Final answer:
MRI is the imaging of choice for detecting stress fractures, as it offers detailed images without ionizing radiation. Ultrasounds are the safest imaging option during pregnancy due to their non-invasive nature and lack of radiation.
Step-by-step explanation:
The imaging of choice for a stress fracture is magnetic resonance imaging (MRI). While X-rays are commonly used to image broken bones due to their high penetrating energy and ability to show the skeletal system, they may not always detect stress fractures immediately after an injury. MRIs, however, provide detailed images of both bones and soft tissues without using ionizing radiation, making it more suitable for detecting the subtle changes of a stress fracture.
When considering the safety of imaging studies during pregnancy, ultrasounds are the least invasive and do not use electromagnetic radiation, making them the safest option. This is particularly important as X-rays, CT scans, and PET scans involve ionizing radiation, which poses a higher risk to the developing fetus.