Abstract
ObjectiveTo compare two different fat-saturated magnetic resonance imaging (MRI) techniques-STIR and T2 SPAIR-in terms of image quality, as well as in terms of their diagnostic performance in detecting sacroiliac joints (SIJ) active inflammation.Materials and MethodsWe included 69 consecutive patients with suspected spondyloarthritis undergoing MRI between 2012 and 2014. The signal-to-noise ratio (SNR) was calculated with the method recommended by the American College of Radiology. Two readers evaluated SIJ MRI following ASAS criteria to assess diagnostic performance regarding the detection of active SIJ inflammation. T1 SPIR Gd+ sequence was used as the reference standard.ResultsThe mean SNR was 72.8 for the T1 SPIR Gd+ sequence, compared with 14.1 and 37.6 for the STIR and T2 SPAIR sequences, respectively. The sensitivity and specificity of STIR and SPAIR T2 sequences did not show any statistically significant differences, for the diagnosis of sacroiliitis with active inflammation.ConclusionOur results corroborate those in the recent literature suggesting that STIR sequences are not superior to T2 SPAIR sequences for SIJ evaluation in patients with suspected spondyloarthritis. On 1.5-T MRI, T2-weighted SPAIR sequences provide better SNRs than do STIR sequences, which reinforces that T2 SPAIR sequences may be an advantageous option for the evaluation of sacroiliitis.
Highlights
Diagnosis is essential for the treatment of axial spondyloarthritis[1], and magnetic resonance imaging (MRI) is the recommended imaging method because it is able to identify findings corresponding to the phase of active inflammation, before the appearance of radiographic findings[1,2]
The comparative evaluation of the mean signal-to-noise ratio (SNR) between the sequences, performed in a paired manner, patient by patient, by the paired t-test, revealed a difference of 58.7 between T1 SPIR Gd+ and short-tau inversion-recovery (STIR), the mean SNR being significantly higher for the T1 SPIR Gd+ sequence (p < 0.000)
In the qualitative evaluation of diagnostic performance, we found no significant difference between the STIR and T2 SPAIR sequences in terms of sensitivity, specificity, accuracy, negative predictive value, or positive predictive value for the diagnosis of active inflammatory sacroiliitis, in accordance with the Assessment of SpondyloArthritis International Society (ASAS) working group diagnostic criteria and using the T1 SPIR Gd+ sequence as the reference
Summary
Diagnosis is essential for the treatment of axial spondyloarthritis[1], and magnetic resonance imaging (MRI) is the recommended imaging method because it is able to identify findings corresponding to the phase of active inflammation, before the appearance of radiographic findings[1,2]. On MRI, active inflammation is characterized by the presence of subchondral bone marrow edema in fluid-sensitive sequences or by contrast enhancement of bone marrow[2]. The Assessment of SpondyloArthritis International Society (ASAS) MRI working group recommended the use of short-tau inversion-recovery (STIR) sequences to identify the bone marrow edema that is indicative of active inflammation of the subchondral tissue[3]. The ASAS MRI working group began to recommend the use of T2-weighted fluid-sensitive sequences, such as STIR sequences, as well as T2-weighted sequences with fat suppression, for that purpose[4]. Sensitivity and specificity measurements were performed for each reader and for each study sequence (STIR and T2 SPAIR) in comparison with the gold standard (T1 SPIR Gd+). Values of p < 0.05 were considered statistically significant
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