Apparent diffusion coefficient-based histogram analysis differentiates histological subtypes of periampullary...

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Histological subtype of periampullary adenocarcinoma impacts prognosis, with intestinal-type (IPAC) generally having a better outlook than pancreatobiliary-type (PPAC).
• Pre-operative differentiation of IPAC from PPAC is challenging, yet crucial for treatment planning.
• Apparent diffusion coefficient (ADC) histogram analysis offers a noninvasive, reproducible method for characterizing tissue.

Purpose of the Study:

• To evaluate the utility of volumetric ADC histogram analysis in distinguishing IPAC from PPAC.
• To determine if specific ADC histogram parameters can reliably differentiate between the two histological subtypes.

Main Methods:

• Retrospective analysis of 476 patients with suspected periampullary tumors undergoing 3.0 T MRI with diffusion-weighted imaging (b-values 800 and 1000 s/mm²).
• Volumetric histogram analysis of ADC values (mean, percentiles, min, max, kurtosis, skewness, entropy) was performed on 40 confirmed cases (17 IPAC, 23 PPAC).
• Statistical comparisons using Student's t-test or Mann-Whitney U test and receiver operating characteristic (ROC) curve analysis were employed.

Main Results:

• ADC histogram parameters derived from ADC₁₀₀₀, including mean, 5th, 25th, 50th, 75th, 90th, 95th percentiles, and ADCmax, were significantly lower in PPAC compared to IPAC (P < 0.05).
• No significant differences were observed between groups for ADC values derived from ADC₈₀₀.
• The 75th percentile of ADC₁₀₀₀ values demonstrated the highest diagnostic performance (AUC = 0.781) for differentiating IPAC from PPAC, with 91% sensitivity and 59% specificity.

Conclusions:

• Volumetric ADC histogram analysis, particularly at a b-value of 1000 s/mm², shows potential as a noninvasive tool for pre-operative differentiation of IPAC and PPAC.
• This imaging technique could aid in surgical planning and prognostic assessment for periampullary adenocarcinoma.