Objective:To prospectively guide the change of chemotherapy regimen in mouse 5-fluorouracil (5-FU) resistance subcutaneous xenograft tumor model derived from gastric cancer patients by the early changes of MRI apparent diffusion coefficient (ADC), and to compare the difference of tumor load between ADC guided dressing change group and volume guided dressing change group.Methods:From January to June 2020, thirty patient-derived xenografts mouse models were established using 5-FU resistant gastric cancer cells coming from patients, and were randomly divided into experimental group and control group by AdaBoost algorithm, with 15 mice in each group. On the 26th day after transplantation, all mice began chemotherapy with 5-FU as the first-line chemotherapy drug, and underwent MR examination once every two days, including T 2WI and diffusion weighted imaging (DWI). Volumes of tumors were measured using an open-source software ITK-SNAP and values of ADC were measured on ADC maps. According to the change rate of tumor ADC value in the experimental group and the tumor volume growth rate in the control group, the replacement time of chemotherapy drugs was determined, and 5-FU was replaced by paclitaxel. The end point of the experiment was the day that the mice entered the cachexia state. Independent-sample t test was used to compare the difference of tumor load between the two groups. Results:After 5-FU treatment, the ADC value of the two groups both increased. The ADC value began to decline on the 4th day after chemotherapy, and the experimental group continued chemotherapy with paclitaxel instead of 5-FU at this time point. The tumor volume growth rate of the control group increased significantly on the 6th day after chemotherapy (from 8.6% to 16.1%), and the control group used paclitaxel instead of 5-FU chemotherapy at this time point. The observed end point was on the 18th day after chemotherapy. The tumor load of the experimental group [(1.82±0.09) cm 3] was lower than that of the control group [(2.01±0.09) cm 3], and the difference was statistically significant ( t=2.25, P=0.033). On the 16th day after chemotherapy in the experimental group and the 18th day after chemotherapy in the control group, the time of paclitaxel administration in both groups was 12 days. The tumor load in the experimental group [(1.61±0.12) cm 3] was also lower than that in the control group [(2.01±0.09) cm 3], and the difference was statistically significant ( t=2.03, P=0.040). Conclusions:For the subcutaneous transplantation model of 5-FU resistant gastric cancer mice, according to the early changes of tumor ADC value after chemotherapy, the replacement of chemotherapy drugs can obtain a lower tumor load, suggesting that it is a feasible method to optimize the chemotherapy regimen.

目的 探讨钆塞酸二钠(Gd-EOB-DTPA)对肝右叶局灶性病变及肝右叶体素内不相干运动(IVIM)双指数模型及拉伸指数模型测量的影响.资料与方法前瞻性纳入21例肝右叶病变患者22个病灶,分别于Gd-EOB-DTPA注射前后行相同肝脏IVIM序列扫描.分别测量肝右叶实质及右叶病变表观扩散系数(ADC)值、双阶单指数模型真扩散系数(Dmono)、假扩散系数(D*mono)、灌注分数(fmono)值、双阶双指数模型真扩散系数(Dbi)、假扩散系数(D*bi)、灌注分数(fbi)值、拉伸指数模型分布扩散系数(DDC)、拉伸指数(α)值;比较增强扫描前后各测量值的差异.结果 增强扫描前后肝右叶局灶性病变ADC、Dmono、D*mono、fmono、Dbi、D*bi、DDC、α值及肝右叶实质ADC、Dmono、D*mono、Dbi、D*bi、α值差异无统计学意义(P均＞0.05).增强扫描后肝右叶局灶病变fbi值和肝右叶实质fmono、fbi值升高,肝右叶实质DDC值降低,差异有统计学意义(t=-2.673、-5.055、-3.722、-2.447,P＜0.05).结论 注射Gd-EOB-DTPA对肝右叶局灶病变及肝右叶实质的ADC值、肝右叶病变IVIM参数中双阶单指数及双阶双指数的D值和D*值、fmono值、拉伸指数模型DDC值及α值定量评估无明显影响,对肝右叶实质背景fmono、fbi、DDC值的定量评估有一定的影响.

Objective To improve our knowledge of primary benign tracheobronchial tumors and increase the early diagnosis rate. Method The clinical and imaging features of 22 patients with benign tracheobronchial tumors were retrospectively analyzed. The lesions were surgically or pathologically confirmed as schwannomas(n=2),lipomas(n=3),hamartomas(n=3),leiomyomas(n=9),inflammatory myofibroblastoma(n=1),and pleomorphic adenomas(n=2).The early symptoms were concealed and atypical,accompanied by misdiagnoses at different time points.The tumors were located at trachea in 5 patients and at bronchus in 17 patients.All lesions manifested as intraluminal growth with mild to moderate enhancement,without thickening of the tracheobronchial wall.They had smooth margins and wide basements.The lesions were cast-shaped and occluded the lumen in 3 cases;in the remaining 19 cases,the lesions appeared as round or oval nodules. Conclusions Primary benign tracheobronchial tumors are rare.Patients with repeated cough and expectoration that respond poorly to treatment should be screened for benign tracheobronchial tumors.On CT,the benign tracheobronchial tumors are small intraluminal nodules with the smooth surface and wide basement,without thickening of the wall.

Objective To explore the atypical MRI findings of focal nodular hyperplasia ( FNH) of the liver.Methods Retrospective analyses were conducted for 13 cases ( 10 males and 3 females ) confirmed pathologically as FNH after surgery or biopsy with liver MRI examination from January 2012 to June 2015 in PLA General Hospital.Results There were 22 focal lesions in 12 cases, and diffuse pattern in 1 case.In the 22 focal lesions, there were 3 lesions with fatty change, 1 lesion with hemorrhage, 7 lesions with pseudo-capsule, regarding to dynamic contrast-enhanced pattern:12/22 lesions with gradually increasing enhancement, 3/22 lesions with rapid wash-in and wash-out, and 7/22 lesions with rapid wash-in and slow wash-out.The hepatocyte-specific agent examinations were performed in 20/22 lesions, and 20/20 lesions showed iso-to hyper-intensity to the liver parenchyma in the hepatocyte phase.There was 1 case ( female ) showing diffuse lesions with obvious fatty change, and all the lesions took up the hepatocyte-specific agent in hepatocyte phase.Conclusion The atypical focal nodular hyperplasia often occurs in middle age males and could demonstrate fatty change, hemorrhage, pseudo-capsule, various enhancement patterns.And when the FNH showed atypical routine MRI findings, the use of the hepatocyte-specific agent could facilitate the diagnosis.

To define correlations between the pathological grades of hepatocellular carcinomas (HCCs) and apparent diffusion coefficients (ADCs) derived using breath-holding diffusion-weighted imaging (BH-DWI).

Objective To explore diagnostic value of multi-slice spiral CT imaging features with respect to pancreatic neuroendocrine tumors (pNET) of different histological grades. Methods A retrospective analysis of preoperative abdominal plain CT and dual-phased contrast-enhanced CT was performed in 21 patients (median age, 47 years;12 males and 9 females) with pathologically proven pNET. age, gender, endocrine function, location and size of lesion, cystic change or necrosis, completeness of capsule, calcification, dilation of pancreatic duct were evaluated.CT attenuation-related parameters (plain CT value, relative density index, and CT value, CT value difference, enhanced percentage and enhancement index on arterial and portal phase) of each tumor were measured or calculated. All tumors were pathologically classified into three histological grades (G1, G2 and G3) based on mitotic count and ki-67 index. Kruskal-Wallis test was performed to compare differences of age, gender, endocrine function, morphological features among different grades. CT attenuation-related parameters were evaluated using Kruskal-Wallis or one-way analysis of variance (ANOVA). Results Twenty four pNET foci [grade G1 (n=13), G2 (n=7) and G3 (n=4)] were seen in the 21 patients. The difference of age, gender among different grades demonstrated no statistical significance (P>0.05). Nine lesions of G1 and 1 lesion of G2 demonstrated endocrine function, and the difference of endocrine function among three grades was statistically significant (χ2=8.355,P=0.012). For G1, G2 and G3, 11, 5 and 2 lesions were seen in uncinate process, pancreatic head and neck, respectively while 2, 2 and 2 lesions in pancreatic body and tail, respectively. The median maximum diameter of pNET of G1, G2 and G3 was 1.5, 2.5 and 6.7 cm, respectively;For G1, G2 and G3, 13, 4 and 0 lesions demonstrated intact capsule, respectively while 2, 3, and 3 lesions cystic degeneration and necrosis, respectivel; 0, 2 and 2 lesions calcification,respectively, 0, 1 and 2 lesions dilation of pancreaticobiliary duct, respectively, 0, 1 and 4 lesions sign of malignancy, respectively. The difference of size of lesion, completeness of capsule, calcification, and dilation of pancreatic duct showed statistical significance (P< 0.05). The difference of location of lesion and cystic change or necrosis displayed no significance (P>0.05). In addition, pNET of different grades demonstrated similar density and relative density index on plain CT. Regarding CT value, CT value difference, enhanced percentage and enhancement index on arterial and portal phase, the pNET of G2 showed highest value, while pNET of G3 lowest value, however, the difference about CT attenuation-related parameters among three grades showed no significant difference (P>0.05). Conclusion pNET of different histologic grades have some specific CT imaging features, which can facilitate an accurate diagnosis of pNET prior to therapy.

Objective To explore the clinical value of MRI in the preoperative diagnosis of T 1 stage renal cancer and in post-operative follow-up after partial nephrectomy .Methods Fifty-three patients (46 males, 7 females, aged 24 to 67 years old, mean age 49.96 ±10.06 years) were studied retrospectively .All patients were performed MR examination before operations , and the lesion's location, size, pseudo-capsule, peripheral infiltrating changes , tumor embolus in renal veins and metastasis were all recorded and comparied with pathologic results .As for the postoperative follow-up up-to-date, all patients received unenhanced MR scan in which 39 patients also received contrast-enhanced scan .And the operative region healing , recurrence and metastasis were recorded in every case.Moreover, all cases underwent partial nephrectomies .Results Fifty-three T1 stage renal cancers were analyzed preoperatively , in which 27 lesions were located in left kindy , and 30 in right side, what's more, 4 cases were bi-lateral.The lesion's location with renal hilum distance was 24 ~56 mm, average of 37 mm.Of all the cases, 50 (50/57, 87.7%) were peripheral type , 7 (7/57, 12.3%) were central type .The lesion size ranged from 8 mm to 60 mm, with an aver-age of 30 mm, and 3 (3/57 5.3%) lesions's size were greater than 40 mm.44 (44/57, 77.2%) lesions were bulged to cortex, while the other 13(13/57, 22.8%) lesions not.Also, 51(51/57, 89.5%) had pseudo-capsule, 6 (6/57, 10.5%) not.All the cases showed no renal vein tumor embolus , no lymphadenopathy in the perirenal and retroperitoneum space , and the perirenal fat space were all clear .The shape of the postoperative area appeared trangles or wedge-shaped in MRI followed up .Compared to the preoperation, the postoperative area of the original lesion showed enlarged in 7 cases (7/57, 12.3%), no change in 9(9/57, 15.6%), and diminution in 41(41/57, 71.9%).The enlarged area and the similar area all showed heterogenous signal intensity on T2 WI and DWI, with separation, and the diminution cases showed hypointensity on T 1 WI, T2 WI and DWI.No case showed recurrence and metastasis in the follow-up.Conclusion The clinical value of MRI is very important for the preoperative diagnosis and stage of T 1 stage renal cancer , indication assurance , modus operandi selection and for postoperative follow-up after partial ne-phrectomy .

PurposeTo quantitatively compare the apparent diffusion coefficient (ADC) values of 3.0T and 1.5T magnetic resonance (MR) diffusion-weighted imaging (DWI) protocols using regions of interest (ROIs) for the minimum ADC, largest solid part, and maximum diameter of lesions, for the detection of liver focal lesions.Materials and MethodsIn total, 26 patients with 28 liver focal lesions prospectively underwent both 1.5T and 3.0T DWI of the liver. The protocols included respiratory-triggered (RT), breath-holding (BH), and free-breathing (FB) acquisitions. The ADC values were measured at both field strengths using three methods: ROIs with the minimum ADC, the largest solid part, and the maximum diameter of lesions. Bland-Altman tests and paired t-tests were used to compare ADC values in the liver focal lesions obtained at 1.5T and 3.0T.ResultsThe 3.0T and 1.5T protocols differed significantly with regard to the ADC values of the RT, BH, and FB acquisitions, for ROIs of both the largest solid part (P = 0.005, P = 0.014, and P = 0.022, respectively) and maximum diameter of lesions (P < 0.001, P = 0.001, and P = 0.001, respectively).ConclusionWhen using DWI for quantitative analysis of liver focal lesions, field strength could exert a negative effect depending on the ROI. The ADC values from ROIs of both the largest solid part and maximum diameter of lesions may differ between 1.5T and 3.0T protocols.J. Magn. Reson. Imaging 2016;44:1320-1329.

目的 探讨儿童腹膜后(包括肾上腺区)节细胞神经瘤的CT表现,以提高对本病的认识.资料与方法 回顾性分析6例经病理证实的儿童腹膜后节细胞神经瘤的CT影像资料,包括病变部位、大小、形态、边界、密度、钙化、囊变及坏死、病灶强化幅度、病变与周围血管的关系等征象.结果 6例肿瘤均单发,3例位于腹膜后,3例位于肾上腺区,肿瘤大小平均为(7.7±5.1) cm.6例病灶CT平扫相对肌肉呈均匀低密度,CT值为(36±8)HU,1例合并细粒样钙化.所有病灶未见囊变或坏死.增强扫描l例动脉期轻度强化,5例未见明显强化,实质期6例病灶呈不同程度的轻、中度强化,增强幅度相对于平扫CT,CT值增加(23±9) HU.结论 儿童腹膜后节细胞神经瘤是一种边界清晰、密度较低、轻至中度渐进性强化的良性肿瘤,把握其影像特点有助于准确诊断.

OBJECTIVE:To evaluate the clinical value of magnetic resonance (MR) diffusion-weighted imaging (DWI) for diagnosing radiation-induced liver injury (RILI) and detecting changes in hepatic pathology at different post-irradiation times.METHODS:Male New Zealand white rabbits received no irradiation (C0, control group; n = 10) or irradiation of 50 Gy/10F once every other day by virtual three dimensional conformal radiotherapy (3D-CRT) for one day (C1; n = 10), three days (C2; n = 10), two weeks (C3; n = 10), one month (C4; n = 10) or two months (C5; n = 10). One member of all groups were sacrificed for DWI examination and pathologic study on post-irradiation day 1, day 3, week 2, month 1 and month 2. The apparent diffusion coefficient (ADC) values were measured using a range of b values (50, 300, 600, 800 and 1000 s/mm2).RESULTS:Hematoxylin-eosin (H-E) staining showed that livers of rabbits in the C3, C4 and C5 groups had the characteristic features of veno-occlusive disease. DWI examination showed that the irradiated livers of rabbits in C2, C3, C4 and C5 groups had significantly lower ADC values than the livers of the non-irradiated rabbits at b values of 300, 600, 800 and 1000 s/mm2 (P less than 0.05). When the b value was 600 s/mm2, the best negative correlation between ADC values and pathological stage was seen for the irradiated livers (Spearman's rank, r = -0.459, P less than 0.01). The threshold ADC value to distinguish the normal group (C0) from an irradiated group (more than or equal toC1) was 1.955 * 10-3 mm2/s at 600 s/mm2 b value. When the b value was 1000 s/mm2, the threshold ADC value to predict an irradiated group with normal H-E staining (C1) from an irradiated group with abnormal H-E staining (more than or equal toC2) was 1.5250 * 10-3 mm2/s; the ADC threshold value was 1.5150 * 10-3 mm2/s to predict groups C0-2 and groups C3-5.CONCLUSION:DWI has high sensitivity for detecting RILI at three days after irradiation with proper b values. Use of the ADC value is feasible for estimating the evolutionary process of pathological features of RILI damage. DWI may represent an important clinical tool for detection of early pathological changes in RILI.

OBJECTIVE:To evaluate the value of T2 mapping in monitoring the repaired cartilage after matrix-associated autologous chondrocyte implantation/transplantation (MACI/MACT).METHODS:Four patients (10 plug cartilages) were examined three times by T2 mapping at 1, 3, and 6 months using a 3.0 Tesla MR scan system. Quantitative mean (full-thickness) T2 values were calculated in the transplanted area and control cartilage. Paired t-tests were used to compare the T2 values between transplanted and control cartilage. For analysis of longitudinal T2 values, one-way analyses of variance were performed among 1, 3, and 6 months after MACI.RESULTS:The mean T2 values of the transplanted area at 1, 3, and 6 months after MACI were (82.40±15.23), (71.09±13.06), (53.80±4.86) ms, respectively. There were significant differences between the transplanted and control cartilage at 1 and 3 months (both P<0.01) after MACI, but not at 6 months (P=0.196). There were significant differences among T2 values of 1, 3, and 6 months after MACI in transplanted area (P=0.03).CONCLUSION:T2 mapping provides a useful tool for monitoring the biochemical development of the transplanted cartilage and can be used to evaluate the cartilage repair noninvasively.

目的:对ADC值诊断结节状及弥漫生长外周带前列腺癌的价值进行初步评价.方法:对病理证实的35例外周带前列腺癌及22例外周带非肿瘤性病变的最小ADC值进行回顾性分析.结果:诊断结节状外周带前列腺癌,两位评估者所获的ROC曲线下面积(AUCs)分别为0.713(95％CI:0.566～0.866)及0.748(95％CI:0.605～0.890),诊断弥漫生长的外周带前列癌,评估者1及2的AUCs分别为0.943(95％CI:0.854,1.033)及0.876(95％CI:0.729,1.023),当ADC截断值设为1.02×10-3 mm2/s时,两种形状外周带前列腺癌的诊断的正确率分别为67.4％～70.5％及84.0％～85.7％.结论:ADC值对于外周带弥漫生长前列腺癌的诊断价值较高,对于外周带结节状前列腺癌的诊断价值中等.

Objective To investigate the T2 values and knee thickness in healthy young adults using 3.0 T magnetic resonance imaging(MRI).Methods Totally 40 volunteers(18-30 years old)with body mass index between 18.5-24.0 kg/m2 were divided into two groups(22 men and 18 women)according to their gender.Also in addition,each group was divided into two subgroups(right knee and left knee).The T2 values and the thickness of the areas on the medial condyle of femur,the lateral condyle of femur,the medial tibial plateau,the lateral tibial plateau,and the patella of the knee cartilage were measured.Results The T2 values and the thickness of the right and left knee cartilages showed no significant differences between men and women(P0.05).Also,the T2 values in the five parts of the knee cartilage also were not significantly different between men and women(P0.05).However,the thickness of the 5 parts of the knee cartilage significantly differed between men and women(P0.05).Conclusions The thickness of the knee cartilage may different between male and female young adults.The T2 values of the cartilage may be not affected by the gender.