• Journal of Korean Neurosurgical Society
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• 제60권4호
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• pp.448-455
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• 2017

Objective : To investigate the magnetic resonance imaging (MRI) findings and the patterns of postoperative spinal infection according to the passage of time. Methods : Institutional review board approval was obtained, and informed consent was not obtained for the retrospective review of patients' medical records. A total of 43 patients (27 men and 16 women; mean age, 64) diagnosed with postoperative spinal infection were included in this study. We retrospectively reviewed the MRI findings and the medical records and categorized the infection sites based on MRI, i.e., anterior, posterior, and both parts. The duration of the clinical onset from surgery was divided, i.e., acute (${\leq}2weeks$), subacute (2-4 weeks), and late (>4 weeks). Results : Postoperative spinal infection was involved in the posterior part in 31 (72%), anterior part in two (4.7%), and both parts in 10 patients (23.3%). Abscess or phlegmon in the back muscles and laminectomy site were the most common MRI findings. The number of patients with acute, subacute, and late clinical onset were 35, two, and six, respectively (mean, 33.4 days; range, 1-730 days). The mean duration of the clinical onset was 12 days in the posterior part, 15.2 days in both parts, and 456.5 days in the anterior part. Conclusion : Postoperative spinal infection usually occurred within four weeks in the posterior part and over time the infection was considered to spread into the anterior part. For the evaluation of postoperative spinal infection, the posterior surgical field was more important than the vertebral body or the disc space on MRI.

• Journal of Korean Neurosurgical Society
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• 제60권5호
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• pp.577-583
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• 2017

Objective : Laminoplasty is an effective surgical method for treating cervical degenerative disease. However, postoperative complications such as kyphosis, restriction of neck motion, and instability are often reported. Despite sufficient preoperative lordosis, this procedure often aggravates the lordotic curve of the cervical spine and straightens cervical alignment. Hence, it is important to examine preoperative risk factors associated with postoperative kyphotic alignment changes. Our study aimed to investigate preoperative radiologic parameters associated with kyphotic deformity post laminoplasty. Methods : We retrospectively reviewed the medical records of 49 patients who underwent open door laminoplasty for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) at Pusan National University Yangsan Hospital between January 2011 and December 2015. Inclusion criteria were as follows : 1) preoperative diagnosis of OPLL or CSM, 2) no previous history of cervical spinal surgery, cervical trauma, tumor, or infection, 3) minimum of one-year follow-up post laminoplasty with proper radiologic examinations performed in outpatient clinics, and 4) cases showing C7 and T1 vertebral body in the preoperative cervical sagittal plane. The radiologic parameters examined included C2-C7 Cobb angles, T1 slope, C2-C7 sagittal vertical axis (SVA), range of motion (ROM) from C2-C7, segmental instability, and T2 signal change observed on magnetic resonance imaging (MRI). Clinical factors examined included preoperative modified Japanese Orthopedic Association scores, disease classification, duration of symptoms, and the range of operation levels. Results : Mean preoperative sagittal alignment was $13.01^{\circ}$ lordotic; $6.94^{\circ}$ lordotic postoperatively. Percentage of postoperative kyphosis was 80%. Patients were subdivided into two groups according to postoperative Cobb angle change; a control group (n=22) and kyphotic group (n=27). The kyphotic group consisted of patients with more than $5^{\circ}$ kyphotic angle change postoperatively. There were no differences in age, sex, C2-C7 Cobb angle, T1 slope, C2-C7 SVA, ROM from C2-C7, segmental instability, or T2 signal change. Multiple regression analysis revealed T1 slope had a strong relationship with postoperative cervical kyphosis. Likewise, correlation analysis revealed there was a statistical significance between T1 slope and postoperative Cobb angle change (p=0.035), and that there was a statistically significant relationship between T1 slope and C2-C7 SVA (p=0.001). Patients with higher preoperative T1 slope demonstrated loss of lordotic curvature postoperatively. Conclusion : Laminoplasty has a high probability of aggravating sagittal balance of the cervical spine. T1 slope is a good predictor of postoperative kyphotic changes of the cervical spine. Similarly, T1 slope is strongly correlated with C2-C7 SVA.

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.376-381
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• 2019

Objective : To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine. Methods : Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated. Results : The average transverse angles were $50.60^{\circ}{\pm}6.22^{\circ}$ at C3, $51.42^{\circ}{\pm}7.44^{\circ}$ at C4, $47.79^{\circ}{\pm}7.61^{\circ}$ at C5, and $41.24^{\circ}{\pm}7.76^{\circ}$ at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were $9.72^{\circ}{\pm}6.73^{\circ}$ downward at C3, $5.09^{\circ}{\pm}6.39^{\circ}$ downward at C4, $0.08^{\circ}{\pm}6.06^{\circ}$ downward at C5, and $1.67^{\circ}{\pm}6.06^{\circ}$ upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6. Conclusion : The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.

• Journal of Korean Neurosurgical Society
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• 제64권4호
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• pp.575-584
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• 2021

Objective : Cervical expansive laminoplasty is an effective surgical method to address multilevel cervical spinal stenosis. During surgery, the spinous processes of C2 and C7 are usually preserved to keep the insertion points of the cervical musculature and nuchal ligament intact. In this regard, dome-like laminectomy (undercutting of C7 lamina) instead of laminoplasty is performed on C7 in selected cases. However, resection of the lamina can weaken the C7 lamina, and stress fractures may occur, but this complication has not been characterized in the literature. The objective of the present study was to investigate the incidence and risk factors for C7 laminar fracture after C7 dome-like laminectomy and its impact on clinical and radiological outcomes. Methods : Patients who underwent cervical open-door laminoplasty combined with C7 dome-like laminectomy (n=123) were classified according to the presence of C7 laminar fracture. Clinical parameters (neck/arm pain score and neck disability index) and radiologic parameters (C2-7 angle, C2-7 sagittal vertical axis, and C7-T1 angle) were compared between the groups preoperatively and at postoperatively at 3, 6, 12, and 24 months. Risk factors for complications were evaluated, and a formula estimating C7 fracture risk was suggested. Results : C7 lamina fracture occurred in 32/123 (26%) patients and occurred at the bilateral isthmus in 29 patients and at the spinolaminar junction in three patients. All fractures appeared on X-ray within 3 months postoperatively, but patients did not present any neurological deterioration. The fracture spontaneously healed in 27/32 (84%) patients at 1 year and in 29/32 (91%) at 2 years. During follow-up, clinical outcomes were not significantly different between the groups. However, patients with C7 fractures showed a more lordotic C2-7 angle and kyphotic C7-T1 angle than patients without C7 fractures. C7 fracture was significantly associated with the extent of bone removal. By incorporating significant factors, the probability of C7 laminar fracture could be assessed with the formula 'Risk score = 1.08 × depth (%) + 1.03 × length (%, of the posterior height of C7 vertebral body)', and a cut-off value of 167.9% demonstrated a sensitivity of 90.3% and a specificity of 65.1% (area under the curve, 0.81). Conclusion : C7 laminar fracture can occur after C7 dome-like laminectomy when a substantial amount of lamina is resected. Although C7 fractures may not cause deleterious clinical outcomes, they can lead to an unharmonized cervical curvature. The chance of C7 fracture should be discussed in the shared decision-making process.

• 한방재활의학과학회지
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• 제32권1호
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• pp.51-62
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• 2022

Objectives Objective of this study is to investigate the role of paraspinal muscles by examining the correlation between slip percentage (SP) of spondylolisthesis and fatty infiltration of lumbar paraspinal muscle. Methods Retrospective analysis was performed on 45 patients diagnosed with spondylolisthesis based on medical records. Using T2-weighted axial magnetic resonance imaging, cross-sectional areas (CSAs) of psoas major (PM), multifidus (MU) and erector spinae (ES) were calculated and divided by CSA of lower level vertebral body (VB). SP was measured using sagittal T2-weighted images. Correlation of SP with muscle relative cross-sectional area (RCSA) and muscle fatty infiltration by Goutallier classification was respectively analyzed using Spearman correlation. Statistic assessment conducted by Wilcoxon signed rank test and paired t-test using program GraphPad prism 5 (GraphPad Software, Inc., San Diego, CA, USA). Results Spondylolisthesis forward slip percentage by Taillard's method was negatively associated with both side MU RCSAs. No significant correlation was found between PM RCSA, ES RCSA and SP. Forward slippage was significantly correlated with fatty infiltration of lumbar paraspinal muscle measured by Goutallier classification. Conclusions This study is to understand the role of paraspinal muscle affecting spinal instability by investigating correlation between statistical deviation of lumbar muscle characters (RCSA, fatty infiltration of lumbar muscle) and SP. We found that spondylolisthesis SP is positively related to fatty infiltration of lumbar paraspinal muscle. and is negatively associated with both side MU RCSAs.

• 대한영상의학회지
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• 제82권6호
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• pp.1413-1440
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• 2021

MRI에서 추간판의 이상 신호와 위, 아래 척추체 종판의 파괴, 종판 주변의 골수부종 등은 감염성 척추염의 전형적인 소견으로 여겨지나 퇴행성 척추질환, acute Schmorl's node, 척추관절병증, synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis, 척추신경관절병증, calcium pyrophosphate dehydrate 결절침착질환 등 다양한 비감염성 척추질환에서도 나타날 수 있다. MRI에서 이러한 비감염성 척추질환과 감별되는 감염성 척추염의 영상 소견은 추간판의 고신호와 농양, 척추 연부조직의의 농양, 그리고 T1 강조영상에서 저신호로 보이는 종판의 경계가 불명확해지는 점 등이다. 그러나 이러한 감별점이 항상 적용되는 것은 아니며 감염성, 비감염성 질환의 영상 소견에 유사점이 많기 때문에 정확한 진단을 위해서는 감염성 척추염뿐만 아니라 감염과 감별해야 하는 다양한 질환의 병태생리와 연관된 영상학적 특징을 아는 것이 중요하다.

• Korean Journal of Radiology
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• 제22권11호
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• pp.1850-1857
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• 2021

Objective: The purpose of this study was to assess whether a deep learning (DL) algorithm could enable simultaneous noise reduction and edge sharpening in low-dose lumbar spine CT. Materials and Methods: This retrospective study included 52 patients (26 male and 26 female; median age, 60.5 years) who had undergone CT-guided lumbar bone biopsy between October 2015 and April 2020. Initial 100-mAs survey images and 50-mAs intraprocedural images were reconstructed by filtered back projection. Denoising was performed using a vendor-agnostic DL model (ClariCT.AI^TM, ClariPI) for the 50-mAS images, and the 50-mAs, denoised 50-mAs, and 100-mAs CT images were compared. Noise, signal-to-noise ratio (SNR), and edge rise distance (ERD) for image sharpness were measured. The data were summarized as the mean ± standard deviation for these parameters. Two musculoskeletal radiologists assessed the visibility of the normal anatomical structures. Results: Noise was lower in the denoised 50-mAs images (36.38 ± 7.03 Hounsfield unit [HU]) than the 50-mAs (93.33 ± 25.36 HU) and 100-mAs (63.33 ± 16.09 HU) images (p < 0.001). The SNRs for the images in descending order were as follows: denoised 50-mAs (1.46 ± 0.54), 100-mAs (0.99 ± 0.34), and 50-mAs (0.58 ± 0.18) images (p < 0.001). The denoised 50-mAs images had better edge sharpness than the 100-mAs images at the vertebral body (ERD; 0.94 ± 0.2 mm vs. 1.05 ± 0.24 mm, p = 0.036) and the psoas (ERD; 0.42 ± 0.09 mm vs. 0.50 ± 0.12 mm, p = 0.002). The denoised 50-mAs images significantly improved the visualization of the normal anatomical structures (p < 0.001). Conclusion: DL-based reconstruction may enable simultaneous noise reduction and improvement in image quality with the preservation of edge sharpness on low-dose lumbar spine CT. Investigations on further radiation dose reduction and the clinical applicability of this technique are warranted.

• 대한방사선치료학회지
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• 제30권1_2호
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• pp.41-47
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• 2018

목 적 : 사이버나이프(Accuray Inc., Sunnyvale, CA)를 이용한 제1, 2경추의 정위체부방사선치료(Stereotactic Body Radiation Therapy, SBRT)시 사용가능한 Xsight Spine Tracking(XST)과 6-Dimensional Skull Tracking(6DST)의 비교를 통해 6DST의 유용성을 평가하고자 한다. 대상 및 방법 : 2017년 1월부터 9월까지 본원에서 사이버나이프를 이용하여 제1, 2경추에 SBRT를 진행한 환자 9명을 대상으로, 전산화단층촬영장치(Lightspeed VCT 64, General Electric Co. Waukesha, WI, USA)를 이용해서 컴퓨터 단층 영상(Computed tomography) 을 획득한 후 전산화치료계획시스템(Multiplan system Version 4.6, Accuray, US)를 이용해 제 1, 2경추에 대한 XST와 6DST가 가능한 계획을 수립하였다. 1차 영상 유도를 통해 환자 자세를 보정한 후 동일 환자에 대한 XST와 6DST를 순서대로 진행하고 측정된 결과값을 비교 평가하였다. 결 과 : 제1경추를 대상으로 XST을 실시한 후 측정된 6D Couch 의 Y, Z, X 축 값과 Roll, Pitch, Yaw 값 중 최대값은 0.9 mm, 0.9 mm, 0.7 mm과 $1.0^{\circ}$, $1.0^{\circ}$, $1.2^{\circ}$로 측정되었고, 6DST의 경우 0.7 mm, 0.7 mm, 0.9 mm과 $0.5^{\circ}$, $0.9^{\circ}$, $0.8^{\circ}$로 측정되었다. 제2경추의 XST를 실시했을 때 측정된 값 중 최대값은 0.7 mm, 0.7 mm, 0.8 mm과 $0.9^{\circ}$, $1.0^{\circ}$, $1.8^{\circ}$였고, 6DST의 경우 0.9 mm, 0.7 mm, 0.9 mm와 $0.9^{\circ}$, $0.9^{\circ}$, $1.0^{\circ}$로 측정되었다. 결 론 : 이번 연구를 통해서 제 1, 2 경추에 대한 XST와 6DST의 6D Couch 측정값이 모두 본원에서 기준으로 하고 있는 범위 안에서 측정되고 있음을 확인할 수 있었다. 또한 두 방법을 진행하는 과정에서 설정값 변경을 진행해야하는 XST보다 6DST가 영상유도절차를 간소화 시킬 수 있다는 것을 확인할 수 있었다. 따라서 제 1, 2 경추에 대한 SBRT를 진행할 경우 XST와 더불어서 6DST를 사용한다면 정확한 치료와 더불어서 치료 시간을 단축시킬 수 있을 것으로 사료된다.

• 핵의학기술
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• 제18권1호
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• pp.49-61
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• 2014

인구의 고령화와 함께 골다공증성 척추압박골절 환자의 발병률은 매년 증가하는 추세이며 경피적 척추성형(percutaneous vertebroplasty, PVP)은 가장 많이 시행되는 표준화된 치료 방법이다. 시술 전 후의 정확한 진단평가에 있어 SPECT/CT 검사의 유용성이 우수하다는 연구 보고가 있으나 시술에 사용되는 골 시멘트(bone cement) 물질은 CT 영상에서 인공물(artifact)을 생성하여 영상품질에 영향을 미친다. 이에 본 연구에서는 골 시멘트가 SPECT/CT 영상에 미치는 영향을 평가하는 데 목적을 두었다. NEMA-1994 팬텀(phantom)에 배후방사능(3.6 kBq/ml), 열소(29.6 kBq/ml), 냉소(물)를 설정한 후 각 원통(cylinder)에 모형 시멘트를 삽입하여 영상 획득하였다. Astonish (Iterative: 4, Subset: 16)으로 재구성하였고, CT 보정 방법은 비감쇠보정(NAC), 감쇠보정(AC+SC-), 감쇠 및 산란보정(AC+SC+) 3가지 방법을 사용하였다. 각각의 보정방법에 따른 평균계수와 시멘트물질의 유 무에 따른 계수 변화율을 비교하고 대조도 회복 계수(contrast recovery coefficient, CRC)를 구했다. 또한, 압박골절 진단을 받은 환자 107명 중 PVP를 시행한 20명을 선별하여 추체를 골절, 정상, 시멘트로 나누고 연조직(척추기립근)을 포함 4곳의 평균 계수를 측정한 후, 뼈/연조직 간 계수 비(bone/soft tissue ratio, B/S ratio)을 구했다. NAC를 기준으로 AC+SC-, AC+SC+의 평균계수는 증가하였고, AC+SC-의 평균계수가 가장 높았으며, AC+SC+는 AC+SC-에 비해 상대적으로 낮았다. 시멘트 물질의 유 무에 따른 평균계수는 시멘트가 존재할 때 NAC, AC+SC-, AC+SC+에 따라 팬텀의 열소에서 12.4%, 6.5%, 1.5%, 냉소 75.2%, 85.4%, 102.9%, 배후방사능 13.6%, 18.2%, 9.1%, 임상영상의 골절부에서 33.1%, 41.4%, 63.5%, 정상부 53.1%, 61.6%, 67.7%, 연조직 10.0%, 4.7%, 3.6%의 증가율을 보였다. 반면 원통 내부의 시멘트 인접부에서 상대적 계수감소를 확인할 수 있었고, 병소에 대한 팬텀영상과 임상영상간의 계수 증가율은 상반된 양상을 보였다. 대조도 비를 나타내는 CRC와 B/S ratio는 NAC, AC+SC-, AC+SC+순으로 향상되었고, 팬텀의 냉소에서는 큰 변화 없이 일정하였다. 정량적 계수는 AC+SC-가, 대조도 비는 AC+SC+가 가장 높게 분석되었다. PVP 시행 환자의 척추 뼈 SPECT/CT 검사에서 AC+SC- 의 사용은 영상계수를 대폭 향상시켜 특히 병소의 농도가 높은 영상을 얻는 반면에 골 시멘트의 영향과 함께, 연부조직 및 산란영역의 영상잡음 계수까지 증가시키므로 대조도비를 향상시키는 AC+SC+의 적용을 병행한다면 임상진단에 유용할 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제21권4호
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• pp.273-284
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• 1996

착상전기(着床前期}의 태아(胎兒)는 방사선(放射線)을 비롯한 많은 환경요인(環境要因)에 대하여 감수성(感受性)이 높은 개체(個體)임에도 불구하고 특히 이 시기는 임신부(姙娠婦)가 자각(自覺)적으로 임신을 감지할 수 없는 시기이기에 이러한 여러 환경유해요인으로부터 의도적으로 피할 수가 없다. 그러므로 착상전기의 영향을 충분히 검토한 후에 의료행위를 취할 것이며 이에 대한 방어(防禦)대책도 검토할 필요가 있다. 종래 까지 방사선에 대한 태아영향에 관한 많은 연구결과에 의하면 방사선 및 그 외의 유해요인에 대한 착상전기의 영향은 배사망(胚死亡)(유산(流産))만이 일어나며 기형(奇形)은 유발(誘發)하지 않는다고 하여 발생학(發生學)등 여러 교과서에서 기형은 기관형성기(器官形戚期)만이 국한(局限)해서 일어나는 영향이라고 단정되어 왔었다. 그러나 이 연구결과 착상전기에 있어서도 기형이 유발하여 오히려 기관형성기((器官形成期)보다도 감수성이 높다는 것이다. 또한 착상전기에서도 기형유발의 시기특이성을 가지며 여러 종류의 기형이 발생한다는 것이 본 연구로부터 밝혀졌다. 실험동물은 ICR Mouse를 사용했다. ICR Mouse는 일반적으로 태아사망 및 기형실험에 널리 사용되는 것이다. 사육조건은 Conventional 한 조건하에서 사육했으며 Mating 방법(方法)은 Female 마우스의 발정기(Sexual Excitement period)에 있는 mouse 질(膣)을 육안 적으로 관찰하여 $AM 6:00{\sim}AM 9:00$시까지 3시간만 mate시켰다. AM9:00시에 Vaginal Plug를 관찰하여 임신을 확인했다. Plug가 확인 된 마우스는 AM8:00시에 수정(Conception)된 것으로 가정하고 이 시점을 임신 0일 0시로 수정 난의 태아연령을 산정했다. 방사선조사는 $^{135}Cs\;{\gamma}-$선을 사용하였으며 임신 마우스의 전신조사를 실시하고 조사한 시기는 각 2, 48, 72, 96hpc이며 조사한 방사선 선량 군은 $0.1{\sim}2.5Gy$이다. 태아영향 관찰지표는 태아 연령은 mate일 오전 8:00시를 임신 0일 0시로 환산하여 태아연령 18일에 임신마우스를 Cervical vertebral dislocation에 의해 도살했다. 도살 후 해부하여 각 임신 마우스별로 관찰했다. 착상 율을 관찰하기 위하여 황체수를 세었고, 태아사망과 생존태아를 구별했다. 자궁 내 사망의 분류는 태아사망을 1) preimplantation death 2) Embryonic death 3) Fetal death로 분류했다. 착상전사망은 수정후 $0{\sim}4.5$일(1세포기${\sim}$배반포후기 부화까지)까지의 사망으로써 난소의 황체수(배란 수)와 착상태아(생존태아, 착상흔, 태반유잔, 흡수태아, 침연태아의 합계)로부터 구할 수 있다. Embonic death는 수정 후 $4.5{\sim}13$일까지의 사망으로써 Implantation sites, Placental remnants, Resorption of fetus로 관찰된 것이다. Fetal death는 수정후 $14{\sim}18$일까지의 사망으로써 Maceration of fetus로 관찰되는 것이다. 통계학적 분석은 각 Group의 착상 을과 자궁 내 사망 율을 산출할 때에는 각 임신마우스에 따라 발생빈도가 크게 다르기 때문에 통계처리에는 Non parametric 검정인 Kluskal Wallis 검정을 사용하여 분석하였다. 또한 개체 Level 영향인 착상을, 태아사망, 기형의 threshold dose의 산정에 대해서는 SAS-Logistic 검정에 따라 통계 분석을 하여 $5%(Ld_5,\;ED_5)$ 및 $10%{\times}2/3$점을 threshold dose로 판단했다. 태아체 중에 대해서는 parametric검정인 t-test검정에 의하여 분석했다. 그 결과 착상전기에서도 기형이 유발하며 특히 시기에 따라 일어나는 때와 일어나지 않는 때가 있음을 본 연구로부터 밝혀졌다. 또한 착상전기의 영향으로써 유발되는 기형은 여러 종류의 기형이 발생함이 밝혀졌다. 특히 이시기는 착상전 사망 및 배(胚)사망은 방사선 선량에 따라 크게 일어나나 태아사망(Fetal death) 및 태아체중은 유의차(有意差)가 없었다.