| Part One Clinical value of Advanced Virtual Monoenergetic technique on dual-source CT in Adrenal nodular lesions visualizationObjective: To compare the an advanced virtual monoenergetic technique(Mono+) and the first generation of virtual monoenergetic technique(Monoenergertic) on dual source CT in Adrenal nodular lesions visualization.Materials and methods: 102 patients with adrenal nodular lesions(including 22 cases of nodular hyperplasia and 80 cases of adenoma) underwent dual-energy CT scans(100k V/Sn140 k V). The images were post-processed both by Monoenergetic and Mono+. Images calculated at 40 ke V to 150 ke V with a 10 ke V step using Monoenergetic were included in Group A, and images calculated using Mono+ were included in Group B. CT values of lesions and normal adrenal gland, noise of lesions and normal adrenal gland, the Signal Noise Ratio(SNR) and the Contrast to Noise Ratio(CNR) and subjective score were compared between two groups at different ke Vs. Mean SNR、CNR、CT、SD values and subjective score of every ke V were also compared between two groups. Optimal ke V was chosen according to the average of SNR, CNR and subjective score in group B.Results:(1)The SNR of group B was significantly higher than group A statistical at every ke V in arterial and portal phase(p<0.05),except at 80 ke V.(2)The CNR of group A was significantly higher than group B statistical at 120-150 ke V in arterial phase(p<0.05), but not at other ke V and in portal phase.(3)The CT value of group B was significantly higher than group A statistical at 40-60 ke V in both phases(p<0.05).(4)The noise of group A was significantly higher at every ke V in both phases(p<0.05), except at 70-90 ke V.(5)The mean SNR and CNR of group B were both significantly higher in arterial phase(p<0.05) as well as mean SNR in portal phase. But the difference of mean CNR in portal phase was not statistical significant(p>0.05), as well as the mean CT value in both phase. The mean noise and of group B was significantly lower(p<0.05).(6)The subjective score of group B was significantly higher at every ke V(p<0.05), except 70-90 ke V, in both phases.(7)Moreover the SNR and CNR of group B was best at 40 ke V in both arterial and portal phase.Conclusions: Compare with Monoenergetic, Mono+ technique reduces image noise,while keeping CT values same. Thus we believe Mono+could provide better image quality, especially at lower ke V. In addition, the optimal ke V of Mono+ was 40 ke V in both phases.Part two Differentiation of adrenal nodular hyperplasia and lipid-poor adenoma by advance virtual monoenergetic technique on dual-source CTObjective: This study is to explore the feasibility of using an advanced virtual monoenergetic technique(Mono+) based on dual energy parameters to differentiate adrenal nodular hyperplasia and lipid-poor adenoma, and evaluate the clinical value of iodine concentration and the spectrum curves in recognizing adrenal nodular hyperplasia and lipid-poor adenoma.Materials and methods: The clinical manifestations and CT images of 49 patients with adrenal lesions were reviewed retrospectively, including 22 adrenal nodular hyperplasia cases and 26 lipid-poor adenomas cases. All patients had underwent dual-energy scans with dual-source CT(Definition Flash, Siemens Healthcare, Forchiheim).(1)An advanced virtual monoenergetic post processing application was used to obtain a series of monoenergetic images of 40~150ke V. Images at 40 ke V were analyzed by two experienced radiologist together, including position, shape, size, density, enhanced degree, and capsule.(2)The CT values of lesions on different energy level were measured. The difference of the spectrum curve between adrenal nodular hyperplasia and lipid-poor adenoma were analyzed.(3) Used dual energy post processing application ”Liver VNC” to obtain iodine map from two enhanced phases(arterial phase and portal phase respectively), the dual energy parameters including iodine concentration(IC) and normalized iodine concentration(NIC) were calculated and compared between two groups.(4)Used ROC curve to evaluate enhanced degree and IC/NIC in portal phase in differentiating adrenal nodular hyperplasia and lipid-poor adenoma.Results:(1)14 cases of nodular hyperplasia group were on the left side, while 8 cases on the right side. 18 cases of lipid-poor adenomas group were on the left side, while 8 cases on the right side. The shape of two groups were circular. The mean sizes of nodular hyperplasia group and lipid-poor adenomas group were(0.87±0.14) cm,(1.4±0.48) cm,with significant difference(p=0.048). All cases of hyperplasia group didn’t have capsules, while 21 cases of lipid-poor adenomas group did. The mean CT value for adrenal hyperplasia was(30±6.04) Hu, and(27±12.56) Hu for lipid-poor adenomas, without significant difference(p>0.05). In arterial phase, the mean relative and absolute enhancement values of both group were(0.85±0.08),(0.9±0.28);(163.94±15.45) Hu,(177.3±63.89)Hu, without significant difference(p>0.05). In portal phase, the mean relative enhancement values of both group were(1.02±0.21),( 0.88 ± 0.17), with significant difference(p=0.011). And the mean absolute enhancement values of both group were(201.10±39.43)Hu,(154.38±27.78)Hu, with significant difference(p=0.000).(2)The spectrum curve of the adrenal nodular hyperplasia and lipid-poor adenomas both declined from 40 ke V to 190 ke V, and the adrenal hyperplasia curve was above the adenomas curve in portal phase on all energy levels(p=0.001).(3)The IC and NIC of adrenal nodular hyperplasia group in portal phase were higher than lipid-poor adenoma group with significant difference(p<0.05).(4)ROC curve showed that the NIC of portal phase had biggest area(0.841) under the curve than that others’, and the threshold was 0.51,while sensitivity was 0.818, specificity was 0.769.Conclusions: The size, enhanced degree in portal venous phase, and capsule could provide the basis to differentiate adrenal nodular hyperplasia and lipid-poor adenoma. Spectrum curve IC from dual-source dual energy scans can help differentiate the two groups, and provide a new perspective in diagnosis. |
PDF Full Text Request