Clinical Study Of DSCT Perfusion Imaging And Dual Energy Imaging In Neck Lymph Node Lesions

Part one:Clinical Study of DSCT perfusion imaging in neck lymph node lesionsObjectiveTo study the CT imaging features of various lymph nodes in the neck by using CT perfusion parameters and morphological indexs, and to explore their values in the differential diagnosis.MethodDynamic enhanced DSCT scanning were performed in80patients with neoplasm in neck space from May2011to March2012,51Patients(51lymph nodes) had complete surgery and pathological evidence. The TDC and perfusion parameters(BF, BV, PBV, PBV, TTP, PE and REV) of51lymph nodes were recorded and analyzed statistically. Measured the morphological data (longitudinal diameter、transverse diametet、boundary、necrosis、calcification and enhancement degree)through studying the routine enhancement images and MPR images. Analyze blood flow modes of51 lymph nodes according to BF. Discern the51lymph nodes as benign and malignant by pathological evidence, and analyzed statistically.Compared the TDC data and perfusion parameters of two groups using two independent samples of nonparametric tests.Discerned as three groups (lymphoma, thyroid carcinoma, squamous carcinoma) by pathological evidence.Analysed the three groups by non-parametric test for multiple independent samples.Analysed the morph parameters and blood flow modes using x2-test.P<0.05was significantly different standards.Result(1) Pathological results:14objectives in benign group, including8lymph node reactive hyperplasias,6lymphoid tuberculosis.37objectives in malignant group, including13lymphoma (HL3cases, NHL10cases),5thyroid carcinoma metastases and19squamous carcinoma metastases.(2) Perfusion Parameters and analyse:the BV value of the malignant:116.28±65.24(ml/1000ml) and Per value:65.48±20.60(0.5ml·100ml-1·min-1) were higher than the benign and significant difference existed between the malignant lymph nodes and the benign lymph nodes (p<0.05) The BF value and BV value of the thyroid carcinoma metastases were statistically higher than those of lymphoma and squamous carcinoma metastases(P<0.05).There were no significant difference of the perfusion parameters between lymphoma and squamous carcinoma metastases. There were no significant difference of the perfusion parameters between lymph node reactive hyperplasias and lymphoid tuberculosis.(3) The TDC appearance:The TDC of CT perfusion imaging could be classified into4types. The TDC of the benign (6/14) presented the type with low level curve, The TDC of the malignant lymphomas (8/13) showed low level curve, The TDC of the thyroid carcinoma metastases (4/5) presented the type with rapid ascending and rapid descending curve.The TDC of squamous carcinoma metastases (8/19) show the rapid descending and slow descending curve.(4) The TDC parameters and comparing:the PE value of the benign:87.91±15.64HU and the TTP value of the benign:41.21±4.79s were higher or longer than the malignant:82.60±29.83HU,24.11±4.31s, and significant difference existed (P<0.05). The REV value of the malignant higher than the bengin, but they had no statistically difference (P>0.05).The PE value of the thyroid carcinoma metastases (129.19±62.94HU) statistically higher than the value of lymphoma (67.67±6.47HU) and squamous carcinoma metastases (80.57±10.15HU), the REV value of the thyroid carcinoma metastases(88.48±59.94HU) statistically higher than the value of lymphoma (23.63±8.04HU) and squamous carcinoma metastases (34.88±9.77HU)(P<0.05).There were no significant differences of the TDC parameters between lymphoma and squamous carcinoma metastases. There were no significant differences of the TDC parameters between lymph node reactive hyperplasias and lymphoid tuberculosis.(5)The margin and interior necrosis of lymph nodes had statistical difference between the benign and the malignant (P<0.05). The margin、interior necrosis、calcification and blood flow mode of lymph nodes had statistical difference between the five lesions of lymph nodes (lymph node reactive hyperplasias, lymphoid tuberculosis, lymphoma, thyroid carcinoma metastases and squamous carcinoma metastases)(P<0.05).Conclusion(1) CT perfusion imaging is a functinal imaging methods with noninvasive evaluation of tissue perfusion and can quantitative analyze the different pathological types of neck lymph node lesions.The BV and Per value of the malignant statistically higher than those of the benign.The TTP value of the malignant statistically shorter than the benign:The PE value of the malignant statistically higher than the benign.The differences were statistically significant.These parameters had certain values in differential diagnosis of the neck lymph node lesions.(2) The BF、BV、PE and REV value of the thyroid carcinoma metastases statistically higher than the value of lymphoma and squamous carcinoma metastases. There was no significant differential diagnosis between lymphoma and squamous carcinoma metastases in perfusion parameters.(3) There was no significant differential diagnosis between lymph node reactive hyperplasias and lymphoid tuberculosis in perfusion parameters.(4) The TDC of the benign presented the type with slowly ascending and low level curve. The TDC of the malignant lymphomas showed low level curve. The TDC of the thyroid carcinoma metastases presented the type with rapid ascending and rapid descending curve. The TDC of squamous carcinoma metastases showed the rapid descending and slow descending curve.(5) The margin and interior necrosis of lymph nodes could help the differential diagnosis of lymph nodes lesions.(6) The main blood flow mode of lymphoma was central blood flow, thyroid carcinoma metastases and squamous carcinoma metastases were marginal blood flow in main. The main blood flow mode of lymphoid tuberculosis was marginal blood flow and the lymph node reactive hyperplasias was central blood flow. Part two:Clinical Study of DSCT dual energy imaging in neck lymph nodes lesionsObjectivePerform dual energy delayed scan to various lymph nodes in the neck by using Siemens dual-source CT:1.To obtain iodine image and virtual unenhanced image, to study the correlation between iodine image and virtual unenhanced image and to explore whether virtual unenhanced image can replace routine plain or not.2. To observe the changes in trends of different pathological types of lymph node lesions in different X-ray energy and make differential diagnosis by analyzing the spectrum curve of the lymph nodes.MethodDual energy delayed DSCT scanning were performed in51patients with neoplasm in neck space from May2011to March2012,32Patients(32lymph nodes) had complete surgery and pathological evidence. Contrast enhanced scan was performed after plain.The dose of contrast agent was40ml/per unit of body surface area,350mgI/ml,injective rate2.0ml/s.The unnormal lymph nodes found during plain were performed delayed scan using DSCT with dual energy mode5mins later after the injection.Transfer the two groups dual energy data into Dual-Energy software of the workstation,choose Liver VNC mode to obtain the iodine image and virtual unenhanced image.Choose Monoenergetic mode to obtain images under different keV,40、50、60、70.80、90、100、110、120、130、140、150、160、170、180、190keV for instance. Measuring the CT values of the lymph nodes in all the obtained images we will find20data:lymph nodes conventional unenhanced CT value,enhanced CT value, virtual unenhanced CT value,Overlay value,single-energy spectrum of the CT value of40-190keV. Discern the32lymph nodes as benign and malignant by pathological evidence, and analyzed statistically.Used pearson test to do the correlation job.Compared the CT value of different energy spectrums of two groups using two independent samples of t-test.Discerned as two groups (lymphoma and squamous carcinoma) by pathological evidence.Analysed the two groups by t-test. Discerned as two groups (HL and NHL) by pathological evidence.Analysed the two groups by t-test. P<0.05was significantly different standards.Result(1) Pathological results:8objectives in benign group, including5lymph node reactive hyperplasias,3lymphoid tuberculosis.24objectives in malignant group, including13lymphoma (HL8cases, NHL5cases) and19squamous carcinoma metastases.(2) Comparative analyze between virtual unenhanced CT value and routain value of lymph node:Lymph node virtual unenhanced and routine unenhanced CT values showed good correlation (r=0.844, P<0.001). Iodine distribution within the lymph node image CT value and the enhanced value of lymph node (enhanced image lymph nodes on CT value-routine unenhanced CT value) also showed a good correlation (r=0.848, P<0.001). Lymph nodes in the virtual unenhanced CT value and iodine distribution of the total value of the image CT value and the value of CT image enhancement lymph nodes also showed a good correlation (r=0.882, P<0.001). Benign and malignant lymph nodes in the virtual unenhanced and routine unenhanced CT values showed good correlation (r=0.980, P<0.001and r=0.795, P<0.001), benign lymph node virtual unenhanced and conventional plain of CT value of the correlation coefficient is higher than the malignant lymph nodes.(3) The analysis results of the identification of lymph nodes in benign and malignant by DSCT spectrum:The differences in the CT values of benign lymph nodes and malignant lymph nodes under70and80keV were statistically significant (t=2.346, P =0.026and t=2.099, P=0.044). Hodgkin lymphoma (HL) and non-Hodgkin’s lymphoma (NHL) in40-80keV single section CT value differences were statistically significant (P<0.05), in the90-190keV, single section CT values were not statistically different (P≥0.05). On each section of the single energy-Hodgkin’s lymphoma (HL), CT values were higher than non-Hodgkin’s lymphoma (NHL). Lymphoma and squamous cell carcinoma metastatic lymph nodes in the50-140keV single-section CT value differences were statistically significant (P<0.05),40and150-190keV, single-section CT values were not statistically different(P>0.05). Squamous cell carcinoma and metastatic lymph nodes in CT values were higher than in each single-energy section on lymphoma.Conclusion(1) The virtual unenhanced and routine unenhanced CT value of lymph nodes have a good correlation and virtual unenhanced scanning is expected to replace the real plain to reduce the patient’s radiation dose.(2) The dual-energy spectrum analysis can provide some valuable information on the identification of benign and malignant lymphadenopathy. Different pathological types of lymph node metastases have different spectrum curves. The measurement of different single-energy diagram corresponding to the CT value has the potential value to distinguish the different pathological types of lymph node lesions.