Computed Tomography Group Research Articles

Ischemic stroke lesion detection, characterization and classification in CT images with optimal features selection.

Ischemic stroke is the dominant disorder for mortality and morbidity. For immediate diagnosis and treatment plan of ischemic stroke, computed tomography (CT) images are used. This paper proposes a histogram bin based novel algorithm to segment the ischemic stroke lesion using CT and optimal feature group selection to classify normal and abnormal regions. Steps followed are pre-processing, segmentation, extracting texture features, feature ranking, feature grouping, classification and optimal feature group (FG) selection. The first order features, gray level run length matrix features, gray level co-occurrence matrix features and Hu's moment features are extracted. Classification is done using logistic regression (LR), support vector machine classifier (SVMC), random forest classifier (RFC) and neural network classifier (NNC). This proposed approach effectively detects ischemic stroke lesion with a classification accuracy of 88.77%, 97.86%, 99.79% and 99.79% obtained by the LR, SVMC, RFC and NNC when FG12 is opted, which is validated by fourfold cross validation.

How reliable are imaging techniques in aging males with bladder cancer?

Introduction The aim of this study was to evaluate consistency between clinical lymph node positivity and pathological lymph node positivity in patients undergoing open radical cystectomy and pelvic lymph node dissection due to bladder cancer. Material and method A total of 135 patients who had open radical cystectomy, extended lymph node dissection, and clear preoperative contrast-enhanced abdominopelvic computed tomography (CT) or magnetic resonance imaging (MRI) images were included in the study. Positive clinical lymph nodes and positive pathological lymph nodeswere recorded. The largest positive clinical and pathological lymph nodeswere recorded. In terms of clinical lymph node involvement, compatibility between radiological findings and pathological results was evaluated. Results In the CT group, the sensitivity was 25.81%, specificity was 95.45%, positive predictive value (PPV) was 66.67%, negative predictive value (NPV) was 78.50%, and accuracy was 77.31%. In the MRI group, the sensitivity was 50.00%, specificity was 100%, PPV was 100%, NPV was 76.92%, and accuracy was 81.25%. For consistency between pathological lymph nodes and clinical lymph nodes according to the imaging type, there was no statistically significant difference in the sensitivity, specificity, NPV, and accuracy rates between the imaging techniques (p > 0.05). However, the PPV was significantly higher in the MRI group than the CT group (100% vs.66.67%, respectively; p = 0.014). Conclusion Positive lymph nodes play a critical role in the prognosis of patients with bladder cancer and the sensitivity of contrast-enhanced abdominopelvic CT and MRI used routinely in clinical practice is low in lymph node detection. MRI seems more reliable than CT in lymph node detection.

Routine versus selective computed tomography in non-traumatic acute abdominal pain: meta-analysis of randomised trials.

To compare the routine vs. selective use of computed tomography (CT) in patients presenting with non-traumatic acute abdominal pain (AAP) to a surgical service. We conducted a systematic review of literature and meta-analysis of outcomes according to PRISMA statement standards to compare the routine vs. selective use of CT in adult patients presenting with non-traumatic AAP. Analysis of 722 patients from 4 randomised controlled trials showed no difference between the routine CT and selective CT groups in terms of proportion of correct diagnoses (OR 1.36,95% CI 0.89, 2.07, P = 0.15), mortality (RD 0.03, 95% CI - 0.08, 0.02, P = 0.27] and length of hospital stay (LOS) [MD - 0.26, 95% CI - 2.07, 1.55, P = 0.78). The routine use of CT does not improve the proportion of correct diagnoses and mortality compared to selective use of CT in adult patients with non-traumatic AAP. The available evidence regarding the influence of routine CT on LOS may be subject to type 2 error. These findings, however, may not apply to the elderly patient with AAP and further studies are required.

The clinical utility of fluoroscopic versus CT guided percutaneous transpedicular core needle biopsy for spinal infections and tumours: a randomized trial

Biopsy is important to obtain microbiological and histopathological diagnosis in spine infections and tumors. To date, there have been no prospective randomized trials comparing fluoroscopic guided and computed tomography (CT) transpedicular biopsy techniques. The goal of this study was to evaluate the accuracy, safety, and diagnostic outcome of these two diagnostic techniques. To evaluate the accuracy, safety, and diagnostic outcome of fluoroscopic guided and CT transpedicular biopsy techniques. Prospective randomized trial. Sixty consecutive patients with clinical symptoms and radiological features suggestive of spinal infection or malignancy were recruited and randomized into fluoroscopic or CT guided spinal biopsy groups. Both groups were similar in terms of patient demographics, distribution of spinal infections and malignancy cases, and the level of biopsies. The primary outcome measure was diagnostic accuracy of both methods, determined based on true positive, true negative, false positive, and false negative biopsy findings. Secondary outcome measures included radiation exposure to patients and doctors, complications, and postbiopsy pain score. A transpedicular approach was performed with an 8G core biopsy needle. Specimens were sent for histopathological and microbiological examinations. Diagnosis was made based on biopsy results, clinical criteria and monitoring of disease progression during a 6-month follow up duration. Clinical criteria included presence of risk factors, level of inflammatory markers and magnetic resonance imaging findings. Radiation exposure to patients and doctors was measured with dosimeters. There was no significant difference between the diagnostic accuracy of fluoroscopic and CT guided spinal biopsy (p=0.67) or between the diagnostic accuracy of spinal infection and spinal tumor in both groups (p=0.402 for fluoroscopy group and p=0.223 for CT group). Radiation exposure to patients was approximately 26 times higher in the CT group. Radiation exposure to doctors in the CT group was approximately 2 times higher compared to the fluoroscopic group if a lead shield was not used. Lead shields significantly reduced radiation exposure to doctors anywhere from 2 to 8 times. No complications were observed for either group and the differences in postbiopsy pain scores were not significant. The accuracy, procedure time, complication rate and pain score for both groups were similar. However, radiation exposure to patients and doctors were significantly higher in the CT group without lead protection. With lead protection, radiation to doctors reduced significantly.

Prospective investigation of pain associated with ultrasound- and computed tomography-guided percutaneous biopsies in oncological patients

AimsThe present study aims to investigate the pain, anxiety and other factors that are associated with percutaneous computed tomography (CT)- and ultrasound (US)-guided biopsies of tumors.Material and MethodsThe study prospectively included 60 consecutive patients, of which 24 underwent CT-guided biopsies and 36 US-guided biopsies. The location of targeted tumors was within the thorax, abdomen, pelvis, and limbs. A questionnaire containing numerical rate scales (0-10) regarding procedural and post-procedural pain, anxiety, and other associated parameters was filled out by each patient 2-6 hours after the procedure. CT and ultrasound parameters were compared. The two groups were then pooled together in order to compare pain scores per targeted organ and to analyze the parameters that were associated with pain.ResultsThere was no significant difference between the CT and US group with the exception of the positional discomfort, which was higher in the CT group (p=0.003). The average procedural pain score (2.0) was significantly higher than the post-procedural pain (1.3, p=0.006) and the phlebotomy pain (0.8, p<0.0001). There was no significant difference between the targeted organs with regards to the pain score. The factors that showed a positive correlation with the procedural pain were procedure-related anxiety (p=0.005), positional discomfort (p=0.01), and phlebotomy pain (p=0.0008). The pre interventional use of an analgesic was negatively correlated with the procedural pain (p=0.02).ConclusionsCT- and US- guided percutaneous biopsies are associated with low levels of pain that are generally well tolerated by patients irrespective of the targeted organ.

Paraspinal muscle changes after single-level posterior lumbar fusion: volumetric analyses and literature review

BackgroundPosterior lumbar fusion is a widely accepted surgical technique; however, it has been related to the possibility of paraspinal muscle atrophy after surgery. We investigated 1-year postoperative changes in paraspinal muscle volume using a simple formula applicable to magnetic resonance imaging (MRI) or computed tomography (CT) images.MethodsPatients with degenerative lumbar spinal stenosis who underwent posterior interbody fusion (PLIF) at the L4/5 level in the period from May 2010 to June 2017 were enrolled in this study. Radiologic parameters were measured using MRI or CT images which were taken before surgery and at 1 year after surgery. The volume of the paraspinal muscles was calculated using a simple formula which was derived from the formula for calculating the volume of truncated elliptic cones.ResultsA total of 40 patients were included; 24 were analyzed using MRI and 16 were analyzed using CT. The mean age of the patients was 59.6 ± 12.1 years and 32 (80.5%) were female. When comparing the preoperative and 1-year-postoperative images, multifidus muscle (MF) reduction was consistently observed in the MRI and CT groups, right and left (p = 0.003, p < 0.001, p = 0.005 and p < 0.001, respectively). In the erector spinae (ES) group, decrease in muscle volume was observed in the right-sided muscles of the CT group (p < 0.001), but no significant change was observed in the MRI group. The psoas muscle showed no significant change after 1 year. Conversely, regression analysis showed a negative correlation between MF muscle volume loss and age in the MRI group (right and left, p = 0.002 and p = 0.015, respectively), that is, the younger the age, the greater loss of muscle mass.ConclusionAfter the posterior lumbar fusion, the volume of the MF muscles was markedly decreased, and the degree of decrease was apparent in the MRI. The volume of the ES muscles, which are located relatively laterally, also tended to decrease at 1 year after surgery.

Clinical application of CT measurement in primary total hip arthroplasty of DDH patients

Objective To investigate the clinical effect of preoperative computed tomography (CT) measurement of acetabulum femoral neck combined anteversion in primary total hip arthroplasty (THA). Methods From March 2016 to may 2018, 48 patients (90 hips) with developmental dysplasia of the hip (DDH) who were treated with THA in the orthopaedic department of Jiangmen Central Hospital were measured by X-ray and spiral CT three-dimensional reconstruction technology before operation, and the best combined anteversion angle of acetabulum was determined before implementing THA, which was CT group; the remaining 42 patients were not measured by CT before operation, which was X-ray group. The difference of acetabulum cup anteversion angle, acetabulum femoral neck combined anteversion angle and preoperation angle were evaluated by three-dimensional computed tomography (3D-CT) in CT group. Results There was no significant difference in operative time, intraoperative blood loss, time of getting out of bed and length of lower limbs between the two groups (P>0.05). In CT group, the acetabulum cup anteversion and acetabulum femoral neck anteversion were close to the pre-operative angle at 2 and 3 months postoperatively (P>0.05). The Harris hip score of CT group was significantly higher than that of X-ray group at 2 and 3 months after operation, and the incidence of deep vein thrombosis was 6.25%, significantly lower than that of X-ray group (21.43%) (P 0.05). Conclusions For DDH patients who received THA for the first time, preoperative CT measurement of acetabulum femoral neck combined with anteversion is conducive to the formulation of the best combined anteversion adjustment scheme, which can obtain the maximum initial stability, improve the surgical effect and reduce the occurrence of dislocation of prosthesis. Key words: Tomography, X-ray computed; Acetabulum; Femur neck; Hip dysplasia; Arthroplasty, replacement, hip

Inter-imaging accuracy of computed tomography, magnetic resonance imaging, and transrectal ultrasound in measuring prostate volume compared to the anatomic prostatic weight.

To evaluate the accuracy of transrectal ultrasound (TRUS), computed tomography (CT), and magnetic resonance imaging (MRI) compared to the reference standard of the post-surgical anatomic prostatic weight (APW). A total of 349 patients from two institutions were included. The CT and MRI dimensions, and TRUS-reported prostate volumes (PV) were obtained. The prolate ellipsoid formula was used to calculate PV. Cross-sectional measurements were evaluated and compared to the reported post-surgical pathology measurements and calculated pathology volume (path PV). A basic statistical analysis was performed using the Pearson correlation, Bland-Altman analysis, and Passing-Bablok regression. A total of 198 patients were included in the MRI group, 118 in the CT group, 295 in the TRUS group, and 51 in the all-inclusive common cohort. The MRI PV demonstrated a good to excellent correlation with the APW (r=0.79). The CT PV demonstrated a good correlation with APW (r=0.78). The TRUS PV showed a correlation with APW (r=0.67). The correlations identified in each individual group held true in the common cohort as well. The path PV showed an excellent correlation with APW (r=0.87), followed by MRI PV (r=0.81), then CT PV (r=0.73), and lastly TRUS PV (r=0.71). MRI and CT are equally effective in assessing the PV, and they can be readily utilized to guide the benign prostatic hyperplasia (BPH) management without repeating in-office TRUS. This is not only cost-effective, but also eliminates patient anxiety and discomfort.

Computed tomography-based diagnosis of occult fragility hip fractures offer shorter waiting times with no inadvertent missed diagnosis.

Surgical delay due to the wait for advanced cross-sectional imaging in occult fragility hip fracture management is not well studied. Our study aims to investigate computed tomography (CT) as an alternative to the gold standard magnetic resonance imaging (MRI) in occult hip fracture workup to decrease surgical delay. We conducted a retrospective review of all CTs and MRIs performed between 2015 and 2017 for patients with clinically suspected fragility hip fractures and negative plain radiographs to investigate surgical delay resulting from the wait for advanced imaging and representations due to missed fractures. A total of 243 scans (42 CTs and 201 MRIs) were performed for occult hip fracture workup over the study timeframe, of which 49 patients (20%) had occult hip fractures [CT: 6 (14%), MRI: 43 (21%), p = 0.296)]. There were no readmissions for fracture in the 12 months following a negative scan. The CT group had shorter waiting times (CT: 29 ± 24 h, MRI: 44 ± 32 h, p = 0.004) without significantly reducing surgical delay (CT: 82 ± 36 h, MRI: 128 ± 58 h, p = 0.196). The MRI group had a higher number of patients with a cancer history (p = 0.036), reflective of the practice for workup of possible metastases as a secondary intention. Advanced cross-sectional imaging wait times in occult hip fracture workup contribute significantly to surgical delay. Modern CT techniques are not inferior to MRI in detecting occult fractures and may be a suitable alternative in the absence of a cancer history if MRI cannot be obtained in a timely fashion or is contraindicated. Clinicians should utilize the more readily available imaging modality to reduce surgical delay.

Risk of post-contrast acute kidney injury in emergency department patients with sepsis

Although computed tomography (CT) is a useful tool for exploring occult infection in patients with sepsis in the emergency department, the potential nephrotoxicity of contrast media is a major concern. Our study aimed to investigate the association between use of contrast-enhanced CT and the risks of acute kidney injury and other adverse outcomes in patients with sepsis. In total, 587 patients with sepsis who underwent CT scan (enhanced CT group: 105, non-enhanced CT group: 482) from January 2012 to December 2016 at a tertiary referral centre were enrolled in this retrospective analysis, and propensity score matching was performed to minimise the selection bias. The length of stay, incidences of acute kidney injury and emergent dialysis, and short-term mortality were compared between the two groups. Compared with patients in the non-enhanced CT group, patients in the contrast-enhanced CT group did not have increased risks of acute kidney injury (odds ratio [OR]=1.38, 95% confidence interval [CI]=0.55-3.43; P=0.489), emergent dialysis (OR=1.31, 95% CI=0.47-3.68; P=0.602), or short-term mortality (OR=0.90, 95% CI=0.48-1.69; P=0.751). In addition, there was no significant difference in the median length of hospital stay between survivors in the two groups (20 vs 19 days, P=0.742). Intravenous contrast administration during CT scanning was not associated with prolonged length of hospital stay in patients with sepsis in an emergency setting. Moreover, the use of contrast-enhanced CT was not associated with increased risks of acute kidney injury, emergent dialysis, or short-term mortality.

Templating in shoulder arthroplasty - A comparison of 2D CT to 3D CT planning software: A systematic review.

Computed tomography (CT) utilizing computer software technology to generate three-dimensional (3D) rendering of the glenoid has become the preferred method for preoperative planning. It remains largely unknown what benefits this software may have to the intraoperative placement of the components and patient outcomes. The purpose of this systematic review is to compare 2D CT to 3D CT planning in total shoulder arthroplasty. Systematic review. A systematic database search was conducted for relevant studies evaluating the role of 3D CT planning in total shoulder arthroplasty. The primary outcome was component placement variability, and the secondary outcomes were intra- and inter-observer reliability in the context of preoperative planning. Following title-abstract and full-text screening, six eligible studies were included in the review (n = 237). The variability in glenoid measurements between 3D CT and 2D CT planning ranged from no significant difference to a 5° difference in version and 1.7° difference in inclination (p<0.05). Posterior bone loss was underestimated in 52% of the 2D measured patients relative to 3D CT groups. Irrespective of 2D and 3D planning (39% and 43% of cases respectively), surgeons elected to implant larger components than those templated. There was no literature identified comparing differences in time, cost, functional outcomes, complications, or patient satisfaction. The paucity of evidence exploring clinical parameters makes it difficult to comment on clinical outcomes using different methods of templating. More studies are required to identify how improved radiographic outcomes translate into improvements that are clinically meaningful to patients.

Measurement of Skull Size on Computed Tomography Images for Developing a Bone Conduction Headset Suitable for the Korean Standard Head Size.

Background and ObjectivesWe aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement.Subjects and MethodsWe reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement.ResultsAll the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). ConclusionsOur findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

P2836Role of pre-procedural CT-imaging on catheter ablation in patients with atrial fibrillation: procedural outcomes and radiological exposure

Abstract Introduction Cardiac computerized tomography (CT) is commonly used to study left atrial (LA) and pulmonary veins (PVs) anatomy before atrial fibrillation (AF) ablation. However, it remains unclear whether pre-procedural imaging actually is associated with an improvement of efficiency, efficacy, and safety. Purpose Aim of the the study was to determine the impact of pre-procedural imaging using CT with 3-D reconstruction on procedural outcomes and radiological exposure in patients who undergo radiofrequency catheter ablation (RFA) to eliminate AF. Methods In this registry, 493 consecutive patients (age 62±8 years, 70% male) with paroxysmal (316) or persistent (177) AF who underwent RFA were included. A CT scan was obtained in 324 (66%) patients (CT Group) prior to RFA, while 169 (34%) didn't have any pre-procedural imaging (No-CT Group). Antral PVs isolation was performed in all patients along using an open-irrigation-tip catheter with a 3-D electroanatomical navigation system. Additional ablation applications were targeted if required. Procedural outcome, including radiological exposure, and clinical outcomes were compared among patients who underwent RFA with (CT-Group) and without (No CT-Group) pre-procedural imaging. Results Acute PV isolation was obtained in all patients. Additional ablation targets were targeted along the CTI (71/324 [22%] vs. 40/169 [24%], P=NS), the roof line (74/324 [23%] vs. 40/169 [24%], P=NS), the mitral isthmus (33/324 [10%] vs. 12/169 [7%], P=NS) and CFAEs (28/324 [8.6%] vs. 12/169 [7.1%], P=NS), without significant differences among groups. Complication rate were comparable between CT and No CT patients (4.3% vs 3%, P=0.7). In one Redo procedure of the No-CT Group, for the impossibility of identifying left PVs, a 3D LA fluoro-angiography was performed, which confirmed a left PVs occlusion. (Figure) No differences were observed about mean duration of the procedure (231±60 vs 233±58 min, P=0.7) and fluoroscopy time (13±10 vs 13±8 min, P=0.6) between groups. Cumulative radiation dose resulted significantly higher in the CT-Group (8.9±24 vs 4.8±15 mSV, P=0.02). Compared to paroxistical AF, persistent AF patients showed a comparable procedural-ED (6.6±26 vs 6±19, P=0.8) but with an higher CT-ED (1.7±2.9 vs 1.1±1.9, P=0.01).At 1 year, 227/324 (70%) and 119/169 (70%) of the patients who did and did not have pre-procedural imaging were free from AF (P = NS). Figure 1 Conclusions Pre-procedural CT does not improve safety and efficacy of AF ablation, increasing significantly the cumulative radiological exposure. Considering that patients candidate to AF ablation are often young, the cumulative radiation dose per life span and radiation dose reduction strategies should remain a matter of concern for doctors. Acknowledgement/Funding None

Radiographic Accuracy of Percutaneous Pedicle Screw Placement in Fluoroscopic- Versus CT Navigation-Guided Lumbar Spine Instrumentation

Abstract INTRODUCTION Posterior spinal instrumentation for fusion using intraoperative computed tomography (CT) navigation is gaining traction as an alternative to the conventional two-dimensional fluoroscopic-guided approach to percutaneous pedicle screw placement. However, few studies to date have directly compared outcomes of these 2 minimally invasive instrumentation methods. METHODS A consecutive cohort of patients undergoing primary percutaneous posterior lumbar spine instrumentation for spine fusion was retrospectively reviewed. Revision surgeries or cases converted to open were excluded. Accuracy of screw placement was assessed using a postoperative CT scan with blinding to the surgical methods used. The Gertzbein-Robbins classification was used to grade cortical breach: Grade 0 (&lt;0 mm cortical breach), Grade I (&lt;2 mm), Grade II (2-4 mm), Grade III (4-6 mm), and Grade IV (&gt;6 mm). RESULTS CT navigation was found to significantly improve accuracy of screw placement (P &lt; .022). There was significantly more facet violation of the unfused level in the fluoroscopy group vs the CT group (9% vs 0.5%; P &lt; .0001). There was also a higher proportion of poor screw placement in the fluoroscopy group (10.1% vs 3.6%). No statistical difference was found in the rate of tip breach, inferomedial breach, or lateral breach. Regression analysis showed that fluoroscopy had twice the odds of incurring poor screw placement as compared to CT navigation. CONCLUSION This radiographic study comparing screw placement in minimally invasive fluoroscopy- vs CT navigation-guided lumbar spine instrumentation provides evidence that CT navigation significantly improves accuracy of screw placement, especially in optimizing the screw trajectory so as to avoid facet violation. Long-term follow-up studies should be performed to ascertain whether this difference can contribute to an improvement in clinical outcomes.

Use of Hisense Computer-Assisted Surgery System Enhances Infrapyloric Lymph Node Dissection for Gastric Cancer

BackgroundThis study aimed to establish a three-dimensional model of infrapyloric vessels using the Hisense computer-assisted surgery (CAS) system before the operation to understand blood vessel variation types and determine the group 6 lymph node (LN) metastasis status. MethodsOne hundred and four gastric cancer patients were randomly assigned to a CAS group and a computed tomography (CT) group. Intraoperative and postoperative complications in the two groups were recorded. The number of group 6 LNs dissected and the metastasis status were compared between the groups. The independent risk factors influencing group 6 LN metastasis were determined by multiple logistic regression analysis. ResultsIn the 50 CAS group patients, the gastrocolic trunk of Henle was divided into a gastrocolic type (34.0%) and a gastropancreatic colonic type (66.0%); the right gastroepiploic artery was divided into a coarse blood supply type (24.0%) and a fine blood supply type (76.0%); and the relationship between the right gastroepiploic artery and right gastroepiploic vein was divided into an adjacent type (58.0%) and a separated type (42.0%). Although the difference was not significant, the CAS group had fewer cases of intraoperative gastrocolic trunk injury and postoperative pancreatic leakage in trend than the CT group. The CAS group had more dissected LNs (P < 0.001) and metastatic LNs (P = 0.011) than the CT group; meanwhile, it had higher LN metastasis rate and LN metastasis degree in trend than the CT group. According to the multiple logistic regression model, tumor location and TNM stage were significantly correlated with group 6 LN metastases. ConclusionsBy establishing a three-dimensional model of the infrapyloric vessels using the Hisense CAS system, we comprehensively determined the anatomic variations in each collateral vessel. The application of the Hisense CAS system significantly improved the number of LNs dissected and the discovery rate of LN metastases without increasing the incidence of complications.

Changes of visualised Eustachian tube lengths by age and position: Radiologic study in sitting and supine positions using cone beam and conventional CT

Patulous eustachian tube (ET) has been characterised by the visualisation of full-length ET on computed tomography (CT) results. We wanted to investigate the changes of visualised ET lengths by age in supine and sitting positions. Retrospective study. Tertiary care academic referral centre. One hundred subjects who underwent cone beam CT (CBCT) in a sitting position and conventional CT in a supine position for non-otitis-related or dental complaints. Visualised ET lengths from the nasopharyngeal orifice measured by different positions and ages. Subjects did not show visualisation of full-length ET throughout the study. The visualised ET lengths (9.0±2.5mm) of the CBCT group were significantly larger than those (6.8±2.3mm) of the conventional CT group (P<0.0001).Women showed longer visualised ET lengths than men in CBCT group (P<0.001). The visualised ET lengths of the CBCT group were consistent or slightly increasing as a function of age (P=0.06); however, the visualised ET lengths of the conventional CT group decreased as a function of age (P=0.001). The slopes of regression lines of the two groups were significantly different. When in the supine position, the ET lengths gradually shortened as the subjects got older, most likely due to venous engorgement and the collapse of surrounding tissues; this finding thus suggests that CT in a supine position is an inappropriate method to diagnose patulous ET. The visualised ET lengths by CBCT in a sitting position were consistent throughout the different ages of the subjects and may be used as a diagnostic test for patulous ET.

Ultralow dose computed tomography protocol for hook-wire localization of solitary pulmonary nodules prior to video-assisted thoracoscopic surgery.

BackgroundThis study prospectively investigated the efficacy and radiation dose of ultralow dose computed tomography (CT)‐guided hook‐wire localization (HWL) at 100 kV with tin filtration (100Sn kV) for small solitary pulmonary nodules.MethodsAll HWL procedures were performed on a third generation dual‐source CT system. Eighty‐eight consecutive patients undergoing CT‐guided HWL were randomly assigned to standard dose CT (Group A: n = 44; reference 110 kV and 50 mA) or ultralow dose CT (Group B: n =44; 100Sn kV and 96 mA) protocols. The technical success rate, complications, subjective image quality, and radiation dose were compared between the groups.ResultsThe mean volume CT dose index and total dose‐length product were significantly lower in Group B compared to Group A (0.32 mGy vs. 3.2 ± 1.1 mGy and 12.1 ± 0.97 mGy‐cm vs. 120 ± 40.6 mGy‐cm; P < 0.001). The effective dose in Group B was significantly lower than in Group A (0.17 ± 0.01 mSv vs. 1.68 ± 0.57 mSv, ‐89.8%; P < 0.001). The technical success rates were 100% for both groups. There were no significant differences in complication rates between the protocols (P > 0.05). The image quality of ultralow dose CT met the requirements for HWL procedure.ConclusionUltralow dose CT‐guided HWL of solitary pulmonary nodules performed at 100Sn kVp spectral shaping significantly reduced the radiation dose compared to standard dose CT, with high technical success and acceptable patient safety.

Evaluation of common inspection techniques for acute atlantoaxial trauma

Objective To evaluate and compare the 3 common inspection techniques for acute atlantoaxial trauma: tomosynthesis (DTS), digital radiology (DR) and computed tomography (CT). Methods The imaging data from March 2013 through December 2017 were retrieved from the Picture Archiving and Communication Systems (PACS) of The First Affiliated Hospital of Chongqing Medical University concerning the patients with acute atlantoaxial trauma.Selected for this study were 50 DTS images (DTS group), 50 CT images (CT group) and 50 DR images (DR group).The image diagnoses for the 3 groups were conducted by 2 senior radiologists and their judgments were compared with the definite clinical diagnoses.The 3 groups were compared in terms of diagnostic accuracy, diagnostic rate of acute atlantoaxial trauma, image quality and effective radiation dosage. Results DR was insignificantly different from DTS or CT in diagnostic accuracy for the acute atlantoaxial trauma which had been caused by mild violence like spraining and falling (P>0.05), but significantly inferior to both DTS and CT in diagnostic accuracy and diagnostic rate of the acute atlantoaxial trauma which had been caused by severe violence like traffic accident (P<0.05).In detection of atlas/axial fracture and atlantoaxial dislocation, DTS was slightly weaker than CT but significantly better than DR (P< 0.05).The image quality scores for CT group (4.60±0.11) and DTS group (4.16±0.15) were significantly higher than that for DR group (2.80±0.18) (P<0.05).In average effective radiation dosage, CT group (2.33±0.020 mSv/time) was the highest, followed by DTS group (0.61±0.076 mSv/time) and DR group (0.025±0.003 mSv/time), showing significant differences between any two (P<0.05). Conclusions DR technique may be used for inspection of the atlantoaxial acute trauma caused by mild violence like spraining and falling, but has little value for inspection of most cases of atlantoaxial acute trauma.DTS technique may be the first choice for inspection of most atlantoaxial acute trauma.CT should be applied as a further inspection for complex cases because of its highest diagnostic accuracy and highest effective radiation dosage. Key words: Atlas; Axis; Tomography, spiral computed; Tomosynthesis; Digital radiology

Low-Dose Computed Tomography Reduces Radiation Exposure by 90% Compared With Traditional Computed Tomography Among Patients Undergoing Hip-Preservation Surgery

To compare the delivered radiation dose between a low-dose hip computed tomography (CT) scan protocol and traditional hip CT scan protocols (i.e., "traditional CT"). This was a retrospective comparative cohort study. Patients who underwent hip-preservation surgery (including arthroscopy, surgical hip dislocation, or periacetabular osteotomy procedures) at our institution between 2016 and 2017 were identified. Patients were excluded if they had a body mass index (BMI) greater than 35, they underwent previous surgery, or a radiation dose report was absent. The low-dose group included patients who underwent hip CT at our institution using a standardized protocol of 100kV (peak), 100 milliampere-seconds (mAs), and a limited scanning field. The traditional CT group included patients who had hip CT scans performed at outside institutions. The total effective dose (Ehip), effective dose per millimeter of body length scanned, patients' age, and patients' BMI were compared by univariate analysis. The correlation of Ehip to BMI was assessed. The study included 41 consecutive patients in the low-dose group and 18 consecutive patients in the traditional CT group. Low-dose CT resulted in a 90% reduction in radiation exposure compared with traditional CT (Ehip, 0.97 ± 0.28mSv vs 9.68 ± 6.67mSv; P < .0001). Age (28 ± 11years vs 26 ± 10years, P= .42), sex (83% female patients vs 76% female patients, P= .74), and BMI (24 ± 3 vs 24 ± 3, P= .75) were not different between the 2 groups. Ehip had a poor but significant correlation to BMI in the low-dose CT group (R2= 0.14, slope= 0.03, P= .02) and did not correlate to BMI in the traditional CT group (R2= 0.13, P= .14). A low-dose hip CT protocol for the purpose of hip-preservation surgical planning resulted in a 90% reduction in radiation exposure compared with traditional CT. Level II, diagnostic study.

Electromagnetic Navigation Bronchoscopy Localization Versus Percutaneous CT-Guided Localization for Lung Resection via Video-Assisted Thoracoscopic Surgery: A Propensity-Matched Study.

Background: An ideal preoperative localization method is essential for the resection of small and deep-seated pulmonary nodules by video-assisted thoracoscopic surgery (VATS) in the era of low-dose computed tomography (CT) screening. This study describes a new localization method using electromagnetic navigation bronchoscopy (ENB) and compares it against conventional percutaneous CT-guided methods. Methods: Between January 2016 and May 2018, 18 consecutive patients with a total of 27 pulmonary nodules underwent ENB localization using patent blue vital dye before thoracoscopy for lung resection at the National Taiwan University Hospital. Over the same period, 268 patients had a total of 325 pulmonary nodules localized by a CT-guided method. Propensity analysis was applied to minimize bias during comparison. Results: Patients were selected using a propensity-score based process, matched for potential risk factors for localization failure, to ensure equal potential prognostic factors in both groups. After matching, the ENB group had 15 patients with a total of 24 pulmonary nodules, and the CT group had 30 patients with 48 pulmonary nodules. No major procedure-related complications occurred in either group. The target pulmonary nodule was not successfully localized for one patient in the ENB group and three in the CT group. The lesions were fully excised after conversion to mini-thoracotomy. Pathological examination confirmed the accuracy of the dye staining. Analysis found a non-significant difference in the success rate of these two localization methods. However, the following parameters were significantly different: interval between localization to surgery, global time, and rate of pneumothorax (p < 0.05). Conclusions: In the era of minimally invasive surgery, surgeons need an efficient one-step way to manage pulmonary nodules. Patent blue vital injection with ENB guidance in the operating room is a new, effective approach to localize small, deep-seated and non-palpable pulmonary lesions, comparable with CT-guided localization.