Impact of genetic and non-genetic factors on phenotypic diversity in NBAS-associated disease.

Biallelic pathogenic variants in neuroblastoma-amplified sequence (NBAS) cause a pleiotropic multisystem disorder. Three clinical subgroups have been defined correlating with the localisation of pathogenic variants in the NBAS gene: variants affecting the C-terminal region of NBAS result in SOPH syndrome (short stature, optic atrophy, Pelger-Huët anomaly), variants affecting the Sec 39 domain are associated with infantile liver failure syndrome type 2 (ILFS2) and variants affecting the ß-propeller domain give rise to a combined phenotype. However, there is still unexplained phenotypic diversity across the three subgroups, challenging the current concept of genotype-phenotype correlations in NBAS-associated disease. Therefore, besides examining the genetic influence, we aim to elucidate the potential impact of pre-symptomatic diagnosis, emergency management and other modifying variables on the clinical phenotype. We investigated genotype-phenotype correlations in individuals sharing the same genotypes (n = 30 individuals), and in those sharing the same missense variants with a loss-of-function variant in trans (n = 38 individuals). Effects of a pre-symptomatic diagnosis and emergency management on the severity of acute liver failure (ALF) episodes also were analysed, comparing liver function tests (ALAT, ASAT, INR) and mortality. A strong genotype-phenotype correlation was demonstrated in individuals sharing the same genotype; this was especially true for the ILFS2 subgroup. Genotype-phenotype correlation in patients sharing only one missense variant was still high, though at a lower level. Pre-symptomatic diagnosis in combination with an emergency management protocol leads to a trend of reduced severity of ALF. High genetic impact on clinical phenotype in NBAS-associated disease facilitates monitoring and management of affected patients sharing the same genotype. Pre-symptomatic diagnosis and an emergency management protocol do not prevent ALF but may reduce its clinical severity.

Difference in urinary protein-to-creatinine ratio using the benzethonium chloride and pyrogallol red methods in children.

BACKGROUND: The appropriate reference value of the urinary protein-to-creatinine ratio (PCR) for proteinuria may change when the urinary pyrogallol red (PR) protein assay method is changed to the benzethonium chloride method (BC). This study aimed to evaluate the difference between BC-based PCR (BC-PCR) and PR-based PCR (PR-PCR) values in children. METHODS: We compared the BC-PCR and PR-PCR values in the same first-morning urine samples without significant proteinuria in school urine screening settings. The upper limit of the reference values was set at the 97.5th percentile. RESULTS: Notably, 133 samples from 124 individuals (female: 62%, age: median 12.3 years, range 6.3-16.9 years) were collected between August 2020 and October 2022. The diagnoses included 34 normal individuals and 99 with asymptomatic hematuria. The urinary protein (UP) concentrations measured using the BC (BC-UP) and PR (PR-UP) methods were in a linear relationship; however, the BC-UP concentrations were higher than the PR-UP concentrations (mean of differences: 11.2, 95% confidence interval (CI): 11.0-13.4 mg/dL). Also, the BC-PCR values were higher than the PR-PCR values (mean of differences: 0.090, 95% CI: 0.082-0.098 g/gCr). The BC-PCR showed a body-size-related decrease, reflecting a body-size-related urinary creatinine increase. The suggested BC-PCR reference values for proteinuria were 0.25 and 0.17 g/gCr for elementary (6-12.4 years) and junior high school students (12.5-16 years), respectively. These values were higher than those of the PR-PCR and need further studies. CONCLUSIONS: When evaluating PCR results, the urinary protein assay should be stated.

In Vitro Study of the Precision and Accuracy of Measurement of the Vascular Inner Diameter on Computed Tomography Angiography Using Deep Learning Image Reconstruction: Comparison With Filtered Back Projection and Iterative Reconstruction.

OBJECTIVE: This study aimed to compare the performance of deep learning image reconstruction (DLIR) with that of standard filtered back projection (FBP) and adaptive statistical iterative reconstruction V (ASiR-V) for measurement of the vascular diameter on computed tomography (CT) angiography model. METHODS: We used 6 vascular models of 3 wall thicknesses. We used DLIR, FBP, and ASiR-V for reconstruction, and compared the accuracy and precision of vascular diameter measurement, as well as the image noise, among the 3 reconstruction methods. RESULTS: Image noise was in the order of FBP > ASiR-V > DLIR. The vascular diameters measured using DLIR and ASiR-V were comparable with, or significantly closer to, the actual diameter than those measured using FBP. The precision of the diameter measurement using DLIR was comparable with or significantly superior to that using FBP/ASiR-V. CONCLUSIONS: Use of DLIR, as compared with FBP or ASiR-V, for image reconstruction can improve the precision and accuracy of vascular diameter measurement.

Evaluation of Spatial Resolution of Virtual Monochromatic Imaging In Vitro: Effect of Energy Level and Contrast.

OBJECTIVE: Our aim was to evaluate effects of the energy level and contrast on the spatial resolution of virtual monochromatic imaging (VMI). METHODS: With 2 types of computed tomographic (CT) scanners (Discovery CT750 HD and Revolution CT), we scanned an elliptical cylinder acrylic phantom with 20- or 40-fold dilutions of contrast medium and obtained VMI data sets at 40, 50, 60, and 70 keV. We evaluated the effects of energy levels and contrast on modulation transfer function (MTF) and the effect of energy levels on noise power spectra (NPS). RESULTS: With both CT scanners, MTF decreased significantly as the energy level decreased. The effect of the dilution of contrast media on MTF varied with CT scanners. With both scanners, NPS curves demonstrate uniform increase in NPS across the entire spatial frequency as the energy levels decreased. CONCLUSIONS: The energy level and contrast can affect the spatial resolution of VMIs.

Comparison of full-iodine conventional CT and half-iodine virtual monochromatic imaging: advantages and disadvantages.

PURPOSE: To compare image quality of abdominal arteries between full-iodine-dose conventional CT and half-iodine-dose virtual monochromatic imaging (VMI). MATERIALS AND METHODS: We retrospectively evaluated images of 21 patients (10 men, 11 women; mean age, 73.9 years) who underwent both full-iodine (600 mg/kg) conventional CT and half-iodine (300 mg/kg) VMI. For each patient, we measured and compared CT attenuation and the contrast-to-noise ratio (CNR) of the aorta, celiac artery, and superior mesenteric artery (SMA). We also compared CT dose index (CTDI). Two board-certified diagnostic radiologists evaluated visualisation of the main trunks and branches of the celiac artery and SMA in maximum-intensity-projection images. We evaluated spatial resolution of the two scans using an acrylic phantom. RESULTS: The two scans demonstrated no significant difference in CT attenuation of the aorta, celiac artery, and SMA, but CNRs of the aorta and celiac artery were significantly higher in VMI (p = 0.011 and 0.030, respectively). CTDI was significantly higher in VMI (p = 0.024). There was no significant difference in visualisation of the main trunk of the celiac artery and SMA, but visualisation of the gastroduodenal artery, pancreatic arcade, branch of the SMA, marginal arteries, and vasa recta was significantly better in the conventional scan (p < 0.001). The calculated modular transfer function (MTF) suggested decreased spatial resolution of the half-iodine VMI. CONCLUSION: Large-vessel depiction and CNRs were comparable between full-iodine conventional CT and half-iodine VMI images, but VMI did not permit clear visualisation of small arteries and required a larger radiation dose. KEY POINTS: ・Reducing the dose of iodine contrast medium is essential for chronic kidney disease patients to prevent contrast-induced nephropathy. ・In virtual monochromatic images at low keV, contrast of relatively large vessels is maintained even with reduced iodine load, but visibility of small vessels is impaired with decreased spatial resolution. ・We should be aware about the advantages and disadvantages associated with virtual monochromatic imaging with reduced iodine dose.

Comparison of Motion Artifacts on CT Images Obtained in the Ultrafast Scan Mode and Conventional Scan Mode for Unconscious Patients in the Emergency Department.

OBJECTIVE. The purpose of this study was to investigate whether, in the evaluation of unconscious patients in the emergency department, a new-generation CT scanner that acquires images in ultrafast scan mode (large coverage, fast rotation, high helical pitch) would reduce motion artifacts on whole-body CT images in comparison with those on images obtained with a conventional CT scanner. MATERIALS AND METHODS. Images of a total of 60 unconscious patients presenting to the emergency department were evaluated retrospectively. Of the 60 patients, 30 underwent CT with a new-generation scanner that acquires images in the ultrafast mode, and 30 underwent CT with a conventional scanner. Two radiologists independently evaluated motion artifacts in the aorta, lung, diaphragm, liver, and kidneys. The motion artifacts were graded in severity on a 4-point scale. A value of p < 0.05 was considered to indicate a statistically significant difference. RESULTS. Interobserver agreement on motion artifact ratings was good (κ = 0.80-0.93). Images obtained with the new-generation CT scanner showed a significant reduction in motion artifacts in the aortic root (p = 0.0003), lower lungs (p = 0.011), diaphragm (p = 0.0047), liver (p = 0.0026), and kidneys (p = 0.019). However, there were no significant differences between the two groups with respect to motion artifacts of the aortic arch, thoracic descending aorta, abdominal aorta, and upper lungs. CONCLUSION. CT images obtained in the ultrafast scan mode in the evaluation of unconscious patients had a significant reduction in motion artifacts. The ultrafast technique is expected to be useful for diagnostic CT in the emergency department.

Treatment outcomes and prognostic factors of medication-related osteonecrosis of the jaw: a case- and literature-based review.

OBJECTIVES: The purpose of this study was to investigate the treatment outcomes and prognostic factors of medication-related osteonecrosis of the jaw (MRONJ) in Japanese patients. PATIENTS AND METHODS: Among 409 cases, treatment outcomes and prognostic factors were investigated in 275 patients. In statistical analyses, the 1-year cumulative curative rate was calculated with the Kaplan-Meier method, and significance was examined with the Wilcoxon test. Cox's proportional hazards regression analysis was used for the multivariate analysis. RESULTS: Resolution of the disease was achieved in 137 out of 275 MRONJ patients (49.8%). One-year cumulative curative rates were 39.8% in stage 1 patients, 26.3% in stage 2, and 19.0% in stage 3. The 1-year cumulative curative rates of treatment interventions were 17.2% for conservative treatment, 34.5% for sequestrectomy, and 40.7% for extended surgery including bone resection and segmental resection. As the prognostic factors of treatment outcomes, the type of medication, stage of MRONJ, and type of surgical intervention were identified as independent factors in a multivariate analysis. CONCLUSION: These results suggest that surgical interventions may lead to a good prognosis in MRONJ patients. CLINICAL RELEVANCE: This study indicated that surgical intervention for MRONJ might lead to improvement of prognosis and quality of life in MRONJ patients.

Ultrashort-Segment Embolization of High-Flow Vessels Using a Coil Packing Technique in an Amplatzer Vascular Plug.

PURPOSE: To report an experimental study and clinical case using a coil packing technique that hastens occlusion of an Amplatzer Vascular Plug 1 (AVP1) in short-segment embolization of high-flow target vessels. TECHNIQUE: An experimental vascular stenosis model was made of 12-mm soft polyvinyl chloride tubing. Under continuous pulsatile flow, a 12-mm AVP1 was deployed in the 4-mm-diameter stenosis. Before detachment of the AVP1, a 2.2-F microcatheter was inserted into the AVP1 through its mesh via a 6-F delivery guiding sheath in parallel with the delivery wire. Hydrogel microcoils were deployed tightly in the AVP1 and the plug was detached. After the procedure, the pulsatile saline flow was nearly obliterated. In the first clinical case, a 64-year-old man with a thoracic aortic stent-graft and single vessel debranching for type B aortic dissection developed a residual type II endoleak via the left subclavian artery. This coil packing technique in an AVP1 was employed to successfully embolize the leak. CONCLUSION: Based on the experimental study and the first experience in vivo, tight coil packing of an AVP1 might be a robust technique for ultrashort-segment embolization.

Preliminary Results: Can Dual-Energy Computed Tomography Help Distinguish Cardiogenic Pulmonary Edema and Acute Interstitial Lung Disease?

OBJECTIVE: We compared iodine concentration in pulmonary ground-glass opacity on iodine density images of contrast-enhanced chest dual-energy computed tomography (DECT) between patients with cardiogenic pulmonary edema (CPE) and acute interstitial lung disease (AILD). METHODS: Five of 12 patients who underwent contrast-enhanced chest DECT to exclude pulmonary embolism were clinically diagnosed with CPE and 7, with AILD. We compared the mean CT value on monochromatic images at 65 keV and iodine concentration on iodine density images between the affected and normal areas. RESULTS: The mean iodine concentrations were comparable between the affected and normal areas (P = 0.3048) in patients with CPE and were significantly higher in the affected than in the normal areas in those with AILD (P < 0.0001). CONCLUSIONS: Measurement of iodine concentration in pulmonary ground-glass opacity of contrast-enhanced chest DECT has the potential to help distinguish CPE and AILD.

Measurement of Vascular Diameter in Computed Tomography Angiography With Reduced Iodine Load: Comparison of Virtual Monochromatic Imaging in Dual-Energy Computed Tomography and Conventional Polychromatic Scan In Vitro.

OBJECTIVES: The aim of this study was to compare accuracy of measurement between virtual monochromatic imaging (VMI) in dual-energy computed tomography and conventional polychromatic 120-kVp computed tomographic scan in vascular models containing various densities of contrast material. METHODS: We evaluated measured diameters of 12 models of vessels of 4 inner diameters containing high, intermediate, and low densities of contrast material using software automation. RESULTS: Measurement errors with 70-keV VMI were significantly larger than or comparable to errors with 120-kVp scan for all models, and those with 50-keV VMI were significantly smaller than errors with 120-kVp scan for low-density models and larger for high-density models. CONCLUSIONS: Acquisition of images by VMI at low energy facilitates accurate measurement of diameters of poorly enhanced vessels with reduced iodine load but can increase measurement errors in other situations by decreasing spatial resolution, so VMI should be applied carefully to evaluate vessel diameter.

Glycemic control indicator levels at diagnosis of neonatal diabetes mellitus: Comparison with other types of insulin-dependent diabetes mellitus.

BACKGROUND: Neonatal diabetes mellitus (NDM) is a monogenic insulin-dependent diabetes that develops within 6 months of age. The progression of hyperglycemia until diagnosis is unknown. Glycemic control indicators at diagnosis are useful to estimate the extent and duration of hyperglycemia. We recently established that age-adjusted glycated albumin (GA) is a useful indicator of glycemic control, regardless of age. OBJECTIVE: To compare the levels of various glycemic control indicators at diagnosis between NDM and other types of insulin-dependent diabetes mellitus. PATIENTS AND METHODS: We included 8 patients with NDM, 8 with fulminant type 1 diabetes (FT1D), and 24 with acute-onset autoimmune type 1 diabetes (T1AD). Plasma glucose, glycated hemoglobin (HbA1c), GA, and age-adjusted GA (calculated as previously reported) were measured and compared. RESULTS: There were no significant differences in the plasma glucose levels of the group of patients with NDM and those with FT1D or T1AD. HbA1c and GA levels in the NDM group were not significantly different from those in the FT1D group, and both indicators were lower than those in the T1AD group. Age-adjusted GA levels in the NDM group did not differ significantly from those in the T1AD group, but were higher than those in the FT1D group. CONCLUSIONS: These findings suggest that the time-course of plasma glucose elevation in NDM until diagnosis is similar to that in T1AD. In addition, the high age-adjusted GA value at diagnosis of NDM indicates that this test is useful for assessing chronic hyperglycemia in NDM.

Preoperative urinary tract obstruction in scoliosis patients.

BACKGROUND: While the association between scoliosis and cardiac and respiratory function impairments has been well characterized in clinical practice and research, the potential effect of scoliosis on urinary tract structure and renal function has received little attention. Therefore, the purpose of this study was to evaluate the preoperative clinical characteristics of urinary tract structure and renal function in pediatric patients with idiopathic scoliosis, using a combination of blood tests, urinalysis, and imaging. METHODS: Preoperative measures of urinary tract structure and renal function were obtained for 16 patients, 13-17 years old, scheduled for corrective surgery for idiopathic scoliosis. Preoperative assessment included blood test and urinalysis, combined with structural imaging on ultrasound (US), magnetic resonance imaging (MRI), magnetic resonance urography (MRU), and radioisotope tracing (RI), using technetium-99 m mercaptoacetyltriglycine (99m Tc-MAG3). Differences in blood and urine tests between patients with and without urinary tract obstruction (UTO) were evaluated for significance using Mann-Whitney U test. RESULTS: For all 16 patients, blood tests and MRU were within normal limits. Dilatation of the renal pelvis was identified on US in eight patients (50.0%). UTO was identified on RI in six patients (37.5%). UTO was associated with elevated ß2-microglobulin concentration. Urinary ß2-microglobulin concentration >0.7 µg/mg Cr differentiated patients with UTO from those without UTO, with a sensitivity of 100% and specificity of 70%. CONCLUSIONS: ß2-Microglobulin concentration may be a useful marker to screen for asymptomatic UTO in patients with idiopathic scoliosis.

Effects of molecular weight and cationization agent on the sensitivity of Bi cluster secondary ion mass spectrometry.

RATIONALE: Bi cluster secondary ion mass spectrometry (SIMS) is one of the most promising tools for precise analysis of synthetic polymers. However, the sensitivity in the high-mass region is still insufficient compared with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Accordingly, the effects of metal assistance (cationization agents) were investigated in this study. METHODS: To investigate the effects caused by varying the ionization agent, three different polyethylene glycol (PEG) samples were prepared, one with an Ag-deposited film, and two others mixed with Ag and Na, respectively. The measurements were performed by using a commercial Bi cluster SIMS and MALDI-TOFMS systems. The mass spectrum obtained with MALDI-TOFMS was used as a reference molecular weight distribution to evaluate the effects of molecular weight and primary ion species (Bi+ , Bi3+ , Bi32+ ) on the sensitivity of Bi cluster SIMS. RESULTS: The intensity of each secondary ion was the highest in Bi32+ irradiation, and the lowest in Bi+ irradiation. Regarding the cationization agents, the secondary ion yield was the highest for the sample mixed with Ag, while the degree of decay of sensitivity along with the increase in molecular weight was the smallest for the sample mixed with Na. CONCLUSIONS: It was suggested that the cationization mechanism consists of pre-formed ionization and gas-phase ionization processes. The sensitivity of Bi cluster SIMS decreases to approximately one-fiftieth in every 1000 u. These results might help in understanding the mechanism of cationization and further enhancement of secondary ion yields of polymers. Copyright © 2016 John Wiley & Sons, Ltd.

Yields and images of secondary ions from organic materials by different primary Bi ions in time-of-flight secondary ion mass spectrometry.

RATIONALE: Bi cluster ions are used as a source of primary ions for time-of-flight secondary ion mass spectrometry (TOF-SIMS), and it has been recognized that secondary ion yields of macromolecules are higher with Bi cluster ions than with monomer ions or other cluster ions such as Cs(+), Ga(+) and Aun (+). However, the analysis conditions of Bi cluster TOF-SIMS are not sufficiently established. This study provides information on the secondary ion yields, damage cross-section and spatial resolution obtained with different primary Bi ions. METHODS: We investigated the secondary ion yields, damage cross-section and spatial resolution using three different primary Bi ions in TOF-SIMS. The primary ions selected were Bi1(+), Bi3(+) and Bi3(2)(+) that were accelerated with 25 kV and the positively charged secondary ions were analyzed. The samples were 1, 2-distearoyl-sn-glycero-3-phosphocholine (C44H88NO8P, DSPC), which is a typical lipid, and N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (C44H32N2, NPD) and 4,4',4"-tris[2-naphthyl(phenyl)amino]triphenylamine (C66H48N4, 2-TNATA), which are organic functional materials. RESULTS: Although the secondary ion yields of DSPC were highest when measured with Bi3(+), the spatial resolution obtained from all DSPC analyses could not be evaluated because of the low intensity of the secondary molecular ions. On the other hand, for both NPD and 2-TNATA, the secondary ion yields were highest when imaged with Bi3(2)(+). Also, we obtained the highest spatial resolution using Bi3(2)(+). In the analysis of all molecules, the damage cross-section obtained with Bi3(2)(+) was also the highest. CONCLUSIONS: When secondary ions were sensitively detected, images of the high spatial resolution were obtained by using Bi3(2)(+). On the other hand, when the secondary ion sensitivity was low, the spatial resolution depended on the yields of secondary ions, implying that the selection of the primary ion species is crucial for SIMS analysis of large molecules.

Age-Adjusted Glycated Albumin at Diagnosis is more Correlated with the Product of Age and Plasma Glucose than Plasma Glucose Alone in Patients with Neonatal Diabetes Mellitus.

BACKGROUND: We previously showed that glycated albumin (GA) is a useful glycemic control indicator in patients with neonatal diabetes mellitus (NDM), and that age-adjusted GA (Aa-GA) can reflect more accurately glycemic control status. Here, we investigated whether the age at diagnosis influences Aa-GA at diagnosis of NDM. METHODS: Eight patients with NDM whose GA was measured at diagnosis (age at diagnosis: 39 ± 18 days; GA: 31.3 ± 7.6%; Aa-GA: 47.1 ± 10.3%; plasma glucose: 525 ± 194 mg/dl) were included. Aa-GA was calculated as follows: Aa-GA = GA × 14.0/[1.77 × log-age (days) + 6.65]. Correlations of GA or Aa-GA at diagnosis with its logarithmically transformed age in days (log-age), plasma glucose, and their product were investigated. RESULTS: GA at diagnosis was not significantly correlated with log-age or plasma glucose. On the other hand, Aa-GA at diagnosis was significantly positively correlated with plasma glucose (R = 0.75, P = 0.031) and was more strongly positively correlated with the product of plasma glucose and log-age (R = 0.82, P = 0.012) although it was not correlated with log-age. CONCLUSION: Aa-GA at diagnosis is influenced by both age in days and plasma glucose. This finding is likely to show the aspect that age in days is almost equal to diabetes duration because glycemic control indicators including GA reflect the weighted mean of plasma glucose.

A case of pancreatic agenesis and congenital heart defects with a novel GATA6 nonsense mutation: evidence of haploinsufficiency due to nonsense-mediated mRNA decay.

Recently, GATA6 heterozygous loss-of-function mutations were reported to cause pancreatic agenesis and congenital heart defects (PACHD [OMIM:600001]). However, the molecular mechanisms resulting from premature termination codons have not been examined in this disorder. The objective of this study was to perform a genetic analysis of a patient with PACHD. A female patient presented with ventricular septal defect, patent ductus arteriosus, and congenital diaphragmatic hernia at birth. Permanent neonatal diabetes mellitus and pancreatic exocrine deficiency due to pancreatic agenesis was diagnosed at 1 month of age. PCR-direct sequencing of GATA6 revealed that the patient is heterozygous for a novel de novo nonsense mutation of c.1477C>T, p. Arg493X in exon 5. RT-PCR direct sequencing of the RT-PCR products of total RNA from peripheral blood of the patient for the region encompassing exons 4-6 revealed only the wild-type allele. This finding provides the evidence for the occurrence of nonsense-mediated mRNA decay (NMD) in the p.Arg493X mutation. Quantitative RT-PCR analysis revealed that the expression of GATA6 transcript in the patient was less than half compared with normal control samples. This is the first evidence that GATA6 haploinsufficiency is caused by NMD in vivo, and we conclude that GATA6 haploinsufficiency causes not only PACHD but may affect other organs derived from the endoderm. Further screenings of GATA6 mutations in patients with various forms of diabetes and/or congenital heart disease with other visceral malformation may reveal the impact of GATA6 mutations on diabetes and congenital malformation.

Diameter measurement of vascular model on CT angiography using model-based iterative reconstruction: effect of tube current on accuracy.

OBJECTIVE: The purpose of this study was to evaluate the effect of tube current on the accuracy of vascular diameter measurements on CT angiography using model-based iterative reconstruction (MBIR). MATERIALS AND METHODS: We constructed a physical phantom composed of nine vascular models of three wall thicknesses filled with contrast material of three densities and scanned the phantom using a 64-MDCT unit with tube currents of 80, 40, 20, and 10 mA. We reconstructed raw data using MBIR and filtered back projection (FBP) algorithms and examined image sharpness by edge rise distance using four tube currents in each of the two reconstruction methods. We measured the mean inner diameter for each model for each set of image data using MBIR with the four tube currents (80, 40, 20, and 10 mA) and FBP with tube current of 80 mA. RESULTS: Sharpness decreased as tube current decreased using MBIR (p < 0.0001) but did not differ significantly among the four tube currents using FBP (p = 0.0506). Sharpness using MBIR with 10 mA tube current was comparable to or significantly worse than that with FBP. The measurement error using MBIR tended to increase as tube current decreased. The measurement errors using MBIR with 10 mA tube current were comparable to or significantly larger than those using FBP for eight of the nine vascular models. CONCLUSION: By decreasing spatial resolution, MBIR with lower tube current can enhance errors in measurement of vascular diameter and should be applied carefully in evaluating vessel diameter.