Underwent Computed Tomography Angiography Research Articles

Deep-learning reconstruction enhances image quality of Adamkiewicz Artery in low-keV dual-energy CT.

Low-keV virtual monoenergetic images (VMIs) of dual-energy computed tomography (CT) enhances iodine contrast for detecting small arteries like the Adamkiewicz artery (AKA), but image noise can be problematic. Deep-learning image reconstruction (DLIR) effectively reduces noise without sacrificing image quality. To evaluate whether DLIR on low-keV VMIs of dual-energy CT scans improves the visualization of the AKA. We enrolled 29 patients who underwent CT angiography before aortic repair. VMIs obtained at 70 and 40 keV were reconstructed using hybrid iterative reconstruction (HIR), and 40 keV VMIs were reconstructed using DLIR. The image noise of the spinal cord, the maximum CT values of the anterior spinal artery (ASA), and the contrast-to-noise ratio (CNR) of the ASA were compared. The overall image quality and the delineation of the AKA were evaluated on a 4-point score (1 = poor, 4 = excellent). The mean image noise of the spinal cord was significantly lower on 40-keV DLIR than on 40-keV HIR scans; they were significantly higher than on 70-keV HIR images. The CNR of the ASA was highest on the 40-keV DLIR images among the three reconstruction images. The mean image quality scores for 40-keV DLIR and 70-keV HIR scans were comparable, and higher than of 40-keV HIR images. The mean delineation scores for 40-keV HIR and 40-keV DLIR scans were significantly higher than for 70-keV HIR images. Visualization of the AKA was significantly better on low-keV VMIs subjected to DLIR than conventional HIR images.

Individual Bilateral Difference of Femur, Tibia, and Leg Rotation: A Clinical Study of 141 Healthy Japanese Individuals Using Computed Tomography.

Background The malrotation of a femur and tibial fracture after surgery has been described in many articles. However, these studies have not considered individual bilateral differences (IBDs). The IBD of femur and tibial rotation has been identified via computed tomography (CT) in recent American studies. The IBD in rotation should be considered during femur and tibial surgery. However, IBDs in femur and tibial rotation remain unknown in the Japanese population. This study aimed to evaluate the rotation of the femur, knee, tibia, and leg, sex differences, and IBD in rotation among Japanese individuals with healthy bones by using CT analysis. Materials and methods In total,141 patients who underwent CT angiography or venography were included (70 men, 71 women; mean age, 44.7 years). The bilateral axial femur, knee, tibia, and leg rotation alignment were independently measured. The distribution, sex, and IBD were analyzed. The IBD in rotation had two statistical factors: absolute bilateral difference (ABD) and relative bilateral difference (RBD). Results The mean ABD of femur rotation was 6.5°, and the distribution of ABD of femur rotation ≤15° was 95%. The mean ABD of tibia rotation was 5.1°, and the distribution of ABD of tibia rotation ≤10° was 89%. The RBD of femur rotation was not significantly different between the right and left sides. The RBD of tibia rotation showed a higher mean external rotation of 3.3° on the right side (<0.001). The Pearson correlation coefficients of the femur, knee, tibia, and leg rotation between the right and left sides were high (r= 0.702-0.81; all, p<0.001). All elements of rotation showed significant differencesbetween men and women,whereasthe ABD and RBD of all elements showed no significant difference. Conclusion The distributions of ABD in femur and tibia rotation supported the previous definition of an acceptable rotation difference between the normal and fractured femur and tibia of ≤15°and ≤10°, respectively. The possibility of higher external rotation on the right side needs to be taken into account during tibial surgery.

Evaluation of the mesenteric arterial vasculature by computed tomography angiography and its implications for colorectal cancer surgery.

To determine the branching patterns of the inferior mesenteric artery (IMA) and to describe the clinical applicability of computed tomography (CT) angiography in the evaluation of these vessels to facilitate the planning of colorectal cancer surgery. We included 100 patients who underwent CT angiography of the abdomen and pelvis. The branching patterns of the IMA were examined and classified as type 1 (bifurcated), including 1A (sigmoid and left colic arteries arising from a common trunk), 1B (sigmoid and superior rectal arteries arising from a common trunk) and 1C (sigmoid arteries arising from both trunks); type 2 (trifurcated); and type 3 (no left colic branch). Among the 100 patients evaluated, we found the variant to be type 1A in 9%, type 1B in 47%, type 1C in 24%, type 2 in 16%, and type 3 in 4%. Preoperative CT angiography for evaluating the IMA branching pattern could inform decisions regarding the surgical approach to colorectal cancer.

Association Between Perivascular Adipose Tissue Density and Atherosclerosis in the Descending Thoracic Aorta.

Radiodensity measured by computed tomography (CT) in Hounsfield Units (HU) is emerging as a clinical tool for detecting perivascular adipose tissue (PVAT) inflammation. In the present study, we hypothesized that PVAT radiodensity might predict the risk of descending thoracic aorta atherosclerosis. A total of 73 subjects who underwent CT angiography to investigate aortic disease were retrospectively analyzed. PVAT radiodensity, aortic complex plaque (ACP), mean plaque-burden score (MPBS), and plaque density were measured, and the association between them was analyzed. Perivascular adipose tissue radiodensity (HU) in patients with different aortic plaques grades (grade 1, 2, 3, and 4) were -93.71 ± 2.50, -93.63 ± 3.93, -90.24 ± 4.49, and -89.90 ± 5.18, respectively, and the difference was significant (P = .010). In the regression analysis, PVAT radiodensity was an independent predictor of ACP, with an OR of 1.263. In the linear analysis, PVAT radiodensity was an independent predictor of MPBS, with a β-coefficient of .073. In the univariate analysis, only the PVAT radiodensity was significantly associated with plaque density, with a β-coefficient of -1.666. In conclusion, PVAT density was independently related to descending thoracic aorta atherosclerosis.

Effects of left ventricular mass index on computed tomography derived fractional flow reserve in significant obstructive coronary artery disease

Abstract Background In significant obstructive coronary artery disease (SOCAD), a mismatched assessment of the severity of coronary artery stenosis may occur between invasive coronary angiography and computed tomography (CT) derived fractional flow reserve (FFRCT). The exact mechanisms of unexpected underestimation of FFRCT remain unknown. Purpose The aims of this study are (1) to clarify the mechanisms of underestimation on FFRCT; and (2) to identify the predictive factors of FFRCT underestimation above the value of 0.80 in SOCAD vessels. Methods A total of 1160 outpatients who underwent CT angiography (CTA) with FFRCT analysis for suspected coronary artery disease (CAD) between January 2017 and June 2020 were evaluated. Among them, 141 consecutive patients who had both CTA coupled to FFRCT analysis and invasive angiogram showing &amp;gt;75% coronary stenosis were included for analysis. Vessels were divided into two groups according to FFRCT at the distal vessel: FFRCT &amp;gt;0.80 (n=12) and FFRCT ≤0.80 (n=153). Vessel-related parameters, including vessel morphology (vessel length and lumen volume) and plaque components (non-calcified plaque volume and calcified plaque volume) and left ventricular (LV) myocardial-related parameters, including LV wall thickness at each site of the myocardium, and LV mass were evaluated semi-automatically. Results Vessel morphology and plaque components did not differ between FFRCT &amp;gt;0.80 and ≤0.80, whereas LV wall thickness (average; 10.7±2.7 vs. 8.4±1.6 mm, and maximal; 13.5±3.0 vs. 10.6±1.8 mm, all p value &amp;lt;0.001), LV mass (136.4±38.4 vs. 98.8±26.8 g, p&amp;lt;0.001), and LV mass index (73.8±22.6 vs. 51.8±12.2 g/m2, p&amp;lt;0.001) were significantly higher in FFRCT &amp;gt;0.80. Next, we investigated the parameters that correlated with FFRCT. Of all, vessel morphology and plaque components were not related to FFRCT, whereas maximal LV wall thickness, r=0.24, p=0.01; LV mass, r=0.19. p=0.04; and LV mass index, r=0.30, p=0.001) correlated with FFRCT. In the vessels showing FFRCT &amp;gt;0.80, only LV mass (r=0.84, p=0.005) and LV mass index (r=0.67, p=0.047) correlated with FFRCT. (Figure 1). LV mass index was the strongest predictor of a distal FFRCT of &amp;gt;0.80 with the area under curve (AUC) 0.81, 95% CI 0.62 – 1.00, P&amp;lt;0.0001 and an optimal cut-off value of 66.5 g/m2 sensitivity 77.8%, specificity 89.6% (Figure 2). Conclusions FFRCT is affected not by vessel-related parameters but LV myocardial-related parameters in SOCAD. The presence of an excessive LV mass is a major predictor of underestimation of FFRCT in SOCAD vessels. LV myocardial-related parameters should be considered when interpreting numerical values of FFRCT to avoid the possibility of overlooked SOCAD. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2

Impact of vascular morphology and plaque characteristics on computed tomography derived fractional flow reserve in early stage coronary artery disease

Abstract Background FFRCT gradually decreases from the proximal to the distal part of a vessel and reach the pathological threshold for significant ischemia even in the absence of obstructive coronary artery disease (CAD). The exact mechanisms of such gradual FFRCT decline remain unknown. Purpose The aims of this study are (1) to clarify the mechanisms of the gradual decline of computed tomography (CT) derived fractional flow reserve (FFRCT); and (2) to identify the predictive factors of an FFRCT decline below the pathological value of 0.80 in no apparent CAD vessels. Methods A total of 1058 outpatients with suspected CAD and who underwent CT angiography (CTA) with FFRCT analysis between January 2017 and December 2019 were evaluated. Among them, 150 consecutive patients who had both a CTA coupled to an FFRCT analysis and an invasive angiogram showing &amp;lt;25% coronary stenosis were included for analysis. Vessels were divided into two groups according to FFRCT at the distal vessel: FFRCT &amp;gt;0.80 (n=317) and FFRCT ≤0.80 (n=114). ΔFFRCT was defined as the magnitude of the change in FFRCT from the proximal to the distal vessel. Plaque characterization and vessel morphology measurements were performed semi-automatically. Vessel constituents were characterized based on Hounsfield units (HU) into lumen volume (&amp;lt;−50 HU), non-calcified plaque (NCP) (−50–150 HU), and calcified plaque (&amp;gt;150 HU). Results FFRCT decreased continuously from the proximal to distal across the three major vessels in both FFRCT&amp;gt;0.80 and FFRCT ≤0.80 groups (Figure 1). Compared to FFRCT&amp;gt;0.80 group, NCP volume was significantly higher in all three major vessels in FFRCT ≤0.80 group (210.2±83.6 mm3 vs. 140.9±139.3 mm3 for the RCA, p=0.01; 177.5±150.2 mm3 vs. 133.2±112.2 mm3 for the LAD, p=0.04; 127.6±91.5 mm3 vs. 58.7±57.7 mm3 for the LCX, p&amp;lt;0.01). Next, we investigated the vessel parameters that correlated with ΔFFRCT. ΔFFRCT was correlated with lumen volume in FFRCT&amp;gt;0.80 group (r=−0.24, p&amp;lt;0.0001), whereas ΔFFRCT was correlated with NCP volume in FFRCT ≤0.80 group (r=0.42, p&amp;lt;0.001) (Figure 2). An NCP volume above 44.8 mm3 was the strongest predictor of distal FFRCT of ≤0.80 (area under the curve 0.69, p&amp;lt;0.0001, sensitivity 95%, specificity 39%). Conclusions FFRCT is affected by vascular morphology and plaque characteristics even in the early stage of coronary artery disease. Our study highlights that subclinical coronary artery disease strongly influences FFRCT by effects unrelated to coronary stenosis. The presence of NCP is a major predictor of the gradual decrease of FFRCT toward pathological values. Anatomical findings as vessel morphology and plaque characteristics should be taken into consideration when interpreting numerical values of FFRCT to avoid unnecessary referrals for invasive coronary angiography or percutaneous coronary intervention. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2

Investigation of coeliac trunk and superior mesenteric artery variations and literature review.

Aim:To evaluate the variations of coeliac trunk and superior mesenteric artery variations in Tekirdag province using computed tomography (CT) images. Methods: The data of the patients who underwent CT angiography for any reason via the hospital online PACS system were scanned retrospectively for celiac trunk and superior mesenteric artery variation. The frequency of variation in the study population, the variation type and distribution by gender were statistically analyzed. Results: A total of 2529 individuals, including 1703 (67.3%) men and 826 (32.7%) women, were included in the study. The prevalence of variation in the study group was 25.7% (n=650), and it was seen that there was a single variation in 579 (89.1%) individuals and a double variation in 71 (10.9%) individuals. The three most common variations were replaced right HA, LGA orginated replaced left HA, and common HA from SMA origin ( n= 340, 13.44 % ; n=120, 4,74 % and n=46, 1.82 %, respectively). Conclusion: Information the rates of these vascular variations provides contribution to surgical procedures and prevents more serious complications. Also, it should be carefully investigated in terms of other accompanying variation.

Validation of computed tomography angiography as a complementary test in the assessment of renal artery stenosis: a comparison with digital subtraction angiography.

Renal artery stenosis is an important cause of hypertension in children, accounting for 5-10% of cases. When suspected, noninvasive imaging options include ultrasound (US), computed tomography (CT) angiography and magnetic resonance (MR) angiography. However, digital subtraction angiography (DSA) remains the gold standard. To investigate the accuracy and inter-reader reliability of CT angiography in children with suspected renal artery stenosis. This is a retrospective study of patients suspected of having renal artery stenosis evaluated by both CT angiography and DSA between 2008 and 2019 at a tertiary pediatric hospital. Only children who underwent CT angiography within 6months before DSA were included. CT angiography studies were individually reviewed by two pediatric radiologists, blinded to clinical data, other studies and each other's evaluation, to determine the presence of stenosis at the main renal artery and 2nd- and 3rd-order branches. The sensitivity, specificity and accuracy were calculated using DSA as the reference. The effective radiation dose for CT angiography and DSA was also calculated. Kappa statistics were used to assess inter-reader agreement. Seventy-four renal units were evaluated (18 girls, 19 boys). The patients' median age was 8years (range: 1-21years). Overall, CT angiography was effective in detecting renal artery stenosis with a sensitivity of 85.7%, specificity of 91.5% and accuracy of 88.9%. There was moderate inter-reader agreement at the main renal artery level (k=0.73) and almost perfect inter-reader agreement at the 2nd/3rd order (k=0.98). However, the sensitivity at the 2nd- and 3rd-order level was lower (14.3%). CT angiography provided excellent negative predictive value for evaluating renal artery stenosis at the main renal artery level (90.1%) and at the 2nd- or 3rd-order branches (82.7%). The median effective dose of CT angiography studies was 2.2mSv (range: 0.6-6.3) while the effective dose of DSA was 13.7mSv. CT angiography has high sensitivity and specificity at the main renal artery level with a lower radiation dose than previously assumed. Therefore, it can be used as a diagnostic tool in patients with low to medium risk of renal artery stenosis, and as a screening and treatment planning tool in patients at high risk.

Computed Tomography Angiography Prediction of Successful Trasnscatheter Embolization for Type II Endoleak of Endovascular Abdominal Aortic Aneurysm Repair

PurposeTo evaluate the utility of computed tomography (CT) angiography before transarterial embolization (TAE) in predicting TAE’s technical success for type II endoleaks (T2ELs). Materials and MethodsFifty-eight patients (mean age, 74.4 years; range, 46–89 years) who underwent attempted TAE for T2EL from July 2014 to August 2019 and underwent CT angiography before the procedure were included. Each CT angiography result was assessed for a feeding artery that was traceable over its entire course from either the superior mesenteric artery or the internal iliac artery to the endoleak cavity. TAE was performed using coils and was considered technically successful if embolization of the endoleak cavity and feeding artery was performed. The technical success rates were compared between patients with and without traceable feeding arteries. ResultsA fully traceable feeding artery supplying 75% (44/59) of endoleaks in the cohort was identified. TAE was technically successful in 95% (42/44) of these cases but only in 13% (2/15) of the cases without a fully traceable feeding artery (P < .001). When the inferior mesenteric artery was the feeding artery, it was always fully traceable, and TAE was technically successful in 100% (33/33) of the cases. When a lumbar artery was the feeding artery, it was fully traceable in only 42% (11/26) of the cases. When the lumbar artery was not fully traceable, TAE was technically successful in only 13% (2/15) of the cases. ConclusionsThe traceability of a feeding artery over its entire course to an endoleak cavity using CT angiography was associated with TAE’s technical success. Lumbar feeding arteries were less likely to be fully traceable. TAE’s high failure rate when the feeding artery was not fully traceable suggests that translumbar embolization can be considered as an initial approach for theses patients.

Diagnostic sensitivity and specificity of CT angiography for renal artery stenosis in children.

Children with suspected renal artery stenosis (RAS) are screened with renal Doppler ultrasonography or computed tomography (CT) angiography/magnetic resonance (MR) angiography depending on institutional preference. CT angiography produces images with superior resolution, allowing higher quality multiplanar two-dimensional reformats and three-dimensional reconstructions. However, there is a paucity of data in the literature regarding the utility and diagnostic performance of renal CT angiography in pediatric RAS. The objective of this study is to retrospectively review our experience with renal CT angiography in the diagnosis of pediatric RAS relative to digital subtraction angiography (DSA) as the reference standard. All patients 0-18years of age who underwent CT angiography for evaluation of RAS as a cause of hypertension between January 2012 and May 2019 were identified for the study. A total of 131 patients were identified, 23 of whom had DSA correlation. Twenty-three patients (17 boys, 6 girls) with a mean age of 6years 3months (range: 3months to 14years 7months) were included in this study. Of the 59 renal arteries studied by DSA, 22 were abnormal on CT angiography and 20 were abnormal on DSA. Of the 59 renal arteries, CT angiography was true positive in 18 and true negative in 35. The sensitivity and specificity of CT angiography for RAS diagnosis were 90.0% and 89.7%, respectively. CT angiography identified all cases of main RAS. Renal CT angiography has a high sensitivity and specificity for pediatric RAS diagnosis in patients referred for DSA.

Differences in valve morphology between patients with bicuspid and tricuspid aortic valve

Abstract Background Bicuspid aortic valve (BAV) patients represent a significant minority of severe aortic stenosis (AS) patients undergoing transcutaneous aortic valve implantation (TAVI). These patients demonstrate anatomic differences compared to tricuspid aortic valve (TAV). Ethnicity is associated with different valve morphologies characterized by Siever's classification. Purpose We aim to evaluated the prevalence of BAV subtypes and the differences in valve morphology and aortic root dimensions between BAV and TAV in patients undergoing computed tomography (CT) before TAVI. Methods In five Israeli medical centers, 131 patients with BAV and 674 patients with TAV underwent CT angiography. BAV morphology was defined according to the number of commissures and raphe, following Siever's classification. Aortic root dimensions were measured at the level of the aortic annulus, sinus of Valsalva (SOV), and sino-tubular junction (STJ). Finally, Agatston score unit (AU) for valve calcification was evaluated. Results Type 0 accounted for 27% (36/131), Type IA for 63% (82/131), Type IC for 9% (12/131), and Type 2 for 1% (1/131). Calcium score in BAV patients was significantly higher compared to TAV patients, 4000±1897 vs. 2152±1216 AU; respectively (P&amp;lt;0.001). Distance from the annulus to the left main coronary artery was greater in BAV patients compared to TAV (13.8±3.6 mm vs. 12.8±2.8 mm; respectively, P&amp;lt;0.001), similar distance from annulus to right coronary artery was observed in BAV and TAV patients (16.7±3.7 mm vs. 15±3 mm; respectively, P&amp;lt;0.001). Aortic annulus perimeter was greater in BAV than TAV patients (79.3±11mm vs. 73±8.7mm, respectively, P&amp;lt;0.001), as well as SOV perimeter (35.7±4.5mm vs. 32±3.7mm, respectively, P&amp;lt;0.001), and STJ perimeter (32.3±5mm vs. 27±3.3 mm; respectively, P&amp;lt;0.001). Conclusion In Israel, AS patients showed more frequently type 1A BAV. BAV patients have larger aortic root dimensions and higher calcium burden than TAV patients. Funding Acknowledgement Type of funding source: None

Clinical effects of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck

Objective: To explore the clinical effects of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck. Methods: From January 2016 to August 2019, 10 male patients, aged from 20 to 52 years with post-burn facial and cervical scar deformities, were admitted to the First People's Hospital of Zhengzhou, with the size of scar ranging from 15 cm×7 cm to 23 cm×11 cm. In the first stage, a cylindrical skin and soft tissue expander with rated capacity ranging from 400 to 600 mL was placed in the frontal-parietal region. Another cylindrical expander with rated capacity ranging from 50 to 100 mL was placed in the temporal region of the patient with scars in front of the ear and in cheek. The injection time was 3 to 5 months with the total injection volume being 1.5 to 2.5 times of the rated capacity of expander. In the second stage, the superficial temporal artery frontal branch and its branches were explored, the expander was removed, the scars in the face and neck were conducted resection and contracture relaxation, and the single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region for reconstruction was performed. When the branches of the superficial temporal vessels were difficult to be detected by Doppler ultrasonic blood stream detector, the patient underwent computed tomography (CT) angiography and three-dimensional reconstruction. The donor site in frontal-parietal region was directly sutured, and the wound of the exposed donor site at the pedicle and temporal region was temporarily covered with scar skin. After the suture wound was healed and the hair in expanded flap grew out, hair removal and laser hair removal were performed. Three to four weeks after transplantation of expanded flap, the flap pedicle was cut off, restored, and trimmed in the third stage. The status about the completion of operation, the implantation of expander in the temporal region, CT angiography and three-dimensional reconstruction were recorded. The effective resection area of expanded flap, the length across the midline and the length of the pedicle, and the survival status of the expanded flap and complications after operation were observed. The appearance of donor and recipient sites, the scar recurrence, the appearance and function improvement of patients, and the satisfaction degree of patients were followed up. Results: All the 10 patients successfully completed three stages of operation, of which 6 patients had an auxiliary expander placement in the temporal region, and 5 patients underwent CT angiography and three-dimensional reconstruction. The effective resection area of expanded flap ranged from 18 cm×8 cm to 25 cm×13 cm. The distal end of the flap across the midline extended 4-6 cm to the opposite side, and the length of pedicle was 2-6 cm. All the expanded flaps of patients survived well after formation and transfer. The venous reflux disorder and obvious swelling occurred in 6 patients at the distal end of the flap after operation, and the blood supply recovered after acupuncture bloodletting, etc. Follow-up of 6 to 24 months showed that the color, texture, and thickness of the expanded flaps were similar to those of the facial skin, and no recurrence of scar was observed; the incision in the donor site of the frontal-parietal region was concealed, the hair growth of the temples and head was normal, and the reconstructed hairline was natural; compared with those before operation, the appearance, head-up, mouth-opening, and other functions of patients were significantly improved; the patients were satisfied with the effect of reconstruction. Conclusions: Clinical application of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck can achieve a good appearance and function, and the donor site shows good shape, which enriches the application range of the trans-regional blood supply flap. It is a reliable method for reconstruction of large scar deformities in the face and neck.

Abstract No. 380 Comparing contrast exposure to patients that underwent computed tomography angiography, 99mtechnetium-labeled red blood cell scintigraphy, and catheter angiography in gastrointestinal bleeding

To investigate the amount of contrast administered to patients that underwent computed tomography (CT) angiography to catheter angiography (CA), 99mTechnetium-Labeled Red Blood Cell (RBC) Scintigraphy to CA, and CA alone in the setting of gastrointestinal bleeding (GIB), while considering the potential nephrotoxic effects of iodinated contrast. From data collected between January 2014 to September 2019, 173 CAs performed for GIB, including massive, ongoing, and obscure bleeding, were retrospectively identified in patients with preprocedural CT angiography and RBC scintigraphy. Three groups were identified and the amount of contrast from these groups was compared using an ANOVA. The creatinine from these groups was also collected to examine possible side effects of increase exposure to iodinated contrast. 84 patients underwent CT angiography, 51 patients underwent RBC scintigraphy, and 38 patients underwent a CA without a prior scan. The amount of contrast administered to patients among the three groups was statistically significant (P = <0.001). When evaluating the individual groups there was a statistically significant difference between the group that was exposed to both CT angiography and CA vs. RBC scintigraphy and CA (P ≤ 0.001) and CT angiography and CA versus CA alone (P ≤ 0.001). The amount of positive CTAs (58) that resulted in positive CA was 40. The amount of CAs alone that resulted positive was 14 of 38. Overall, there was no statistical significance in the change in creatinine between the groups. Patients that received a CTA with CA were exposed to much larger doses of contrast compared to the other groups. However, a positive CTA highly correlates with a positive CA, which is not the case with CAs alone. Additional contrast associated with CT angiography does not result in increased nephrotoxicity.

Abstract No. 419 Comparing patient radiation exposure while using different methods to explore potential gastrointestinal bleeds

To investigate the amount of radiation that patients were exposed to while undergoing computed tomography (CT) angiography and catheter angiography (CA), 99mTechnetium-Labeled Red Blood Cell (RBC) Scintigraphy and CA, and CA alone in the setting of a potential gastrointestinal bleed (GIB). From data collected between January 2014 to September 2019, 173 CAs performed for GIB, including massive, ongoing, and obscure bleeding, were retrospectively identified in patients with preprocedural CT angiography and RBC scintigraphy. Three groups were identified, and the amount of radiation exposure collected from each group was compared using an ANOVA. 84 patients underwent CT angiography, 51 patients underwent RBC scintigraphy, and 38 patients underwent a CA only. The amount of radiation exposure to patients among the three groups was statistically significant (P ≤ 0.023). When evaluating the individual groups there was a statistically significant difference between the group that was exposed to both CT angiography and CA versus RBC scintigraphy and CA (P ≤ 0.05). The amount of positive CTAs (58) that resulted in positive CA was 40. The amount of CAs alone that resulted positive was 14 of 38. Patients that received a CTA with CA were exposed to much larger doses of radiation when compared to the other groups. However, the higher positive correlation between CTA and a positive CA when compared to RBC scintigraphy to CA or CA alone signifies that patients may be saved unwarranted amounts of radiation by receiving a CTA as a screening tool for GIB. Though the average age of this cohort is about 66, this is especially important while considering patients in their youth.

Role of coronary artery calcium score in prediction of coronary artery stenosis in symptomatic patients with suspected coronary artery disease

Introduction The coronary artery calcium (CAC) score has been proposed as an alternative approach for stratifying cardiovascular risk. Aim To assess the role of CAC score in prediction of coronary stenosis in symptomatic patients with intermediate probability for coronary artery disease (CAD). Patients and methods A total of 80 symptomatic patients with intermediate probability for CAD underwent thorough history taking and clinical examination. Computed tomographic (CT) scan was done for all patients. A total of 48 (60%) patients with CAC score less than 400 HU (group A) underwent CT angiography: 30 (62.5%) patients had significant coronary stenosis (SCS) and were referred to invasive coronary angiography (ICA), whereas 18 (37.5%) patients had no SCS. Overall, 32 (40%) patients with CAC score more than 400 HU (group B) were referred directly for ICA. Results ICA for 62 patients was performed: 30 (62.5%) patients were referred from group A, and all had SCS (100%), whereas 30 (93.7%) patients of 32 referred from group B had SCS. Using logistic regression analysis, CAC score was the only predictor of SCS (P=0.024). Receiver operating characteristic curve data revealed CAC more than 311.2 HU as a cutoff point for prediction of SCS, with specificity of 85.0%, sensitivity of 63.3%, and area under the curve of 74.7%. CT angiography sensitivity for detection of stenosis less than or equal to 50%, stenosis more than 50%, and stenosis more than 70% was 73, 62.5, and 94%, respectively; specificity of 96.8, 99.4, and 99.4%, respectively; and overall accuracy of 85.0, 81, and 96.9%, respectively, with negative predictive value to rule out SCS 99%. Conclusion CAC score is predictive for the presence of SCS in patients, with intermediate probability for CAD.

Morphometric evaluation of aortic coarctation and collateral circulation using computed tomography in the adult population.

Background Analysis of morphometric details of aortic coarctation and collateral circulation using computed tomography (CT) and its impact on clinical symptoms is a perspective which is missing in the published literature. Purpose To perform CT-based qualitative and quantitative evaluation of aortic coarctation and collateral circulation with reference to clinical symptoms. Material and Methods The study comprised 2022 patients who underwent CT angiography. If aortic coarctation was seen, the patients underwent evaluation of its anatomy and associated clinical symptoms. Results Aortic coarctation was found in 33 patients. Follow-up (median 2476 days; range 1692–3543) was performed in 31 (94%) individuals. In this group (median age 42 years; range 30–52.5 years), median stenosis at the site of coarctation was 70% (range 58–85%) of the lumen area, with 17 (55%) patients presenting with significant (≥70%) stenosis. Patients with significant stenosis had a greater right and left internal mammary artery diameter ( P = 0.0070 and P = 0.0114, respectively) than those with mild stenosis. Patients with significant coarctation stenosis revealed hypertension and headache more commonly than those with mild stenosis (17 vs. 9, P = 0.01 and 10 vs. 2, P = 0.02), respectively. In patients who underwent intervention, a decrease in prevalence of hypertension (19 vs. 0, P = 0.008) and headache (12 vs. 3, P = 0.010) were observed in the follow-up. Conclusion CT enables quantitative and qualitative evaluation of aortic coarctation anatomy, including stenosis at the site of coarctation, and collateral circulation. In adult patients with aortic coarctation, the prevalence of hypertension and headache is related to the degree of stenosis at the site of coarctation and decreases after intervention.

Evaluation of the positional relationship between femoral arteries and distal screws in the proximal femoral intramedullary nail for preventing iatrogenic vascular injury

Background and AimsIatrogenic vascular injury associated with distal screw in the intramedullary nail for femoral trochanteric fracture is a rare but serious complication. This study aimed to investigate the positional relationship between distal screws and superficial (SFA), deep (DFA), and perforating femoral artery (PFA) using computed tomography (CT) angiography and to identify the risk factors of vascular injury. Patients and MethodsThirty-eight patients (11 patients who underwent osteosynthesis with proximal femoral intramedullary nail and 27 healthy people) who underwent CT angiography were included. The distance from the great trochanter tip and insertion angle from posterior condylar axis (reference line) of the distal screws were measured, and the presence rates and distances from the femur of each artery within the insertion angle were investigated. ResultsThe distance from the great trochanter tip to the distal screw was 142.5 ± 8.8 mm. The insertion angle from the reference line was 27.3°±15° The measurement points were set at 130, 140, and 150 mm distal from the great trochanter tip, and the assumed insertion angle as 27°±15° Within this angle, the presence rates and distances were 50.8%/34.2 ± 7.0 mm (130 mm), 38.5%/34.3 ± 6.0 mm (140 mm), 30.8%/33.4 ± 6.0 mm (150 mm) in SFA; 12.3%/14.2 ± 3.3 mm (130 mm), 3.1%/13.1 ± 5.9 mm (140 mm), and 0% (150 mm) in DFA; and 0% (130−150 mm) in PFA. The presence rate of DFA increased at the posteromedial area in the thigh, and the distance from the femur became closer. ConclusionWithin the angle that distal screws were likely to be inserted, the risk of DFA injury was the highest. Therefore, anatomical reduction of the femoral neck anteversion should be performed so that the distal screw will be inserted towards the anteromedial area in the thigh, and great attention should be paid not to over-drill the medial femoral cortex.

P3378Differences in valve morphology and aortopathy between patients with bicuspid and tricuspid aortic valves: a Computed Tomography Study

Abstract Background Transcatheter aortic valve implantation (TAVI) has been shown safe and feasible in patients with bicuspid aortic valve (BAV) morphology. Evaluation of differences in valve morphology and aortic root dimensions in patients with BAV in comparison to patients with tricuspid aortic valve (TAV) is important for the spread of TAVI in patients with BAV. Purpose The present study evaluated the prevalence of BAV subtypes and the differences in valve morphology and aortic root dimensions between BAV and TAV in patients undergoing computed tomography (CT) before TAVI. Methods In five medical centers in Israel, 104 patients (69±13.5 years) with BAV and 105 patients (81±8.22 years) with TAV underwent CT angiography. BAV morphology was defined according to the number of commissures and raphe following Siever's classification. Functional BAV was defined as 3 cusps with focal fusion of 1, 2, or 3 commissures. Aortic root dimensions were measured at the level of the aortic annulus, sinus of Valsalva (SOV), sino-tubular junction (STJ), and ascending aorta (AA). Membranous septum (MS) length was measured in coronal view. The volume and agatston score of aortic valve calcification were evaluated. Results Type 0 account for 22% (23/104), type IA for 58% (60/104), Type IC for 9% (9/104), functional BAV for 11% (12/104). Type IB and II were not found in the studied population. As compared with TAV, patients with BAV have significantly larger aortic annulus area, SOV area, STJ area and AA Area; however, the ellipticity index of aortic annulus, SOV, STJ, and AA were similar. MS length was significantly smaller in patients with BAV compared to patients with TAV (6.4±2.3 mm vs. 8.1±2.7mm; retrospectively; P&lt;0.001) and the volume of aortic valve calcifications was significantly higher in BAV compared to TAV patients: 2.3±1.6 ml3 vs. 1.4±1.2 ml3 retrospectively; P=0.003). Conclusions In Israel, patients with BAV showed more frequently type 1A BAV. BAV patients have larger aortic root dimensions than patients with TAV without difference in regard to the ellipticity index. MS length was smaller and the amount of aortic leaflet calcifications was higher in patients with BAV. These findings may have important impact on procedural outcome.

Prospective Comparison of 70-kVp Single-Energy CT versus Dual-Energy CT: Which is More Suitable for CT Angiography with Low Contrast Media Dosage?

To compare the objective and subjective image qualities between single-energy computed tomography (CT) at 70 kVp and virtual monoenergetic imaging (VMI) of dual-source dual-energy CT for CT angiography with 180 mgI/kg. Total 63 patients scanned with 180 mgI/kg were randomly divided into two groups: Group A (32 patients) underwent CT angiography at 70-kVp, and Group B (31 patients) underwent dual-energy CT. VMI sets were generated at 10-keV increments between 40 and 100 keV. We calculated aortic attenuation, contrast-to-noise-ratio (CNR), signal-to-noise-ratio, figure of merit of CNR, and effective dose for each protocol. Three radiologists scored overall image quality and various arteries' visibility using a four-point scale. Quantitative and qualitative comparisons between 70 kVp and VMI with the highest CNR were performed with the two-tailed t test or Kruskal-Wallis test. The 40-keV images offered the highest CNR among VMIs. Aortic attenuation at 70 kVp was significantly lower than that at 40 keV (p < 0.001). However, the signal-to-noise-ratio, CNR, and figure of merit of CNR were significantly higher at 70 kVp than those at 40-keV (p < 0.001, p < 0.05, and p < 0.05, respectively). The effective dose of each group was almost equal. The qualitative visibility scores for various arteries, except the ascending and upper-abdominal aorta, were also better at 70 kVp than those at 40 keV. Aortic attenuation at 70 kVp with 180 mg I/kg was lower than that of VMI at 40 keV, and the objective and subjective image qualities were higher at 70 kVp than those at 40 keV.

Correlation of CT Angiography and 99mTechnetium-Labeled Red Blood Cell Scintigraphy to Catheter Angiography for Lower Gastrointestinal Bleeding: A Single-Institution Experience

To investigate the correlation of computed tomography (CT) angiography and 99mTechnetium-labeled red blood cell (RBC) scintigraphy to catheter angiography (CA) in the management of lower gastrointestinal bleeding (LGIB) while considering potential nephrotoxic effects of iodinated contrast. From November 2012 to August 2017, 223 CAs performed for LGIB, including massive, ongoing, and obscure bleeding, were retrospectively identified in patients with pre-procedural CT angiography or RBC scintigraphy. Positive correlations and sensitivities were calculated for CT angiography and RBC scintigraphy using CA results as reference. Correlations were then compared while considering certain clinical presentations of LGIB. Contrast dose was compared with maximum creatinine recorded 48-72 hours after. Thirty-eight patients underwent CT angiography; 173 patients underwent RBC scintigraphy; and 12 patients completed both studies. CT angiography had a positive correlation of 67.7% (95% confidence interval [CI]: 57.0, 76.7) and sensitivity of 85.2% (95% CI: 66.3, 95.8), whereas RBC scintigraphy had a positive correlation of 29.3% (95% CI: 27.7, 31.0) and sensitivity of 94.4% (95% CI: 84.6, 98.8). CT angiography had higher positive correlation across all clinical presentations. No dose-toxicity relationship was observed between contrast and renal function (R2: 0.008), nor was there a difference in incidence of contrast-induced nephropathy between CT angiography and RBC scintigraphy (P= .30). CT angiography has greater positive correlation to CA than RBC scintigraphy for assessing LGIB in active stable as well as hemodynamically unstable LGIB. As such, greater adoption of CT angiography may reduce the number of nontherapeutic CAs performed. Additional contrast associated with CT angiography does not result in increased nephrotoxicity.