Spine Computed Tomography Research Articles

Evolving Radiology Trainee Neuroimaging Workloads: A National Medicare Claims-based Analysis

While radiology training programs aim to prepare trainees for clinical practice, the relationship between trainee, and national radiology workforce demands is unclear. This study assesses changing radiology trainee neuroimaging workloads nationwide for neuroimaging studies. Using aggregate Medicare claims files from 2002 to 2018, we identified all computed tomography (CT) and magnetic resonance (MR) examinations of the brain, head and neck, and spine (hereafter "neuroimaging") in Medicare fee-for-service beneficiaries nationwide. Using separate Medicare files, we calculated population utilization rates, and work relative value unit (wRVU) weights of all diagnostic neuroradiology services. Using claims modifiers, we identified services rendered by radiology trainees. Using separate national trainee enrollment files, we calculated mean annual per trainee wRVUs. Between 2002 and 2018, total Medicare neuroimaging claims increased for both radiologists overall (86.1%) and trainees (162.5%), including increases in both CT (102.9% vs 196.8%), and MR (59.9% vs 106.6%). The national percentage of all radiologist neuroimaging wRVUs rendered by trainees increased 46.1% (3.8% of all wRVUs nationally in 2002 to 5.6% in 2018). National trainee increases were present across all neuroimaging services but greatest for head and neck CT (+86.5%). Mean annual per radiology trainee neuroimaging Medicare wRVUs increased +174.9% (42.1 per trainee in 2002 to 115.70 in 2018). Mean per trainee wRVU increases were greatest for spine CT (+394.2%) but present across all neuroimaging services. As neuroimaging utilization in Medicare beneficiaries has grown, radiology trainee neuroimaging workloads have increased disproportionately.

Combined lumbar spine MRI and CT appropriateness checklist: a quality improvement project in Saskatchewan, Canada

BackgroundAs rates of advanced imaging for lower back pain (LBP) continue to increase, there is a need to ensure the appropriateness of imaging.ObjectiveThe goal of this project was to reduce the number of inappropriate magnetic resonance imaging (MRI) and computed tomography (CT) requests for LBP patients and facilitate appropriate imaging by developing a combined imaging appropriateness checklist for lumbar spine MRI and CT.MethodsIn prior work, we developed and adopted individual evidence-based lumbar spine MRI and CT checklists into the radiology requisition process. In the current project, a combined checklist was developed and trialed in one of the former Saskatchewan health regions (Five Hills) beginning in May 2018. Using statistical process control, control charts compared the monthly number of imaging requests pre-checklist implementation and post-checklist implementation from May 2017 to February 2020. The monthly number of lumbar spine MRI and CT requisitions in the nearby former Saskatchewan Regina Qu’Appelle Health Region, in which the combined checklist was not trialed, was also plotted and compared as a balancing measure.ResultsIn Five Hills, a shift (decrease) was observed in the monthly number of lumbar spine MRI requisitions 7 months following the implementation of the combined checklist. However, the monthly number of lumbar spine CT requisitions did not change significantly. In the Regina Qu’Appelle Health Region, there was a shift (increase) in the monthly number of lumbar spine MRI requisitions, while the monthly number of lumbar spine CT requests decreased after the implementation of the combined checklist.ConclusionsThe combined checklist with evidence-based indications for lumbar spine MRI and CT imaging in LBP patients appeared to reduce the complexity associated with two previous individual checklists and facilitate imaging appropriateness. Accountable benefits may include the reduction of radiation exposure as a result of unnecessary and repeated imaging and reduction in wait times for CT and/or MRI.

Morphometric and volumetric analysis of the cervical spinal cord and vertebral canal using computed tomography images in normal Van cats.

This study was performed on Van cats to determine the volumetric, morphometric and surface area measurement values of their cervical spinal cords (SC) and vertebral canals (CC) and the ratios between their dimensions using computed tomography (CT) images. The study also aims to reveal any biometric differences in these values between the two sexes. Spinal cord and vertebral canal CT images of 16 healthy adult Van cats (8 males and 8 females) were used in the study. First, three measurement points were selected for each vertebra on their cranial, medial and caudal sections along the sagittal axis. Next, the morphometric values were obtained using the transversal images of these measurement points. The surface areas for the SC and CC were calculated using the stereological planimetry method. The Cavalieri's principle was then used to calculate the relevant anatomic structure volumes. The obtained values were then statistically analysed. SC and CC were found to be larger in males in general, while 'SC cranial/CC cranial' and 'SC medial/CC medial' dimensions and volume ratios were found to be larger in female cats on average. Bodyweight and age values were found to have a negative correlation with SC and CC ratio, but the correlation was statistically insignificant. All SC and CC surface area and volume measurements were found to be higher in male cats (p<.05). We believe the results obtained by this study will provide valuable insight into veterinary clinicians in evaluating pathological lesions in the cervical spinal cord and vertebral canal CT scans.

Variation in pediatric cervical spine imaging across trauma centers-A cause for concern?

BACKGROUNDTraumatic pediatric cervical spine injury can be challenging to diagnose, and the clinical algorithms meant to aid physicians differ from adult trauma protocols. Despite the existence of standardized guidelines, imaging decisions may vary according to physician education, subjective assessment, and experience with pediatric trauma patients. Our study investigates the rates of pediatric posttraumatic cervical spine imaging across trauma centers, hypothesizing that more specialized centers will have lower rates of advanced cervical spine imaging.METHODSThe 2015 to 2016 Trauma Quality Improvement Program database was reviewed for patients younger than 18 years- to assess rates of cervical spine imaging on presentation across different trauma centers. Propensity stratification logistic regression was performed controlling for patient- and center-specific variables. p Values less than 0.05 were considered significant.RESULTSOf 110,769 pediatric trauma patients, 35.2% were female, and the average age was 9.6 years. Overall, 3.6% had cervical spine computed tomography (CT) and less than 1% had cervical spine MRI or X-ray. Compared with all others, Level I trauma centers were significantly less likely to use cervical spine CT for the initial evaluation of younger (≤14 years) but not older trauma patients (adjusted odds ratio [AOR], 0.89; 95% confidence interval [CI], 0.80–0.99; AOR, 0.97; 95% CI, 0.87–1.09); Level I centers had higher odds of cervical spine MRI use, but only for patients 14 years or younger (AOR, 1.63; 95% CI, 1.09–2.44). Pediatric-designated trauma centers had significantly lower odds of cervical spine CT (≤14 years: AOR, 0.70; 95% CI, 0.63–0.78; >14 years: AOR, 0.67; 95% CI, 0.67–0.75) and higher odds of cervical spine X-ray (≤14 years: AOR, 4.75; 95% CI, 3.55–6.36; >14 years: AOR, 4.50; 95% CI, 2.72–7.45) for all ages, but higher odds of cervical spine MRI for younger patients only (≤14 years: AOR, 2.10; 95% CI, 1.38–3.21).CONCLUSIONLevel I and pediatric designations were associated with lower rates of cervical spine CT. Pediatric centers were also more likely to use cervical spine X-ray. This variability of imaging use further supports the need to disseminate and educate providers on pediatric-specific cervical spine evaluation guidelines.LEVEL OF EVIDENCEPrognostic and epidemiological, level III.

3D vertebrae labeling in spine CT: an accurate, memory-efficient (Ortho2D) framework

Purpose. Accurate localization and labeling of vertebrae in computed tomography (CT) is an important step toward more quantitative, automated diagnostic analysis and surgical planning. In this paper, we present a framework (called Ortho2D) for vertebral labeling in CT in a manner that is accurate and memory-efficient. Methods. Ortho2D uses two independent faster R-convolutional neural network networks to detect and classify vertebrae in orthogonal (sagittal and coronal) CT slices. The 2D detections are clustered in 3D to localize vertebrae centroids in the volumetric CT and classify the region (cervical, thoracic, lumbar, or sacral) and vertebral level. A post-process sorting method incorporates the confidence in network output to refine classifications and reduce outliers. Ortho2D was evaluated on a publicly available dataset containing 302 normal and pathological spine CT images with and without surgical instrumentation. Labeling accuracy and memory requirements were assessed in comparison to other recently reported methods. The memory efficiency of Ortho2D permitted extension to high-resolution CT to investigate the potential for further boosts to labeling performance. Results. Ortho2D achieved overall vertebrae detection accuracy of 97.1%, region identification accuracy of 94.3%, and individual vertebral level identification accuracy of 91.0%. The framework achieved 95.8% and 83.6% level identification accuracy in images without and with surgical instrumentation, respectively. Ortho2D met or exceeded the performance of previously reported 2D and 3D labeling methods and reduced memory consumption by a factor of ∼50 (at 1 mm voxel size) compared to a 3D U-Net, allowing extension to higher resolution datasets than normally afforded. The accuracy of level identification increased from 80.1% (for standard/low resolution CT) to 95.1% (for high-resolution CT). Conclusions. The Ortho2D method achieved vertebrae labeling performance that is comparable to other recently reported methods with significant reduction in memory consumption, permitting further performance boosts via application to high-resolution CT.

Correlation of Bone Density Values of Quantitative Computed Tomography and Hounsfield Units Measured in Native Computed Tomography in 902 Vertebral Bodies

Due to the increasing age of patients, the evaluation of bone density is crucial, especially in preparation for spinal surgery. The aim of this study was to determine bone density using a computed tomography (CT) and to correlate Hounsfield units (HU) with bone density values of a quantitative computed tomography (QCT). The study is a monocentric, retrospective data analysis. We examined 902 vertebral bodies from a total of 369 patients who received a CT of the thoracolumbar spine in the period from 2015 to 2019 and compared the HU with values of a QCT. A general equation for calculation the QCT values was established. We found a significant correlation between the Hounsfield units and the corresponding QCT-values (r= 0.944, P < 0.001). We also demonstrated that the calculated QCT values are independent of patient sex (P < 0.942). Furthermore, we could not demonstrate differences in the correlation of the 3 measured levels (axial, sagittal, and coronary) to the QCT values. The QCT-values can be calculated on the basis of a native CT of the lumbar spine using the equation: QCT= 17.8+ 0.7× HU. The equation allows calculating bone density values without the need for an additional QCT and without further radiation exposure or costs. With this measuring method it is possible to obtain additional information from a computed tomography.

Real-time ultrasound-computed tomography image fusion for transforaminal lumbar approach: a lumbosacral spine phantoms study.

Ultrasound (US) is increasingly used for transforaminal approaches. We evaluated whether fusing computed tomography (CT) images with dynamic US could be based on bony and surface landmarks in two phantom models. Recordings were performed in a gelatin-based sonographic phantom and in a computerized imaging reference system training phantom. Three anesthesiologists performed 10 US and CT image fusions via three different techniques: (1) using locations of the fifth lumbar vertebra (L5) spinous process and the two posterior superior iliac spines in both images, (2) using the two lateral edges of the laminae rather than posterior superior iliac spines, and (3) using skin landmarks. Techniques were compared using values of precision (High quality of fusion: VP inferior to 10). Three punctures targeting the L4-L5 right foramina were made, and needle positions were checked using X-ray. Sixty fusions were performed in the gelatin phantom and 90 in the training phantom. VPs values of the 150 fusions were inferior to 5. Technique 2 was superior to one [operator 1: VP: 1.12 ± 0.54 vs. 2.38 ± 1.49; operator 2: 0.6 ± 0.39 vs. 3.66 ± 1.22; operator 3: 0.89 ± 0.31 vs. 1.23 ± 0.63 (p < 0.001)] with the gelatin phantom. There were no differences with the second phantom. X-ray examinations confirmed L4-L5 needle positioning. Bony and surface landmarks allowed for accurate fusion of CT and US images of the lumbar spine. These techniques, performed on phantoms, allowed for precise localization and puncturing of lumbar neural foramina.

Implementation of a dual cervical spine and blunt cerebrovascular injury assessment pathway for pediatric trauma patients.

Pediatric cervical spine (CSI) and blunt cerebrovascular injuries (BCVI) are challenging to evaluate as they are rare but carry high morbidity and mortality. CT scans are the traditional imaging modality to evaluate for CSI/BCVI, but involve radiation exposure and potential future increased risk of malignancy. Therefore, we present results from the implementation of a combined CSI/BCVI pediatric trauma clinical pathway to aid clinicians in their decision-making. We conducted a 2-year retrospective cohort study analyzing data pre and post implementation of the combined CSI/BCVI pathway. Data was obtained from a level 1 pediatric trauma center and included blunt trauma patients under the age of 14. We evaluated the use of cervical spine computed tomography (CT), CT angiography, and plain radiographs, as well as missed injuries and provider pathway adherence. We included 358 patients: 209 pre-pathway and 149 post-pathway implementation. Patient mean age was 8.9 years and 61% were male (61% males). There were no significant differences in GCS, AIS, and ISS between pre and post pathway groups. Post pathway implementation saw reduced use of cervical spine CT, although this was not clinically significant (33% vs 31%, p = 0.74). However, cervical spine radiography use increased (9% vs 16%, p = 0.03), and there was also an increase in screening for BCVI injuries with higher use of CTA (5% vs 7%, p = 0.52). A total of 12 CSI and 3 BCVI were identified with no missed injuries. Provider adherence to the pathway was modest (54%). Conclusion Implementation of a combined CSI/BCVI clinical pathway for pediatric trauma patients increased screening radiography and did not miss any injuries. However, CT use did not significantly decrease and provider adherence was modest, supporting the need for further implementation analysis and larger studies to validate the pathway's sensitivity and specificity for CSI/BCVI.

Thoracic and lumbar spine pedicle morphology in Japanese patients.

Pedicle morphology is important for intraoperative surgical anatomy and to define pedicle screw design and parameters. However, differences of pedicle size according to ethnicity and gender are not well studied. The purpose of this study is to investigate morphological characteristics of the pedicle in Japanese patients for determining adequate screw size and optimal surgical planning. We investigated thoracic and lumbar pedicle morphology in Japanese patients using computed tomography (CT) measurements and analyzed the standard size of pedicles on upper thoracic to lumbar spine CT images in 227 Japanese patients. Gender had a larger impact on the shape and size of pedicles than racial differences. In the distribution of pedicle width, we calculated the ratio of values less than 4.5mm, that in females resulted to be over 30% for the Th3-Th9 segment, and particularly high, above 60% at Th4 and Th5. Our measurement analysis showed that pedicle morphological parameters in Japanese patients showed tendency to be smaller to those found in other studies, and particularly in female patients, they were statistically significantly smaller. Adequate transpedicular instrumentation for Japanese patients will require smaller size pedicle-related devices that will match our anatomical findings to achieve safe device placement. In addition, serving ethnically non-homogenous patient population can require further to spinal morphometric for precise device selection.

CT scans for pediatric injury in a middle-income country trauma center: Are we repeating past mistakes?

PurposeSustained efforts in high-income countries have decreased the rate of unnecessary computed tomography (CT) among children, aiming to minimize radiation exposure. There are little data regarding CT use for pediatric trauma in low- and middle-income countries. We aimed to assess the pattern and utility of CT performed during evaluation of trauma patients presenting to a middle-income country (MIC) trauma center. MethodsWe reviewed pediatric (age<18) trauma admissions at a single tertiary referral center in South Africa. Patient demographics, injury details, surgical intervention(s), and mortality were abstracted from the medical record. CT indications, results, and necessity were determined by review. ResultsOf 1,630 children admitted to the trauma center, 826 (51%) had CT imaging. Children undergoing imaging were younger (median age 11 [IQR: 6, 16] vs 13 [IQR: 7, 17]) and had higher median ISS [9 [IQR: 4, 13] vs 4 [2, 9]) compared to those without imaging (both p<0.001). Overall, 1,224 scans were performed with normal findings in 609 (50%). A median of 1 scan was performed per patient (range: 1–5). The most common location was CT head (n = 695, 57%). Among patients with positive findings on CT head (n = 443), 31 (7%) underwent either intracranial pressure monitoring or surgery. CT of the cervical spine had positive findings in 12 (7%) with no patients undergoing spine surgery. Of 173 patients with abdominal CT imaging, 83 (48%) had abnormal findings and 18 (10%) required operative exploration. Thirteen (16%) patients with abnormal findings on abdominal CT had exploratory laparotomy. Of 111 children undergoing whole body CT, 8 (7%) underwent thoracic and/or abdominal operations. ConclusionUse of CT during evaluation of pediatric trauma is common in an MIC center. A high rate of normal findings and low rates of intervention following head, cervical spine, and abdominal CT suggest potential overuse of this resource. Level of EvidenceLevel III

Acquired Chiari Type 1 Malformation Secondary to Paget’s Disease of the Bone: A Case Report

Chiari type 1 malformations are characterised by caudal descent of cerebellar tonsil into foramen magnum. Usually it is congenital. Paget’s disease causing acquired chiari type 1 malformation is rare with only five reported cases in the literature. The diagnosis is primarily by Magnetic Resonance Imaging (MRI). Authors reported a case of acquired chiari type 1 malformation due to paget’s disease in a 58-year-old male patient diagnosed by MRI and Computed Tomography (CT). The patient presented with complaints of headache, unsteady gait, slow movements with weakness in all the four limbs, difficulty in walking which aggravated since three days and stammering of speech. Initially a diagnosis of motor neuron disease was suspected and the patient was subjected for MRI examination of brain and spine. MRI revealed platybasia with cerebellar tonsillar herniation with calvarial thickening and multiple vertebral collapse. The CT of brain and spine was done to evaluate bones specifically in view of thickened cranial vault and multiple vertebral collapse on MRI which revealed features of paget’s disease in the form of widened sclerotic bone with lytic areas and thickened trabeculae. Hence, diagnosis of paget’s disease causing acquired chiari type 1 malformation was made which correlated with biochemical findings. The management is different in primary and acquired chiari type 1 malformation and hence it is important to diagnose this condition which is relatively rare.

Diagnostic Accuracy and Prognostic Significance of Point-Of-Care Ultrasound (POCUS) for Traumatic Cervical Spine in Emergency care setting: A Comparison of clinical outcomes between POCUS and Computed Tomography on a Cohort of 284 Cases and Review of Literature.

Background:The cervical spine is injured in approximately 3% of major trauma patients, and 10% of patients with serious head injury. Therefore, clearance of the cervical spine in multitrauma patients is a critically important task. This is particularly important, considering that there is a positive correlation between a Glasgow Coma Scale of <14 and cervical spine injury. Radiography is not sensitive enough to rule out cervical spine injury, especially as radiography done in the trauma setting is usually technically unsatisfactory.Objective:The current study aims to assess the diagnostic accuracy and prognostic significance of using bedside point-of-care ultrasound (POCUS) in traumatic cervical spine injuries compared to computed tomography (CT) as the reference standard.Materials and Methods:This comparative study enrolled 284 patients with severe multiple trauma at a tertiary care center between July 2017 and March 2020. The inclusion criteria included an indication of cervical spine CT scan, satisfaction of patients with participation in the study, and the lack of history of injury and severe traumatic events. The exclusion criteria were the history of a previous cervical spinal trauma, spondylosis, scoliosis, spinal tuberculosis, degenerative vertebral changes, and patients who refused to give consent to participate in research or CT scanning. The data were analyzed by SPSS software, and sensitivity, specificity, and positive predictive value (PPV)/negative predictive value (NPV) were determined based on CT findings.Results:The best window for the cervical spine was through the anterior triangle using the linear array probe (6–13 MHz). POCUS had a sensitivity of 78.5%, specificity of 98.4%, PPV of 93.2%, NPV of 92.8%, and accuracy of 93.2% in detecting all types of spinal injuries in comparison with CT scan as the standard modality. POCUS had a sensitivity of 100%, specificity of 92.3%, PPV of 62.3%, NPV of 100%, and accuracy of 91.7% in cases with the movement of injured particles. POCUS had a sensitivity of 32.2%, specificity of 100%, PPV of 100%, NPV of 91.4%, and accuracy of 90.8% in detecting the fracture of transverse process. POCUS had a sensitivity of 36.1%, specificity of 100%, PPV of 100%, NPV of 98.1%, and accuracy of 98.4% in ≤14-year age multitrauma patients. In comparison, the current study achieved a sensitivity of 79.4%, specificity of 95.7%, PPV of 92.1%, NPV of 86.3%, and accuracy of 88.6% in >14-year age multitrauma patients.Conclusion:POCUS for cervical spine is feasible using portable ultrasound machine and by neurosurgeons/radiologists/emergency physicians with basic training. It holds great potential in resource-starved settings and in unstable patients for ruling out unstable cervical spine injuries and injuries associated with the movement of fractured or dislocated particles. POCUS examination of the cervical spine was possible in the emergency setting and even in unstable patients and could be done without moving the neck. Future studies, ideally conducted as randomized control trials, are required to establish training and education standards, and to assess the feasibility and safety of POCUS as an alternative to radiography.

Part 4. Clinical Practice Guideline for Surveillance and Imaging Studies of Trauma Patients in the Trauma Bay from the Korean Society of Traumatology

The following recommendations are presented herein: All trauma patients admitted to the resuscitation room should be constantly (or periodically) monitored for parameters such as blood pressure, heart rate, respiratory rate, oxygen saturation, body temperature, electrocardiography, Glasgow Coma Scale, and pupil ref lex (1C). Chest AP and pelvic AP should be performed as the standard initial trauma series for severe trauma patients (1B). In patients with severe hemodynamically unstable trauma, it is recommended to perform extended focused assessment with sonography for trauma (eFAST) as an initial examination (1B). In hemodynamically stable trauma patients, eFAST can be considered as the initial examination (2B). For the diagnosis of suspected head trauma patients, brain computed tomography (CT) should be performed as an initial examination (1B). Cervical spine CT should be performed as an initial imaging test for patients with suspected cervical spine injury (1C). It is not necessary to perform chest CT as an initial examination in all patients with suspected chest injury, but in cases of suspected vascular injury in patients with thoracic or high-energy damage due to the mechanism of injury, chest CT can be considered for patients in a hemodynamically stable condition (2B). CT of the abdomen is recommended for patients suspected of abdominal trauma with stable vital signs (1B). CT of the abdomen should be considered for suspected pelvic trauma patients with stable vital signs (2B). Whole-body CT can be considered in patients with suspicion of severe trauma with stable vital signs (2B). Magnetic resonance imaging can be considered in hemodynamically stable trauma patients with suspected spinal cord injuries (2B).

Workload for radiologists during on-call hours: dramatic increase in the past 15\xa0years

BackgroundThe objective of this study is to investigate the workload for radiologists during on-call hours and to quantify the 15-year trend in a large general hospital in Western Europe.MethodsData regarding the number of X-ray, ultrasound and computed tomography (CT) studies during on-call hours (weekdays between 6.00 p.m. and 7.00 a.m., weekends, and national holidays) between 2006 and 2020 were extracted from the picture archiving and communication system. All studies were converted into relative value units (RVUs) to estimate the on-call workload. The Mann–Kendall test was performed to assess the temporal trend.ResultsThe total RVUs during on-call hours showed a significant increase between 2006 and 2020 (Kendall's tau-b = 0.657, p = 0.001). The overall workload in terms of RVUs during on-call hours has quadrupled. The number of X-ray studies significantly decreased (Kendall's tau-b = − 0.433, p = 0.026), whereas the number of CT studies significantly increased (Kendall's tau-b = 0.875, p < 0.001) between 2006 and 2020. CT studies which increased by more than 500% between 2006 and 2020 are CT for head trauma, brain CTA, brain CTV, chest CT (for suspected pulmonary embolism), spinal CT, neck CT, pelvic CT, and CT for suspected aortic dissection. The number of ultrasound studies did not change significantly (Kendall's tau-b = 0.202, p = 0.298).ConclusionsThe workload for radiologists during on-call hours increased dramatically in the past 15 years. The growing amount of CT studies is responsible for this increase. Radiologist and technician workforce should be matched to this ongoing increasing trend to avoid potential burn-out and to maintain quality and safety of radiological care.

EVALUATION OF IRRADIATION DOSES DELIVERED TO PATIENTS IN COMPUTED TOMOGRAPHY EXAMINATIONS IN 10 RADIOLOGY DEPARTMENTS IN DOUALA-CAMEROON.

Computed tomography (CT) scan is currently the most irradiating radio diagnostic procedure for the patients. The effective dose delivered by a CT-scan exploration corresponds to 1-20years of natural irradiation of an individual. Hence, there is need to evaluate this medical exposure, in order to provide indicators and propose guidelines for its daily practice. The purpose of this work was to assess patient exposure levels due to CT-scan exams and propose a local diagnostic reference levels for the most common CT examinations performed in the radiology units of Douala/Cameroon. Data from 1775 CT scans, amongst which 10 different types of common CT examinations on adults and children, were collected, of which 1378 were adult CT scans and 397 were pediatric CT scans. The dose-length product (DLP) values in the adult population for head, abdomen-pelvic and lumber spine CT scans were high as compared to the Institute for Radiological Protection and Nuclear Safety recommendations and previous local DRL with an increase of 36, 15 and 23%, respectively. A general decrease of the DLP for CT-scans examinations in the pediatric population was observed.

Usefulness of model-based iterative reconstruction in low-dose lumbar spine CT after spine surgery with metal implant: a phantom study.

The major problems of computed tomography (CT) imaging include radiation exposure and severe artifacts caused by operative implants. To evaluate the usefulness of the metal artifact reduction algorithm and model-based iterative reconstruction (MBIR) in postoperative low-dose (LD) spine CT. A CT torso phantom was scanned at standard-dose (SD) and LD settings. The CT images were reconstructed by three methods: hybrid iterative reconstruction (HIR); metal artifact reduction; and MBIR. The radiation dose of the phantom imaging was evaluated by volume CT dose index (mGy), dose length product (DLP, mGy × cm), and effective dose (mSv). The image quality of the six images was visually evaluated and analyzed using Scheffe's paired comparison method. The average preference of each method was calculated based on the comparative scores. The task transfer function (TTF) and noise power spectrum for HIR and MBIR were also measured. The respective radiation-dose-related parameters of the SD and LD conditions were: volume CT dose index = 10.2 and 1.2 mGy; DLP = 277.9 and 33.9 mGy × cm; and effective dose = 4.2 and 0.5 mSv. The average preference for diagnostic acceptability of MBIR at LD was not significantly different from the other reconstructions of SD data. MBIR successfully reduced metal artifacts in the LD condition. The 10% TTF was higher for HIR at SD and higher for MBIR at LD. MBIR is useful for LD spine CT after spine surgery with metal implant.

Can Diffuse Idiopathic Skeletal Hyperostosis Be Diagnosed by Plain Lumbar Spine X-Ray Findings Alone?

Study Design:Retrospective case-control studyObjectives:To determine whether diffuse idiopathic skeletal hyperostosis (DISH) can be diagnosed based on anterior longitudinal ligamental ossification in the lumbar spine using plain lumbar spine X-ray images.Methods:This study included 100 patients (59 men and 41 women; mean age, 64.8 ± 13.8 years; range, 27-89 years) who underwent computed tomography (CT) of the chest to the pelvis in our hospital and plain lumbar spine radiography within 6 months before and after CT scanning. DISH was diagnosed based on the thoracolumbar spine CT findings using Resnick’s diagnostic criteria. The patients were grouped according to DISH diagnosis into the DISH (+) and DISH (−) groups. On the frontal and lateral lumbar spine X-ray images, each spinal level from Th11/12 to L5/S was scored based on the Mata scoring system. The distribution of the Mata scores was compared between the 2 groups.Results:Forty (40%) patients were diagnosed with DISH based on the CT findings. A cutoff value ≥8 provided a sensitivity of 75% and specificity of 100% for diagnosing DISH, thus, indicating the validity of the cutoff value. In the DISH (−) group, no patient had ≥3 consecutive spinal levels with a Mata score ≥2, suggesting that DISH can be diagnosed on the basis of at least 3 consecutive spinal levels with a Mata score ≥2.Conclusion:On lumbar spine X-ray images of the T11/12 to L5/S levels, a Mata score ≥2 for at least 3 consecutive levels or a total score ≥8 strongly indicates the presence of DISH.

Patient Radiation Exposure Associated With the Use of Computer Navigation During Spinal Fusion.

Calibration of computer navigation for spinal fusion is most commonly conducted using either a preoperative computed tomography (CT) scan or intraoperative O-arm scanning. This study aimed to directly compare patient radiation exposure from intraoperative O-arm use for pedicle screw placement versus typical diagnostic lumbar spine CT studies. A retrospective review of patients undergoing O-arm navigated lumbar spine fusion procedures was performed to record radiation exposure as the primary outcome, as well as surgical and demographic details. The same was done for a control group of patients undergoing lumbar spine CT scans. A total of 83 patients undergoing lumbar spine fusion with O-arm navigation were included, as well as 105 unique patients who underwent a lumbar spine CT. The 2 groups were similar in terms of average age (60.2 versus 60.5, P = .90), average height (170 cm versus 169 cm, P = .50), and average weight (92.6 kg versus 90.9 kg, P = .62). Dose-length product for O-arm navigated procedures was 798.3 mGy-cm and 924.2 mGy-cm for CT scans (P = .064). Subgroup analysis revealed 18 patients who had both an O-arm navigated surgery and a lumbar spine CT. In this group the average dose-length product for O-arm surgeries was 806.2 mGy-cm and 822.1 mGy-cm for CT scans (P = .92) CONCLUSION: This study revealed no statistically or clinically significant differences between patient radiation exposure for O-arm operative navigation compared to lumbar spine CT. Given the similarity in radiation exposure, surgeons should rely on other factors to guide decision making in regard to mode of imaging for navigation. Knowledge of this comparison and total radiation exposure will also be useful for patient education and shared decision making in regard to navigated procedures.

Morphological Differences Between the Pedicles in Nondystrophic Scoliosis Secondary to Neurofibromatosis Type 1 and Those in Adolescent Idiopathic Scoliosis

To compare the pedicle morphology of nondystrophic scoliosis secondary to neurofibromatosis type 1 (ND-NF1) scoliosis secondary to neurofibromatosis type 1 (NF1-S) and adolescent idiopathic scoliosis (AIS) using computed tomography (CT) in a consistent classification system. The transverse pedicle widths of cancellous and cortical channels were measured using preoperative spinal CT images (T1-L5) and then classified as having type A-E pedicles; type B, C, D, and E pedicles were regarded as abnormal. A subset of these patients, a postoperative CT was performed to evaluate the accuracy of pedicle screw placement. According to the perforation of the medial or lateral pedicle walls by the pedicle screw, the placement of screw was classified by a grade ranging from 0 to 3, and grades 2 and 3 were regarded as misplacement. In total, 3230 pedicles were measured and classified, and the incidence rate of abnormal pedicles in the ND-NF1 group was significantly greater than that of the AIS group (65.9% vs. 61.4%, P= 0.03). The misplacement rate in the ND-NF1 group was significantly greater than that in the AIS group (12.2% vs. 7.4%; P=0.01), and in terms of the corresponding 1100 pedicles, the incidence rate of abnormal pedicles in the ND-NF1 group was higher than that in the AIS group (71.7% vs. 64.9%; P= 0.02). The incidence rate of abnormal pedicles in patients with ND-NF1 is significantly greater than that of patients with AIS, and it may the reason for the higher misplacement rate of pedicle screws in patients with ND-NF1.

Improvement of image quality and diagnostic confidence using Smart MAR - a projection-based CT protocol in patients with orthopedic metallic implants in hip, spine, and shoulder.

In computed tomography (CT) scans, artifacts caused by metallic orthopedic implants still hamper the visualization of important, periprosthetic tissues. Smart MAR metal artifact reduction tool is a promising three-stage, projection-based, post-processing algorithm. To determine whether the Smart MAR tool improves subjective and objective image quality and diagnostic confidence in patients with orthopedic implants of the hip, spine, and shoulder. Seventy-two patients with orthopedic screws, hip/shoulder replacement, or spine spondylodesis were included. CT scans were performed on a single-source multislice CT scanner, raw data were post-processed using Smart MAR. Image quality was evaluated both quantitatively (ROI-based) and qualitatively (rater-based) and compared to iterative reconstructions (ASIR V). As comparative standard for artificial prosthetic breaks or loosening, follow-up examinations were used. Smart MAR reconstructions of the hip (n = 23), spine (n = 26), and shoulder (n = 23) showed a significantly reduced attenuation and noise of regions adjacent to metallic implants (P<0.002). Subjective image quality (P<0.005, shoulder P = 0.038/P = 0.046) and overall diagnostic confidence were higher in Smart MAR (all regions P<0.002). Signal-to-noise ratio (SNR; P = 0.72/P = 0.96) was not improved. Compared to standard ASIR V new, artificial metal extinctions (up to 50%) or periprosthetic hem lines (48%-73%) were introduced by Smart MAR. Smart MAR improved image quality of the hip, spine, and shoulder CT scans resulting in higher diagnostic confidence in evaluation of periprosthetic soft tissues. As shown for spine implants, it should be used with caution and as a complementary tool for evaluation of periprosthetic loosening or integrity of metal implant, as in many cases it introduced new artifacts.