Axial Computed Tomography Images Research Articles

End-to-end domain knowledge-assisted automatic diagnosis of idiopathic pulmonary fibrosis (IPF) using computed tomography (CT).

Domain knowledge (DK) acquired from prior studies is important for medical diagnosis. This paper leverages the population-level DK using an optimality design criterion to train a deep learning model in an end-to-end manner. In this study, the problem of interest is at the patient level to diagnose a subject with idiopathic pulmonary fibrosis (IPF) among subjects with interstitial lung disease (ILD) using a computed tomography (CT). IPF diagnosis is a complicated process with multidisciplinary discussion with experts and is subject to interobserver variability, even for experienced radiologists. To this end, we propose a new statistical method to construct a time/memory-efficient IPF diagnosis model using axial chest CT and DK, along with an optimality design criterion via a DK-enhanced loss function of deep learning. Four state-of-the-art two-dimensional convolutional neural network (2D-CNN) architectures (MobileNet, VGG16, ResNet-50, and DenseNet-121) and one baseline 2D-CNN are implemented to automatically diagnose IPF among ILD patients. Axial lung CT images are retrospectively acquired from 389 IPF patients and 700 non-IPF ILD patients in five multicenter clinical trials. To enrich the sample size and boost model performance, we sample 20 three-slice samples (triplets) from each CT scan, where these three slices are randomly selected from the top, middle, and bottom of both lungs respectively. Model performance is evaluated using a fivefold cross-validation, where each fold was stratified using a fixed proportion of IPF vs non-IPF. Using DK-enhanced loss function increases the model performance of the baseline CNN model from 0.77 to 0.89 in terms of study-wise accuracy. Four other well-developed models reach satisfactory model performance with an overall accuracy >0.95 but the benefits brought on by the DK-enhanced loss function is not noticeable. We believe this is the first attempt that (a) uses population-level DK with an optimal design criterion to train deep learning-based diagnostic models in an end-to-end manner and (b) focuses on patient-level IPF diagnosis. Further evaluation of using population-level DK on prospective studies is warranted and is underway.

Determination of split renal function in voluntary renal donors by multidetector computed tomography and nuclear renography: How well do they correlate?

BackgroundThe use of computed tomography (CT) for estimation of split renal function (SRF) has been reported previously. However, most of these studies have small samples, and many do not account for the renal attenuation at CT.ObjectiveThe aim of this study was to compare multidetector computed tomography (MDCT) volumetry-attenuation-based SRF with that obtained via Tc99m-diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy in voluntary renal donors.MethodsBetween January 2017 and January 2020, 526 voluntary renal donors were enrolled prospectively. All donors underwent contrast CT and DTPA scan before surgery. The semiautomatic region of interest (ROI) tool was applied slice by slice on axial CT images acquired in the arterial phase. The renal contour was drawn semiautomatically with mouse clicks around the renal parenchyma, and the renal volume was ascertained. Using renal volume and attenuation, SRF was determined and compared with results obtained at DTPA imaging.ResultsThe mean age was 44.91 ± 10.97 years (mean ± s.d.). There was no significant difference in SRF based on DTPA and MDCT volumetry for the left kidney (49.18% ± 3.40% vs. 49.15% ± 3.38%, p = 0.540) and for the right kidney (50.82% ± 3.40% vs. 50.86% ± 3.39%, p = 0.358). A very good correlation was observed between the two methods for the left kidney (r = 0.953, p = 0.000) and the right kidney (r = 0.955, p = 0.000). On simple linear regression analysis, 90.8% of DTPA SRF values for the left kidney and 91.3% of DTPA SRF values for the right kidney could be predicted correctly using the corresponding MDCT SRF values.ConclusionMDCT volumetry-attenuation-derived estimation of SRF for living renal donors could be an alternative to renal scintigraphy-based SRF estimation.

Computed tomography texture analysis of mandibular condylar bone marrow in diabetes mellitus patients.

Diabetes mellitus (DM) is associated with a broad range of complications, such as retinopathy, nephropathy, neuropathy, and cardiovascular disease. Therefore, predicting DM from head and neck images is a challenge for clinicians. The purpose of this study was to assess the mandibular condylar bone marrow in DM patients using computed tomography (CT) texture analysis. This retrospective study included 16 DM and age and sex matched 16 control patients (11 men, 5 women; mean age, 56.8 ± 14.4years; range 31-78years). Patients with Type I DM, prior history of taking bisphosphonates, osteoarthritis of the temporomandibular joint, and CT images with metal artifacts were excluded from this study. Bilateral mandibular condylar bone marrow was manually contoured on axial CT images. The presence or absence of DM is the primary predictor variable. Texture features of the region of interest was the outcome variable, that were analyzed using an open-access software, MaZda Ver.3.3. For each group, 20 features out of 279 parameters were selected with Fisher, probability of error and average correlation coefficient methods in MaZda. Bivariate statistics were computed with the Mann-Whitney U test and the P value was set at .05. One histogram feature, 15Gy level co-occurrence matrix features, and four gray level run length matrix features showed differences between the DM patients and non-DM patients (P < 0.05). Several texture features of the condyle demonstrated differences between the DM and non-DM patients. CT texture analysis may potentially detect DM from the condylar bone marrow.

Automatic detection and localization of COVID-19 pneumonia using axial computed tomography images and deep convolutional neural networks.

COVID‐19 was first reported as an unknown group of pneumonia in Wuhan City, Hubei province of China in late December of 2019. The rapid increase in the number of cases diagnosed with COVID‐19 and the lack of experienced radiologists can cause diagnostic errors in the interpretation of the images along with the exceptional workload occurring in this process. Therefore, the urgent development of automated diagnostic systems that can scan radiological images quickly and accurately is important in combating the pandemic. With this motivation, a deep convolutional neural network (CNN)‐based model that can automatically detect patterns related to lesions caused by COVID‐19 from chest computed tomography (CT) images is proposed in this study. In this context, the image ground‐truth regarding the COVID‐19 lesions scanned by the radiologist was evaluated as the main criteria of the segmentation process. A total of 16 040 CT image segments were obtained by applying segmentation to the raw 102 CT images. Then, 10 420 CT image segments related to healthy lung regions were labeled as COVID‐negative, and 5620 CT image segments, in which the findings related to the lesions were detected in various forms, were labeled as COVID‐positive. With the proposed CNN architecture, 93.26% diagnostic accuracy performance was achieved. The sensitivity and specificity performance metrics for the proposed automatic diagnosis model were 93.27% and 93.24%, respectively. Additionally, it has been shown that by scanning the small regions of the lungs, COVID‐19 pneumonia can be localized automatically with high resolution and the lesion densities can be successfully evaluated quantitatively.

Effect of contrast agent administration on water equivalent diameter in CT.

Water equivalent diameter (WED) is the preferred surrogate for patient size in computed tomography (CT). It is better than geometric size surrogates and patient weight/height/BMI/age because it correlates the best with x-ray attenuation. The administration of oral/IV contrast agents increases a patient's attenuation and should therefore increase WED. Here we study the clinically relevant effect of oral and IV contrast agent on WED. We pulled 1703 routine adult abdominal/pelvis cases acquired at 100, 120, and 140kV from our PACS under retrospective IRB approval. One hundred and forty cases cases had no oral or IV contrast (NONCON), 285 had just IV contrast (IV), 107 had just oral contrast (ORAL), and 1171 had both oral and IV contrast (BOTH). For each case, we measured the water equivalent and effective diameter (ED) from axial CT images. We plotted the WED versus the ED for each class of contrast. We used a linear regression model and omnibus F-test to determine if significant differences between WED distributions existed between the contrast groups for each kV. We then performed a post hoc analysis to determine if any significant differences existed in pairwise comparisons of the different contrast groups. Bonferroni correction was used to account for multiple comparisons. We found statistically significant changes at 100 and 120kV with a maximum change of 2.1mm. We measured a ~25mm spread (i.e., prediction interval) of WEDs within all four contrast groups. While our sample size was large enough to detect statistically significant differences between some of the contrast groups, the differences were clinically irrelevant when one considers that the change in size-specific dose estimate (SSDE) caused by our observations is roughly 1%.

The association of silicosis severity with pectoralis major muscle and subcutaneous fat volumes and the pulmonary artery/aorta ratio evaluated by CT.

Silicosis is an incurable occupational disease that sometimes rapidly progresses with fatal outcomes. We aimed to evaluate the association between disease severity and the change in the pectoralis major muscle volume (PMV), subcutaneous fat volume (SFV), and the pulmonary artery/aorta (P/Ao) ratio in patients with silicosis using computed tomography (CT). The study included 41 male silicosis patients and 41 control group subjects with available chest CT images. Using dedicated software, we measured PMV and SFV from the axial CT images. We calculated the P/Ao ratio and obtained body mass index (BMI) and forced expiratory volume/forced vital capacity (FEV1/FVC) results from hospital records. We used the chest X-ray profusion score according to the International Labor Organization (ILO) classification to evaluate the severity of the silicosis. The mean age was 33.5±4.4 and 34.7±4.7 years in the silicotic and control groups, respectively. The mean BMI, PMV, SFV, and P/Ao values significantly differed between the study and control groups (P = 0.0009, P < 0.0001, P < 0.0001, and P = 0.0029, respectively). According to the ILO classification, there were 12 silicosis patients in category 1, 13 in category 2, and 16 in category 3. A significant difference was found between disease categories in terms of PMV, SFV, P/Ao, BMI, and FEV1/FVC values (P = 0.0425, P = 0.0341, P = 0.0002, P = 0.0492, and P = 0.0004, respectively). Disease severity had a stronger association with decreased PMV and SFV and increased P/Ao ratios than BMI in patients with silicosis caused by denim sandblasting. Thus, CT evaluation might be a useful indicator of disease severity.

Diagnostic Yield of Axial Computed Tomography Scans for Pediatric Axial Skeletal Injuries.

Retrospective cohort study. To evaluate the diagnostic yield of computed tomography (CT) imaging of the axial skeleton in pediatric patients evaluated a level I trauma center. CT imaging has become ubiquitous in the assessment of axial skeletal injuries in trauma patients. This is a retrospective study from one Level I trauma center of patients undergoing CT imaging during pediatric trauma assessment. Medical records of pediatric trauma patients 18-year old and younger who underwent axial skeletal CT imaging from 2013 to 2015 were evaluated. The following were assessed: mechanism of injury, age, sex, race/ethnicity, presence of fracture, management of fracture. A total of 831 patients were assessed, there were 355 (42.7%) females and 476 males (57.3%) with an average age of 15.4 (2 mo-18 yrs). 588 (70.8%) were White, 164 (19.7%) were African-American, 12 (1.4%) were Asians, 67 (8.1%) other, and 46 (5.5%) identified as Hispanic. There were 45 patients (5.4%) who sustained 52 fractures. Common mechanisms were motor vehicle accidents (MVA) 28%, sports injuries (18%), and fall from height (15%). 35.9% of fractures were identified on plain radiographs. Nine injuries were treated surgically (one cervical, two thoracic, two lumbar, and four pelvic); three of these were identified on radiographs. From the 14 patients with cervical spine fractures none were detected on radiographs. In this large series of 831 pediatric patients undergoing axial CT imaging, the rate of axial fractures was 5.4%. The majority of these fractures were managed non-surgically. Only 35.9% of fractures were identified on radiographs.Level of Evidence: 3.

Use of tracheobronchial tree 3-dimensional printed model: does it improve trainees\u2019 understanding of segmentation anatomy? A prospective study

BackgroundThis prospective study investigated whether the use of 3D-printed model facilitates novice learning of radiology anatomy on multiplanar computed tomography (CT) when compared to traditional 2D-based learning tools. Specifically, whether the use of a 3D printed model improved interpretation of multiplanar CT tracheobronchial anatomy.MethodsThirty-one medical students (10F, 21 M) from years one to three were recruited, matched for gender and level of training and randomized to 2D or 3D group. Students underwent 20-min self-study session using 2D-printed image or 3D-printed model of the tracheobronchial tree. Immediately after, students answered 10 multiple-choice questions (Test 1) to identify tracheobronchial tree branches on multiplanar CT images. Two weeks later, identical test (Test 2) was used to assess retention of information. Mean scores of 2D and 3D groups were calculated. Student’s t test was used to compare mean differences in tests scores and analysis of variance (ANOVA) was used to assess the interaction of gender, CT imaging plane and time on test scores between the two groups.ResultsFor test 1, 2D group had higher mean score than 3D group although not statistically significant (7.69 and 7.43, p = 0.39). Mean scores for Test 2 were significantly lower than for Test 1 (7 and 7.57, p = 0.03) with mean score decline for 2D group (Test 1 = 7.69, Test 2 = 6.63, p = 0.03), and similar score for 3D group (Test 1 and 2 = 7.43). There was no statistically significant interaction of gender and test score over time. Significant interaction between group and time of test was found for axial CT images but not for coronal images.ConclusionsUse of a 3D-printed model of the tracheobronchial anatomy had no immediate advantage over traditional 2D-printed images for learning CT anatomy. However, use of a 3D model improved students’ ability to retain learned information, irrespective of gender.

A new prognostic marker in patients undergoing Hartmann's procedure for acute tumoral obstruction of the left colon.

In acute obstructive left-sided colorectal cancers (AOLCRC), damage to the colon wall may occur as a result of distension of the colon segments proximal to the tumor. In this study, we aimed to evaluate the relationship between the ratio of dilated colon diameter (CD) to lumbar vertebral corpus diameter on preoperative abdominal computed tomography (CT) scan in patients undergoing Hartmann's Procedure (HP) and post-operative complications. The tumor group consisted of 49 patients who underwent HP for AOLCRC under emergency conditions. The control group consisted of 49 age-and gender-matched individuals (compatible with tumor group) that had an abdominal CT due to pathologies outside the gastrointestinal tract and without a history of abdominal surgery. In both group, the ratios of the CD to the diameter of the first lumbar vertebra corpus (L1-VD) measured on axial CT images of each patient. These ratios were compared between groups. In the tumor group, the relationship between post-operative complications (Clavien-Dindo classification-major (grade ≥III), minor (grade <III)) and demographic characteristics, pre-operative biochemical values, comorbid diseases, tumor pathological stage, operation time, and colon segments' CD/L1-VD ratios was evaluated. The CD/L1-VD ratio in the tumor group was significantly higher than that of the control group (p<0.001). An increase in the pre-operative transverse and descending colon CD/L1-VD ratios in the tumor group were found to be a prognostic parameter for the development of major post-operative complications (p<0.001 and p=0.015, respectively), with the cut-off values as 1.52 and 1.21 (p=0.013 and p=0.042), respectively. The increase in the pre-operative transverse colon CD/L1-VD ratio was also associated with the increase in the blood urea level (p=0.044). A positive correlation was observed between the pre-operative blood urea levels and post-operative complications (p=0.015). Pre-operative transverse and descending colon CD/L1-VD ratios in AOLCRC are promising prognostic parameters for major postoperative complications.

Sectional Anatomy Quiz - VI.

This quiz is part of a series which aims to aid nuclear physicians in interpreting the computed tomography (CT) component of the single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies. The current quiz includes normal and pathological axial CT images at the level of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV). The SMV is normally located to the right of the SMA and is of a larger caliber. Various pathologies such as malignancy, infection or vascular disease can alter the position and/or appearance of the SMA, SMV and the surrounding anatomical structures present at this level. Understanding how normal anatomy is altered by pathology at this level will facilitate improved interpretation of abdominal CT images.

Circularity Index on Contrast-Enhanced Computed Tomography Helps Distinguish Fat-Poor Angiomyolipoma from Renal Cell Carcinoma: Retrospective Analyses of Histologically Proven 257 Small Renal Tumors Less Than 4 cm.

ObjectiveTo evaluate circularity as a quantitative shape factor of small renal tumor on computed tomography (CT) in differentiating fat-poor angiomyolipoma (AML) from renal cell carcinoma (RCC).Materials and MethodsIn 257 consecutive patients, 257 pathologically confirmed renal tumors (either AML or RCC less than 4 cm), which did not include visible fat on unenhanced CT, were retrospectively evaluated. A radiologist drew the tumor margin to measure the perimeter and area in all the contrast-enhanced axial CT images. In each image, a quantitative shape factor, circularity, was calculated using the following equation: 4 × π × (area ÷ perimeter2). The median circularity (circularity index) was adopted as a representative value in each tumor. The circularity index was compared between fat-poor AML and RCC, and the receiver operating characteristic (ROC) curve analysis was performed. Univariable and multivariable binary logistic regression analysis was performed to determine the independent predictor of fat-poor AML.ResultsOf the 257 tumors, 26 were AMLs and 231 were RCCs (184 clear cell RCCs, 25 papillary RCCs, and 22 chromophobe RCCs). The mean circularity index of AML was significantly lower than that of RCC (0.86 ± 0.04 vs. 0.93 ± 0.02, p < 0.001). The mean circularity index was not different between the subtypes of RCCs (0.93 ± 0.02, 0.92 ± 0.02, and 0.92 ± 0.02 for clear cell, papillary, and chromophobe RCCs, respectively, p = 0.210). The area under the ROC curve of circularity index was 0.924 for differentiating fat-poor AML from RCC. The sensitivity and specificity were 88.5% and 90.9%, respectively (cut-off, 0.90). Lower circularity index (≤ 0.9) was an independent predictor (odds ratio, 41.0; p < 0.001) for predicting fat-poor AML on multivariable logistic regression analysis.ConclusionCircularity is a useful quantitative shape factor of small renal tumor for differentiating fat-poor AML from RCC.

Sternalis muscle in jordanian population: a prevalence study and level of physicians’ awareness

Sternalis muscle (SM) is an anatomical variant that lies parallel to the sternum. It is present in (8%) of human population. Awareness about its presence during thoracic imaging is important, since it might be misdiagnosed as a tumor. This study is the first that discusses the prevalence of SM in the Jordanian population and document the level of awareness about SM among intern doctors and surgery and radiology residents. Our aims are to know the prevalence of SM in the Jordanian population, using thoracic multi-detector computerized tomography (CT) images, and to assess the awareness about SM among a sample of intern and resident Jordanian physicians. Random anonymous axial thoracic multi-detector CT images of 1,709 (801 females and 908 males) Jordanian patients, were examined for the presence or absence of unilateral and/or bilateral SM. A questionnaire aiming to identify SM was distributed among 175 intern doctors, 26 surgery resident and 28 radiology resident doctors, their answers were summarized. The prevalence of SM among Jordanians is 5.9%. The prevalence of unilateral SM is 2.1% on the right side of the thorax and 1.9% on the left side, bilateral prevalence was 1.8%. While 35.7% of the radiology residents could identify SM using CT and/or anatomy images, only 3.9% of surgery residents and none of the intern doctors could. We concluded that SM is present in the Jordanian population, with a prevalence of 5.9% which falls within the global average. Intern doctors and surgery and radiology residents are almost unaware and unfamiliar about SM.

Diaphragm Morphology Assessed by Computed Tomography in Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) is associated with abnormal skeletal muscle morphology and function. Objectives: To test the hypothesis that in vivo diaphragm muscle morphology assessed by computed tomography (CT) imaging would be associated with COPD severity, exacerbations, health status, and exercise capacity. Methods: The COPD Morphometry Study is a cross-sectional study that enrolled a clinical sample of smokers with COPD. Spirometry was performed and COPD severity was defined according to guidelines. Three-dimensional left hemidiaphragm morphology was segmented from contiguous axial CT images acquired at maximal inspiration, yielding quantitative measures of diaphragm CT density in Hounsfield units, dome height, and muscle volume. Exacerbations prompting pharmacotherapy or hospitalization in the preceding 12 months and St. George's Respiratory Questionnaire for COPD were assessed. Incremental symptom-limited cycle ergometry quantified peak oxygen uptake ([Formula: see text]o2Peak). Associations were adjusted for age, sex, body height, body mass index, and smoking status. Results: Among 65 smokers with COPD (75% male; [mean ± standard deviation (SD)] 56 ± 26 pack-years; forced expiratory volume in 1 second [FEV1] percentage predicted 55 ± 23%), mean diaphragm CT density was 3.1 ± 10 Hounsfield units, dome height was 5.2 ± 1.3 cm, and muscle volume was 57 ± 24 cm3. A 1-SD decrement in the diaphragm CT density was associated with 8.3% lower FEV1, 3.27-fold higher odds of exacerbation history, 9.7-point higher score on the St. George's Respiratory Questionnaire for COPD, and 2.5 ml/kg/min lower [Formula: see text]o2Peak. A 1-SD decrement in dome height was associated with 11% lower FEV1 and 1.3 ml/kg/min lower [Formula: see text]o2Peak. There were no associations with diaphragm volume observed. Conclusions: CT-assessed diaphragm morphology was associated with COPD severity, exacerbations, impaired health status, and exercise intolerance. The mechanisms and functional impact of lower diaphragm CT density merit investigation.

The Role of Weightbearing Computed Tomography Scan in Hallux Valgus.

Hyperpronation of the first metatarsal in hallux valgus (HV) is poorly understood by conventional weightbearing radiography. We aimed to evaluate this parameter using weightbearing computed tomography (WBCT) and to understand its association with other standard measurements. Retrospective evaluation of WBCT and weightbearing radiographs (WBXRs) was performed for 20 patients with HV feet and 20 controls with no such deformity. Axial computed tomography images of both groups were compared for the first metatarsal pronation angle (alpha angle) and tibial sesamoid subluxation (TSS) grades. The HV angle (HVA), first-second intermetatarsal angle (IMA), first metatarsal-medial cuneiform angle (MMCA), Meary's angle, and calcaneal pitch (CP) angle of the study and control groups were compared on both WBXR and the corresponding 2-dimensional images of WBCT. All measurements were independently performed by 1 musculoskeletal radiology fellow and 1 foot and ankle surgical fellow. Measurements were averaged and interobserver reliability was calculated. The HV group demonstrated significantly higher values for TSS grade (P < .001) but not for alpha angle (P = .121) compared with controls. Likewise, significantly elevated HVA and IMA were noted in the HV group on both imaging modalities, while no such differences were observed for the CP angle. Higher MMCA and Meary's angle in the HV group were evident only on WBXR (MMCA, P = .039; Meary's, P = .009) but not on WBCT (MMCA, P = .183; Meary's, P = .171).Among all, the receiver operating characteristic (ROC) curves demonstrated the greatest area under the curve (AUC) for HVA, followed by IMA. The alpha angle performed only just outside the range of chance (AUC, 0.65; 95% CI, 0.52-0.69). The Pearson's correlations of the alpha angle, in the HV group, revealed a significant linear relationship with TSS grade and with HVA on WBXR, and only trended toward a weak linear relationship with IMA and with HVA on WBCT. The alpha angle, a measure of abnormal hyperpronation of the first metatarsal, was an independent factor that may coexist with other parameters in HV, but in isolation had limited diagnostic utility. "Abnormal" alpha angles were even observed in individuals without HV. Increases in IMA and MMCA were not necessarily associated with similar increases in alpha angle, despite moderate correlations with TSS grade and HVA on WBXR. Nevertheless, the WBCT was a useful method for assessing hyperpronation and guiding surgical management in individual cases. Level III, retrospective comparative study.

Superior Mesenteric and Inferior Mesenteric Artery Diameters in Colorectal Cancer.

To compare the superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) diameters in colorectal cancer compared to control. Observational study. Taizhou Hospital, Zhejiang University, Taizhou, China, from March 2019 to June 2020. A total of 203 diagnosed colorectal cancer patients and 40 patients as control subjects were reviewed. Patients were divided into three groups based on tumor location as the right colon, left colon, and rectal groups. The diameters were measured on axial computed tomography images independently by two observers. The SMA diameter did not differ between the right colon and control groups (p=0.626). The IMA diameter was significantly higher in the left colon group than in the control group (p=0.002), but there was no significant difference in the IMA diameter between the different tumour stages (p=0.263). The IMA diameter was significantly higher in the rectal group than in the control group (p<0.001). There was a significant increase in the IMA diameter from stage I to stage II rectal cancers (p=0.022) and from stage II to stage III rectal cancers (p=0.003). The IMA diameter did not differ between stage III and IV rectal cancers (p=0.600). In locoregional rectal cancer patients, there was a significant correlation between the IMA diameter and tumour-node-metastasis stage (p<0.001, rs = 0.494). Patients with rectal cancer and left colon cancer have a wider IMA diameter than patients without colorectal cancer. IMA diameter can be a potential marker for locoregional staging of rectal cancer. Key Words: Superior mesenteric artery, Inferior mesenteric artery, Colorectal cancer, Markers, Diameter.

Assessment of Myosteatosis on Computed Tomography by Automatic Generation of a Muscle Quality Map Using a Web-Based Toolkit: Feasibility Study.

BackgroundMuscle quality is associated with fatty degeneration or infiltration of the muscle, which may be associated with decreased muscle function and increased disability.ObjectiveThe aim of this study is to evaluate the feasibility of automated quantitative measurements of the skeletal muscle on computed tomography (CT) images to assess normal-attenuation muscle and myosteatosis.MethodsWe developed a web-based toolkit to generate a muscle quality map by categorizing muscle components. First, automatic segmentation of the total abdominal muscle area (TAMA), visceral fat area, and subcutaneous fat area was performed using a predeveloped deep learning model on a single axial CT image at the L3 vertebral level. Second, the Hounsfield unit of each pixel in the TAMA was measured and categorized into 3 components: normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and inter/intramuscular adipose tissue (IMAT) area. The myosteatosis area was derived by adding the LAMA and IMAT area. We tested the feasibility of the toolkit using randomly selected healthy participants, comprising 6 different age groups (20 to 79 years). With stratification by sex, these indices were compared between age groups using 1-way analysis of variance (ANOVA). Correlations between the myosteatosis area or muscle densities and fat areas were analyzed using Pearson correlation coefficient r.ResultsA total of 240 healthy participants (135 men and 105 women) with 40 participants per age group were included in the study. In the 1-way ANOVA, the NAMA, LAMA, and IMAT were significantly different between the age groups in both male and female participants (P≤.004), whereas the TAMA showed a significant difference only in male participants (male, P<.001; female, P=.88). The myosteatosis area had a strong negative correlation with muscle densities (r=–0.833 to –0.894), a moderate positive correlation with visceral fat areas (r=0.607 to 0.669), and a weak positive correlation with the subcutaneous fat areas (r=0.305 to 0.441).ConclusionsThe automated web-based toolkit is feasible and enables quantitative CT assessment of myosteatosis, which can be a potential quantitative biomarker for evaluating structural and functional changes brought on by aging in the skeletal muscle.

Tibial Tubercle–Midepicondyle Distance Can Be a Better Index to Predict the Outcome of Medial Patellofemoral Ligament Reconstruction Than Tibial Tubercle-Trochlear Groove Distance

PurposeTo compare the clinical utility of tibial tubercle-midepicondyle (TT-ME) and tibial tubercle-trochlear groove (TT-TG) distances in predicting the risk for recurrent instability after isolated MPFL reconstruction.MethodsA consecutive series of patients with recurrent patellar dislocation who underwent isolated MPFL reconstruction made up the study population. The patients were followed for a minimum of 2 years. In assessment of surgical outcome, the patient was deemed to exhibit “postoperative recurrent patellar instability” when ≥1 of the following 3 conditions was identified: redislocation, positive apprehension sign, and positive J-sign (manifestation of abnormal patellar tracking). As for radiological parameters for position of the tibial tubercle, TT-ME distance (transverse distance between the tibial tubercle and midpoint of the transepicondylar line) and TT-TG distance were measured on axial computed tomography images. The clinical utility as a factor to predict the outcome of MPFL reconstruction was compared between the 2 distances using receiver operating characteristic (ROC) analysis. In addition, various radiological indices potentially influencing the surgical outcome were subjected to multivariable logistic regression analysis.ResultsWe examined 38 knees in 38 patients with a mean age at surgery of 17.6 years. Postoperative recurrent patellar instability was encountered in 8 of the 38 knees. The ROC curve analysis showed the TT-ME distance to be a significantly better indicator in predicting surgical outcome than the TT-TG distance (P = .001). The univariate analysis for radiological factors demonstrated that the TT-ME distance was significantly associated with postoperative recurrent patellar instability (odds ratio 1.42, P = .012) whereas all other factors including the TT-TG distance did not correlate with recurrent instability. The multivariable logistic regression analysis revealed that only the TT-ME distance was significantly associated with recurrent instability (P = .035).ConclusionsAnalysis of our patient population undergoing isolated MPFL reconstruction showed that the TT-ME distance was a significantly better indicator than the TT-TG distance to predict the risk for recurrent instability after isolated MPFL reconstruction performed for patellar instability.Level of EvidenceLevel IV, therapeutic case series.

Potential Risk of Thoracic Aorta Injury from Excessively Long Right Pedicle Screws in Patients with Left Thoracic Scoliosis: A Computed Tomography Image Study

We sought to investigate the changed position of thoracic aorta relative to spine in patients with left thoracic scoliosis and to analyze the potential risks of thoracic aorta injury from pedicle screw insertion in these patients. Twenty patients with left thoracic scoliosis (Group A) and 15 normal subjects with a straight spine (Group B) were included. Axial computed tomography images from T5 to T12 of all these subjects were obtained to measure the aorta-vertebral angle. The percentages of thoracic aorta located anteriorly to the screw trajectory were calculated on both the left and right sides. The average aorta-vertebral angle in Group A was significantly larger than that in Group B at each level (P < 0.05) except T5. In Group A, both left and right pedicle screws might pose threats to the thoracic aorta. The percentages of aortas at risk from the right pedicle screw were high in the apical region. However, in Group B, only the left pedicle screw might pose threats to the aorta. No aorta was found to be at risk of injury from right pedicle screw insertion in Group B. The thoracic aorta often lies anteriorly to the left pedicle screw trajectory in normal subjects, especially in the lower thoracic region. However, the thoracic aorta moves to the right side in patients with left thoracic scoliosis, making a large proportion of patients at risk of injury from right pedicle screw insertion in the apical region.

Accuracy of EOS Imaging Technology in Comparison to Computed Tomography in the Assessment of Vertebral Rotational Orientation in Instrumented Spines in Adolescent Idiopathic Scoliosis.

Retrospective radiographic reliability study. The aim of this study was to assess the validity of EOS 3D imaging technology in the determination of vertebral rotations in the spine of patients with previous instrumentation. There is a lack of evidence on the accuracy of vertebral rotational measurement using EOS 3D morphological analysis in the instrumented spine. A retrospective review of 31 patients with adolescent idiopathic scoliosis (AIS) who underwent instrumented fusion and postoperative computed tomography (CT) scans of the spine was performed. Vertebral rotations of the apex vertebra, the uppermost (UIV) and lowermost (LIV) instrumented vertebra, the noninstrumented vertebra one level cranial to the UIV (UIV + 1) and one level caudal to LIV (LIV + 1) were determined using EOS 3D reconstruction. The vertebral rotation was also measured using reformatted CT axial images. Relative vertebral rotational difference (VRD) were calculated for UIV to apex, UIV + 1 to apex, LIV to apex, LIV + 1 to apex, UIV to LIV and UIV + 1 to LIV + 1. Paired t tests were used to compare the VRD measured using the two different imagining modalities. For values where P > 0.05, the Bland-Altman plot was used to assess the agreement between the measures. Interclass correlation (ICC) was used to determine interobserver and intraobserver reliabilities of EOS and CT measurements. EOS analysis of relative VRD was found to be significantly different from that of CT for UIV to apex (P = 0.006) and UIV + 1 to apex (P = 0.003). No significant differences were found for LIV to apex (P = 0.06), LIV + 1 to apex (P = 0.06), UIV to LIV (P = 0.59) and UIV + 1 to LIV + 1 (P = 0.64). However, Bland-Altman plots showed that agreement was poor, and variance was beyond acceptable. ICC showed good interobserver and good to very good intraobserver reliability for EOS. EOS 3D morphological analysis of VRD in the instrumented levels of the spine demonstrated significant difference and unacceptable variance in comparison to CT measurement.Level of Evidence: 4.

S2868 A Serendipitous Identification of Contained Duodenal Perforation

INTRODUCTION: Peptic ulcer disease (PUD) is a condition defined by defects in the gastric and/or duodenal mucosa that extend through the muscularis mucosa. Sequalae of untreated PUD include gastrointestinal (GI) bleeding, gastric outlet obstruction and perforation. Typical presenting symptoms of upper GI perforation include sudden onset of severe sharp abdominal pain, peritoneal signs and severe sepsis or septic shock. CASE DESCRIPTION/METHODS: We present a case of a 71-year-old woman with chronic back pain on celecoxib who presented with mild progressively worsening abdominal pain, non-bilious/non-bloody vomiting and decreased oral intake. Abdomen was benign and initial laboratory tests were unrevealing. Computed tomography (CT) revealed a 6.6 cm heterogeneous complex cystic/solid mass originating from the second portion of duodenum with large exophytic component, and abutting the pancreatic head, liver, proximal duodenum, portal vein and inferior vena cava (Figure 1). Esophagogastroduodenoscopy (EGD) revealed a fistulous tract along the duodenal sweep leading into an extra-luminal cavity (Figure 2) and multiple Forrest Class III duodenal bulb ulcers. Intraprocedural surgical consultation was obtained and a decision was made to proceed with endoscopic ultrasonography (EUS). EUS revealed a 40.2 × 27.3 mm hypoechoic heterogeneous porta-hepatis lesion with ill-defined borders, containing a well-circumscribed anechoic component consistent with contained perforation cavity. Fine needle biopsy (FNB) was performed with pathology revealing a grade 1 well-differentiated duodenal neuroendocrine tumor (D-NET) with immunohistochemical stains positive for synaptophysin, negative for chromogranin A and less than 1% positivity for Ki67 (Figure 3). Of note, serum chromogranin A level was markedly elevated to 1,105 ng/mL (normal: < 93 ng/mL). A pancreaticoduodenectomy was advised, however, patient declined. DISCUSSION: Although most common cause of duodenal perforations is PUD secondary to Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs) use, other etiologies include diverticulum, regional infections, autoimmune conditions, ischemia, Bouveret syndrome, chemotherapy and localized tumors. NETs account for 0.5% of all cancers and D-NETs comprise 5-8% of all GI-NET. Although contained GI perforations have atypical presentations, one should always keep tumor on the differential. To our knowledge, this is the first case report of D-NET leading to perforation.Figure 1.: Intravenous and oral contrast enhanced axial (A) and coronal (B) CT images of the abdomen demonstrating a complex heterogeneous and cystic mass in the porta hepatis region. The mass is interposed between and inseparable from the duodenum (straight white arrow) and head of the pancreas (curved white arrow). The inferior aspect of the mass is heterogeneous (white arrowhead) with areas of hyper-intensity compatible with tumor enhancement. The superior aspect of the mass is cystic with complex fluid attenuation (black arrowhead) consistent with the histopathologic findings of perforation and hematoma.Figure 2Figure 3