Computed Tomographic Osteolytic Analysis of a First-Generation Remelted Highly Cross-Linked Polyethylene in Total Hip Arthroplasty—At a Minimum of 15-Year Follow-Up

BackgroundLow polyethylene wear rate and low incidence of osteolysis have been reported after total hip arthroplasty (THA) using first-generation remelted highly cross-linked polyethylene (HXLPE). However, osteolysis has not been evaluated in long-term studies of these patients (15 years or more). The present study assessed computed tomography (CT) images to determine the incidence of osteolysis associated with HXLPE in THA during at least 15 years of follow-up.MethodsWe evaluated 105 primary THAs in 84 patients (77 women and 7 men). Mean follow-up was 15.9 years (range, 15-18 years). All THAs used a Longevity HXLPE liner and a 26-mm zirconia femoral head. Areas of osteolysis were identified from CT images using 3D and multiplanar reconstruction views.ResultsCT 3D multiplanar reconstruction images at 15-year follow-up showed no obvious osteolysis in the acetabulum or femur of any patient. No patients developed cup loosening or liner breakage.ConclusionOur study indicates that first-generation remelted HXLPE liners do not increase the risk of osteolysis during 15-year follow-up and suggests that the wear particles from first-generation remelted HXLPE are less biologically active than those generated by conventional polyethylene devices.     

Prospective nonrandomized study to evaluate cone beam computed tomography for technical assessment of standard and complex endovascular aortic repair

ObjectiveThe objective of this study was to analyze the utility of cone beam computed tomography (CBCT) for technical assessment of standard and complex endovascular aneurysm repair (EVAR).MethodsData of consecutive patients who underwent standard or complex EVAR in 2016 and 2017 at our institution were entered into a prospective database and analyzed retrospectively. There were 154 patients (126 male; mean age, 74 ± 8 years) enrolled in a prospective study between 2016 and 2017. A total of 170 aortic procedures were investigated, including 85 fenestrated-branched EVARs (F-BEVARs), 42 abdominal and thoracic EVARs, 32 EVARs with iliac branch devices, and 11 aorta-related interventions. Technical assessment was done using CBCT with and without contrast enhancement, digital subtraction angiography (DSA), and computed tomography angiography (CTA). Patients with stage 3B or stage 4 chronic kidney disease had CBCT without contrast enhancement. Radiation exposure (mean dose-area product), effective dose (ED), and amount of iodine contrast agent were analyzed. End points were presence of any endoleak, positive findings warranting possible intervention (stent kink or compression, type I or type III endoleak, dissection, thrombus), and need for secondary intervention.ResultsRadiation exposure and amount of iodine contrast agent were significantly higher (P < .05) for F-BEVAR compared with other aortic procedures (174±101 Gy∙cm² vs 1135±113 Gy∙cm² and 144±60 mL vs 122±49 mL). ED averaged 74±36 mSv for the aortic procedure, 18 ± 18 mSv for fluoroscopy, 7 ± 7 mSv for DSA acquisition, 15±7 mSv for CBCT, and 34±17 mSv for CTA imaging (P < .001). Endoleak detection was significantly higher (P < .001) with CBCT (53%) compared with DSA (14%) and CTA (46%). CBCT identified 52 positive findings in 43 patients (28%), higher for F-BEVAR compared with other aortic procedures (35% vs 16%; P = .01). Positive findings included stent compression or kink in 29 patients (17%), type I or type III endoleak in 16 patients (10%), and arterial dissection or thrombus in 7 patients (5%). Of these, 28 patients (18%) had positive findings that prompted an intraoperative (17%) or delayed intervention (1%). Another 15 patients (10%) with minor positive findings were observed with no clinical consequence. DSA alone would not have detected positive findings in 34 of 43 patients (79%), including 21 patients (49%) who needed secondary interventions. CTA diagnosed two (1%) additional endoleaks requiring intervention (one type IC, one type IIIC) that were not diagnosed by CBCT. Replacing DSA and CTA by CBCT would have resulted in 53% ± 13% reduction in amount of iodine contrast agent and 55% ± 12% reduction in ED (P < .05).ConclusionsCBCT reliably detected positive findings prompting immediate revisions in nearly one of five patients, with the highest rates among F-BEVAR patients. Detection of any endoleak was higher with CBCT compared with DSA or CTA, but most endoleaks were observed. DSA alone failed to detect positive findings warranting revisions.     

Dual contrast in computed tomography allows earlier characterization of articular cartilage over single contrast

Cationic computed tomography contrast agents are more sensitive for detecting cartilage degeneration than anionic or non-ionic agents. However, osteoarthritis-related loss of proteoglycans and increase in water content contrarily affect the diffusion of cationic contrast agents, limiting their sensitivity. The quantitative dual-energy computed tomography technique allows the simultaneous determination of the partitions of iodine-based cationic (CA4+) and gadolinium-based non-ionic (gadoteridol) agents in cartilage at diffusion equilibrium. Normalizing the cationic agent partition at diffusion equilibrium with that of the non-ionic agent improves diagnostic sensitivity. We hypothesize that this sensitivity improvement is also prominent during early diffusion time points and that the technique is applicable during contrast agent diffusion. To investigate the validity of this hypothesis, osteochondral plugs (d = 8 mm, N = 33), extracted from human cadaver (n = 4) knee joints, were immersed in a contrast agent bath (a mixture of CA4+ and gadoteridol) and imaged using the technique at multiple time points until diffusion equilibrium. Biomechanical testing and histological analysis were conducted for reference. Quantitative dual-energy computed tomography technique enabled earlier determination of cartilage proteoglycan content over single contrast. The correlation coefficient between human articular cartilage proteoglycan content and CA4+ partition increased with the contrast agent diffusion time. Gadoteridol normalized CA4+ partition correlated significantly (P < .05) with Mankin score at all time points and with proteoglycan content after 4 hours. The technique is applicable during diffusion, and normalization with gadoteridol partition improves the sensitivity of the CA4+ contrast agent.     

Reduction of patient radiation dose with a new organ based dose modulation technique for thoraco-abdominopelvic computed tomography (CT) (Liver dose right index)

Purpose

To evaluate the radiation dose reduction, image quality and diagnostic confidence with thoraco-abdominopelvic computed tomography (TACT) using a new organ based dose modulation system (liver dose right index [Liver DRI]), compared to TACT using a standard automatic exposure control adjusting mA according to attenuation.

Accuracy of cone-beam computed tomography for syndesmosis injury diagnosis compared to conventional computed tomography

BackgroundSyndesmosis injury can lead to ankle mortise instability and early osteoarthritis. Several multiple detector computed tomography (MDCT) methods for measurement have been developed. Weight-bearing cone beam CT (WB CBCT) is an emerging technique that offers the possibility of upright-position scanning and lower doses. This study sought to assess the diagnostic accuracy of WB CBCT in syndesmose injury compared to MDCT, with instability confirmed via manual testing upon arthroscopic examination.MethodsThree musculoskeletal radiologists with different levels of expertise prospectively analyzed 11 MDCT and eight WB CBCT scans of the same trauma-afflicted ankles with clinical suspicion of syndesmosis lesion over a period of 5 months. They evaluated 10 methods of measurement in both sides. Syndesmosis was considered pathological on arthroscopic examination in four patients. Correlation between readers was evaluated with intra-class correlation testing (p < 0.05 was considered significant). Capacity of discrimination was assessed by area under the curve (AUC) for all methods.ResultsInter-observer agreement was near excellent for both WB CBCT and MDCT for the anterior tibio-fibular (TF) distance (ICC = 0.781 and 0.831, respectively), posterior TF distance (ICC = 0.841 and 0.826), minimal TF distance (ICC = 0.899 and 0.875), and TF surface (ICC = 0.93 and 0.84). AUC were better for MDCT than WB CBCT in assessing syndesmosis instability for: anterior TF distance (ROC = 0.869 vs. 0.555, p = 0.01), minimal TF distance (ROC = 0.883 vs. 0.608, p = 0.02) and antero-posterior fibular translation (ROC = 0.894 vs. 0.467, p = 0.006).ConclusionsMDCT demonstrated better ability to distinguish pathological syndesmosis than WB CBCT, with the antero-posterior fibular translation the best discriminating measurement. The physiological widening of the contralateral syndesmosis occurring with the WB CBCT upright position may explain these results.     

Annotated normal CT data of the abdomen for deep learning: Challenges and strategies for implementation

PurposeThe purpose of this study was to report procedures developed to annotate abdominal computed tomography (CT) images from subjects without pancreatic disease that will be used as the input for deep convolutional neural networks (DNN) for development of deep learning algorithms for automatic recognition of a normal pancreas.Materials and methodsDual-phase contrast-enhanced volumetric CT acquired from 2005 to 2009 from potential kidney donors were retrospectively assessed. Four trained human annotators manually and sequentially annotated 22 structures in each datasets, then expert radiologists confirmed the annotation. For efficient annotation and data management, a commercial software package that supports three-dimensional segmentation was used.ResultsA total of 1150 dual-phase CT datasets from 575 subjects were annotated. There were 229 men and 346 women (mean age: 45 ± 12 years; range: 18–79 years). The mean intra-observer intra-subject dual-phase CT volume difference of all annotated structures was 4.27 mL (7.65%). The deep network prediction for multi-organ segmentation showed high fidelity with 89.4% and 1.29 mm in terms of mean Dice similarity coefficients and mean surface distances, respectively.ConclusionsA reliable data collection/annotation process for abdominal structures was developed. This process can be used to generate large datasets appropriate for deep learning.