Multi Slice Spiral CT Pulmonary Angiography in Dynamic Pitch Mode using Volume Helical Shuttle Technology for the Diagnosis of Pulmonary Embolism

Introduction : Multi slice Computed Tomography Pulmonary Angiography (CTPA) in dynamic pitch (Volume Helical Shuttle-VHS) mode is an evolving method to visualize pulmonary arteries including the peripheral pulmonary vasculature. The purpose of this study is to evaluate CT Pulmonary Angiography in dynamic pitch mode (Volume Helical Shuttle) for pulmonary embolism in comparison with standard pitch mode. Methods : We have done a multicentric analytical comparison study with study group involving patients undergone CTPA in dynamic pitch mode-Volume Helical Shuttle (VHS) and comparison group involving patients undergone CTPA in standard pitch mode. Results : Optimal contrast enhancement phase of the pulmonary artery in the study group in Phase I to III were 22.6%, 43.4% and 34%. The best phases were the last two phases in our study. Study Group main pulmonary artery mean signal intensity is 423.83±75.94 HU and comparison groups mean signal intensity is 361.74±98.28HU (P value = 0.039). The percentages of analyzable segmental arteries were 91.6% in study group and 87.3% in comparison group (P value-0.008). The percentages of analyzable sub segmental arteries were 89.5% in study group and 84% in comparison group (P value-0.004). The study group shows less percentage of motion artefacts and higher image quality than the comparison group, however it was not statistically significant (P value >0.05). Conclusions : Multislice CTPA in dynamic pitch mode using Volume Helical Shuttle (VHS) technology increase the ability to obtain the Optimal contrast enhancement in pulmonary arteries, improves the overall image quality, obviate the need for breath holding.

Dynamic multi-detector computer tomography with volume helical shuttle technique for diagnosis of congenital heart disease with tracheomalacia in children / 第二军医大学学报

Objective To explore the diagnostic value of dynamic multi-detector computer tomography (MDCT) with volume helical shuttle (VHS) technique in children with congenital heart disease (CHD) combined with tracheomalacia. Methods We retrospectively analyzed the imaging and clinical data of 26 patients (16 males, 10 females) with CHD who underwent both MDCT with VHS technique and fiber bronchoscope between Oct 2014 and Aug. 2016. According to the results of fiber bronchoscope, the patients were divided into tracheomalacia (n = 7) and non­tracheomalacia (n=19) groups. The intracardiac structures and the anatomy of the great arteries were demonstrated by maximum intensity projection (MIP) and volume render (VR) reconstruction. The patterns of the tracheobronchial tree were demonstrated using minimum intensity projection (MinIP) reconstruction. The Mimics 17. 0 software was employed to automatically segment the CT images of different respiratory phases of each patient and to measure the cross sectional area of the airway. According to the golden-standard of fiber bronchoscopic findings and operative results, we calculated the diagnostic accuracy of VHS for CHD and the sensitivity, specificity and accuracy for tracheomalacia Results Compared with nontracheomalacia group, the patients in tracheomalacia group showed significantly greater cross-sectional area change of the trachea (34.23%-74. 95% vs 13. 73%-78. 87%, P= 0. 02). The diagnostic sensitivity, specificity and accuracy of VHS technique for tracheomalacia were 85.71%(6/7), 84. 21%(16/19) and 84. 62%(22/26), respectively. VHS showed accuracies of 100%(12/12) and 91. 67%(11/12) in diagnosing extracardiac and intracardiac defects, respectively. Conclusion Dynamic MDCT with VHS technique can provide a one-step diagnosis of tracheomalacia with CHI) in children.

Diagnostic value of spectrum CT volume helical shuttle technology in detection of pulmonary arteriovenous malformations / 实用放射学杂志

Objective To access the diagnostic value of volume helical shuttle (VHS)technology of spectrum CT in detection of the pulmonary arteriovenous malformations (PAVM).Methods Thirteen patients with PAVM confirmed by surgery and clinical data underwent CT pulmonary artery angiography with VHS technology,which were regarded as group A.The consecutive images at four different phases were gotten Meanwhile,other thirty patients underwent conventional CT pulmonary artery angiography using bolus tracking scan,regarded as Group B.The enhancement degrees of the pulmonary trunk were measured,and the image quality was also subjectively assessed by two radiologists separately,which were compared between two groups.Results In group A,the proportion of optimal phase in each of the four phases was 15.38% (2/13),46.15% (6/13),30.77% (4/13)and 7.7% (1/13),respectively.The mean CT value in pulmonary trunk was (329.21±41.63)HU in group A and (281.74±49.83)HU in group B,exhibiting no difference (P =0.989). The percentage of enhancement degree of pulmonary trunk more than 300 HU in group A was more than that in group B (P=0.000).However, the image quality of the main pulmonary artery,lobar pulmonary artery or segmental pulmonary artery was not significantly different between two groups (P >0.05).There were no statistically differences in mean DLP between group A of (715.54±195.37)mGy/cm and group B of (558.36±186.81)mGy/cm (t=3.737,P=0.068).Conclusion Spectrum CT VHS with higher image quality and enhancement degree is superior to conventional CT scan,which can be used to reduce the influence of individual circulation difference on image quality.