| Background: Spleen is the biggest organ in reticulate endothelium system, which is an important immune organ and participates in mechanism of organism immunoregulation. The function of spleen is related to its morphous. In addition to liver disease, which can cause splenomegaly, other diseases such as infection, immune system diseases, circulatory system diseases, blood and haematopoiesis diseases, oncology diseases and connective tissue diseases, metabolic diseases and drug[1-2], which also can cause change of spleen volume and mostly cause increased volume of spleen. It is one of the indexes for diseases of liver and spleen by ways to evaluating if spleen volume is changed by clinical and imageology physician[3]. The present study only by percussion and palpation can not be sensitive to find all the cases of the spleen increase, therefore, measuring spleen volume is significant for diagnosis, treatment, prognosis, therapeutic effect assessment[4-15]. That ablated spleen lost considerable blood in operation and the change of circulatory condition during operation affect spleen volume. Some reports manifested that spleen volume is 25%~50%[16, 17] much bigger than that after operation. So volume of ablated spleen can not represent actual volume of living spleen. There is instructive significance for clinic work to assess and measure volume of living spleen relatively precisely.At present, there are many ways to measure volume of living spleen which including ultrasonic, CT, zeugmatography and radioisotope scanning[18-68], and ways of measurement are gradually improved. With the instrument design progresses, the major measurement for spleen volume is to apply multilayer spiral computed tomography (MSCT), the result of MSCT is to approach actual volume of spleen. But the cost of CT is relatively high and is accompanied with radiation, which can not be universal as ultrasonnd in conventional examination. When compared to CT, ultrasound is convenient, no radiation, utilized extensively and cheap prices. At present, spleen size is detected by ultrasonic through measuring thickness diameter of spleen, which is relatively crude and affected by morphous of spleen. So it is easily misdiagnosis. In clinic, it often occurred that spleen volume detected by ultrasonic is not consistent with symptom and laboratory examination, especially when spleen volume is on critical data. Nobody detected spleen volume by ultrasonnd before because this detection is limited to one-dimensional and two-dimensional image, while spleen is a stereoscopic organ and its detection can be realized by three- dimensional. According to above, we designed ultrasonic examination to detect area of cross section of minor axis from detection of major axis of adult spleen every interval 1cm. Then we apply computer software procedure to set up special model and insert areas of cross section of minor axis to this procedure. Finally volume of spleen can be calculated.Objective: To establish model of spleen volume detected by ultrasonic and use this method to research spleen volume of normal adults and hepatic cirrhosis patients.Methods: (1) Ultrasonic measurement: Since ultrasonic machine can only measure the one-dimensional and two-dimensional data, we must measure spleen through two axial directions in order to precisely determine certain location. First, we clearly scan area image of cross section of maximal macroaxis through porta lienis from spatium intercostale of left abdominal region. From this cross section, we can determine long diameter of spleen and thickness data of every indicated location. Thickness data of spleen is not used in designed model, but it is important to determine certain location of short anteroposterior diameter of every interval of 1cm for next step. From one extremity of spleen, following the spleen macroaxis, measure and record every thickness data of every interval of 1cm from vertical direction of spleen capsule. Second, from direction of minor axis that is vertical to macroaxis, we scan image of cross section of minor axis in certain location every interval of 1cm, which are mentioned just now. The thickness data is the key to find the indicated location of cross section of minor axis. On every cross section of minor axis, we trace area by trackball and insert the area data into a designed procedure. Finally the spleen volume can be calculated automatically. (2) Software design: indicated area of cross section of minor axis of spleen is measured by ultrasonic. And any measurement ways (including MSCT) can not measure all areas of the whole cross section of spleen. But area data obtained from the above methods can be used to estimate all area information because no evident changes will appear from the consecutive areas of cross section of minus axis of spleen. So we can estimate area information by ways of interpolation. We specifically apply cubic B-spline curve interpolation methods of univariate or bivariate. We designed the certain procedure demonstrated by one figure, which represented cubic B-spline curve interpolation methods. The X-axis of cubic B-spline curve represented distance from upper pole to anus perineum of spleen and the Y-axis of that represented area of cross section of minus axis of spleen. Then area data measured by ultrasonic was inserted in procedure and the spleen volume can be calculated automatically. Results measured by cubic B-spline curve interpolation methods of univariate or bivariate were showed by yellow and pink curve. (3) Results of spleen volume measured by ultrasonic were compared to those of spleen volume measured by CT, on the base of which we can initially estimate exactitude of this ultrasonic method. (4) To measure spleen volume of normal adults by this ultrasonic method and try to obtain normal amplitude of reference value of that. Then use this method to approach diagnosis criterion. (5) To measure spleen volume of hepatic cirrhosis patients after hepatitis by this ultrasonic method and initially estimate amplitude of reference data of that of these patients.Results: we will measure area of cross section of every interval of 1cm from direction of macroaxis of adults'spleen and insert area data into the procedure that is designed by computer software. Finally the spleen volume can be calculated automatically and we successfully set up the new model in which spleen volume can be measured by ultrasound. In cases of 20 patients, whose spleen volume were simultaneously measured by CT scan and ultrasound, the average of spleen volume measured by CT is (179.54±47.26)cm3 and the average of that measured by ultrasound is (170.62±43.83)cm3. There is no obviously significance between the results of these two ways (P>0.05). There is positive correlation between two methods (r=0.987). And in the group of 56 adults, the average of male spleen volume is (218.17±70.93)cm3,95% normal amplitude of reference value ( x±1.96s) of that is (79.14~357.19)cm3; the average of female spleen volume is (169.13±55.44)cm3, 95% normal amplitude of reference value ( x±1.96s) of that is (60.46~277.79)cm3; the average of all spleen volume in this group is (191.55±64.16)cm3,95% normal amplitude of reference value ( x±1.96s) of that is (65.79~317.3)cm3. The average of male spleen volume is higher than that of female spleen volume and there is obviously significance between them (P<0.05). In cases of 25 patients of hepatic cirrhosis after hepatitis, whose spleen were measured by ultrasound, the maximal volume is 1903.24cm3, and the minimum is 294.83cm3, the average is (858.37±459.62)cm3. There is obviously significance (P<0.05) between results of these patients and that of normal adults above (191.55±64.16)cm3.Conclusions: (1) In this research, we inserted data measured by ultrasound into designed procedure to estimate spleen volume and initially established special model applied ways of ultrasound. (2) There is no obviously significance between the results of spleen volume measured by CT or ultrasound and there is positive correlation between two methods (r=0.987). We identify that it is possibility to apply this ultrasonic method. And spleen volume measured in this ultrasonic method is approximated to actual spleen volume. So results measured by this method can be used to direct clinic treatment. (3) In the group of 56 adults, the average of male spleen volume is (218.17±70.93)cm3,the average of female spleen volume is (169.13±55.44)cm3, the average of male is more than that of female and there is obviously significance between them. (4) Because 95% normal amplitude of reference data of normal male and female adults are 357cm3 and 278cm3 respectively, 357cm3 can be used preliminary evaluation index to estimate if spleen volume is increased. (5) There is obviously significance between spleen volume of patients with hepatic cirrhosis after hepatitis and that of normal control groups. (6) For patients of hepatic cirrhosis after hepatitis, there is much difference in different cases.Significance: Since this research first set up this new model to measure spleen volume by ultrasonography that it is significant for clinical application. We preliminary assessed normal value criterion of spleen volume of normal adults and diagnosing criterion of splenomegaly, which provided evidences for clinical diagnosis. Another significance of this research is that we estimated therapeutic effect of the same case before and after treatment or in different stages of disease according to measurement of changes of spleen volume. For example, leukemia patients with splenomegaly, who were needed to accept chemotherapy regularly but could not accepted CT examination because of cost and irradiation, could be measured the spleen volume by this ultrasonography model established by us. Furthermore, their spleen volume measured by ultrasonography before and after treatment could be compared to other results such as laboratory examination, which would direct clinical diagnosis, treatment and evaluation of clinical effect. |
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