and negative predictive value with values reported in the literature using Z-test analysis
Comparison of diagnostic performance with a matched retrospective institutional cohort
Comparison of sensitivity, specificity, accuracy, positive predictive value, and negative predictive value between the prospective ketogenic-diet cohort and a matched retrospective institutional cohort. Semiquantitative PET metrics, including SUVmax, will also be compared between cohorts.
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