兔VX2肝肿瘤射频消融疗效评价——超声造影、增强CT与病理对比研究

目的 探讨超声造影(CEUS)与增强CT检查在评价肝肿瘤VX2肝肿瘤模型射频消融(RFA)疗效方面的作用. 资料与方法 9只兔VX2肝肿瘤模型作RFA治疗后1周同时作CEUS与增强CT检查,与病理作对照,比较CEUS与增强CT在评价RFA疗效的准确性. 结果 9只中8只病理发现残留肿瘤灶,1只完全消融,残留灶在CEUS与增强CT上均可见强化.3只炎性反应带能被CEUS正确评价,而增强CT将其中2只误认为是残留灶.1只残留灶位于肋骨下未能被CEUS检出.CEUS、增强CT、两者联合诊断的敏感率、特异性和诊断准确率分别为86%、88%、86%,90%、78%、85%,94%、75%、91%.三组之间差异均无统计学意义(P<0.05). 结论 CEUS与增强CT均能较可靠评价RFA疗效,两者具有良好的相关性和一致性; CEUS与增强CT联合评价可提高评价准确率.     

肝癌电磁波热凝治疗消融术后的CT表现分析

目的:分析肝癌电磁波热凝治疗(微波固化或射频消融)后的常见和特殊CT表现,提高对电磁波热凝治疗消融后肝脏形态改变和局部并发症的认识。方法:26例消融治疗后的肝癌患者,术后2周行CT扫描,3个月内复查CT,结合临床症状和实验室检查指标,分析射频消融治疗后肝脏形态的一般变化和出现局部并发症时的特殊征象。结果:电磁波热凝治疗消融后18例病灶呈术后正常改变,CT平扫为边界清楚、均质的低密度区,增强扫描无强化,而坏死区周边可见薄的环形强化,病灶范围较治疗前稍大,随治疗后的时间延长坏死区周边的环形强化逐渐减弱至消失,而中心坏死区仍为低密度,无强化,病灶较前逐渐缩小。消融后复发4例,CT表现为消融治疗区域周边的新发低密度灶。胆道损伤2例,CT表现为消融治疗区域周边肝内胆管扩张。肝内假性囊肿形成1例,CT示消融治疗区旁边缘锐利无强化的囊性灶;皮肤瘘道形成并胸腔积液1例,CT表现为消融治疗的针道不愈合,肝脏内病灶坏死区与体表相连通。结论:CT可准确地反映原发性肝癌电磁波热凝治疗消融后肝脏的形态学改变,有效观察局部并发症的发生情况,有助于提高对电磁波热凝治疗术后征象的认识。     

肝脏恶性肿瘤射频消融术后PET-CT早期复查的临床价值

目的 探讨肝脏恶性肿瘤射频消融术后早期行18F脱氧葡萄糖(18F-FDG)PET-CT复查的临床应用价值.方法 15例行射频消融术的肝脏恶性肿瘤患者均在术前2周内行全身PET-CT检查,并于术后24 h内行肝区PET-CT复查(早期PET-CT复查),了解消融效果.术后早期PET-CT复查,原病灶区影像上所显示的完全放射性缺损、局部核素浓聚及病灶周围环形核素浓聚分别代表肿瘤彻底坏死、局部肿瘤残留及病灶周围正常肝组织炎症反应.然后分别于术后1、3、6个月行PET-CT复查,6个月以后每隔半年复查一次.以最终的PET-CT检查结果为参考.结果 PET-CT早期复查影像显示,12例患者在原肿瘤病灶区表现为完全性放射性缺损,影像随访证实均无肿瘤组织残留;2例表现为病灶边缘结节状的核素浓聚,影像随访证实为残余瘤,并再次治疗干预;1例可见环形轻微核素浓聚,影像随访证实为炎症反应.结论 早期PET-CT复查影像,可以避开术后炎症反应的干扰、明确消融范围,能够及时、准确地评价肝脏恶性肿瘤射频消融术的效果,帮助临床制定进一步的治疗方案.     

~(18)F-FDG PET/CT对兔VX2肉瘤射频消融疗效的评价:以病理作对照

目的评价PET/CT在兔后肢VX2肉瘤射频消融(radiofrequency ablation,RFA)术后近期疗效中的价值。方法 16只载瘤兔(共32个肿瘤)随机分为两组:RFA治疗组和对照组(不作任何治疗),每组8只,16个肿瘤。在动物肿瘤模型制作后20天左右行射频治疗,治疗前1~3天、治疗后1周和4周进行PET/CT检查并于四周检查后处死,行病理学检查和免疫组织化学检测。结果 1 RFA术前肿瘤最大标准摄取值(standardized uptake value,SUVmax)为5.306±1.246,RFA术后1周、4周坏死区SUVmax分别为2.169±0.681、1.987±0.611,外周炎性反应SUVmax分别为2.681±0.353、2.331±0.461,均明显低于RFA治疗前(P0.05);RFA术后1周、4周残余瘤组织SUVmax(5.606±1.254、5.338±1.300)均明显高于炎性反应(P0.05);216个病灶RFA治疗后,经病理证实残留灶12例(75%),完全失去活性病灶4例;术后1周和4周,PET/CT分别发现残留灶15例(94%)和13例(81%),PET/CT和病理结果之间差异均无统计学意义(P0.05)。结论 PET/CT能够准确反应兔后肢VX2肉瘤射频消融术后的病理学变化,是评价RFA治疗早期疗效的一种理想方法。     

高渗盐水、冰醋酸及其混合物对肝脏射频消融增效作用的实验研究

目的 比较在体兔肝脏对高渗盐水、冰醋酸以及冰醋酸高渗盐水(AAHS)混合溶液对于增大射频消融(RFA)毁损区范围的效果,选择出最佳的消融增效剂.方法 30只大耳白兔分为6组,每组5只,A组单纯RFA;B组注射36%NaCl+RFA;C组注射50%冰醋酸溶液+RFA;D组注射50%AAHS溶液+RFA;E组单纯注射50%冰醋酸溶液;F组单纯注射36%氯化钠溶液.将兔分期处死后取出肝脏、固定.并对上述各种溶液对RFA的增效作用进行综合评价.结果 同其他各组相比.A组最低阻抗值最大(P<0.05),B、D组同C组最低阻抗间的差异有统计学意义(P<0.05),而B组与D组最低阻抗间差异无统计学意义(P=0.997).A组持续时间明显小于B、D组(P<0.05).而B组与D组持续时间之间的差异无统计学意义(P>0.05).C组与B、D组在射频持续时间上差异有统计学意义(P<0.05).B、C、D组较A组能产生更大的凝固坏死区(P<0.05).其中,D组凝固坏死区最大切面面积最大.与其他各组相比差异有统计学意义(P<0.05).而B组与A、C、E组比较其消融最大切面面积的差异也有统计学意义(P<0.05).在观察组兔术后1周CT扫描可见消融灶周边明显强化:术后3周CT扫描可见消融灶明显减小.观察组兔中共有6只发生了与手术相关的并发症(6/12:占50%):使用冰醋酸组的兔有4只(4/6)出现腹腔粘连和腹水,,而未使用冰醋酸组只有2例(2/6).结论 50%AAHS溶液注射同RFA联合比单纯RFA能获得更大的凝固坏死区范围,其对肝脏RFA的增效作用大于单一溶液的作用.     

原发性肝脏神经内分泌肿瘤的影像学表现

目的探讨原发性肝脏神经内分泌肿瘤的CT和MRI表现及其特征。方法回顾性分析经病理证实的8例原发性肝脏神经内分泌肿瘤患者的临床、病理及影像学资料。结果本组8例患者中,2例行MR检查,5例行CT平扫及增强检查,1例行CT平扫检查。单发病灶者4例,多发病灶者4例。肿瘤CT平扫均表现为肝内边界清楚的低密度肿块,病灶中央可见不规则形坏死区,3例病灶周围多发子灶,2例病灶周围血管受压推移;MRI上肿瘤表现为长T_1稍长T_2信号;7例增强扫描后病灶实质部分动脉期轻至中度强化,静脉期持续强化,中心坏死区无明显强化。结论原发性肝脏神经内分泌肿瘤具有一定的CT及MR影像特点,表现为肝内边界清晰的类圆形肿块,常伴中心坏死囊变及周围多发子灶,强化方式为延迟强化。     

射频消融联合无水乙醇注射在兔肝脏中的实验研究

目的 研究不同方式的射频消融(RFA)与无水乙醇注射(PEI)联合应用对正常兔肝脏的消融效果,并评价其安全性和实用性.方法 采用32只活体新西兰大白兔正常肝脏进行研究,分为4组,各组分别采用RFA-PEI(A组)、PEI-RFA(B组)、RFA(C组)和PEI(D组)处理,并于术前,术后1、3、7d抽血检查丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、血清肌酐(Cr)水平的变化情况.术后各组行肝脏增强CT扫描,计算各组消融灶体积.结果 术前各组血清ALT、AST、Cr水平差异无统计学意义(P＞0.05);术后1d各组血清ALT、AST与术前差异有统计学意义(P＜0.05);术后3d各组血清ALT、AST水平开始下降,术后7d各组ALT、AST与术前差异无统计学意义(P＞0.05),术后1、3、7d各组血清Cr与术前比较均差异无统计学意义(P＞0.05).A、B、C和D组的消融体积分别为(3.10 ± 1.10)mm3、(5.99±2.23)mm3、(0.77±0.15)mm3和(0.15±0.07)mm3,B组显著大于A、C和D组(P＜0.05).结论 PEI后RFA对于兔肝、肾功能影响小、并发症少,PEI-RFA治疗安全、有效;PEI-RFA组产生的消融体积明显大于RFA后PEI组、RFA组、PEI组的消融体积.     

PET/CT与MRI对肝脏转移瘤消融疗效评估的比较研究

目的 对比分析PET/CT与MRI对肝脏转移瘤消融疗效评估,探讨两种检查方法在临床中的应用价值.方法 搜集22例共32个转移灶行射频消融的肝脏转移瘤患者,均在1个月行全身PET/CT检查及MRI增强扫描,两种检查的间隔时间＜1周,随访及病理证实后对两种检查方法进行对比分析.CHISS软件运行X2检验结果及对比分析两种方法相关性,P＜0.05为两种检查方法差异有统计学意义.结果 经随访及病理证实治疗后活性病灶20个,完全失去活性病灶12个,MRI平扫加增强判断病灶有活性22例,完全失去活性病灶10例,PET/CT判断活性病灶14例,完全失去活性病灶18例.结论 经过统计分析两种检查方法无明显差别.在目前临床中对肝脏转移瘤射频消融治疗后活性判断,由于PET/CT对RFA转移病灶摄取受影响的因素较多,其对病灶活性判断并不优于目前应用较广的MRI平扫加增强扫描.     

^32P粒子植入对正常肝组织损伤及体内代谢的实验研究

目的观察32P-磷酸铬-聚L-乳酸(32P-CP-PLLA)粒子对正常犬肝组织损伤效应,及其体内代谢和缓释效应。方法Beagle犬12只,随机分为4个剂量组,A组185 MBq、B组370 MBq、C组740MBq,D组为空白对照假手术组。采用开腹将32P-CP-PLLA粒子植入犬肝脏内,3个月后处死。术前及处死前均行CT扫描,术前及术后1、2、4、8、12周进行血象及血清生化检查,B、C两组各选1只于代谢笼内饲养,术后1个月内每24 h测量粪便及尿液放射性计数率值(cpm),术后1、2、4、8、12周每组选1只犬行肝穿刺及SPECT韧致辐射显像,处死时行病理学检查。结果所有实验犬血象及血生化各项指标未见明显异常;术后30 d的排泄物放射性检查表明粒子在体内缓慢释放;尿、粪排出的放射性计数累积百分率分别为6.34%和11.64%;SPECT显像示无粒子移位现象;3个月后解剖发现粒子体积变小、质地松脆,CT、大体标本和病理学检查结果均发现随着剂量增大,肝脏内粒子植入部位毁损灶增大。32P-CP-PLLA粒子造成的局部肝损伤呈一球形灶:纤维化组织包绕坏死灶,外周可见一圈水肿带。结论32P-CP-PLLA粒子植入犬...     

肺肿瘤热消融治疗的CT影像演变与疗效评价

【摘要】　目的　分析肺肿瘤热消融治疗的CT影像表现及演变过程,探讨早期疗效评价的最佳时期和标准。方法　收集2017年1月至2020年6月浙江省肿瘤医院行肺肿瘤热消融治疗41例患者的临床资料,将患者分为完全消融组和不完全消融组。比较两组患者术后即刻、1、3、6、12个月的CT影像学特征,分析肺肿瘤热消融治疗后CT早期疗效评价的最佳时期和标准。结果　热消融术后即刻所有消融灶体积均较术前增大,病灶周围可见磨玻璃样阴影。完全消融组和不完全消融组患者磨玻璃样阴影最小宽度差异有统计学意义（P＜0.05）,诊断界值为3.9 mm时,AUC为0.871,敏感度为75.0%,特异度为90.3%。随时间延长,完全消融组患者消融灶体积逐渐缩小,最终表现为纤维条索、空洞、结节;不完全消融组患者消融灶体积先缩小后增大,呈结节或肿块样。两组患者术后1、3个月消融灶大小差异无统计学意义（P＞0.05）,术后6、12个月差异有统计学意义（P＜0.05）。两组患者术后即刻平扫CT值均较术前降低,术后1、3个月消融灶增强后CT强化幅度差异无统计学意义（P＞0.05）;术后6、12个月差异有统计学意义（P＜0.05）,完全消融组表现为轻度强化（＜10 HU）,不完全消融组表现为不均匀明显强化（＞15 HU）。结论　热消融术后即刻病灶周围磨玻璃样阴影最小宽度对疗效评价有较大的预测意义;消融灶大小变化和强化幅度是判断病灶治疗效果的主要影像指标;术后6个月是早期评价热消融治疗效果的最佳时期。     

Morphologic and functional changes in nontumorous liver tissue after radiofrequency ablation in an in vivo model: comparison of 18F-FDG PET/CT, MRI, ultrasound, and CT.

Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on (18)F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and (18)F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. METHODS: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities-MRI, CT, and ultrasound-and by (18)F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings. RESULTS: Immediately after radiofrequency ablation, no increase in (18)F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in (18)F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule. CONCLUSION: If performed immediately after radiofrequency ablation, (18)F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential.     

Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: evaluation with follow-up multiphase helical CT.

PURPOSE: To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation at long-term follow-up multiphase helical computed tomography (CT). MATERIALS AND METHODS: There were 43 nodular HCCs in 40 patients at follow-up CT performed not less than 12 months after RF ablation. All patients underwent follow-up multiphase helical CT immediately, 1 month, and then every 3 months after percutaneous RF ablation. The serial changes in attenuation, enhancement pattern, shape, other findings, and volume of the ablated lesions were analyzed at follow-up CT. RESULTS: Thirty-eight (88%) of 43 ablated lesions were of low attenuation, with absence of contrast material enhancement at immediate and 1-month follow-up CT, which is suggestive of successful treatment. The remaining five lesions (12%) showed peripheral nodular enhancement, suggesting residual viable tumor. Compared with volume changes at immediate follow-up CT, the mean percentages of volume change at 1, 4, 10, 16, and 19 months were 79%, 50%, 27%, 11%, and 6%, respectively. Of 43 ablated lesions, 24 (56%) were mostly round at immediate CT and remained unchanged at subsequent follow-up CT. Peripheral rim enhancement was seen in 34 (79%) of 43 lesions at immediate CT but resolved in all 34 lesions at 1-month follow-up CT. Other associated findings included iatrogenic arteriovenous shunt in 10 patients, perihepatic hemorrhage in three, and pneumothorax in one. CONCLUSION: Follow-up multiphase helical CT of HCCs treated with percutaneous RF ablation showed variable findings in the treated lesions and surrounding liver parenchyma.     

Comparison of FDG-PET, PET/CT and MRI for follow-up of colorectal liver metastases treated with radiofrequency ablation: initial results

PURPOSE: Morphologic imaging after radiofrequency ablation (RFA) of liver metastases is hampered by rim-like enhancement in the ablation margin, making the identification of local tumor progression (LTP) difficult. Follow-up with PET/CT is compared to follow-up with PET alone and MRI after RFA. METHODS AND MATERIALS: Sixteen patients showed 25 FDG-positive colorectal liver metastases in pre-interventional PET/CT. Post-interventional PET/CT was performed 24h after ablation and was repeated after 1, 3 and 6 months and then every 6 months. PET and PET/CT data were compared with MR data sets acquired within 14 days before or after these time points. Either histological proof by biopsy or resection, or a combination of contrast-enhanced CT at fixed time points and clinical data served as a reference. RESULTS: The 25 metastases showed a mean size of 20mm and were treated with 39 RFA sessions. Ten lesions which developed LTP received a second round of RFA; four lesions received three rounds of treatment. The mean follow-up time was 22 months. Seventy-two PET/CT and 57 MR examinations were performed for follow-up. The accuracy and sensitivity for tumor detection was 86% and 76% for PET alone, 91% and 83% for PET/CT and 92% and 75% for MRI, respectively. CONCLUSIONS: In comparison to PET alone, PET/CT was significantly better for detecting LTP after RFA. There were no significant differences between MRI and PET/CT. These preliminary results, however, need further verification.     

螺旋CT对射频消融治疗肝脏恶性肿瘤的疗效评价

目的　探讨螺旋CT在肝脏恶性肿瘤射频消融治疗后随访过程中的价值。方法　对 3 6例超声引导下经皮穿刺射频消融治疗的肝脏恶性肿瘤患者 (2 9例原发性肝癌和 7例转移性肝癌 )定期进行螺旋CT双期增强扫描检查 ,观察射频消融的效果及肿瘤复发的情况。结果　肿瘤残留或原位复发的主要征象是消融区的边缘呈带状或结节样强化 ,或在随访CT复查中 ,肿瘤的体积不断增大。在射频消融治疗后的首次CT复查中 ,2 8例 (77.8% )肿瘤出现完全坏死。在随后的CT随访复查中 ,2例 (5.6% )出现肝内原位复发 ,4例 (11.1% )出现肝内异位复发。结论　对于合适的肝脏恶性肿瘤 ,射频消融是一种疗效确切的肿瘤局部治疗方法 ,在其疗效评价和长期随访过程中 ,螺旋CT双期增强扫描是有效的影像检查手段     

Role of [18F]FDG-PET/CT after radiofrequency ablation of liver metastases: preliminary results

PURPOSE: Focal metastasis may be treated with radiofrequency ablation (RFA), a low invasive method yet limited by the lack of direct evidence of radicality of treatment. We, hereby, aimed at assessing the role of positron emission tomography-computed tomography (PET/CT) with fluoride radiolabeled deoxy-glucose ([(18)F]FDG) in RFA treatment success evaluation and early diagnosis of local relapse of liver metastasis after RFA procedure. METHODS: RFA was performed in nine patients on 12 liver metastasis, serially imaged through [(18)F]FDG-PET/CT and multidetector CT (MDCT) at 1, 3, 6, and 9 months after treatment. Eight lesions were also scanned with [(18)F]FDG-PET/CT at 1 week after treatment. Imaging analyses were performed on 47 [(18)F]FDG-PET/CT and 51 MDCT. Imaging reading outcomes were compared to each other and to biopsy tissue results when available. RESULTS: In one case, [(18)F]FDG-PET/CT revealed radiotracer uptake at RFA site a week after procedure. Negative concordant outcome was obtained on eight lesions at 1 month after RFA, on eight cases at 3 months, on four at 6 months, and on two cases at 9 months. Extra-liver (peritoneal) disease was detected in one case by both [(18)F]FDG-PET/CT and MDCT. In seven cases, [(18)F]FDG-PET/CT revealed the presence of local recurrence earlier than MDCT. In no cases did MDCT detect local relapse earlier than [(18)F]FDG-PET/CT. CONCLUSION: [(18)F]FDG-PET/CT may detect RFA treatment failure as well as local relapse after RFA earlier than MDCT.     

Central lower attenuating lesion in the ablation zone on immediate follow-up CT after percutaneous radiofrequency ablation for hepatocellular carcinoma: Incidence and clinical significance

Purpose

The purpose of this study was to evaluate the incidence of central lower attenuating (CLA) lesion in the ablation zone seen on immediate follow-up CT images after percutaneous radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), and the correlation of CLA lesions and local tumor progression (LTP).

Subjects and methods

The study group included 146 patients with 167 ablation zones that had undergone follow-up CT examinations for more than 12 months after percutaneous RFA. CLA lesions corresponding to index tumors and ablative margins (safety margins) were evaluated in the ablation zones seen on immediate follow-up CT including coronal and sagittal multiplanar reformatted (MPR) images with narrow window width settings.

Results

CLA lesions were depicted on 48 of 167 ablation zones (28.7%) on immediate follow-up CT images. Among the 48 ablation zones with CLA lesions, 27 (56.3%, 27/48) had ablative margins on all three of the orthogonal MPR images and they showed no LTP (0%) on follow-up CT examinations. Three of the ablation zones with CLA lesions (6.3%, 3/48) having an ablative margin on one plane only also showed no LTP (0%). LTP was observed in 2 of 18 ablation zones (11.1%) that had CLA lesions without ablative margins on all three planes. In the remaining 119 ablation zones without CLA lesions, 5 (4.2%, 5/119) showed LTP.

Conclusion

CLA lesions in ablation zones were occasionally (28.7%) seen on immediate follow-up CT images after RFA for HCCs. The presence of CLA lesions with ablative margins might be a negative predictor of LTP.     

Magnetic resonance imaging after radiofrequency ablation in a rodent model of liver tumor: tissue characterization using a novel necrosis-avid contrast agent

We exploited a necrosis-avid contrast agent ECIV-7 for magnetic resonance imaging (MRI) in rodent liver tumors after radiofrequency ablation (RFA). Rats bearing liver rhabdomyosarcoma (R1) were randomly allocated to three groups: group I, complete RFA, group II, incomplete RFA, and group III, sham ablation. Within 24 h after RFA, T1-weighted (T1-w) MRI was performed before and after injection of ECIV-7 at 0.05 mmol/kg and followed up from 6–24 h. Signal intensities (SIs) were measured with relative enhancement (RE) and contrast ratio (CR) calculated. The MRI findings were verified histomorphologically. On plain T1-w MRI the contrasts between normal liver, RFA lesion, residual and/or intact tumor were vague. Early after administration of ECIV-7, the liver SI was strongly enhanced (RE=40–50%), leaving the RFA lesion as a hypointense region in groups I and II. At delayed phase, two striking peri-ablational enhancement patterns appeared (RE=90% and CR=1.89%), i.e., “O” type of hyperintense rim in group I and “C” type of incomplete rim in group II. These MRI manifestations could be proven histologically. In this study, tissue components after RFA could be characterized with discernable contrasts by necrosis-avid contrast agent (NACA)-enhanced MRI, especially at delayed phase. This approach may prove useful for defining the ablated area and identifying residual tumor after RFA.     

Computed tomography appearances of hypervascular hepatic tumors after percutaneous radiofrequency ablation therapy

A retrospective review of the computed tomography (CT) findings of patients with hypervascular liver tumors (26 hepatocellular carcinomas and 2 metastases [1 periampullary carcinoma and 1 neuroendocrine tumor]) who underwent percutaneous ultrasound-guided radiofrequency ablation (RFA) was performed. CT images consisted of nonenhanced and dual-phase contrast-enhanced helical CT images performed on a multidetector CT scan. Findings indicative of adequate tumor ablation on multidetector CT scanwere complete nonenhancement of the treated tumor with or without faint, thin, peripheral rim enhancement. Ablated lesions that showed complete nonenhancement on initial and subsequent follow-up CT examinations either remained stable or became progressively smaller. Thick rim or nodular peripheral enhancement was indicative of tumor residual or recurrence.