Purpose or Case Report: Fat is a normal part of the human body, though can also be present in a variety of pathologic conditions. It is important to understand its physiologic distribution at various ages and appearance on multimodality imaging exams during growth. In addition, recognizing the presence of fat in tumors, in abnormal locations of the body, or in syndromic conditions is helpful in generating an accurate diagnosis. The purpose of this exhibit is to review the normal appearance and distribution of fat on ultrasound, CT, and MRI during different stages of development and to help the learner improve their knowledge and confidence when reporting cases concerning abnormalities of fat.
Methods & Materials: Learning objectives will include:
1. Understand the physiologic distribution of fat during normal development, including marrow and soft-tissue related changes during growth.
2. Identify techniques for evaluating both the normal and abnormal appearance of fat on ultrasound, CT, and MRI.
3. Develop a structured and age-based approach to assessing fat-containing lesions.
Results: The contents of this exhibit will discuss the normal and abnormal appearance of fat in the bone marrow, soft tissues, and parenchymal organs during development, as well as fat within discrete lesions. It will include assessing fat on ultrasound, CT, and MRI, including quantitative methods. A structured, pattern-based approach will be emphasized. Specific content will include:
1. Normal conversion of red marrow to fatty marrow during growth, and how to distinguish true lesions from residual red marrow using MR techniques.
2. Fat-containing soft tissue masses in pediatric radiology, such as lipoma, lipoblastoma, liposarcoma, teratoma, etc.
3. Assessment of fat in parenchymal organs, such as fatty infiltration of the liver, pathologic conditions of fat in the pancreas, and abdominal fat containing lesions.
4. Fat-containing lesions of the central nervous system.
5. Extremity-related abnormal fat, including muscular fatty infiltration, neonatal fat necrosis, and syndromic-related lipomatosis, such as macrodystrophia lipomatosa.
To enhance practical utility, a chart for lesions containing fat will be provided, with an age-based approach.
Conclusions: Through a comprehensive and structured approach to assessing fat by different imaging modalities and at various ages, this exhibit will help the learner recognize and be more comfortable assessing fat-containing lesions, as well as the significance of fat localization and distribution during development.