For a pulmonary nodule, what is the best imaging study to use for repeat imaging?

When assessing a pulmonary nodule for repeat imaging, a CT of the chest without contrast is the most effective choice. This is primarily because CT scans provide detailed cross-sectional images of the lungs, allowing for better visualization of the nodule's characteristics, such as size, margins, and internal structure. Such detail is crucial in evaluating changes over time, which can help determine whether the nodule is benign or malignant.

In contrast, a chest X-ray lacks the sensitivity and specificity required for thorough evaluation of small nodules and may miss changes that a CT scan would detect. An MRI of the chest, while excellent for soft tissue characterization, is not as routinely used for lung nodules due to the high prevalence of motion artifacts and the need for specific indications. Ultrasound of the chest is generally not useful in assessing pulmonary nodules because it does not penetrate bone and air-filled structures effectively and is more suitable for examining pleural effusions or guiding biopsies in particular scenarios. Thus, CT of the chest without contrast stands out as the optimal imaging method for monitoring pulmonary nodules.