Thoracolumbar Spinal MRI Evaluation Protocol

Thoracolumbar spinal MRI examinations were performed at the Department of Radiology, Carlanderska Hospital using a 1.5 T scanner (Signa, GE Healthcare, Chicago, IL, USA). The MRI protocol included sagittal T1-and T2-weighted sequences (Th1-S1). In the thoracic spine, a field of view of 360 × 360mm² and slice thickness of 3 mm was used. In the lumbar spine a field of view of 320 × 320mm² and slice thickness of 3.5 mm was utilized.
The MRI images were classified by a senior radiologist (> 15 years of experience) according to a predetermined standardized protocol. Disc degeneration was classified according to the Pfirrmann classification [23 (link)]. In the thoracic spine, no distinction between Pfirrmann grade 1 and grade 2 was made since the resolution of the images was not considered adequate for reliable differentiation between these grades. Vertebral and endplate changes were classified according to the Modic classification [24 (link)] and a modified Endplate defect score, adapted to our MRI protocol. The Endplate defect score [25 (link)] was modified where Type I-III (representing no degeneration) were pooled (Table 1). Schmorl’s nodes were classified as present or not present and defined as a vertebral endplate irregularity associated with intraspongious disc herniation, irrespective of the size, at either the cranial or caudal endplate, or at both endplates relative to the lumbar disc level. Spondylolisthesis was assessed as either present or not [26 , 27 (link)]. Similarly, vertebral apophyseal injury, defined as any irregularity or signal changes in the apophyseal region, was categorized as either present or not.Table 1

Modified endplate score, based on the original endplate defect score [25 (link)]

Modified endplate defect score	Original endplate defect score
1	Type I—Normal endplate with no interruption
	Type II—Thinning of the endplate, no obvious break
	Type III—Focal endplate defect with established disc marrow contact but with maintained endplate contour
2	Type IV—Endplate defects < 25% of the endplate area
3	Type V—Endplate defects up to 50% of the endplate area
4	Type VI—Extensive damaged endplates up to total destruction

Intra-observer and inter-observer reliability measures were carried out on a set of 15 individuals (5 of the climbers and 10 back pain patients not included in the current study) by the senior radiologist and an additional radiologist (5 years of experience). The latter repeated the evaluation after one month, blinded to previous result.