ABSTRACT
Pancreatic cancer is a malignant tumor,and the clinical manifestations are not characteristic,so it is difficult to diagnose at an early stage, and it has a poor prognosis. Image technology has been widely used in clinical,with mature technology,and the application of image technology not only confined to the image display,but also has become a hot spot of research, including dynamic contrast enhancement magnetic resonance imaging (DCE－MRI),intravoxel incoherent motion ( IVIM),CT perfusion imaging,which could analyze quantitatively the permeability and microvascular of lesions,to improve the sensitivity of diagnosis,and to assess quantitatively the effect of drugs,radiation and chemotherapy.
ABSTRACT
Objective The aim of this study was to investigate the diagnostic value of the intravoxel incoherent motion (IVIM) for discriminating nonmetastatic from metastatic mediastinal lymph nodes in lung cancer.Methods IVIM was performed preoperatively on 66 patients with lung cancer during October 2015 to June 2016 in Capital Medical University Affiliated Beijing Chaoyang Hospital.Preoperative examination including the chest MRI scan,chest CT,head MRI,bone scan-ning and the cardiopulmonary function.None of the patients was undergone any kind of treatment about the cancer before the examinations,the neoadjuvant chemotherapy or radiation therapy,immunotherapy and gene targeted therapy were included.Measured the short axis diameter and the IVIM parameters of the mediastinal lymph nodes,apparent diffusion coefficient(ADC),diffusion coefficient(D),pseudo-diffusion coefficient(D *),and perfusion fraction(f).All the patients underwent the lobectomy or wedge resection and lymph node dissection or systematic sampling.By comparing the IVIM parameters of the nonmetastatic and metastatic mediastinal lymph nodes according to the pathological examination,draw the ROC curves to find the best cutoff value for diagnosis.And 42 cases were used to comparing the value of the MRI and CT in differential diagnosis.Results MRI measured 184 groups mediastinal lymph nodes,including 164 groups without metastasis,20 groups with metastasis.The ADC,D,D *,f values and short axis diameter of the nonmetastatic lymph nodes(n =164) were(2.880 ± 0.785) × 10-3 mm2/s,(0.670 ± 0.179) × 10-3 mm2/s,(0.383 ± 0.123) × 10-3 mm2/s,0.422 ± 0.119,(6.546 ± 1.932) mm,respectively,and (1.897 ±0.657) × 10-3 mm2/s,(0.472 ±0.210) × 10-3 mm2/s,(0.354 ±0.130) × 10-3 mm2/s,0.412 ±0.090,(7.510 ± 2.773) mm respectively for the metastatic lymph nodes (n =20).The ADC and D value of the nonmetastatic lymph nodes were significantly higher than the metastatic lymph nodes(P ＜0.01).While the other paraneters(D *,f,and short axis diameter) between the two groups did not show significantly different.Optimal cutoff values(area under the curve,sensitivity,and specificity) for distinguishing metastatic from nonmetastatic lymph nodes were as follows:ADC =1.890 × 10-3 mm2/s (0.871,92.7％,80.0％);and D =0.648 × 10-3mm2/s(0.740,70.0％,84.1％).Conclusion IVIM is useful to distinguish metastatic from nonmetastatic lymph nodes in lung cancer.The ADC and the D values are significant higher in metastatic lymph nodes,which more sensitive than the other parameters(D *,f,and short axis diameter).As a result,IVIM can be used in the N-stage diagnosis of lung cancer.