MRI-CORRELATED MORPHOLOGICAL-CHANGES AFTER ND-YAG LASER TREATMENT OF THE HUMAN PROSTATE WITH THE SIDEFOCUS(R) FIBER

Optimal treatment parameters and appropriate methods of examination fo r Nd:YAG laser coagulation of the human prostate in dependence of powe r-setting and time using the SideFocus(R) side-firing delivery system have been determined. Transurethral free-beam laser coagulation was pe rformed in 10 patients prior to planned radical prostatectomy or cysto prostatectomy. Thereof, 6 patients underwent transperitoneal laparosco pic lymphadenectomy and laser coagulation of the prostate between 4 an d 9 days prior to open surgery. These same patients had undergone MRI examination with an endorectal coil during staging and prior to radica l prostatectomy. Depth and volume of coagulated prostatic tissue of a 4-quadrant laser application were measured at power-settings of 40 W/9 0 s and 60 W/60 s. There was no difference in volume coagulation betwe en the two treatment modalities. In contrast there was a significant d ifference in volume coagulation between those prostates removed at 4-9 days and those removed at 60-210 min after laser coagulation. In hist ological and MRI examination, however, there was a strong correlation with view to coagulation volume in histological and MRI examination. U sing the SideFocus(R) side-firing laser fiber, both treatment modaliti es showed comparable volume coagulation. Laser-induced changes are con clusively discernible by 4 days, MRI examination with an endorectal co il thus being perfectly suitable for assessment.