Development of Upright Computed Tomography With Area Detector for Whole-Body Scans: Phantom Study, Efficacy on Workflow, Effect of Gravity on Human Body, and Potential Clinical Impact.
- 作者列表："Jinzaki M","Yamada Y","Nagura T","Nakahara T","Yokoyama Y","Narita K","Ogihara N","Yamada M
OBJECTIVES:Multiple human systems are greatly affected by gravity, and many disease symptoms are altered by posture. However, the overall anatomical structure and pathophysiology of the human body while standing has not been thoroughly analyzed due to the limitations of various upright imaging modalities, such as low spatial resolution, low contrast resolution, limited scan range, or long examination time. Recently, we developed an upright computed tomography (CT), which enables whole-torso cross-sectional scanning with 3-dimensional acquisition within 15 seconds. The purpose of this study was to evaluate the performance, workflow efficacy, effects of gravity on a large circulation system and the pelvic floor, and potential clinical impact of upright CT. MATERIALS AND METHODS:We compared noise characteristics, spatial resolution, and CT numbers in a phantom between supine and upright CT. Thirty-two asymptomatic volunteers (48.4 ± 11.5 years) prospectively underwent both CT examinations with the same scanning protocols on the same day. We conducted a questionnaire survey among these volunteers who underwent the upright CT examination to determine their opinions regarding the stability of using the pole throughout the acquisition (closed question), as well as safety and comfortability throughout each examination (both used 5-point scales). The total access time (sum of entry time and exit time) and gravity effects on a large circulation system and the pelvic floor were evaluated using the Wilcoxon signed-rank test and the Mann-Whitney U test. For a large circulation system, the areas of the vena cava and aorta were evaluated at 3 points (superior vena cava or ascending aorta, at the level of the diaphragm, and inferior vena cava or abdominal aorta). For the pelvic floor, distances were evaluated from the bladder neck to the pubococcygeal line and the anorectal junction to the pubococcygeal line. We also examined the usefulness of the upright CT in patients with functional diseases of spondylolisthesis, pelvic floor prolapse, and inguinal hernia. RESULTS:Noise characteristics, spatial resolution, and CT numbers on upright CT were comparable to those of supine CT. In the volunteer study, all volunteers answered yes regarding the stability of using the pole, and most reported feeling safe (average rating of 4.2) and comfortable (average rating of 3.8) throughout the upright CT examination. The total access time for the upright CT was significantly reduced by 56% in comparison with that of supine CT (upright: 41 ± 9 seconds vs supine: 91 ± 15 seconds, P < 0.001). In the upright position, the area of superior vena cava was 80% smaller than that of the supine position (upright: 39.9 ± 17.4 mm vs supine: 195.4 ± 52.2 mm, P < 0.001), the area at the level of the diaphragm was similar (upright: 428.3 ± 87.9 mm vs supine: 426.1 ± 82.0 mm, P = 0.866), and the area of inferior vena cava was 37% larger (upright: 346.6 ± 96.9 mm vs supine: 252.5 ± 93.1 mm, P < 0.001), whereas the areas of aortas did not significantly differ among the 3 levels. The bladder neck and anorectal junction significantly descended (9.4 ± 6.0 mm and 8.0 ± 5.6 mm, respectively, both P < 0.001) in the standing position, relative to their levels in the supine position. This tendency of the bladder neck to descend was more prominent in women than in men (12.2 ± 5.2 mm in women vs 6.7 ± 5.6 mm in men, P = 0.006). In 3 patients, upright CT revealed lumbar foraminal stenosis, bladder prolapse, and inguinal hernia; moreover, it clarified the grade or clinical significance of the disease in a manner that was not apparent on conventional CT. CONCLUSIONS:Upright CT was comparable to supine CT in physical characteristics, and it significantly reduced the access time for examination. Upright CT was useful in clarifying the effect of gravity on the human body: gravity differentially affected the volume and shape of the vena cava, depending on body position. The pelvic floor descended significantly in the standing position, compared with its location in the supine position, and the descent of the bladder neck was more prominent in women than in men. Upright CT could potentially aid in objective diagnosis and determination of the grade or clinical significance of common functional diseases.
目的: 人体多个系统受到重力的极大影响，并且许多疾病症状会因姿势而改变。然而，由于各种直立成像方式的局限性，如空间分辨率低、对比度分辨率低、扫描范围有限或检查时间长等，对站立时人体的整体解剖结构和病理生理学还没有进行彻底的分析。最近，我们开发了一种直立的计算机断层扫描 (CT)，它能够在15秒内通过三维采集实现整个躯干横截面扫描。本研究的目的是评估性能，工作流程功效，重力对大循环系统和盆底的影响，以及直立CT的潜在临床影响。 材料和方法: 我们比较了仰卧和直立CT之间的噪声特征、空间分辨率和CT数字。32名无症状志愿者 (48.4 ± 11.5岁) 在同一天用相同的扫描方案前瞻性地接受了两次ct检查。我们对这些接受直立ct检查的志愿者进行了问卷调查，以确定他们对整个采集过程中使用电杆的稳定性的看法 (封闭式问题)，以及每次检查的安全性和舒适性 (均使用5分量表)。使用Wilcoxon符号秩检验和Mann-Whitney U检验评估总进入时间 (进入时间和退出时间的总和) 以及重力对大循环系统和骨盆底的影响。对于大循环系统，在3个点 (上腔静脉或升主动脉，在膈肌水平，下腔静脉或腹主动脉) 评估腔静脉和主动脉的区域。对于盆底，评估从膀胱颈到耻骨尾骨线和肛门直肠交界处到耻骨尾骨线的距离。我们还检查了直立式CT在腰椎滑脱、盆底脱垂和腹股沟疝功能性疾病患者中的应用。 结果: 直立CT的噪声特征、空间分辨率和CT数字与仰卧CT相当。在志愿者研究中，所有志愿者就使用电杆的稳定性回答是，并且大多数人报告在整个直立ct检查中感觉安全 (平均评分为4.2) 和舒适 (平均评分为3.8)。与仰卧位CT相比，直立位CT的总进入时间显著减少56% (直立位: 41 ± 9秒vs仰卧位: 91 ± 15秒，P <0.001)。直立时，上腔静脉面积比仰卧位小80% (直立: 39.9 ± 17.4毫米vs仰卧: 195.4 ± 52.2毫米，P <0.001)，膈肌水平面积相似 (直立: 428.3 ± 87.9毫米vs仰卧:426.1 ± 82.0毫米，P = 0.866)，下腔静脉面积大37% (直立: 346.6 ± 96.9毫米vs仰卧: 252.5 ± 93.1毫米，P <0.001)，而主动脉面积在3个级别之间没有显著差异。相对于仰卧位的水平，站立位的膀胱颈和肛门直肠连接部显著下降 (分别为9.4 ± 6.0毫米和8.0 ± 5.6毫米，均P <0.001)。女性的膀胱颈下降趋势比男性更明显 (女性为12.2 ± 5.2毫米，男性为6.7 ± 5.6毫米，P = 0.006)。在3例患者中，直立CT显示腰椎间孔狭窄，膀胱脱垂和腹股沟疝; 此外，它以常规CT不明显的方式阐明了疾病的分级或临床意义。 结论: 直立CT与仰卧位CT在身体特征上相当，并且显著减少了检查的进入时间。直立CT可用于阐明重力对人体的影响: 重力根据身体位置不同地影响腔静脉的体积和形状。与仰卧位相比，站立位的盆底明显下降，女性的膀胱颈下降比男性更为突出。直立CT可能有助于常见功能性疾病的客观诊断和分级或临床意义的确定。
METHODS:OBJECTIVES:The aim was to evaluate the image quality and sensitivity to artifacts of compressed sensing (CS) acceleration technique, applied to 3D or breath-hold sequences in different clinical applications from brain to knee. METHODS:CS with an acceleration from 30 to 60% and conventional MRI sequences were performed in 10 different applications in 107 patients, leading to 120 comparisons. Readers were blinded to the technique for quantitative (contrast-to-noise ratio or functional measurements for cardiac cine) and qualitative (image quality, artifacts, diagnostic findings, and preference) image analyses. RESULTS:No statistically significant difference in image quality or artifacts was found for each sequence except for the cardiac cine CS for one of both readers and for the wrist 3D proton density (PD)-weighted CS sequence which showed less motion artifacts due to the reduced acquisition time. The contrast-to-noise ratio was lower for the elbow CS sequence but not statistically different in all other applications. Diagnostic findings were similar between conventional and CS sequence for all the comparisons except for four cases where motion artifacts corrupted either the conventional or the CS sequence. CONCLUSIONS:The evaluated CS sequences are ready to be used in clinical daily practice except for the elbow application which requires a lower acceleration. The CS factor should be tuned for each organ and sequence to obtain good image quality. It leads to 30% to 60% acceleration in the applications evaluated in this study which has a significant impact on clinical workflow. KEY POINTS:• Clinical implementation of compressed sensing (CS) reduced scan times of at least 30% with only minor penalty in image quality and no change in diagnostic findings. • The CS acceleration factor has to be tuned separately for each organ and sequence to guarantee similar image quality than conventional acquisition. • At least 30% and up to 60% acceleration is feasible in specific sequences in clinical routine.
METHODS:BACKGROUND:The main surgical techniques for spontaneous basal ganglia hemorrhage include stereotactic aspiration, endoscopic aspiration, and craniotomy. However, credible evidence is still needed to validate the effect of these techniques. OBJECTIVE:To explore the long-term outcomes of the three surgical techniques in the treatment of spontaneous basal ganglia hemorrhage. METHODS:Five hundred and sixteen patients with spontaneous basal ganglia hemorrhage who received stereotactic aspiration, endoscopic aspiration, or craniotomy were reviewed retrospectively. Six-month mortality and the modified Rankin Scale score were the primary and secondary outcomes, respectively. A multivariate logistic regression model was used to assess the effects of different surgical techniques on patient outcomes. RESULTS:For the entire cohort, the 6-month mortality in the endoscopic aspiration group was significantly lower than that in the stereotactic aspiration group (odds ratio (OR) 4.280, 95% CI 2.186 to 8.380); the 6-month mortality in the endoscopic aspiration group was lower than that in the craniotomy group, but the difference was not significant (OR=1.930, 95% CI 0.835 to 4.465). A further subgroup analysis was stratified by hematoma volume. The mortality in the endoscopic aspiration group was significantly lower than in the stereotactic aspiration group in the medium (≥40-<80 mL) (OR=2.438, 95% CI 1.101 to 5.402) and large hematoma subgroup (≥80 mL) (OR=66.532, 95% CI 6.345 to 697.675). Compared with the endoscopic aspiration group, a trend towards increased mortality was observed in the large hematoma subgroup of the craniotomy group (OR=8.721, 95% CI 0.933 to 81.551). CONCLUSION:Endoscopic aspiration can decrease the 6-month mortality of spontaneous basal ganglia hemorrhage, especially in patients with a hematoma volume ≥40 mL.
METHODS:OBJECTIVE:The primary purpose of this study was to evaluate the effectiveness of a three-dimensional (3D) software tool (smart planes) for displaying fetal brain planes, and the secondary purpose was to evaluate its accuracy in performing automatic measurements. MATERIAL AND METHODS:This prospective study included singleton fetuses with a gestational age (GA) greater than 18 weeks. Transabdominal two-dimensional ultrasound (2DUS) and 3D smart planes images were respectively used to obtain the basic planes of the fetal brain, with five parameters measured. The images, by either two-dimensional (2D) manual or 3D automatic operation, were reviewed by two experienced sonographers. The agreements between two measurements were analyzed. RESULTS:A total of 226 cases were included. The rates of successful detection by automatic display were as high as 80%. There was substantial agreement between the measurements of the biparietal diameter, head circumference and transcerebellar diameter, but poor agreement between the measurements of cisterna magna and lateral ventricle width. CONCLUSIONS:Smart Planes might be valuable for the rapid evaluation of fetal brain, because it simplifies the evaluation process. However, the technology requires improvement. In addition, this technology cannot replace the conventional manual US scans; it can only be used as an additional approach.