| Background and objective: Patients of malignant tumors need inspection methods of covering the whole body to determine TNM stage of the tumors for clinical treatment, prognosis and evaluation of treatment. Methods of covering the whole body are more and more important. Now they are commonly used in systemic clinical assessment, including CT,SPECT,MRI,PET-CT,and so on. CT and SPECT are harmful to the human body, and they are not suitable for detection of short-term and means of review. Recently, PET-CT is an important way of covering the whole body, but it is very expensive and not popular. MRI has excellent soft tissue contrast and is suitable for tumor imaging. But time of inspection is too long and restriction of coils, so MRI scan of whole body need multiple scans. In recent years, with the development of MRI software and hardware, fast imaging sequences and parallel acquisition techniques develop and MRI scan of whole body is possible. WB-DWI imaging technique uses STIR-DWI-EPI sequence and determine the change of organizational structure according to diffusion of water molecules within the organization. Because the most common systemic metastases are lymph nodes, liver and bones, purpose of this paper is to explore the clinical value in the lymph-node ,live and bones metastasis of malignant tumors in the whole body diffusion weighted imaging and ADC value in the identification between metastatic lesions and benign lesions.Content: Fifty-eight patients with the whole body diffusion weighted imaging are collected from 2009-05 to 2009-12 in our hospital for the study, including 26 volunteers and 32 patients with malignant tumors (all have pathological findings).Lymph node metastasis, liver metastasis and bone metastasis of thirty-two cases are diagnosed by biopsy, PET-CT (all cases have PET-CT examination) or more CT, MRI being followed up for changes in lesions size (the time interval of one month).The clinical diagnosis of lymph node metastasis, liver metastasis and bone metastasis are contrasted with lymph node metastasis, liver metastasis and bone metastasis in WB-DWI imaging.Methods: GE HD1.5T are used, body coil is used, Signal acquisition uses the built-in magnet body coil, STIR-DWI-EPI sequence is used and the whole body diffusion weighted imaging is scanned in the free breathing condition. Scan range is from the head to the knee, Scanned four times, there are overlaps of three levels between each section, supine, feet first, laser-line is located in the glabellum. Then the original images are processed on the workstation (AW4.3), the Add / Sub software is used and sections are seamlessly superimposed. The 3D-MIP reconstruction and black and white reversal technology are used. Lesions are displayed by three-dimension, the original cross-sectional images are used, suspicious lesions are located and measured the ADC value by Functool software. According to ADC value and the signal characteristics, the position and number of lymph node metastasis, liver metastasis and bone metastasis are determined. Normal lymph nodes of twenty-six healthy volunteers are investigated on the WB-DWI imaging and the ADC value of lymph nodes are measured, then ADC value of a certain number of normal bone and liver tissue are measured.Lymph node metastasis, liver metastasis and bone metastasis of 32 cases of malignant tumors are observed on WB-DWI imaging, and the ADC values of metastatic lesions measured. Then lymph node metastasis, liver metastasis and bone metastasis on WB-DWI imaging are compared with the actual clinical diagnosis of lymph node metastasis, bone metastasis and liver metastasis. The number of true positive, false positive , false negative and accuracy rate of lymph node metastasis, bone metastasis and liver metastasis are computed. Locations of lymph node metastasis are divided into eight regions, including cervical part, both sides of the axillary fossa, clavicular region, mediastinum, hilum of lung, peritoneal cavity, retroperitoneal area, cavitas pelvis (including the groin area). Lymph node metastasis are divided into four groups according to short diameter of lymph nodes(short diameter:≤1.0cm,1.0<~<1.5cm,1.5≤~<2.0cm,≥2.0cm). Accuracy rate is calculated in various regions and different shirt diameter groups of lymph node metastasis. The skeletal system is divided into the skull, ribs, sternoclavicular ,spine, pelvis, limbs. Accuracy rate in various regions of bone metastasis are calculated. Finally the ADC values of lymph node metastasis, liver metastasis and bone metastasis are compared with the ADC value of normal lymph nodes, liver and bone, then quantitative data group t-test design and single factor analysis of variance are applied through SAS 9.13 statistical software.Results: In the WB-DWI imaging, the signal of surrounding tissues of the lesions is inhibited and metastatic lesions are clearly displayed. The ability to identify metastasis can satisfy clinical demand. Accuracy rate of lymph node metastasis, liver metastasis, bone metastasis reaches to 94.4%,90.5%,85.6%.The accuracy rate of lymph node metastasis (short diamete≥1.5cm) reach to 100% on the WB-DWI imaging. The lowest accuracy rate of lymph node metastasis (short diameter≤1.0cm) reaches to 50% on the retroperitoneal region and the lowest accuracy rate of lymph node metastasis (1.00.05).Conclusions: The whole body diffusion weighted imaging in the display of lymph node metastasis, liver metastasis and bone metastasis has some advantages. The accuracy rate is very high and the ability to identify metastasis can satisfy clinical demand. It provides a new means of image for the clinical TNM staging of the tumor. In particular, diagnosis of systemic lymph node metastasis has obvious advantage. In addition, the ADC value is quantitative value and it provides great value in the determination of tumor metastasis. |
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