Sequential Computed Tomography Scans Research Articles

Comparison between ultrasonography and computed tomography for measuring skeletal muscle mass in critically ill patients with different body mass index

Among critical patients, there is an early onset of changes in both the quantity and quality of muscle mass. It is essential to find tools that promptly identify this muscle mass loss. The aim of this study was to compare the ultrasonography of the quadriceps femoris to the gold standard, thigh computed tomography (CT) for assessing the musculature of critically ill patients with different body mass index who have suffered traumatic brain injury. This is a prospective validation study in an Intensive Care Unit (ICU) specialized in trauma care, located at a tertiary teaching hospital. Our study involved a convenience sample of patients. Sequential ultrasound and CT scans were performed at three distinct time intervals: upon admission, between 24 and 96h' post-admission, and finally, between 96 and 168h' post-admission. For all ultrasound measurements, we conducted simultaneous quadriceps CT measurements. The correlation between measurements obtained by ultrasound and computed tomography at three different times and in three BMI ranges was analyzed, in individuals with normal weight, overweight and obese. Results: We analyzed 252 images in 49 patients in time 1, 40 patients in time 2, and 37 in time 3 to compare the thickness quadriceps muscle using US and CT. Of these, 18 patients had a BMI ≤ 24.9kg/m2 (normal weight), 18 patients from 25 to 29.9kg/m2 (overweight), and 8 patients had a BMI ≥ 30kg/m2 (obese). The mean age was 37 years, the majority (94%) were male and the main comorbidities were: hypertension 12%, diabetes 4% and 14% smoking. The results revealed minor discrepancies between measurements obtained through the two methods, these changes were not influenced by the body mass index, with these variations being practically insignificant in the context of clinical application. Thus, the correlation and concordance between the values obtained found a strong positive correlation with good limits of agreement. The Spearman's correlation coefficients obtained were r=0.89, 0.91 and 0.88, p<0.01at T1, T2 and T3 respectively for normal weight, r=0.91, 0.80 and 0.81, p<0.01at T1, T2 and T3 respectively for overweight and r=0.89, 0.94 and 0.84, p<0.01at T1, T2 and T3 respectively for obesity. In addition to a positive correlation, we observed a high agreement between the methods. The Bland & Altman analysis at time 1 showed, respectively, the bias of 1.46, 2.03 and 0.76. At time 2, the bias was 0.42, 3.11 and 2.12. At time 3, the bias was 2.26, 3.38 and 2.11mm. Our findings suggest that measure femoral quadriceps muscle thickness ultrasound-based exhibits a comparable performance to thigh CT. This conclusion stems from the excellent correlation and good agreement observed between ultrasound and CT, which is considered the gold standard for muscle assessment in critically ill patients. This clinical trial is registered at REBEC https://ensaiosclinicos.gov.br/ identifier: RBR-2bzspnz. The protocol was approved, on July 30, 2019, by the Research Ethics Committee of the Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto - Trial Registration Number: 3,475,851.

Correlation Between Optic Nerve Sheath Diameter at Initial Head CT and the Rotterdam CT Score.

Introduction Intracranial findings on imaging have long been used in assessing the severity of traumatic brain injury (TBI); the Rotterdam CT scoring (RCTS) is a more recent tool. Estimating the optic nerve sheath diameter (ONSD) at computed tomography (CT) can be another valuable predictor of the severity of the injury, especially as both ONSD and the RCTS are proven to be independent predictors of raised intracranial pressure (ICP).The study objective was to determine the correlation between ONSD at initial head CT and RCTS. Material and methods We observed 40 consecutive confirmed TBI cases at their initial head CT examinations in the emergency department for ONSD and the presence of other intracranial findings necessary to derive RCTS. The data were prospectively collected and analyzed, with statistical significance set at p ≤0.05 at 95% CI. Results The mean ONSD positively correlated with the Rotterdam CT score (r=0.368, p=0.019). A cut-off value of 6.83 mm was extrapolated from the receiver operator characteristic (ROC) curve as the mean binocular ONSD that best predicted severe RCTS (≥4) (sensitivity: 73.3%, specificity: 80%, positive predictive value: 68.7%, negative predictive value: 83.3%). The area under the curve (AUC) was 0.780 (p=0.003). Binary logistic regression analysis revealed an odd ratio (OR) of 11.000(95% CI: 2.438-49.627; p=0.002). Conclusion TBI patients with high RCTS have wide mean binocular ONSD. Those with average binocular ONSD above the cut-off value are likelier to have severe TBI. With the documented good correlation, ONSDmay become very useful in informing the clinical decision for sequential CT scans in TBI patients and, therefore, reducing the cumulative radiation burden from needless exposures. Furthermore, the non-invasive nature of its assessment will have more clinical relevance in resource-limited settings, where the skills and equipment for ICP monitoring are either not readily available or too expensive to be used routinely.

3D deformation and strain fields in drying kaolinite obtained from tracking internal bubbles using X-ray CT and ANN

AbstractDrying fine-grained sediments experience shrinkage and desiccation cracking that may dramatically alter their mechanical and hydraulic properties. This study adopts X-ray computed tomography (CT) to monitor the three-dimensional (3D) internal deformation and strain fields, and their relationships with desiccation crack formation, for drying kaolinite samples contained in plastic containers. Two kaolinite samples, one dried at room temperature and the other oven-dried at 60 °C, were CT scanned at several intervals during the drying process. From sequential CT scans for the same sample, entrained gas bubbles were extracted and used as tracking markers for deformation and strain field measurements. Since the bubble morphology continuously changed during the drying process, an artificial neural network (ANN) model was developed to link bubbles in sequential scans for the same sample. The tracking algorithm was trained with manually linked bubbles and optimised by comparing different combinations of bubble information, e.g. bubble location, size and shape. The drying samples experienced primarily vertical displacement before the air-entry value, while horizontal displacement occurred during vertical crack formation. Internal vertical and horizontal strains were generally uniform, indicating a limited impact of non-uniform sample drying and substrate constraint.

MP16-10 EFFECTS OF 24-HOUR URINARY CALCIUM OXALATE SUPERSATURATION LEVELS ON STONE GROWTH AND NEW STONE FORMATION: WHEN TO WORRY, WHEN TO NOT?

You have accessJournal of UrologyCME1 Apr 2023MP16-10 EFFECTS OF 24-HOUR URINARY CALCIUM OXALATE SUPERSATURATION LEVELS ON STONE GROWTH AND NEW STONE FORMATION: WHEN TO WORRY, WHEN TO NOT? Antonio R. H. Gorgen, Kalon L. Morgan, Andrei D. Cumpanas, Minh-Chau Vu, Jenny Liu, Seyed Amiryaghoub M. Lavasani, Kelvin Vo, Allen Rojhani, Zachary E. Tano, Sohrab N. Ali, Pengbo Jiang, Roshan M. Patel, Jaime Landman, and Ralph V. Clayman Antonio R. H. GorgenAntonio R. H. Gorgen More articles by this author , Kalon L. MorganKalon L. Morgan More articles by this author , Andrei D. CumpanasAndrei D. Cumpanas More articles by this author , Minh-Chau VuMinh-Chau Vu More articles by this author , Jenny LiuJenny Liu More articles by this author , Seyed Amiryaghoub M. LavasaniSeyed Amiryaghoub M. Lavasani More articles by this author , Kelvin VoKelvin Vo More articles by this author , Allen RojhaniAllen Rojhani More articles by this author , Zachary E. TanoZachary E. Tano More articles by this author , Sohrab N. AliSohrab N. Ali More articles by this author , Pengbo JiangPengbo Jiang More articles by this author , Roshan M. PatelRoshan M. Patel More articles by this author , Jaime LandmanJaime Landman More articles by this author , and Ralph V. ClaymanRalph V. Clayman More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003236.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Medical management for calcium oxalate (CaOx) urolithiasis commonly focuses on reducing CaOx supersaturation (SS). Using sequential computed tomography (CT) calculated 3D stone volume in conjunction with 24-hour CaOx SS levels, we sought to define CaOx SS thresholds for stable vs. increasing stone volume. METHODS: Thirty-four patients with a stone composition ≥50% CaOx and without interval stone passage or treatment, underwent 3D segmentation renal stone volume determinations based on two sequential CT scans a median of 406 days apart (range 98 to 2563 days) with at least 2 corresponding 24-hour urine analyses (i.e., Litholink™), obtained within 4 months of each CT scan. Increased stone volume was defined as ≥15% increase from baseline. T test and logistic regression were performed to evaluate CaOx SS levels among patients with and without a change in stone volume. RESULTS: An increase in stone volume occurred in 26 patients (76.5%); these individuals had a CaOx SS that was significantly higher for mean of baseline (SS 6.96 vs. 4.45), average (SS 6.79 vs. 4.12) and maximum (SS 9.20 vs. 5.45) (Figure 1); overall, there was a positive relationship between increase in CaOx SS and increased stone volume (p=0.043, p=0.014, p=0.024, respectively). The best predictor of an increase in stone volume was average CaOx SS (OR: 1.57, 95% CI 1.08 to 2.44). CONCLUSIONS: Among patients with CaOx kidney stones, 24-hour urine CaOx SS was positively associated with an increase in stone volume. CaOx SS below 3 appears favorable, whereas levels over 5 are concerning. Each additional point rise in average CaOx SS was associated with a three-fold higher risk of increased stone volume. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e206 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Antonio R. H. Gorgen More articles by this author Kalon L. Morgan More articles by this author Andrei D. Cumpanas More articles by this author Minh-Chau Vu More articles by this author Jenny Liu More articles by this author Seyed Amiryaghoub M. Lavasani More articles by this author Kelvin Vo More articles by this author Allen Rojhani More articles by this author Zachary E. Tano More articles by this author Sohrab N. Ali More articles by this author Pengbo Jiang More articles by this author Roshan M. Patel More articles by this author Jaime Landman More articles by this author Ralph V. Clayman More articles by this author Expand All Advertisement PDF downloadLoading ...

Sequential low-dose CT thorax scans to determine invasive pulmonary fungal infection incidence after allogeneic hematopoietic cell transplantation

Invasive fungal disease (IFD) during neutropenia goes along with a high mortality for patients after allogeneic hematopoietic cell transplantation (alloHCT). Low-dose computed tomography (CT) thorax shows good sensitivity for the diagnosis of IFD with low radiation exposure. The aim of our study was to evaluate sequential CT thorax scans at two time points as a new reliable method to detect IFD during neutropenia after alloHCT. We performed a retrospective single-center observational study in 265/354 screened patients admitted for alloHCT from June 2015 to August 2019. All were examined by a low-dose CT thorax scan at admission (CT t0) and after stable neutrophil recovery (CT t1) to determine the incidences of IFD. Furthermore, antifungal prophylaxis medications were recorded and cohorts were analyzed for statistical differences in IFD incidence using the sequential CT scans. In addition, IFD cases were classified according to EORTC 2008. At CT t0 in 9.6% of the patients, an IFD was detected and antifungal therapy initiated. The cumulative incidence of IFD in CT t1 in our department was 14%. The use of Aspergillus-effective prophylaxis through voriconazole or posaconazole decreased CT thorax t1 suggesting IFD is statistically significant compared to prophylaxis with fluconazole (5.6% asp-azol group vs 16.3% fluconazole group, p = 0.048). In 86%, CT t1 was negative for IFD. Low-dose sequential CT thorax scans are a valuable tool to detect pulmonary IFDs and guide antifungal prophylaxis and therapies. Furthermore, a negative CT t1 scan shows a benefit by allowing discontinuation of antifungal medication sparing patients from drug interactions and side effects.

Edema in critically ill patients leads to overestimation of skeletal muscle mass measurements using computed tomography scans

ObjectivesChanges in muscle mass and quality are important targets for nutritional intervention in critical illness. Effects of such interventions may be assessed using sequential computed tomography (CT) scans. However, fluid and lipid infiltration potentially affects muscle area measurements. The aim of this study was to evaluate changes in muscle mass and quality in critical illness with special emphasis on the influence of edema on this assessment. MethodsChanges in skeletal muscle area index (SMI) and radiation attenuation (RA) at the level of vertebra L3 were analyzed using sequential CT scans of 77 patients with abdominal sepsis. Additionally, the relation between these changes and disease severity using the maximum Sequential Organ Failure Assessment (SOFA) score and change in edema were studied. ResultsSMI declined on average 0.35%/d (±1.22%; P = 0.013). However, SMI increased in 41.6% of the study population. Increasing edema formation was significantly associated with increased SMI and with a higher SOFA score. Muscle RA decreased during critical illness, but was not significantly associated with changes in SMI or changes in edema. ConclusionIn critically ill patients, edema affects skeletal muscle area measurements, which leads to an overestimation of skeletal muscle area. A higher SOFA score was associated with edema formation. Because both edema and fat infiltration may affect muscle RA, the separate effects of these on muscle quality are difficult to distinguish. When using abdominal CT scans to changes in muscle mass and quality in critically ill patients, researchers must be aware and careful with the interpretation of the results.

Computed Tomography Thermography for Ablation Zone Prediction in Microwave Ablation and Cryoablation: Advantages and Challenges in an Ex Vivo Porcine Liver Model.

The aim of this study was to investigate the diagnostic accuracy of computed tomography (CT) for the prediction of ablation zones from microwave ablation (MWA) and cryoablation (CA) in an ex vivo porcine liver model. Sequential (30 seconds) CT scans were acquired during and after MWA and CA in an ex vivo porcine liver model. We generated 120-kVp equivalent reconstructions of generic dual-energy CT data sets, and comprehensive region-of-interest measurements were statistically correlated with invasive temperature monitoring using Pearson correlation coefficient. Binary logistic regression was performed for prediction of successful ablation. With the use of pooled data from 6 lesions in 2 separate experiments, correlation analysis of attenuation in Hounsfield units (HU) and temperature yielded r = -0.79 [confidence interval (CI), -0.85 to -0.71] for MWA and r = 0.62 (CI, 0.55 to 0.67) for CA.For MWA, there was a linear association between attenuation and temperature up to 75°C; thus, linear regression yielded a slope of -2.00 HU/°C (95% CI, -1.58 to -2.41). For CA, a linear association between attenuation and temperature was observed in the cooling phase with a slope of 2.11 HU/°C (95% CI, 1.79 to 2.58). In MWA treatment, binary logistic regression separated less than 70°C and greater than 70°C with 89.2% accuracy. Within the ice ball, temperatures above and below -20°C were distinguished with 65.3% accuracy. Our experiments reveal several difficulties in predicting ablation zone temperature from CT attenuation. Microwave ablation leads to gas production in the tissue, which degrades the accuracy of noninvasive temperature measurement, especially at higher temperatures. In CA, CT thermometry is limited by ice ball formation, which leads to homogeneous attenuation, nearly independent of temperature. Further research is needed to define the role of CT thermography in ablation zone monitoring in liver malignancies.

Computed Tomography-Guided Radiofrequency Thermocoagulation of the Gasserian Ganglion Using an Alternative to Hartel Anterior Approach: A Bicentral Study

Background: Trigeminal neuralgia (TN) is associated with multiple mechanisms involving peripheral and central nervous system pathologies. Among percutaneous treatments offered, radiofrequency thermocoagulation (RFT) is associated with longer duration of pain relief. Mostly due to anatomic variation, cannulation of the foramen ovale using the Hartel approach has a failure rate of 5.17%. Objectives: To report safety and efficacy of continuous RFT with an alternative to Hartel anterior approach under computed tomography (CT) guidance in patients with classic TN. Study Design: Retrospective institutional database review; bicentral study. Setting: Although this was a retrospective database research, institutional review board approval was obtained. Methods: Institutional database review identified 10 patients (men 8, women 2) who underwent CT-guided RFT of the Gasserian ganglion. Preoperational evaluation included physical examination and magnetic resonance imaging. Under anesthesiology control and local sterility measures, a radiofrequency needle was advanced, and its approach was evaluated with sequential CT scans. Motor and sensory electrostimulation tests evaluated correct electrode location. Pain prior, 1 week, 1, 3, and 6 months after were compared by means of a numeric visual scale (NVS) questionnaire. Results: Mean self-reported pain NVS score prior to RFT was 9.2 ± 0.919 units. One week after the RFT mean NVS score was 1.10 ± 1.287 units (pain reduction mean value of 8.1 units). At 3 and 6 months after thermocoagulation the mean NVS score was 2.80 ± 1.549 units and 2.90 ± 1.370 units, respectively. There were no postoperative complications. Three patients experienced facial numbness, which gradually resolved over a period of 1 month. Limitations: Retrospective nature; small number of patients; lack of a control group undergoing a different treatment of TN. Conclusions: Percutaneous CT-guided RFT of the Gasserian ganglion constitutes a safe and efficacious technique for the treatment of TN, with significant pain relief and minimal complication rates improving life quality in this group of patients. Key words: Trigeminal nerve, neuralgia, pain, radiofrequency, ablation, percutaneous, computed tomography, imaging

Ligamentous Lisfranc injuries: analysis of CT findings under weightbearing.

The aim of this study was to investigate the influence of different ligamentous Lisfranc injuries on computed tomography (CT) findings under weight-bearing and to emphasize the indications for surgical treatment of their various types. Sixteen human cadaveric lower limbs were placed in weight-bearing radiolucent frame for CT scanning. All intact specimens were initially scanned, and then, dorsal approach was used for sequential ligaments cutting of: (1) the dorsal and the interosseous (Lisfranc) ligaments between medical cuneiform (MC) and metatarsal 2 (MT2); (2) the plantar ligament between the MC and MT3; (3) the plantar ligament between MC and MT2. Based on sequential CT scans, the distances MT1-MT2, MC-T2, as well as the alignment and dorsal displacement of MT2 were measured. Slight increase in the distances MT1-MT2 and MC-MT2 was observed after the disruption of the dorsal and the interosseous ligaments. Further increase in MT1-MT2 and MC-MT2 distances was registered after the disruption of the ligament between MC and MT3. The largest distances MT1-MT2 and MC-MT2 were measured after the final plantar ligament cut between MC and MT2. Unequivocal instability is observed with simultaneous transection of the Lisfranc ligament with both plantar ligaments. On CT used as diagnostic tool, plantar injuries at the basis of the second and the third metatarsal are indirect signs of violation of the ligaments and represent an indication for surgical treatment. When using magnetic resonance imaging as diagnostic tool, a ruptured Lisfranc ligament alone without dislocation does not necessarily need surgical intervention.

Risk factors predictive of unfavorable distal aortic remodeling after surgical repair of type A thoracic aortic dissection.

One-third of the patients successfully treated for acute type A aortic dissection (AAD) require re-intervention secondary to the distal aortic disease progression. The aim of this study is to identify clinical and morphologic risk factors in the pre and postoperative AAD patients with respect to unfavorable aortic remodeling, reoperations and poor long term outcomes. One hundred and twenty-three consecutive patients who survived proximal AAD surgery were reviewed at a single institution. The medical charts and computed tomography (CT) studies of these patients were reviewed from 2005 to 2014. The short axis area of the true lumen (TL), false lumen (FL) and the total cross-sectional area were measured from reconstructed images using centerline technique at the largest segment each of the aortic arch (AA), descending thoracic aorta (TA), aorta proximal to the celiac artery (CA), and the abdominal aorta (AbA). Survival and time to first reoperation were analyzed with Kaplan Meier and Cox proportional-hazards models. Factors associated with radiologic change were evaluated using multiple linear regression models. A significant change was defined as >10% change (cm2) from the baseline CTA. At least one sequential CT scan was available for 62 (50%) of the 123 patients (40 male, 22 female; average age, 59.1±13.5 years). Mean interval (baseline and the comparison CT scan) was 779 days. In general, the TA and FL increased in size over the study period. Multivariate analysis showed that age >60 years and smoking were significantly associated with an increase in TL over time, while coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD) were associated with decrease TL (P=0.03). Hyperlipidemia and CAD were associated with an increase in FL size., while pre-existing aortic aneurysm, coronary surgery and hemodialysis were significant risk factors for reoperations (P=0.029). Age >60 (P=0.01), COPD (P=0.002), and male gender (P=0.02) were also associated with an increase in total area, signifying distal aneurysmal progression. Patient risk factors predict unfavorable long-term morphologic outcomes in the remaining aorta after AAD surgical repair. These factors can be used as markers to identify patients who may benefit from closer surveillance and possibly earlier endovascular intervention to the distal thoracic aorta.

Sequential 3-dimensional computed tomography analysis of implant position following total shoulder arthroplasty

Detection of postoperative component position and implant shift following total shoulder arthroplasty (TSA) can be challenging using routine imaging. The purpose of this study was to evaluate glenoid component position over time using 3-dimensional computed tomography (CT) analysis with minimum 2-year follow-up. Twenty patients underwent primary TSA with sequential CT scanning of the shoulder: a preoperative study, an immediate postoperative study within 2 weeks of surgery, and a postoperative study performed at minimum 2-year follow-up (CT3). Postoperative glenoid component position and central peg osteolysis were assessed across the immediate postoperative CT scan and CT3. Glenoids with evidence of component shift and/or grade 1 central peg osteolysis on CT3 were considered at risk of loosening. Of the patients, 7 (35%) showed evidence of glenoid components at risk of loosening on CT3, 6 with component shift (3 with increased inclination alone, 1 with increased retroversion alone, and 2 with both increased inclination and retroversion). Significantly more patients with glenoid component shift had grade 1 central peg osteolysis on CT3 compared with those without shift (83% vs 7%, P = .002). One clinical failure occurred, with the patient undergoing revision to reverse TSA for rotator cuff deficiency. Three-dimensional CT imaging analysis following TSA identified changes in glenoid component position over time, with inclination being the most common direction of shift and grade 1 central peg osteolysis commonly associated with shift. These findings raise concern for glenoids at risk of loosening, but further follow-up is needed to determine the long-term clinical impact of these findings.

Tyrosine kinase inhibitors rechallenge in solid tumors: a review of literature and a case description with lenvatinib in thyroid cancer

ABSTRACTIntroduction: In the last decade tyrosine kinase inhibitors (TKIs) have been employed for a wide range of hematological and solid tumors and today they represent a valid therapeutic option for different neoplasms. Among them, both sorafenib and lenvatinib were approved for the treatment of radioactive iodine (RAI) refractory differentiated thyroid carcinoma (DTC). Unfortunately, in some cases the efficacy of TKIs is limited by the onset of drug resistance after the initial response.Areas covered: We report the case of a patient with a RAI refractory advanced DTC, treated with lenvatinib after surgery, multiple RAI administrations, traditional chemotherapy, and sorafenib. During treatment with lenvatinib, a noticeable response was detected by sequential computed tomography scans but, after 27 months, tumor progression became evident and led to lenvatinib interruption. In absence of any active treatment, a further disease progression was documented, and lenvatinib was re-administered obtaining a new objective response. Starting from this case report, we review available reports about the rechallenge with TKIs in solid tumors, discussing the possible mechanisms underlying the efficacy of this approach.Expert commentary: Rechallenge with TKIs in solid tumors could be a therapeutic option in subjects with advanced and metastatic DTC who experience a progressive disease after initial response to lenvatinib.

Infected Abdominal Aortic Aneurysms Treated with Extra-anatomic Prosthesis Bypass in the Retroperitoneum

Infected abdominal aortic aneurysms (iAAAs) are rare but life-threatening diseases. The purpose of the present study was to report our experience of extra-anatomic prosthesis bypass in the retroperitoneum as a treatment for iAAAs. Data of 8 consecutive patients diagnosed with iAAAs and treated by an extra-anatomic prosthesis bypass in the retroperitoneum were retrospectively collected. Operative details were as follows: one side of the retroperitoneal space was selected to build a track, and a bifurcated expanded polytetrafluoroethylene prosthesis was placed through the track. The proximal end of the prosthesis was sutured with the normal segment of abdominal aorta proximal to the infected aneurysm by end-to-end anostomosis. The 2 distal ends of the prosthesis were, respectively, sutured with the external iliac artery distal to the aneurysm. The anastomoses were then consolidated with the nearby connective tissue. After the closure of the retroperitoneum, the infected aneurysm was incised, and the infected tissue was debrided. Drainage tubes were placed in the aneurysm sac, which was packed with an omentum flap. All patients received perioperative antibiotic therapy for a period of time. All 8 patients were regularly followed up by outpatient observation. Eight patients with iAAAs underwent an extra-anatomic prosthesis bypass in the retroperitoneum and debridement of the infected aneurysm. An emergency operation was performed for 1 patient who underwent concomitant gastrointestinal procedures for aortoduodenal fistula. All 8 patients were definitively diagnosed by one or more sequential computed tomography scans combined with other methods. The blood or tissue cultures of all cases were positive in the perioperative period, with Salmonella (5 cases) being the most common pathogens. Other pathogens included Burkholderia pseudomallei (2 cases) and Escherichia coli (1 case). All patients survived and were discharged in 4-5weeks after their operations. All patients were free from graft infection during the follow-up period. The extra-anatomic prosthesis bypass in the retroperitoneum for treating iAAAs was safe and effective. Our experience with the procedure may provide a new approach for the treatment of this disease.

VESS29. Impact of Proximal Seal Zone Length and Intramural Hematoma on Clinical Outcomes and Aortic Remodeling Following Thoracic Endovascular Aortic Repair for Aortic Dissections

Thoracic endovascular aortic repair (TEVAR) has become the treatment of choice for aortic dissections in many centers. While adequate proximal seal is a fundamental requisite for TEVAR, there are insufficient data on the impact of the proximal seal length on patient outcomes. The goal of this study was to describe the proximal seal zone achieved during TEVAR for aortic dissections as well as its effect on clinical outcomes and aortic remodeling. A retrospective review was performed on all patients who underwent TEVAR for aortic dissections at a single institution from 2006 to 2016. Preoperative computed tomography (CT) was used to identify the entry tear, extent of dissection, and distances between the arch branches in three-dimensional centerline. Proximal seal zone length was calculated on postoperative imaging. Sequential postoperative CT scans were analyzed for remodeling of the true and false lumen aortic diameters over time. Clinical outcomes, including retrograde type A dissection (RTAD), death, and aortic reinterventions, were recorded. During the study period, 84 patients underwent TEVAR for aortic dissections. Indications for TEVAR were malperfusion (n = 12), aneurysm (n = 26), persistent pain (n = 33), rupture (n = 8), uncontrolled hypertension (n = 2), and other (n = 3). Mean follow-up was 14 months (range, 0-94 months). In 28 patients (33%), the aorta proximal to stent graft was without intramural hematoma, while the proximal seal zone in 56 patients (67%) was entirely in intramural hematoma. Proximal seal according to the manufacturers’ instructions for use (2 cm of normal aorta) was achieved in only six patients (7.1%). Thirty-nine patients (46%) would have required total arch debranching to obtain a 2-cm proximal seal. After TEVAR deployment in intramural hematoma, two RTADs underwent operative repair, and one patient had a sudden death. No RTADs occurred after TEVAR deployment in nondissected aorta without intramural hematoma. Overall reintervention-free survival was 52% at 24 months. Mean expansion of thoracic true lumen diameters were 151%, 177%, 191%, 202%, and 211% of baseline at the 1-, 6-, 12-, 24-, and 36-month follow-up, respectively. Regression of thoracic false lumen diameters was seen in 87%, 83%, 73%, 71%, and 70% at the 1-, 6-,12-, 24-, and 36-month follow-up. Complete thoracic false lumen thrombosis was seen in 55%. Aortic remodeling, such as false lumen thrombosis, true lumen expansion, and false lumen regression, was not different between the patients who had a proximal landing zone in the intramural hematoma and those who did not. Achieving a 2-cm proximal seal zone in TEVAR for aortic dissections often requires extensive arch debranching. Stent graft deployment with shorter than a 2-cm proximal seal zone in a normal aorta without intramural hematoma avoids RTAD, and induces aortic remodeling.

Healing Process of Osteonecrotic Lesions of the Femoral Head Following Transtrochanteric Rotational Osteotomy: A Computed Tomography-Based Study.

BackgroundTranstrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT).MethodsAmong 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans.ResultsPlain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p = 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p = 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area.ConclusionsThe majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.

Suppression of the CT Beam Hardening Streak Artifact Using Predictive Correction on Detector Data

The purpose of the research was to develop an automated program incorporating a predictive artifact correction technique (PACT) to correct for the signal deviations from metal beam hardening artifacts in Computed Tomography (CT) detector raw data. Thin-slice sequential CT scans were performed on a dosimetry head phantom using a Somatom Sensation 16 scanner to establish a ground truth image. Metal pins were then affixed to either side of the phantom at the three and nine o’clock positions to cause streak artifact in detector raw data and a subsequent streak image. The program automatically detected the extent of the overlap peaks in the detector raw data causing the artifact. It profiled a correction using adjacent projections so that the peak error could be corrected rather than simply being removed or smoothed by interpolation. The PACT algorithm modified raw data was then reconstructed on a SYNGO CT reconstruction workstation. This image was then compared against ground truth and that produced by commercially available metal artifact reduction projection completion and also a research based iterative technique. Qualitative results illustrate superior suppression of streak artifact in images using PACT when compared directly to tested projection completion methods but inferior to iterative reconstruction. Recovery of voxel data underlying the streak is also demonstrated to be quantitatively superior with PACT when referenced to the original ground truth image. Limitations were however detected with the threshold technique for initial localisation of the streak sources. The work still demonstrates the feasibility of this predictive artifact correction technique in correcting beam hardening affected voxel data without recourse to expensive additional options such as iterative reconstruction or dual energy that are not so commonly available in the clinical setting.

The Role of Neoadjuvant Therapy in Characterizing Indeterminate Lung Lesions in Patients with Resectable Colorectal Liver Metastases.

Incidental pulmonary lesions are frequently found during the preoperative evaluation of patients considered for resection of colorectal liver metastases (CRLM), and their presence can confound management decisions. This study investigates the role of clinical and radiologic factors, including response to preoperative systemic chemotherapy, in determining the malignant probability of these lesions. Computed tomography (CT) scans of 33 patients with small (≤1 cm) lung lesions undergoing resection for CRLM after preoperative chemotherapy were reviewed. Radiological features were recorded from three sequential CT scans (baseline, postchemotherapy, and follow-up). Malignancy was diagnosed either by resection or serial imaging. Chemotherapy response comparing lung lesions and CRLM was categorized as: (1) concordant or (2) discordant. Chemotherapy response, imaging features, and other clinical factors were evaluated in multivariate analyses as predictors of malignancy. Among the 86 indeterminate lung lesions identified, 23 % (20/86) were found to be metastases on follow-up. Lesions 6-10 mm were more likely to be metastases (odds ratio [OR] = 3.14, p = 0.045), as were lesions located in the lower lobes (OR = 4.50, p = 0.018). Concordant chemotherapy response was found in 13 of 86 (15 %) and was independently associated with metastatic disease (OR = 19.87, p < 0.001), with 11 of 13 (85 %) lesions determined to be metastases. In contrast, only 9 of 73 lesions (12 %) with discordant response were found to be metastases. Lesion size, location, and chemotherapy response pattern were independent predictors of malignancy for patients with resectable CRLM and small indeterminate lung lesions. Utilization of preoperative chemotherapy can be a useful method of ruling out pulmonary metastases in these patients.

Retrograde venous bullet embolism after thoracic gunshot

Bullet embolism is a rare complication of penetrating gunshots. We present a case of a 24-year-old man with a gunshot wound in the left scapular area, with no exit wound. Abdominal X-rays and a computed tomography (CT) scan suggested that the bullet was located within the intra-abdominal topography (intrahepatic), but laparotomy revealed no intra-abdominal injuries. After surgery, a sequential CT scan showed that the bullet had migrated to the right internal iliac vein (IIV). Venography confirmed the diagnosis of right IIV embolism and the decision was taken to attempt snare retrieval of the bullet, which was unsuccessful. It was therefore decided to leave the missile impacted inside the right IIV and the patient was put on oral anticoagulation. The patient recovered and was event free at 6 months' follow up.

Establishment of the craniofacial three-dimensional finite element models with the sutures defined alone

To develop a child craniofacial three-dimensional (3D) finite element model (FEM) with sutures defined alone. The CT data for this study was developed from sequential computed tomography scan images taken at 0.625 mm intervals of an 8 years children skull. Data set was imported into Mimics 10.0 and processed with Geomagic 9.0, and exported as initial graphics exchange specification(IGES) files. The IGES files were then imported into Ansys 13.0 to set up two FEM with or without the median palatine suture being opened. The FEM contained nine craniofacial sutures and eight teeth which were defined alone.For simulating orthopedic maxillary protraction, three forces (F1-F2) were loaded on FEM.F1(1 N) was loaded at 1 cm above the geison. F2(1 N) was loaded at articular fossa of temporal bone. F3(2 N) was directed anteriorly and paralleled with occlusal plane near the canine. The stress distribution and the values distributed in each point gained in the two models were compared. Two craniofacial 3D FEM of the child were developed with the median palatine suture opened or not .With median palatine suture being opened or not, the two models showed the similar von Mises stresses (VMS). The distribution of the VMS was in the bridge of the nose and dextro-ala nasi.When the median palatine suture was opened, the max VMS value was 18916.00×10(-4) MPa which appeared in the nose point and the min VMS value was 1.61×10(-4) MPa which appeared in the maxillary central incisor point. At the same time, the max stress value at the direction Y was -3985.30×10(-4) MPa and appeared in the frontomaxillary suture point, and the min Y value was 0.08×10(-4) MPa which appeared in the maxillary central incisor point. When the median palatine suture was not opened, the max VMS value was 19 244.00×10(-4) MPa and appeared in the nose point. The min VMS value was 1.62×10(-4) MPa and appeared in the maxillary central incisor point. At the same time, the max stress value at the direction Y was -4258.20×10(-4) MPa and appeared in the frontomaxillary suture point, and the min Y value was 0.08×10(-4) MPa which appeared in the maxillary central incisor point. To define the sutures as entities alone contributed to develop child craniofacial 3D FEM which consist nine sutures. There was tiny difference in stress distribution in both the VMS and in Y direction with the median palatine suture being opened or not.

Complete gallbladder torsion diagnosed with sequential computed tomography scans: a case report

IntroductionTorsion of the gallbladder is an extremely rare cause of acute abdomen, which commonly affects thin elderly women. A prompt surgical approach is necessary to avoid fatal complications associated with gangrene and perforation of the gallbladder. However, it is difficult to make a preoperative diagnosis using ordinary imaging modalities.Case presentationAn 84-year-old Japanese woman was admitted to our hospital due to left lower abdominal pain. Her pain shifted suddenly to the right upper abdomen a half day after admission. Although her enlarged and wall-thickened gallbladder had been already seen at admission, it rotated approximately 180 degrees and deviated to the midline of her abdomen on the second computed tomography scan, which helped us to make a correct diagnosis of gallbladder torsion. The patient underwent an emergency operation (detorsion and cholecystectomy) and recovered without any complications. The gallbladder had necrosis due to torsion.ConclusionSequential diagnostic imaging might be helpful to make a preoperative diagnosis of gallbladder torsion when the gallbladder is enlarged and wall thickened but the patient does not present with typical clinical symptoms.