Can diffusion-weighted imaging serve as a biomarker of fibrosis in pancreatic adenocarcinoma?
To assess the relationship between diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM)-derived quantitative parameters (apparent diffusion coefficient [ADC], perfusion fraction [f], Dslow, diffusion coefficient [D], and Dfast, pseudodiffusion coefficient [D*]) and histopathology in pancreatic adenocarcinoma (PAC).



Subjects with suspected surgically resectable PAC were prospectively enrolled in this Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board-approved study. Imaging was performed at 1.5T with a respiratory-triggered echo planar DWI sequence using 10 b values. Two readers drew regions of interest (ROIs) over the tumor and adjacent nontumoral tissue. Monoexponential and biexponential fits were used to derive ADC2b, ADCall, f, D, and D*, which were compared to quantitative histopathology of fibrosis, mean vascular density, and cellularity. Two biexponential IVIM models were investigated and compared: 1) nonlinear least-square fitting based on the Levenberg-Marquardt algorithm, and 2) linear fit using a fixed D* (20 mm2/s). Statistical analysis included Student's t-test, Pearson correlation (P < 0.05 was considered significant), intraclass correlation, and coefficients of variance.



Twenty subjects with PAC were included in the final cohort. Negative correlation between D and fibrosis (Reader 2: r = -0.57 P = 0.01; pooled P = -0.46, P = 0.04) was observed with a trend toward positive correlation between f and fibrosis (r = 0.44, P = 0.05). ADC2bwas significantly lower in PAC with dense fibrosis than with loose fibrosis ADC2b(P = 0.03). Inter- and intrareader agreement was excellent for ADC, D, and f.



In PAC, D negatively correlates with fibrosis, with a trend toward positive correlation with f suggesting both perfusion and diffusion effects contribute to stromal desmoplasia. ADC2bis significantly lower in tumors with dense fibrosis and may serve as a biomarker of fibrosis architecture.



1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:393-402.
New York Presbyterian-Columbia University Medical Center, Department of Radiology, New York, New York, USA.
Elizabeth M
0000-0002-4746-8415
EM
Hecht
New York Presbyterian-Columbia University Medical Center, Department of Radiology, New York, New York, USA.
Michael Z
MZ
Liu
New York Presbyterian-Columbia University Medical Center, Department of Radiology, New York, New York, USA.
Martin R
MR
Prince
New York Presbyterian-Columbia University Medical Center, Department of Radiology, New York, New York, USA.
Sachin
S
Jambawalikar
New York Presbyterian-Columbia University Medical Center, Department of Pathology, New York, New York, USA.
Helen E
HE
Remotti
New York Presbyterian-Columbia University Medical Center, Department of Pathology, New York, New York, USA.
Stuart W
SW
Weisberg
New York Presbyterian-Columbia University Medical Center, Department of Surgery, New York, New York, USA.
Donald
D
Garmon
Columbia University Mailman School of Public Heath, Department of Biostatistics, New York, New York, USA.
Sara
S
Lopez-Pintado
City of Hope, Department of Surgery, Duarte, California, USA.
Yanghee
Y
Woo
New York Presbyterian-Columbia University Medical Center, Department of Surgery, New York, New York, USA.
Michael D
MD
Kluger
New York Presbyterian-Columbia University Medical Center, Department of Surgery, New York, New York, USA.
John A
JA
Chabot
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000328:Adult; D000368:Aged; D000465:Algorithms; D015415:Biomarkers; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005355:Fibrosis; D064368:Healthy Volunteers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009038:Motion; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult
D015415:Biomarkers
diffusion weighted imaging (DWI); fibrosis; intravoxel incoherent motion (IVIM); pancreas; pancreas adenocarcinoma (PAC); stromal desmoplasia