Contact position analysis of deep brain stimulation electrodes on post-operative CT images

Purpose  Groups performing deep brain stimulation advocate post-operative imaging [magnetic resonance imaging (MRI) or computer tomography (CT)] to analyse the position of each electrode contact. The artefact of the Activa 3389 electrode had been described for MRI but not for CT. We undertook an electrode artefact analysis for CT imaging to obtain information on the artefact dimensions and related electrode contact positions. Methods  The electrode was fixed on a phantom in a set position and six acquisitions were run (in-vitro study). The artefacts were compared with the real electrode position. Ten post-operative acquisitions were analysed (in-vivo analysis). We measured: H (height of the lateral black artefact), D (distance between the beginning of the white and the lateral black artefacts) and W (maximal artefact width), representing respectively the lengths of the four contacts and the electrode tip and width of the contact zone. A Student t-test compared the results: in vivo vs in vitro and coronal vs sagittal reconstructions along the electrode. Results  The limits of the lateral black artefact around the electrode contacts corresponded to the final electrode position. There was no significant difference for D (in vivo, 1.1 ± 0.1 mm; in vitro, 1.2 ± 0.2 mm; p = 0.213), while W and H differed slightly (in vivo, W = 3.3 ± 0.2 mm, H = 7.7 ± 0.2 mm; in vitro, W = 3.1 ± 0.1 mm, H = 7.5 ± 0.2 mm). Results obtained with sagittal and coronal reconstructions were similar (p > 0.6). Conclusions  Precise three-dimensional (3D) localisation of the four-contact zone of the electrode can be obtained by CT identification of the limits of the lateral black artefact. The relative position of the four contacts is deduced from the size of the contacts and the inter-contact distance. Sagittal and coronal reconstructions along the electrode direction should be considered for the identification of the four electrode contacts. CT offers a useful alternative to post-operative MRI.     

Testing criteria for spinal implants: recommendations for the standardization of in vitro stability testing of spinal implants

New implants and new surgical approaches should be tested in vitro for primary stability in standardized laboratory tests in order to decide the most appropriate approach before being accepted for clinical use. Due to the complex and still unknown loading of the spine in vivo a variety of different test loading conditions have been used, making comparison of the results from different groups almost impossible. This recommendation was developed in a series of workshops with research scientists, orthopedic and trauma surgeons, and research and development executives from spinal implant companies. The purpose was to agree on in vitro testing conditions that would allow results from various research groups to be compared. This paper describes the recommended loading methods, specimen conditions, and analysis parameters resulting from these workshops. Received: 23 June 1997 Revised: 12 November 1997 Accepted: 23 December 1997     

Simultaneous multi-section perfusion CT and CT angiography for the assessment of acute ischemic stroke

Summary Background. Introduction of helical computed tomography (CT) scanning has enabled rapid imaging of the vascular status by means of CT angiography and perfusion CT. By virtue of recent multi-detector technology, helical CT has the ability to perform both CT angiography and multi-section perfusion CT simultaneously. This study investigated the clinical feasibility of simultaneous assessment of perfusion CT and CT angiography in patients with acute ischemic stroke.Method. Perfusion CT and CT angiography were performed simultaneously in a series of consecutive 31 acute ischemic stroke patients. The time required for the entire processing was about 15 minutes. Contrast agent was used in a total dose of 100ml (35ml for perfusion CT and 65ml for CT angiography).Findings. Simultaneous perfusion CT scans and CT angiographies were of diagnostic quality for 29 patients (94%). In large territorial infarct patients, perfusion CT could predict all perfusion deficits of the final lesions (10 out of 10 lesions) and CT angiography could detect 9 of 10 occlusions of major cerebral arteries (90%). In patients with small lacunar or subcortical infarcts, perfusion CT could predict 9 out of 19 lesions (47.4%), and false-negative were encountered in small lesions (three patients) or in inadequate coverage of data acquisition (seven patients). Acute stage thrombolytic intervention could be carried out based on the findings, and the success of thrombolytic therapy could be demonstrated by follow-up study.Conclusions. Simultaneous perfusion CT and CT angiography is the very useful tool for the rapid and adequate diagnosis of almost all of the large territorial infarcts and some of non-territorial lacunar infarcts. It is an easy-to-perform and safe imaging technique to assess acute ischemic stroke.     

CR、CT、MRI在脊柱结核诊断中的临床价值

[目的]评价计算机X线摄影(CR)、计算机断层成像(CT)、磁共振成像(MRI)在脊柱结核诊断中的临床价值。[方法]回顾分析经病理证实的41例脊柱结核的影像学资料。41例做了CR,22例做了CT,31例均做了MRI。[结果]41例中38例CR片清晰显示骨质改变及椎间隙狭窄或消失,30例CR片可看到软组织阴影。22例CT均清晰显示了钙化,22例CT检查附件均未见明显异常,21例CT清晰显示椎体骨质改变,20例CT显示了软组织阴影。31例MRI均显示软组织均受累,附件均未见受累,其中29例椎间隙狭窄或消失。病变T1WI均以低信号为主,T2WI均以高信号为主。[结论]CR片仍为脊柱结核的基本检查方法,CT较好显示了结核的破坏范围及细微钙化,MRI对显示结核的侵犯范围、软组织异常及椎间盘异常有明显优势。三者相结合有助于脊柱结核的诊断。     

Necessity of Thin Section CT in the Detection of Pulmonary Metastases: Comparison between 5 mm and 1 mm Sections of CT

Background: The aim of this study was to evaluate the difference in the ability of 1-mm and 5-mm section Computed Tomography(CT) to detect pulmonary metastases in patients with pulmonary metastases.Methods: We retrospectively analyzed the CT findings of 106 patients with pulmonary metastases due to malignancies treated at Toho University Omori Medical Center between 2013 and 2020.Results: Cases with only one nodule evaluated by 5-mm section CT had significantly lower discordance with 1-mm section CT than cases with two or more nodules detected by a 5 mm section (p = 0.0161). After reference to a 1 mm section, cases with only one nodule reevaluated by 5-mm section CT had significantly lower discordance than cases with two or more nodules reevaluated using 5-mm section CT. In cases with only one nodule, reevaluation using a 5 mm section was consistent with evaluation using a 1 mm section. However, this was not observed in cases with two or more nodules, with a significant difference between one nodule and two or more nodules.Conclusions: If there are two or more nodules observed in 5-mm section CT it may be necessary to reevaluate using 1-mm section CT to determine the exact number of pulmonary metastases.     

Comparison of pulmonary nodule detection rates between preoperative CT imaging and intraoperative lung palpation

Background

Recent advances in computed tomographic (CT) imaging have improved the detection rate of pulmonary metastasis. The aim of this study was to test the hypothesis that the pulmonary nodule detection rate for preoperative CT imaging and intraoperative palpation are now equivalent.

Methods

A retrospective review of 108 pulmonary metastasectomies in 84 patients was performed. The number of nodules detected on preoperative CT imaging by radiologist report was compared with the number of malignant nodules identified on pathology. Secondary outcome measures were operative approach and primary malignancy.

Results

Sarcoma metastases were the most common indication for resection (n = 54 [50%]). Thirty-three percent of metastasectomies were performed using a thoracoscopic approach. When thoracotomy was used, significantly more nodules were palpated and resected than were identified on preoperative CT imaging (3.24 vs 2.12, P < .001). Significantly more of these nodules were confirmed malignant on final pathology (2.40 vs 1.60, P = .01). This difference was not seen for thoracoscopic resections.

Conclusions

Although the sensitivity of CT imaging has improved, a significant number of malignant pulmonary nodules are detected intraoperatively that are not identified on preoperative imaging. Patients undergoing pulmonary metastasectomy require careful intraoperative palpation of lung parenchyma, and therefore open thoracotomy remains the standard of care.     

单张X线片法与CT法测量股骨颈前倾角的比较

目的 比较单张X线片一次成像测量股骨颈前倾角法与CT法的差异。方法 将31例受检者62髋，利用普通透视摄X片线机，使受检者双下肢固定于屈膝屈髋90。外展60。位，双髋对称，双侧股骨干中轴与骶正中嵴垂直后摄片。测量前倾角，并与CT法测量结果行统计学处理?结果 单张X线片法与CT法测量结果无明显差异，并高度相关。结论 单张X线片法测量股骨颈前倾角与CT法准确度相同。     

100例国人腰椎弓根的CT测量及其临床意义

对１００例国人腰椎弓根进行了ＣＴ形态学测量。结果表明腰椎弓根厚度从Ｌ１～Ｌ５呈递增趋势，Ｌ１～Ｌ５椎弓很平均厚度分别是５．３、 ６．７、９．５、１１．５和１４．７ｍｍ。椎弓根轴线与椎体棘突中央矢状面夹角（倾斜角），从Ｌ１～Ｌ５亦呈递增趋势，Ｌ１～Ｌ５各椎弓根平均倾斜角分别为１５．９７、１５．９１、１９．１９、２２．７８和２８．４７度。本文亦对椎弓根厚度与椎弓根螺钉的直径及进钉倾斜角进行了探讨，并提出在Ｌ４～Ｌ５节段应使用直径７．０ｍｍ的椎弓根螺钉。     

Role of CT and MRI in the design and development of orthopaedic model using additive manufacturing

Objective

To study the role of Computed tomography (CT) and Magnetic resonance imaging (MRI) for design and development of orthopaedic model using additive manufacturing (AM) technologies.

三江地区成人颧骨复合体三维X线头影测量与三维CT测量的比较

目的 探讨颧骨复合体三维X线头影测量与三维CT测量的比较研究.方法 从佳木斯大学在校学生中挑选120名汉族女大学生（出生并生长于三江地区）,年龄19～23岁（平均21.4岁）.采用三维X线头影测量技术和三维CT测量技术,对其面部和颅骨组织做定量测量研究,测量标记点参照祁佐良颧骨颧弓大小的测量方法,测量上面宽、中面宽、下面宽、颧突宽、颧突距和颧突角,并计算骨性面型宽度比值,对以上两种测量结果进行统计学分析.结果 三维CT测量面型宽度比值分别为0.83和0.79,骨性面型宽度比值分别为0.81和0.77;三维X线头影测量面型宽度比值分别为0.84和0.80,骨性面型宽度比值分别为0.82和0.77.两种方法的测量结果差异无统计学意义（P＞0.05）.结论 三维CT测量与三维X线头影测量,均可以应用于颧骨复合体肥大的诊断.     

脊柱原发性大B细胞淋巴瘤CT及MRI表现

目的:探讨脊柱原发性大B细胞淋巴瘤的CT及MRI表现。方法:回顾性分析2011年3月至2015年8月经病理证实的23例脊柱原发性大B细胞淋巴瘤患者的临床表现及CT、MRI资料,男14例,女9例;年龄28~70岁,平均53.4岁。临床症状以脊柱区疼痛为主,少数伴周围神经症状。病程2周~3个月,平均9周。CT平扫9例,CT平扫及增强8例;21例MRI平扫及增强扫描;15例同时行CT及MRI检查;对病灶的部位、骨质改变、形态、密度/信号特点及强化特征进行观察,并与病理进行对照。结果:病变部位及大小:颈椎1例,胸椎16例,腰椎2例,骶椎4例。肿块常较大,最大的横断面73 mm×125 mm。病变类型:23例中15例表现为骨质破坏型,7例为软组织肿块型,无骨髓浸润型。CT及MRI表现:CT示11例伴"云雾"状改变,6例伴压缩性骨折,并伴"浮冰"样改变,伴"袖套"样改变9例;11例伴椎管狭窄;增强扫描明显强化。MRI示T1WI均为稍低信号,T2WI均为稍高信号,信号不均,增强后强化明显,椎管狭窄16例,伴"袖套"样改变13例;椎间隙均无明显狭窄。CT及MRI表现对照:CT对骨质破坏细节的显示明显优于MRI,但其对病灶范围及其周围结构是否受累的显示不及MRI,MRI显示病灶的范围往往大于CT。病理:23例均为脊柱原发性大B细胞淋巴瘤。结论:脊柱原发性大B细胞淋巴瘤发病年龄、部位及影像学表现有一定特征性。CT和MRI表现中"云雾"状、"浮冰"状骨质破坏及椎管内"袖套"样浸润对脊柱原发性大B细胞淋巴瘤的诊断有一定价值。     

多层螺旋CT对胃癌术前临床分期的评估价值

目的　探讨多层螺旋CT (MSCT )下CT仿真胃镜 (CTVG)、三维 (3D)及轴位显像在胃癌术前评估中的应用价值。方法　对 52例经胃镜活检证实的胃癌患者行MSCT扫描后分别再行CTVG以及基于表面遮盖显像 (SSD)及透明显像 (raysum)的 3D显像和轴位显像 ,并与胃镜及手术病理结果对比。结果　CTVG ,3D显像及轴位显像对胃癌原发灶的检出率分别为 98.1 % ,96 .2 %和 96 .2 %。CTVG结合 3D显像 ,胃镜和轴位显像对进展期胃癌大体分型的判断准确率分别为 92 .5 % ,82 .5 %和 75 .0 % ,CTVG结合 3D显像显著高于轴位显像 (P <0 .0 5)。而MSCT轴位显像对胃癌术前T ,N ,M和TNM临床分期的准确率分别为 82 .7% ,79.5 % ,96 .2 %和 79.2 %。结论　MSCT下CTVG ,3D显像和轴位显像对胃癌术前分期有较大的临床应用价值     

Estimation of spinal bone density using conventional MRI: Comparison between MRI and DXA in 32 subjects

We evaluated the usefulness of MRI T1 and T2 relaxation times in assessing bone mineral status. T1 and T2 relaxation times of L3 were measured in 16 pairs of identical twins (24 men, 8 women), aged 25-69 years. Bone mineral density (BMD), bone mineral content (BMC) and apparent volumetric bone mineral density (BMDvol) of L3 were measured from the same subjects using dual x-ray absorptiometry (DXA).

T2 relaxation time correlated inversely with BMD and BMC (r-0.40 and r-0.47, respectively), whereas a significant positive correlation between T1 relaxation time and BMDvol was found (r 0.36). the measurement of T1 may give some information on bone mineral status in clinical MRI measurements when DXA is not available. It is possible that T1 and T2 reflect not only bone density, but also other factors related to bone structure.     

CT angiography of anterior spinal artery in cervical spondylotic myelopathy

Purpose

To identify anterior spinal artery (ASA) infarct or occlusion by CT angiography (CTA) in patients with cervical spondylotic myelopathy (CSM).

Methods

Fourteen patients with CSM were performed CTA of ASA after admission. T2-weighted hyperintensity of MR image was compared with image of CTA of ASA.

Results

All patients presented spinal canal sagittal diameter compression from 10 to 80 % and different T2-weighted hyperintensity of MR images. No ASA infarct or occlusion was found in CSM patients.

Conclusion

ASA infarct or occlusion is not commonly seen in CSM patients with spinal canal sagittal diameter compression less than 80 %. Pathological changes about T2-weighted hyperintensity of MR image in CSM have no close correlation with ASA infarct.     

CT三维重建在治疗下颌角肥大中的临床应用

目的探讨CT三维重建技术在治疗下颌角肥大中的临床指导意义。方法 2009年3月-2011年1月在CT三维重建技术指导下行下颌骨截骨术治疗下颌角肥大18例。患者均为女性;年龄20～36岁,平均25岁。单纯下颌角肥大14例;伴咬肌肥大3例,双侧不对称1例。下垂型6例,外翻型9例,内翻型3例。根据下颌角肥大分型选择合适的手术方法。术前在三维重建工作站上设计并模拟手术过程,标记截骨线及测量截骨量。结果术中无下颌骨骨折发生。术后出现面神经暂时性麻痹1例,3个月后恢复正常。患者均获随访,随访时间6～12个月,平均7.6个月。术后6个月获满意15例,基本满意2例,不满意1例(双侧不对称)。结论根据CT三维重建技术得到头颅三维模型行术前设计可以提高手术准确性,以达到设计的预期效果。     

130例脊柱疾病核素骨显像与MRI、CT、X线诊断的比较研究

目的 比较核素全身骨平面显像和MRI、CT及X线在脊柱转移瘤及其他脊柱疾病诊断中的价值。方法 130例经手术病理诊断的脊柱疾病患者行^99mTc-MDP全身骨平面显像．显示局部异常浓聚、局部异常稀疏和局部加其他部位异常浓聚或稀疏为阳性结果。所有患者均行MRI、CT、X线片三种影像检查的一种以上．其中104例行MRI、61例行CT、107例行X线片检查。结果 骨显像诊断脊柱疾病的灵敏度为：转移瘤91．7％，原发恶性肿瘤73．3％，良性肿瘤54．2％．瘤样病损81．8%，炎性病变100％．压缩性骨折100％。61．1％的转移瘤患者伴有其他部位骨骼的异常浓聚或稀疏灶(58．3％可明确诊断为骨转移瘤)。非转移瘤的其他脊柱痰病．20．2％伴有异位异常浓聚或稀疏灶。MRI、CT和X线的灵敏度分别为：转移瘤96．8％、100％和79.3％；原发恶性肿瘤95．7％、93．3％和78．3％；良性肿瘤95．0%、92．3％和54．5％；瘤样病损100％、100%和80．0％；炎性病变100％、100％和69．2％；压缩性骨折均为100％。结论 核素骨显像是诊断骨转移瘤的最佳方法。对其他脊柱疾病，几种影像技术各有其优势。而核素骨显像对判断病灶是单发抑或多发及是否伴发其他骨骼病变有较大价值。     

Multidetector row helical CT of the pancreas: value of three-dimensional images,two-dimensional reformations,and contrast-enhanced multiphasic imaging

Multidetector row helical computed tomography (MD-CT) scanning is performed for the evaluation of pancreatic tumors. Three-phase contrast study is performed using 2.5-mm collimation, and the images are reconstructed at 1.25-mm intervals. CT angiography and pancreatic duct images using two- or three-dimensional techniques are reconstructed from the volumetric data. MD-CT can perform multiphasic scanning rapidly with an optimal temporal window. CT angiography obtained with MD-CT can delineate peripancreatic vasculature with high spatial resolution and sufficient vascular enhancement. Pancreatic duct images can provide important information in assessing pancreatic disease. MD-CT has the potential to improve detection and preoperative assessment of pancreatic tumors. Received: February 19, 2002 / Accepted: March 10, 2002 Offprint requests to: K. Takeshita     

Cadaveric study validating in vitro monitoring techniques to measure the failure mechanism of glenoid implants against clinical CT

Definite glenoid implant loosening is identifiable on radiographs, however, identifying early loosening still eludes clinicians. Methods to monitor glenoid loosening in vitro have not been validated to clinical imaging. This study investigates the correlation between in vitro measures and CT images. Ten cadaveric scapulae were implanted with a pegged glenoid implant and fatigue tested to failure. Each scapulae were cyclically loaded superiorly and CT scanned every 20,000 cycles until failure to monitor progressive radiolucent lines. Superior and inferior rim displacements were also measured. A finite element (FE) model of one scapula was used to analyze the interfacial stresses at the implant/cement and cement/bone interfaces. All ten implants failed inferiorly at the implant‐cement interface, two also failed at the cement‐bone interface inferiorly, and three showed superior failure. Failure occurred at of 80,966 ± 53,729 (mean ± SD) cycles. CT scans confirmed failure of the fixation, and in most cases, was observed either before or with visual failure. Significant correlations were found between inferior rim displacement, vertical head displacement and failure of the glenoid implant. The FE model showed peak tensile stresses inferiorly and high compressive stresses superiorly, corroborating experimental findings. In vitro monitoring methods correlated to failure progression in clinical CT images possibly indicating its capacity to detect loosening earlier for earlier clinical intervention if needed. Its use in detecting failure non‐destructively for implant development and testing is also valuable. The study highlights failure at the implant‐cement interface and early signs of failure are identifiable in CT images. © 2018 The Authors. Journal of Orthopaedic Research^® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 36:2524–2532, 2018.     

Comparison of whole-body diffusion MRI and conventional radiological assessment in the staging of myeloma

PurposeIn multiple myeloma, skeletal radiographs are still regarded as the reference imaging examination because they help to establish the stage of the disease according to the Durie-Salmon Staging System. Whole-body MRI using T1 and STIR sequences increases the detection of myeloma lesions. MRI-measured diffusion has demonstrated high sensitivity in terms of detection in oncology. The main objective of this study is to compare conventional radiographic staging with an MRI whole-body diffusion technique (called DWIBS) in detecting bone lesion monoclonal plasma cell pathologies (multiple myeloma, plasma cell leukaemia, plasmacytoma and MGUS).Materials and methodsTwenty-seven patients were included (multiple myeloma: 24; plasma cell leukaemia, MGUS and plasmacytoma: 1 each). All of them had a whole-body MRI diffusion examination (using a DWIBS sequence). Diffusion MRI and conventional radiographs were compared according to the Durie-Salmon Staging System. In case of doubtful lesions, 12 months of monitoring was used as the reference method for the definitive diagnosis.ResultsThe overall concordance rate between the two techniques was 63%. The DWIBS sequence detected a higher number of lesions leading to a higher Durie-Salmon stage in 37% of the patients: one stage I to II, seven stage I to III, and two stage II to III. In 18.5% of the patients, the MRI was positive while the radiographs were normal and these discrepancies were most often located in sites poorly explored by X-ray (spine, pelvis and ribs). In one patient (4%), the MRI provided a stage lower than that of the X-rays (stage II vs. III). In this case, the X-rays were positive at the humerus and femur, unlike the DWIBS sequence. Our per site analysis confirmed the clear superiority of the DWIBS sequence when compared with X-rays in the exploration of the cervical spine (56 vs. 0%, P < 0.001), dorsal spine (81vs. 31%,P < 0.0002), lumbar spine (70 vs. 35%, P < 0.0124), pelvis (81 vs. 33%, P < 0.0005) and ribs (74 vs. 36%, P < 0.0009).ConclusionThe DWIBS MRI leads to an increase in the final Durie-Salmon stage. Although its place in the preoperative treatment of multiple myeloma still has to be assessed, this study suggests its potential interest.     

Standard dose versus low-dose abdominal and pelvic CT: Comparison between filtered back projection versus adaptive iterative dose reduction 3D

PurposeTo compare the dose and image quality of a standard dose abdominal and pelvic CT with Filtered Back Projection (FBP) to low-dose CT with Adaptive Iterative Dose Reduction 3D (AIDR 3D).Materials and methodsWe retrospectively examined the images of 21 patients in the portal phase of an abdominal and pelvic CT scan before and after implementation of AIDR 3D iterative reconstruction. The acquisition length, dose and evaluations of the image quality were compared between standard dose FBP images and low-dose images reconstructed with AIDR 3D and FBP using the Wilcoxon test.ResultsThe mean acquisition length was similar for both CT scans. There was a significant dose reduction of 49.5% with low-dose CT compared to standard dose CT (mean DLP of 451 mGy.cm versus 892 mGy.cm, P < 0.001). There were no differences in image quality scores between standard dose FBP and low-dose AIDR 3D images (4.6 ± 0.6 versus 4.4 ± 0.6 respectively, P = 0.147).ConclusionAIDR 3D iterative reconstruction enables a significant reduction in dose of 49.5% to be achieved with abdominal CT scan compared to FBP, whilst maintaining equivalent image quality.