Utility of ultrasound and MRI in prenatal diagnosis of placenta accreta: a pilot study.

OBJECTIVE: The purpose of this study was to evaluate transabdominal pelvic ultrasound and MRI for the prenatal diagnosis of placenta accreta. MATERIALS AND METHODS: A historical cohort pilot study was performed at our institution to identify women at risk of placenta accreta who had undergone both prenatal ultrasound and MRI. Findings at ultrasound and MRI were compared with the final diagnosis, which was established with clinical findings at delivery and pathologic examination of specimens. Volume measurements were made of low-signal-intensity intraplacental bands on T2-weighted MR images. Risk factors for placental insufficiency were recorded. RESULTS: Thirteen patients at risk of placenta accreta underwent both sonography and MRI. Nine of these patients had abnormal placentation. With ultrasound, abnormal placentation was correctly identified in six of nine patients (67%) and the absence of accreta in two of four patients (50%). With MRI, abnormal placentation was correctly identified in seven of nine patients (78%) and the absence of accreta in three of four patients (75%). The volumes of low-signal-intensity bands were significantly different in the patients with abnormal placentation and those without placenta accreta (p = 0.047), and band volumes were significantly different among patients with accreta, increta, and percreta (p < 0.0005). CONCLUSION: The accuracy of MRI may improve if volumes of low-signal-intensity bands are calculated, MRI is performed before 30 weeks' gestation, and risk factors for placental insufficiency are recognized.

Canine prostate: contrast-enhanced US-guided radiofrequency ablation with urethral and neurovascular cooling--initial experience.

PURPOSE: To prospectively evaluate in a canine model contrast material-enhanced ultrasonography (US) for guiding and monitoring radiofrequency (RF) ablation of the entire prostate, with urethral and vascular cooling to protect the surrounding structures. MATERIALS AND METHODS: After approval by the institutional animal use and care committee, an RF electrode was used to ablate the entire prostate in 15 dogs. During ablation, pulse-inversion harmonic US was performed by using an endocavitary probe after an intravenous bolus injection (0.04 mL/kg) and infusion (0.015 muL/kg/min) of a US contrast agent. In group 1 (n = 4), no cooling protection was used during ablation. In group 2 (n = 5), urethral and bladder protection was provided by inserting a 12-F catheter infused with cold saline (8 degrees C +/- 4 [standard deviation]) at a rate of 100 mL/min. In group 3 (n = 6), further protection of the neurovascular bundles (NVBs) was provided by infusing cold saline (8 degrees C +/- 4) into the iliac arteries at a rate of 50 mL/min by means of catheterization of the femoral artery. Pathologic findings among the three groups were compared by using the Wilcoxon rank sum test. RESULTS: The average volumes of prostate ablation achieved in the three groups were 96.6%, 91.9%, and 92%. Contrast-enhanced pulse-inversion harmonic US allowed visualization and monitoring of urethral and NVB blood flow during the ablation. Without protection, damage to the urethra and the NVB was demonstrated at both US and pathologic examination. There was highly significant difference in urethral damage between groups with and the group without urethral cooling (P = .002), while intraarterial cooling demonstrated a nonsignificant trend toward a decreased NVB damage (P = .069). CONCLUSION: Contrast-enhanced US can guide RF ablation of the entire prostate. Infusion of cold saline provides effective protection for the urethra during such procedures. The application of intraarterial cooling did not provide a significant improvement in the protection of the NVB in this small study.

Quantitative computed tomography perfusion of prostate cancer: correlation with whole-mount pathology.

PURPOSE: Microvessel density within the prostate is associated with presence of cancer, disease stage, and disease-specific survival. We evaluated multidetector computed tomography (CT) to estimate prostate perfusion and localize prostate cancer. PATIENTS AND METHODS: Ten subjects were evaluated with contrast enhanced CT before radical prostatectomy with the Mx8000IDT 16-slice scanner. Following baseline pelvic scan, 100 cc of Optiray 300 was administered intravenously (4 cc per second). Repeated dynamic scans through the prostate were obtained at 20, 30, 40, 50, and 60 seconds following initiation of contrast injection. Computed tomography perfusion was compared with pathologic findings of Gleason score and tumor volume on whole-mount prostatectomy specimens. RESULTS: Conventional adenocarcinoma (Gleason score, 6-10) was present in all subjects, including one who also demonstrated a mucinous variant of prostate cancer. Visible focal CT enhancement was noted in 1 patient with a high-volume tumor and a Gleason score of 10. A positive correlation between local estimates of CT perfusion and percent of prostate volume occupied by tumor in each sextant was found for half of the subjects (Pearson correlation coefficient, 0.3-0.95; mean, 0.48) but statistically significant correlation (P < 0.05; Pearson coefficient, 0.9-0.95) was present in only the 2 subjects with the highest Gleason scores (8 and 10) and the highest tumor volume (> or = 50% in > or = 1 sextant region). CONCLUSION: Visible enhancement of prostate cancer during dynamic CT is present in a minority of subjects. Correlation between quantitative CT perfusion and tumor location is statistically significant only in subjects with localized high-volume, poorly differentiated prostate cancer.

Vascular endothelial growth factor (VEGF) expression in locally advanced prostate cancer: secondary analysis of radiation therapy oncology group (RTOG) 8610.

BACKGROUND: Angiogenesis is a key element in solid-tumor growth, invasion, and metastasis. VEGF is among the most potent angiogenic factor thus far detected. The aim of the present study is to explore the potential of VEGF (also known as VEGF-A) as a prognostic and predictive biomarker among men with locally advanced prostate cancer. METHODS: The analysis was performed using patients enrolled on RTOG 8610, a phase III randomized control trial of radiation therapy alone (Arm 1) versus short-term neoadjuvant and concurrent androgen deprivation and radiation therapy (Arm 2) in men with locally advanced prostate carcinoma. Tissue samples were obtained from the RTOG tissue repository. Hematoxylin and eosin slides were reviewed, and paraffin blocks were immunohistochemically stained for VEGF expression and graded by Intensity score (0-3). Cox or Fine and Gray's proportional hazards models were used. RESULTS: Sufficient pathologic material was available from 103 (23%) of the 456 analyzable patients enrolled in the RTOG 8610 study. There were no statistically significant differences in the pre-treatment characteristics between the patient groups with and without VEGF intensity data. Median follow-up for all surviving patients with VEGF intensity data is 12.2 years. Univariate and multivariate analyses demonstrated no statistically significant correlation between the intensity of VEGF expression and overall survival, distant metastasis, local progression, disease-free survival, or biochemical failure. VEGF expression was also not statistically significantly associated with any of the endpoints when analyzed by treatment arm. CONCLUSIONS: This study revealed no statistically significant prognostic or predictive value of VEGF expression for locally advanced prostate cancer. This analysis is among one of the largest sample bases with long-term follow-up in a well-characterized patient population. There is an urgent need to establish multidisciplinary initiatives for coordinating further research in the area of human prostate cancer biomarkers.

Contrast enhanced ultrasound for radio frequency ablation of canine prostates: initial results.

PURPOSE: We determined the feasibility of contrast enhanced ultrasound for radio frequency ablation of the entire prostate as a method of minimally invasive treatment for prostate cancer in a canine model. MATERIALS AND METHODS: Approval of the Institutional Animal Use and Care committee was obtained. Initially 5 dogs (group 1) were tested using variable power (5 to 30 W), time (4 to 12 minutes), bolus (0.01 to 0.04 ml/kg) and infusion (3 to 11 ml per minute at 0.015 microl/kg) injections of an ultrasound contrast agent with conventional grayscale power Doppler and pulse inversion harmonic imaging to establish optimal parameters. Subsequently 4 dogs (group 2) underwent entire prostate ablation using parameters based on group 1. The size of the thermal lesions and residual viable tissue was measured with ImageJ software (National Institutes of Health, Bethesda, Maryland) on ultrasound and pathological study. Linear regression and Student's t test were used for statistical analysis. RESULTS: A bolus of 0.04 ml/kg, an infusion of 11 ml per minute at 0.015 microl/kg and the contrast enhanced pulse inversion harmonic imaging mode were ranked best for guiding ablation. Thermal lesion volume was proportional to ablation power and time. There was no significant difference in measured thermal lesion size in group 1 between ultrasound and pathological findings (mean +/- SD 1.51 +/- 0.74 and 1.46 +/- 0.74 cm3, p = 0.56) or in residual viable tissue in group 2 (0.43 +/- 0.043 and 0.41 +/- 0.291 cm3, p = 0.21). The average volume of prostate ablation achieved in group 2 was 96.3%. CONCLUSIONS: Contrast enhanced pulse inversion harmonic imaging is able to guide, monitor and control radio frequency ablation of the entire prostate.