Tunica albuginea acellular matrix graft for penile reconstruction in the rabbit: a model for treating Peyronie's disease.

OBJECTIVE: To evaluate the use of an acellular matrix graft of the tunica albuginea for functional penile reconstruction in severe cases of Peyronie's disease. MATERIALS AND METHODS: In 18 rabbits, an acellular matrix graft of the tunica albuginea was used to cover a 4 x 8 mm tunical defect, and six animals each were killed 1, 3 and 6 months later; four unoperated animals served as histological controls. Before death an erection was induced by papaverine, with the quality classified on a scale of 0-5, and cavernosography performed. After death the penis was prepared for histological study, and the cell number, collagen and elastic fibre content evaluated in the regenerated matrix, and in control specimens and four unimplanted matrices. RESULTS: Of 18 experimental animals, 11 had normal erections before death, four had slight penile deviation and three developed no erection. Failure was caused by severe postoperative haematoma, resulting in scar tissue. There was no graft rejection. Histologically there was no difference between natural and regenerated tunica. The collagen content and cell number were not significantly different in regenerated and control samples. There were significantly fewer elastic fibres in the unimplanted grafts and the 1-month group, but in later samples this difference was no longer evident. CONCLUSION: The homologous acellular matrix graft of the tunica albuginea warrants further evaluation as an alternative treatment in Peyronie's disease, despite some postoperative failures. The advantage of this orthotopic biomaterial is its rapid integration, with no rejection.

Advances in uroradiological imaging.

The development of new imaging techniques and the refinement of established methods in uroradiological imaging is proceeding rapidly. In the last few years several important developments have been implemented in the routine diagnostic evaluation of urological patients.A milestone is the recent advent of multidetector helical computed tomography (CT), enabling the radiologist to provide the clinician with high-quality three-dimensional (3-D) reconstructions of the urological organs. Powerful workstations are an indispensable tool in the post-processing of CT and magnetic resonance imaging (MRI)data. Significant advances in imaging were obtained in the fields of oncological imaging (e.g. prostate MRI and spectroscopic imaging), paediatric uroradiology(e.g. MR urography) and the evaluation of stone disease by unenhanced helical CT.

Time dependent smooth muscle regeneration and maturation in a bladder acellular matrix graft: histological studies and in vivo functional evaluation.

PURPOSE: We evaluated the time dependence of smooth muscle regeneration and restoration of in vivo functional properties in bladder augmented with a bladder acellular matrix graft. MATERIALS AND METHODS: A total of 45 Sprague-Dawley rats underwent augmentation cystoplasty with a bladder acellular matrix graft. Two rats each were sacrificed at various intervals within the first 21 days and 6 each were sacrificed at 4, 8 and 12 weeks. This second group underwent preoperative and postoperative assessment of bladder function, including cystometry, electrostimulation and stimulation with ice water, potassium and carbachol, as well as labeling of the bladder wall by the injection of fluorescent microspheres. After sacrifice slides of the bladders prepared for hematoxylin and eosin, trichrome, KI67, vimentin, desmin, smooth muscle specific alpha-actin and fluorescent microspheres were evaluated. RESULTS: Within 2 weeks the number of cells in the matrix as well as the proliferation index increased rapidly and then decreased gradually. Erythrocytes and inflammatory cells were found in the matrix within 2 to 4 days, followed by fibroblasts. A bladder host-to-matrix shift was evident by the appearance of microspheres in the matrix. Cell marker expression indicated the early appearance of vimentin and alpha-actin within the first 10 days. Distinct desmin expression was observed later, when the first smooth muscle cells were recognized. Functional evaluation revealed restored bladder function at 12 weeks. CONCLUSIONS: The time dependent increase of muscle cell markers during smooth muscle cell regeneration in a bladder acellular matrix graft is concordant with the progressive restoration of bladder function. These results may support the bladder acellular matrix graft concept for clinical application.

Brachytherapy for prostate cancer: endorectal MR imaging of local treatment-related changes.

PURPOSE: To determine the local treatment-related endorectal magnetic resonance (MR) imaging findings after brachytherapy for prostate cancer. MATERIALS AND METHODS: Endorectal MR imaging was performed in 35 consecutive patients at a mean interval of 12 months (range, 1-31 months) after brachytherapy for prostate cancer. Transverse T1-weighted and high-spatial-resolution transverse and coronal T2-weighted images were acquired. Two readers reviewed MR image quality and findings, with discrepancies resolved by consensus. Posttreatment urinary symptoms in patients (n = 24) were documented by using chart review. RESULTS: All studies were of diagnostic quality. On T2-weighted images, prostatic findings consisted of diffuse low signal intensity (n = 35) and indistinct zonal anatomy (n = 34). Intra- and extraprostatic seed locations could be distinguished. The most common extraprostatic site of seed implantation was the neurovascular bundles (n = 35, bilateral in 32). The most common extraprostatic tissue finding was increased signal intensity on T2-weighted images in the levator ani muscle (n = 34) and the genitourinary diaphragm (n = 28). Postbrachytherapy urinary symptoms showed no demonstrable correlation with periurethral or genitourinary diaphragm seed implantation or with signal intensity change in the genitourinary diaphragm. CONCLUSION: Endorectal MR imaging can be used to evaluate seed distribution and to demonstrate treatment-related changes after brachytherapy for prostate cancer.

Sextant localization of prostate cancer: comparison of sextant biopsy, magnetic resonance imaging and magnetic resonance spectroscopic imaging with step section histology.

PURPOSE: We compared the accuracy of endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging with that of sextant biopsy for the sextant localization of prostate cancer. MATERIALS AND METHODS: Sextant biopsy, MRI, magnetic resonance spectroscopic imaging and radical prostatectomy with step section histology were done in 47 patients with prostate cancer. For each sextant we categorized biopsy and imaging results as positive or negative for cancer. Step section histology was used as the standard of reference. RESULTS: For sextant localization of prostate cancer MRI and magnetic resonance spectroscopic imaging were more sensitive but less specific than biopsy (67% and 76% versus 50%, and 69% and 68% versus 82%, respectively). The sensitivity of sextant biopsy was significantly less in the prostate apex than in the mid prostate or prostate base (38% versus 52% and 62%, respectively). MRI and magnetic resonance spectroscopic imaging had similar efficacy throughout the prostate compared with biopsy only as well as better sensitivity and specificity in the prostate apex (60% and 75%, and 86% and 68%, respectively). A positive biopsy or imaging result had 94% sensitivity for cancer and concordant positivity by all 3 tests was highly specific at 98%. CONCLUSIONS: Overall MRI and magnetic resonance spectroscopic imaging have accuracy similar to biopsy for intraprostatic localization of cancer and they are more accurate than biopsy in the prostate apex. These 2 imaging modalities may supplement biopsy results by increasing physician confidence when evaluating intraprostatic tumor location, which may be important for planning disease targeted therapy.

Imaging for recurrent prostate cancer.

Multiple imaging modalities are available to evaluate recurrent prostate cancer following primary treatment with RP, RT, or cryo-surgery. These tests must be used in close conjunction with clinical parameters, such as the characteristics of the tumor itself (grade, stage) as well as specific PSA characteristics that can help predict the sites of probable recurrence. Figure 19 represents an algorithm of how patients can be monitored for recurrence according to their mode of primary treatment. As more treatments become available for recurrent prostate cancer, it will be necessary to monitor disease response with many of the imaging modalities discussed in this article.