Background
Ki‐67 proliferation index (PI) is important for providing information on tumor behavior, treatment response, and prognosis. Integrated positron emission tomography/magnetic resonance (PET/MR) may have the potential to assess Ki‐67 PI in patients with lung adenocarcinoma.
Purpose
To explore the value of simultaneous 18F‐fluorodeoxyglucose (18F‐FDG) PET/MR‐derived parameters in assessing the proliferation status of lung adenocarcinoma and to determine the best combination of parameters.
Study Type
Prospective.
Population
Seventy‐eight patients with lung adenocarcinoma and with Ki‐67 PI.
Field Strength/Sequence
3.0 T, simultaneous PET/MRI including diffusion‐weighted imaging (DWI) and 18F‐FDG PET.
Assessment
DWI‐derived parameters, namely, apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo diffusion coefficient (D*), perfusion fraction (f), diffusion heterogeneity index (α), and distributed diffusion coefficient (DDC); and PET‐derived parameters, namely, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolytic volume (TLG), were calculated and compared between the high (>25%) and low (≤25%) Ki‐67 PI groups. The correlations between PET‐derived parameters and DWI‐derived parameters were analyzed.
Statistical Tests
Student's t‐test, Mann–Whitney U test, chi‐square test, and receiver operating characteristic (ROC) curves. A P‐value <0.05 was considered statistically significant.
Results
The SUVmax, MTV, TLG, ADC, D, and DDC values were significantly different between the high (N = 35) and low Ki‐67 PI groups (N = 43). D, SUVmax, and MTV independently predicted the Ki‐67 PI status. The combination of D, SUVmax, and MTV had the largest area under the ROC curve (AUC = 0.900), which was significantly larger than the AUC alone of DDC (AUC = 0.725), SUVmax (AUC = 0.815), MTV (AUC = 0.774), or TLG (AUC = 0.783). The perfusion fraction did not correlate with SUVmax, MTV, or TLG (r = −0.03, −0.11, and −0.04, respectively; P = 0.786, 0.348, and 0.733).
Data Conclusion
The combination of D, SUVmax, and MTV may predict Ki‐67 PI status. No correlation was observed between perfusion parameters and metabolic parameters.
Level of Evidence
1
Technical Efficacy
Stage 2