MSCT Diagnosis Of Small Adrenal Nodules In Primary Hyperaldosteronism

Part1:CT Measurement of Normal Aadrenal Gland VolumeObjective:To measure the volume of normal bilateral adrenal glands on CT images by two means of manual segmentation depicting the region of interest and semi-automated volume segmentation respectively, to compare and evaluate the reproductivity of the two measurements.Materials and Methods:Using two methods of manual segmentation depicting the region of interest and semi-automated volume segmentation to measure the volume of60adrenal glands in30lung cancer patients with normal adrenal function, no adrenal nodules and whose morphology of bilateral adrenal without increasing followed up for over6months. The difference of the two measurement was analysed by Pearson correlation analysis, and the reported results in literature served as a reference value to determine the accuracy of the two measurement.Results:The left adrenal gland volume was (4.81±1.56) cm3, and the right adrenal gland volume (3.80±0.97)cm3by manual decipting the region of interest; the left adrenal gland volume was (10.30±1.44) cm3, and the right adrenal gland volume (8.51±1.64) cm3by semi-automated volume segmentation method. The two methods of adrenal gland volume measurement significantly different (P>0.05).Summary:The normal adrenal gland volume obtained by the semi-automated volume segmentation method was significantly greater than that of the manual depicting the region of interest measurements, the measurement data of the latter is closer to the reference value.Part2:Value of MSCT Multi-planar Reformat in Diagnosis of Small Adrenal Nodules in Primary AldosteronismObjective:To compare the accuracy of MSCT multi-planar reformat images and conventional axial images in detecting small adrenal nodules in primary hyperaldosteronism and to investigate the diagnostic value of multi-planar reformat in small adrenal nodules.Materials and Methods:There were30cases of primary hyperaldosteronism patients with a adrenal nodule which the maximum diameter was less than1.5cm enrolled with complete clinical and pathological data. Both enenhanced CT and multiphasic contrast enhanced CT were perfomed. The volume data of lmin post contrast series were reconstructed in1.25cm thickness slices, then multi-planar reformat were carried out on an off-line workstation. The two ways of direct observation of the axial images and multi-planar reformat images to diagnose adrenal nodules.Results:The sensitivity, specificity, accuracy, positive predictive value and negative predictive values of small adrenal nodules diagnosed by axial images were93.3%、80.0%、86.7%、82.4%and75.0%, and by multi-planar reformat images were96.7%、100%、98.3%、100%and96.8%, respectively.Summary:The diagnosis the small adrenal nodules on MSCT by means of multi-planar reformat is more accurate than the diagnosis by axial images.Part3:CT Differential Diagnosis of Adrenal Nodules in Primary HyperaldosteronismObjective:To evaluate the differential diagnostic value of CT in characterization of adrenal nodules in primary hyperaldosteronism.Materials and Methods:CT features of190adrenal nodules in184surgically proved primary hyperaldosteronism were reviewed and the thickness of non-lesion limps were measured, the CT findings between group of aldosterone-producing adenoma and idiopathic hyperplasia were analyzed and compared with each other.Results:There were statistically difference in maximal diameter and the existence of peripheral ring-shaped enhancement between aldosterone-producing adenoma and idiopathic hyperplasia (P<0.05), however, there was no discrepancy on other feature included number of nodules per patient, the location, CT attenuation and absolutely washout ratios in3min,5min and7min. Summary:The maximal diameter and the existence of marginal enhancement of the adrenal nodular are the CT features in the discrimination between aldosterone-producing adenomas and idiopathic hyperplasias.Conclusion:1. The semi-automated volume segmentation method to obtain the normal adrenal gland volume was significantly greater than the manual depicting the region of interest measurements, the measurement data of the latter method is closer to the reference value.2. MSCT combined with MPR technology has a high diagnostic value in the diagnosis of small adrenal nodules.3. There are considerable overlapping in CT features between aldosterone-producing adenomas and idiopathic hyperplasias, however, the maximal diameter and the existence of marginal enhancement of the nodular are the main characteristics in the discrimination between the two groups.