Ablation of High-Intensity Focused Ultrasound Assisted with SonoVue on Rabbit VX2 Liver Tumors: Sequential Findings with Histopathology, Immunohistochemistry, and Enzyme Histochemistry

Background  We investigated sequential effects of HIFU ablation combined with contrast agent SonoVue by using histopathology examination, immunohistochemistry, and enzyme histochemistry. Materials and Methods  Forty rabbits with VX2 liver tumors were subjected to HIFU ablation. Before ablation, a bolus injection of 0.2 mL SonoVue was administrated in group II (n = 20), and normal saline solution was injected in group I (n = 20). On day 0, 3, 7, and 14 after ablation, 5 animals in each group were sacrificed. The tissue in ablated zone, transient zone (within 3 mm around ablated area), and surrounding zone (beyond 3 mm around ablated area) were collected. Coagulated volume measurement, hematoxylin-eosin staining, immunohistochemistry of Ki 67, Bcl-2, CD54, and MMP-2 to determine cell proliferation and tissue repair, and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) and succinic dehydrogenase (SDH) staining to evaluate tissue viability were performed. Results  The coagulated volume in group II at each time point was larger than that in group I (P < .05). After day 3, hematoxylin-eosin staining demonstrated necrosis in ablated zones and increasing surrounding fibra bands in group I and group II, while increasing expression of Ki 67, Bcl-2, CD54, and MMP-2 in transient zones was detected using immunohistochemistry in both groups (P > .05). NADPH-d and SDH staining showed dramatic decrease of enzyme activities in ablated zones immediately after ablation, while residual viable tissues in ablated zones of group II were less than those of group I (P < .05). Conclusion  Contrast agent SonoVue enables improvement of HIFU ablation on rabbit VX2 liver tumors.     

载阿霉素的液-固相变型原位凝胶注射治疗兔VX2肝癌HIFU消融后残癌

目的观察载阿霉素液一固相变型原位注射凝胶（DOX-ISFI）治疗高强度聚焦超声（HIFU）消融兔、,x2肝癌后残癌的疗效。方法以24只兔建立VX2肝癌模型,对肿瘤行HIFU不全消融,随机分为HIFU消融与DOX—ISFI联合治疗组（HIFU＋DOX—ISFI组）、HIFU消融与空白液一固相变原位注射凝胶联合治疗组（HIFU＋N—ISFI组）,每组12只,比较两组肿瘤生长率、PCNA表达情况,并以冰冻切片荧光显像观测药物瘤内分布。结果处理后HIFU＋DOX—ISFI组肿瘤生长明显减慢,其生长率明显低于HIFU＋N—ISFI组（P〈O．05）;HIFU十D0X-ISFI组肿瘤增殖指数明显低于HIFU＋N—ISFI组（P〈0．05）;荧光显像姓示药物从注射中心向剧围呈阶梯状分布。结论DOXISFI能钉效治疗HIFUiVX2肝癌后的残癌。     

Validation of Power Doppler Versus Contrast‐Enhanced Magnetic Resonance Imaging Quantification of Joint Inflammation in Murine Inflammatory Arthritis

Contrast‐enhancement magnetic resonance imaging (CE‐MRI) of synovial volume is the radiographic gold standard to quantify joint inflammation; however, cost limits its use. Therefore, we examined if power Doppler‐ultrasound (PD‐US) outcomes of synovitis in tumor necrosis factor transgenic (TNF‐Tg) mice correlate with CE‐MRI. TNF‐Tg mice underwent PD‐US of their knees to measure the joint space volume (JSV) and power Doppler volume (PDV), and the results were correlated with synovial volume determined by CE‐MRI. Immunohistochemistry for CD31 was performed to corroborate the PD signal. Synovial volume strongly correlated with both JSV and PDV (p < 0.01). CD31⁺ blood vessels were observed in inflamed synovium proximal to the joint surface, which corresponded to areas of intense PD signals. JSV and PDV are valid measures of joint inflammation that correlate with synovial volume determined by CE‐MRI and are associated with vascularity. Given the emergence of PD‐US as a nonquantitative outcome of joint inflammation, we find JSV and PDV to be feasible and highly cost‐effective for longitudinal studies in animal models. Furthermore, given the increasing use of PD‐US in standard clinical practice, JSV and PDV could be translated to better quantify joint flare and response to therapy in patients with rheumatoid arthritis (RA). © 2014 American Society for Bone and Mineral Research.     

Microbubbles improve the ablation efficiency of extracorporeal high intensity focused ultrasound against kidney tissues

Objective  The necrosis rate is low when ablating kidney tissues with extracorporeal high intensity focused ultrasound (HIFU), and this drawback has been limiting the application of ultrasonic therapy. The aim of the present study was to determine whether microbubbles increased the ablation efficiency in vivo. Methods  Goat kidneys were exposed to HIFU (control group) or microbubble-assisted HIFU (experimental group). Microbubbles were intravenously injected before focused ultrasound exposure. The linear scan was employed and tissue ablation was performed in manner of a clinical regime. The necrosis rate was determined 24 h after HIFU. Pathological examinations were performed to confirm tissue necrosis and to determine whether there were unaffected tissues within the exposed volume. Results  The necrosis rate was increased in experimental group (4.17 ± 1.33 vs. 9.32 ± 2.27 mm³/s, P = 0.0007). Ablated tissues formed a hemorrhagic volume on gross examinations, and the boundary between treated and untreated areas was sharp. There was no intact tissue within the exposed volume. Hemorrhage frequently occurred in insonated parenchymas. Destructed ghost cells just inside the demarcation were full of vacuoles, when introducing microbubbles. In control group, the volumes of ablated tissues varied drastically between animals despite a same treatment template. Conclusion  Microbubbles increased the ablation efficiency of HIFU against kidney tissues. A preoperative regime might poorly predict the therapeutic outcome. T. Yu and D. Hu contributed equally to this paper.     

高强度聚焦超声联合超声造影剂消融肝脏VX2移植瘤的实验研究

目的 探讨高强度聚焦超声(high intensity focused ultrasound,HIFU)联合超声造影剂(ultrasound contrast agents,UCA)治疗肝癌时的最适消融范围. 方法构建新西兰兔肝VX2移植肿瘤模型.51只模型兔分为3组:HIFU联合UCA沿肿瘤边缘消融肿瘤(A组)、消融肿瘤及肿瘤周围2 mm内的组织(B组)、消融肿瘤及周围4mm内的组织(C组).比较治疗后靶组织的病理情况、血清丙氨酸氨基转移酶(ALT)水平、肝内、肺及腹腔的转移情况以及生存期的差异.结果 HIFU联合UCA治疗后,各组靶区肿瘤组织均发生凝固性坏死;治疗后3 d、5 d,C组患者ALT显著升高,组间比较差异有统计学意义(F=12.933、18.37,均P＜0.01),C组最高;治疗后14 d,B组、C组ALT降至正常,组间比较差异无统计学意义(F=0.043,P＞0.05),A组ALT水平高于B组和C组(F=17.2,P＜0.05).治疗后两周肝内、肺及腹腔转移率A组均明显高于B组和c组(分别x2=9.918、6.300、7.6701,均P＜0.05),B组和C组差异无统计学意义(均P＞0.05),平均生存期A组(29 4±5.4)与B组(48±13.6)、C组(51±12.1)差异均有统计学意义(P＜0.05),B组和C组差异无统计学意义(P>0.643).结论 HIFU联合UCA在消融移植瘤周围组织2mm以上时可明显降低治疗后转移率,延长荷瘤兔的生存时间.     

A microbubble agent improves the therapeutic efficiency of high intensity focused ultrasound: a rabbit kidney study

Eighty kidneys (40 left and 40 right kidneys) of New Zealand rabbits were ablated using high intensity focused ultrasound (HIFU), (14,300 W/cm², 1.0 MHz). Kidneys were randomly divided into two groups. HIFU was performed in the manner of linear scan in both groups. Prior to HIFU, normal saline solution and isovolumetric microbubble agent were administrated intravenously in groups I and II, respectively. HIFU was finished in all left kidneys and in 26/40 right ones. The therapeutic efficiency was reflected using necrosis rate (cubic centimeters per second), which was the tissue volume of coagulative necrosis per 1 s HIFU exposure. In both groups, predetermined volumes were damaged without harming overlying tissues. Necrosis rates were increased in group II both in left (0.0089±0.0107 vs. 0.0493±0.0777, P=0.0323) and in right (0.0039±0.0055 vs. 0.0162±0.0168, P=0.0248) kidneys. Pathological examinations confirmed that there were no intact tissue focuses within exposed regions in either group. These findings suggested that the microbubble agent improved the therapeutic efficiency of HIFU. Hemorrhage and hyperemia were also detected on the margin of the ablated tissues (both in cortex and medulla) in both groups.     

高强度聚焦超声联合纳米微泡造影剂对兔VX2乳腺移植瘤辐照效果的影响

目的观察高强度聚焦超声（HIFU）联合纳米微泡对兔VX2乳腺移植瘤辐照效果的影响。方法制备纳米微泡,于光镜、电镜下观测微泡的大小、形态、分布及稳定性。采用Zeta SIZIER 3000电位仪测定微泡的粒径、电位。60只健康纯种雌性新西兰白兔,麻醉后种植VX2肿瘤于双侧乳腺组织内。2周后,选取乳腺区肿瘤组织直径大小为10mm的兔进行实验,随机分为实验组（HIFU＋纳米微泡）和对照组（HIFU＋磷酸盐缓冲液）,辐照剂量150 W,辐照时间5s,记录HIFU辐照前后灰阶变化,辐照后行HE染色观察坏死区域大小,并进行统计学分析。结果成功制备纳米微泡,其理化性质稳定,粒径大小合理,电位均衡。实验组靶区平均灰度差明显高于对照组（P〈0.05）。HE染色示实验组发生凝固性坏死范围明显大于对照组（P〈0.001）。结论纳米微泡能明显增强的损伤效果。     

高强度聚焦超声治疗VX2骨肿瘤的免疫变化

目的　探讨高强度聚焦超声 (HIFU )治疗骨肿瘤前后的免疫学变化。方法　将新西兰大白兔分为HIFU治疗组 (2 3只 )及正常对照组 (10只 ) ,对HIFU治疗组兔建立VX2移植性骨肿瘤模型 ,2周后接受HIFU治疗 ,于不同时间处死 ,免疫组织化学染色观察HSP70表达的变化 ,并在治疗前后抽血检测CD2 5变化。结果　治疗前肿瘤组织HSP70阳性表达细胞数量少 ,治疗后即刻直到 2 1d一直呈强阳性表达且阳性表达的细胞数明显增加。治疗前CD2 5为 7.83± 2 .0 3与正常兔 13 .18± 3 .47比较差异有显著性 (P <0 .0 5 ) ;治疗后增高为 15 .5 5± 2 .69,与治疗前比较差异有非常显著性 (P <0 .0 1)。结论　HIFU治疗后骨恶性肿瘤组织HSP70、CD2 5的数量增多 ,可递呈特异性抗原给T细胞 ,刺激T细胞增殖 ,提高机体抗肿瘤的免疫作用     

对比观察脂质纳泡与微泡在高强度聚焦超声消融兔肝中的增效作用

目的观察正常兔肝中脂质纳泡与微泡对高强度聚焦超声(HIFU)消融效果的影响,探讨纳泡的应用价值。方法采用机械振荡法联合低速离心制备纳泡,观察和分析纳泡及微泡的形态、大小及分布。18只健康新西兰兔随机分为3组:HIFU+生理盐水组、HIFU+微泡组及HIFU+纳泡组,耳缘静脉注入各溶液15s后开始HIFU辐照,辐照功率为180 W,辐照时间5s,观察HIFU辐照前后回声变化,检测靶区组织的凝固性坏死体积以及微细结构变化,并作统计学分析。结果制备的脂质纳泡粒径均一,纳泡、微泡的平均粒径分别为(588.00±53.02)nm、(3058.00±545.20)nm;HIFU+微泡组与HIFU+纳泡组,靶区凝固性坏死体积[(124.26±16.72)mm3,(121.35±11.25)mm3]差异无统计学意义(P0.05),但均显著大于HIFU+生理盐水组(62.49±4.54)mm3(P均0.05);各组坏死组织微细结构均严重破坏。结论脂质纳泡具有与微泡相同的HIFU增效作用,为纳泡在HIFU技术中的深入研究提供实验依据。     

高强度聚焦超声治疗兔肾VX2肿瘤的实验研究

目的探讨高强度聚焦超声（ＨＩＦＵ）治疗肾肿瘤的效果。方法采用兔肾ＶＸ２肿瘤模型进行ＨＩＦＵ辐照。辐照后不同时期处死动物以观察其病理变化。另以辐照组及对照组动物各６只,于２周后处死,比较肿瘤生长及肺转移的情况。结果ＨＩＦＵ辐照后肿瘤细胞立即发生凝固性坏死,电镜下亦见到不可逆的破坏。２周后有４只动物的肿瘤原发灶已被完全破坏;另２只靶区外有少量肿瘤残存,其体积为６２．８ｍｍ３和９．４ｍｍ３,而对照组的肿瘤平均体积为（１７５１．１±３５３．７）ｍｍ３。辐照组有２只（３３％）发生肺转移,转移结节数为９和３;对照组全部发生肺转移,转移结节数为５２±３４。两组差异有显著性。结论ＨＩＦＵ对兔肾ＶＸ２肿瘤有很强的杀伤作用。     

Evaluation of color Doppler in guiding prostate biopsy after HIFU ablation

OBJECTIVE: Transrectal ultrasound cannot accurately depict early cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. We evaluated transrectal color Doppler (CD) in guiding post-HIFU prostate biopsy. METHODS: Prostate CD-guided sextant biopsies were obtained in 82 patients who had undergone prostate HIFU ablation for cancer, 24 of whom had hormone therapy before the treatment. At the time of biopsy, a subjective CD score was given to all biopsy sites (0=no flow; 1=minimal flow; 2=suspicious flow pattern). CD findings were compared with biopsy results. RESULTS: CD was a significant predictor of biopsy findings, according to univariate and multivariate site-by-site analysis. However, only 36 of 94 sites with residual cancer had positive CD findings, and thus, negative CD findings should not preclude random biopsy. There was a significant interaction between CD diagnostic capability and a history of hormone therapy before HIFU treatment. CD was a significant and independent predictor of biopsy findings in patients who had not received hormone therapy (odds ratio: 4.4; 95%CI: 2.5-7.9; p<0.0001), but not in those who had (odds ratio: 1.3; 95%CI: 0.5-3.4; p>0.5). CONCLUSION: Biopsy taken in CD-positive sites were 4.4 times more likely to contain cancer in patients who did not receive hormone therapy. CD could not reliably depict cancer recurrence in patients with history of hormone therapy.     

高强聚焦超声消融兔腹主动脉旁肝肿瘤对腹主动脉的影响

目的观察高强聚焦超声(HIFU)消融兔腹主动脉旁肝肿瘤对腹主动脉的影响。方法对43只实验兔建立腹主动脉旁VX2肝肿瘤模型,于MR引导下行HIFU消融肿瘤,通过彩色多普勒超声观察消融前、消融后即刻、2h和6h腹主动脉充盈情况,测量血流峰值血流速(PSV)、平均血流速度(Vm)、平均血流量、阻力指数(RI)和搏动指数(PI)变化;病理观察消融前及消融后即刻腹主动脉的改变情况。结果共对40只实验兔成功建立腹主动脉旁肝肿瘤模型。消融后即刻腹主动脉血流通畅,未见明显狭窄、塌陷或闭塞。较之消融前,消融后即刻腹主动脉PSV、Vm和平均血流量明显减慢,RI和PI明显上升(P均0.05),之后逐渐恢复,于消融后6h恢复至消融前水平(P均0.05)。病理学检查示消融后即刻腹主动脉无损伤。结论 HIFU消融腹主动脉旁肿瘤可一过性改变腹主动脉血流动力学,而对管壁无明显损伤。     

Ultrasound Monitoring of a Novel Microwave Ablation (MWA) Device in Porcine Liver: Lessons Learned and Phenomena Observed on Ablative Effects Near Major Intrahepatic Vessels

Background  Microwave ablation (MWA) is postulated to have several advantages over other thermoablative modalities in the treatment of hepatic tumors. Herein, we use an in vivo porcine model to determine the effect of hepatic blood flow on a novel MWA applicator. Methods  Four 100-kg pigs underwent hepatic MWA (2,450 MHz, 100 W, 4 min) using a 5.7-mm diameter applicator (Microsulis Americas, Sulis™ V) inserted near large intrahepatic blood vessels. Real-time monitoring was performed using 3, 5, and 12 MHz diagnostic ultrasound transducers. The ablated zones were sectioned for gross and histological processing. Results  Ablation zones were uniform in shape and size (3–4 cm) and related to power deliver only. Gross and microscopic examination revealed direct extension of ablation zones to the margin of major hepatic blood vessels and occasionally beyond the intended target. Of note, a momentary acoustic white-out occurred around the probe at 25 ± −1 s in every ablation. Discussion  The Sulis V^TM MWA applicator produced uniform zones of ablation that remain unaffected by convective heat loss. The applicator induced a reproducible but temporary event as seen by ultrasound. Further study is warranted to define the physics, benefits, limits, and clinical safety of this new MWA technology.     

高强度聚焦超声治疗兔肾癌细胞株VX2的CT动态观察

目的 评估CT在高强度聚焦超声治疗兔VX2肾癌近期随访中的价值。方法 纯种新西兰白兔14只，建立原位肾癌动物模型。所有兔行CT检查后随机分成2组：对照组（5只），行高强度聚焦超声（HIFU）假照射，1月后CT检查；治疗组（9只），HIFU治疗后1周、1个月和2个月行CT检查。结果 （1）肿瘤强化：治疗前，所有肿瘤都有强化。对照组肿瘤在假照射后1个月依然都有强化；治疗组在治疗后1周，66．7％的肿瘤强化消失；治疗后1个月，88．9％的肿瘤强化消失；治疗后2个月和1个月相比肿瘤强化无明显变化。（2）肿瘤钙化：治疗后1月，治疗组77．8％的肿瘤出现钙化，对照组肿瘤始终无钙化。（3）肿瘤体积：对照组兔处死前的末次CT检查测得肿瘤体积和解剖后测得肿瘤体积比较，配对t检验，差异无统计学意义（P＞0．05）；同法比较治疗组肿瘤体积，差异无统计学意义（P＞0．05）。（4）治疗前CT测得体积和HIFU治疗点数之间有较好相关性（r=0．667，P＜0．05）。（5）病理观察：治疗后肿瘤细胞凝固性坏死，随访期中示纤维化、钙化改变；未治疗肿瘤生长旺盛。病理和CT结果一致。结论 CT检查可以为制定HIFU治疗计划提供参考；CT可以作为HIFU治疗肾癌后良好的随访手段；CT随访宜在治疗后1个月进行。     

高强度聚焦超声治疗弥漫性子宫平滑肌瘤病

目的探讨高强度聚焦超声(HIFU)在弥漫性子宫平滑肌瘤病(DUL)治疗中的安全性及有效性。方法回顾性分析单独采用HIFU治疗的20例DUL患者的临床资料,治疗后3天内采用MR检查评价疗效;治疗后3、6个月行彩色多普勒超声和子宫肌瘤症状量表(UFS)评分随访;分析治疗中、治疗后的不良反应。结果治疗后MRI显示20例患者消融体积(279.63±177.44)cm3,平均消融率为(32.35±3.74)%,治疗后3、6个月平均子宫体积缩小(24.87±5.08)%、(28.38±6.77)%;20例患者治疗前UFS为(18.25±4.38)分,治疗后3、6个月UFS分别减少(6.05±2.91)分、(7.60±3.52)分。治疗中20例(20/20,100%)患者均有治疗区疼痛,15例(15/20,75.00%)患者诉骶尾部疼痛,6例(6/20,30.00%)患者诉皮肤发烫;治疗后所有并发症均好转,未发生需要住院治疗的并发症。结论 HIFU治疗DUL近期内安全、有效。     

建立兔靠近腹主动脉VX2肝癌模型

目的建立兔邻近腹主动脉VX2肝癌模型,为高强度聚焦超声（HIFU）消融肝脏大血管旁肿瘤研究选择最佳建模时间点提供实验依据。方法采用手术直视下组织块包埋法对45只新西兰大白兔于肝门处接种VX2瘤块,接种后第14、21、28天行MRI,观察成瘤率、肿瘤体积和肿瘤一腹主动脉间距。结果接种后动物存活率为92．11％（41／45）,成瘤率为95．12％（39／41）。MRI示接种后第14天T2WI呈高信号,增强后VIBEFST1WI示肿瘤明显强化;第21天肿瘤T2WI呈高信号,肿瘤不均匀强化;第28天肿瘤边缘环形强化,中心无强化,肿瘤出现继发性坏死;肿瘤体积随时间逐渐增大,肿瘤一腹主动脉间距逐渐减小,差异均有统计学意义（P均〈0．05）。结论直视下组织块包埋法建立兔邻近腹主动脉VX2肝癌模型操作简单、重复性好、成功率高,肿瘤接种后21天为研究HIFU消融肝脏大血管旁肿瘤作用的最佳时间点。     

Ultrasound image based visual servoing for moving target ablation by high intensity focused ultrasound

Background

Although high intensity focused ultrasound (HIFU) is a promising technology for tumor treatment, a moving abdominal target is still a challenge in current HIFU systems. In particular, respiratory‐induced organ motion can reduce the treatment efficiency and negatively influence the treatment result. In this research, we present: (1) a methodology for integration of ultrasound (US) image based visual servoing in a HIFU system; and (2) the experimental results obtained using the developed system.

Materials and methods

In the visual servoing system, target motion is monitored by biplane US imaging and tracked in real time (40 Hz) by registration with a preoperative 3D model. The distance between the target and the current HIFU focal position is calculated in every US frame and a three‐axis robot physically compensates for differences. Because simultaneous HIFU irradiation disturbs US target imaging, a sophisticated interlacing strategy was constructed.

Results

In the experiments, respiratory‐induced organ motion was simulated in a water tank with a linear actuator and kidney‐shaped phantom model. Motion compensation with HIFU irradiation was applied to the moving phantom model. Based on the experimental results, visual servoing exhibited a motion compensation accuracy of 1.7 mm (RMS) on average. Moreover, the integrated system could make a spherical HIFU‐ablated lesion in the desired position of the respiratory‐moving phantom model.

Conclusions

We have demonstrated the feasibility of our US image based visual servoing technique in a HIFU system for moving target treatment.     

Contrast-Enhanced Magnetic Resonance Angiography in the Early Period After Kidney Transplantation

Our objective was to evaluate the usefulness of three-dimensional (3-D) contrast-enhanced (CE) magnetic resonance angiography (MRA) to assess renal parenchyma, arterial inflow stenosis, and peritransplant fluid collections in the early period after kidney transplantation (KT). Between January 2010 and April 2011, we examined a consecutive series of 144 renal transplants using 3-D CE MRA at 14 days after KT. MRA showed parenchyma infarctions (n = 17, 11.8%), arterial inflow stenoses (n = 23, 16%), lymphoceles (n = 14, 9.7%), and hematomas (n = 6, 4.2%). The degree of renal transplant artery inflow stenosis was graded qualitatively based on diameter criterion; <50% = mild, 50% to 70% = moderate, and >70% = severe in 10 (6.9%), 5 (3.5%), and 8 (5.6%) subjects, respectively. The study recipients were divided into 3 groups according to the degree of renal artery inflow stenosis (group I: normal; group II: mild and moderate, <70%; group III: severe, >70%). Among group III patients who underwent digital subtraction angiography, 5 had percutaneous transluminal angioplasty or stenting performed after 1 month. Their mean resume creatinine levels at 1, 6, and 12 months after transplantation were not significantly different from those in the other groups (P = .391, .447, .110). The prevalence of graft loss (n = 2) was high in group III (P = .012), although the frequency of acute rejection episodes was not different among the groups (P = .890). The incidences of renal parenchyma infarction, peritransplant fluid collection and arterial inflow stenosis were unexpectedly high in the early period after KT. Thus, 3-D CE MRA provided a rapid global assessment of the renal parenchyma, transplant arterial system, and peritransplant fluid collection that can be helpful to detect or exclude many causes of renal transplant dysfunction.     

Tumor ablation therapy of liver cancers with an open magnetic resonance imaging-based navigation system

Background  As minimally invasive treatments for liver cancers, percutaneous ablation therapies represent a valid alternative to liver resections, especially in patients with poor liver function. Recently, image-guided surgical and interventional procedures using open magnetic resonance imaging (MRI) have been introduced. Methods  We performed percutaneous ablation therapy for 51 nodules of liver cancer in 34 patients using a navigation system based on open MRI. During the ablation therapy, the ultrasonography (US) probe, needle, and tumor were displayed on the MR image. Immediately after the procedure, the therapeutic effect was evaluated by open MRI. Results  In all cases, percutaneous puncture into the tumors was successful, even in the case of tumor undetectable by US. Mean fiducial registration error was approximately 3 mm. MR images captured after the procedure clearly demonstrated the ablated area. No mortality or major complications occurred, except for mild hemorrhage, pyrexia, and ascites. Conclusions  We developed a novel navigation system integrating US and MR images using open MRI for percutaneous ablation therapy of liver cancers. The presented system allows a safe and accurate approach to liver cancers, especially certain tumors that cannot be adequately visualized by US, and an evaluation of therapeutic results immediately after the procedures.     

CD74 Is a Novel Prognostic Factor for Patients with Pancreatic Cancer Receiving Multimodal Therapy

Background  Pancreatic ductal adenocarcinoma (PDAC) is still one of the most fatal cancers, although its prognosis has improved recently with the introduction of multimodal therapy. To further develop effective treatment for PDAC, establishment of prognostic indicators for patients receiving multimodal therapy is essential. Methods  Sixty-eight patients receiving curative extended resection combined with preoperative chemoradiation and postoperative chemotherapy for primary PDAC were selected. Immunohistochemistry using anti-CD74 antibody on paraffin-embedded tissue samples was performed, and cases were divided into two groups according to the ratio of CD74-positive cells: expression level I, CD74-positive cells <70%; level II, CD74-positive cells ≥70%. The correlation of CD74 expression level with clinicopathological features and overall survival was evaluated. Results  Forty-seven (69.1%) and 21 (30.9%) patients showed level I and II CD74 expression, respectively. Patients with level II CD74 expression showed a higher rate of lymphatic permeation (P = 0.04) and perineural invasion (P = 0.01) compared with those with level I expression. Patients with level I CD74 expression had a significantly better survival rate than those with level II (P = 0.003). Among the patients with pathological tumor–node–metastasis stages I and II, those with level I CD74 expression showed a significantly better prognosis than those with level II (P = 0.006). Multivariate analysis revealed CD74 expression level and vascular permeation of carcinoma as independent prognostic indicators. Conclusions  CD74 expression proved as a useful prognostic indicator for PDAC treated with multimodal therapy.