Introduction: spinal cord (SC) narrowing is documented in patients with tropical spastic paraparesis/human T cell lymphotropic virus type 1 associated myelopathy (HAM/TSP). It is not consensual that patients without criteria for HAM/TSP present SC lesions. Our hypothesis is that the magnetic resonance images (MRI) could recognize lesions on spinal cord or abnormalities of tractography parameters in patients with lower urinary symptoms (LUTS) without gait impairment, defined as probable HAM/TSP and also called Urinary Dysfunctions Associated to HTLV-1 infection. Objective: investigate the role MRI with tractography in detecting SC abnormalities in HTLV-1 patients presenting lower urinary tract symptoms.

Methods: patients followed in a cohort study were selected and grouped according to Castro-Costa classification: 33 HTLV-1 asymptomatic carries (AC), 31 urinary dysfunction (UD) patients, and 11 seronegative age matched control (SN). They were submitted to 1.5-Tesla-MR scanner (Siemens; Symphony), with two regions of interest (ROI) positioned side by side at T5 and T12-L1. The images were analysed by 2 neuroradiologists that established the measurements of the SC: antero-posterior (AP) and latero-lateral (LL) radius and area and also thoracic and lumbar index :1/(LL x AP diameters). SC were classified as normal or narrowed. Diffusion tensor image (DTI) and fractional anisotropy (FA) were stablished by the manufactory application. LUTS were evaluated by overactive symptoms score (OABSS) and bladder diary.

Results: the majority of patients concluded the MRI exams (99/116). The mean age and standard deviation (SD) was 55.0 (13.6), 56.9 (11.0) and 60.9 (10.3) in SN, AC and UD, respectively. There was no difference between groups regarding age (P = 0.15), sex (0.59), proviral load (P = 0.94), IFN (P = 0.77) and TNF (P = 0.29). SN and AC patients presented higher educational level P = 0.00). The mean (SD) OABSS was 1.05 (0.83) and 7.53 (3.92) in AC and UD, respectively (P<0.01). The median and interquartile range (IQR) of SC thoracic area were 0.40 (0.38 – 0.45), 0.36 (0.33 – 0.40) and 0.33 (0.27 – 0.37) for SN, AC and UD.  The difference was statistically significant in SN versus AC (P = 0.01), SN versus UD (P = 0.00) and AC versus UD (P = 0.03). The median (IQR) of SC lumbar area were 0.67 (0.55 – 0.72), 0.59 (0.54 – 0.67), and 0.53 (0.48 – 0.63) for SN, AC and UD, respectively. Statistically significant difference was observed in SN vs UD and AC versus UD (P = 0.02 and P=0.04, respectively). Median (IQR) fractional anisotropy (FA) values of thoracic field were 0.69 (0.58 – 0.70) in SN, 0.64 (0.55 – 0.71) in AC and 0.57 (0.51 – 0.68) in UD, the difference was not statistically significant difference. Median (IQR) of mean diffusivity (MD) of thoracic field was 1.23 (1.08 – 1.41), 1.26 (1.14 – 1.43) and 1.29 (1.12 – 1.43) in NS, AC and UD, respectively (P>0.05). Median (IQR) of FA values of lumbar field were 0.54 (0.51 – 0.62), 0.50 (0.41 – 0.57) and 0.45 (0.41 – 0.52), with statistically significant difference comparing SN and UD (P = 0.00). Median (IQR) DM values in lumbar field were 1.12 (0.92 – 1.35), 0.97 (0.88 – 1.16) and 0.97 (0.88 – 1.20) in SN, AC and UD, respectively, with no statistically significant difference. Conclusion: Patients with urinary disfunction (UD) exhibited lesser values of SC measurements. SC area seems to be more the most reliable parameter in explaining LUTS in HTLV-1 infected patients. We found no difference regarding diffusion tensor image parameters such as FA and MD.

Spinal cord tractography may be useful in explaining urinary dysfunctions (overactive or underactive bladder symptoms) in patients infected by human T cell lymphotropic virus type 1 (HTLV-1). This is the first study to evaluate patients presenting only urinary dysfunctions. Idiopathic overactive bladder can be better understood using tractographic parameters.

Conclusion: Patients with urinary disfunction (UD) exhibited lesser values of SC measurements. SC area seems to be more the most reliable parameter in explaining LUTS in HTLV-1 infected patients. We found no difference regarding diffusion tensor image parameters such as FA and MD.

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Continence 7S1 (2023) 100972
DOI: 10.1016/j.cont.2023.100972