| Objective To investigate the diagnosis and differential diagnosis value of dual-phase enhanced multi-slice spiral CT (MSCT) combined with color doppler flow image (CDFI) in the benign and malignant parotid gland tumor, especially to diagnostic the benign pleomorphic adenoma and the malignant tumor of lack of malignant CT features.The gain was to improve the diagnostic accuracy of parotid gland tumor before surgery, and provide a more reliable basis for clinical treatment.Materials and methods To analyze the imaging of dual-phase enhanced MSCT (30s,120s) and CDFI (resistance index RI) in the 12 benign pleomorphic adenoma,10 Warthin's tumor,13 malignant tumor of lack of malignant CT features that were confirmed by pathology,on April 2008-August 2010 in affiliated tumor hospital, Guangxi Medical University, all patients were taken dual-phase enhanced MSCT and CDFI examination in three days before surgery, in order to avoid CT contrast agent affect to analyze the blood of the parotid gland tumor when were taken CDFI examination, firstly, to take CDFI examination, then take double-phase enhanced MSCT. MSCT parameters:35 cases were taken unenhanced and enhanced scan by GE light speed Ultra 8-slice spiral CT machine. unenhanced parameter:tube voltage 120KV, tube current 200mA, slice thickness 5mm, interval 0, matrix 512×512. Enhanced scan Parameters:injected the non-ionic contrast agent iohexol 300mg/ml, dose of 100ml, speed of 2.0ml/s into the median cubical vein by the high pressure syringe. Arterial phase and delayed phase were 30s,120s after injection. Scan range from basis cranii to supraclavicular fossa of the neck, but the suspected malignant parotid gland including full neck in order to observe the cervical lymph node metastases. Image evaluation:①on the location (or intent range):②external carotid artery and/or mandibular was voilated or embeded;③low density distribution of the lesions (central distribution or marginal distribution);④dual-phase enhanced characteristics (washout or delayed enhancement). CDFI examination:all cases were used a linear probe by GE ultrasound and frequency 5-10MHz, in order to gain maximum sensitivity and avoid the noise, pulse repetition frequency (Pulse-Repetition Frequency PRF) 500-1000 Hz. All patients took supine position and the cushions under the neck, head turned contralateral to stretch the neck in patients which fully exposed the checking area, and then directly scanning the parotid region by scanning of vertical and horizontal multi-slice and noting to compared with the contralateral parotid gland. Firstly, taking two-dimensional ultrasound to definite the location of parotid gland tumor, and then observe the blood of tumor by CDFI. To select the primary vessels branch of parotid tumor,to chose the stable and bright blood flow for Pulse Doppler sampling, regulating the sample volume was 1-3mm and the filter frequency was 100-125MHz, and corrected the angle<600 between the beam and the blood flow, measured RI after appeared the stable blood flow. To study the diagnostic value and limitation of dual-phase enhanced MSCT in parotid benign and malignant tumors, and to identify malignant parotid CDFI diagnosis of resistance index (RI) threshold, and to evaluate the means of combining the two imaging of parotid benign and malignant diagnosis and differential diagnosis. Pathological analysis:All specimens were stained with HE and were analyzed by the experts of pathology.Results①The CT value of enhanced dual-phase in Warthin's (P< 0.05) was different from malignant tumor and benign pleomorphic adenoma(p> 0.05),among which there were no statistical differences.②The sensitivity and the specificity of diagnosis in the parotid gland of the Warthin's tumor were 90% and 100% respectively by dual-phase enhanced multi-slice spiral CT,and the sensitivity and the specificity of diagnosis in the parotid gland of the pleomophic adenomas and the malignant tumor were 60.00%,65.21% and 46.15%,59.10% respectively; Taking into consideration RI≥0.77 as the threshold for diagnosis of the parotid gland of malignant tumor,the sensitivity and the specificity of diagnosis in malignat tumor were 92.30%, 83.33% respectively.③The sensitivity and the specificity of diagnosis in malignat tumor were 84.62%,100% respectively by the enhanced dual-phase MSCT with the CDFI.Conclusion Enhanced dual-phase MSCT has some limitations in diagnosis of parotid begign pleomorphic adenoma from parotid malignant tumor, combine with CDFI examination can make up for lack of the former and effectively improve the diagnosis accuracy of the parotid malignant tumors which lack in morphological characteristics of CT, help to choose the clinical treatment. |
PDF Full Text Request