Image-guided radiofrequency ablation of renal cell carcinoma

The incidence of renal cell carcinoma is rising with the increased number of incidental detection of small tumours. During the past few years, percutaneous imaging-guided radiofrequency ablation has evolved as a minimally invasive treatment of small unresectable renal tumours offering reduced patient morbidity and overall health care costs. In radiofrequency ablation, thermal energy is deposited into a targeted tumour by means of a radiofrequency applicator. In recent studies, radiofrequency ablation was shown to be an effective and safe modality for local destruction of renal cell carcinoma. Radiofrequency applicator navigation can be performed via ultrasound, computed tomography or magnetic resonance guidance; however, ultrasound seems less favourable because of the absence of monitoring capabilities during ablation. On-line monitoring of treatment outcome can only be performed with magnetic resonance imaging giving the possibility of eventual applicator repositioning to ablate visible residual tumour tissue. Long-term follow-up is crucial to assess completeness of tumour ablation. New developments in ablation technology and radiological equipment will further increase the indication field for radiofrequency ablation of renal cell carcinoma. Altogether, radiofrequency ablation seems to be a promising new modality for the minimally invasive treatment of renal cell carcinoma, which was demonstrated to exhibit high short-term effectiveness.     

Radiofrequency ablation for the treatment of renal cell carcinoma: initial experience

Purpose The aim of this retrospective study was to evaluate the clinical value of percutaneous radiofrequency ablation (RFA) for the treatment of renal cell carcinoma (RCC). Materials and Methods In a recent 3 years seven RCCs in six patients were treated by percutaneous RFA. RCC had been diagnosed based on the typical findings by computed tomography and/or magnetic resonance imaging. A cool-tip RF system (Vallylab) was mainly used with a RF2000 generator. The maximum tumor size ranged from 8 to 40 mm in diameter. The follow-up period was 14–36 months after initial RFA treatment. Results Complete disappearance of contrast enhancement during the early arterial phase was noted immediately after each session of percutaneous RFA. Two RCCs ≥ 3 cm in diameter showed tumor recurrence and required re-RFA during the follow-up period. In one patient, retroperitoneal hematoma was observed as a noteworthy complication. Conclusion Despite our limited number of patients, we believe that percutaneous RFA is clinically feasible and can be an alternative treatment of choice for RCC.     

Percutaneous radiofrequency ablation of renal cell carcinoma

Conventional curative therapy for renal cell carcinoma has been open nephrectomy. However, several less invasive and/or nephron-sparing procedures have been developed as alternatives in selected patients. The newest of these therapeutic modalities involves percutaneous image-guided ablation with straight or expandable needle applicators that deposit energy. Radiofrequency ablation is the modality for which there is the largest reported experience with percutaneous application, and involves the use of electrical current to generate frictional heating of tissue. Animal studies confirm the ability of radiofrequency ablation to cause regions of necrosis within normal kidney and in VX2 tumors. Clinically, radiofrequency ablation of small renal cell carcinoma is increasingly being performed in selected patients who are not ideal surgical candidates. Results are excellent for small exophytic tumors, but successful treatment is less likely as tumor size increases or the location becomes more central. Complete treatment of most tumors requires one or more overlapping ablations with the needle electrodes positioned so as to cause necrosis in the entire volume of tumor. The number of overlapping ablations and the position of the needle electrodes vary based on tumor size and geometry. For very large tumors, pre-ablation catheter embolization may enhance the results of ablation by decreasing blood flow and perfusion mediated cooling. Following ablation, imaging with CT or MR is performed to assess the result and to diagnose any residual tumor so that it can be treated. Because the tumor remains in situ, imaging follow-up continues indefinitely. The complication rate of radiofrequency ablation is favorable when compared to surgical techniques. Long-term survival data are not yet available.     

Complications of image-guided radiofrequency ablation of renal cell carcinoma: causes, imaging features and prevention methods

Radiofrequency (RF) ablation is an alternative treatment for renal cell carcinoma (RCC) in patients unable to undergo surgery. Although RF ablation has a low complication rate because of its minimally invasive nature, unintended heat may be conducted by several critical organs during ablation procedures, leading to a variety of complications. Major complications that usually require treatment include bowel injury, ureteral injury, massive bleeding and residual or recurrent tumour. Minor complications that may require only observation include pain, haematoma, haematuria, neuromuscular injury, pneumothorax, infarction and inflammatory tract mass. The most common cause of complications is the tumour’s proximity to neighbouring organs. In addition, careless electrode manipulation and the patient’s comorbidities may also lead to complications. To avoid many of these complications, the distance between the tumour and neighbouring organs should be widened using methods such as changing the patient’s position, using the RF electrode as a lever and hydrodissection. Furthermore, carefully manipulating the RF electrode and assessing the patient’s general condition help to prevent complications. In this review, we discuss the complications resulting from RF ablation of RCC with an emphasis on causes, imaging features and prevention methods.     

Spontaneous regression of pulmonary and adrenal metastases following percutaneous radiofrequency ablation of a recurrent renal cell carcinoma

The spontaneous regression of metastatic lesions from renal cell carcinoma (RCC) is extremely rare, but may be encountered following cytoreductive treatments. We report a case of a recurrent RCC with multiple metastatic lesions which spontaneously regressed after undergoing radiofrequency ablation of the renal tumor.     

射频消融治疗肾癌现状

近年来射频消融日益广泛应用于肾癌治疗,随着操作技术的不断发展,已在临床上取得显著的近期疗效,具有微创、安全、操作方便、并发症轻、患者痛苦少等特点。其未来发展的关键在于改进电极针,提高射频技术,联合c其他疗法等以提高疗效,并建立更合理的包括影像检查技术在内的疗效评价标准。     

Radiofrequency ablation treatment for renal cell carcinoma: early clinical experience

OBJECTIVE: To evaluate the early clinical experience associated with radiofrequency (RF) ablation in patients with renal cell carcinoma (RCC). MATERIALS AND METHODS: The RF ablation treatment was performed on 17 tumors from 16 patients (mean age, 60.5 years; range, 43-73 years) with RCC. The treatment indications were localized, solid renal mass, comorbidities, high operation risk, and refusal to perform surgery. All tumors were treated by a percutaneous CT (n = 10), followed by an US-guided (n = 2), laparoscopy-assisted US (n = 2), and an open (n = 2) RF ablation. Furthermore, patients underwent a follow-up CT at one day, one week, one month, three and six months, and then every six months from the onset of treatment. We evaluated the technical success, technical effectiveness, ablation zone, benign periablation enhancement, irregular peripheral enhancement, and complications. RESULTS: All 17 exophytic tumors (mean size, 2.2 cm; range, 1.1-5.0 cm) were completely ablated. Technical success and effectiveness was achieved in all cases and the mean follow-up period was 23.8 months (range, 17-33 months). A local recurrence was not detected in any of the cases; however, five patients developed complications as a result of treatment, including hematuria (n = 2), mild thermal injury of the psoas muscle (n = 1), mild hydronephrosis (n = 1), and fistula formation (n = 1). CONCLUSION: The RF ablation is an alternative treatment for exophytic RCCs and represents a promising treatment for some patients with small RCCs.     

Using an electrode as a lever to increase the distance between renal cell carcinoma and bowel during CT-guided radiofrequency ablation

The technique of using an electrode as a lever to increase the distance between renal cell carcinoma (RCC) and bowel during CT-guided radiofrequency ablation (RFA) is described. CT-guided percutaneous RFA was performed in two patients with two RCCs, which were in close proximity to the adjacent bowel. A sterile drape was placed on the electrode handle following appropriate electrode placement within the tumor in order to displace the kidney upward and to widen the distance to >5 mm between RCC and bowel (RCC-to-bowel distance). In patient 1, the RCC-to-bowel distance increased from 3 mm to 6 mm; in patient 2, from less than 2 mm to 6 mm. Follow-up CT performed 1 month after RFA demonstrated not only complete ablation of the two RCCs but also no thermal injury to the bowel adjacent to the tumors. In conclusion, an electrode might be used as a lever to increase RCC-to-bowel distance during CT-guided RFA by placing a sterile drape on it.     

Wide-bore 1.5 Tesla MR imagers for guidance and monitoring of radiofrequency ablation of renal cell carcinoma: initial experience on feasibility

This study was conducted to test and demonstrate the feasibility of magnetic resonance (MR)-guided radiofrequency (RF) ablation of renal cell carcinoma (RCC) using a 1.5 T whole-body scanner equipped with a wide-bore superconductive magnet. Two patients with contrast-enhancing renal masses were treated with multipolar RF ablation (Celon ProSurge). Applicator navigation and near real-time ablation monitoring were performed in a wide-bore 1.5 T scanner using adapted fluoroscopic and diagnostic sequences. In addition to T2-weighted imaging for ablation monitoring, perfusion-weighted images acquired with an arterial spin-labeling technique (FAIR-TrueFISP) were applied. Results were compared to a previous study on 12 patients performed at 0.2 T. Navigation and monitoring of RF ablation using the wide-bore system operating at 1.5 T were clearly improved compared to former experiences on a 0.2 T MR unit. Fluoroscopic and diagnostic images for MR guidance could be acquired with distinctly higher image quality and shorter acquisition time resulting in higher accuracy of applicator placement and shorter treatment time. Spin-labeling perfusion imaging exhibited good image quality, potentially providing additional clinically important information. MR-guided RF ablation of RCC can safely be performed in a 1.5 T wide-bore scanner offering higher image quality, shorter acquisition time, and new monitoring modalities not feasible at 0.2 T.     

Radiofrequency ablation of renal tumors

Percutaneous thermal ablation is increasingly applied in the therapy of renal tumors. Various techniques are available, allowing a safe and accurate therapy of renal tumors either using hyperthermia such as radiofrequency ablation (RFA), laser-induced thermotherapy (LITT) and microwave ablation (MW) or by hypothermia (cryoablation). As thermal ablation is a minimally invasive and nephron-sparing procedure, it is ideally suited for patients with a single kidney, multiple tumors or contraindications for resective surgery. Although cryotherapy is the most extensively studied technique, RFA has become the most accepted thermal ablation technique over the last years. Modern RFA probes allow ablation volumes between 2 and 5 cm in diameter. A major advantage of RFA is the ability to avoid tract bleeding and tumor seeding by coagulating the puncture channel during RF probe withdrawal. The increasing number of clinical reports on RFA of the kidney show the promising potential of renal RFA for minimally invasive tumor treatment. Due to its technical benefits, RFA seems to be advantageous when compared to cryoablation or laser ablation. However, there are no long-term follow-up or comparative data proving an equal effectiveness to surgery.     

Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours/=4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours/=4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.     

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with solitary kidney: 6 years experience

Objective

In this study we attempt to present our clinical experience in RFA under CT-guidance, in patients with renal cell carcinoma in a solitary kidney.

Material and Method

Between October 2000 and June 2005, 18 patients with solitary kidney and renal cell carcinoma underwent percutaneous CT-guided radiofrequency ablation in our institution. Tumors diameter ranged from 1 to 7 cm and there was no evidence of spread beyond the kidney. The RFA-system used was with expandable needle electrode (7 or 9 arrays). Technical success, recurrence and survival rate and complications were accessed. Patients were available for clinical and laboratory evaluation at a mean follow-up time of 31.2 months (range: 12–72 months).

Results

In all cases the electrode was successfully placed at the lesion. The 18 tumors were treated with totally 24 RFA sessions. In small (1–3 cm) exophytic tumors technical success was 85.7%. Residual disease was totally seen in 6/18 tumors which required a 2nd RFA session. The recurrence rate was 11.1% but no recurrence was noticed in tumors less than 3 cm in diameter. No major complications were observed. Serum creatinine values were normal in 17/18 patients till the 3rd-month follow-up. Survival ranged from 12 to 72 months.

Conclusion

RFA is an acceptable alternative for patients with small RCCs in a solitary kidney, which are not ideal candidates for surgical resection as their renal function must be preserved. They have an immediate solution to their clinical problem, under a minimally invasive therapy with no serious complications.     

Dual-energy CT in assessing therapeutic response to radiofrequency ablation of renal cell carcinomas

Purpose

To investigate the utility of dual-energy (DE) CT using virtual noncontrast (VNC) and iodine overlay (IO) images to assess therapeutic response to radiofrequency ablation (RFA) for renal cell carcinomas (RCCs).

Materials and methods

In this institutional review board-approved study (with waiver of informed consent), 47 patients with RCCs that underwent DECT after RFA were enrolled in this study. DECT protocols included true noncontrast (TNC), linearly blended DE corticomedullary and late nephrographic phase imaging. Two types of VNC and IO images were derived from corticomedullary and late nephrographic phases, respectively. To predict local tumor progression at RFA site, linearly blended and IO images were analyzed both qualitatively and quantitatively. Contrast-to-noise ratios (CNR) of renal cortex-to-RFA zones were calculated. The overall imaging quality of VNC images was compared with TNC images.

Results

The IO images from corticomedullary and late nephrographic phases showed excellent diagnostic performance (each sensitivity 100% and each specificity 91.5%) for predicting local tumor progression. The degree of enhancement of local tumor progression was not significantly different between linearly blended and IO images (P > 0.05). The mean CT numbers were not significantly different between TNC and VNC images (P > 0.05). In renal cortex-to-RFA site, CNR between linearly blended and IO images was not significantly different (P > 0.05). The VNC imaging quality from the two phases was given a good rating.

Conclusion

VNC and IO images from DECT may allow acceptable diagnostic performance with less radiation exposure as a follow-up imaging tool after RFA for RCC, compared to the linearly blended CT images.     

Renal cell carcinoma in patients with a solitary kidney after nephrectomy treated with radiofrequency ablation: Mid term results

This retrospective study aimed to evaluate the feasibility and effectiveness of radiofrequency ablation (RFA) in patients with solitary kidney for the treatment of renal cell carcinoma (RCC). Within 2 years 10 patients (seven males, three females; age 65 ± 8 years) were treated. All patients had a history of nephrectomy of the contralateral kidney. The indications for RFA were inoperability or high probability of complete renal failure after surgical enucleation of the tumor.13 tumors with a size between 1.9 and 4.2 cm (average 2.7 cm) were treated. In patients with a tumor diameter larger than 2.5 cm a transarterial embolization was performed prior to RFA to reduce heat sink effect and risk of bleeding. Therapeutical success was defined as a lack of contrast enhancement in follow up examinations and shrinking of the treated area. Furthermore all patients’ renal function was monitored.RFA of renal tumors under CT-fluoroscopy was feasible in all patients. Within the follow up (3 and 24 months) no tumor recurrence or major complication was detected. One patient developed another RCC and was successfully treated with a second RF-ablation. None of the patients developed renal failure with the need of hemodialysis. In one of the patients a hemorrhage into the surrounding tissue was noticed, which stopped spontaneously.RFA is a valuable and effective therapeutical option in patients with solitary kidney suffering from inoperable renal cell carcinoma. The complication rate is small and an excellent tumor control can be achieved without deterioration of the renal function.     

肾透明细胞癌的CT表现

目的分析肾透明细胞癌的CT影像特点。方法回顾性分析经病理证实的肾透明细胞癌16例,从病灶数目、大小、形态、强化方式及与邻近结构关系等方面总结其CT影像特点。结果本组16例均为单发病灶,多位于肾皮质,形态多为圆形或类圆形,多凸出肾轮廓之外,平均4.7cm(2.2~10cm不等),伴或不伴邻近结构受累;增强扫描大多数(12例)动脉期明显不均质强化,静脉期及分泌期强化程度降低,低于周围肾实质,即典型的"快进快出"式强化,1例动脉期中等度强化,2例仅轻度强化,1例肿瘤内形成动静脉瘘。本组病例其中1例为囊性肾透明细胞癌,内可见多发点状及条状钙化,增强后呈中等强化,囊内容物不强化。结论 CT扫描是肾透明细胞癌的重要检查手段,其较特征性的动脉期强化方式是与其它类型肾癌相鉴别的重要参考依据。     

小肾癌临床诊疗体会

目的探讨小肾癌的诊断和治疗方法,比较不同手术方法的优缺点。方法分析2000年8月～2007年8月收治的24例小肾癌的临床表现、诊断、治疗及预后并结合有关文献进行讨论。结果24例中全部手术治疗,18例行根治性肾切除术,6例行保留肾单位肾肿瘤切除术,术后均经病理证实。20例获得随访,16例无癌存活,最长已超过7年。结论小肾癌多为B超偶然发现,术前B超、CT、肾动脉造影综合分析明确诊断;手术方式依据具体情况采取根治性切除术（RN）或保留肾单位手术（NSS）;预后主要取决于肿瘤的分期和分级。     

Radiofrequency Ablation of Renal Tumors: Four-Year Follow-Up Results in 47 Patients

Objective

To retrospectively evaluate the intermediate results of radiofrequency ablation (RFA) of small renal masses (SRMs).

Materials and Methods

Percutaneous or laparoscopic RFA was performed on 48 renal tumors in 47 patients. The follow-up studies included a physical examination, chest radiography, creatinine level, and contrast-enhanced CT or MRI. To confirm the pathologic criteria of complete ablation, 35 patients underwent a follow-up biopsy. Recurrence was defined as contrast enhancement on imaging studies after 3 months, lesion growth at subsequent imaging, or viable cancer cells on follow-up biopsy.

Results

Technical success was achieved in 43 (89.6%) of 48 renal tumors. The mean tumor size was 2.3 cm and the mean follow-up period was 49.6 months. Repeated RFA was necessary in 5 tumors due to incomplete ablation. The overall complication rate was 35.8%, of which 96.2% were mild complications. Serum creatinine levels at 12 months after RFA did not differ from those before RFA (1.28 vs. 1.36 mg/dL). Four patients were found to have recurrence at various follow-up intervals, and distant metastasis was not found in any cases.

Conclusion

RFA appears to be a useful treatment for selected patients with SRMs. Our 4-year follow-up results disclose an excellent therapeutic outcome with RFA, while achieving effective local tumor control.     

Radiofrequency ablation of renal cell carcinoma

Small renal cell carcinomas of less than 4 cm diameter have been detected increasingly in asymptomatic patients because of the widespread use of cross-sectional imaging. Radical or partial nephrectomy is generally considered the reference for the treatment of a solitary renal cell carcinoma. However, for those patients who are not candidates for surgery, minimally invasive procedures may be desirable. Although percutaneous radiofrequency ablation for the treatment of renal cell carcinoma is a recent innovation, the results of preliminary clinical series and animal studies are encouraging, and show it to be technically feasible with minimal morbidity. In this article, we review the technique, indications, imaging findings, as well as the results of clinical and animal studies of radiofrequency ablation for the treatment of renal cell carcinoma.     

Radiofrequency ablation of osseous metastases for the palliation of pain

A number of different methods have been proposed for pain relief in cancer patients with bone metastases, each with different indications, contraindications and complications (systemic analgesics, bisphosphonates, antitumor chemotherapy, radiotherapy, systemic radio-isotopes, local surgery and vertebroplasty). The ideal treatment has to be fast, safe, effective and tolerable for the patient. CT-guided radiofrequency (RF) ablation may fulfill these criteria. Our experience in the treatment of 30 patients (34 lesions) with painful bone metastases using RF ablation was assessed. There was a significant decrease in the mean past-24-h Brief Pain Inventory (BPI) score for worst pain, for average pain and for pain interference during daily life (4.7, 4.8 and 5.3 units respectively) 4 and 8 weeks after treatment. There was a marked decrease (3 out of 30 patients 4 and 8 weeks after treatment) in the use of analgesics. CT-guided RF ablation appears to be effective for treatment of painful bone metastases.     

肾透明细胞癌与肾乳头状癌、嫌色细胞癌MRI表现的对照研究

目的 探讨MR动态增强扫描对肾癌亚型的鉴别诊断价值.方法 搜集77例经病理证实的肾癌患者资料,其中透明细胞癌(CCRCC)55例,乳头状癌(PRCC)14例,嫌色细胞癌(CRCC)8例,回顾性分析各亚型肿瘤患者MR平扫及动态增强扫描表现并与病理对照,根据肿瘤及肾皮质增强前后的皮质期、实质期及延迟期信号变化,分别进行百分比测量、肿瘤-肾皮质增强指数计算,并采用单因素方差分析和LSD法进行比较.结果 CRCC多数信号均匀(7/8);CCRCC及PRCC多数信号不均(分别为51/55和13/14)、常见坏死(36/55和7/14),PRCC最常见出血(9/14)及囊变(9/14).动态增强各期CCRCC强化程度最高,强化模式呈"快进快退",CRCC轻至中度强化,PRCC强化最轻,两者均呈渐进性延迟强化.CCRCC、PRCC及CRCC皮质期信号变化分别为(296.15±60.27)%、(79.70±18.84)%和(119.56±40.76)%,实质期分别为(236.33±58.31)%、(122.81±27.35)%和(163.06±33.91)%,延迟期分别为(216.83±46.72)%、(117.55±20.63)%和(179.72±32.89)%;三者皮质期的肿瘤-皮质增强指数分别为1.26±0.34、0.33±0.12及0.54±0.10,实质期分别为0.92±0.23、0.41±0.23及0.62±0.15,延迟期分别为0.76±0.14、0.35±0.11及0.69±0.12,各亚型增强各期的信号变化(F值分别为940.931、124.515、38.194,P值均＜0.01)、肿瘤-皮质增强指数(F值分别为798.625、78.308、73.699,P值均＜0.01)差异均有统计学意义.3种亚型的MRI表现与病理学所见基本相符.结论 CCRCC、PRCC及CRCC的MRI动态增强有一定特征性的表现,与其病理特点密切相关,在肾癌亚型的鉴别诊断上有着较高的临床应用价值.

Abstract：

Objective To investigate the differential diagnostic features of subtypes of renal cell carcinoma(RCC) using dynamic contrast-enhanced MRI(DCE-MRI).Methods The MRI appearances of 77 RCCs, including 55 clear cell RCCs(CCRCC),14 papillary RCCs(PRCC) and 8 chromophobe RCCs(CRCC), were retrospectively analyzed and compared with findings of pathology. DCE-MRI was conducted in each case after intravenous administration of contrast agent. Region of interest measurements (cortical, nephrographic and delayed Phases) of signals within tumor and uninvolved renal cortex were used to calculate percentage signal intensity change and tumor-to-cortex enhancement index, and the data was analyzed by AVONA and t test. Results On unenhanced and enhanced MRI, most CRCCs showed homogeneous signal(7/8). CCRCC and PRCC often show inhomogenous signal with necrosis(36/55, 7/14). Hemorrhage and cystic degeneration were often found in PRCC (9/14). On the cortical, nephrographic and delayed phase images, CCRCCs showed greater signal intensity change[(296.15±60.27)%, (236.33±58.31)% and (216.83±46.72)%,respectively than PRCCs (79.70±18.84)%, (122.81±27.35)% and (117.55±20.63)%, respectively], and CRCCs showed intermediate change [(119.56±40.76)%, (163.06±33.91)% and (179.72±32.89)%, respectively].A phenomenon of quick staining and quick fainting was observed in CCRCCs. Both of CRCCs and PRCCs showed delayed enhancement. The tumor-to-cortex enhancement index at the cortical, nephrographic and delayed phases was highest for CCRCCs (1.26±0.34, 0.92±0.23 and 0.76±0.14, respectively), lowest for PRCCs (0.33±0.12, 0.41±0.23 and 0.35±0.11, respectively), and intermediate for CRCCs (0.54±0.10, 0.62±0.15 and 0.69±0.12, respectively,P＜0.01). The degree of enhancement was significantly different among the 3 subtypes at the every contrast enhanced phase (F=940.931, 124.515 and 38.194, P＜0.01), so was the tumor-to-cortex enhancement index(F=798.625,78.308 and 73.699, P＜0.01). There was a good consistency between MR appearances of the 3 RCC subtypes and pathological characteristics. Conclusion DCE-MRI could distinctly show imaging features of CCRCC, PRCC and CRCC, which were related to their pathological characteristics, and these features were helpful in predicting a specific subtype of RCC.