Evaluation of bone marrow transformation in hip of non?professional marathoners by MRI / 中华放射学杂志

ABSTRACT

Objective To observe the bone marrow signals of acetabulum and proximal femur of asymptomatic non?professional marathoners by 3.0 T magnetic resonance imaging (MRI) T1WI, and evaluate the bone marrow transformation, so as to obtain the effect of Marathon exercise on bone marrow composition and function. Methods The study group was randomly selected to participate in and complete the whole marathon at least once a year in the past two years. The training mileage of long?distance running was not less than 1 600 kilometers per year. There were no symptoms such as hip pain. There were no abnormalities in hip joint physical examination. The age of 22?53 years old. A total of 31 and 62 hips were evaluated. The control group was randomly selected 29 healthy persons (58 hip joints), aged 23?53 years, without hip pain and regular exercise. All subjects underwent hip joint MRI scan, and the hip joint MRI showed normal. At least 12 hours before MR scan, he did not engage in long?distance running or other sports. The bone marrow signal intensity of acetabulum and proximal femur in T1WI was compared with that of surrounding muscles and fat. The signal intensity was graded from low to high and evaluated by grade. The research group was divided into two groups according to the training years of marathon (running age). The running age of group A was more than 4 years and group B was less than 4 years. The distribution of bone marrow signal in proximal femur was also evaluated by a more intuitive 3?4 classification method. Mann?Whitney U test was used for statistical analysis. Results Bone marrow signal grading evaluation showed that there were significant differences in bone marrow signal grade distribution between the two groups (Z=-6.828, -4.779, -3.046,-5.266,-3.490,-5.053, P<0.05). In the study group, there were 14, 28 hips and 168 parts in group A, 17, 34 hips and 204 parts in group B, bone marrow signals were graded. There were significant differences in acetabulum, femoral neck and upper femoral shaft bone (Z=-2.202, -2.214, -2.730, P<0.05), but no significant differences in femoral head, trochanter and trochanter bone (Z=-0.886,-1.642,-0.711, P>0.05). To evaluate the classification of bone marrow signals in proximal femur, 62 cases of bone marrow signals in the study group were classified as follows 10 cases with type 1a, 24 cases with type 1b, 17 cases with type 2 and 11 cases with type 3. In the control group, 58 cases of bone marrow signals in proximal femur were classified as follows 2 cases with type 1a, 13 cases with type 1b, 26 cases with type 2 and 17 cases with type 3. There were significant differences between the two groups (Z=-4.003, P<0.05). Conclusion The T1WI signal intensity of asymptomatic non?professional marathoners′acetabulum and proximal femur bone marrow is lower than that of non?marathoners; the T1WI signal intensity of acetabulum, femoral neck and upper femoral shaft bone marrow of the elderly runners is lower; that is, marathon exercise has certain influence on the bone marrow signal of acetabulum and proximal femur, that is, the change of bone marrow signal in weight?bearing area has a certain phase with the amount of exercise.