Useful internal standards for distinguishing infiltrative marrow pathology from hematopoietic marrow at MRI

Abstract

The objective of this study was to establish internal standards on MRI differentiating infiltrative marrow pathology from hematopoietic marrow. The T1-weighted images of 74 patients (51 biopsy-proven; 23 clinical follow-up) were reviewed retrospectively. The relative signal intensity of bone marrow was compared to adjacent skeletal muscle (n = 65) and/or nondegenerated intervertebral disk (n = 53). Twenty foci were hyperintense compared to muscle, of which 17 (85%) cases represented normal red marrow (P < .0001); 45 were isointense or hypointense compared to muscle, of which 44 (98%) represented infiltrative marrow processes (P < .0001). Twelve were hyperintense compared to disk, of which 12 (100%) represented normal red marrow (P < .0001); 41 were isointense or hypointense compared to disk, of which 40 (98%) represented infiltrative marrow processes (P < .0001). On T1-weighted spin-echo MRI, skeletal muscle and intervertebral disk may serve as internal standards for differentiating infiltrative pathology from normal hematopoietic marrow. Marrow lesions that are relatively isointense or hypointense to muscle and/or disk should not be considered normal hematopoietic marrow.

Characterization of hematopoietic bone marrow in male professional cyclists by magnetic resonance imaging of the lumbar spine

“…In T1-w SE sequences that are sensitive to fat, the SI is therefore lower as compared to yellow marrow (3). Similar to findings in leukemia and other diseases that lead to increased bone marrow cellularity (17), hematopoietic hyperplasia results in a further decrease of the T1 SI becoming iso-or hypointense to that of a normal disk (4). The TIRM sequence combines two major advantages that make this sequence favorable for bone marrow imaging.…”

Quantitative and Semiquantitative Evaluation of Erythropoietin-Induced Bone Marrow Signal Changes in Lumbar Spine MRI in Patients with Tumor Anemia

“…Hematopoietic (red) marrow consists of approximately 40% water, 40% fat and 20% protein, while yellow marrow contains 15% water, 80% fat and 5% protein [23,24]. Hematopoietic growth factors induce marrow hyperplasia [25,26]. After the administration of growth factors, one expects the MRI to resemble those seen in diffuse marrow diseases, such as leukemia, which cause cells to accumulate within the marrow space.…”

“…Hence, MRI is a very sensitive method to detect bone marrow signal changes which are characterized by signal decrease in T1-w SE and corresponding augmentation in OPP and Turbo-STIR ( fig. 3a-c) [1,2,4,7,[23][24][25][26][27][28][29].…”

Bone Marrow

“…Since most marrow lesions (benign or malignant) contain more free water than either hematopoietic or fatty marrow, they appear brighter than marrow on T2-W sequences [ 7 ] (recall that normal red marrow in children older than 2 or 3 years is brighter than muscle or non-degenerated intervertebral disks [ 44 ]). Marrow lesions have a longer T1 relaxation time and therefore appear isointense or hypointense compared to muscle on T1-W imaging and conspicuously hypointense against a background of the hyperintense yellow marrow in adults, adolescents, and older children [ 16 ].…”