Lung MRI at 1.5 and 3 Tesla: observer preference study and lesion contrast using five different pulse sequences

Area of Science:

• Radiology
• Medical Imaging
• Magnetic Resonance Imaging

Background:

• Lung MRI is crucial for diagnosing pulmonary conditions.
• Optimizing MRI pulse sequences and field strengths is essential for enhancing image quality and lesion conspicuity.
• Previous studies have explored various sequences for lung imaging, but direct comparisons at different field strengths are limited.

Purpose of the Study:

• To compare the image quality and lesion contrast of five different lung MRI pulse sequences at 1.5 T and 3 T.
• To evaluate the performance of sequences such as 3D volumetric interpolated breath-hold examination (VIBE), true fast imaging with steady-state precession (TrueFISP), half-Fourier single-shot turbo spin-echo (HASTE), short tau inversion recovery (STIR), and T2-weighted turbo spin-echo (TSE).

Main Methods:

• Lung MRI was performed on healthy volunteers and porcine lungs in a phantom at 1.5 T and 3 T using five distinct pulse sequences.
• Simulated lung pathology (nodules and infiltrates) was created in the phantom.
• Three blinded radiologists assessed image quality, including anatomical delineation, lesion conspicuity, and artifacts.
• Quantitative measurements of lesion contrast (CNODULES and CINFILTRATES) were determined.

Main Results:

• No significant differences in sequence preference were observed between 1.5 T and 3 T for overall image quality.
• TSE was preferred for mediastinal visualization, TrueFISP for lung parenchyma in volunteers, and TSE in the phantom.
• VIBE demonstrated the best depiction of nodules, while HASTE excelled in delineating infiltrates.
• Lesion contrast generally increased at 3 T compared to 1.5 T for most sequences, with VIBE showing the highest nodule contrast and HASTE the highest infiltrate contrast.

Conclusions:

• The imaging characteristics of the evaluated lung MRI pulse sequences do not substantially differ between 1.5 T and 3 T.
• A higher lesion contrast, crucial for detecting abnormalities, can be expected at 3 T, suggesting its potential advantage for lung MRI.