Scan time reduction in diffusion-weighted imaging of the pancreas using a simultaneous multislice technique with different acceleration factors: How fast can we go?

OBJECTIVES

To investigate the feasibility of simultaneous multislice-accelerated diffusion-weighted imaging (sms-DWI) of the pancreas with different acceleration factors and its influence on image quality, acquisition time and apparent diffusion coefficients (ADCs) in comparison to conventional sequences.

METHODS

DWI of the pancreas was performed at 1.5T in ten healthy volunteers and 20 patients with sms-accelerated echo-planar DWI using two different sms-acceleration factors of 2 and 3 (sms2/3-DWI). These DWI sequences were compared to conventional DWI (c-DWI) in terms of image quality parameters (5-point Likert scale) and ADC measurements.

RESULTS

c-DWI and sms2-DWI offered equivalently high overall image quality (4 [1; 5]) with scan time reduction to one-third (c-DWI: 173 s, sms2-DWI: 56 s). Sms3-DWI showed significantly poorer overall image quality (3 [1; 5]; p < 0.0001). ADC values were significantly lower in sms3-DWI compared to c-DWI in the pancreatic body and tail (body: c-DWI 1.4 x 10 mm/s, sms3-DWI 1.0 x 10 mm/s, p = 0.028; tail: c-DWI 1.3 x 10 mm/s and sms3-DWI 1.0 x 10 mm/s, p = 0.014).

CONCLUSIONS

Accelerated multislice DWI of the pancreas offers high image quality with a substantial reduction of acquisition time. Lower ADC values in multislice DWI should be considered in diagnostic reading.

KEY POINTS

• Simultaneous multislice-accelerated diffusion-weighted imaging (sms-DWI) promises scan time minimisation. • Sms-DWI of the pancreas offers diagnostic image quality in volunteers and patients. • Sms-DWI with an acceleration factor of 2 offers high image quality. • Higher acceleration factors in sms-DWI do not provide sufficient diagnostic image quality. • ADC values may be lower in sms-DWI.