RESUMO
OBJECTIVE: To assess the prostate cancer (CaP) detection rates of contrast-enhanced, transrectal subharmonic ultrasound imaging (SHI). MATERIALS AND METHODS: This IRB-approved study enrolled 55 subjects. The initial 5 subjects were studied for SHI optimization, while the remaining 50 were evaluated with contrast-enhanced sonography using continuous SHI, color, and power Doppler as well as conventional grayscale, continuous color, and power Doppler and SHI combined with maximum flash replenishment. A maximum of 6 directed biopsy cores were obtained from sites of greatest asymmetrical enhancement, followed by spatially distributed cores in a double sextant distribution. Subharmonic time-intensity parameters, including time to peak intensity, peak intensity, and estimated perfusion were also evaluated for each directed biopsy core. Receiver operating characteristic curve analysis and conditional logistic regression were employed to assess the benefit of each modality and the quantitative SHI parameters. RESULTS: Cancer was detected in 22 of 50 subjects. Among subjects with clinically significant CaP (n = 11), targeted cores were more likely to be positive (odds ratio 1.39, P = .02). The majority of patients detected by SHI demonstrated significant CaP (5/8); SHI remained an independent marker of malignancy in a multivariate logistic regression model (P = .027). Receiver operating characteristic curve analysis of imaging findings compared to biopsy results yielded diagnostic accuracies ranging from 0.59 to 0.80 for all imaging modalities with the highest being for quantitative subharmonic perfusion estimates. CONCLUSION: This first-in-humans study provides a preliminary estimate of the diagnostic accuracy of SHI for detection of clinically significant CaP (up to 80%).
Assuntos
Próstata/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico , Ultrassonografia Doppler/métodos , Idoso , Biópsia com Agulha de Grande Calibre/estatística & dados numéricos , Meios de Contraste/administração & dosagem , Humanos , Masculino , Microbolhas , Pessoa de Meia-Idade , Estudos Prospectivos , Próstata/patologia , Neoplasias da Próstata/epidemiologia , Neoplasias da Próstata/patologia , Curva ROC , Ultrassonografia Doppler/estatística & dados numéricosRESUMO
During the past 25 years, many attempts have been made to establish effective ultrasound contrast agents for both cardiac and noncardiac applications. The ideal ultrasound contrast agent would be: (a) nontoxic; (b) injectable intravenously; (c) capable of passing through the pulmonary, cardiac and capillary circulations; and (d) stable for recirculation. A variety of potential ultrasound contrast agents have been or are now under development. Present and future ultrasound contrast agents should provide for increased diagnostic capabilities in a variety of normal and abnormal vessels and organs throughout the body. These agents will enhance tumor vascularity, delineate areas of ischemia, as well as improve visualization of vascular stenosis. Future developments with modification of ultrasound equipment should increase the capabilities of these agents to improve imaging as well as Doppler sensitivity.