What is a disadvantage of using thin slices in 2D MRA?

Using thin slices in 2D Magnetic Resonance Angiography (MRA) can lead to longer echo times (TE), which can indeed result in signal loss. This loss occurs because thinner slices require a higher spatial resolution, which often necessitates longer acquisition times. During these longer acquisition times, certain signals may decay, particularly T2 signals, causing a reduction in the overall brightness or intensity of the vascular structures being imaged.

In the realm of MRI, echo time is related to how long it takes for the signals from tissues to be collected after the initial radiofrequency pulse is applied. When the echo time is prolonged due to the need for thinner slices, the chances of signal loss as a consequence of T2 and T1 relaxation times are increased. This is particularly crucial in MRA, as high-quality images are essential for accurately visualizing vascular anatomy and pathology.

Other potential issues associated with thin slices, such as increased susceptibility to motion artifacts or challenges in tissue suppression, while relevant, are secondary to the primary disadvantage regarding prolonged TE times and the resultant signal loss.