Knee MRI patterns of bone marrow reconversion and relationship to anemia
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Published on: November 10, 2023
Felix M Gonzalez1, Jason Mitchell2, Erica Monfred2
1Department of Radiology, University of Maryland Medical Center, Baltimore, Maryland, USA Fgonzalez401@bellsouth.net.
Background:
Bone marrow changes are commonly encountered on knee magnetic resonance imaging (MRI). The clinical relevance of these changes, especially as they relate to anemia, has not been studied in a large patient series.
Purpose:
To determine if the extent of bone marrow reconversion (BMR) can assist the radiologist in making recommendations for further evaluation for underlying anemia.
Material And Methods:
This study included 457 patients who had knee MRI over a 2-year period. Bone marrow patterns in the distal femur, proximal tibia, and fibula were graded as follows: 1, homogeneous fatty marrow; 2, patchy red marrow in the distal femur; 3, patchy red marrow in the distal femur and tibia and/or fibula; and 4, complete BMR in the femoral, tibial, and/or fibular metaphyses.
Results:
There was a statistically significant difference (P < 0.001) between the hemoglobin concentration and BMR grades. In women, anemia (Hb ≤12.0 g/dL) was found in 31 of 127 (24%) patients with grade 1, 31 of 83 (37%) with grade 2, 24 of 64 (37%) with grade 3, and 12 of 24 (50%) with grade 4. In men, anemia (Hb ≤13.0 g/dL) was found in 33 of 125 (26%) patients with grade 1, 12 of 19 (63%) with grade 2, five of 14 (36%) with grade 3, but not in the one patient with grade 4.
Conclusion:
Women demonstrating marrow changes of a grade 4 BMR pattern should get a laboratory assessment for anemia.
Insights
Bone marrow reconversion (BMR) on knee MRI correlates with anemia. Women with grade 4 BMR patterns require laboratory assessment for anemia.
Area of Science:
- Radiology
- Hematology
- Bone Marrow Imaging
Background:
- Bone marrow changes are frequently observed in knee MRI scans.
- The clinical significance of these bone marrow changes, particularly in relation to anemia, has been understudied in large patient cohorts.
Purpose of the Study:
- To investigate the correlation between the extent of bone marrow reconversion (BMR) and anemia.
- To determine if BMR grading on knee MRI can aid radiologists in recommending further evaluation for underlying anemia.
Main Methods:
- A retrospective analysis of 457 knee MRI scans performed over two years.
- Bone marrow patterns were graded from 1 (fatty marrow) to 4 (complete BMR) in the distal femur, proximal tibia, and fibula.
Main Results:
- A significant association (P < 0.001) was found between hemoglobin levels and BMR grades.
- Anemia prevalence increased with higher BMR grades in women, reaching 50% in grade 4.
- Anemia was also observed in men with higher BMR grades, though less consistently than in women.
Conclusions:
- A grade 4 BMR pattern on knee MRI in women warrants laboratory investigation for anemia.
- BMR grading on knee MRI may serve as a useful indicator for potential anemia.
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