评估低频超声辐照犬前列腺增生组织对射频消融灶大小的影响。

实验犬共9只，分为3组（每组各3只），对犬前列腺行射频消融术，实验组消融术前行低频超声辐照，对照组仅行射频消融术或仅行低频超声辐照；术后即刻行经直肠前列腺常规超声检查、超声造影及磁共振增强检查。低频超声辐照加射频消融组与仅行射频消融术的对照组的增强磁共振成像前列腺消融灶体积的比较采用t检验，低频辐照前造影剂达峰时间、曲线下面积与低频辐照比较采用配对t检验。

低频超声辐照后即刻超声造影显示，前列腺内造影剂达峰时间缩短，最大强度较辐照前减低，且造影剂持续时间变长，辐照后造影剂达峰时间由（28.55±10.88）s缩短至（14.81±5.15）s，差异有统计学意义（t=2.796，P=0.0189），时间-信号强度曲线曲线下面积由（2046.56±424.66）dB s缩小至（1454.82±458.12）dB s，差异有统计学意义（t=2.32，P=0.0427）。超声造影及增强磁共振均能准确评价前列腺射频消融灶大小。实验组消融后磁共振增强图像显示实验组消融灶体积为（1.27±0.21）cm³，仅行射频消融术的对照组消融灶体积为（0.73±0.18）cm³，差异有统计学意义（t=3.382，P=0.0277）；而仅行低频超声辐照的犬前列腺未出现消融灶。

低频超声联合微泡辐照能有效阻断增生前列腺组织内血流灌注量，联合射频消融治疗能有效增大消融灶体积。

To evaluate the effect of low frequency ultrasound on the volume of the radiofrequency ablation lesion in canine hyperplasia prostate tissue.

A total of 9 experimental dogs were divided into three groups (3 in each group). Radiofrequency ablation was performed on the canine prostates. Low-frequency ultrasound was performed before the ablation of the experimental group. Radiofrequency ablation or low-frequency ultrasound was performed only in the control groups. Then all experiment animals underwent routine rectal examination, contrast-enhanced ultrasonography and MRI. The volume of prostate ablation lesions in enhanced magnetic resonance imaging was compared between the low-frequency ultrasound irradiation plus radiofrequency ablation group and the control group with radiofrequency ablation only. Statistical analysis was performed using the t-test to compare the differences between groups.

Contrast enhanced ultrasonography (CEUS) performed immediately after low-frequency ultrasound irradiation showed that the time to peak of intra-prostatic contrast agent shortened, the maximum intensity decreased compared with those before irradiation [(28.55±10.88) s vs (14.81±5.15) s, t=2.796, P=0.0189], and the contrast agent duration increased [(2046.56±424.66) dB s vs (1454.82±458.12) dB s], the difference was statistically significant (t=2.32, P=0.0427). CEUS and MRI can accurately evaluate the size of the prostate radiofrequency ablation. The ablation volume of the experimental group after ablation was (1.27 ± 0.21) cm³ in the experimental group, while the volume of the ablation group in the control group was (0.73±0.18) cm³, and the difference was statistically significant (t=3.382, P=0.0277); however, the other group which were only exposed to low-frequency ultrasound did not show lesions.

Low frequency ultrasound irradiation can effectively block the blood flow in proliferative prostatic tissue, and combined with radiofrequency ablation can effectively increase the volume of ablation.