Objective To evaluate the diagnostic value of high resolution diffusion weighted imaging (RESOLVE-DWI) in adolescent primary osteosarcoma,and to compare the difference of image quality and apparent diffusion coefficient (ADC) value with conventional DWI echo planar imaging (EPI)-DWI.Methods Siemens Skyra 3.0T superconducting magnetic resonance imaging (MRI) scanner was used to collect MRI images of 30 patients suspected to be adolescent primary osteosarcoma.RESOLVE-DWI EPIDWI was performed.Meanwhile,the signal-to-noise (SNR) and ADC values of osteosarcoma tissues were measured and compared with the final pathological examination results.The image quality scores,SNR and ADC values of different diffusion weighted imaging sequences were tested by two independent samples t test.Results The overall quality of RESOLVE-DWI sequence images was significantly better than that of EPIDWI diffusion images,including 23 patients with RESOLVE-DWI scores ≥ 4 scored and 1 patients with EPI-DWI scores≥ 4,with significant difference(P ＜ 0.01).The mean ADC values of osteosarcoma tissues in RESOLVE-DWI sequence group and EPIDW sequence group were(856.16 ± 21.06) × 10-3 mm2 and (824.49 ±33.45) × 10-3 mm2,with no significant difference (P ＞0.05).The average SNR of RESOLVEDW1 group was significantly higher than that of EPI-DW1 sequence group (3.77 ± 0.51 vs 1.97 ± 0.23,P ＜ 0.01).Conclusions RESOLVE-DWI can improve the image quality and the SNR,and the ADC value of osteosarcoma tissue is not affected.It can provide more valuable diagnostic efficacy for the diagnosis of primary osteosarcoma in adolescents,and can be routinely used in the scanning of primary osteosarcoma in adolescents.

Objective To set up a living mice colonoscopy platform to establish an orthotopic model of colorectal cancer in mice under direct vision,and to observe its biological behavior such as metastasis.Methods Eighteen-week-old male C57/BL mice were anesthetized,and the intestinal lumen of the mice was examined by a self-developed living mice colonoscopy and Olympus URF-P5 ureteroscopy,respectively.The imaging effects of the two methods were compared.Human colon cancer HT-29 cells were injected into the colonic mucosa of BALB/c-nu mice under direct vision.The colonoscopy was performed on the 3rd,7th and 15th day after the injection to observe the tumor formation in the intestinal lumen.The mice were sacrificed when the body weight decreased significantly or cachexia appeared,and then the abdominal cavity was examined including the tumor formation and metastasis.Results The self-developed living mice colonoscopy platform can provide clear vision of enteric cavity,and no mice died in the colonoscopy examination.In vivo subcutaneous injection of HT-29 cells in mice was performed with a perforation rate of 15％,a mortality rate of 33.3％,a tumor formation rate of 62.5％,an abdominal metastasis rate of 60％,a liver metastasis rate of 25％,and an abdominal wall transfer rate of 25％.Conclusion The self-developed mice colonoscopy platform can be used for the study of colorectum in living mice.The imaging effect is no less than that of Olympus URF-P5 ureteroscopy.In addition,an orthotopic colorectal cancer model can be established by this platform combing with submucosal injection technology.

OBJECTIVES: With the increasing detection rate of lung nodules, the qualitative problem of lung nodules has become one of the key clinical issues. This study aims to evaluate the value of combining dynamic contrast-enhanced (DCE) MRI based on time-resolved imaging with interleaved stochastic trajectories-volume interpolated breath hold examination (TWIST-VIBE) with T₁ weighted free-breathing star-volumetric interpolated breath hold examination (T₁WI star-VIBE) in identifying benign and malignant lung nodules. METHODS: We retrospectively analyzed 79 adults with undetermined lung nodules before the operation. All nodules of patients included were classified into malignant nodules (n=58) and benign nodules (n=26) based on final diagnosis. The unenhanced T₁WI-VIBE, the contrast-enhanced T₁WI star-VIBE, and the DCE curve based on TWIST-VIBE were performed. The corresponding qualitative [wash-in time, wash-out time, time to peak (TTP), arrival time (AT), positive enhancement integral (PEI)] and quantitative parameters [volume transfer constant (Ktrans), interstitium-to-plasma rate constant (Kep), and fractional extracellular space volume (Ve)] were evaluated. Besides, the diagnostic efficacy (sensitivity and specificity) of enhanced CT and MRI were compared. RESULTS: There were significant differences in unenhanced T₁WI-VIBE hypo-intensity, and type of A, B, C DCE curve type between benign and malignant lung nodules (all P<0.001). Pulmonary malignant nodules had a shorter wash-out time than benign nodules (P=0.001), and the differences of the remaining parameters were not statistically significant (all P>0.05). After T₁WI star-VIBE contrast-enhanced MRI, the image quality was further improved. Compared with enhanced CT scan, the sensitivity (82.76% vs 80.50%) and the specificity (69.23% vs 57.10%) based on MRI were higher than that of CT (both P<0.001). CONCLUSIONS T₁WI star-VIBE and dynamic contrast-enhanced MRI based on TWIST-VIBE were helpful to improve the image resolution and provide more information for clinical differentiation between benign and malignant lung nodules.
Adult ; Humans ; Retrospective Studies ; Magnetic Resonance Imaging ; Plasma ; Tomography, X-Ray Computed ; Lung