Lympatic Involvement Of Peripheral Lung Cancer Correlated To The 16-slice Spiral CT Perfusion And Histological Microvessel Density

Objective: To evaluate the clinical value of CT perfusion imaging for providing quantitative information about angiogenesis in patients with lung carcinoma. To investigate the correlations of lymphatic involvement and CT perfusion of peripheral pulmonary carcinoma as well as histological micro vessel density (MVD) of the tumors.Materials and methods:1. Between March 2006 and September 2007,53 consecutive patients (36 men, 17 women; age range,31～70 years; mean age, 54.3years; size range, 1.8 -6.4 cm; mean size of the lesions, 3.7cm.) with definite masses who were detected by Chest X-ray or plain CT scanning were chosen to perform 16-slice spiral CT perfusion scanning. None of the patients had been treated with anticancer drugs before CT perfusion scanning and surgery .All the patients received the CT perfusion scanning with one to two week before surgery. And all lesions were confirmed by pathologic examination after surgical resection. The clinical document (including operating record, histological report, and situations of lymphatic involvement) is integrated. All patients with pulmonary carcinoma were classified into two group according to the pathologic reports: tumor with mediastinum lymphatic involvement and without mediastinum lymphatic involvement. 2. All patients first underwent unenhanced CT scanning with SIMENSE Sensation 16 CT scanner. Then four adjacent sections locating the center of the lesion were chosen to be the target sections and CT perfusion scanning in first pass phase(FPP) was performed by the "Toggling-Table" technology. The section thickness was 3mm for lesions less than 3cm and 6mm for lesions largerer than 3cm.For perfusion scanning, following parameters: 120 KV, 80mA, cine full, 0.5second scan time per circle, non-ionic agent (350 mg I/ml) 40 ml, infusion rate of 4.0ml /sec, scanning started at 6 seconds after the beginning of injection and acquisition time of 30 seconds were used.3. All perfusion images were transferred into Volume Wizard workstation. The time-density curves (TDC) were creased from regions of interest drawn over the tumor and aorta by the DynEva software in the workstation, and calculate CTP enhance index of the ROI: the peak height (PH) of mass, the ratio of the peak height of mass to the peak height of aorta (M/A), then the perfusion value(PV) was calculated using the maximum-slope method.4. Pathologic types of specimens were determined by hematoxylin and eosin (HE) staining. The expression of CD34 in 53 cases were detected by LSAB immunohistochemistry staining, then the MVD counting by Weidner method was performed.5. Statistical Analysis: The statistical analysises were performed with spss13.0 software. Two-sample t test was used (if necessary, with correction for unequal variance with the two-sample t' test) to test the difference between CT perfusion enhancer index and MVD . A Pearson correlation coefficient test was used to compare the CT perfusion enhancement index and MVD. The receiver operating characteristic (ROC) curve analysis was used to estimate the efficiency of CTP enhance index (PV)as well as histological parameter (MVD) to predict the lymphatic system statues ,and to select the cutoff points for dichotomization of CTP enhance index(PV) and histological parameter(MVD) for the criterion as the greatest overall accuracy.Results1. According to lymph node diameter greater than 10mm for metastasis, the sensitivity, specificity and the accuracy as by contrast- enhanced CT scan was 84.6%,70.4% and77.4%.2. Tumors with mediastinum lymphatic involvement had significantly higher value of MVD than those without medistinum lymphatic involvement (64.69±16.34, 42.67±16.78,P<0.001),3. The CTP enhance index (PH,M/A,PV) of lung cancer correlated positively with the MVD ,respectively ,The highest correlation coefficient was between the PV and MVD(r=0.716, P <0.01).4. Tumors with mediastinum lymphatic involvement had significantly higher value of The CTP enhance index (PV,PH,M/A)than those without medistinum lymphatic involvement (P <0.01), No significant differences in the diameter of primary tumor was found in two groups(p>0.05).5. With ROC curve analysis, MVD and PV had high value in estimate and predict lymph node involvement. If MVD 52 was taken as a threshold to predict lymphatic involvement , sensitivity,specificity,accuracy as(80.8%, 81.5%, 81.1%); If PV 1.52 was taken as a threshold to predict lymphatic involvement, sensitivity,specificity,accuracy as(84.6%, 85.2%, 84.9%).ConclusionThe CT perfusion enhance index can reflect lung carcinoma angiogenesis activity and provide its quantitative perfusion information exactly; The CT perfusion enhance index PV and histological MVD had good correlation with lymphatic involvement of primary carcinoma, and could be used to predict lymphatic involvement. This method is superior to histopathological method, and might helpful in guide clinical treat and assess prognosis.