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To compare the radiation dose and diagnostic ability of the 100-kVp protocol, based on the contrast noise ratio (CNR) index, during coronary artery bypass graft (CABG) vessels with those of the 120-kVp protocol. For the 120-kVp scans (150 patients), the targeted image level was set at 25 Hounsfield units (HU) (CNR120 = iodine contrast/25 HU). For the 100-kVp scans (150 patients), the targeted noise level was set at 30 HU to obtain the same CNR as in the 120-kVp scans (i.e. using 1.2-fold higher iodine contrast, CNR100 = 1.2 × iodine contrast/(1.2 × 25 HU) = CNR120). We compared the CNRs, radiation doses, detection of CABG vessels and visualisation scores of the scans acquired at 120 and 100 kVp, respectively. At the same CNR, the 100-kVp protocol may help reduce the radiation dose by ⁓30% compared with the 120-kVp protocol, without degradation of diagnostic ability during CABG.

Purpose: This study assessed whether patient-specific contrast enhancement optimizer simulation software (p-COP) can reduce the contrast material (CM) dose compared with the conventional body weight (BW)-tailored scan protocol during transcatheter aortic valve implantation-computed tomography angiography (TAVI-CTA) in patients with aortic stenosis. Methods: We used the CM injection protocol selected by the p-COP in group A (n = 30). The p-COP uses an algorithm that includes data on an individual patient’s cardiac output. Group B (n = 30) was assigned the conventional BW-tailored CM injection protocol. We compared CM dose, amount of CM, injection rates, and computed tomography (CT) value in the abdominal aorta between the two groups and classified them as acceptable (>280 Hounsfield units (HU)) or unacceptable (Results: Group A received 56.2 ml CM and 2.6 ml/sec of injection, and group B received 76.9 ml CM and 3.4 ml/sec of injection (p < 0.01). The CT value for the abdominal aorta at the celiac level was 287.0 HU in group A and 301.7HU in group B (p = 0.46). The rate of CT value for acceptable (280 HU or more) and unacceptable (less than 280 HU) were 22 and 8 patients in group A, and 24 and 6 patients in group B, respectively (p = 0.76). Conclusion: The p-COP reduced the CM dosage, and the injection rate was approximately 30% in patients with aortic stenosis compared with the BW-tailored scan protocol during TAVI-CTA.

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

To evaluate whether the patient-specific contrast enhancement optimizer simulation software (p-COP) is useful for predicting contrast enhancement during whole-body computed tomography angiography (WBCTA). We randomly divided the patients into two groups using a random number table. We used the contrast material (CM) injection protocol selected by p-COP in group A (n = 52). The p-COP used an algorithm including data on the individual patient's cardiac output. Group B (n = 50) was assigned to the conventional CM injection protocol based on body weight. We compared the CT number in the abdominal aorta at the celiac artery level between the two groups and classified them as acceptable ( 280 HU) and unacceptable ( 279 HU) based on the optimal CT number for the WBCTA scans. To evaluate the difference in both injection protocols, we compared the visual inspection of the images of the artery of Adamkiewicz in both protocols. The CM dosage and injection rate in group A were significantly lower than those in group B (480.8 vs. 501.1 mg I/kg and 3.1 vs. 3.3 ml/s, p 0.05). The CT number of the abdominal aorta at the celiac level was 382.4 ± 62.3 HU in group A and 363.8 ± 71.3 HU in group B (p = 0.23). CM dosage and injection rate were positively correlated to cardiac output for group A (r = 0.80, p 0.05) and group B (r = 0.16, p 0.05). The number of patients with an acceptable CT number was higher in group A [46/6 (86.7%)] than in group B [43/7 (71.4%)], but not significant (p = 0.71). The visualization rate for the Adamkiewicz artery was not significantly different between groups A and B (p = 0.89). The p-COP was useful for predicting contrast enhancement during WBCTA with a lower CM dosage and a lower contrast injection rate than that based on the body weight protocol. In patients with lower cardiac output a reduction in contrast injection rate and CM dosage did not lead to a reduced imaging quality, thus particularly in this group CM dosage can be reduced by p-COP.

Background: To compare the effect of obtaining the anteroposterior scout view (APSV) with that of posteroanterior scout view (PASV) on mammary gland dose in pediatric patients. Methods: We used a pediatric anthropomorphic phantom with a 64 detector-row computed tomography (CT) scanner using the APSV or PASV protocol of the chest. A real-time skin dosimeter was placed on the scanner gantry and pasted onto the phantom surfaces of the right and left mammary glands. We compared the real-time skin dosimeter values in the right and left mammary glands between the APSV and PASV protocols at different tube voltages. Results: Compared with APSV, it is possible to reduce the exposure dose by approximately 80% using PASV at different tube voltages (p < 0.05). Conclusion: Obtaining the PASV was helpful in reducing the mammary gland dose by approximately 80% in pediatric patients than that of APSV without deteriorating the image quality of the main scan.

Background: To investigate optimizing the use of different beam shaping filters (viz. small, medium and large) when using different tube voltages during the newborn chest computed tomography (CT) examination. Methods: We used pediatric anthropomorphic phantoms with a 64 detector-row CT scanner while scanning the chest. A real-time skin dosimeter was placed on the scanner gantry and was inserted into the phantom center of the body, the surface of the body back, and the right and left mammary glands. We performed and compared six scan protocols using small, medium, and large beam shaping filters at 80 and 120 kVp protocols. Result: There were no significant differences in the image noise for the chest scan among the different beam shaping filters. By using the large beam shaping filter at 80 kVp, it was possible to reduce the exposure dose by 5% in comparison with the small beam shaping filter, and by 10% in comparison with the medium beam shaping filter. By using the large beam shaping filter at 120 kVp, it was possible to reduce the exposure dose by 15% in comparison with the small beam shaping filter and by 20% in comparison with the medium beam shaping filter (p < 0.01). Conclusion: The large beam shaping filter had the most dose reduction effect during newborn chest CT. However, the exposure dose reduction rate was low when the lower tube voltage was used.

We retrospectively evaluated the visualization of pediatric coronary computed tomography angiography (CCTA) images by using the 64-detector row CT scanner between the electrocardiogram-gated helical scan and non-electrocardiogram-gated helical scan.From January 2015 to March 2019, 100 children who underwent CT angiography examination were retrospectively enrolled. Group A consisted of 50 patients with electrocardiogram-gated helical scan. Group B consisted of 50 patients with non-electrocardiogram-gated helical scan. All patients were scanned using a 64-detector row CT scanner (LightSpeed VCT), and helical scans were acquired. The CT scanning parameters were 0.4-s rotation, 0.625-mm slice thickness, 0.24 (group A) helical pitch (beam pitch), 1.375 (group B) helical pitch (beam pitch), 80 kVp, and 50-300 mA (noise index 40). A retrospective method was used for electrocardiogram gated. To compare the radiation dose, CT volume dose index (CTDIIn group A, CTDIIn 64-row multidetector computed tomography (MDCT), the visualization rates for the proximal and distal coronary arteries were significantly higher in the electrocardiogram-gated scan, but the exposure dose was several times higher in the pediatric CCTA. For accurate diagnosis in pediatric coronary arteries, electrocardiogram-gated helical scan should be performed.

To investigate the pediatric eye lens entrance surface dose for both axial scan modes without an active collimator and helical scan modes with an active collimator on 64 detector-row computed tomography (CT) scanner. We used three pediatric anthropomorphic phantoms with axial and helical scan modes from the superior orbitomeatal line to the crown of the head. We compared the measured dose values of the real-time skin dosemeter at the surfaces of the lens and the image noise at different scan modes. The median measured dose values for the lens of newborn, 1-year-old and the 5-year-old phantom were 31.3, 0.97 and 0.65 mGy, respectively, in the axial scan mode and 0.89, 1.21 and 0.71 mGy, respectively, in the helical scan mode. Compared with helical scans with an active collimators, axial scans can reduce the lens dose by ∼10% during head CT on 64 detector-row CT scanner without deterioration of image noise.

OBJECTIVE We developed a patient-specific contrast enhancement optimizer (p-COP) that can exploratorily calculate the contrast injection protocol required to obtain optimal enhancement at target organs using a computer simulator. Appropriate contrast media dose calculated by the p-COP may minimize interpatient enhancement variability. Our study sought to investigate the clinical utility of p-COP in hepatic dynamic computed tomography (CT). METHODS One hundred thirty patients (74 men, 56 women; median age, 65 years) undergoing hepatic dynamic CT were randomly assigned to 1 of 2 contrast media injection protocols using a random number table. Group A (n = 65) was injected with a p-COP-determined iodine dose (developed by Higaki and Awai, Hiroshima University, Japan). In group B (n = 65), a standard protocol was used. The variability of measured CT number (SD) between the 2 groups of aortic and hepatic enhancement was compared using the F test. In the equivalence test, the equivalence margins for aortic and hepatic enhancement were set at 50 and 10 Hounsfield units (HU), respectively. The rate of patients with an acceptable aortic enhancement (250-350 HU) for the diagnosis of hypervascular liver tumors was compared using the χ test. RESULTS The mean ± SD values of aortic and hepatic enhancement were 311.0 ± 39.9 versus 318.7 ± 56.5 and 59.0 ± 11.5 versus 58.6 ± 11.8 HU in groups A and B, respectively. Although the SD for aortic enhancement was significantly lower in group A (P = 0.006), the SD for hepatic enhancement was not significantly different (P = 0.871). The 95% confidence interval for the difference in aortic and hepatic enhancement between the 2 groups was within the range of the equivalence margins. The number of patients with acceptable aortic enhancement was significantly greater in group A than in group B (P < 0.01). CONCLUSIONS The p-COP software reduced interpatient variability in aortic enhancement and obtained acceptable aortic enhancement at a significantly higher rate compared with the standard injection protocol for hepatic dynamic CT.

PURPOSE To compare the radiation dose and image quality using the conventional method for performing the front and side scout view and a new method for performing the side scout view, and then correct the table height at the scan isocenter and perform the front scout view. METHODS We retrospectively analyzed fifty-six children who had underwent computed tomography (CT) examination between June 2014 and August 2018. We divided them into two groups. The conventional method was performed in 3 steps: 1. obtain the front scout view, 2. obtain the side scout view, and 3. main scan. Without table position correction, the new method was performed in 4 steps: 1. obtain the side scout view with table position correction, 2. patient correction at the scan isocenter, 3. obtain the front scout view, and 4. main scan. We used a 64-row CT scanner (LightSpeed VCT; GE Healthcare). Scan parameters were tube voltage 80 kV, automatic tube current modulation, noise index 16, slice thickness 5 mm, rotation time 0.4 s/rot, helical pitch 1.375, and reconstruction kernel standard. We recorded the volume dose index (CTDIvol) and dose length product (DLP) on the CT console and compared the radiation dose in both groups. To evaluate the image quality in both groups, the mean standard deviation of CT number (SD value) was measured within an approximately 5-10 mm2 circular region of interest. We measured the scan length of the pediatric patient and accuracy of pediatric positioning at the CT examination. A grid was displayed on the CT axial image, taken to evaluate the error from the scan isocenter during alignment, and the error between the height of half the body thickness and the scan isocenter was recorded. RESULTS Scan lengths were median (minimum-maximum) values of 16.2 cm (10.8-21.5 cm) and 16.8 cm (11.5-23.0 cm). There were no significant differences in the scan length between both groups (p=0.47). In the group with table position correction, median (minimum-maximum) values for CTDIvol, DLP and SD value were 0.40 mGy (0.3-0.7 mGy), 7.6 mGy･cm (4.4-11.5 mGy･cm), and 24.0 HU (18.3-37.5 HU), respectively. In the group without the table position correction, median (minimum-maximum) values for CTDIvol, DLP and SD value were 0.40 mGy (0.3-0.6 mGy), 7.1 mGy･cm (4.2-13.8 mGy･cm), and 20.3 HU (11.3-28.8 HU), respectively. There were no significant differences in the CTDIvol and DLP values between both groups (p=0.42 and p=0.44, respectively); however, there were significant differences in the SD value in both groups (p

Penile calciphylaxis is rarely reported in dialysis patients.We experienced cases of dialysis patients who had penile calciphylaxis between 2003 and 2020.Seven patients undergoing dialysis were treated for penile necrosis (hemodialysis [HD], 5; peritoneal dialysis [PD], 1; hybrid therapy comprising PD and HD, 1). Their mean age was 62.8 years and their mean dialysis vintage 116.1 months. All had severe penile pain and were clinically diagnosed with calciphylaxis. Four received partial penectomy and three received percutaneous transluminal angioplasty (PTA) due to rapid aggravation. The number of analgesia types and the critical-care pain observation tool score significantly decreased after invasive treatment (both, p = 0.008). The 90-day and 1-year survival rates after onset were 85.7% and 57.1%, respectively.In dialysis patients, penile calciphylaxis has poor prognosis; however, invasive treatments for pain management are effective. PTA may be beneficial in dialysis patients in poor condition.

To improve its diagnosis on contrast-enhanced dynamic CT (CE-DCT) scans, contrast injection protocol must yield stable arterial contrast enhancement. To investigate how the body-water distribution and the body composition, calculated by bioelectrical impedance analysis (BIA), affect aortic and hepatic enhancement on CE-DCT scans. 236 patients with liver cirrhosis underwent CE-DCT before BIA. The CT number (in Hounsfield units, HU) of the abdominal aorta at the celiac artery level on unenhanced scans and during the hepatic arterial phase (HAP) scans was recorded. And, the mean CT number of the hepatic parenchyma of both hepatic lobes at the celiac artery level on unenhanced and portal venous phase (PVP) scans was recorded. We calculated changes in the iodine dose per contrast enhancement (mgI/HU) (IDCE) to evaluate the effect of the patient age and of various constituents of the body composition by performing BIA. The IDCE of the abdominal aorta during HAP was 121.5 ± 32.1 mgI/HU; it was 698.7 ± 211.1 mgI/HU in the hepatic parenchyma during the PVP. Among the parameters used in our BIA, the total body weight (TBW) was the most important factor affecting the IDCE of the liver abdominal aorta on CE-DCT scans acquired during the HAP (r = 0.83). The TBW and the skeletal muscle index most strongly affected the IDCE of the hepatic parenchyma on CE-DCT scans obtained during the PVP (r = 0.69). The TBW had the strongest effect on contrast enhancement. The skeletal muscle index exhibited the strongest correlation with hepatic parenchymal contrast enhancement during the PVP.

With technological improvements in the endovascular armamentarium, there have been tremendous advances in catheter-based femoropopliteal artery intervention during the last decade. However, standardization of the methodology for assessing outcomes has been underappreciated, and unvalidated peak systolic velocity ratios (PSVRs) of 2.0, 2.4, and 2.5 on duplex ultrasonography have been arbitrarily but routinely used for assessing restenosis. Quantitative vessel analysis (QVA) is a widely accepted method to identify restenosis in a broad spectrum of cardiovascular interventions, and PSVR needs to be validated by QVA. This multidisciplinary review is intended to disseminate the importance of QVA and a validated PSVR based on QVA for binary restenosis in contemporary femoropopliteal intervention.

Introduction To evaluate the effect of sex, age, height, cardiac output (CO), total body weight (TBW), body surface area (BSA), and lean body weight (LBW) on vessel enhancement of the ascending aorta in pediatric chest computed tomography angiography (c-CTA). Materials and Methods This retrospective study received institutional review board approval; parental prior informed consent for inclusion was obtained for all patients. All 50 patients were examined using our routine protocol; iodine (600 mg/kg) was the contrast medium (CM). Unenhanced and contrast-enhanced scans were obtained. We calculated the CM volume per vessel enhancement and performed univariate and multivariate linear regression analysis of the relationship between CM volume per vessel enhancement and each of the body parameters. Results All patient characteristics were significantly related to CM volume per vessel enhancement ( P < .05). Multivariate linear regression analysis revealed a significant correlation between CM volume per vessel enhancement and TBW, BSA, and LBW, but not the patient sex, age, CO, and height. The LBW model for CM volume per vessel enhancement yielded the highest determination coefficient (R2 = .913) and the lowest Akaike Information Criterion (400.324). Conclusions Our findings support the delivery of an iodine dose adjusted to the LBW at c-CTA.

Iliopsoas abscess in HD patients is rare. We examined nine HD patients with iliopsoas abscess (six men and five diabetes mellitus cases) treated between 2005 and 2015. Mean age and dialysis vintage at onset were 72 years and 109 months, respectively. Of the nine patients, four had lumbar orthopedic diseases, and two had all components of the classic triad of iliopsoas abscess at onset. All nine patients underwent percutaneous drainage, while seven underwent antimicrobial therapy. The most common pathogenic bacterium was methicillin-resistantStaphylococcus aureus(MRSA) (n = 5). Four patients had multilocular recurrence on the same side as the initial abscess and did not undergo CT before drainage catheter removal. Five patients died in the hospital, in which three died due to infectious diseases by MRSA. We suggest percutaneous drainage as the first-line therapy for HD patients with iliopsoas abscess and recommend combining antimicrobial therapy for MRSA, because of poor prognosis.

Background To determine whether machine learning with histogram analysis of coronary CT angiography (CCTA) yields higher diagnostic performance for coronary plaque characterization than the conventional cut-off method using the median CT number. Methods We included 78 patients with 78 coronary plaques who had undergone CCTA and integrated backscatter intravascular ultrasound (IB-IVUS) studies. IB-IVUS diagnosed 32 as fibrous- and 46 as fatty or fibro-fatty plaques. We recorded the coronary CT number and 7 histogram parameters (minimum and mean value, standard deviation (SD), maximum value, skewness, kurtosis, and entropy) of the plaque CT number. We also evaluated the importance of each feature using the Gini index which rates the importance of individual features. For calculations we used XGBoost. Using 5-fold cross validation of the plaque CT number, the area under the receiver operating characteristic curve of the machine learning- (extreme gradient boosting) and the conventional cut-off method was compared. Results The median CT number was 56.38 Hounsfield units (HU, 8.00–95.90) for fibrous- and 1.15 HU (−35.8–113.30) for fatty- or fibro-fatty plaques. The calculated optimal threshold for the plaque CT number was 36.1 ± 2.8 HU. The highest Gini index was the coronary CT number (0.19) followed by the minimum value (0.17), kurtosis (0.17), entropy (0.14), skewness (0.11), the mean value (0.11), the standard deviation (0.06), and the maximum value (0.05), and energy (0.00). By validation analysis, the machine learning-yielded a significantly higher area under the curve than the conventional method (area under the curve 0.92 and 95%, confidence interval 0.86–0.92 vs 0.83 and 0.75–0.92, p = 0.001). Conclusion The machine learning-was superior the conventional cut-off method for coronary plaque characterization using the plaque CT number on CCTA images.

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

To evaluate and compare the absorbed dose and image quality when applying a commercially produced fixation device (group A) and a vaccum mattress fixation device to pediatric patients (group B). We compared the absorbed dose and image noise between the groups at the phantom and clinical study. For phantom study, the measurement absorbed dose for a real time skin dosimeter was 3.0 mGy at the group A and 1.9 mGy at the group B (p

PURPOSE To compare the contrast enhancement between bolus-tracking (BT) and test-bolus (TB) methods in coronary computed tomography angiography (CCTA). METHOD We enrolled 300 patients who underwent CCTA by BT (245 mg I/kg main bolus) or TB (77.4 mg I/kg test bolus with 245 mg I/kg main bolus) methods. In group BT (n=150), scanning was started automatically 5-second after contrast enhancement exceeded a predefined threshold of 150 Hounsfield units (HU). In group TB (n=150), TB peak attenuation plus 2-second was used as a delay. We recorded the CT number in the ascending aorta and determined whether the CT number was equivalent in two groups. For the equivalence test, we adopted 70 HU as the equivalence margin. The standard deviation (SD) in the CT number and the rate of patients with an acceptable CT number were compared. We also compared total iodine dose and total dose length product (DLP). RESULT The CT number of the ascending aorta was 437.6±68.9 HU in group BT and 438.9±69.7 HU in group TB; the 95% confidence interval for the difference between the groups was from -11.6 to 20.2 HU and within the range of the equivalence margins. The SD of the CT number and the rate of patients with acceptable CT number did not differ significantly between the two groups (p=0.857 and p=0.614, respectively). Total iodine dose in group TB was significantly higher than in group BT (p

Background Arteriosclerosis may progress and lead to peripheral arterial disease (PAD) during the waiting period until kidney transplantation in end-stage kidney disease (ESKD) patients. Additionally, contrast-induced nephropathy (CIN) of a kidney allograft after the examination and treatment for PAD is problematic. Here, we report the case of a kidney transplant recipient with PAD in the lower extremities who underwent percutaneous transluminal angioplasty (PTA) with carbon dioxide to prevent CIN incidence. Case presentation A 57-year-old woman underwent a cadaveric kidney transplant when she was 49 years old. Immunosuppression was maintained with tacrolimus, methylprednisolone, and mycophenolate mofetil. Her post-transplant course was uneventful, and serum creatinine level was maintained at 1.1–1.3 mg/dL. Intermittent claudication of the lower legs began 3 years after transplantation. Under saline intravenous rehydration, computed tomographic angiographies were performed, and the patient was diagnosed with PAD in the bilateral lower extremities. Total PTA was performed thrice for PAD in the lower extremities via a combination of carbon dioxide and iodinated contrast medium to prevent CIN incidence at 3, 4, and 7 years after kidney transplantation. The patient’s recoveries were uneventful. One year later, the serum creatinine level was maintained at 0.9–1.1 mg/dL, and since then, the patient has shown no evidence of recurrence. Conclusions In a kidney transplant recipient with PAD, PTA with carbon dioxide was effective to minimize the volumes of iodinated contrast medium and prevent CIN incidence.

Introduction: Recurrent central venous restenosis is problematic in patients with ipsilateral arteriovenous fistula. We report our experience using a drug-eluting stent for the treatment of recurrent central vein restenosis. Case report: A 60-year-old man consulted our hospital because of recurrent swelling of his left upper limb with radial-cephalic arteriovenous fistula that originated in the distal forearm. More than 3 years prior, two bare-metal stents were placed for the obstructed lesions in the left subclavian and brachiocephalic venous lesions, and repeated balloon angioplasty for recurrent in-stent stenosis was performed approximately every 3 months. Angiography with iodinated contrast agents revealed an approximately 3-cm-long restenosis at the distal part of the bare-metal stents. One drug-eluting stent (Zilver PTX Drug-Eluting Peripheral Stent; Cook Medical, Bloomington, IN, USA) was deployed at the narrowing lesion, followed by balloon angioplasty. The stenotic lesion was successfully and safely dilated. The patient consulted our hospital 5.5 months after drug-eluting stent placement because of restenosis at the distal part of the drug-eluting stent, but only in a shorter segment than before. Freedom from clinically driven target-lesion revascularization (TLR) extended from 3.1 to 5.5 months after drug-eluting stent placement. Although additional implantation of the second drug-eluting stent was required 14.6 months after the first drug-eluting stent placement, freedom from TLR before/after the second drug-eluting stent placement extended from 4.4 months to more than 8.6 months. Conclusion: Drug-eluting stent placement is an effective strategy for recurrent central venous stenosis in patients with ipsilateral arteriovenous fistula. To our knowledge, this is the first report of drug-eluting stent placement for recurrent venous stenosis in a patient undergoing hemodialysis.

Strigolactones (SLs) are a class of plant hormones which regulate shoot branching and function as host recognition signals for symbionts and parasites in the rhizosphere. However, steps in SL biosynthesis after carlactone (CL) formation remain elusive. This study elucidated the common and diverse functions of MAX1 homologs which catalyze CL oxidation. We have reported previously that ArabidopsisMAX1 converts CL to carlactonoic acid (CLA), whereas a rice MAX1 homolog has been shown to catalyze the conversion of CL to 4-deoxyorobanchol (4DO). To determine which reaction is conserved in the plant kingdom, we investigated the enzymatic function of MAX1 homologs in Arabidopsis, rice, maize, tomato, poplar and Selaginella moellendorffii. The conversion of CL to CLA was found to be a common reaction catalyzed by MAX1 homologs, and MAX1s can be classified into three types: A1-type, converting CL to CLA; A2-type, converting CL to 4DO via CLA; and A3-type, converting CL to CLA and 4DO to orobanchol. CLA was detected in root exudates from poplar and Selaginella, but not ubiquitously in other plants examined in this study, suggesting its role as a species-specific signal in the rhizosphere. This study provides new insights into the roles of MAX1 in endogenous and rhizosphere signaling.

Objective To evaluate the effect of patient characteristics on popliteal aortic contrast enhancement at lower extremity CT angiography (LE-CTA) scanning. Materials and Methods Prior informed consent to participate was obtained from all 158 patients. All were examined using a routine protocol; the scanning parameters were tube voltage 100 kVp, tube current 100 mA to 770 mA (noise index 12), 0.5-second rotation, 1.25-mm detector row width, 0.516 beam pitch, and 41.2-mm table movement, and the contrast material was 85.0 mL. Cardiac output (CO) was measured with a portable electrical velocimeter within 5 minutes of starting the CT scan. To evaluate the effects of age, sex, body size, CO, and scan delay on the CT number of popliteal artery, the researchers used multivariate regression analysis. Results A significant positive correlation was seen between the CT number of the popliteal artery and the patient age (r = 0.39, p < 0.01). A significant inverse correlation was observed between the CT number of the popliteal artery and the height (r = -0.48), total body weight (r = -0.52), body mass index (r = -0.33), body surface area (BSA) (r = -0.56), lean body weight (r = -0.56), and CO (r = -0.35) (p < 0.001 for all). There was no significant correlation between the enhancement and the scan delay (r = 0.06, p = 0.47). The BSA, CO, and age had significant effects on the CT number (standardized regression: BSA -0.42, CO -0.22, age 0.15; p < 0.05, respectively). Conclusion The BSA, CO, and age are significantly correlated with the CT number of the popliteal artery on LE-CTA.

Severely calcified lesions continue to plague endovascular interventions by negatively affecting the acute and long-term results. A new technique was developed to allow balloon crossing or to treat persistent recoil. In the direct extravascular calcium interruption arterial procedure technique, an artery forceps is percutaneously introduced to modify the plaque after conventional techniques have failed. In this initial experience, the direct extravascular calcium interruption arterial procedure technique was successful as a bailout option in patients in whom balloon crossing was impossible or recoil was untreatable even with high-pressure balloons.

Objective The aim of this study was to compare the diagnostic performance of 100- and 120-kVp coronary computed tomography (CT) angiography (CCTA) scans for the identification of coronary plaque components. Methods We included 116 patients with coronary plaques who underwent CCTA and integrated backscatter intravascular ultrasound studies. On 100-kVp scans, we observed 24 fibrous and 24 fatty/fibrofatty plaques; on 120-kVp scans, we noted 27 fibrous and 41 fatty/fibrofatty plaques. We compared the fibrous and the fatty/fibrofatty plaques, the CT number of the coronary lumen, and the radiation dose on scans obtained at 100 and 120 kVp. We also compared the area under the receiver operating characteristic (ROC) curve of the coronary plaques on 100- and 120-kVp scans with their ROC curves on integrated backscatter intravascular ultrasound images. Results The mean CT numbers of fatty and fatty/fibrofatty plaques were 5.71 ± 36.5 and 76.6 ± 33.7 Hounsfield units (HU), respectively, on 100-kVp scans; on 120-kVp scans, they were 13.9 ± 29.4 and 54.5 ± 22.3 HU, respectively. The CT number of the coronary lumen was 323.1 ± 81.2 HU, and the radiation dose was 563.7 ± 81.2 mGy-cm on 100-kVp scans; these values were 279.3 ± 61.8 HU and 819.1 ± 115.1 mGy-cm on 120-kVp scans. The results of ROC curve analysis identified 30.5 HU as the optimal diagnostic cutoff value for 100-kVp scans (area under the curve = 0.93, 95% confidence interval = 0.87-0.99, sensitivity = 95.8%, specificity = 78.9%); for 120-kVp plaque images, the optimal cutoff was 37.4 HU (area under the curve = 0.87, 95% confidence interval = 0.79-0.96, sensitivity = 82.1%, specificity = 85.7%). Conclusions For the discrimination of coronary plaque components, the diagnostic performance of 100- and 120-kVp CCTA scans is comparable.

PURPOSE To evaluate the image quality and effect of radiation dose reduction by setting for computed tomography automatic exposure control system (CT-AEC) in computed tomographic angiography (CTA) of lower extremity artery. METHODS Two methods of setting were compared for CT-AEC [conventional and contrast-to-noise ratio (CNR) methods]. Conventional method was set noise index (NI): 14and tube current threshold: 10-750 mA. CNR method was set NI: 18, minimum tube current: (X+Y)/2 mA (X, Y: maximum X (Y)-axis tube current value of leg in NI: 14), and maximum tube current: 750 mA. The image quality was evaluated by CNR, and radiation dose reduction was evaluated by dose-length-product (DLP). RESULTS In conventional method, mean CNRs for pelvis, femur, and leg were 19.9±4.8, 20.4±5.4, and 16.2±4.3, respectively. There was a significant difference between the CNRs of pelvis and leg (P

To investigate the anatomical features related to the failure of cryoballoon (CB) ablation for atrial fibrillation (AF) on pre-procedural CT images.We retrospectively analyzed CT images of 100 patients with AF who had undergone a first CB ablation at our institution between June 2016 and April 2017. We measured the angle, short- and long axis length, and the area and ovality of 4 major pulmonary vein (PV) ostium on CT images. We performed logistic regression analysis to analyze the anatomical features related to the failure (incomplete CB ablation) of PV isolation. We also performed a receiver-operating characteristic (ROC) curve analysis to identify an appropriate cut-off value for anatomical features significantly associated with incomplete CB ablation.We analyzed 400 PVs in 100 patients [aged 64 (range, 27-82) years, 59% male]. The rate of incomplete CB ablation was significantly higher for right-than left-sided PVs (p 0.001). The anatomical feature significantly associated with incomplete CB ablation was the angle at the right inferior PV (RIPV) (AOR: 1.17; 95% CI: 1.09-1.27, p 0.001) and the right superior PV (RSPV) (AOR: 1.12; 95% CI: 1.01-1.23; p = 0.014). In the ROC analysis, the optimal cut-off value for RIPV and RSPV angle to discriminate an incomplete CB ablation were 40.1° and 79.7°, respectively.Our findings may help to select the appropriate ablation strategy to treat patients with AF. We show that the angle is an anatomical feature significantly related to failed CB ablation.

To investigate the clinical utility of our newly developed contrast enhancement optimizer (CEO) software for coronary CT angiography (CCTA). We randomly assigned 295 patients (168 males, 127 females, median age 71 years) undergoing CCTA to one of two contrast media injection protocols. Group A (n = 150) was injected with a CEO-selected iodine dose based on patient factors. In group B (n = 145), we used our standard protocol (245 mg I/kg). We recorded the CT number in the ascending aorta and determined whether the CT number was equivalent in groups A and B. For the equivalence test, we adopted 75 Hounsfield units (HU) as the equivalence margin. The standard deviation in the CT number and the rate of patients with an acceptable CT number were compared using the F test and the chi-square test, respectively. The iodine dose in group A was significantly smaller than that in group B (235.7 vs. 253.6 mg I/kg, p

The aim of the present study was to develop an automated system for determining the cardiac rest period during whole-heart coronary magnetic resonance angiography (CMRA) examination.Ten healthy male volunteers (25-51 years old, 50-77 beats/min heart rate) were enrolled in this prospective study. A motion area map was generated from a cine image set by extracting high-speed component of cardiac motion, and it was used to specify the rest period in the proposed CMRA. In conventional CMRA, the rest period was determined based on the visual inspection of cine images. Agreement of the start time, end time, and trigger time between the two methods was assessed by the Bland-Altman plot analysis. Two observers visually evaluated the quality of the curved planar reformation (CPR) image of the coronary arteries.The proposed method significantly prolonged the start time (mean systematic difference 37.7 ms, P 0.05) compared with the conventional method. Good agreement was observed for the end time (mean systematic difference 8.9 ms) and trigger time (mean systematic difference -28.8 ms) between the two methods. A significantly higher image quality (P 0.05) was provided for the left circumflex artery in the proposed CMRA (mean grading score 3.88) than in conventional CMRA (mean grading score 3.68).Our system enabled detection of the rest period automatically without operator intervention and demonstrated somewhat higher image quality compared with conventional CMRA. Its use may be useful to improve the imaging workflow for CMRA in clinical practice.

The purpose of our study was to compare test bolus techniques using undiluted or diluted contrast material for their ability to predict aortic enhancement on coronary computed tomographic angiography (c-CTA) images.We divided 200 consecutive patients who underwent c-CTA on a 64-MDCT scanner into two groups. In group A (n = 100), we used a test bolus of undiluted contrast material and in group B (n = 100), the contrast material was diluted. The injection volume was body weight × 0.2 (contrast material 100%) in group A and body weight × 0.7 (contrast material 30%, saline 70%) in group B. We then compared the CT number in the ascending aorta on c-CTA images obtained with undiluted and diluted contrast media to the CT number on c-CTA images.The mean CT number in the ascending aorta was significantly higher in group B than group A (217.1 vs. 157.4 HU, P .001). There was a significant difference in the correlation between the CT number of the ascending aorta on c-CTA images and on images acquired with the test bolus using undiluted or diluted test bolus (P .001). In group B, the correlation had a strong positive linear relationship (r = 0.72, P .001), whereas in group A the positive linear relationship was weak (r = 0.36).The test bolus with diluted contrast material was useful for predicting aortic enhancement before c-CTA scanning.

Introduction The aim of this study was to evaluate the radiation dose and image quality at low tube-voltage pediatric chest computed tomographic angiography (CTA) that applies the same contrast-to-noise ratio (CNR) index as the standard tube voltage technique. Materials and Methods Contrast-enhanced chest CTA scans of 100 infants were acquired on a 64-row multidetector computed tomography (MDCT) scanner. In the retrospective study, we evaluated 50 images acquired at 120 kVp; the image noise level was set at 25 Hounsfield units. In the prospective study, we used an 80-kVp protocol; the image noise level was 40 Hounsfield units because the iodine contrast was 1.6 times higher than on 120-kVp scans; the CNR was as in the 120-kVp protocol. We compared the CT number, image noise, CT dose index volume (CTDIvol), and the dose-length product on scans acquired with the 2 protocols. A diagnostic radiologist and a pediatric cardiologist visually evaluated all CTA images. Results The mean CTDIvol and the mean dose-length product were 0.5 mGy and 7.8 mGy-cm for 80- and 1.2 mGy and 20.8 mGy-cm for 120-kVp scans, respectively ( P < .001). The mean CTDIvol was 42% lower at 80 kVp than at 120 kVp, and there was no significant difference in the visual scores assigned to the CTA images ( P = .28). Conclusions With the CNR index being the same at 80-kVp and 120-kVp imaging, the radiation dose delivered to infants subjected to chest CTA can be reduced without degradation of the image quality.

The objective of our study was to compare contrast enhancement on CT angiography (CTA) images of the lower extremity in patients with suspected peripheral artery disease who did not undergo hemodialysis (HD) and patients who were scanned before or after HD.We divided 287 consecutive patients who underwent CTA of the lower extremity on a 64-MDCT scanner into three groups: group 1 patients (n = 151) were not dependent on HD, group 2 patients (n = 70) were dependent on HD and underwent HD less than 24 hours after CTA, and group 3 (n = 66) were dependent on HD and underwent HD less than 24 hours before CTA. We then compared the CT number in the popliteal artery at the level of the patella on all CTA images. A cardiologist and a radiology technologist visually evaluated the depiction of the descending genicular artery (DGA) on the CTA images and assigned a visualization score.The median CT number was lowest in group 2 patients (373 HU vs 429 [group 1] and 418 [group 3] HU). The score for visualization of the DGA was significantly lower in group 2 than in group 1 (p = 0.02) and group 3 (p = 0.04).At CTA, arterial enhancement decreases with the passage of time after HD likely because of the increase in intravascular volume. CTA that is performed within 24 hours after HD generates higher-quality images of the lower extremities than CTA that is performed within 24 hours before HD.

Purpose Increased vascular access flow after percutaneous transluminal angioplasty (PTA) for central venous stenosis and occlusion (central venous disease, CVD) can affect cardiac function in hemodialysis (HD) patients. We evaluated the cardiac function, etiology, and treatment in HD patients with CVD. Methods HD patients with CVD treated by PTA between June 2006 and February 2013 were studied. Results Of the 26 patients, 22 had left arteriovenous fistulas (AVFs), 1 left arteriovenous graft (AVG), 2 right AVFs, and 1 right AVG. CVD sites were the left brachiocephalic vein (LBCV; n=13), left subclavian vein (LSCV; n=7), both LBCV and LSCV (n=3), right BCV (n=2), and right SCV (n=1). Computed tomography findings indicated a high extrinsic compression rate for the LBCV (91%) and LSCV (50%). The success rate of PTA was 96%. The primary patency rates at 3, 6, 9, and 12 months were 81%, 73%, 65%, and 57%, respectively. The post-PTA brachial artery flow volume was significantly increased compared with the pre-PTA volume (1306 vs. 957 ml/min; p=0.005). The post-PTA left ventricular ejection fraction and expiration inferior vena cava diameter were the same as the pre-PTA values (57% versus 60%, p=0.2 and 17 versus 17 mm, p=0.9, respectively). Conclusions Our findings suggest that increased vascular access flow after PTA for CVD has no relation to cardiac function.

Purpose To assess the probability of achieving optimal contrast enhancement in 100 kVp and 120 kVp-protocol on hepatic computed tomography (CT) scans. Materials and methods We enrolled 200 patients in a retrospective cohort study. Hundred patients were scanned with 120 kVp setting, and other 100 patients were scanned with 100 kVp setting. We measured the CT number in the abdominal aorta and hepatic parenchyma on unenhanced scans and hepatic arterial phase (HAP)-, and portal venous phase (PVP). The aortic enhancement at HAP and the hepatic parenchymal enhancement at PVP were compared between the two scanning protocols. Bayesian inference was used to assess the probability of achieving optimal contrast enhancement in each protocol. Results The Bayesian analysis indicated that when 100 kVp-rotocol was used, the probability of achieving optimal aortic enhancement (>280 HU) was 98.8% ± 0.6%, whereas it was 88.7% ± 2.5% when 120 kVp-protocol was used. Also, the probability of achieving optimal hepatic parenchymal enhancement (>50 HU) was 95.3% ± 1.5%, whereas it was 64.7% ± 3.8% when 120 kVp-protocol was used. Conclusion Bayesian inference suggested that the post-test probability of optimal contrast enhancement at hepatic dynamic CT was lower under the 120 kVp than the 100 kVp-protocol.

OBJECTIVE: To compare the ability of test scans with undiluted and diluted contrast medium (CM) to predict contrast enhancement (CE) on cardiovascular CT angiography (CCTA) images of infants. METHODS: We divided 120 consecutive infants who had undergone CCTA on a 64-MDCT scanner into two equal groups. In one group, the test bolus consisted of undiluted CM [protocol 1 (P1): injection volume = total body weight × 1.2 ml, injection time 5 s], in the other (P2) it was total body weight × 4.0 ml (CM 15%, saline 85%, injection time 16 s). CE on the test scans was recorded on a 3-point visual scale. We investigated the relation for CE in the pulmonary artery and ascending aorta between the P1 or P2 test scans and CCTA images. RESULTS: While peak CE was observed on all test scans performed with P2, in approximately 10 % of test scans obtained under P1, peak CE was not visualized. There was a strong positive linear correlation for CE of the pulmonary artery and ascending aorta on P2 images (r = 0.61 and r = 0.63, p < 0.01); under P1 the correlation was weak (r = 0.26 and r = 0.33, p < 0.01). CONCLUSION: Test-scanning with diluted CM revealed the optimal CE peak time and was useful for predicting CE on CCTA scans of the pulmonary artery and ascending aorta in infants with congenital heart disease. ADVANCES IN KNOWLEDGE: Diluted test scans help to select the optimal scan parameters for the CCTA study of infants by using contrast-to-noise-based scanning.

The incidence of acute nonvariceal massive gastrointestinal bleeding (GIB) is higher in hemodialysis (HD) patients than in healthy individuals, and this is often a life-threatening event. We evaluated the efficacy of intra-arterial treatment for GIB in HD patients. Between January 2006 and June 2012, eight HD patients with GIB were treated with superselective transarterial embolization. Of the eight cases, one was duodenal bleeding, two were jejunal bleeding, one was ileocecum bleeding, two were ascending colonic bleeding, and two were sigmoid colonic bleeding. After examining the site of bleeding by endoscopy or contrast-enhanced computed tomography (CT), embolizations with microcoils, gelatin sponges, or N-butyl cyanoacrylate were performed through interventional radiology (IVR). In all cases, blood transfusions were frequently administered. Six of the eight patients with GIB were successfully salvaged by transarterial embolization. In one case, duodenal bleeding was refractory to endoscopic treatment. Embolization was performed twice in this case; however, the patient died of an aneurysm rupture at the embolization site 24 days after the embolizations. In another case, massive jejunal bleeding and disseminated intravascular coagulation were identified at the time of the first examination, and the patient died of multiorgan failure 26 days after the embolization. On the basis of our experience, we established an effective treatment strategy for HD patients with acute nonvariceal massive GIB, by immediately identifying the exact site and degree of bleeding using contrast-enhanced computed tomography and performing early treatment with transarterial embolization.

PURPOSE Massive calcification complicates the diagnosis of the blood vessel lumen in computed tomography angiography (CTA) of the arteries of the lower extremities. The purpose of this study was to evaluate subtraction CTA with the use of orbital synchronized helical scanning (OS-SCTA). METHOD Phantom study: We performed OS-SCTA and non-OSCTA of a calcified vessel phantom (ψ2.5 mm), and compared them with a non-calcified vessel phantom as the reference by full width at half maximum (FWHM) and full width at tenth maximum (FWTM) of maximum intensity projection (MIP) images. Clinical study: 58 patients with peripheral artery disease who were referred for angiography also underwent OS-SCTA. OS-SCTA was produced using MIP images. Findings were graded according to three categories: (1) stenosis greater than 50% or occluded; (2) stenosis less than 50%; (3) not detected due to insufficient image quality. OS-SCTA findings were compared with the angiographic findings for each arterial segment. RESULTS In the phantom study, FWHM showed no significant difference between OS-SCTA and the reference (P=0.135), whereas FWTM showed a significant difference (P

OBJECTIVE We evaluated the effect of the age, sex, total body weight (TBW), height (HT) and cardiac output (CO) of patients on aortic and hepatic contrast enhancement during hepatic-arterial phase (HAP) and portal venous phase (PVP) computed tomography (CT) scanning. METHODS This prospective study received institutional review board approval; prior informed consent to participate was obtained from all 168 patients. All were examined using our routine protocol; the contrast material was 600 mg/kg iodine. Cardiac output was measured with a portable electrical velocimeter within 5 minutes of starting the CT scan. We calculated contrast enhancement (per gram of iodine: [INCREMENT]HU/gI) of the abdominal aorta during the HAP and of the liver parenchyma during the PVP. We performed univariate and multivariate linear regression analysis between all patient characteristics and the [INCREMENT]HU/gI of aortic- and liver parenchymal enhancement. RESULTS Univariate linear regression analysis demonstrated statistically significant correlations between the [INCREMENT]HU/gI and the age, sex, TBW, HT, and CO (all P < 0.001). However, multivariate linear regression analysis showed that only the TBW and CO were of independent predictive value (P < 0.001). Also, only the CO was independently and negatively related to aortic enhancement during HAP and to liver parenchymal enhancement when the contrast material injection protocol was adjusted for the TBW (P < 0.001). CONCLUSION By multivariate linear regression analysis only the TBW and CO were significantly correlated with aortic and liver parenchymal enhancement; the age, sex, and HT were not. The CO was the only independent factor affecting aortic and liver parenchymal enhancement at hepatic CT when the protocol was adjusted for the TBW.

PURPOSE The purpose of this study was to investigate the association of vessel visibility and radiation dose using contrast-to-noise ratio (CNR) method with low tube voltage in coronary computed tomography angiography (c-CTA). METHODS We performed electrocardiogram-gated scan of 2.0-mm diameter simulated vessel in the center of the cardiac phantom by the use of a 64-detector CT scanner. Reference CNR was calculated from the target coronary CT number (CTnumberA; 350 Hounsfield units [HU]), epicardial fat CT number (CTnumberB; -100 HU), and target epicardial fat standard deviation (SD) number (SDB; 25 HU) at the 120 kV. We obtained the tube current at low tube voltage (100 and 80 kV) to perform the similar reference CNR at 120 kV. The full widths at half maximum from axial images were evaluated with quantitative evaluation and three types of visualizations of the vessel phantom were evaluated with the qualitative evaluations. RESULTS CTnumberA of 100 and 80 kV were increased by 26% and 50%, respectively, compared with 120 kV (P 0.05). CONCLUSION In this phantom study, these results show that the CNR method with low tube voltage achieves radiation dose reduction without decreasing the image quality.

Two new species, Paraulopus longianalis n.sp. and Paraulopus melanostomus n.sp., are described from western and southern Australian waters. Both are referable to the Paraulopus nigripinnis group of Sato and Nakabo (2002b, 2003) in having 4.5–5.5 scales above the lateral line, supraocular ridges and large adult body size, but differ from other species of the group in having two rows of cheek scales. Paraulopus longianalis is characterized by a deep anal fin in males, tiny adipose dorsal fin and supraocular ridges extending nearly to the predorsal scales, and P. melanostomus is most easily distinguished by its black buccal cavity and relatively broad, depressed head. A key to the six described species in the P. nigripinnis group is provided.

Objective We evaluated the effect of various patient characteristics and time-density curve (TDC)-factors on the test bolus-affected vessel enhancement on coronary computed tomography angiography (CCTA). We also assessed the value of generalized linear regression models (GLMs) for predicting enhancement on CCTA. Materials and Methods We performed univariate and multivariate regression analysis to evaluate the effect of patient characteristics and to compare contrast enhancement per gram of iodine on test bolus (ΔHUTEST) and CCTA (ΔHUCCTA). We developed GLMs to predict ΔHUCCTA. GLMs including independent variables were validated with 6-fold cross-validation using the correlation coefficient and Bland–Altman analysis. Results In multivariate analysis, only total body weight (TBW) and ΔHUTEST maintained their independent predictive value (p < 0.001). In validation analysis, the highest correlation coefficient between ΔHUCCTA and the prediction values was seen in the GLM (r = 0.75), followed by TDC (r = 0.69) and TBW (r = 0.62). The lowest Bland–Altman limit of agreement was observed with GLM-3 (mean difference, −0.0 ± 5.1 Hounsfield units/grams of iodine [HU/gI]; 95% confidence interval [CI], −10.1, 10.1), followed by ΔHUCCTA (−0.0 ± 5.9 HU/gI; 95% CI, −11.9, 11.9) and TBW (1.1 ± 6.2 HU/gI; 95% CI, −11.2, 13.4). Conclusion We demonstrated that the patient's TBW and ΔHUTEST significantly affected contrast enhancement on CCTA images and that the combined use of clinical information and test bolus results is useful for predicting aortic enhancement.

Rationale and objectives We delivered the saline chaser via a spiral flow-generating tube or a conventional connecting tube and compared arterial enhancement at computed tomography angiography (CTA) of the lower extremities. Materials and methods We randomly assigned 100 patients whose ankle bronchial pressure index or clinical symptoms were suspect of peripheral arterial disease to a spiral flow-generating tube (protocol A) or a conventional connecting-tube protocol (protocol B) and performed CTA of the lower extremities. The test bolus was delivered under protocol A or B, and the CT numbers recorded for each protocol were compared. Two radiological technologists visually evaluated the descending genicular artery. Results In the test injection, the median CT number for the popliteal artery was significantly higher with protocol A than B (204.5 HU vs. 170.5 HU, P = 0.03). For CTA of the lower extremities, the median CT number for the popliteal artery at the level of the patella was 436.1 HU (range, 259-608 HU) under protocol A; with protocol B, it was 382.9 HU (range, 244-564 HU) (P = 0.02). The visual score assigned in the descending genicular artery was statistically significantly higher under protocol A than B (P = 0.03). Conclusions Use of the spiral flow-generating tube increased the effect of the saline chaser and significantly improved arterial enhancement from the abdominal aorta to the arteries of the foot at CTA of the lower extremities.