Dynamic Computed Tomography Scans Research Articles

Dynamic liver volume change in predicting hepatic decompensation and long-term effects of stereotactic body radiation therapy.

This study aimed to investigate the association between liver volume change and hepatic decompensation and compare the risk of hepatic decompensation in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) who underwent stereotactic body radiation therapy (SBRT). A retrospective review of SBRT-treated HCC and compensated LC without HCC patients was conducted. Liver volume was measured using auto-segmentation software on liver dynamic computed tomography scans. The decompensation event was defined as the first occurrence of refractory ascites, esophageal variceal bleeding, hepatic encephalopathy, or spontaneous bacterial peritonitis. We evaluated the association between the rate of liver volume decrease and hepatic decompensation and compared decompensation events between the SBRT and LC cohorts using propensity score matching. A total of 138 patients from the SBRT cohort and 488 from the LC cohort were analyzed. The rate of liver volume decrease was associated with the risk of decompensation events in both cohorts. The 3-year rate of decompensation events was significantly higher in the group with a liver volume decreasing rate>7%/year compared with the group with a rate<7%/year. In the propensity score-matched cohort, the 3-year rate of decompensation events after a single session of SBRT was not significantly different from that in the LC cohort. The rate of liver volume decrease was significantly associated with the risk of hepatic decompensation in both HCC patients who received SBRT and LC patients. A single session of SBRT for HCC did not result in a higher decompensation rate compared with LC.

A Staged Approach for Surgical Management of Basilar Invagination

BACKGROUND AND OBJECTIVES: Patients with basilar invagination (BI) can be treated with several surgical options, ranging from simple posterior decompression to circumferential decompression and fusion. Here, we aimed at examining the indications and outcomes associated with these surgical strategies to devise a staged algorithm for managing BI. METHODS: We conducted a retrospective cohort study in 2 neurosurgical centers and included patients with a BI, as defined by a position of the dens tip at least 5 mm above the Chamberlain line. Other craniovertebral junction anomalies, such as atlas assimilation, platybasia, and Chiari malformations, were documented. C1-C2 stability was assessed with a dynamic computed tomography scan. RESULTS: We included 30 patients with BI with a mean follow-up of 56 months (min = 12, max = 166). Posterior decompression and fusion (n = 8) was only performed in cases of obvious atlanto-axial instability (eg, increased atlanto-dental interval or hypermobility on flexion/extension), while anterior decompression (transoral or transnasal) was reserved to patients with lower cranial nerves deficits (eg, swallowing dysfunction) and irreducible anterior compression (n = 9). Patients with posterior signs (eg, Valsalva headaches) or myelopathy but without C1-C2 instability nor anterior signs were managed with an isolated foramen magnum decompression, with or without duraplasty (n = 13). Complications were more frequent for combined procedures, including neurological deterioriation (n = 4) and tracheostomy (n = 2), but reinterventions were more likely in patients undergoing posterior decompression alone (n = 3). CONCLUSION: Patient selection is key to determine the appropriate surgical strategy for BI: In our experience, combined approaches are only needed for patients with irreducible and symptomatic anterior compression, while fusion should be restricted to patient with obvious signs of atlanto-axial instability. Other BI patients can be managed by foramen magnum decompression alone to minimize surgical morbidity.

Automated Liver Volumetry and Hepatic Steatosis Quantification with Magnetic Resonance Imaging Proton Density Fat Fraction

BackgroundPreoperative imaging evaluation of liver volume and hepatic steatosis for the donor affects transplantation outcomes. However, computed tomography (CT) for liver volumetry and magnetic resonance spectroscopy (MRS) for hepatic steatosis are time consuming. Therefore, we investigated the correlation of automated 3D-multi-echo-Dixon sequence magnetic resonance imaging (ME-Dixon MRI) and its derived proton density fat fraction (MRI-PDFF) with CT liver volumetry and MRS hepatic steatosis measurements in living liver donors. MethodsThis retrospective cross-sectional study was conducted from December 2017 to November 2022. We enrolled donors who received a dynamic CT scan and an MRI exam within 2 days. First, the CT volumetry was processed semiautomatically using commercial software, and ME-Dixon MRI volumetry was automatically measured using an embedded sequence. Next, the signal intensity of MRI-PDFF volumetric data was correlated with MRS as the gold standard. ResultsWe included the 165 living donors. The total liver volume of ME-Dixon MRI was significantly correlated with CT (r = 0.913, p < 0.001). The fat percentage measured using MRI-PDFF revealed a strong correlation between automatic segmental volume and MRS (r = 0.705, p < 0.001). Furthermore, the hepatic steatosis group (MRS ≥ 5%) had a strong correlation than the non–hepatic steatosis group (MRS < 5%) in both volumetric (r = 0.906 vs. r = 0.887) and fat fraction analysis (r = 0.779 vs. r = 0.338). ConclusionAutomated ME-Dixon MRI liver volumetry and MRI-PDFF were strongly correlated with CT liver volumetry and MRS hepatic steatosis measurements, especially in donors with hepatic steatosis.

Application of CD34 expression combined with three-phase dynamic contrast-enhanced computed tomography scanning in preoperative staging of gastric cancer.

Accurate preoperative staging of gastric cancer (GC), a common malignant tumor worldwide, is critical for appropriate treatment plans and prognosis. Dynamic three-phase enhanced computed tomography (CT) scanning for preoperative staging of GC has limitations in evaluating tumor angiogenesis. CD34, a marker on vascular endothelial cell surfaces, is promising in evaluating tumor angiogenesis. We explored the value of their combination for preoperative staging of GC to improve the efficacy and prognosis of patients with GC. To explore the evaluation value of CD34 expression + dynamic three-phase enhanced CT scanning in preoperative staging of GC. Medical records of 106 patients with GC treated at the First People's Hospital of Lianyungang between February 2021 and January 2023 were retrospectively studied. All patients underwent three-phase dynamic contrast-enhanced CT scanning before surgery, and CD34 was detected in gastroscopic biopsy specimens. Using surgical and pathological results as the gold standard, the diagnostic results of three-phase dynamic contrast-enhanced CT scanning at different T and N stages were analyzed, and the expression of CD34-marked microvessel density (MVD) at different T and N stages was determined. The specificity and sensitivity of three-phase dynamic contrast-enhanced CT and CD34 in T and N staging were calculated; those of the combined diagnosis of the two were evaluated in parallel. Independent factors affecting lymph node metastasis were analyzed using multiple logistic regression. The accuracy of three-phase dynamic contrast-enhanced CT scanning in diagnosing stages T1, T2, T3 and T4 were 68.00%, 75.00%, 79.41%, and 73.68%, respectively, and for diagnosing stages N0, N1, N2, and N3 were 75.68%, 74.07%, 85.00%, and 77.27%, respectively. CD34-marked MVD expression increased with increasing T and N stages. Specificity and sensitivity of three-phase dynamic contrast-enhanced CT in T staging were 86.79% and 88.68%; for N staging, 89.06% and 92.86%; for CD34 in T staging, 64.15% and 88.68%; and for CD34 in N staging, 84.38% and 78.57%, respectively. Specificity and sensitivity of joint diagnosis in T staging were 55.68% and 98.72%, and N staging were 75.15% and 98.47%, respectively, with the area under the curve for diagnosis improving accordingly. According to multivariate analysis, a longer tumor diameter, higher pathological T stage, lower differentiation degree, and higher expression of CD34-marked MVD were independent risk factors for lymph node metastasis in patients with GC. With high accuracy in preoperatively determining the invasion depth and lymph node metastasis of GC, CD34 expression and three-phase dynamic contrast-enhanced CT can provide a reliable basis for surgical resection.

Length Changes of the Medial Patellofemoral Ligament During In Vivo Knee Motion: An Evaluation Using Dynamic Computed Tomography

Background: Medial patellofemoral ligament (MPFL) reconstruction is associated with high complication rates because of graft overloading from incorrect graft positioning. To improve clinical outcomes, it is crucial to gain a better understanding of MPFL elongation patterns. Purpose: To assess MPFL length changes in healthy knees from 0° to 90° of dynamic flexion and their relationship with anatomic parameters of the patellofemoral joint. Study Design: Descriptive laboratory study. Methods: Dynamic computed tomography scans of an active flexion-extension-flexion movement in 115 knees from 63 healthy participants were evaluated to construct knee joint models. Using these models, the MPFL length was measured as the shortest wrapping path from the Schöttle point on the femur to 3 insertion points on the superomedial border of the patella (proximal, central, and distal). MPFL length changes (%) relative to the length in full extension were calculated, and their correlations with the tibial tuberosity–trochlear groove distance, Caton-Deschamps index, and lateral trochlear inclination were analyzed. Results: The proximal fiber was the longest in full extension and progressively decreased to a median length of −6.0% at 90° of flexion. The central fiber exhibited the most isometric pattern during knee flexion, showing a median maximal decrease of 2.8% relative to the full extension length and no evident elongation. The distal fiber first slightly decreased in length but increased at deeper flexion angles. The median overall length changes were 4.6, 4.7, and 5.7 mm for the proximal, central, and distal patellar insertion, respectively. These values were either not or very weakly correlated with the tibial tuberosity–trochlear groove distance, Caton-Deschamps index, and lateral trochlear inclination when the anatomic parameters were within the healthy range. Conclusion: The median MPFL length changed by approximately 5 mm between 0° and 90° of flexion. Proximally, the length continuously decreased, indicating slackening behavior. Distally, the length increased at deeper flexion angles, indicating tightening behavior. Clinical Relevance: In MPFL reconstruction techniques utilizing the Schöttle point to establish the femoral insertion, one should avoid distal patellar insertion, as it causes elongation of the ligament, which may increase the risk for complications due to overloading.

A Novel Observational Strategy for Nonfunctional Pancreatic Neuroendocrine Neoplasms With Texture Analysis: A Multicenter Retrospective Study.

Surgical resection is recommended for nonfunctional pancreatic neuroendocrine neoplasms (NF-pNENs). However, metastasis is rare in patients with small lesions with histological grade 1 (G1); thus, observation is an optional treatment approach for small NF-pNENs. Texture analysis (TA) is an imaging analysis mode for quantification of heterogeneity by extracting quantitative parameters from images. We retrospectively evaluated the utility of TA in predicting histological grade of resected NF-pNENs in a multicenter retrospective study. The utility of TA in preoperative prediction of grade were evaluated with 29 patients treated by pancreatectomy for NF-pNEN who underwent preoperative dynamic computed tomography scan between January 1, 2013 and December 31, 2020 at three hospitals affiliated with the Jikei University School of Medicine. TA was performed with dedicated software for medical imaging processing for determining histological tumor grade using dynamic computed tomography images. Histological tumor grades based on the 2017 World Health Organization Classification for Pancreatic Neuroendocrine Neoplasms were grade 1, 2 and 3 in 18, 10 and one patient, respectively. Preoperative grades by TA were 1 and 2/3 in 15 and 14 patients, respectively. The sensitivity, specificity and area under the curve for TA-oriented grade 1 lesions were 1.00, 0.889 and 0.965 (95% confidence interval=0.901-1.000), respectively. TA is useful for predicting grade 2/3 NF-pNEN and can provide a safe option for observation for patients with small grade 1 lesions.

Quantitative Analysis of Brain CT Perfusion in Healthy Beagle Dogs: A Pilot Study.

Brain computed tomography (CT) perfusion is a technique that allows for the fast evaluation of cerebral hemodynamics. However, quantitative studies of brain CT perfusion in veterinary medicine are lacking. The purpose of this study was to investigate the normal range of perfusion determined via CT in brains of healthy dogs and to compare values between white matter and gray matter, differences in aging, and each hemisphere. Nine intact male beagle dogs were prospectively examined using dynamic CT scanning and post-processing for brain perfusion. Regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), mean transit time, and time to peak were calculated. Tissue ROIs were drawn in the gray matter and white matter of the frontal, temporal, parietal, and occipital lobes; caudate nucleus; thalamus; piriform lobe; hippocampus; and cerebellum. Significant differences were observed between the white matter regions and gray matter regions for rCBV and rCBF (p < 0.05). However, no significant differences were identified between hemispheres and between young and old groups in brain regions. The findings obtained in this study involving healthy beagle dogs might serve as a reference for regional CT perfusion values in specific brain regions. These results may aid in the characterization of various brain diseases in dogs.

Volumetric versus distortional deformation in rat lungs.

There are several lung diseases that lead to alterations in regional lung mechanics, including acute respiratory distress syndrome. Such alterations can lead to localized underventilation of the affected areas resulting in the overdistension of the surrounding healthy regions. They can also lead to the surrounding alveoli expanding unevenly or distorting. Therefore, the quantification of the regional deformation in the lungs offers insights into identifying the regions at risk of lung injury. Although few recent studies have developed image processing techniques to quantify the regional volumetric deformation in the lung from dynamic imaging, the presence and extent of distortional deformation in the lung, and its correlation with volumetric deformation, remain poorly understood. In this study, we present a method that uses the four-dimensional displacement field obtained from image registration to quantify both regional volumetric and distortional deformation in the lung. We used dynamic computed tomography scans in a healthy rat over the course of one respiratory cycle in free breathing. Non-rigid image registration was performed to quantify voxel displacement during respiration. The deformation gradient was calculated using the displacement field and its determinant was used to quantify regional volumetric deformation. Regional distortion was calculated as the ratio of maximum to minimum principal stretches using the isochoric part of the Cauchy green tensor. We found an inverse correlation between volumetric strains and distortion indicating that poorly expanding alveoli tend to experience larger distortion. The combination of regional volumetric strains and distortion may serve as high-fidelity biomarkers to identify the regions at risk of most adverse lung injuries.

Reproducibility and repeatability of a semi-automated pipeline to quantify trapeziometacarpal joint angles using dynamic computed tomography

BackgroundThe trapeziometacarpal (TMC) joint is a mechanically complex joint and is commonly affected by musculoskeletal diseases such as osteoarthritis. Quantifying in vivo TMC joint biomechanics, such as joint angles, with traditional reflective marker-based methods can be difficult due to the joint’s location in the hand. Dynamic computed tomography (CT) can facilitate the quantification of TMC joint motion by continuously capturing three-dimensional volumes over time. However, post-processing of dynamic CT datasets can be time intensive and automated methods are needed to reduce processing times to allow for application to larger clinical studies. The purpose of this work is to introduce a fast, semi-automated pipeline to quantify joint angles from dynamic CT scans of the TMC joint and evaluate the associated error in joint angle and translation computation by means of a reproducibility and repeatability study.MethodsTen cadaveric hands were scanned with dynamic CT using a passive motion device to move thumbs in a radial abduction–adduction motion. Static CT scans and high-resolution peripheral quantitative CT scans were also acquired to generate high-resolution bone meshes. Abduction–adduction, flexion–extension, and axial rotation angles were computed using a joint coordinate system. Reproducibility and repeatability were assessed using intraclass correlation coefficients, Bland–Altman analysis, and root mean square errors. Target registration errors were computed to evaluate errors associated with image registration.ResultsWe found good repeatability for flexion–extension, abduction–adduction, and axial rotation angles. Reproducibility was moderate for all three angles. Joint translations exhibited greater repeatability than reproducibility. Specimens with greater joint degeneration had lower repeatability and reproducibility. We found that the difference in resulting joint angles and translations were likely due to differences in segment coordinate system definition between multiple raters, rather than due to registration errors.ConclusionsThe proposed semi-automatic processing pipeline was fast, repeatable, and moderately reproducible when quantifying TMC joint angles and translations. This work provides a range of errors for TMC joint angles from dynamic CT scans using manually selected anatomical landmarks.

Radiographic Evaluation of Carpal Mechanics and the Scapholunate Angle in a Clenched Fist with Dynamic Computed Tomography Imaging

The long-term consequences of injuries to the scapholunate joint can severely limit hand function, and the potential for posttraumatic deformity makes early recognition of these injuries important. The purpose of this study was to evaluate the motion of the scapholunate joint in normal wrists through the radial and ulnar deviation using novel dynamic computed tomography (CT) imaging. Fifteen participants consented to have their uninjured wrists scanned. A protocol was designed to ensure adequate time, yet limited exposure, for volunteers. Participants began with the hand in a relaxed fist position and then proceeded to clench the hand in a full fist and relax. Once relaxed again, the wrist was maximally ulnarly deviated and then maximally radially deviated in a fluid motion. Dynamic CT imaging was captured throughout the range of motion. The scapholunate angle was measured on dynamic wrist images. The mean range of the scapholunate angle that the wrists moved through was 37.2°-45.9°, and the mean midpoint angle was 41.2° ± 0.4°. All wrists had small, measurable differences in the scapholunate angle when moving from the maximum ulnar deviation to the maximal radial deviation. The average maximum angle change through the range is 11.7°, whereas the average minimum angle change was 0.9°. In this study, scapholunate angle calculations using dynamic wrist CT scans were within the range of accepted normal for the angle in uninjured wrists. With the increased focus on dynamic imaging for wrist motion, it may be possible to derive a standardized protocol for mapping the carpal motion that is clinically applicable and reproducible. Diagnostic IV.

Prediction of Aortic Contrast Enhancement on Dynamic Hepatic Computed Tomography-Performance Comparison of Machine Learning Methods and Simulation Software.

The aim of this study was to compare prediction ability between ensemble machine learning (ML) methods and simulation software for aortic contrast enhancement on dynamic hepatic computed tomography. We divided 339 human hepatic dynamic computed tomography scans into 2 groups. One group consisted of 279 scans used to create cross-validation data sets, the other group of 60 scans were used as test data sets. To evaluate the effect of the patient characteristics on enhancement, we calculated changes in the contrast medium dose per enhancement of the abdominal aorta in the hepatic arterial phase. The parameters for ML were the patient sex, age, height, body weight, body mass index, and cardiac output. We trained 9 ML regressors by applying 5-fold cross-validation, integrated the predictions of all ML regressors for ensemble learning and the simulations, and used the training and test data to compare their Pearson correlation coefficients. Comparison of different ML methods showed that the Pearson correlation coefficient for the real and predicted contrast medium dose per enhancement of the abdominal aorta was highest with ensemble ML (r = 0.786). It was higher than that obtained with the simulation software (r = 0.350). With ensemble ML, the Bland-Altman limit of agreement [mean difference, 5.26 Hounsfield units (HU); 95% limit of agreement, -112.88 to 123.40 HU] was narrower than that obtained with the simulation software (mean difference, 11.70 HU; 95% limit of agreement, -164.71 to 188.11 HU). The performance for predicting contrast enhancement of the abdominal aorta in the hepatic arterial phase was higher with ensemble ML than with the simulation software.

Application of dynamic CT scan in the three-dimensional dynamic morphology changes of laryngeal soft tissue in unilateral vocal fold paralysis patients

Objective: To explore the dynamic changes of three-dimensional morphology of laryngeal soft tissue and its clinical value in the unilateral vocal fold paralysis (UVFP) patients through dynamic CT scanning during the process from inspiration to phonation. Methods: From October 2017 to July 2019, a retrospective study was performed in 18 patients with UVFP (10 males and 8 females with the range of age from 29 to 75 years old) and 10 normal subjects (5 males and 5 females with the range of age from 25 to 58 years old) in Department of Voice-Otolaryngology Head and Neck Surgery, Section Two, Zhongshan Hospital Xiamen University. The laryngeal dynamic computed tomography (CT) of cine mode was performed. Ten dynamic sequence images of vocal folds movements were obtained during the process from inspiration to phonation. Based on the dynamic changes of glottic area and the displacement of cricoid cartilage. The above dynamic sequence images were divided into inspiratory phase and phonation phase as well as open phase and closed phase. The soft tissue parameters were measured respectively, including vocal folds length, width, thickness and subglottal convergence angle. Independent-sample t test was used to analyze between UVFP group and control group. Results: During the process from inspiration to phonation, the morphology of vocal folds in control group was relatively stable at inspiratory phase and closed phase in phonation. When open phase and closed phase of phonation were switching, the morphology of vocal folds changed obviously. The length of vocal folds became longer (1.19±0.10) mm, the width became wider (2.19±0.17) mm, the thickness became thinner (2.66±0.56) mm, and the subglottal convergence angle decreased (31.45±4.78)°. Compared with the controll group, in the open phase, the thickness and width of the vocal fold on affected side in the UVFP group were thinner (t=10.25, P<0.001) and wider (t=5.25, P<0.001).While in the closed phase, the subglottal convergence angle was larger (t=4.41, P=0.001).The width of the healthy side vocal fold in the UVFP was wider (t=2.54, P=0.026) than that in the control group. The differences in other parameters were not statistically significant. Conclusions: Dynamic laryngeal CT scanning provides a simple and non-invasive method for the objective and quantitative measurement of the dynamic changes of laryngeal morphology from inspiration to phonation. Compared with the control group, the characteristic dynamic changes among UVFP were observed during this particular process, which included changes of subglottal convergence angle and thickness of vocal muscle due to denervation. In addition, in UVFP group, the width of the vocal fold healthy side in the closed phase may be used to assess its compensatory function.

Functional Results of Arthroscopic Treatment in Patients With Femoroacetabular and Subspine Impingement Diagnosed With a 3-Dimensional Dynamic Study

PurposeTo describe the functional results of arthroscopic treatment in patients with femoroacetabular impingement (FAI) and subspine impingement (SSI) evaluated with a 3-dimensional (3D) dynamic study.MethodsThis was a retrospective observational study of patients with a diagnosis of FAI and SSI, evaluated with a 3D dynamic computed tomography scan with Move Forward software, who underwent hip arthroscopy between February 2015 and December 2017. Measurements of the alpha angle, femoral anteversion, acetabular anteversion, lateral center-edge angle, and Tönnis angle were extracted from the 3D dynamic study. Functionality was evaluated using the Western Ontario McMaster Universities Osteoarthritis Index before and 12 months after surgery.ResultsWe analyzed 22 hips in 17 patients (9 female and 8 male patients) with an average age of 34.6 ± 14.3 years. Of the 22 hips, 15 had cam morphology, 6 had mixed morphology, and 1 had pincer morphology. Of the hips, 11 had a type I spine, 10 had type II, and 1 had type III. The average alpha angle, Tönnis angle, femoral anteversion, and acetabular anteversion were 61.9° ± 11.1°, 2.5° ± 6.4°, 8.8° ± 6.8°, and 15.1° ± 7.1°, respectively. The median lateral center-edge angle was 38.1° (interquartile range, 32.6°-43.5°). At 1-year follow-up, a decrease in the Western Ontario McMaster Universities Osteoarthritis Index score (P = .001) and an increase in the flexion angle (P < .001) were observed. No cases needed posterior surgical revision because of persistent pain.ConclusionsArthroscopic treatment provides symptom relief and good functional results in patients with FAI and SSI.Level of EvidenceLevel IV, therapeutic case series.

The Effects of Positive End-Expiratory Pressure on Transpulmonary Pressure and Recruitment-Derecruitment During Neurally Adjusted Ventilator Assist: A Continuous Computed Tomography Study in an Animal Model of Acute Respiratory Distress Syndrome.

BackgroundWhether spontaneous breathing (SB) should be used in early acute respiratory distress syndrome (ARDS) is questioned because it may cause ventilator-induced lung injury (VILI) by tidal high strain/stress and recruitment/derecruitment (R/D). However, SB has shown beneficial effects when used appropriately. We hypothesized that high levels of positive end-expiratory pressure (PEEP), during assisted SB, would prevent tidal R/D, reducing ventilatory variation and respiratory rate while potentially increasing transpulmonary pressure (PTP). The aim was to test this hypothesis in experimental mild ARDS during continuous SB using neurally adjusted ventilator assist (NAVA) and uninterrupted computed tomography (CT) exposure.MethodsMild experimental ARDS (PaO2/FiO2-ratio of 250) was induced in anesthetized pigs (n = 5), ventilated using uninterrupted NAVA. PEEP was changed in steps of 3 cmH2O, from 0 to 15 and back to 0 cmH2O. Dynamic CT scans, ventilatory parameters, and esophageal pressure were acquired simultaneously. PTP and R/D were calculated and compared among PEEP levels.ResultsWhen increasing PEEP from 0 to 15 cmH2O, tidal R/D decreased from 4.3 ± 5.9 to 1.1 ± 0.7% (p < 0.01), breath-to-breath variability decreased, and PTP increased from 11.4 ± 3.7 to 29.7 ± 14.1 cmH2O (R2 = 0.96).ConclusionThis study shows that injurious phenomena like R/D and high PTP are present in NAVA at the two extremes of the PEEP spectrum. Willing to titrate PEEP to limit these phenomena, the physician must choose the best compromise between restraining the R/D or PTP.

Contrast Material Injection Protocol With the Dose Determined According to Lean Body Weight at Hepatic Dynamic Computed Tomography: Comparison Among Patients With Different Body Mass Indices.

The objective of this study was to compare enhancement of the aorta and liver on hepatic dynamic computed tomography scans acquired with contrast material doses based on the lean body weight (LBW) or the total body weight (TBW). We randomly divided 529 patients (279 men, 250 women; median age, 66 years) scheduled for hepatic dynamic computed tomography into 2 groups. The LBW patients (n = 278) were injected with 679 mg iodine/kg (men) or 762 mg iodine/kg (women). The TBW group (n = 251) was injected with 600 mg iodine/kg TBW. Each group was subdivided into the 3 classes based on the body mass index (BMI; low, normal, high). Aortic enhancement during the hepatic arterial phase and hepatic enhancement during the portal venous phase was compared. The aortic and hepatic equivalence margins were 100 and 20 Hounsfield units, respectively. Comparison of the median iodine dose in patients with a normal or high BMI showed that it was significantly lower under the LBW protocol than the TBW protocol (558.2 and 507.0 mg iodine/kg, P < 0.001, respectively). However, in patients with a low BMI, the LBW protocol delivered a significantly higher dose than the TBW protocol (620.7 vs 600.0 mg iodine/kg, P < 0.001). The 95% confidence interval for the difference in aortic and hepatic enhancement between the 2 protocols was within the range of the predetermined equivalence margins in all BMI subgroups. Contrast enhancement was equivalent under both protocols. The LBW protocol can avoid iodine overdosing, especially in patients with a high BMI.

Impact of transient hepatic attenuation differences on computed tomography scans in the diagnosis of acute gangrenous cholecystitis.

We examined the utility of transient hepatic attenuation differences (THADs) detected in the arterial phase of computed tomography for the diagnosis of acute gangrenous cholecystitis (AGC). We examined 83 consecutive patients who underwent cholecystectomy within 72h of undergoing three-phase dynamic computed tomography scans for acute cholecystitis between 2009 and 2018 (histopathological examination later confirmed 42 with AGC, 41 without). The THAD volume (cm3 ) was calculated by multiplying the total area of the enhancing lesions (traced on axial images) by the thickness of the scan (0.5-cm slices). We evaluated the sensitivity and specificity of the THAD volume and other computed tomography findings of AGC. The THAD volume was significantly larger in the AGC group than in the non-gangrenous acute cholecystitis group (P < 0.0001). The cutoff value of 78cm3 , determined using a receiver operating characteristics curve, yielded a sensitivity of 88.1% and specificity of 75.6% for detecting AGC. Multivariate analysis revealed a THAD volume of >78cm3 to be an independent predictor of AGC. Acute gangrenous cholecystitis can be diagnosed using THAD volume, resulting in improved treatment and fewer serious complications.

Dynamic CT angiography for therapy evaluation after transarterial chemoembolization of hepatocellular carcinoma.

Background Liver dynamic computed tomography (CT) is an established method for pre- and post-interventional evaluation of hepatocellular carcinoma. To date only the liver parenchyma and perfusion information of dynamic CT has been evaluated widely. Purpose To evaluate the vascular information contained in dynamic CT datasets. Material and Methods Dynamic CT performed one day after transarterial chemoembolization (60 mL of contrast medium, 6 mL/s, 40 s scan duration) were retrospectively evaluated. Conventional slice and angiographic maximum-intensity-projection reconstructions were calculated on a multi-modality post-processing platform. Datasets were evaluated for viable tumor, anatomy of the vasculature, and potential tumor-feeding vessels. The results were compared to digital subtraction angiography images. Results In total, 94 treated hepatocellular carcinoma nodules were evaluated (62 dynamic CT scans, 46 patients [34 men; mean age = 69 years]). Forty-six partially viable tumors were diagnosed after transarterial chemoembolization. In all of these, tumor-feeding vessels were found in dynamic CT. Seventeen suspected extra-hepatic tumor feeders were reported, of which 14 had not been found during previous transarterial chemoembolization. Conclusion Dynamic CT is useful in post-interventional imaging of hepatocellular carcinoma after transarterial chemoembolization due to its ability to detect residual viable tumor parts and to show previously unknown intra- and extra-hepatic tumor-feeding vessels.

Tracheobronchomalacia and Excessive Dynamic Airway Collapse: Medical and Surgical Treatment.

Excessive central airway collapse (ECAC) is characterized by excessive narrowing of the airway lumen during exhalation leading to dyspnea, cough, mucostasis, recurrent respiratory infections, and poor quality of life. Tracheobronchomalacia and excessive dynamic airway collapse are heterogeneous entities of ECAC and are characterized by a diverse nonspecific symptom profile. Although the pathophysiology of airway mechanics as well as morphology in both entities is different, current evidence so far shows no practical benefit in making such distinction since both have similar symptoms and the diagnostic and therapeutic work-ups are the same. The diagnosis of ECAC should be based on dynamic flexible bronchoscopy and/or dynamic computed tomography scan as well as clinical symptoms that are not fully explained by other lung diseases. Initial treatment of symptomatic ECAC includes treatment of coexisting conditions (such as chronic obstructive pulmonary disease, asthma, gastroesophageal reflux disease, and vocal cord dysfunction) and supportive treatment of dynamic central airway collapse (antibiotics for respiratory infections, aggressive therapy, pulmonary physiotherapy, pulmonary rehabilitation, and continuous positive airway pressure). A short-term stent trial in selected patients with severe symptomatic ECAC is needed to assess whether patients will have improvement in symptoms and thus identify patients who will benefit from surgical central airway stabilization. A multidisciplinary airway team in highly specialized centers with experience in the evaluation and treatment of this patient population is essential for optimal outcomes.

First series of minimally invasive, robot-assisted tracheobronchoplasty with mesh for severe tracheobronchomalacia

ObjectiveTracheobronchomalacia is a progressive, debilitating disease with limited treatment options. Open tracheobronchoplasty (TBP) is an accepted surgical option for management of severe tracheobronchomalacia. This study examined the outcomes of the first reported series of robot-assisted TBP (R-TBP). MethodsWe retrospectively reviewed the records of patients with clinical suspicion for tracheobronchomalacia who had dynamic computed tomography scan and subsequent R-TBP from May 2016 to December 2017. ResultsFour hundred thirty-five patients underwent dynamic computed tomography scan for suspicion of tracheobronchomalacia. Of this group, 42 patients underwent R-TBP. In the surgery group, the median age was 66 years (interquartile range, 39-72 years) and there were 30 women (71%). Respiratory comorbidities included asthma (88%) and chronic obstructive pulmonary disease (52%). The median operative time was 249 minutes (interquartile range, 266-277 minutes). Median hospital length of stay was 3 days (interquartile range, 2-4.75 days), and there were 19 postoperative complications (11 minor and 8 major). There were no mortalities at 90 days. Comparison of preoperative and postoperative pulmonary function testing demonstrated improvement in forced expiratory volume at 1 second by 13.5% (P = .01), forced vital capacity by 14.5% (P < .0001), and peak expiratory flow rate by 21.0% (P < .0001). Quality of life questionnaires also showed improvement with 82% reporting overall satisfaction with the procedure. ConclusionsR-TBP can be performed with low morbidity and mortality. Early follow-up reveals significant improvement in pulmonary function testing and high patient satisfaction when compared with preoperative baseline. Long-term follow-up is needed to demonstrate the durability of R-TBP and substantiate its role in the management of patients with symptomatic, severe tracheobronchomalacia.

Tracheobronchomalacia: An Unreported Pulmonary Complication of Acute Pancreatitis

Acute Pancreatitis(AP) is a common disease with a reported annual incidence ranging between 4.9 to 35 per 100,000 population. Multiple respiratory complications have been reported in AP including Acute Respiratory Distress Syndrome (ARDS). Here we present, to the best of our knowledge, the first reported case of Tracheobronchomalacia as a respiratory complication of AP.2900 Figure 1. CT scan showing tracheal diameter of 0.24 cm on expiration (A) and tracheal diameter of 2.9 cm on inspiration (B).A 54-year-old white male with history of Diabetes Mellitus, peripheral vascular disease (PVD) and no history of pulmonary disease was admitted for elective right Below-Knee Amputation(BKA) secondary to his PVD. Internal Medicine were asked to evaluate the patient for acute necrotizing pancreatitis (ANP) of undetermined etiology complicating his post-operative course. The patient was treated per protocol with hydration, Meropenem and pain management. Within one week of ANP onset, patient developed rapid respiratory distress. He was found to be in acute type II hypercapnic respiratory failure with PaO2/FiO2 <200. Chest radiography and arterial blood gase did not support the diagnosis of ARDS. Computed tomography (CT) with angiography ruled out pulmonary embolism but showed significant narrowing of the trachea on expiration with tracheal diameter less than 0.27 cm. When compared to a previous CT scan done 3 months earlier for a pulmonary nodule follow up, trahceal diameter was 2.8 cm. Diagnosis was confirmed by performing a dynamic CT scan with drop in tracheal diameter from 2.9 cm on inspiration to 0.24 cm on expiration (Image 1). The patient's respiratory status continued to deteriorate requiring endotracheal intubation and mechanical ventilation with weaning trials proving to be futile. The patient eventually developed Fungemia and expired after the patient's family opted for palliative extubation. Airway collapse related to Tracheobronchomalacia is an under-recognized diagnosis which should be suspected in patients with AP who develop acute respiratory distress in whom no specific etiology has been determined.