Quantitative evaluation of parotid gland dysfunction in patients with hyposalivation using magnetic resonance imaging mapping technique : Quantification of Parotid gland function using MRI

Abstract

Objective: This study aimed to assess the feasibility of quantitative magnetic resonance imaging (MRI) employing the multi-dynamic multi-echo (MDME) technique as a diagnostic modality for evaluating glandular dysfunction in patients with hyposalivation.

Methods: The MDME technique generated T1, T2, and proton density (PD) maps of the parotid gland, allowing for the simultaneous acquisition of values from the respective mappings. The Mann-Whitney U-test was used to compare the hyposalivation and control groups, and receiver operating characteristic (ROC) curve analysis was performed.

Results: A total of 71 patients who underwent MDME MRI were reviewed and categorized into hyposalivation patients (n = 32) and healthy controls (n = 25). The average T1, T2 and PD value of the gland in the hyposalivation group were 606.92 ms, 91.85 ms, and 82.52 pu, respectively, whereas those in the control group were 628.08 ms, 80.69 ms, and 91.12 pu, respectively. The T2 and PD values were significantly different between the hyposalivation and control groups. The cut-off T2 value was 85.75 ms (AUC = 0.8131, p < 0.0001) and the cut-off PD value was 81.55 pu (AUC = 0.7588, p = 0.0009).

Conclusions: T2 and PD values derived from the MDME technique demonstrated strong potential for detecting parotid gland dysfunction in hyposalivation patients. These findings suggest that MDME-based quantitative MRI mapping shows promise in evaluating hyposalivation of the parotid gland and could become a valuable diagnostic tool in clinical settings.

Keywords: Dry mouth; Hyposalivation; Magnetic resonance imaging; Multi-dynamic multi-echo sequence; Relaxation map; Salivary gland.

Fig. 1

(A) Schematic view of the region-of-interest (ROI) selection on a quantitative map using the multi-dynamic multi-echo technique. ROIs of 0.1 cm² with a square shape were established on the master quantitative map. (B) The T1 and T2 and proton density (PD) values were extracted simultaneously from each ROI and the average value was used for analysis. (ms, miliseconds; pu, percentage units)

Fig. 2

Flowchart showing patient selection and screening process. MRI, magnetic resonance imaging

Fig. 3

Comparison between patients with hyposalivation and control participants with respect to the T1 and T2 and proton density (PD) values. *Mann–Whitney U-test, 95% confidence interval. (ms, miliseconds; pu, percentage units)

Fig. 4

Receiver operating characteristic curve of T2 and proton density (PD) values for diagnosis of hyposalivation gland