EFFECT OF SLICE ACQUISITION DIRECTION ON IMAGE QUALITY IN THORACIC MRI

Objective: We tested the basic observation that imaging the heart and pericardium in systole improves image quality compared with that in di astole. Materials and Methods: Twenty consecutive patients and two vol unteers underwent sequential ECG-gated short TE transaxial prospective multislice SE MRI with both caudocranially and craniocaudally directe d slice prescriptions, keeping other imaging parameters constant. Imag es of the heart and pericardium were obtained in systole and diastole and examined by three independent reviewers for image quality. Results : In the lower mediastinum, cardiac structures and the pericardium wer e better seen in 49 of 57 individual evaluations when imaged in systol e, 15 of which were judged markedly better. Vascular structures and th e pericardium in the upper mediastinum were imaged equally well with b oth prescriptions. Conclusion: The findings suggest that in systole, t he more mobile heart can maintain a more consistent shape during the a cquisition of successive phaseencoding steps and preserve luminal flow void, factors critical to optimizing image quality in the transaxial plane.