Denis Lyonnet

Transrectal High Intensity Focused Ultrasound for the Treatment of Localized Prostate Cancer: Factors Influencing the Outcome

Objectives: Efficacy evaluation of high intensity focused ultrasound (HIFU) treatment for localized prostate cancer and identification of the factors affecting the outcome. Patients and Methods: 102 patients with prostate cancer stage T1–T2 and noncandidates for radical prostatectomy have been treated with HIFU (Ablatherm™, EDAP–Technomed). The disease progression (failure) was strictly defined by any positive sample at control biopsies, whatever the prostate–specific antigen (PSA) level, or by 3 consecutive increases in PSA levels in case of negative biopsies. Results: At inclusion, patients’ baseline characteristics were (mean ± standard deviation): age 70.8 (±6.13) years, PSA 8.38 (±4.8) ng/ml, prostate volume 33.3 (±16.71) cm3. The population mean follow–up was 19 months (3–76 months). The overall success rate was 66%. Statistically significant variations of the overall success with a more favorable outcome were observed when (1) the initial PSA level was ≤10 ng/ml (73 vs. 50%, p = 0.02), (2) the Gleason score was ≤6 (81 vs. 46%, p<0.001) and (3) the pretreatment sextant biopsy evidenced 1–4 positive samples (68 vs. 40%, p = 0.01). Conclusion: Results observed after HIFU treatment in localized prostate cancer are now challenging those obtained after radiation therapy. The success rate is influenced by disease–related prognostic factors.

MRI Appearance of Prostate following Transrectal HIFU Ablation of Localized Cancer

Objectives: To evaluate the accuracy of gadolinium–enhanced MRI in gauging the extent of the tissue damage induced by transrectal high intensity focused ultrasound (HIFU) therapy and to assess how well the results obtained with this modality correlate with histological findings (control biopsies). Methods: Twenty–one patients with biopsy–proven prostate cancer (T1–T2–T3a, Nx, M0) who gave informed consent were included in the protocol. They underwent pre– and postoperative (2–5 days after HIFU treatment) MR examinations. Fifteen patients also underwent a follow–up MR examination 1–5 months postoperatively. MR findings were compared with the results of postoperative transrectal biopsy examinations. Results: The prostate volume increased after the HIFU session from 43.9±18.6 to 52.1±21 cm3 by day 2 (p<0.001). On fat–saturated gadolinium–enhanced T1–weighted images, the treated area appeared as a hypointense zone surrounded by a peripheral rim of enhancement in all patients. A positive correlation (r = 0.75) was found between the volume of the hypointense zone measured at days 2–5 (30±11 cm3, 67% of the posttreatment prostate volume) and the theoretical target volume (22±5 cm3, 61% of the initial prostate volume). MRI showed that the anterior part of the base was not reached by the ultrasound beam. The mean volume of the untreated zone (prostate without any MRI modifications) was 8 cm3 (range, 0.4–36). No correlation was found between the MRI appearance of the treated area and the intensity of the necrosis or the presence of foci of residual, viable cancer. Conclusion: Gadolinium–enhanced MRI is an accurate way of determining the extent of tissue damage induced in HIFU ablative therapy, but cannot predict histological results.

Evaluation of T2-weighted and dynamic contrast-enhanced MRI in localizing prostate cancer before repeat biopsy

We assessed the accuracy of T2-weighted (T2w) and dynamic contrast-enhanced (DCE) 1.5-T magnetic resonance imaging (MRI) in localizing prostate cancer before transrectal ultrasound-guided repeat biopsy. Ninety-three patients with abnormal PSA level and negative prostate biopsy underwent T2w and DCE prostate MRI using pelvic coil before repeat biopsy. T2w and DCE images were interpreted using visual criteria only. MR results were correlated with repeat biopsy findings in ten prostate sectors. Repeat biopsy found prostate cancer in 23 patients (24.7%) and 44 sectors (6.6%). At per patient analysis, the sensitivity, specificity, positive and negative predictive values were 47.8%, 44.3%, 20.4% and 79.5% for T2w imaging and 82.6%, 20%, 24.4% and 93.3% for DCE imaging. When all suspicious areas (on T2w or DCE imaging) were taken into account, a sensitivity of 82.6% and a negative predictive value of 100% could be achieved. At per sector analysis, DCE imaging was significantly less specific (83.5% vs. 89.7%, p < 0.002) than T2w imaging; it was more sensitive (52.4% vs. 32.1%), but the difference was hardly significant (p = 0.09). T2w and DCE MRI using pelvic coil and visual diagnostic criteria can guide prostate repeat biopsy, with a good sensitivity and NPV.

Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI

The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies (“routine biopsies”); operator 2 obtained up to three cores per suspicious lesion on MRI (“targeted biopsies”). Seventy-seven suspicious lesions were detected on DCE images (n = 52), T2w images (n = 2) or both (n = 23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p = 0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p < 0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05–3.64) and 1.38 (95% CI 1.13–1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue.

Imaging of prostate cancer local recurrences: why and how?

ObjectiveBecause prostate cancer local recurrences can be efficiently treated by salvage therapies, it becomes critical to detect them early.MethodsThe first alert is the rise of the prostate specific antigen (PSA) level after the post-treatment nadir, which can correspond to a distant recurrence, a local recurrence or both. This so-called biochemical failure (BF) is defined as PSA level > 0.2 ng/ml after radical prostatectomy (RP) and PSA level > nadir + 2 ng/ml after radiotherapy. There is no consensual definition of BF after cryotherapy, high-intensity focused ultrasound (HIFU) ablation or brachytherapy.ResultsLocal recurrences after RP are treated by radiotherapy, those after radiotherapy by RP, cryotherapy, brachytherapy or HIFU ablation. Recurrences after cryotherapy or HIFU ablation can be treated by a second session or radiotherapy. Recurrences after brachytherapy are difficult to treat. In patients with BF, MRI can detect local recurrences, whatever the initial treatment was. Dynamic contrast-enhanced MRI seems particularly accurate. The role of spectroscopy remains controversial. Ultrasound-based techniques are less accurate, but this may change with the advent of ultrasonic contrast media.ConclusionThese recent advances in imaging may improve the outcome of salvage therapies (by improving patient selection and treatment targeting) and should open the way to focal salvage treatments in the near future.

Severe bleeding after nephrolithotomy : Results of hyperselective embolization

From 1984 to 1998, 808 patients underwent percutaneous nephrolithotomy for removal of renal calculi. Although the technique is safe and effective, complications, including hemorrhages, have been reported. Eight patients (1%) are described in whom severe bleeding following percutaneous nephrolithotomy was uncontrolled by usual methods and treated by hyperselective embolization. Renal arteriography has shown arteriovenous fistula in 3 patients, pseudo aneurysm in 4 and both in1 patient. Embolization allowed definitive treatment of these lesions in 7 of our 8 patients. The failure of embolization in 1 patient imposed a partial nephrectomy. Patients with normal renal function did not suffer significant change in the serum creatinine after treatment (percutaneous nephrolithotomy + embolization), and all but 1 patient have maintained normal blood pressure. In the authors’ opinion, hyperselective embolization is the least invasive and best treatment for massive hemorrhage after percutaneous nephrolithotomy.

Acute thrombosis of renal transplant artery: graft salvage by means of intra-arterial fibrinolysis.

BACKGROUND Arterial thrombosis in a transplanted kidney is a serious complication that usually leads to graft loss. The purpose of our study was to evaluate intra-arterial fibrinolysis as a treatment of acute renal transplant artery thrombosis and to determine the maximum period of occlusion allowing a reasonable chance of graft salvage. METHODS AND RESULTS Four patients underwent intra-arterial fibrinolysis for acute transplant artery thrombosis. Transplantations had been performed 29 days to 10 years before the fibrinolysis. Fibrinolysis was carried out by using recombitant tissue plasminogen activator (n=1) or urokinase (n=3). In one patient, anuric for 13 hr at admittance, fibrinolysis could not revascularize the graft artery. In a second patient, anuric for 48 hr at admittance, fibrinolysis did revascularize the graft artery, but dialysis could not be discontinued. In the two remaining patients, anuric for 19 and 20 hr at admittance, the graft artery was successfully revascularized and dialysis could be discontinued 1 week later. One of these two patients returned to dialysis 71 months later because of chronic rejection. Thirty-four months after the acute episode, the remaining patient had a patent artery and did not require dialysis. CONCLUSIONS Fibrinolysis seems an efficient treatment that may save transplants after up to 24 hr of the arterial occlusion.

Transient MR elastography (t-MRE) using ultrasound radiation force: Theory, safety, and initial experiments in vitro

The purpose of our study was to assess the feasibility of using ultrasound radiation force as a safe vibration source for transient MR elastography (t‐MRE). We present a theoretical framework to predict the phase shift of the complex MRE signal, the temperature elevation due to ultrasound, and safety indicators (ISPPA, ISPTA, MI). Next, we report wave images acquired in porcine liver samples in vitro. MR thermometry was used to estimate the temperature elevation induced by ultrasound. Finally, we discuss the implications of our results with regard to the feasibility of using radiation force for t‐MRE in a clinical setting, and a specific echo‐planar imaging (EPI) MRE sequence is proposed. Magn Reson Med 60:871–881, 2008.

Tubular ectasia of the rete testis: a potential pitfall in scrotal imaging

Abstract. Tubular ectasia of the rete testis (TERT) is a benign entity due to dilation of the tubules of the rete testis. Most of the time it is discovered incidentally on scrotal sonograms and may be misinterpreted as malignant. This article outlines the diagnostic criteria of TERT, its possible causes, its incidence and its potential evolution. Recognizing this entity owing to its characteristic clinical, sonographic and, if necessary, MRI features is important to avoid unnecessary surgery or biopsies.

Nonmetastatic renal-cell carcinoma: is it really possible to define rational guidelines for post-treatment follow-up?

Defining rational follow-up guidelines in patients treated for cancer is important, from both a medical and an economical perspective. Renal-cell carcinoma is reputed to be unpredictable in its course and only a few, and often contradictory, follow-up guidelines exist for patients treated for nonmetastatic renal-cell carcinoma. Recent advances in tumor biology have contributed to a better understanding of this cancer and have indicated that personalized follow-up regimens, based on tumor and host molecular characteristics, might be possible in the near future.