Early detection of hypervascularization in hepatocellular carcinoma (≤2 cm) on hepatic arterial phase with virtual monochromatic imaging: Comparison with low-tube voltage CT.

This study aims to assess the diagnostic value of virtual monochromatic image (VMI) at low keV energy for early detection of small hepatocellular carcinoma (HCC) in hepatic arterial phase compared with low-tube voltage (80 kVp) CT generated from dual-energy CT (DE-CT). A total of 107 patients with 114 hypervascular HCCs (≤2 cm) underwent DE-CT, 140 kVp, blended 120 kVp, and 80 kVp images were generated, as well as 40 and 50 keV. CT numbers of HCCs and the standard deviation as image noise on psoas muscle were measured. The contrast-to-noise ratios (CNR) of HCC were compared among all techniques. Overall image quality and sensitivity for detecting HCC hypervascularity were qualitatively assessed by three readers. The mean CT numbers, CNR, and image noise were highest at 40 keV followed by 50 keV, 80 kVp, blended 120 kVp, and 140 kVp. Significant differences were found in all evaluating endpoints except for mean image noise of 50 keV and 80 kVp. Image quality of 40 keV was the lowest, but still it was considered acceptable for diagnostic purposes. The mean sensitivity for detecting lesion hypervascularity with 40 keV (92%) and 50 keV (84%) was higher than those with 80 kVp (56%). Low keV energy images were superior to 80 kVp in detecting hypervascularization of early HCC.

Effect of decreased contrast injection flow rate on aortic enhancement in 80-KV peak CT with contrast dose reduction.

BACKGROUND: Effect of decreased injection flow rate of contrast agent at the same iodine dose and delivery rate on aortic enhancement has not been clearly elucidated. PURPOSE: To evaluate the effect of decreased injection flow rate of contrast agent on aortic peak enhancement in a dynamic flow phantom and on aortic enhancement in clinical dynamic 80-kVp computed tomography (CT) with contrast dose reduction. MATERIAL AND METHODS: In the dynamic flow phantom experiment, the effect of a decreased injection flow rate at the same total iodine dose and delivery rate on simulated aortic peak enhancement was evaluated. In the clinical retrospective study, we searched 312 patients with renal dysfunction who underwent an 80-kVp abdominal dynamic CT with 40% reduction of contrast agent from a standard 120-kVp protocol and measured the aortic enhancement at the level of the hepatic hilum. Independent predictors for aortic enhancement were determined by multiple linear regression analysis, and after adjustment of significant predictors, independent variables for acquiring optimal aortic enhancement, ≥300 HU, were determined by multiple logistic regression analysis. RESULTS: In the phantom experiment, decreased flow rate showed a significant but small descent effect (6%-9%) on simulated aortic peak enhancement. In the multiple linear regression analysis, only age was an independent predictor of aortic enhancement; there was no independent predictor for optimal age-adjusted aortic enhancement of ≥300 HU. CONCLUSIONS: Decreased injection flow rate had a small influence on aortic enhancement in vitro but had no significant effect on the aortic enhancement in clinical dynamic 80-kVp CT.

Effect of Diameter and Number of Hepatocellular Carcinomas on Survival After Resection, Transarterial Chemoembolization, and Ablation.

INTRODUCTION: Most studies predicting survival after resection, transarterial chemoembolization (TACE), and ablation analyzed diameter and number of hepatocellular carcinomas (HCCs) as dichotomous variables, resulting in an underestimation of risk variation. We aimed to develop and validate a new prognostic model for patients with HCC using largest diameter and number of HCCs as continuous variables. METHODS: The prognostic model was developed using data from patients undergoing resection, TACE, and ablation in 645 Japanese institutions. The model results were shown after balanced using the inverse probability of treatment-weighted analysis and were externally validated in an international multi-institution cohort. RESULTS: Of 77,268 patients, 43,904 patients, including 15,313 (34.9%) undergoing liver resection, 13,375 (30.5%) undergoing TACE, and 15,216 (34.7%) undergoing ablation, met the inclusion criteria. Our model (http://www.u-tokyo-hbp-transplant-surgery.jp/about/calculation.html) showed that the 5-year overall survival (OS) in patients with HCC undergoing these procedures decreased with progressive incremental increases in diameter and number of HCCs. For patients undergoing resection, the inverse probability of treatment-weighted-adjusted 5-year OS probabilities were 10%-20% higher compared with patients undergoing TACE for 1-6 HCC lesions <10 cm and were also 10%-20% higher compared with patients undergoing ablation when the HCC diameter was 2-3 cm. For patients undergoing resection and TACE, the model performed well in the external cohort. DISCUSSION: Our novel prognostic model performed well in predicting OS after resection and TACE for HCC and demonstrated that resection may have a survival benefit over TACE and ablation based on the diameter and number of HCCs.

Quantitative analysis of gadoxetic acid-enhanced MRI for the differential diagnosis of focal liver lesions: Comparison between estimated intralesional gadoxetic acid retention by T1 mapping and conventional processing methods.

PURPOSE: To compare the estimated quantity of intratumor gadoxetic acid retention using T1 mapping of gadoxetic acid-enhanced magnetic resonance imaging (MRI) versus conventional processing methods for the differential diagnosis of focal liver lesions. METHODS: Seventy patients with hepatic lesions (colorectal metastasis (CRM) [n = 28], hepatocellular carcinoma (HCC) [n = 20], hemangioma [n = 12], and intrahepatic cholangiocarcinoma (ICC) [n = 10]) underwent gadoxetic acid-enhanced MRI, including pre- and post-contrast T1-weighted imaging and T1 mapping. Quantitative analyses included the lesion-to-liver signal intensity ratio (SIR) on hepatobiliary phase images, the pre- and post-contrast lesion T1 value difference (ΔT1 [ms]), and the lesion retention index (LRI [%]), which was the estimated intralesional gadoxetic acid retention calculated on pre- and post-contrast T1 maps using a two-compartment pharmacokinetic model. Results were compared between the four subcategories of focal liver lesions using the Kruskal-Wallis test, followed by the post-hoc Dunn's test and receiver operating characteristic (ROC) analysis to distinguish between pairs of the four lesion subcategories. RESULTS: This study identified significant differences in the LRI of the four lesion subcategories (p <  0.01), without significant differences in ΔT1 or SIR. Post-hoc analysis demonstrated significant differences in CRM vs. hemangioma (p <  0.01), hemangioma vs. ICC (p <  0.01), and HCC vs. ICC (p =  0.047) for the LRI. CONCLUSIONS: The quantity of intratumor gadoxetic acid retention estimated using pre- and post- contrast T1 mapping could distinguish focal liver lesions, unlike conventional processing methods, and captured unique lesion characteristics.

Uptake of gadoxetic acid in hepatobiliary phase magnetic resonance imaging and transporter expression in hypovascular hepatocellular nodules.

AIMS: To evaluate the association between contrast patterns on gadoxetic acid-enhanced hepatobiliary phase (HBP) MR images and transporter expression in surgically resected hypovascular hepatocellular nodules including early hepatocellular carcinomas (HCCs). METHODS: Forty-two hypovascular hepatic nodules and 43 hypervascular HCCs as a control were included in this retrospective study. Contrast of the nodules on HBP images was graded as hypo-, iso-, or hyperintense. Histopathological assessment was performed in the context of multistep hepatocarcinogenesis. Immunohistochemical staining of organic anion transporter 1B3 (OATP1B3) and multidrug resistance protein 2 (MRP2) was performed. Cramer's coefficient was used to determine the linear relationship between contrast grades and transporter expression, and the Cochran-Armitage trend test was used to determine the relationship between transporter expression and progression of multistep hepatocarcinogenesis. RESULTS: Moderate linear relationships between contrast grades and OATP1B3 expression were observed for both hypo- and hypervascular nodules. OATP1B3 expression was negatively correlated with the progression of multistep hepatocarcinogenesis. MRP2 expression was not associated with the contrast grades or histopathological results. CONCLUSION: OATP1B3 expression was associated with contrast grades of hepatocellular nodules observed in HBP image of gadoxetic acid-enhanced MRI in the hypovascular hepatocellular nodules and was negatively correlated with hepatocarcinogenesis.

Optimal Combination of Features on Gadoxetate Disodium-enhanced MR Imaging for Non-invasive Differential Diagnosis of Hepatocellular Carcinoma: The JAMP-HCC Study.

PURPOSE: To determine the optimal combination of gadoxetate disodium-enhanced magnetic resonance imaging (MRI) findings for the diagnosis of hepatocellular carcinoma (HCC) and to compare its diagnostic ability to that of dynamic computed tomography (CT) in patients with chronic liver disease. METHODS: This multi-institutional study consisted of two parts: Study 1, a retrospective study to determine the optimal combination of gadoxetate disodium-enhanced MRI findings (decision tree and logistic model) to distinguish HCC (n = 199) from benign (n = 81) or other malignant lesions (n = 95) (375 nodules in 269 patients) and Study 2, a prospective study to compare the diagnostic ability of gadoxetate disodium-enhanced MRI to distinguish HCC (n = 73) from benign (n = 15) or other malignant lesions (n = 12) with that of dynamic CT (100 nodules in 83 patients). Two radiologists independently evaluated the imaging findings (Study 1 and 2) and made a practical diagnosis (Study 2). RESULTS: In Study 1, rim or whole enhancement on arterial phase images, signal intensities on T2-weighted/diffusion-weighted/portal venous/transitional/hepatobiliary phase images, and signal drop on opposed-phase images were independently useful for differential diagnosis. In Study 2, the accuracy, sensitivity, negative predictive value, and negative likelihood ratio of the CT decision tree (reader 2) were higher than those of MRI Model 2 (P = 0.015-0.033). There were no other significant differences in diagnostic ability (P = 0.059-1.000) and radiologist-made practical diagnosis (P = 0.059-1.000) between gadoxetate disodium-enhanced MRI and CT. CONCLUSION: We identified the optimal combination of gadoxetate disodium-enhanced MRI findings for HCC diagnosis. However, its diagnostic ability was not superior to that of dynamic CT.

Analysis of electropharmacological effects of AVE0118 on the atria of chronic atrioventricular block dogs: characterization of anti-atrial fibrillatory action by atrial repolarization-delaying agent.

AVE0118, an inhibitor of IKur, Ito and IK,ACh, was in the drug pipeline for atrial fibrillation. To investigate the limitation of AVE0118 as an anti-atrial fibrillatory drug, we studied its electropharmacological effects particularly focusing on the anti-atrial fibrillatory action as reverse translational research. We adopted the chronic atrioventricular block beagle dogs (n = 4), having a pathophysiology of bradycardia-associated, volume overload-induced chronic heart failure, in which the atrial fibrillation was induced by 10 s of burst pacing on atrial septum. AVE0118 in doses of 0.24 and 1.2 mg/kg, i.v. over 10 min hardly altered electrophysiological variables. Meanwhile, AVE0118 in a dose of 6 mg/kg, i.v. over 10 min delayed the inter-atrial conduction in a frequency-dependent manner and prolonged the atrial effective refractory period in a reverse frequency-dependent manner, whereas it did not significantly alter the duration of atrial fibrillation or its cycle length. The increment of atrial effective refractory period was 3.3 times greater compared with that of ventricular one at a basic cycle length of 400 ms. Torsade de pointes was not induced during the experimental period. Thus, AVE0118 may possess a favorable cardiac safety pharmacological profile, but its weak anti-atrial fibrillatory effect would indicate the limitation of atrial repolarization-delaying agents for suppressing atrial fibrillation.

Effect of Ultra High-Resolution Computed Tomography and Model-Based Iterative Reconstruction on Detectability of Simulated Submillimeter Artery.

OBJECTIVE: To evaluate the effect of ultra high-resolution computed tomography (UHRCT) and model-based iterative reconstruction (MBIR) on the detectability of simulated submillimeter artery. METHODS: A small vessel phantom ranging from 0.4 to 2.0 mm in diameter and edge phantoms of low to high attenuation values were scanned by UHRCT (super-high-resolution mode and normal-resolution-mode) and conventional CT, and data were reconstructed by MBIR and filtered back projection (FBP). Vessel detectability was assessed subjectively and the effective size at which 50% of response was achieved (ES50 [mm]) was calculated. Modulation transfer function (MTF) was calculated by an edge spread function method. RESULTS: ES50 of super high-resolution mode (0.36 mm for MBIR and 0.50 mm for FBP) was significantly smaller than those of normal-resolution mode (P < 0.01). In the MTF analysis, the MTF of MBIR improved as the edge phantom attenuation increased, whereas that of FBP was stable. CONCLUSIONS: Both UHRCT and MBIR are effective for the detectability of simulated submillimeter artery.

The inferior mesenteric artery arising from the superior mesenteric artery demonstrated with 3D-CT: A case report.

The inferior mesenteric artery arising from the superior mesenteric artery is an extremely rare anatomic variation. We report a case with this variation demonstrated with 3-dimensional contrast-enhanced computed tomography, which later was confirmed at surgery. The ordinary inferior mesenteric artery arising from the aorta was absent. Previously reported cases with this variation are reviewed. 3-dimensional contrast-enhanced computed tomography is useful for in vivo visualization of aberrant arterial anatomy.

Seeding of a Tumor in the Gastric Wall after Endoscopic Ultrasound-guided Fine-needle Aspiration of Solid Pseudopapillary Neoplasm of the Pancreas.

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is widely used as a first-line procedure for the definitive diagnosis of pancreatic solid tumor. Adverse events associated with the EUS-FNA procedure include acute pancreatitis, bleeding, infection, and duodenal perforation. Rarely, pancreatic tumors disseminate in the peritoneal cavity or seed in the gastric wall via the biopsy needle tract after EUS-FNA. Such seeding has been noted primarily in cases of adenocarcinomas and has not been associated with solid pseudopapillary neoplasm (SPN), a rare and potentially malignant tumor of the pancreas. This is the first report of a case of tumor seeding in the gastric wall after EUS-FNA of pancreatic SPN.

An Unusual Ovarian Mucinous Borderline Tumor with a Large Solid Component.

Herein, we report magnetic resonance imaging (MRI) findings of a mucinous borderline tumor of the ovary, which we observed as a mainly solid tumor with large solid components in the lower pelvic cavity. The appearance of ovarian epithelial tumors on imaging is often complex. Cystic to solid appearing masses may be observed, and they often resemble epithelial carcinoma. Due to mucinous or hemorrhage components of packed small or microcystic components, MRI depicts slightly high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. Mucinous borderline tumor of the ovary with a large solid component is very rare, but it is clinically important to recognize the possibility of mucinous borderline tumor to avoid unnecessary surgical intervention.

Magnetic resonance elastography is as accurate as liver biopsy for liver fibrosis staging.

BACKGROUND: Liver MR elastography (MRE) is available for the noninvasive assessment of liver fibrosis; however, no previous studies have compared the diagnostic ability of MRE with that of liver biopsy. PURPOSE: To compare the diagnostic accuracy of liver fibrosis staging between MRE-based methods and liver biopsy using the resected liver specimens as the reference standard. STUDY TYPE: A retrospective study at a single institution. POPULATION: In all, 200 patients who underwent preoperative MRE and subsequent surgical liver resection were included in this study. Data from 80 patients were used to estimate cutoff and distributions of liver stiffness values measured by MRE for each liver fibrosis stage (F0-F4, METAVIR system). In the remaining 120 patients, liver biopsy specimens were obtained from the resected liver tissues using a standard biopsy needle. FIELD STRENGTH/SEQUENCE: 2D liver MRE with gradient-echo based sequence on a 1.5 or 3T scanner was used. ASSESSMENT: Two radiologists independently measured the liver stiffness value on MRE and two types of MRE-based methods (threshold and Bayesian prediction method) were applied. Two pathologists evaluated all biopsy samples independently to stage liver fibrosis. Surgically resected whole tissue specimens were used as the reference standard. STATISTICAL TESTS: The accuracy for liver fibrosis staging was compared between liver biopsy and MRE-based methods with a modified McNemar's test. RESULTS: Accurate fibrosis staging was achieved in 53.3% (64/120) and 59.1% (71/120) of patients using MRE with threshold and Bayesian methods, respectively, and in 51.6% (62/120) with liver biopsy. Accuracies of MRE-based methods for diagnoses of ≥F2 (90-91% [108-9/120]), ≥F3 (79-81% [95-97/120]), and F4 (82-85% [98-102/120]) were statistically equivalent to those of liver biopsy (≥F2, 79% [95/120], P ≤ 0.01; ≥F3, 88% [105/120], P ≤ 0.006; and F4, 82% [99/120], P ≤ 0.017). DATA CONCLUSION: MRE can be an alternative to liver biopsy for fibrosis staging. LEVEL OF EVIDENCE: 3. Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1268-1275.

Gadoxetic acid disodium-enhanced MR imaging of cholangiolocellular carcinoma of the liver: imaging characteristics and histopathological correlations.

OBJECTIVES: To review the gadoxetic acid disodium (EOB)-enhanced magnetic resonance (MR) imaging features of cholangiolocellular carcinoma (CoCC) of the liver and compare them with those of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). METHODS: EOB-enhanced MR images of 19 patients with CoCC, 23 with ICC, and 51 with HCC were retrospectively evaluated qualitatively and quantitatively. Univariate and multivariate analyses were performed to determine the characteristic MR features of CoCC with histopathological-imaging correlation. RESULTS: Multivariate logistic regression analysis showed that dot-/band-shaped internal enhancement during the arterial and portal phases (P < 0.001), and larger arterial ring enhancement ratio (CoCC, 0.13 ± 0.04; ICC, 0.074 ± 0.04; P = 0.013) were significantly independently associated with CoCC in contrast to ICC, whereas several MR features including progressive enhancement during the portal and late phases (P < 0.001), target appearance in the hepatocyte phase (P = 0.004), and vessel penetration (P = 0.013) were significantly more frequently associated with CoCC than HCC. The dot-/band-like internal enhancement (78.9% of CoCCs) histopathologically corresponded to the tumour cell nest with vascular proliferations and retained Glisson's sheath structure. CONCLUSIONS: EOB-enhanced MR features of CoCC largely differ from those of HCC but are similar to those of ICC. However, the finding of thicker arterial ring enhancement with dot-/band-like internal enhancement could help differentiate CoCC from ICC. KEY POINTS: • Gadoxetic acid-enhanced MR features of cholangiolocellular carcinoma (CoCC) resembled those of intrahepatic cholangiocarcinoma (ICC). • Gadoxetic acid-enhanced MR features of CoCC largely differed from those of hepatocellular carcinoma. • Dot-/band-like internal enhancement of CoCC may be helpful for differentiating from ICC. • Arterial ring enhancement of CoCC was larger than that of ICC.

Outcome of hypovascular hepatic nodules with positive uptake of gadoxetic acid in patients with cirrhosis.

OBJECTIVES: To evaluate the longitudinal risk to patients with cirrhosis of hypervascular hepatocellular carcinoma (HCC) developing from hypovascular hepatic nodules that show positive uptake of gadoxetic acid (hyperintensity) on hepatocyte phase images. METHODS: In 69 patients, we evaluated findings from serial follow-up examinations of 633 hepatic nodules that appeared hypovascular and hyperintense on initial gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) until the nodules demonstrated hypervascularity and were diagnosed as hypervascular HCC. Cox analyses were performed to identify risk factors for the development of hypervascular HCCs from the nodules. RESULTS: The median follow-up was 663 days (range, 110 to 1215 days). Hypervascular HCCs developed in six of the 633 nodules (0.9 %) in five of the 69 patients. The only independent risk factor, the nodule's initial maximum diameter of 10 mm or larger, demonstrated a hazard ratio of 1.25. The one-year risk of hypervascular HCC developing from a nodule was 0.44 %. The risk was significantly higher for nodules of larger diameter (1.31 %) than those smaller than 10 mm (0.10 %, p < 0.01). CONCLUSIONS: Hypervascular HCC rarely develops from hypovascular, hyperintense hepatic nodules. We observed low risk even for nodules of 10 mm and larger diameter at initial examination. KEY POINTS: • Hypervascularization was rare on follow-up examination of hypovascular, hyperintense nodules • The risk of hypervascularization in a nodule increased with large size • Hypovascular, hyperintense nodules require neither treatment nor more intense follow-up.

Comparison of diagnostic accuracies of two- and three-dimensional MR elastography of the liver.

PURPOSE: To evaluate the effect of imaging sequence (spin-echo echo-planar imaging [EPI] and gradient-echo [GRE]) and postprocessing method (two-dimensional [2D] and 3D inversion algorithms) on liver MR elastography (MRE) and to validate the diagnostic performance of EPI-MRE3D versus conventional GRE-MRE2D for liver fibrosis staging. MATERIALS AND METHODS: Three MRE methods (EPI-MRE3D , EPI-MRE2D , and GRE-MRE2D ) were performed on soft and mildly stiff phantoms and 58 patients with chronic liver disease using a 3 Tesla clinical MRI scanner, and stiffness values were compared among the three methods. A validation study comprised 73 patients with histological liver fibrosis (F0-4, METAVIR system). Areas under the receiver operating characteristic curves (AUCs) and accuracies for diagnosing significant fibrosis (F3-4) and cirrhosis (F4) were compared between EPI-MRE3D and GRE-MRE2D . RESULTS: Stiffness values of the soft and mildly stiff phantoms were 2.4 kPa and 4.0 kPa by EPI-MRE3D ; 2.6 kPa and 4.2 kPa by EPI-MRE2D ; and 2.7 kPa and 4.2 kPa by GRE-MRE2D . In patients, EPI-MRE3D provided significantly lower stiffness values than other methods (P < 0.001). However, there was no significant difference between GRE-MRE2D and EPI-MRE2D (P = 0.12). The AUCs and accuracies of EPI-MRE3D and GRE-MRE2D were statistically equivalent in the diagnoses of significant fibrosis (F3-4) and cirrhosis (F4) (all P < 0.005). CONCLUSION: EPI-MRE3D showed modestly lower liver stiffness values than conventional GRE-MRE2D . The diagnostic performances of EPI-MRE3D and GRE-MRE2D were equivalent for liver fibrosis staging. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1163-1170.

Acute Adverse Reactions to Nonionic Iodinated Contrast Media for CT: Prospective Randomized Evaluation of the Effects of Dehydration, Oral Rehydration, and Patient Risk Factors.

OBJECTIVE: The objective of our study was to determine the effects of dehydration and oral rehydration on the incidence of acute adverse reactions to iodinated contrast media administered during abdominal and pelvic CT in outpatients. SUBJECTS AND METHODS: For our prospective randomized study performed at a single institution, adult outpatients undergoing contrast-enhanced abdominal CT were randomly divided into a rehydration group (n = 2244 patients [1379 men and 865 women]; mean age, 65.2 years; age range, 18-90 years) and a control group (n = 3715 [2112 male patients and 1603 female patients]; mean age, 65.8 years; age range, 17-96 years), which included an age- and sex-matched subgroup (adjusted control group, n = 2244). The rehydration group received an oral rehydration solution (500 mL of liquid in which osmotic pressure is adjusted to enhance gastrointestinal absorption) before abdominal and pelvic CT. Patients were also divided into subclinically dehydrated (n = 997) and hydrated (n = 4962) groups according to their answers to a questionnaire that they completed before the CT examination. The patients were interviewed about contrast-induced adverse reactions before they left the CT room, and the reactions were categorized as allergiclike or physiologic. The incidence of reactions was compared between the rehydration and control groups and between the subclinical dehydration and hydrated groups. The rehydration and control groups were compared with an unpaired t test or a chi-square or Fisher test. RESULTS: The overall incidence of an acute adverse reaction was 4.3% (254/5959); the acute adverse reactions included 136 allergiclike and 118 physiologic reactions. Fourteen allergiclike and nine physiologic reactions were moderate grade, and none was severe. There was no significant difference between the rehydration group and adjusted control group in the overall incidence of adverse reactions (99/2244 [4.4%] vs 100/2244 [4.5%], respectively; p = 0.9422) or between the subclinically dehydrated group and hydrated group in the incidence of allergiclike reactions (25/997 [2.5%] vs 111/4962 [2.2%], p = 0.6062) and physiologic reactions (22/997 [2.2%] vs 96/4962 [1.9%], p = 0.5793). Younger age was a risk factor for both allergiclike and physiologic reactions (p ≤ 0.0019). CONCLUSION: Dehydration and oral rehydration did not affect the incidence of acute adverse reactions to iodinated contrast material for abdominal and pelvic CT in our randomized prospective trial.

Relationship between diverse patient body size- and image acquisition-related factors, and quantitative and qualitative image quality in coronary computed tomography angiography: a multicenter observational study.

PURPOSE: We investigated the effects of patient- and image acquisition-related factors on the image quality in coronary CT angiography (CCTA). MATERIALS AND METHODS: We enrolled 1197 patients (728 men; 65 ± 12 years). All underwent CCTA under the routine scan protocol in 23 participating hospitals. The subjective image quality (3-point Likert scale: excellent, good, and poor) and the attenuation of the left and right coronary artery (LCA, RCA) were recorded; the effects of patient and image acquisition-related factors on vascular attenuation were then compared. RESULTS: The mean LCA attenuation was 515.2 ± 65.8 (excellent), 401.4 ± 63.4 (good), and 319.5 ± 47.6 HU (poor). The corresponding RCA attenuation was 496.6 ± 67.6, 390.5 ± 58.5, and 308.5 ± 50.7 HU, respectively. Univariate analysis revealed significant associations between sufficient coronary attenuation (> 400 HU) and the age, gender, body surface area (BSA), number of detectors, contrast synchronization, scan mode, and the fractional contrast dose. Multivariate analysis revealed that the bolus tracking method, prospective electrocardiogram gating, and fractional contrast dose were significantly associated with sufficient coronary enhancement. CONCLUSION: BSA and fractional contrast dose are the most important patient- and image acquisition-related factors for sufficient coronary attenuation in CCTA.

Biochemical and Clinical Predictive Approach and Time Point Analysis of Hepatobiliary Phase Liver Enhancement on Gd-EOB-DTPA-enhanced MR Images: A Multicenter Study.

Purpose To identify biochemical factors associated with liver enhancement over time on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images and predict the optimal time point of the hepatobiliary phase in various clinical settings. Materials and Methods This study was approved by the institutional review boards, and written informed consent was obtained from the 1903 patients enrolled. Simple and multiple logistic regression analyses were performed to investigate the biochemical factors associated with liver-to-spleen contrast (LSC) of at least 1.5 in the hepatobiliary phase. Changes in LSC and lesion-to-liver contrast (LLC) of lesions over time (at 5, 10, 15, and 20 minutes) were investigated with a linear mixed-effects model in patients and lesions. For LSC, the optimal cutoff value was determined with receiver operating characteristic analysis of the most significant variable. Differences in LSC and LLC were analyzed in various clinical settings. Results Ultimately, 1870 patients were evaluated, as 33 were excluded according to study criteria. Prothrombin (PT) activity, total bilirubin level (P = .020), and total cholesterol level (P = .005) were significantly associated with LSC of at least 1.5 at 20 minutes, and PT activity was identified as the most significant factor (odds ratio, 1.271; 95% confidence interval: 1.109, 1.455; P = .001). LSC of at least 1.5 at 20 minutes with PT activity of at least 86.9% and less than 86.9% occurred in 555 of 626 patients (88.6%) and 388 of 575 patients (67.5%), respectively. Satisfactory liver enhancement at 20 minutes was significantly more likely to be achieved by patients with hepatitis B virus than by those with hepatitis C virus (P < .001) and by patients with metastasis than by those with hepatocellular carcinoma (P < .001). No significant difference in LLC was observed in patients examined at 1.5 and 3.0 T (P = .133). Conclusion Hepatic enhancement is significantly associated with PT activity, total bilirubin level, and total cholesterol level. PT activity of at least 86.9% could be used to shorten examination times at Gd-EOB-DTPA-enhanced MR imaging. © RSNA, 2016 Online supplemental material is available for this article.