Type:
Educational Exhibit
Keywords:
Neoplasia, Metastases, Normal variants, Diagnostic procedure, Decision analysis, MR, Musculoskeletal system, Musculoskeletal spine, Musculoskeletal bone
Authors:
M. G. Chiarilli, A. Delli Pizzi, M. P. Febo, B. Cardinali, B. Consorte, A. Cifaratti, A. R. Cotroneo, D. Mastrodicasa, G. Cannataro; Chieti/IT
DOI:
10.26044/ecr2019/C-2445
Conclusion
BM components and location in normal red/yellow and pathologic marrow are responsible for different signals in MRI sequences: it is crucial to differentiate between normal and pathologic findings.
As general rule normal BM is hyperintense on T1w images as compared to muscle and intervertebral disc signals: red marrow is less hyperintense than yellow marrow.
Red and yellow marrow are slightly differentiated on T2W images.
On STIR red marrow is hyper-/iso-intense,
yellow marrow is hypo-/iso-intense.
BM variants possess normal signal intensity and symmetric distribution.
BM disorders are classified in reconversion,
infiltrative,
replacement and depletion disorders,
BM ischemia and edema,
and storage diseases.
Reconversion occurs in physiologic and pathologic stimuli; it occurs following the reverse sequence of physiologic conversion and MR signal is normal.
Infiltrative and replacement disorders are characterized by a hypointense signal on T1w images if compared to muscle and intervertebral disc signals; T2w and STIR signals are variable.
Yellow marrow replaces red marrow in depletion disorder: BM is hyperintense in both T1w and T2w images and hypointense in STIR.
BM ischemia is hypointense in T1w images and hyperintense in T2w images.
Double line sign is typical.
BM edema is unspecific finding and appears hypointense in T1w images and hyperintense in T2w and STIR.
More common storage diseases are Gaucher’s disease,
in which BM is hypointense in T1W images and hyperintense in T2w images,
and iron storage diseases,
in which BM is hypointense in all sequences.