Typical Enhancement Pattern Research Articles

Dynamic enhancement pattern of HCC smaller than 3 cm in diameter on gadoxetic acid‐enhanced MRI: comparison with multiphasic MDCT

The dynamic enhancement pattern of HCCs smaller than 3 cm in diameter on gadoxetic acid-enhanced magnetic resonance imaging (MRI) have not been extensively investigated. We aimed to evaluate the dynamic enhancement patterns of small HCCs (≤3 cm) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and compare enhancement patterns with multiphasic multidetector computed tomography (MDCT) based on tumour cellular differentiation and size. We retrospectively included 55 patients with 67 surgically confirmed small HCCs (≤3 cm) who underwent multiphasic MDCT and gadoxetic acid-enhanced MRI. Dynamic enhancement patterns were analysed according to tumour cellular differentiation and size. Hepatobiliary phase images were also analysed to assess their additional value. The proportion of small HCCs demonstrating the typical enhancement pattern differed depending on tumour cellular differentiation on both MRI (P = 0.001) and MDCT (P = 0.001), but differed depending on tumour size only on CT (P = 0.008). Gadoxetic acid-enhanced MRI more sensitively depicted the typical enhancement pattern than CT for all tumours (P = 0.001), for moderately or poorly differentiated HCCs (P = 0.021) and for HCCs ≤2 cm (P = 0.001). 80% of tumours with atypical enhancement could be diagnosed as HCC based on tumour size and hepatobiliary phase images. On both gadoxetic acid-enhanced MRI and multiphasic CT, the dynamic enhancement patterns of small HCCs (≤3 cm) differed according to tumour cellular differentiation. Gadoxetic acid-enhanced MRI more frequently demonstrated the typical HCC enhancement pattern than CT in small HCCs.

Differential diagnosis of solid pancreatic lesions using contrast-enhanced three-dimensional ultrasonography

PurposeTo investigate the usefulness of contrast-enhanced three-dimensional ultrasonography (CE 3D US) for differential diagnosis of solid pancreatic lesions.MethodsEighty-five patients with solid pancreatic lesions who underwent CE 3D US were retrospectively analyzed. Sixty-four patients had pancreatic ductal adenocarcinoma (PDAC), 10 had mass-forming pancreatitis (MFP), and 11 had neuroendocrine tumor (NET). Two blinded readers evaluated the enhancement patterns using four features: vascularity in the arterial phase, vascularity in the venous phase, vessel location, and vessel form. Vascularity in both phases was classified as hypervascular, isovascular, or hypovascular. Vessel location was classified into peritumoral or intratumoral. Vessel form was classified into fine or irregular. Kappa values were used to assess inter-reader agreement. The institutional review board approved this study, and informed consent was obtained.ResultsKappa values of the four features were 0.75, 0.72, 0.85, and 0.65, which were graded as good or excellent. The most typical combined enhancement pattern in PDAC was hypovascularity in both phases with peritumoral and irregular vessels; MFP was isovascular in both phases with intratumoral and fine vessels; and NETs were hypervascular in both phases with intratumoral and irregular vessels. The sensitivity and positive predictive value of the three patterns were 93.8% and 96.7% for the PDAC pattern, 80.0% and 100% for the MFP pattern, and 81.8%, and 69.2% for the NET pattern, respectively. The accuracy of these diagnostic criteria was 90.5%.ConclusionCE 3D US allows detailed visualization of the enhancement patterns of various pancreatic lesions and can be used for the differential diagnosis.

Characterization of Focal Liver Lesions using Contrast Enhanced Ultrasound as a First Line Method: a Large Monocentric Experience

To present a large monocentric experience in the characterization of focal liver lesions (FLLs) using Contrast Enhanced Ultrasound (CEUS). A retrospective study was performed in the Gastroenterology and Hepatology Department, Timisoara, including 1100 patients with 1329 FLLs evaluated between September 2009 and January 2013. A CEUS examination was considered conclusive if the FLL respected the typical enhancement pattern as described in the EFSUMB Guidelines. From the 1329 FLLs, CEUS was conclusive for a specific pathology in 1102 cases (82.9%). For the differentiation of benign/malignant lesions, CEUS reached a conclusive diagnosis in 1196 (90%) cases. The percentage of conclusive CEUS examinations was significantly higher in patients without chronic liver disease as compared with those with chronic hepatopathies: 87.3% vs. 74.4% (p<0.0001). CEUS patterns of enhancement fell into clear cut specific diagnostic patterns in 83% of the FLLs discovered by US, and into clear cut benign versus malignant patterns in 90% of the cases. For this reason, we can strongly recommend CEUS as a first line imaging method to characterize FLLs found at US, at least in centers with a good experience in CEUS.

Small (≤1-cm) Hepatocellular Carcinoma: Diagnostic Performance and Imaging Features at Gadoxetic Acid–enhanced MR Imaging

To assess diagnostic performance and imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging in small (≤1-cm) hepatocellular carcinoma (HCC) detection in patients with chronic liver disease. The institutional review board approved this retrospective study and waived informed consent. Sixty patients (56 men, four women; mean age, 60.1 years) with HCC (146 lesions; 70 > 1 cm, 76 ≤ 1 cm) underwent gadoxetic acid-enhanced MR imaging. HCC was confirmed at surgical resection (72 lesions; 30 > 1 cm, 42 ≤ 1 cm) or by showing interval growth with typical enhancement patterns at follow-up dynamic computed tomography or MR imaging (74 lesions; 40 > 1 cm, 34 ≤ 1 cm). Two radiologists assessed MR imaging features and graded likelihood of HCC with a five-point confidence scale. Jackknife alternative free-response receiver operating characteristic (JAFROC) method was used. Mean JAFROC figure of merit for small HCC was 0.717; that for large (>1-cm) HCC was 0.973 with substantial agreement (κ = 0.676). Mean sensitivity and positive predictive value (PPV) were 46.0% (70 of 152) and 48.3% (70 of 145) for small HCC versus 95.0% (133 of 140) and 78.2% (133 of 170) for large HCC, respectively. Eleven of 76 small HCCs (14%) were not seen on MR images, even after careful investigation. MR imaging features of small HCC included arterial enhancement (79%, 60 of 76), hypointensity on hepatobiliary phase (HBP) images (68%, 52 of 76), washout on 3-minute delayed phase images (50%, 38 of 76), hyperintensity on T2-weighted images (43%, 33 of 76), hypointensity on T1-weighted images (32%, 24 of 76), and restriction on diffusion-weighted images (28%, 20 of 72). Arterial enhancement and washout on 3-minute delayed phase images or hypointensity on HBP images occurred in 66% of small HCCs (50 of 76). Diagnostic performance of gadoxetic acid-enhanced MR imaging for small HCC detection is still low, with mean sensitivity of 46.0% (70 of 152) and mean PPV of 48.3% (70 of 145). By adding hypointensity on HBP images as washout, diagnostic performance for small HCC detection can be improved.

Diagnostic Efficacy of Contrast‐Enhanced Sonography by Combined Qualitative and Quantitative Analysis in Breast Lesions

The purpose of this study was to evaluate the diagnostic efficacy of contrast-enhanced sonography for differentiation of breast lesions by combined qualitative and quantitative analyses in comparison to magnetic resonance imaging (MRI). Fifty-six patients with American College of Radiology Breast Imaging Reporting and Data System category 3 to 5 breast lesions on conventional sonography were evaluated by contrast-enhanced sonography and MRI. A comparative analysis of diagnostic results between contrast-enhanced sonography and MRI was conducted in light of the pathologic findings. Pathologic analysis showed 26 benign and 30 malignant lesions. The predominant enhancement patterns of the benign lesions on contrast-enhanced sonography were homogeneous, centrifugal, and isoenhancement or hypoenhancement, whereas the patterns of the malignant lesions were mainly heterogeneous, centripetal, and hyperenhancement. The detection rates for perfusion defects and peripheral radial vessels in the malignant group were much higher than those in the benign group (P < .05). As to quantitative analysis, statistically significant differences were found in peak and time-to-peak values between the groups (P < .05). With pathologic findings as the reference standard, the sensitivity, specificity, and accuracy of contrast-enhanced sonography and MRI were 90.0%, 92.3%, 91.1% and 96.7%, 88.5%, and 92.9%, respectively. The two methods had a concordant rate of 87.5% (49 of 56), and the concordance test gave a value of κ = 0.75, indicating that there was high concordance in breast lesion assessment between the two diagnostic modalities. Contrast-enhanced sonography provided typical enhancement patterns and valuable quantitative parameters, which showed good agreement with MRI in diagnostic efficacy and may potentially improve characterization of breast lesions.

Spectrum of Multilocular Cystic Hepatic Lesions: CT and MR Imaging Findings with Pathologic Correlation

A multilocular cystic hepatic lesion detected at computed tomography (CT) and magnetic resonance (MR) imaging is a common but nonspecific radiologic finding that can cause potential challenges for differential diagnosis. This imaging pattern may be observed in a wide spectrum of common and uncommon neoplastic or nonneoplastic entities. Neoplastic lesions include cystadenoma, cystadenocarcinoma, hepatocellular carcinoma (HCC), metastases, mesenchymal hamartoma, and inflammatory myofibroblastic tumor. Nonneoplastic lesions include hepatic abscess, echinococcal cyst, intrahepatic hematoma, and biloma. The multiple coalescent cysts seen in polycystic liver disease may exhibit an imaging pattern similar to that of a multilocular cystic lesion. Mural nodularity, irregular thickness of the septa, ragged inner surface, and typical enhancement pattern in the solid portion of the lesion are often indicative of malignancy, although multilocular primary or secondary malignant tumors are uncommon. Recognition of the more common necrosis or cystic change of HCC and metastases induced by locoregional or systemic treatment also is important. The nonenhanced cystic component may be composed of different types of fluids (eg, serous, mucinous, proteinaceous, hemorrhagic, bilious, or mixed) or spontaneous or treatment-related necrosis, whereas the septa may be formed by a wide range of tissues depending on the lesion type. An understanding of the CT and MR imaging findings of these lesions and their respective pathologic correlation aids in accurate diagnosis.

Enucleation of a five-kilograms hemangioma of the caudate lobe of the liver: A case report

Although cavernous hemangioma is the most common benign tumors of the liver, caudate lobe is rare site of this type of hepatic pathology. Owing to the intricacy of the anatomy of the caudate lobe, the reports on resection of whole caudate lobe for tumor inside were seldom seen before the 1980s. This segment of the liver was always considered as the forbidden zone of hepatic surgery. Although excision of the caudate lobe has been performed with other types of hepatic resection, isolated complete removal of the caudate lobe is a technically challenging procedure. We report a case of a giant cavernous hemangioma of the caudate lobe of the liver which extended to the right side compressing the right lobe.The patient was complaining of dull aching dragging abdominal pain in the right hypochondrium stationary in course for eight years, and in the last two years it became progressive preventing the patient from spleeping in supine position due severe dyspnea. Abdominal imaging, including ultrasonography and dynamic triphasic computed tomography (CT) scan showed a large mass in the caudate lobe with a typical CT enhancement pattern of a hemangioma. Surgical exploration and excision of the mass was done successfully and completely. The dimensions of the mass were 35x25x15 cm and the weight was 4750 g. Whatever the size of caudate lobe hemangioma, it could be enculated safely.

Role of contrast-enhanced ultrasound in follow-up assessment after ablation for hepatocellular carcinoma

To assess the usefulness of contrast-enhanced ultrasound (CEUS) during follow-up after percutaneous ablation therapy for hepatocellular carcinoma (HCC). A total of 141 patients with HCCs who received percutaneous ablation therapy were assessed by paired follow-up CEUS and contrast-enhanced computed tomography (CECT). The follow-up scheme was designed prospectively and the intervals between CEUS and CECT examinations were less than 14 d. Both images of follow-up CEUS and CECT were reviewed by radiologists. The ablated lesions were evaluated and classified as local tumor progression (LTP) and LTP-free. LTP was defined as regrowth of tumor inside or adjacent to the successfully treated nodule. The detected new intrahepatic recurrences were also evaluated and defined as presence of intrahepatic new foci. On CEUS and CECT, LTP and new intrahepatic recurrence both were displayed as typical enhancement pattern of HCC (i.e., hyper-enhancing during the arterial phase and washout in the late phase). With CECT as the reference standard, the ability of CEUS in detecting LTP or new intrahepatic recurrence during follow-up was evaluated. During a follow-up period of 1-31 mo (median, 4 mo), 169 paired CEUS and CECT examinations were carried out for the 141 patients. For a total of 221 ablated lesions, 266 comparisons between CEUS and CECT findings were performed. Thirty-three LTPs were detected on CEUS whereas 40 LTPs were detected on CECT, there was significant difference (P < 0.001). In comparison with CECT, the numbers of false positive and false negative LTPs detected on CEUS were 6 and 13, respectively; the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy of CEUS in detecting LTPs were 67.5%, 97.4%, 81.8%, 94.4% and 92.3%, respectively. Meanwhile, 131 new intrahepatic recurrent foci were detected on CEUS whereas 183 were detected on CECT, there was also significant difference (P < 0.05). In comparison with CECT, the numbers of false positive and false negative intrahepatic recurrences detected on CEUS were 13 and 65, respectively; the sensitivity, specificity, PPV, NPV and overall accuracy of CEUS in detecting new intrahepatic recurrent foci were 77.7%, 92.0%, 92.4%, 76.7% and 84.0%, respectively. The sensitivity of CEUS in detecting LTP and new intrahepatic recurrence after percutaneous ablation therapy is relatively low in comparison with CECT.

Histopathologically confirmed focal nodular hyperplasia of the liver: Gadoxetic acid-enhanced MRI characteristics

PurposeThe purpose of this study was to evaluate enhancement characteristics of histopathologically confirmed focal nodular hyperplasia (FNHs) with gadoxetic acid-enhanced MRI. Materials and MethodsTwenty-seven patients with all histopathologically proven FNHs were retrospectively identified. MRI consisted of T1- and T2-weighted (w) sequences with and without fat saturation (FS), multiphase dynamic T1-w images, and FS T1-w images during the hepatobiliary phase. Standard of reference was surgical resection (n=24) or biopsy (n=3). Images were analyzed for morphology and contrast behavior including signal intensity (SI) measurement on T1-w images normalized to the pre-contrast base line. ResultsIn total 36 FNHs were evaluated. All FNHs showed enhancement in the arterial phase, significant reduction contrast enhancement (“wash-out”) in the late dynamic phases was not present. In the hepatobiliary phase, all FNHs (100%) showed enhancement (overall SI increase, 118% (±91%), P<0.001) with at least partial hyperintensity to the liver. Upon visual comparison, 3 of 36 FNHs appeared with heterogeneous/partial enhancement (8%) and 7 (19%) showed rim-accentuated enhancement. ConclusionThe typical enhancement pattern of FNH with gadoxetic acid consists of arterial hyperperfusion, no wash-out during the venous phase, and at least partial hyperintensity compared to the liver in the hepatobiliary phase. Partial hypointensity or rim-accentuated enhancement rarely occurs.

CEUS in the differentiation between low and high-grade bladder carcinoma

IntroductionBladder cancer ranks 4th overall in the number of newly diagnosed cancers and 10th in causes of cancer deaths. More than 90% of all cases of bladder cancer are transitional cell carcinoma (TCC). The goal of this study is to confirm the usefulness of low mechanical index contrast-enhanced ultrasonography (CEUS), also in association with time–intensity curves, in the differentiation between high- and low-grade bladder malignant lesions. Materials and methodsFrom February 2006 to February 2012 we recruited 144 patients. All patients underwent grayscale ultrasonography (US), color-Doppler ultrasonography (CDUS) and contrast-enhanced ultrasonography (CEUS). Subsequently all patients underwent cystoscopy and TURB. ResultsHistological diagnoses were: 88 high-grade carcinomas (61.1%), and 56 low-grade carcinomas (38.9%). Sensitivity and specificity of CDUS were 87.5% (126/144) and 60%, respectively. Sensitivity and specificity of CEUS were 90.9% and 85.7%, respectively. Sensitivity and specificity of TIC were 91.6% (132/144) and 85.7%, respectively. Discussion and conclusionsCEUS is a reliable noninvasive method for differentiating low- and high-grade bladder carcinomas since it provides typical enhancement patterns as well as specific contrast-sonographic perfusion curves.

Enhancement patterns of hepatocellular carcinomas on multiphasic multidetector row CT: comparison with pathological differentiation

The objective of this study was to determine the incidence of typical and atypical enhancement patterns of hepatocellular carcinomas (HCCs) on multiphasic multidetector row CT (MDCT) and to correlate the enhancement patterns and morphological image findings of HCC with the degree of tumour differentiation. MDCT images of 217 patients with 243 surgically proven HCCs were evaluated through consensus reading by two radiologists. Our MDCT protocol was composed of precontrast, arterial, portal and delayed phases. The reviewers analysed the CT images for degree of attenuation; relative timing of washout; presence of dysmorphic intratumoral vessels, aneurysms and necrosis; tumour size; tumour margin; presence of pseudocapsule; intratumoral heterogeneity; and determined enhancement pattern. The imaging features were correlated with tumour differentiation using Fisher's exact test or the χ(2) test. Among 243 HCCs, 137 (56.4%) showed the typical enhancement pattern of HCC, which is arterial enhancement and washout on portal or equilibrium phase images. In the arterial phase, 190 of 243 (78.2%) HCCs showed hypervascularity, with approximately three quarters of poorly differentiated (PD) (34 of 45, 75.6%) and moderately differentiated (MD) HCCs (92 of 123, 74.8%) showing washout during the portal or delayed phases, vs only 50% of well-differentiated (WD) HCCs (11 of 22; p<0.048). The presence of intratumoral vessels and aneurysms, tumour necrosis, attenuation of precontrast, the relative timing of washout, intratumoral attenuation heterogeneity, tumour margin and tumour size were correlated with the pathological differentiation of HCCs (p<0.05). A typical enhancement of HCCs on MDCT was not unusual (43.6%) and WD and PD HCCs account for most of the atypical enhancement patterns. Early washout favoured MD and PD HCCs rather than WD HCCs, whereas in our study the presence of intratumoral aneurysm was a highly specific finding for PD HCC.

VH7 Contrast Enhanced EUS for the Differential Diagnosis of Pancreatic Mass

The differential diagnosis of pancreatic mass is frequently challenging even after all imaging modalities. Recently, contrast-enhanced endoscopic ultrasound (CE-EUS) was introduced into clinical medicine and it is possible to evaluate the dynamic enhancement of various lesions using this modality. However, the typical enhancement pattern of solid pancreatic mass is not well described. The aim of this study is to characterize the typical dynamic microvascular enhancement patterns of pancreatic mass according to histology.

Splenic Hemangiomas

The purpose of this study was to illustrate the baseline appearance and enhancement patterns of splenic hemangiomas on contrast-enhanced sonography. Two experienced radiologists retrospectively reviewed by consensus baseline and contrast-enhanced sonographic examinations of 27 patients (14 women and 13 men; mean age, 58.7 years) with 27 splenic hemangiomas (mean size, 2 cm) confirmed by splenectomy, biopsy, computed tomography, and magnetic resonance imaging and follow-up. On baseline sonography, 77.8% of the lesions showed a homogeneous echo texture that was mainly hyperechoic. Color Doppler imaging did not show any signal in 81.5% of the cases. After contrast agent injection, 59.2% of the splenic hemangiomas showed different degrees of contrast enhancement in the arterial phase followed by isoenhancement in the late parenchymal phase. Among these, 2 hemangiomas showed peripheral globular enhancement in the arterial phase, followed by progressive centripetal fill-in. In 29.6% of the cases, some degree of contrast enhancement was appreciable, but the hemangiomas remained substantially hypoechoic throughout the contrast-enhanced sonographic examinations, whereas in 11.1%, the combination of contrast enhancement in the arterial phase followed by wash-out in the late parenchymal phase was evident. Isoechogenicity to spleen parenchyma in all phases is the most frequent typical enhancement pattern of splenic hemangiomas observed on contrast-enhanced sonography. Nevertheless, these lesions may show atypical contrast enhancement patterns; therefore, further assessment with cross-sectional techniques is needed.

Development of a hepatocellular carcinoma in a chronic hepatitis C patient 18years after achieving a sustained virological response to interferon therapy: case report and literature review.

We report on a chronic hepatitis C patient who developed hepatocellular carcinoma (HCC) 18years after achieving a sustained virological response (SVR) to interferon therapy. We also review other reports of patients who developed HCC a long time after interferon therapy. The patient was a 67-year-old man with chronic hepatitis C who achieved an SVR to interferon therapy at the age of 49years in 1992. Eighteen years later, however, a tumor measuring 19mm in diameter in segment 7 of the liver was found by abdominal ultrasound. The tumor had a typical HCC enhancement pattern by dynamic computed tomography. A moderately to poorly differentiated HCC was confirmed by fine-needle aspiration biopsy. Fibrosis and inflammation in the liver parenchyma improved pathologically from F3A2 to F2A1 according to the New Inuyama Classification. Liver steatosis remained after achieving an SVR and the serum alanine aminotransferase level was persistently slightly elevated. The HCC was treated by transcatheter arterial chemoembolization combined with radiofrequency ablation. Patients with chronic hepatitis C who have achieved an SVR to interferon therapy, and those who have risk factors for the development of HCC, such as being male, of advanced age (<50 years is rare), or with progressive liver fibrosis and steatosis as a hepatic manifestation of metabolic syndrome, should undergo careful long-term follow-up.

Imaging features of small hepatocellular carcinomas with microvascular invasion on gadoxetic acid-enhanced MR imaging

ObjectivesDetection of hepatocellular carcinomas (HCCs) before microvascular invasion (MVI) occurs is important due to the poor outcomes associated with MVI. We retrospectively investigated the imaging features of small HCCs with MVI on gadoxetic acid-enhanced MR imaging. MethodsFifty patients (40 men and 10 women; mean age, 54 years) with 58 surgically proven small (2cm or less) HCCs were evaluated by gadoxetic acid-enhanced MRI. Signal intensities on imaging sequences and the presence of the typical dynamic enhancement pattern (arterial enhancement and washout) were assessed. Fisher's exact tests were performed to evaluate the relationships between the presence of MVI, tumor size, and imaging findings. ResultsNone of the 12 small HCCs with diameters of 1cm or less had MVI, while 15 (33%) of the 46 small HCCs with diameters of 1.1–2.0cm had MVI (p=0.025, Fisher's exact test). Among the small HCCs with diameters of 1.1–2.0cm, all HCCs with MVI showed the typical dynamic pattern and hyperintensity on T2- and diffusion-weighted images. Most HCCs (54 lesions, 93%) were hypointense on hepatobiliary phase images regardless of the presence of MVI. ConclusionsAll small HCCs with MVI showed typical dynamic pattern and hyperintensity on T2-weighted and diffusion-weighted images, while atypical dynamic pattern and size of less than 1cm in diameter may suggest absence of MVI.

Enhancement pattern of small hepatocellular carcinoma (HCC) at contrast-enhanced US (CEUS), MDCT, and MRI: Intermodality agreement and comparison of diagnostic sensitivity between 2005 and 2010 American Association for the Study of Liver Diseases (AASLD) guidelines

ObjectiveTo evaluate agreement between contrast-enhanced ultrasound (CEUS), multi-detector row computed tomography (MDCT) and magnetic resonance imaging (MRI) for the assessment of typical and atypical enhancement patterns of small hepatocellular carcinoma (HCC); and to compare diagnostic sensitivity of 2005 and 2010 American Association for the Study of Liver Diseases (AASLD) guidelines. Materials and methodsBetween January 2008 and December 2009, we included cirrhotic patients with newly diagnosed 10–20mm HCC imaged at two contrast-enhanced imaging techniques among CEUS, MDCT, and MRI. Dynamic studies were reviewed by two radiologists to assess enhancement pattern. Percentage of cases with concordant findings and Cohen coefficient (k) were calculated. McNemar's test was used to compare sensitivity between 2005 and 2010 AASLD guidelines. ResultsThere were 91 patients (69 M; 22 F; mean age, 68 years) with 96 HCCs, studied with a combination of CEUS and MDCT (n=59), CEUS and MRI (n=26), or MDCT and MRI (n=11). Intermodality agreement for assessment of tumor enhancement pattern was 67% (k=0.294, P=0.001). Typical enhancement pattern was detected coincidentally at two imaging modalities in 50 (52%) HCCs. Sensitivity for the diagnosis of HCC increased significantly using the 2010 AASLD (81/96 (84%) vs. 50/96 (52%), P<0.001). ConclusionsAgreement between two imaging modalities for the detection of typical tumor enhancement pattern was reached in 52% of cases. The 2010 AASLD guidelines significantly increased the sensitivity for the diagnosis of HCC.

Non‐invasive diagnostic criteria for hepatocellular carcinoma: The value of contrast washout at imaging and the death of alpha‐fetoprotein

Non‐invasive diagnostic criteria for hepatocellular carcinoma: The value of contrast washout at imaging and the death of alpha‐fetoprotein

Population-wide principal component-based quantification of blood–brain-barrier dynamics in multiple sclerosis

The processes by which new white matter lesions in multiple sclerosis (MS) develop are only partially understood. Much of this understanding has come through magnetic resonance imaging (MRI) of the human brain. One of the hallmarks of new lesion development in MS is enhancement on T(1)-weighted MRI scans following the intravenous administration of a gadolinium-based contrast agent that shortens the longitudinal relaxation time of the tissue. Visible enhancement on the MRI results from the opening of the blood-brain barrier and reveals areas of active inflammation. The incidence and number of existing enhancing lesions are common outcome measures used in MS treatment clinical trials. Dynamic-contrast-enhanced MRI (DCE-MRI) can estimate the rate at which contrast agents pass from the plasma to MS lesions. In this paper, we develop a principal component-based framework for the analysis of these data that provides biologically meaningful quantification of blood-brain-barrier opening in new MS lesions. To accomplish this, we use functional principal components analysis to study directions of variation in the voxel-level time series of intensities both within and across subjects. The analysis reveals and allows quantification of typical spatiotemporal enhancement patterns in acute MS lesions, providing measures of magnitude, rate, shape (ring-like vs. nodular), and dynamics (centrifugal vs. centripetal). Across 10 subjects with relapsing-remitting and primary progressive MS, we found subjects to have between 0 and 12 gadolinium-enhancing lesions, the majority of which enhanced centripetally. We quantified the spatiotemporal behavior within each of these lesions using novel measures. Further application of these techniques will determine the extent to which these lesion measures can predict or track response to therapy or long-term prognosis in this disorder.

Characterization and Diagnostic Confidence of Contrast-Enhanced Ultrasound for Solid Renal Tumors

The objective was to determine whether contrast-enhanced ultrasound (CEUS) could improve the diagnostic confidence of solid renal masses. CEUS examinations were performed on 51 patients with renal tumors. Histologic findings from surgical specimens ( n = 24) or magnetic resonance imaging follow-up ( n = 27) were used as reference procedures for definitive diagnosis. Diffuse heterogeneous/homogeneous enhancement and quick peripheralnodularenhancement were found to be characteristic patterns in renal cell carcinoma (RCC). Dotlike or diffuse heterogeneous/homogeneous enhancement and slow peripheral nodular enhancement were observed as typical enhancement patterns in angiomyolipoma. The results show that CEUS combined with conventional ultrasound significantly improves diagnostic confidence. The sensitivity for RCC diagnosis with this imaging approach was 86% and the specificity was 93%. Both positive and negative predictive values of detection were 90% and the overall accuracy was 90%.

Noninvasive diagnostic criteria for hepatocellular carcinoma in hepatic masses &gt;2 cm in a hepatitis B virus‐endemic area

Noninvasive criteria for diagnosing hepatocellular carcinoma (HCC) suggested by the American Association for the Study of Liver Diseases (AASLD) in 2005 consisted of serum α-fetoprotein (AFP) level >200 ng/ml or a typical enhancement pattern (arterial enhancement and portal/delayed washed out) on dynamic imaging of hepatic mass(es) >2 cm in a cirrhotic liver. To validate these criteria in a Korean population and to evaluate whether these criteria are applicable to patients without cirrhosis at a high risk of developing HCC. We prospectively investigated 206 consecutive patients with hepatic mass(es) >2 cm who underwent biopsy or surgical resection. Patients were evaluated by four-phase dynamic computed tomography (CT) and by assays of serum AFP concentrations at baseline. Patients were classified according to the presence of risk factors or cirrhosis, and the diagnostic accuracy of each test was determined. The positive predictive values (PPV) of typical CT findings or serum AFP >200 ng/ml were 97.8% in cirrhotic patients, 89.6% in high-risk patients without cirrhosis and 82.4% in low-risk patients. The PPVs of typical CT findings alone in these groups were 98.8, 97.6 and 87.5% respectively. In high-risk patients without cirrhosis, the addition of serum AFP levels to typical CT findings minimally increased the diagnostic sensitivity from 81.6 to 87.8% but reduced the PPV from 97.6 to 89.6%. Serum AFP concentration is not a suitable diagnostic criterion for HCC. Typical CT findings can be used to diagnose HCC >2 cm both in cirrhotic patients and in high-risk patients without cirrhosis.