Multiphasic Computed Tomography Research Articles

Diagnostic performance of CT, MRI and PET/CT in patients with suspected colorectal liver metastases: the superiority of MRI.

Meticulous imaging of colorectal liver metastases (CRLM) is mandatory to optimize outcome after liver resection. However, the detection of CRLM is still challenging. To evaluate prospectively if magnetic resonance imaging (MRI) with diffusion-weighted and Gd-EOB-DTPA-enhanced sequences had a better diagnostic performance for CRLM compared to computed tomography (CT) and fluorine-18 fluorodeoxyglucose positron emission tomography (PET/CT). Forty-six patients scheduled for resection of suspected CRLM were evaluated prospectively from September 2011 to January 2013. None of the patients had undergone previous treatment for their CRLM. Multiphase CT, liver MRI with diffusion-weighted and dynamic Gd-EOB-DTPA-enhanced sequences and low-dose PET/CT were performed. Two independent, blinded readers evaluated the examinations. The reference standard was histopathological confirmation (81/140 CRLM) or follow-up. A total of 140 CRLM and 196 benign lesions were identified. On a per-lesion basis, MRI had the significantly highest sensitivity overall and for CRLM < 10 mm (P < 0.001). Overall sensitivity/specificity and PPV/NPV were 68%/94% and 89%/81% for CT, 90%/87% and 82%/93% for MRI, and 61%/99% and 97%/78% for PET/CT. For CRLM < 10 mm it was 16%/96% and 54%/80% for CT, 74%/88% and 64%/93% for MRI, and 9%/98% and 57%/79% for PET/CT. MRI had the significantly highest sensitivity compared with CT and PET/CT, particularly for CRLM < 10 mm. Therefore, detection of CRLM should be based on MRI.

Predictors of CT Radiation Dose and Their Effect on Patient Care: A Comprehensive Analysis Using Automated Data.

Purpose To determine patient, vendor, and institutional factors that influence computed tomography (CT) radiation dose. Materials and Methods The relevant institutional review boards approved this HIPAA-compliant study, with waiver of informed consent. Volume CT dose index (CTDIvol) and effective dose in 274 124 head, chest, and abdominal CT examinations performed in adult patients at 12 facilities in 2013 were collected prospectively. Patient, vendor, and institutional characteristics that could be used to predict (a) median dose by using linear regression after log transformation of doses and (b) high-dose examinations (top 25% of dose within anatomic strata) by using modified Poisson regression were assessed. Results There was wide variation in dose within and across medical centers. For chest CTDIvol, overall median dose across all institutions was 11 mGy, and institutional median dose was 7-16 mGy. Models including patient, vendor, and institutional factors were good for prediction of median doses (R2 = 0.31-0.61). The specific institution where the examination was performed (reflecting the specific protocols used) accounted for a moderate to large proportion of dose variation. For chest CTDIvol, unadjusted median CTDIvol was 16.5 mGy at one institution and 6.7 mGy at another (adjusted relative median dose, 2.6 mGy [95% confidence interval: 2.5, 2.7]). Several variables were important predictors that a patient would undergo high-dose CT. These included patient size, the specific institution where CT was performed, and the use of multiphase scanning. For example, while 49% of patients (21 411 of 43 696) who underwent multiphase abdominal CT had a high-dose examination, 8% of patients (4977 of 62 212) who underwent single-phase CT had a high-dose examination (adjusted relative risk, 6.20 [95% CI: 6.17, 6.23]). If all patients had been examined with single-phase CT, 69% (18 208 of 26 388) of high-dose examinations would have been eliminated. Patient size, institutional-specific protocols, and multiphase scanning were the most important predictors of dose (change in R2 = 8%-32%), followed by manufacturer and iterative reconstruction (change in R2, 0.2%-15.0%). Conclusion CT doses vary considerably within and across facilities. The primary factors that influenced dose variation were multiphase scanning and institutional protocol choices. It is unknown if the variation in these factors influenced diagnostic accuracy. © RSNA, 2016.

Material Separation Using Dual-Energy CT: Current and Emerging Applications.

Dual-energy (DE) computed tomography (CT) offers the opportunity to generate material-specific images on the basis of the atomic number Z and the unique mass attenuation coefficient of a particular material at different x-ray energies. Material-specific images provide qualitative and quantitative information about tissue composition and contrast media distribution. The most significant contribution of DE CT-based material characterization comes from the capability to assess iodine distribution through the creation of an image that exclusively shows iodine. These iodine-specific images increase tissue contrast and amplify subtle differences in attenuation between normal and abnormal tissues, improving lesion detection and characterization in the abdomen. In addition, DE CT enables computational removal of iodine influence from a CT image, generating virtual noncontrast images. Several additional materials, including calcium, fat, and uric acid, can be separated, permitting imaging assessment of metabolic imbalances, elemental deficiencies, and abnormal deposition of materials within tissues. The ability to obtain material-specific images from a single, contrast-enhanced CT acquisition can complement the anatomic knowledge with functional information, and may be used to reduce the radiation dose by decreasing the number of phases in a multiphasic CT examination. DE CT also enables generation of energy-specific and virtual monochromatic images. Clinical applications of DE CT leverage both material-specific images and virtual monochromatic images to expand the current role of CT and overcome several limitations of single-energy CT. (©)RSNA, 2016.

Double-low protocol for hepatic dynamic CT scan: Effect of low tube voltage and low-dose iodine contrast agent on image quality.

The radiation-induced carcinogenesis from computed tomography (CT) and iodine contrast agent induced nephropathy has attracted international attention. The reduction of the radiation dose and iodine intake in CT scan is always a direction for researchers to strive. The purpose of this study was to evaluate the feasibility of a “double-low” (i.e., low tube voltage and low-dose iodine contrast agent) scanning protocol for dynamic hepatic CT with the adaptive statistical iterative reconstruction (ASIR) in patients with a body mass index (BMI) of 18.5 to 27.9 kg/m2.A total of 128 consecutive patients with a BMI between 18.5 and 27.9 kg/m2 were randomly assigned into 3 groups according to tube voltage, iodine contrast agent, and reconstruction algorithms. Group A (the “double-low” protocol): 100 kVp tube voltage with 40% ASIR, iodixanol at 270 mg I/mL, group B: 120 kVp tube voltage with filtered back projection (FBP), iodixanol at 270 mg I/ mL, and group C: 120 kVp tube voltage with FBP, ioversol at 350 mg I/ mL.The volume CT dose index (CTDIvol) and effective dose (ED) in group A were lower than those in group B and C (all P < 0.01). The iodine intake in group A was decreased by approximately 26.5% than group C, whereas no statistical difference was observed between group A and B (P > 0.05). There was no significant difference of the CT values between group A and C (P > 0.05), which both showed higher CT values than that in group B (P < 0.001). However, no statistic difference was observed in the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and image-quality scores among the 3 groups (all P > 0.05). Near-perfect consistency of the evaluation for group A, B, and C (Kenall's W = 0.921, 0.874, and 0.949, respectively) was obtained by the 4 readers with respect to the overall image quality.These results suggested that the “double-low” protocol with ASIR algorithm for multi-phase hepatic CT scan can dramatically decrease radiation dose and iodine intake with adequate image quality in patients with BMI of 18.5 to 27.9 kg/m2.

Liver Surface Nodularity Quantification from Routine CT Images as a Biomarker for Detection and Evaluation of Cirrhosis

Purpose To determine the accuracy, reproducibility, and intra- and interobserver agreement of a computer-based quantitative method to measure liver surface nodularity (LSN) from routine computed tomographic (CT) images as a biomarker for detection and evaluation of cirrhosis. Materials and Methods For this institutional review board-approved HIPAA-compliant retrospective study, adult patients with healthy livers (n = 24) or various stages of hepatitis C virus-induced chronic liver disease (n = 70) with routine nonenhanced and portal venous phase contrast agent-enhanced liver CT imaging with thick-section (5.0 mm) and thin-section (1.25-1.50 mm) axial images obtained between January 1, 2006, and March 31, 2011, were identified from the electronic medical records. A computer algorithm was developed to measure LSN and derive a score. LSN scores, splenic volume, and the ratio of left lateral segment (LLS) to total liver volume (TLV) were measured from the same multiphasic liver CT examinations. Accuracy for differentiating cirrhotic from noncirrhotic livers was assessed by area under the receiver operating characteristic curve. Intra- and interobserver agreement was assessed by intraclass correlation coefficient. Results Median LSN scores from nonenhanced thick-section CT images in cirrhotic livers (3.16; 56 livers) were significantly higher than in noncirrhotic livers (2.11; 38 livers; P < .001). LSN scores from the four CT imaging types (94 patients for each type) were very strongly correlated (range of Spearman r, 0.929-0.960). LSN scores from portal venous phase contrast-enhanced thick-section CT images had significantly higher accuracy (area under the receiver operating characteristic curve, 0.929) than splenic volume (area under the receiver operating characteristic curve, 0.835) or LLS-to-TLV ratio measurements (area under the receiver operating characteristic curve, 0.753) for differentiating cirrhotic from noncirrhotic livers (P = .038 and .003, respectively; n = 94). Intra- and interobserver agreements that used nonenhanced thick CT images were very good (intraclass correlation coefficient, 0.963 and 0.899, respectively). Conclusion Quantitative measurement of LSN on routine CT images accurately differentiated cirrhotic from noncirrhotic livers and was highly reproducible. (©) RSNA, 2016 Online supplemental material is available for this article.

Prediction of pancreatic fistula and fibrosis in patients undergoing pancreatic resections using differential pancreatic enhancement pattern on multiphasic computed tomography (MPCT) scan: a prospective study

Prediction of pancreatic fistula and fibrosis in patients undergoing pancreatic resections using differential pancreatic enhancement pattern on multiphasic computed tomography (MPCT) scan: a prospective study

Pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms (NEN) account for 1-2% of all pancreatic neoplasms and represent a rare differential diagnosis. While some pancreatic NEN are hormonally active and exhibit endocrine activity associated with characteristic symptoms, the majority are hormonally inactive. Imaging techniques such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) or as combined PET/CT play a crucial role in the initial diagnosis, therapy planning and control. Endoscopic ultrasound (EUS) and multiphase CT represent the reference methods for localization of the primary pancreatic tumor. Particularly in the evaluation of small liver lesions MRI is the method of choice. Somatostatin receptor scintigraphy and somatostatin receptor PET/CT are of particular value for whole body staging and special aspects of further therapy planning.

CT findings of adrenal schwannoma

To analyse the computed tomography (CT) imaging features of patients with adrenal schwannoma. Eight cases of adrenal schwannoma confirmed by histopathology were included in this study. All eight patients had undergone multiphase CT examinations. The features of the adrenal schwannoma in the CT images were analysed retrospectively in detail, including size, shape, margin, radiodensity, calcification, and enhancement pattern. There were six male and two female patients, with a median age of 44.5 years (range, 25-52 years). Two patients complained of right flank pain, and two with left upper abdominal discomfort, while the remaining patients were diagnosed by routine ultrasound examinations. On unenhanced CT images, all cases of adrenal schwannoma were well circumscribed, rounded or oval, heterogeneous masses with cystic components, with two cases exhibiting calcification, and three cases with septa. On enhanced CT images, all cases displayed mild heterogeneous enhancement of the tumour during the arterial phase, and progressive enhancement during the portal venous phase and equilibrium phase. Adrenal schwannoma commonly presents as a well-defined unilateral mass with cystic degeneration, septa, and a characteristic progressive contrast-enhancement pattern on multiphase enhanced scans.

Abstract WP23: Clot Burden and Collateral Flow on Multiphase CT: Predictor of Outcomes After Recanalization Therapy in Acute Middle Cerebral Artery Infarction

Introduction and Hypothesis: We evaluated the ability of mixed grading system based on thrombus burden and collateral status assessed by multiphase computed tomography (MPCT) as a predictor of outcome after recanalization therapy. Methods: Eighty-six consecutive patients who underwent MPCT for acute M1 middle cerebral artery occlusion within 6 hours of symptom onset were included. Collateral status to the occluded MCA territory was classified as follows: grade 1, no collaterals; grade 2, slow collaterals with persistence of defect; Grade 3, slow but complete collateral; grade 4, rapid complete collateral. A grade of 1-2 was designated as poor, 3-4 as good collateral flow. Short clot segment was defined as contrast filling defect length on MPCT &lt; 1 centimeter. We divided patients into 3 groups based on collateral status and clot segment length: good collateral with short clot segment (N=29), good collateral with long clot segment (N=34), poor collateral (N=23). Results: Clinical characteristics were not different between 3 groups. Good functional outcome (3 months modified Rankin scale scores ≤ 2) and major neurologic improvement (1 day NIHSS score improved to 0 or 1 point or &gt; 8 points decrease from baseline) were more frequent for short clot segment group and good collateral group than poor collateral group. In logistic regression, after adjusting other variables, good collateral and short clot segment were independent predictors for good functional outcome compared poor collateral (good collateral: OR 12.117, p=0.013; short clot segment with good collateral: OR 44.418, p=0.003). Similarly, the major neurologic improvement was significantly related with good collateral and short segment group. (good collateral: OR 8.903, p=0.41; short clot segment with good collateral: OR 40.430, p=0.006) Conclusions: Short clot segment and good collateral flow assessed with MPCT were useful additional markers predicting clinical outcomes after recanalization therapy.

Tumor angiogenesis-related parameters in multi-phase enhanced CT correlated with outcomes of hepatocellular carcinoma patients after radical hepatectomy

PurposeTo determine if the prognosis of hepatocellular carcinoma (HCC) patients after radical hepatectomy may be indicated by the degree and pattern of contrast enhancement on preoperative computed tomography (CT) scan of the tumor. MaterialsThe degree and patterns of enhancement of HCC tumor images were retrospectively reviewed of 87 HCC patients who underwent preoperative contrast-enhanced CT prior to radical hepatectomy. The patients' conditions and outcomes were followed after surgery. The Kaplan–Meier method and log-rank test were used for univariate survival analysis. The Cox proportional hazard method was performed for multivariate analysis. ResultsThe 1- and 3-year cumulative survival rates of this cohort were 78% and 57%, respectively. The univariate analyses showed that risk factors contributing to survival were, in the arterial phase, the degree of tumor enhancement (A-dTE), tumor-to-aortic ratio (A-T/A), and tumor-to-liver CT value ratio (A-T/L); and in the portal venous phase, the tumor-to-aortic ratio (P-T/A), and tumor-to-liver ratio (P-T/L). Further multivariable Cox analysis revealed that the A-T/A (P = 0.020) and P-T/L (P = 0.045) were, independently, significant factors related to the survival rate. A-T/A <0.25, P-T/L <0.85, or both predicted a poor outcome for HCC patients after radical hepatectomy. ConclusionsPreoperative multi-phase contrast-enhanced CT parameters could be helpful in the prognosis of HCC patents after radical hepatectomy.

Evolving management of insulinoma: Experience at a tertiary care centre.

Background & objectives:Since our previous study in 2006, several new modalities for localization of cause of endogenous hyperinsulinemic hypoglycaemia such as multiphasic computed tomography (CT), multiphasic magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), intraoperative ultrasound, and intra-arterial calcium infusion with arterial stimulation venous sampling (ASVS) have become available. Therefore, to evaluate the relative usefulness of various imaging modalities to guide future management in terms of diagnosis and patient care, we analyzed presentation and management of patients of endogenous hyperinsulinemic hypoglycaemia.Methods:In this retrospective study, medical records of patients admitted with endogenous hyperinsulinemic hypoglycaemia were retrieved. Data pertaining to clinical features, diagnosis, imaging, surgery and patient outcome were extracted. The localization of insulinoma by preoperative imaging techniques was compared with the findings at surgery to assess the accuracy of localization.Results:Fasting hypoglycaemia was present in all, and post-prandial hypoglycaemia (plasma glucose ≤50 mg/dl within four hours of meal) in 25.8 per cent. Mean duration of symptoms before reaching a diagnosis of hyperinsulinemic hypoglycaemia was 3.9 years. Mean duration of provocative fast was 21.8 h (range 6-48 h). Among the currently used imaging modalities, the sensitivity of localizing tumour was 79.3 per cent for multiphasic CT, 85 per cent for multiphasic MRI and 95 per cent for EUS. EUS detected tumour missed by both CT and MRI. All, except one of the operated patients, were cured by surgery.Interpretation & conclusions:Our results suggest that patients with insulinoma have a varied presentation. Multiphasic contrast-enhanced MRI/CT scan, EUS and ASVS may be complimentary in pre-operative localization.

Optimal scan delay depending on contrast material injection duration in abdominal multi-phase computed tomography of pancreas and liver in normal Beagle dogs.

This study was conducted to establish the values for optimal fixed scan delays and diagnostic scan delays associated with the bolus-tracking technique using various contrast material injection durations in canine abdominal multi-phase computed tomography (CT). This study consisted of two experiments employing the crossover method. In experiment 1, three dynamic scans at the porta hepatis were performed using 5, 10 and 15 sec injection durations. In experiment 2, two CT scans consisting of five multi-phase series with different scan delays of 5 sec intervals for bolus-tracking were performed using 5, 10 and 15 sec injection duration. Mean arrival times to aortic enhancement peak (12.0, 15.6, and 18.6 sec for 5, 10, and 15 sec, respectively) and pancreatic parenchymal peak (17.8, 25.1, and 29.5 sec) differed among injection durations. The maximum mean attenuation values of aortas and pancreases were shown at the scan section with 0 and 5, 0 and 10 and 5 and 10 sec diagnostic scan delays during each injection duration, respectively. The optimal scan delays of the arterial and pancreatic parenchymal phase in multi-phase CT scan using fixed scan delay or bolus-tracking should be determined with consideration of the injection duration.

A Survey of Pediatric CT Protocols and Radiation Doses in South Korean Hospitals to Optimize the Radiation Dose for Pediatric CT Scanning.

Children are at greater risk of radiation exposure than adults because the rapidly dividing cells of children tend to be more radiosensitive and they have a longer expected life time in which to develop potential radiation injury. Some studies have surveyed computed tomography (CT) radiation doses and several studies have established diagnostic reference levels according to patient age or body size; however, no survey of CT radiation doses with a large number of patients has yet been carried out in South Korea.The aim of the present study was to investigate the radiation dose in pediatric CT examinations performed throughout South Korea.From 512 CT (222 brain CT, 105 chest CT, and 185 abdominopelvic CT) scans that were referred to our tertiary hospital, a dose report sheet was available for retrospective analysis of CT scan protocols and dose, including the volumetric CT dose index (CTDIvol), dose-length product (DLP), effective dose, and size-specific dose estimates (SSDE).At 55.2%, multiphase CT was the most frequently performed protocol for abdominopelvic CT. Tube current modulation was applied most often in abdominopelvic CT and chest CT, accounting for 70.1% and 62.7%, respectively. Regarding the CT dose, the interquartile ranges of the CTDIvol were 11.1 to 22.5 (newborns), 16.6 to 39.1 (≤1 year), 14.6 to 41.7 (2–5 years), 23.5 to 44.1 (6–10 years), and 31.4 to 55.3 (≤15 years) for brain CT; 1.3 to 5.7 (≤1 year), 3.9 to 6.8 (2–5 years), 3.9 to 9.3 (6–10 years), and 7.7 to 13.8 (≤15 years) for chest CT; and 4.0 to 7.5 (≤1 year), 4.2 to 8.9 (2–5 years), 5.7 to 12.4 (6–10 years), and 7.6 to 16.6 (≤15 years) for abdominopelvic CT. The SSDE and CTDIvol were well correlated for patients <5 years old, whereas the CTDIvol was lower in patients ≥6 years old.Our study describes the various parameters and dosimetry metrics of pediatric CT in South Korea. The CTDIvol, DLP, and effective dose were generally lower than in German and UK surveys, except in certain age groups.

Impact of intravenous contrast enhancement phase on target definition for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHC): Observations from patients enrolled on a prospective phase 2 trial

BackgroundThe safety and efficacy of radiation therapy for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHC) depend on accurate definition of gross tumor volume (GTV), but GTV often varies between phases of multiphasic computed tomography (CT) imaging. MethodsWe contoured GTVs on arterial, portal venous, and delayed phases of multiphasic CT scans for 32 patients treated on an institutional review board–approved prospective trial of proton therapy for primary liver tumors and determined which phase provided optimal GTV visualization. We assessed agreement between individual phase GTVs to determine if GTV for each phase was encompassed in a 5-mm expansion of either the smallest or the best-visualized GTV. ResultsThere were 19 HCC lesions and 14 IHC lesions. HCC lesions were best identified on the arterial phase in 42% (n = 8), portal venous phase in 32% (n = 6), and delayed phase in 26% (n = 5). IHC lesions were best identified on portal venous phase in 64% (n = 9) and the arterial phase in 29% (n = 4), with 1 case equally visualized on arterial and portal venous phases. In all 33 lesions, a 5-mm expansion around the smallest GTV failed to cover GTVs defined on other available phases. A 5-mm expansion around the best-visualized GTV provided satisfactory coverage of all available phases’ GTVs in 6/18 HCC cases and 2/9 IHC cases. ConclusionsVariability between GTVs on multiphasic CT scans could not be overcome with a 5-mm expansion of either the smallest GTV or the best-visualized GTV. Assessment of all available intravenous contrast phases is essential to accurately define the GTV.

Imaging Predictors of Elevated Lung Shunt Fraction in Patients Being Considered for Yttrium-90 Radioembolization

PurposeTo identify imaging findings associated with elevated lung shunt fraction (LSF) in patients being considered for yttrium-90 (90Y) radioembolization. Materials and MethodsDuring the period 2009–2014, 152 consecutive patients underwent planning hepatic arteriography with technetium-99m (99mTc) macroaggregated albumin (MAA) injection. Computed tomography (CT) or magnetic resonance imaging performed before the procedure for each patient was assessed for hepatic vein (HV) tumor thrombus or occlusion from external compression by tumor. When imaging was a multiphase CT scan (117 patients), the arterial phase was evaluated for evidence of early HV opacification (relative to unaffected HVs), indicating hepatic venous shunting. These factors were correlated with LSF determined by 99mTc-MAA imaging. ResultsMedian LSF was 6.7% (range, < 0.1%–71%), significantly higher for HCC (8.0% vs 6.3% for other tumors, P = .048). Larger tumor size was associated with higher LSF in univariate analysis (P = .001). There was high interobserver agreement for determining hepatic venous shunting (97%, κ = 0.847), which was associated with higher LSF (P < .001; 78% sensitivity, 93% specificity). Of 5 cases of HV tumor thrombus, all had high (> 20%) LSF (P < .001). HV occlusion was also associated with higher LSF (P = .039). Multivariate analysis confirmed that early HV opacification and either HV tumor thrombus or occlusion were associated with higher LSF. ConclusionsEarly HV opacification and HV tumor thrombus or occlusion on cross-sectional imaging performed before radioembolization are associated with elevated LSF, which may contraindicate or limit the dose delivered in 90Y radioembolization. This information could be helpful during patient counseling for anticipating the most appropriate mode of liver-directed therapy.

Transcatheter arterial chemoembolization combined with CT-guided percutaneous thermal ablation versus hepatectomy in the treatment of hepatocellular carcinoma.

IntroductionTranscatheter arterial chemoembolization (TACE) plus thermal ablation has been widely used recently in the treatment of hepatocellular carcinoma (HCC). In this study, we aimed to compare results of the combination of TACE and percutaneous thermal ablation with those of hepatectomy in patients with HCC.MethodsThe clinical data of 137 HCC patients who sequentially received TACE and computed tomography (CT)-guided percutaneous thermal ablation as an initial curative treatment (combination group) and 148 matched HCC patients who received hepatectomy (surgery group) between 2004 and 2011 were collected and analyzed. After TACE, multiphase contrast-enhanced CT was performed to identify the total number of tumors as well as lipiodol deposition in the liver. Survival was calculated by using the Kaplan-Meier method and compared by using the log-rank test. The prognostic factors were assessed with multivariate Cox proportional hazards regression analysis.ResultsOf all 285 patients, 225 (79.0 %) had cancerous lesions ≤ 5 cm in diameter. In preoperative contrast-enhanced CT or magnetic resonance imaging, the number of tumors was 1–4 for each patient. The 1-, 3-, and 5-year overall survival rates were 95, 74 %, and 67 % in the combination group and 88, 66, and 47 % in the surgery group, respectively (P = 0.004); the corresponding recurrence-free survival rates for the two groups were 92, 69, and 61 % and 75, 58, and 44 %, respectively (P = 0.001). In the multivariate analysis, treatment allocation was an independent prognostic factor for survival. Only 60 patients in the combination group had sufficient imaging data, and 135 new lesions with lipiodol deposition were diagnosed as malignancies in 22 of 60 patients, whereas 20 new lesions were found in 11 of 148 patients in the surgery group.ConclusionThe combination of TACE and CT-guided percutaneous thermal ablation for HCC improves survival of HCC patients compared with hepatectomy.

Estimation of hepatic extracellular volume fraction using multiphasic liver computed tomography for hepatic fibrosis grading.

The purpose of this study was to determine whether hepatic extracellular volume fractions (fECVs) measured using multiphasic liver computed tomography (CT) can be used to quantify the severity of hepatic fibrosis (HF). This retrospective study was approved by our institutional review board, and the requirement for informed consent was waived. A total of 141 patients (male-female ratio, 109:32; mean [SD] age, 59.4 [11.4] years) histologically diagnosed with HF (F0-F1 = 33 and F2-F4 = 108) underwent multiphasic liver CT. Absolute enhancements (in Hounsfield unit) of the liver parenchyma (Eliver) and aorta (Eaorta) 3 minutes after contrast administration were measured on subtraction images of precontrast and equilibrium phase scans using nonrigid registration software. The fECV was calculated using the following equation: fECV (%) = Eliver/Eaorta × (100 - Hematocrit [%]). Correlation between fECV and HF stage was evaluated using the Spearman correlation coefficient. The fECVs were compared between F0-F1 and ≥F2 as well as between child A and child B or C. Diagnostic performance of fECV in predicting significant HF (≥F2) was assessed using receiver operating curve analysis. The fECVs showed a significant correlation with pathologic HF staging (r = 0.493, P < 0.001). The F2-F4 showed significantly higher fECVs than did F0 to F1 (33.6% [4.7%] vs 27.7% [4.4%]; P < 0.001). The fECVs were significantly higher in the patients with child B or C than those with child A (35.2% [7.0%] vs 31.3% [4.2%]; P < 0.001). The fECV values higher than 28.76% provided 87.5% sensitivity and 71.0% specificity in detecting significant HF (area under the curve, 0.832; P < 0.0001). Because fECV was shown to increase along with HF progression, the estimation of fECV using routine multiphasic liver CT may have the potential to detect significant HF.

Do we really need additional contrast-enhanced abdominal computed tomography for differential diagnosis in triage of middle-aged subjects with suspected biliary pain.

Enhanced computed tomography (CT) is widely used for evaluating acute biliary pain in the emergency department (ED). However, concern about radiation exposure from CT has also increased. We investigated the usefulness of pre-contrast CT for differential diagnosis in middle-aged subjects with suspected biliary pain.A total of 183 subjects, who visited the ED for suspected biliary pain from January 2011 to December 2012, were included. Retrospectively, pre-contrast phase and multiphase CT findings were reviewed and the detection rate of findings suggesting disease requiring significant treatment by noncontrast CT (NCCT) was compared with cases detected by multiphase CT.Approximately 70% of total subjects had a significant condition, including 1 case of gallbladder cancer and 126 (68.8%) cases requiring intervention (122 biliary stone-related diseases, 3 liver abscesses, and 1 liver hemangioma). The rate of overlooking malignancy without contrast enhancement was calculated to be 0% to 1.5%. Biliary stones and liver space-occupying lesions were found equally on NCCT and multiphase CT. Calculated probable rates of overlooking acute cholecystitis and biliary obstruction were maximally 6.8% and 4.2% respectively. Incidental significant finding unrelated with pain consisted of 1 case of adrenal incidentaloma, which was also observed in NCCT.NCCT might be sufficient to detect life-threatening or significant disease requiring early treatment in young adults with biliary pain.

Computer tomography imaging findings of adrenal cavernous hemangiomas: a report of 10 cases.

Cavernous hemangiomas (CHs) of the adrenal gland are extremely rare. To date, only a few studies of adrenal CH imaging have been reported. To analyze the computed tomography (CT) imaging findings of adrenal CHs. Ten cases of adrenal CHs confirmed by a histopathological examination were retrospectively analyzed. All of the patients had undergone unenhanced and enhanced CT examinations, and eight had also undergone multiphase CT enhancement examinations. CT characteristics, including shape, size, margin, attenuation, and enhancement patterns, were analyzed. The study included six women and four men with a mean age of 49.2 years (age range, 25-62 years) and no signs of abnormal endocrine activity. The unenhanced CTs showed well-defined, heterogeneous (n = 8) or homogeneous (n = 2) density masses with scattered (n = 8) or spread calcifications (n = 2) in six tumors. In the contrast-enhanced CTs, seven tumors appeared to be marked with heterogeneous enhancement, whereas three cases exhibited no obvious enhancement. The evaluation of the pattern of dynamic enhancement in eight patients revealed that the tumors showed early peripheral enhancement (n = 4), early central enhancement (n = 1), and mixed enhancement (n = 1) with progressive partial filling-in, and no obvious enhancement in any phases (n = 2). Adrenal CHs should be included in the differential diagnosis when an adrenal neoplasm is incidentally found and appears as a well-defined, heterogeneous mass with calcifications and various enhancement patterns, including heterogeneous enhancement with characteristic progressive partial filling-in, as well as lack of enhancement in any phase.

Establishment of optimal scan delay for multi-phase computed tomography using bolus-tracking technique in canine pancreas.

To establish a protocol for a multi-phase computed tomography (CT) of the canine pancreas using the bolus-tracking technique, dynamic scan and multi-phase CT were performed in six normal beagle dogs. The dynamic scan was performed for 60 sec at 1-sec intervals after the injection (4 ml/sec) of a contrast medium, and intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were measured. The multi-phase CT with 3 phases was performed three times using a bolus-tracking technique. Scan delays were 0, 15 and 30 in first multi-phase scan; 5, 20 and 35 in second multi-phase scan; and 10, 25 and 40 sec in third multi-phase scan, respectively. Attenuation values and contrast enhancement pattern were analyzed from the aorta, pancreas and portal vein. The intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were 3.8 ± 0.7, 8.7 ± 0.9 and 13.3 ± 1.5 sec, respectively. The maximum attenuation values of the aorta, pancreatic parenchyma and portal vein were present at scan sections with no scan delay, a 5-sec delay and a 10-sec delay, respectively. When a multi-phase CT of the canine pancreas is triggered at aortic enhancement appearance using a bolus-tracking technique, the recommended optimal delay times of the arterial and pancreatic parenchymal phases are no scan delay and 5 sec, respectively.