nsuring a fast scan time is particularly important for pediatric MRI. Often, cooperation of the patient is obtained for only a few minutes. Going beyond this limit will induce a need for anesthesia, with consequent risk and cost. Thus, clearly defined list ordered by priority of clinical questions for each exam is a must. In this presentation, four rapid exams will will be presented covering a the spectrum of pediatric body MR imaging.

Some musculoskeletal exams are well-suited to a targeted protocol. These include those obtained for infection, where a long-axis fluid sensitive scan and a short-axis post-contrast scan, each with fat suppression, can be accomplished rapidly. Another example of rapid MR for the musculoskeletal system is dysplastic hips (Fig. 1).¹ Often MRI is requested immediately upon completion of a reduction in the operating room and the targeted question is adequate positioning of the femoral head in the acetabulum. Here single shot imaging and dynamic steady state multiphase imaging in two planes suffice, yielding a 5 minute exam.

Cardiovascular exams may also be completed rapidly. One indication is evaluation of vascular rings and slings. A single post-contrast volumetric gradient echo scan recapitulates a CT angiogram, and can be accomplished quickly. Similarly, many post-operative congenital heart disease exams can be assessed in a single sequence exam. For instance, repaired tetralogy of Fallot patients present with goals of assessing (i) right ventricular volume, (ii) right ventricular ejection fraction, (iii) pulmonic regurgitation, and (iv) branch pulmonary artery stenosis (Fig. 2 and 3). A single contrast-enhanced time-resolved volumetric phase contrast exam (4D flow) can quantitatively achieve all goals.^2-3

For abdominal imaging, many tumors can be assessed with a two sequence protocol: a volumetric T2 scan and a volumetric post-contrast scan. This entails 10 minutes of imaging. Similarly a definitive iron quantification exam can be accomplished in a volumetric multiecho gradient echo scan of the liver and a gated multiecho scan of the myocardium.⁴ As a further example, emergency department acute abdomen MRI is well suited to three planes of single shot T2-weighted imaging with and without fat suppression. As each plane can be completed in approximately one minute, the entire exam should be under ten minutes. As rapid access to the MR scanner is essential for emergency department exams, this presents a practical approach.⁵