Diagnostic value of arterial spin labeling perfusion MRI in the differentiation of parotid gland tumors: correlation with histopathology.

BACKGROUND

Overlapping signal intensities in conventional MRI limit parotid tumor characterization, necessitating advanced techniques like arterial spin labeling (ASL) to assess physiological parameters such as vascularity.

OBJECTIVES

To evaluate the diagnostic performance of ASL in differentiating parotid gland tumors by quantifying tumor blood flow ASLm (mean) and ASLmax (maximum) and determining optimal cutoff values correlated with histopathological findings.

METHODS

Forty-seven patients (20 pleomorphic adenomas [PA], 20 Warthin tumors [WT], 7 malignant) underwent standardized 1.5 T MRI protocols and ASL prior to parotidectomy. Quantitative ASL values were obtained from lesions and contralateral tissue. Statistical comparisons and ROC analyses were performed to identify diagnostic cutoff values.

RESULTS

ASLm and ASLmax values were higher in WT compared to PA (p < 0.01). No significant side-to-side differences were found in PA and malignant groups. For PA differentiation, ASLm and ASLmax yielded AUCs of 0.766 (p = 0.002) and 0.742 (p = 0.005), respectively. For WT differentiation, both parameters showed excellent performance, yielding AUCs of 0.774 (p < 0.001) and 0.769 (p = 0.002).

CONLUSIONS: While ASL perfusion MRI effectively differentiates common benign parotid tumors, its limitations in malignancy evaluation necessitate its integration into a multiparametric MRI protocol for a more reliable preoperative diagnosis.