ABSTRACT
We retrospectively reviewed 733 cranial and 250 spinal T1-weighted MR images of patients younger than 24 years to evaluate the bone marrow changes. The signal intensity of the bone marrow on short-TR/TE images was compared with that of fat and normal muscles in the contiguous region and graded. The signal intensity of all anatomic segments was as low as that of muscle, or inferior, in all patients younger than 3 months because of hematopoietic tissue and probably greater amounts of trabecular bone. The first anatomic segments of cranial bone to become hyperintense were the zygomatic bone and mandibular symphysis, followed by the presphenoid bone, basisphenoid, basiocciput, calvaria, and the petrous apex. After 3 years of age, most patients demonstrated pneumatization of the sphenoid sinus. We describe the most interesting changes in the developing spine, which occur in the first 2 years of life. The morphology of the vertebral bodies was evaluated. The variability of the signal and the morphology of the disks were also evaluated. Regional patterns of bone marrow signal intensity and age-related differences should not be misinterpreted as a pathologic condition.
Subject(s)
Aging , Bone Marrow/anatomy & histology , Magnetic Resonance Imaging , Skull/anatomy & histology , Spine/anatomy & histology , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Reference Values , Retrospective StudiesABSTRACT
We retrospectively reviewed T1-weighted MR images of 381 patients aged from 7 days to 24 years to evaluate the bone marrow change in thoracic wall and shoulder, pelvis and proximal femur and upper and lower extremities. The patients included in the study were without history of bone marrow disease. A grade of from 1 to 4 was assigned to the marrow signal intensity of the examined anatomic segments. The signal intensity of all anatomic segments was as low as or lower than that of muscle in all patients younger than 2 months, reflecting underlying hematopoietic marrow. The first segments to become hyperintense were the epiphyseal/round bone ossification centers, followed by the phalanges, diaphysis, flat bones and metaphysis. Marrow signal intensity increased in all regions with age. While in the epiphysis, round bones and diaphysis bone marrow shows a diffuse and homogeneous increased signal intensity with age, in the sternum, ribs, scapulae, posterior ilium and metaphysis varying percentages of intermediate signal intensity are maintained. An orderly progression of red to yellow marrow was established.
