In 3 patients,
it was not possible to localize normal and abnormal patterns using SWE due to a technical problem during the export of the data.
The analysis was performed from the remaining 18 patients (mean age 65 ± 6 years,
min 54 – max 79).
The PSA values were 6.9 ± 2.2 ng/mL.
Eight patients exhibited significant prostate adenocarcinomas.
Among the 26 nodules detected either at US or at pathology,
10 were adenocarcinomas with Gleason score above 6 and 16 were adenomatous hyperplasia or focal prostatitis.
The correlation between B-mode + pathology and CDUS,
CEUS or MRI could not be obtained for 3 / 3 / 4 nodules,
respectively.
SWE was feasible in all patients.
Signals were obtained in both the peripheral and the transition zones with good correlation to anatomical areas.
Because of higher attenuation,
the deepest transition zone was not correctly assessed over 4-5 cm.
Macro-calcifications exhibited very high stiffness values.
Transition zone appeared heterogeneous with stiffness values above 40 kPa.
SWE signals were adequate for all peripheral nodules.
Limitations resulted from gas interposition and higher pressure of the end-fire transducer on the rectal wall and the adjacent posterior gland.
Prostate cancer nodules exhibited a high stiffness (mean 55 ± 45 kPa,
min 23/ max 180 kPa) than the adjacent peripheral gland (mean 18 ± 9 kPa).
Peripheral adenomatous hyperplasia and focal prostatitis exhibited a significantly lower stiffness (mean 19 ± 5 kPa,
min 12/ max 28 kPa; p< 0.01).
The stiffness ratio between nodule and adjacent parenchyma was significantly higher for cancer (3.0 ± 1.0) compared to benign nodules (1.0 ± 0.20; p< 0.01).
The cut-off value of 1.5 allowed the best discrimination of the two populations.
The sensitivity (Se),
specificity (Spe),
Positive predictive value (PPV) and Negative predictive value (NPV) were calculated for each modality: CDUS,
CEUS,
SWE and MRI.
CDUS: Se= 50%; Spe= 73%; PPV= 50%; NPV= 73%
CEUS: Se= 67%; Spe= 86%; PPV= 75%; NPV= 80%
SWE: Se= 90%; Spe= 100%; PPV= 100%; NPV= 94%
MRI: Se= 62%; Spe= 78%; PPV= 62%; NPV= 78%