Objective To observe the relationship between diffusion-weighted imaging ( DWI) characteristics and chemoradiotherapy response in recurrence patients with radical hysterectomy .Methods 26 recurrence patients with radical hysterectomy were included .All underwent conventional MRI and DWI before and after chemoradiotherapy . Baseline tumor characteristics including recurrence site ,gross tumor volume ,necrotic area and the ADC value were re-corded.Focal regions of restricted diffusion were delineated as a separate ROI and ADC value was determined .Ima-ging features were compared between complete response group and partial response group .Results 12 patients had complete response ( CR group ) ,14 patients had partial response ( PR group ) .ADC valueafter chemoradiotherapy was significantly higher than that before chemoradiotherapy in PR patients .Compared with CR group ,PR group had a grea-ter gross tumor volume ,higher ADC value and more focal regions of restricted diffusion .Recurrence type and necrotic areas was no significant differences .Conclusion ADC value and focal regions of restricted diffusion adquired by DWI help to determine chemoradiotherapy response in recurrence patients with radical hysterectomy ,which is helpful for clinicians to predic treatment effect early .It has great significance for developing reasonable programs and impro-ving the therapeutic effect .

Objective To explore the diagnositic value of dual-phase contrast enhancement CT combined with virtual non-enhanced images by dual-energy CT in clear cell renal cell carcinoma.Methods Sixty patients who were suspected of clear cell renal cell carcinoma underwent non-enhanced CT and contrast enhancement CT of early interface-phase between cortex -medulla and parenchymal phase on a dual-energy CT.The true non-enhanced kidney CT(TNCT) was performed in a single-energy acquisition mode,but the dual-phase contrast enhancement CT were performed in a dual-energy mode of 80 kV and 140 kV respectively.The virtual non-enhanced CT ( VNCT ) images were derived from the data of early interfacephase using liver virtual non-contrast software.The diagnosises according to VNCT combined dual-phase contrast enhancement CT and dual-phase contrast enhancement CT only were made respeetively and compared with x2 test.Between the true non-contrast CT and the virtual non-contrast CT,the image quality was compared with Wilcoxon test ; The radiation dose of volume CT dose index ( CTDlvol ) and dose length product(DLP) in a single-phase and total examination,the mean CT HU values of the tumours werecompared with t test.Results The accuracy of VNCT combined dual-phase contrast enhancement CT was higher than that of dual-phase contrast enhancement CT only [93.3％ ( 56/60 ) vs.78.3％ ( 47/60 ) ; x2 =5.6,P ＜0.05].The detective ability (score) of VNCT was near to that of TNCT and the difference was not obvious( Z =0.00,P ＞ 0.05 ). The radiation dose of volume CT dose index ( CTDIvol ) and dose length product(DLP) in a single phase and total examination of VNCT[(8.85 ± 1.28) mGy,(196.45 ±21.12) mGy·cm,(17.69±2.35) mGy,(392.90±42.25) mGy · cm] were lower than that of TNCT [( 10.20 ± 1.44 ) mGy,( 218.29 ± 29.60 ) mGy · cm,( 30.61 ± 3.27 ) mGy and ( 654.86 ± 88.81 ) mGy ·cm],t =4.21,3.58,23.63,16.12 respectively,P ＜0.05.The mean CT HU values of tumours on VNCT images was higher than that on TNCT images and the difference was significant [(39.37 ± 6.35 ) vs.(34.94 ± 7.00 )HU,t =- 14.39,P ＜ 0.05].Conclusions The diagnositic value of dual-phase contrast enhancement CT combined virtual non-enhanced CT by dual-energy CT for clear cell renal cell carcinoma was obvious,most tumours can be diagnosed correctly,and the radiate dose can be decreased obviously,the normal single-energy non-enhanced and contrast enhancement CT might be replaced in the future.

OBJECTIVETo analyze the CT and MRI findings and pathological characteristics of retroperitoneal localized Castleman's disease and discuss the diagnostic and differential value of CT and MRI.

METHODSCT, MRI and clinical data of retroperitoneal localized Castleman's disease, proved by surgery and pathology, of 13 patients were reviewed. Among them, all the 13 cases received CT, and 4 cases received MRI examination.

RESULTSAmong the 13 cases, 12 cases were of hyaline vascular type, and one was of mixed type. All foci were single mass and most foci located in the periphery of the kidney. The maximum diameter was 4.2 cm to 8.6 cm and the mean diameter of all tumors was 5.9 cm. The outline of most tumors was clear and kidney-shaped. On unenhanced CT, 10 cases showed low density and 3 cases showed isodensity. On plain MRI, four cases showed iso-signal on T1WI, three cases showed slightly high signal on T2WI and one showed moderately high signal. The CT and MRI findings were similar on contrast enhanced scan. In arterial phase, 10 cases showed moderate enhancement, 2 cases showed significant enhancement and one case showed moderate enhancement. Five cases showed rather homogeneous enhancement and 8 cases showed heterogeneous enhancement.In venous phase, all the 13 tumors showed continuous enhancement. Eight cases showing heterogeneous enhancement in arterial phase showed expanded range, and among them two cases showed tending to be homogeneous enhancement. Six cases showed areas of low density without enhancement, and 9 cases were accompanied with single or multi-satellite punctuate or striped foci around the tumors.

CONCLUSIONDynamic contrast-enhanced CT and MRI combined with MR T2WI fat-suppression are of great importance in the diagnosis and identification of retroperitoneal localized Castleman's disease.

Adult ; Castleman Disease ; diagnostic imaging ; pathology ; surgery ; Female ; Humans ; Image Enhancement ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Radiographic Image Enhancement ; Retroperitoneal Space ; diagnostic imaging ; Retrospective Studies ; Tomography, X-Ray Computed