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Objectives: This study aimed to identify whether apparent diffusion coefficient (ADC) values and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters are helpful in distinguishing mesorectal tumor deposits (TD) from metastatic lymph nodes (MLN) in rectal cancer (RC). Methods: Thirty patients (59 lesions, including 30 TD and 29 MLN) with RC who underwent pretreatment-MRI between February 2016 and August 2018 were enrolled. The morphological features, ADC values, and semi-quantitative parameters of DCE-MRI, including relative enhancement (RE), maximum enhancement (ME), maximum relative enhancement (MRE), time to peak (TTP), wash-in rates (WIR), wash-out rates (WOR), brevity of enhancement (BRE), and area under the curve (AUC) were measured on lesions (TD or MLN) and RC. The parameters were compared between TD and MLN, tumor with and without TD group by using Fisher's exact test, independent-samples t-test, and Mann-Whitney U test. The ratio (lesion-to-tumor) of the parameters was compared between TD and MLN. Receiver operating characteristic curve analysis and binary logistic regression analysis were used to assess the diagnostic ability of single and combined metrics for distinguishing TD from MLN. Results: The morphological features, including size, shape, and border, were significantly different between TD and MLN. TD exhibited significantly lower RE, MRE, RE-ratio, MRE-ratio, ADCmin-ratio, and ADCmean-ratio than MLN. RE-ratio showed the highest AUC (0.749) and accuracy (77.97%) among single parameters. The combination of DCE-MRI and DWI parameters together showed higher diagnostic efficiency (AUC = 0.825). Conclusions: Morphological features, ADC values, and DCE-MRI parameters can preoperatively help distinguish TD from MLN in RC. Key Points: • DWI and DCE-MRI can facilitate early detection and distinguishing mesorectal TD (tumor deposits) from MLN (metastatic lymph nodes) in rectal cancer preoperatively. • TD has some specific morphological features, including relatively larger size, lower short- to long-axis ratio, irregular shape, and ill-defined border on T2-weighted MR images in rectal cancer. • The combination of ADC values and semi-quantitative parameters of DCE-MRI (RE, MRE) can help to improve the diagnostic efficiency of TD in rectal cancer. [ABSTRACT FROM AUTHOR]

Objectives: To summarize the experiences of CT-guided microcoil localization before video-assisted thoracoscopic surgery (VATS) and to investigate the risk factors associated with pleural marking failure. Methods: Totally, 249 consecutive patients with 279 pulmonary nodules who underwent CT-guided microcoil localization prior to VATS were enrolled in this study. According to intraoperative observation, all the nodules were divided into two groups. The clinical characteristics and microcoil localization procedure-related variables of the nodules were analyzed by univariate analysis and multivariate logistic regression analysis to screen the independent factors associated with procedure results. Results: Among the 279 nodules, 28 failed to observe the proximal end of the microcoil deployed on visceral pleura during VATS. The logistic regression revealed that needle-pleura angle (≤ 30°: OR = 39.022, p = 0.003), pleura-microcoil distance (≤ 10 mm: OR = 87.054, p < 0.001; 10~20 mm: OR = 10.088, p = 0.010), and presence of pleural indentation (OR = 21.623, p < 0.001) were independent risk factors for pleural marking failure. Conclusions: CT-guided microcoil localization for pulmonary nodules is a safe and effective procedure. Small needle-pleura angle (≤ 30°), pleura-microcoil distance (≤ 20 mm), and the presence of pleural indentation during the procedure are significant risk factors contributing to microcoil pleura marking failure. Key Points: • CT-guided microcoil localization for pulmonary nodules was a safe and effective procedure. • CT-guided microcoil localization for pulmonary nodules yielded low complication rates. • Small needle-pleura angle, short pleura-microcoil distance, and the presence of pleural indentation were contributing to pleura marking failure. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic potential of DW-MRI relative parameters for differentiation of rectal cancers with different Kirsten rat sarcoma viral oncogene homologue (KRAS) mutation status.Methods: Fifty-one patients with rectal cancer underwent diffusion-weighted MR imaging with eight b values. ADCs (including Max-ADC, Min-ADC and Mean-ADC) and IVIM parameters (D, pure diffusion; f, perfusion fraction; D*, pseudodiffusion coefficient) were respectively calculated by mono- and bi-exponential analysis. Patients were stratified into two groups: KRAS wild type and mutant. The DW-MRI-derived parameters between the KRAS wild-type group and KRAS mutant group were compared using the Mann-Whitney U test. Receiver-operating characteristic (ROC) analysis of discrimination between KRAS wild-type and KRAS mutant rectal cancer was performed for the DW-MRI-derived parameters.Results: Max-ADC, Mean-ADC and D values were significantly lower in the KRAS mutant group than in the KRAS wild-type group, whereas a higher D* value was demonstrated in the KRAS mutant group. According to the ROC curve, Mean-ADC and D* values showed moderate diagnostic significance with the AUC values of 0.756 and 0.710, respectively. The cut-off values for Mean-ADC and D* were 1.43 × 10-3mm2/s and 26.58 × 10-3mm2/s, respectively.Conclusion: Rectal cancers had distinctive diffusion/perfusion characteristics in different KRAS mutation statuses. The DW-MRI-derived parameters, specifically Mean-ADC and D*, show a moderate diagnostic significance for KRAS status.Key Points: • Rectal cancers with different KRAS mutation statuses demonstrated distinctive diffusion/perfusion characteristics. • Max-ADC, Mean-ADC and D values were lower in the KRAS mutant group. • A higher D* value was demonstrated in the KRAS mutant group. • IVIM-DW MRI may potentially help preoperative KRAS mutant status prediction. [ABSTRACT FROM AUTHOR]