Key points
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Urethral sphincter complex DTI is feasible at 3 T for prostate cancer patients.
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Subject motion and eddy currents corrections did not significantly influenced DTI metrics.
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DTI derived metrics differentiate the structures of the patients’ urethral sphincter complex.
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Study findings are a start point to predict post-surgical continence recovery rate.
Introduction
Materials and methods
Patient population
Variable name | Median | IQR [min-max] (N) |
---|---|---|
Patient age (years old) | 64.5 | 7 [48–72] (28) |
BMI (kg/m2) | 27.1 | 3.57 [21.7–33.2] (28) |
Preoperative PSA (ng/mL) | 7.0 | 4.55 [2.0–15.1] (24) |
PV (cm3) | 43 | 20 [25–76] (28) |
Data acquisition
Data processing and fiber tractography
Quantitative analysis
Results
Optimization of acquisition and fiber tracking parameters
Case | b Value (s/mm | Number of directions | Number of slices | In-plane resolution (mm2) | Sequence duration |
---|---|---|---|---|---|
001’ | 800 | 32 | 25 | 1.56 × 1.56 | 7 min 46 s |
002’ | 800 | 32 | 20 | 1.56 × 1.56 | 6 min 26 s |
001 | 600 | 15 | 40 | 1.39 × 1.39 | 4 min 9 s |
Effect of patient motion and eddy currents corrections
Structures architecture depicted with fiber tractography
Quantitative analysis on DTI metrics
Proximal sphincter | Distal sphincter | Membranous urethra | p value | |
---|---|---|---|---|
FA | 0.37; 0.04 [0.31–0.46] | 0.32; 0.04 [0.25–0.37] | 0.33; 0.06 [0.22–0.49] | 4.94e-6 * |
AD | 2.07; 0.18 [ 1.89–2.56] | 2.08; 0.20 [1.90–2.75] | 1.89; 0.22 [1.58–2.70] | 6.18e-5 * |
MD | 1.51; 0.16 [1.37–1.91] | 1.58; 0.19 [1.39–2.06] | 1.41; 0.16 [1.17–1.99] | 4.70e-5 * |
RD | 1.23; 0.15 [1.08–1.58] | 1.30; 0.18 [1.13–1.71] | 1.23; 0.19 [0.99–2.47] | 1.12e-2 * |
Tract density | 1.07; 0.96 [0.23–2.62] | 0.28; 0.21 [0.03–0.69] | 5.57; 7.61 [0.35–52.90] | 9.23e-13 * |
Tract | 78.6; 17.16 [5.93–118..94] | 55.52; 6.55 [28.71–65.88] | 26.10; 7.71 [9.82–34.8] | 1.44e-15* |
Structure pairs | FA | AD | MD | RD | Tract density | Tract length |
---|---|---|---|---|---|---|
PROX-DIST | 4.06e-6* | 9.91e-1* | 5.80e-2* | 1.21e-2* | 7.16e-6* | 1.18e-4* |
PROX−MU | 1.35e-3 | 2.11e-4* | 1.60e-2* | 4.80e-l* | 5.12e-3* | 4.32e-16* |
DIST-MU | 1.31e-1* | 2.11e-4* | 2.60e-5* | 4.51e-2* | 4.97e-13* | 1.55e-5* |