The diagnostic accuracy for detecting small low-grade malignant lesions
in the prostate is strongly dependent on MRI protocol, MRI quality and user experience.15 16 There are many studies in which MRI is compared with RP specimens.17–21 However, limitations in validating the MRI findings with the http://www.selleckchem.com/products/carfilzomib-pr-171.html ‘gold standard’ whole mount histopathology arose from free hand slicing (deformation) and non-uniform distortion on fixation of the specimens. The orientation of the cutting planes in the prostatectomy specimen can be different from the scanning planes of mpMRI, and it is therefore challenging to assess the true accuracy of MRI. However, Turkbey et al provided a solution for this issue in 2010 by processing the histopathological specimens exactly according to the MRI by using a customised three-dimensional (3D) mold to slice up the RP specimen from 45 patients. The positive predictive value of 3 T mpMRI for the detection of prostate cancer increased to 98%, 98% and 100% in the overall prostate, peripheral zone and central gland, respectively.22 Contrast-enhanced ultrasound The patients who participate in the AMC Amsterdam will undergo a CEUS pre-IRE and pre-RP to determine the completeness of the ablation zone detection by this imaging technique. CEUS involves the use of microbubble contrast agents and specialised imaging techniques to show sensitive blood flow and tissue perfusion information.
CEUS is safe with no requirement for ionising radiation and no risk for nephrotoxicity and can be easily performed. Ultrasound contrast agents consist of a solution of gas-filled
shell-stabilised microbubbles with a diameter in the order of micrometres. These bubbles stay inside the blood pool and travel through all blood vessels, including the microvasculature.23 Two studies have been performed with CEUS in IRE ablated lesions. In one study, CEUS was performed in patients with unresectable malignant hepatic tumours. In the second study, CEUS was performed following IRE in chemotherapy-refractory liver metastases in patients who were no candidates for surgery Batimastat or radiofrequency ablation. The CEUS data showed a clearly confined devascularised lesion, corresponding to the ablated area.24 25 Clinical pathway Patients will be admitted 1 day before the scheduled IRE procedure. The transperineal ultrasound-guided insertion of the IRE needles and the electroporation will be performed under general anaesthesia and muscle relaxants. Full paralysis during electroporation is needed to prevent patient motion due to the high-voltage pulses. The specified target area is ablated. All patients will be given a Foley catheter before the procedure as well as prophylactic antibiotics. The day following the procedure, the Foley catheter will be removed and the patient will leave the hospital after successful voiding.