Standard Computed Tomography Scans Research Articles

Deep learning for head and neck semi-supervised semantic segmentation

Objective. Radiation therapy (RT) represents a prevalent therapeutic modality for head and neck (H&N) cancer. A crucial phase in RT planning involves the precise delineation of organs-at-risks (OARs), employing computed tomography (CT) scans. Nevertheless, the manual delineation of OARs is a labor-intensive process, necessitating individual scrutiny of each CT image slice, not to mention that a standard CT scan comprises hundreds of such slices. Furthermore, there is a significant domain shift between different institutions’ H&N data, which makes traditional semi-supervised learning strategies susceptible to confirmation bias. Therefore, effectively using unlabeled datasets to support annotated datasets for model training has become a critical issue for preventing domain shift and confirmation bias. Approach. In this work, we proposed an innovative cross-domain orthogon-based-perspective consistency (CD-OPC) strategy within a two-branch collaborative training framework, which compels the two sub-networks to acquire valuable features from unrelated perspectives. More specifically, a novel generative pretext task cross-domain prediction (CDP) was designed for learning inherent properties of CT images. Then this prior knowledge was utilized to promote the independent learning of distinct features by the two sub-networks from identical inputs, thereby enhancing the perceptual capabilities of the sub-networks through orthogon-based pseudo-labeling knowledge transfer. Main results. Our CD-OPC model was trained on H&N datasets from nine different institutions, and validated on the four local intuitions’ H&N datasets. Among all datasets CD-OPC achieved more advanced performance than other semi-supervised semantic segmentation algorithms. Significance. The CD-OPC method successfully mitigates domain shift and prevents network collapse. In addition, it enhances the network’s perceptual abilities, and generates more reliable predictions, thereby further addressing the confirmation bias issue.

Ethnic differences in CT derived abdominal body composition measures: a comparative retrospect pilot study between European and Inuit study population

ABSTRACT Understanding ethnic variations in body composition is crucial for assessing health risks. Universal models may not suit all ethnicities, and there is limited data on the Inuit population. This study aimed to compare body composition between Inuit and European adults using computed tomography (CT) scans and to investigate the influence of demographics on these measurements. A retrospective analysis was conducted on 50 adults (29 Inuit and 21 European) who underwent standard trauma CT scans. Measurements focused on skeletal muscle index (SMI), various fat indices, and densities at the third lumbar vertebra level, analyzed using the Wilcoxon-Mann-Whitney test and multiple linear regression. Inuit women showed larger fat tissue indices and lower muscle and fat densities than European women. Differences in men were less pronouncehd, with only Intramuscular fat density being lower among Inuit men. Regression indicated that SMI was higher among men, and skeletal muscle density decreased with Inuit ethnicity and age, while visceral fat index was positively associated with age. This study suggests ethnic differences in body composition measures particularly among women, and indicates the need for Inuit-specific body composition models. It higlights the importance of further research into Inuit-specific body composition measurements for better health risk assessment.

Utility of fluoro-deoxy-glucose positron emission tomography (FDG-PET) to predict a pelvic lymph node involvement (LNI) in patients (pts) with muscle-invasive bladder cancer (MIBC) enrolled in neoadjuvant therapy trials.

527 Background: FDG-PET is reported to have limited utility in pts with MIBC. However, standard computed tomography (CT) imaging can often underestimate disease extent, and its role in predicting a pathological pelvic lymph node involvement (LNI) is very limited. Previous findings from PURE-01 trial reported a potential use of FDG-PET to exclude the few pts with T2-4N0M0 and pelvic LN uptake from neoadjuvant trials with immune-checkpoint inhibitors (ICI; PMID: 33071107). The aim of this study was to extend these findings to a wider range of experimental therapies. Methods: We collected the data of pts with clinical stage T2-4N0-1M0 MIBC included in past and ongoing neoadjuvant trials sponsored by our center, including single agent or combination of immune-checkpoint inhibitors (ICI), ICI+chemotherapy (ChT), standard ChT and sacituzumab govitecan. All pts had predominant urothelial carcinoma (UC) histology and were staged with standard thorax-abdomen CT scan and with PET/CT scan during screening and after treatment, before radical cystectomy (RC). PET/CT images were evaluated qualitatively for increased or abnormal areas of FDG uptake with corresponding anatomic alterations in CT slices. All pts underwent templated pelvic lymph node dissection (LND) with packeted node submission. Multivariable logistic regression analyses (MVA) for pathological LNI prediction were run, including cT-stage and the presence of variant histologies (VH). Results: A total of 149 pts (298 PET scans) were identified, treated between 02/2017 and 08/2023. 112 pts (75.2%) received ICI, 26 (17.4%) ICI+ChT, 11 (7.4%) the remaining therapies. 36 pts (24%) had a VH, 72 (48%) a cT3-4 stage, and 12 (8.1%) a cN1 stage. In total, 20 (13%) and 16 (11%) pts had PET+ pre- and post-therapy, respectively. The accuracy of FDG-PET and CT scan in predicting LNI in overall pts was similar, both pre-therapy (85.3% and 86.7%) and post therapy (86.7%, 84.6%), the only exceptions being a lower accuracy of PET to predict presacral LNI (76.6%, 78.8% pre- and post-therapy) and in VH pre-therapy (84.3% vs 90.9% PET vs CT). A pre-therapy FDG uptake significantly predicted a pathological LNI in MVA (OR: 17.8, 95%CI: 4.18-94.86, p<0.001, AUC: 0.89), with consistent results in T2-4N0M0 cohort (OR: 18.17, 95%CI: 4.15-99.25, p<0.001, AUC: 0.84). Conclusions: Despite the proportion of FDG-PET positive pts was modest in T2-4N0-1M0 MIBC, we were able to confirm that these pts were predicted to be poor responders to neoadjuvant therapies regardless of the type of treatment. FDG-PET had lower prediction ability of LNI in presacral LN region and in pts with a VH. This information should be critically considered for patient selection in neoadjuvant therapy trials.

Histogram-Based Densitometry Index to Assess the Severity of Interstitial Lung Disease in Systemic Sclerosis in Standard and Low-Dose Computed Tomography.

Mean lung attenuation, skewness, and kurtosis are histogram-based densitometry variables that quantify systemic sclerosis-associated interstitial lung disease (SSc-ILD) and were recently merged into a computerized integrated index (CII). Our work tested the CII in low-dose 9-slice (reduced) and standard high-resolution computed tomography (CT) scans to evaluate extensive SSc-ILD and predict mortality. CT scans from patients with SSc-ILD were assessed using the software Horos to compute standard and reduced CIIs. Extensive ILD was determined following the Goh staging system. The association between CIIs and extensive ILD was analyzed with a generalized estimating equation regression model, the predictive ability of CIIs by the area under the receiver-operation characteristic curve (AUC), and the association between CIIs and death by Kaplan-Meier analysis. Among 243 patients with standard and reduced CT scans available, 157 CT scans from 119 patients with SSc-ILD constituted the derivation cohort. The validation cohort included 116 standard and 175 reduced CT scans. Both CIIs from standard (odds ratio [OR] 0.53, 95% CI 0.37-0.75; AUC 0.77, 95% CI 0.68-0.87) and reduced CT scans (OR 0.54, 95% CI 0.35-0.82; AUC 0.78, 95% CI 0.70-0.87) were significantly associated with extensive ILD. A threshold of CII ≤ -0.96 for standard CT scans and CII ≤ -1.85 for reduced CT scans detected extensive ILD with high sensitivity in both derivation and validation cohorts. Extensive ILD according to Goh staging (OR 2.94, 95% CI 1.10-7.82) and standard CII ≤ -0.96 (OR 1.78, 95% CI 1.24-2.56) significantly predicted mortality; a marginal P value was observed for reduced CII ≤ -1.85 (OR 1.27, 95% CI 0.93-1.75). Thresholds for both standard and reduced CII to identify extensive ILD were developed and validated, with an additional association with mortality. CIIs might help in clinical practice when radiology expertise is missing.

Straight Leg Raise Cannot Replace Computed Tomography in the Detection of Spinal Column Fractures

IntroductionAn active straight leg raise (SLR) is a weight bearing test which assesses pain upon movement and a patient's ability to load their pelvis, lumbar, and thoracic spine. Since many stable patients undergo computed tomography (CT) scanning solely for spinal tenderness, our hypothesis is that performing active straight leg raising could effectively rule out lumbar and thoracic vertebral fractures. MethodsBlunt trauma patients ≥18 years of age with Glasgow Coma Scale 15 presenting in hemodynamically stable condition were screened. Patients remaining in the supine position were asked to perform SLR at 12, 18, and 24 inches above the bed. The patient's ability to raise the leg, baseline pain, and pain at each level were assessed. Patients also underwent standard CT scanning of the chest, abdomen and pelvis. The clinical examination results were then matched post hoc with the official radiology reports. Results99 patients were screened, 65 males and 34 females. Spinal fractures were present in 15/99 patients (16%). Mechanisms of injury included motor vehicle collision 51%, pedestrian struck 25%, fall1 9%, and other 4%. The median pain score of patients with and without significant spinal fractures at 12, 18, 24 inches was 7.5, 7, 6 and 5, 5, 4, respectively. At 24 inches, active SLR had sensitivity of 0.47, a specificity of 0.59, a positive predictive value of 0.17, and an negative predictive value of 0.86. ConclusionsAlthough SLR has been discussed as a useful adjunct to secondary survey and physical exam following blunt trauma, its positive and more importantly negative predictive value are insufficient to rule out spinal column fractures. Liberal indications for CT based upon mechanism and especially pain and tenderness are necessary to identify all thoraco-lumbar spine fractures.

Influence of cellular models and individual factor in the biological response to head CT scan exams

BackgroundWhile computed tomography (CT) exams are the major cause of medical exposure to ionising radiation, the radiation-induced risks must be documented. We investigated the impact of the cellular models and individual factor on the deoxyribonucleic acid double-strand breaks (DSB) recognition and repair in human skin fibroblasts and brain astrocytes exposed to current head CT scan conditions.MethodNine human primary fibroblasts and four human astrocyte cell lines with different levels of radiosensitivity/susceptibility were exposed to a standard head CT scan exam using adapted phantoms. Cells were exposed to a single-helical (37.4 mGy) and double-helical (37.4 mGy + 5 min + 37.4 mGy) examination. DSB signalling and repair was assessed through anti-γH2AX and anti-pATM immunofluorescence.ResultsHead CT scan induced a significant number of γH2AX and pATM foci. The kinetics of both biomarkers were found strongly dependent on the individual factor. Particularly, in cells from radiosensitive/susceptible patients, DSB may be significantly less recognised and/or repaired, whatever the CT scan exposure conditions. Similar conclusions were reached with astrocytes.ConclusionsOur results highlight the importance of both individual and tissue factors in the recognition and repair of DSB after current head CT scan exams. Further investigations are needed to better define the radiosensitivity/susceptibility of individual humans.

Influence of cellular models and individual factor in the biological response to chest CT scan exams

BackgroundWhile computed tomography (CT) exams are the major cause of medical exposure to ionising radiation, there is increasing evidence that the potential radiation-induced risks must be documented. We investigated the impact of cellular models and individual factor on the deoxyribonucleic acid double-strand breaks (DSB) recognition and repair in human fibroblasts and mammary epithelial cells exposed to current chest CT scan conditions.MethodTwelve human primary fibroblasts and four primary human mammary epithelial cell lines with different levels of radiosensitivity/susceptibility were exposed to a standard chest CT scan exam using adapted phantoms. Cells were exposed to a single helical irradiation (14.4 mGy) or to a topogram followed, after 1 min, by one single helical examination (1.1 mGy + 14.4 mGy). DSB signalling and repair was assessed through anti-γH2AX and anti-pATM immunofluorescence.ResultsChest CT scan induced a significant number of γH2AX and pATM foci. The kinetics of both biomarkers were found strongly dependent on the individual factor. The topogram may also influence the biological response of radiosensitive/susceptible fibroblasts to irradiation. Altogether, our findings show that a chest CT scan exam may result in 2 to 3 times more unrepaired DSB in cells from radiosensitive/susceptible patients.ConclusionsBoth individual and tissue factors in the recognition and repair of DSB after current CT scan exams are important. Further investigations are needed to better define the radiosensitivity/susceptibility of individual humans.

Protocol for a pilot feasibility, safety and efficacy study of artificially introducing an air-pleura interface for detection of pleural nodules by computed tomography: the AIR study

Abstract Background: Pleural effusions are common and can arise from many causes including primary or metastatic malignancies. Computed tomography (CT) is part of the routine workup for pleural effusions especially if pleural fluid analysis fails to show an underlying cause. CT can help detect pleural abnormalities such as thickening or nodules and allow imaging guided percutaneous biopsies. Otherwise surgical procedures are often required to obtain histological specimens but have inherent risks. The presence of air in the pleural cavity (eg with trapped lung) has been shown in a case series to enhance CT detection of pleural abnormalities. The AIR study is a prospective, pilot, proof-of-concept study to assess the feasibility and safety of instilling air intrapleurally to create an air-pleura interface during CT imaging, and the efficacy of this artificial pneumothorax in aiding CT detection of pleural abnormalities. Methods: This study will recruit 40 patients with suspected or proven malignant pleural effusions that have a chest tube (including indwelling pleural catheter) in-situ and no pre-existing radiological evidence of advanced pleural abnormalities. A standard CT scan with pleural phase contrast enhancement will be performed. Air will be instilled via the chest tube to introduce an artificial air-pleura interface and a second (non-contrast) CT chest scan will be performed in the prone position. The air will be immediately aspirated after the procedure. The aims of this study are to determine 1) the feasibility and safety of introducing an air-pleura interface using a pre-defined protocol and 2) its effectiveness in detecting additional pleural abnormalities. Discussion: The AIR study is the first study to evaluate the feasibility, safety and efficacy of creating an artificial air-pleura interface to enhance detection of pleural abnormalities by CT. Improvements in detection may inform imaging-guided tissue sampling, avoid more invasive tissue acquisition procedures, and add to the assessment of pleural disease burden.

270. Low Hounsfield Units measured at the upper instrumented vertebra are an independent risk factor for density related complications in adult spinal fusion procedures

<h3>BACKGROUND CONTEXT</h3> Hounsfield unit values (HU) from computed tomography (CT) have been used to informally assess bone density in patients undergoing spine fusion procedures. HUs are easily obtained from a standard preoperative CT scan, and unlike Dual X-ray Absorptiometry analysis (DEXA) one can focus on specific regions of interest, such as the vertebral body of a planned upper-instrumented vertebrae (UIV). There is still a relative lack of literature on the reliability and utility of HUs to both identify patients with low BMD and guide surgical decision making. <h3>PURPOSE</h3> To determine whether there was a significant difference in preoperative HUs, measured at the UIV, in patients that had a bone-density related complication (DRC) within 2 years of their spinal fusion. <h3>STUDY DESIGN/SETTING</h3> A retrospective comparative study at a single academic institution. <h3>PATIENT SAMPLE</h3> Patients 55 years or older that underwent a spinal fusion procedure in 2017 at a single academic institution. <h3>OUTCOME MEASURES</h3> Occurrence of proximal junctional kyphosis, proximal junctional failure, pseudarthrosis, screw loosening or pullout, hardware failure and adjacent segment disease (ASD). <h3>METHODS</h3> Baseline preoperative demographic information, smoking history, levels fused, UIV and status as a revision procedure were recorded. All postoperative notes and images for 2 years post-procedure were reviewed for the presence of proximal junctional kyphosis, proximal junctional failure, pseudarthrosis, screw loosening or pullout, hardware failure, and ASD. HUs were measured via regions of interest drawn within the cancellous bone of the mid-vertebral body at the UIV of all patients. Patients were divided into 2 groups for comparison, those who experienced a DRC within 2 years and those who did not. Student's t-test was performed to compare HUs between the groups, chi-square analysis was performed for categorical variables. Dichotomous logistical regression was performed to analyze the relationship between density related complications and HU at the UIV, patient BMI, revision procedure, history of smoking, gender, UIV and number of levels fused. Significance was set at p<0.05. <h3>RESULTS</h3> A total of 172 consecutive fusion patients with a preoperative CT scan were reviewed. Of these, 49 were revision procedures. 66 had a UIV in the cervical spine, 10 had a UIV in the thoracic spine and 95 had a UIV in the lumbar spine. Ninety-nine were 1 or 2 level fusions, 49 were 3 or 4 level fusions and 23 were long fusions with 4+ levels involved. Forty-eight patients had a DRC. Baseline demographics were similar between the 2 groups, with the exception of more revision procedures in the DRC group (p<0.001). The mean HUs of the UIV in the cohort that had a DRC was 168.92, as compared to 252.66 in the no-DRC group (p<0.001). Regression analysis revealed that low HUs at the UIV and revision procedures were independent risk factors for a DRC. For every 10 unit decrease in HUs, the odds of a DRC rose by 6%. When thoracic and lumbar fusions were analyzed the mean HUs at the UIV in the DRC group were 108.5 vs 152.6 (p<0.001). When cervical fusions were analyzed separately the mean HUs in the DRC group were 308 vs 383.4 (P=0.014). <h3>CONCLUSIONS</h3> To our knowledge, this is the first study that compares HUs measured at the UIV to the rate of density related complications for single and multilevel fusions in the cervical, thoracic and lumbar spine. This study found that HUs measured at the UIV of a fusion were significantly lower in patients that went on to have a density related complication within 2 years of their index procedure. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Determining C2 Pedicle Screw Placement Feasibility in the Pediatric Population: A Computed Tomographic Safe Zone Analysis.

Due to high rates of anatomic variability of the C2 pedicle, thin-sliced pedicular-oriented computed tomography (CT) and 3-dimensional reconstructive CT technologies have been introduced to predict safe C2 pedicle screw placement. However, this technology may not be readily available in all centers. The purpose of this study was to perform a C2 pedicle safe zone analysis using standard sagittal CT scans to predict the feasibility of C2 pedicle screw placement in a pediatric population and to compare the results with our previously obtained safe zone analysis from the adult population. A retrospective analysis was performed at a single level I trauma center of pediatric patients who completed CT scans of the cervical spine. The feasibility of C2 pedicle screw placement was analyzed using our previously described C2 pedicle safe zone analysis technique. The risk profiles were compared with our previously obtained safe zone analysis from the adult population. Thirty-nine consecutive patients with a mean age of 7.8±4.4 years and 78 total pedicles were included in the study. Fourteen pedicles (18%) were considered low risk, 37 (47%) were moderate risk, and 27 (35%) were high risk for vertebral artery injury. Individual patients were found to have a significant amount of side-to-side variability between pedicles with 21 patients (54%) having left and right pedicles with different risk profiles. Four patients (10%) demonstrated low risk profiles in bilateral pedicles. There was no significant difference between the risk profiles of pediatric and adult patients. There is a considerable amount of anatomic variability within the pediatric C2 pedicles. Using this simple and accessible technique during the review of preoperative imaging, C2 pedicle screw placement may be considered in appropriately selected pediatric patients. Level III.

The effect of native knee rotation on the tibial-tubercle-trochlear-groove distance in patients with patellar instability: an analysis of MRI and CT measurements.

This study aimed to quantify the effect of lower limb rotational parameters on the difference in the tibial-tubercle-trochlear-groove (TTTG) distance when assessed with magnetic resonance imaging (MRI) and computed tomography (CT) in patients with patellar instability. It was hypothesized that an increased native knee rotation angle significantly contributes to an underestimation of TTTG by MRI. Forty patients with patellar instability who had undergone standard radiographs, MRI and CT scans were included in this retrospective study. A musculoskeletal radiologist assessed all imaging for TTTG, femoral and tibial rotation, knee rotation and flexion angle, and trochlear dysplasia. ΔTTTG was defined as the TTTG measured on MRI subtracted from the TTTG measured on CT. Statistical analysis determined the effect of these parameters on the calculated difference between TTTG when measured on CT and MRI. Equal knee flexion in MRI and CT resulted in a ΔTTTG of 0.1 ± 0.3mm compared to 4.0 ± 3.3mm in patients with different knee flexion angles in both imaging acquisitions (p = 0.036). The knee rotation angle measured on CT (native knee rotation angle) was negatively correlated with ΔTTTG (r = - 0.365; p = 0.002), while neither tibial nor femoral rotation showed any associations with TTTG (n.s.). Trochlear dysplasia did not show any significant correlation with ΔTTTG, regardless of classification by Dejour or Lippacher (n.s.). Both the native knee rotation angle and the MRI knee flexion angle were independent predictors of ΔTTTG, yet with an opposing effect (knee rotation: 95% Confidence Interval [CI] for β - 0.468 to - 0.154, p < 0.001; knee flexion 95% CI for β 0.292 to 0.587, p < 0.001). Patients with a native knee rotation angle > 20° showed a ΔTTTG of - 5.8 ± 4.0mm (MRI rather overestimates TTTG) compared to 0.9 ± 4.1mm Δ TTTG (MRI rather underestimates TTTG) in patients with < 20° native knee rotation angle. The native knee rotation angle is an independent, inversely correlated predictor of ΔTTTG, thus opposing the effect of knee flexion during MRI acquisition. Consequently, these results suggest that not only knee flexion but also knee rotation should be appreciated when assessing TTTG during patellar instability diagnostic evaluation as it can potentially lead to a false estimation of the TTTG distance on MRI. Level III.

There is motion between the scaphoid and the lunate during the dart-throwing motion

Scaphoid and lunate mobility has been suggested to be minimal during the dart-throwing motion in studies based on serial computed tomography (CT) scans and cadaver studies. This study analyzes the direct motion between the scaphoid and the lunate during the dart-throwing motion in vivo. We examined nine individuals with standard CT scans of the wrist in radial extension and ulnar flexion. The paired CT scans were analyzed with a volume registration technique. The lunate was registered as fixed and the scaphoid as the mobile element. The motion of the scaphoid relative the lunate between the positions of radial extension and ulnar flexion was measured. There was considerable motion between the scaphoid and the lunate with both a distal to proximal translation and rotation during the dart-throwing motion, regardless of whether the scapholunate ligament was intact or not. These results suggest that aggressive dart-throwing exercises should not be implemented early on during rehabilitation following scapholunate repair.

Incremental Diagnostic Value of Virtual Noncalcium Dual-Energy Computed Tomography for the Depiction of Cervical Disk Herniation Compared With Standard Gray-Scale Computed Tomography.

The aim of this study was to investigative the diagnostic accuracy of colored dual-energy computed tomography (CT) virtual noncalcium (VNCa) series for analyzing cervical disk herniation compared with standard gray-scale CT images, with magnetic resonance imaging (MRI) serving as standard of reference. Data from 57 patients who underwent noncontrast dual-source CT and 3.0-Tesla (T) MRI within 2 weeks between January 2017 and December 2018 were retrospectively analyzed. Five radiologists analyzed standard gray-scale dual-energy CT scans for the presence and degree of cervical disk herniation and spinal nerve root impingement. Readers reassessed scans after 8 weeks using colored VNCa series. Two experienced radiologists set the reference standard in consensus MRI reading sessions. Primary indices of diagnostic accuracy for both CT approaches were sensitivity and specificity, which were compared by application of the McNemar test. A total of 57 patients (mean age, 64 ± 11 years; 30 women) were evaluated (337 intervertebral disks). Magnetic resonance imaging indicated a total of 103 cervical disk herniations. The VNCa reconstructions had higher overall sensitivity compared with gray-scale CT (487/515 [95%; 95% confidence interval (CI), 91%-98%] vs 392/515 [76%; 95% CI, 70%-83%]), as well as higher specificity (1107/1170 [95%; 95% CI, 90%-99%] vs 906/1170 [77%; 95% CI, 72%-82%]) for assessing cervical disk herniation (all P < 0.001). The VNCa reconstructions had higher diagnostic accuracy for analyzing spinal nerve root impingement in comparison with gray-scale CT (sensitivity, 195/230 [85%; 95% CI, 79%-90%] vs 115/230 [50%; 95% CI, 40%-59%]; specificity, 1430/1455 [98%; 95% CI, 94%-100%] vs 1325/1455 [91%; 95% CI, 88%-98%]; accuracy, 1625/1685 [96%; 95% CI, 93%-99%] vs 1440/1685 [86%; 95% CI, 82%-90%]; all P < 0.001). Color-coded VNCa series improved the diagnostic accuracy for assessing cervical disk herniation and spinal nerve root impingement compared with standard gray-scale CT.

Humeral head subluxation in Walch type B shoulders varies across imaging modalities.

BackgroundThe Walch type B pattern of glenohumeral osteoarthritis is characterized by posterior humeral head subluxation (PHHS). At present, it is unknown whether the percentage of subluxation measured on axillary radiographs is consistent with measurements on 2-dimensional (2D) axial or 3-dimensional (3D) volumetric computed tomography (CT). The purpose of this study was to evaluate PHHS across imaging modalities (radiographs, 2D CT, and 3D CT).MethodsA cohort of 30 patients with Walch type B shoulders underwent radiography and standardized CT scans. The cohort comprised 10 type B1, 10 type B2, and 10 type B3 glenoids. PHHS was measured using the scapulohumeral subluxation method on axillary radiographs and 2D CT. On 3D CT, PHHS was measured volumetrically. PHHS was statistically compared between imaging modalities, with P ≤ .05 considered significant.ResultsThe mean PHHS value for the entire group was 69% ± 24% on radiographs, 65% ± 23% with 2D CT, and 74% ± 24% with 3D volumetric CT. PHHS as measured on complete axillary radiographs was not significantly different than that measured on 2D CT (P = .941). Additionally, PHHS on 3D volumetric CT was 9.5% greater than that on 2D CT (P < .001). There were no significant differences in PHHS between the type B1, B2, and B3 groups with 2D or 3D CT measurement techniques (P > .102).ConclusionSignificant differences in PHHS were found between measurement techniques (P < .035). A 9.5% difference in PHHS between 2D and 3D CT can be mostly accounted for by the linear (2D) vs. volumetric (3D) measurement techniques (a linear 80% PHHS value is mathematically equivalent to a volumetric PHHS value of 89.6%). Surgeons should be aware that subluxation values and therefore thresholds vary across different imaging modalities and measurement techniques.

Advanced CT visualization improves the accuracy of orthopaedic trauma surgeons and residents in classifying proximal humeral fractures: a feasibility study.

Osteosynthesis of proximal humeral fractures remains challenging with high reported failure rates. Understanding the fracture type is mandatory in surgical treatment to achieve an optimal anatomical reduction. Therefore, a better classification ability resulting in improved understanding of the fracture pattern is important for preoperative planning. The purpose was to investigate the feasibility and added value of advanced visualization of segmented 3D computed tomography (CT) images in fracture classification. Seventeen patients treated with either plate-screw-osteosynthesis or shoulder hemi-prosthesis between 2015 and 2019 were included. All preoperative CT scans were segmented to indicate every fracture fragment in a different color. Classification ability was tested in 21 orthopaedic residents and 12 shoulder surgeons. Both groups were asked to classify fractures using three different modalities (standard CT scan, 3D reconstruction model, and 3D segmented model) into three different classification systems (Neer, AO/OTA and LEGO). All participants were able to classify the fractures more accurately into all three classification systems after evaluating the segmented three-dimensional (3D) models compared to both 2D slice-wise evaluation and 3D reconstruction model. This finding was significant (p < 0.005) with an average success rate of 94%. The participants experienced significantly more difficulties classifying fractures according to the LEGO system than the other two classifications. Segmentation of CT scans added value to the proximal humeral fracture classification, since orthopaedic surgeons were able to classify fractures significantly better into the AO/OTA, Neer, and LEGO classification systems compared to both standard 2D slice-wise evaluation and 3D reconstruction model.

Opportunistic muscle measurements on staging chest CT for extremity and truncal soft tissue sarcoma are associated with survival.

Computed tomography (CT) measurements of sarcopenia have been proposed as biomarkers associated with outcomes in various cancers and have typically been evaluated at the L3 vertebral level. However, staging imaging for patients with extremity and truncal soft tissue sarcoma (STS) often only includes chest CT imaging which precludes evaluation at L3. Therefore, we sought to evaluate muscle metrics at T12 on standard staging chest CT scans and evaluate for correlation with overall and event-free survival in patients with STS. CT chest imaging for 89 patients with intermediate and high-grade STS (53 male, 36 female; 58.5 ± 19.0 years old, follow-up 37.4 ± 27.1 months) was reviewed on PACS at T12 for skeletal muscle density (SMD) and skeletal muscle index (SMI). Overall survival increased with increased SMD on univariate (hazard ratio [HR] = 0.61 [0.43, 0.86]) and age-adjusted analysis (HR = 0.65 [0.42, 0.89]. Event-free survival also increased with increased SMD in univariate analyses (HR = 0.68 [0.49, 0.95]) but did not maintain significance after adjusting for age (HR = 0.68 [0.43, 1.07]). SMI was not a predictor of overall or event-free survival. Higher SMD measured on routinely obtained staging chest CTs in STS patients is associated with improved survival.

The Value of Low-dose Prospective Dual-energy Computed Tomography with Iodine Mapping in the Diagnosis of Gastric Cancer.

This study investigated the radiation dose and value of prospective dualenergy computed tomography (DECT) in the diagnosis of gastric cancer. Sixty patients scheduled for computed tomography (CT) for preoperative staging were divided into two groups. Thirty patients (Group A) underwent a single contrast-enhanced abdominal CT acquisition using a dual-source mode (100 kV/140 kV). Weighted average images of the two-kilovolt acquisitions and iodine maps were created. The remaining 30 patients underwent a standard CT scan (Group B). Two observers performed a blinded read of the images for gastric lesions, evaluating the image quality and recording effective dose. During the blinded read, observers found 90% (27/30) of the cancers in both groups. The mean imaging quality scores were 2.1±0.9 for Group A, and 2.3±1.1 for Group B. The effective mean doses were 6.59±0.59 mSv and 25.86±0.44 mSv for Groups A and B, respectively. Compared with the control group (B), the imaging quality in the low-dose group decreased a little, but the radiation dose substantially decreased by 74.6%. The new DECT technique is valuable for examining gastric cancer patients. The dualkV scan mode can substantially reduce radiation dose while preserving good diagnostic image quality.

Diagnostic accuracy of CT scan-based criteria compared with surgical exploration for the analysis of cervical fusion and nonunion.

Computed tomography (CT) scans are accepted as the imaging standard of reference to define union after anterior cervical discectomy and fusion (ACDF). However, ideal CT criteria to diagnose union have not been identified or validated. The objective of this study was to analyze the diagnostic value of 9 CT-based criteria and identify the ideal criteria among them to assess cervical fusion after ACDF using surgical exploration as the standard of reference. The authors performed a retrospective radiographic study of a single surgeon's prospective assessment of osseous fusion during cervical revision surgery by analyzing complete radiographic data in 44 patients who underwent anterior cervical revision surgery due to symptomatic suspected nonunion or adjacent level disease. All patients received standard preoperative CT scans, which were assessed by an independent radiologist to evaluate 9 diagnostic criteria for osseous union. During revision surgery, scar tissue was removed and manual segmental translation tests were performed. Nonunion was defined by visualized motion at the treated ACDF level. In total, 44 patients were included in the study (30 men; patient age 54 ± 6 years, BMI 28 ± 5 kg/m2). For analysis of fusion, 75 cervical levels were explored, of which 61 levels (81%) showed intraoperative movement indicating nonunion. Statistical analysis showed that of the 9 parameters used to diagnose bone union, "bridging bone on ≥ 3 CT slices" yielded the highest sensitivity (100%) and specificity (58%). Multivariate analysis revealed that prediction accuracy was not increased if several criteria were combined to determine fusion. The authors found that the best indicator of bone union was the item bridging bone on ≥ 3 CT slices. Combining the scoring of more than one criterion did not increase the diagnostic accuracy.

Impact of 18FDG-PET CT in the management of invasive bladder cancer.

444 Background: Guidelines do not recommend FDG-Positron Emission Tomography (PET) Computed Tomography (CT) for the staging of Muscle Invasive Bladder Cancer (MIBC), but rather CT scan for lymph node (LN) and metastatic staging, despite its low accuracy. We performed a retrospective analysis of patients (pts) with MIBC who had a FDG-PET CT for staging, indicated by multidisciplinary team, in two centers, and analyzed its utility in this setting. Methods: All pts who had a FDG-PET CT performed at the time of diagnosis of MIBC from 01/2005 to 12/2017 in Bordeaux (Bergonie Institute and University Hospital) were retrospectively reviewed. Nodal and metastatic staging on CT and FDG-PET CT were done independently according to the 8th TNM classification. The aims of the study were to evaluate the accuracy of the FDG-PET CT for LN staging and to determine the rate of treatment modification (neoadjuvant chemotherapy for curative intent, no surgery for metastatic disease), according to FDG-PET CT results. Results: Among the 130 pts included, with a median age of 65 years, 74% were considered free from nodal metastasis (N0) by CT whereas only 44% were N0 from FDG-PET CT. Based on CT results, 88% of pts were free from distant metastasis (M0) but only 75% were classified M0, on FDG-PET CT. Accuracy of LN staging for CT and FDG-PET CT at initial diagnosis were analyzed for 85 pts (including 70 pts treated with neoadjuvant chemotherapy) and compared to pathological examination of resected LN. Sensitivity of FDG-PET CT was better than CT (respectively 80.8% versus 26.9%) but the specificity was low (respectively 54.2% versus 83.1%). Youden index was better for FDG-PET CT (0.35; 0.1 for CT), being more accurate for determining LN staging of MIBC. FDG-PET CT findings allowed a treatment decision modification in 34/130 pts (26.1%): therapeutic intensification in 12 pts (9.2%), including surgery not previously indicated, modified radiotherapy; or de-escalation in 22 pts (16.9%), mostly avoiding surgery. Conclusions: FDG-PET CT is more sensitive to detect LN involvement at initial diagnosis of MIBC than standard CT scan. Moreover, in the present study, treatment decisions were modified, according to FDG-PET CT results, in a quarter of pts according to LN and distant metastatic staging.

Normal Anatomical Variants of the Paranasal Sinuses at Computed Tomography Scanning

Background: Recognition of PNS (Paranasal sinus) anatomic variants is particularly important in preoperative workup of patients with sinonasal pathology. CT (computed tomography) scanning can give exquisite details on sinus anatomy and pathology and is the main modality used to image the paranasal sinuses so the aim of the study isto evaluate certain anatomic variants of the paranasal sinuses in patients referred to the CT unit in Al-Immamain Al-Kadhymain Medical City. Patients and Method: We retrospectively analyzed the CT scans of the paranasal sinuses for patients referred to the CT unit in Al-Immamain Al-Kadhymain Medical City/Baghdad, Iraq for a period of 12 months . All the patients included in the study underwent standard CT scan of the PNS. Results: A net sample size of 188 was analyzed by the current study. Female: Male ration was (1.26:1).The incidence of septal deviation in the study sample was (51.06%) slightly more cases were deviated to the right (51.4%) than to the left (48.95%).Paradoxical middle turbinate’s were observed in(18.6%), middle turbinate aeration was observed in (58.5%) on the right and (53.1%) on the left. The incidence of variant air cells were as follows: Onodi (24.4%), Haller (11.1%), and Aggernasi (87.7%). Conclusion:The percent of most of the anatomical variants in our study sample was approximate to the percent published in the literature with the most common anatomic variants encountered being septal deviation followed by aerated middle turbinate’s whether unilateral or bilateral. The most frequent air cell was Aggernasi present in 87.7%.