Diffusion lacunae: a novel MR imaging finding on diffusion-weighted imaging for diagnosing placenta accreta spectrum

Area of Science:

• Radiology
• Obstetrics
• Medical Imaging

Background:

• Placenta accreta spectrum (PAS) poses significant risks during pregnancy.
• Accurate diagnosis of PAS is crucial for effective management and patient outcomes.
• Established MRI features for PAS diagnosis can be complex.

Purpose of the Study:

• To assess the diagnostic utility of novel diffusion-weighted imaging (DWI) findings for placenta accreta spectrum (PAS).
• To evaluate diffusion lacunae characteristics and T2 flow voids on MRI for PAS detection.

Main Methods:

• Retrospective analysis of 49 pregnant women with suspected PAS undergoing 1.5T placental MRI.
• Evaluation of diffusion lacunae (hypointense on DWI, hyperintense on ADC map) and T2 flow voids.
• Comparison of DWI findings with established MRI features and correlation with PAS diagnosis.

Main Results:

• Diffusion lacunae were significantly larger and more numerous in patients with PAS (p < 0.0001).
• Combined lacunae number and size achieved 83% sensitivity, 94% specificity, and 90% accuracy.
• T2 flow voids within lacunae demonstrated 88% sensitivity, 84% specificity, and 86% accuracy.

Conclusions:

• The number and size of diffusion lacunae on DWI are valuable indicators for PAS diagnosis.
• Presence of T2 flow voids within diffusion lacunae also contributes to accurate PAS diagnosis.
• These novel DWI findings enhance MRI's capability in diagnosing placenta accreta spectrum.