Clinical Application Of Contrast Enhanced Ultrasonography In The Diagnosis Of Prostate Cancer

Objective:To evaluate the clinical application of contrast-enhanced ultrasound (CEUS)in the diagnosis of prostate cancer. (1) To evaluate the enhancement modality in prostate lesions with ultrasound contrast agent SonoVue. (2) Time Intense Curves(TICs) of prostate lesions and periphery tissue were drawn by the Auto tracking contrast quantification(ACQ) software to calculate the parameters to approach to the diagnostic value of their changes in prostate diseases. (3) To study the application value of CEUS guided biopsy in diagnosing prostate diseases.Methods:Sixty patients with elevated prostate specific antigen(PSA) were enrolled in the study. All patients were examined with transrectal ultrasound(TRUS)and then CEUS. Enhancement modality of prostate lesions and periphery tissue was analyzed and record in hard disc or(and) ultrasound work station with a bonus injection of 2.4ml SonoVue through periphery vein(median cubital vein).Low mechanical index(MI)contrast pulse sequencing(CPS)technique was applied in CEUS to receive the signal produced by contrast agent. After CEUS, nodule-target TRUS guided biopsy were performed on those patients with nodules in the prostate. And all of 60 patients underwent routine sextant system biopsy. The enhancement patterns of the lesions and prostates were observed on the examination record. Nodules and the surrounding tissue were selected as region of interest(ROI). TICs of ROIs were drawn with auto tracking contrast quantification(ACQ)software. Four parameters including arrival time(AT), time to peak(TTP), base intensity(BI), and peak intensity(PI) were measured on each case. Based on superior parameters, absolute peak intensity(ΔPI,ΔPI=PI-BI)and acceleration time (ACT, ACT=TTP-AT)as the two new parameters were calculated. All cases in the study were grouped to benign and malignant group referring to pathologic result. Statistic analysis were performed between the two groups.Results:Thirty-seven patients with benign lesions include 20 nodules and 22 diffuse benign prostatic hyperplasia(BPH)confirmed by pathology as well as 23 malignant lesions with 18 nodules and 5 diffuse changes. Fourteen, 3 and 1 of 18 nodules showed increased, equal, and decreased enhancement compared with surrounding outer gland tissue. The average TTP of 18 malignant nodules(26.03±3.12 s)was shorter than that of normal outer gland tissues(29.49±5.33 s)(P<0.05). The average absolute peak intensity(ΔPI, 13.72±5.07 dB)was higher than that of surrounding outer gland(10.08±3.72 dB)(P<0.05). Comparing to the benign nodules(30.98±7.15 s and 12.26±5.30 s, respectively), the TTP and ACT(16.9±6.1 s and 29.1±9.7 s, respectively)were more shorter(P<0.05). And PI of prostate cancer nodule(20.43±5.32 dB)was lower than that of benign lesion(23.51±2.51 dB)(P<0.05). Prostate cancer with no nodules show uneven enhancement in CEUS and undefined bouncary between external and inner gland. But the prostate with diffuse benign lesion had well-distributed enhancement and well-defined boundary. Grouped by pathology result, The accuracy, sensitivity, specificity, positive predict value(PPV), negative predict value(NPV)of CEUS were higher than those of TRUS while the misdiagnosis and missed diagnosis rate were lower.Conclusions:(1)CEUS could reveal the presence of vasculature within the lesions of prostate cancer objectively. CEUS could be helpful in the diagnosis of prostate and discrimination malignant lesions from benign ones.(2)Time and intensity parameters of ROI measures by ACQ software could be helpful to early diagnosis of prostate cancer.(3)Transrectal CEUS guided target biopsy could optimize the biopsy strategy and reduce the biopsy complication.