Hepatospecific MR contrast agent uptake on hepatobiliary phase can be used as a biomarker of marked ß-catenin activation in hepatocellular adenoma.

OBJECTIVES: To assess the value of hepatospecific MR contrast agent uptake on hepatobiliary phase (HBP) images to detect marked activation of the ß-catenin pathway in hepatocellular adenomas (HCAs). METHODS: This multicentric retrospective IRB-approved study included all patients with a pathologically proven HCA who underwent gadobenate dimeglumine-enhanced liver MRI with HBP. Tumor signal intensity on HBP was first assessed visually, and lesions were classified into three distinct groups-hypointense, isointense, or hyperintense-according to the relative signal intensity to liver. Uptake was then quantified using the lesion-to-liver contrast enhancement ratio (LLCER). Finally, the accuracy of HBP analysis in depicting marked ß-catenin activation in HCA was evaluated. RESULTS: A total of 124 HCAs were analyzed including 12 with marked ß-catenin activation (HCA B+). Visual analysis classified 94/124 (76%), 12/124 (10%), and 18/124 (14%) HCAs as being hypointense, isointense, and hyperintense on HBP, respectively. Of these, 1/94 (1%), 3/12 (25%), and 8/18 (44%) were HCA B+, respectively (p < 0.001). The LLCER of HCA B+ was higher than that of HCA without marked ß-catenin activation in the entire cohort (means 4.9 ± 11.8% vs. - 19.8 ± 11.4%, respectively, p < 0.001). A positive LLCER, i.e., LLCER ≥ 0%, had 75% (95% CI 43-95%) sensitivity and 97% (95% CI 92-99%) specificity, with a LR+ of 28 (95% CI 8.8-89.6) for the diagnosis of HCA B+. CONCLUSIONS: Hepatospecific contrast uptake on hepatobiliary phase is strongly associated with marked activation of the ß-catenin pathway in hepatocellular adenoma, and its use might improve hepatocellular adenoma subtyping on MRI. KEY POINTS: • Tumor uptake on hepatobiliary phase in both the visual and quantitative analyses had a specificity higher than 90% for the detection of marked ß-catenin activation in hepatocellular adenoma. • However, the sensitivity of visual analysis alone is inferior to that of LLCER quantification on HBP due to the high number of HCAs with signal hyperintensity on HBP, especially those developed on underlying liver steatosis.

Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres.

PURPOSE: To compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus 99mTc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using 90Y-glass microspheres. MATERIALS AND METHODS: Fifteen patients (8 men, 7 women) with a mean age of 68.3±10.5 (SD) years (range: 47-82 years) who underwent a total of 17 SIRT procedures using 90Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from 99mTc-MAA SPECT/CT using either CBCT or 99mTc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using 90Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (DT), non-tumoral liver, perfused liver (DPL) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρc values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland-Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing-Bablok regression. RESULTS: The intra- and interobserver reliabilities were good-to-excellent (ρc: 0.80-0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8Gy (IQR: -12.7; 16.1) and 5.6Gy (IQR: -13.6; 10.2) for DPL-CBCT and DPL-99mTc-MAA SPECT/CT, respectively. The median differences were 1.6Gy (IQR: -29; 7.53) and 9.8Gy (IQR: -28.4; 19.9) for DT-CBCT and DT-99mTc-MAA SPECT/CT respectively. Passing-Bablok regression analysis showed that both CBCT and 99mTc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate DT and DPL at higher post-treatment doses. CONCLUSION: CBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of 99mTc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers.

Point-shear wave elastography predicts liver hypertrophy after portal vein embolization and postoperative liver failure.

PURPOSE: To correlate point-shear wave elastography (SWE) with liver hypertrophy after right portal vein embolization (RPVE) and to determine its usefulness in predicting postoperative liver failure in patients undergoing partial liver resection. PATIENTS AND METHODS: Point-SWE was performed the day before RPVE in 56 patients (41 men) with a median age of 66 years. The percentage (%) of future remnant liver (FRL) volume increase was defined as: %FRLpost-%FRLpre%FRLpre×100 and assessed on computed tomography performed 4 weeks after RPVE. RESULTS: Median (range) %FRLpre and %FRLpost was respectively, 31.5% (12-48%) and 41% (23-61%) (P<0.001), with a median %FRL volume increase of 25.6% (-8; 123%). SWE correlated with %FRL volume increase (P=-0.510; P<0.001). SWV (P=0.003) and %FRLpre (P<0.001) were associated with %FRL volume increase at multivariate regression analysis. Forty-three patients (77%) were operated. Postoperative liver failure occurred in 14 patients (32.5%). Median SWE was different between the group with (1.68m/s) and without liver failure (1.07m/s) (P=0.018). The AUROC of SWE predicting liver failure was 0.724 with a best cut-off of 1.31m/s, corresponding to a sensitivity of 21%, specificity of 96%, positive predictive value 75% and negative predictive value of 72%. SWE was the single independent preoperative variable associated with liver failure. CONCLUSIONS: SWE assessed by point-SWE is a simple and useful tool to predict the FRL volume increase and postoperative liver failure in a population of patients with liver tumor.

Radiological evaluation of response to neoadjuvant treatment in pancreatic cancer.

Neoadjuvant chemotherapy has become common practice in the management of patients with non-metastatic pancreatic adenocarcinoma. This strategy helps better select patients who would benefit from surgical resection and also increase the number of patients amenable to surgical resection whose tumor seemed too locally advanced on initial imaging. However, several studies have shown that the radiological evaluation of the response after neoadjuvant therapy is difficult for pancreatic carcinoma. This article reviews the scientific basis of neoadjuvant therapy for non-metastatic pancreatic cancer and provides an update on tumor response evaluation with imaging after neoadjuvant treatment.

Short- and long-term evolution of the endoluminal diameter of underdilated stents in transjugular intrahepatic portosystemic shunt.

PURPOSE: The purpose of this study was to evaluate the short- and long-term evolution of endoluminal diameter of covered metallic stents that were underdilated at the time of transjugular intrahepatic portosystemic shunt (TIPS) creation. MATERIEL AND METHODS: Sixteen patients (13 men, 3 women) with a mean age of 57.6years±7.9 (SD) were retrospectively included. All patients had had TIPS creation using a 10-mm diameter covered stent (VIATORR®) that was underdilated (i.e., 8mm) at the time of stent placement. Measurements of the mean circulating diameter of the stents were retrospectively performed on angiographic examinations every 6months up to 2years. RESULTS: The endoluminal stent diameter early enlarged from 8.96mm±1.12 (SD) to 10mm±1.45 (SD) after 6months (P=0.04) with no further significant changes over time after 12months (10.28mm±1.9mm), 18months (9.93±1.51mm) and 24months (9.92±0.9mm). CONCLUSION: Our results demonstrate a passive expansion of initially underdilated covered stents during the six months following TIPS creation. This should be taken into account regarding hepatic encephalopathy prevention during TIPS placement.

Pulmonary aspergilloma in a cavity formed after percutaneous radiofrequency ablation.

We report two cases of pulmonary aspergilloma (PA) in a cavity formed after percutaneous radiofrequency ablation (PRFA), a rare complication that has only been described once in the literature. The first patient was a 59-year-old white woman treated for a secondary lung nodule of an advanced hepatocellular carcinoma. One month after PRFA, a consolidation of a cavity was noticed with an "air crescent sign," and aspergilloma serology was highly positive. A bisegmentectomy was performed due to the proximity of the lesion to mediastinal vessels and the absence of significant regression after antifungal treatment. Histological examination confirmed the diagnosis of PA. The second patient was a 61-year-old white man followed-up for a non-small-cell lung cancer. A cavitation with thick margins in the ablation zone was noticed 6 months after PRFA. A biopsy was performed, and aspergilloma was diagnosed. Medical treatment with itraconazole was administered for 13 months, and there was significant regression.

Interest of contrast-enhanced sonography to identify focal nodular hyperplasia with sinusoidal dilatation.

BACKGROUND AND AIMS: Focal nodular hyperplasia with major sinusoidal dilatation (FNH-sd) is a misleading entity, with some features resembling inflammatory hepatocellular adenoma (HCA). We aimed to assess the performance of contrast-enhanced ultrasound (CEUS) for the diagnosis of FNH-sd. METHODS: Four histologically proven FNH-sd nodules in four patients were investigated with both MRI and CEUS imaging. Sinusoidal dilatation was focally visible in all cases in histology. RESULTS: In MRI, in all the four cases, lesions were hypervascular in arterial phase, with high intensity in T2-weighted sequence imaging and persistent enhancement in the delayed gadolinium-enhanced phase. These MRI features were more indicative of HCA than FNH. On the other hand, CEUS showed a very specific centrifugal filling followed by a strong, homogeneous enhancement of the whole lesion. CONCLUSION: CEUS seems to be an essential step for the diagnosis of non-typical FNH, such as FNH-sd. This small series highlights the interest of performing both CEUS and MRI for the diagnosis of atypical focal liver lesions, such as FNH-sd.

Ultrasound elastography in liver.

Conventional imaging techniques cannot provide information about tissue mechanical properties. Many injuries can cause changes in tissue stiffness, especially tumors and fibrosis. In recent years, various non-invasive ultrasound methods have been developed to study tissue elasticity for a large number of applications (breast, thyroid, prostate, kidneys, blood vessels, liver…). For non-invasive assessment of liver diseases, several ultrasound elastography techniques have been investigated: Transient elastography (the most extensively used), Real Time Elastography (RTE), Acoustic Radiation Force Impulse Imaging (ARFI) and more recently Shear Wave Elastography (SWE). Even if evaluation of liver fibrosis in chronic liver disease remains the principal application, there are many others applications for liver: predicting cirrhosis-related complications; monitoring antiviral treatments in chronic viral liver disease; characterizing liver tumors; monitoring local treatments, etc. The aim of this article is to report on the different hepatic ultrasound elastography techniques, their advantages and disadvantages, their diagnostic accuracy, their applications in clinical practice.

Volumetric feedback ablation of uterine fibroids using magnetic resonance-guided high intensity focused ultrasound therapy.

OBJECTIVE: The purpose of this prospective multicenter study was to assess the safety and technical feasibility of volumetric Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) ablation for treatment of patients with symptomatic uterine fibroids. METHODS: Thirty-three patients with 36 fibroids were treated with volumetric MR-HIFU ablation. Treatment capability and technical feasibility were assessed by comparison of the Non-Perfused Volumes (NPVs) with MR thermal dose predicted treatment volumes. Safety was determined by evaluation of complications or adverse events and unintended lesions. Secondary endpoints were pain and discomfort scores, recovery time and length of hospital stay. RESULTS: The mean NPV calculated as a percentage of the total fibroid volume was 21.7%. Correlation between the predicted treatment volumes and NPVs was found to be very strong, with a correlation coefficient r of 0.87. All patients tolerated the treatment well and were treated on an outpatient basis. No serious adverse events were reported and recovery time to normal activities was 2.3 ± 1.8 days. CONCLUSION: This prospective multicenter study proved that volumetric MR-HIFU is safe and technically feasible for the treatment of symptomatic uterine fibroids. KEY POINTS: • Magnetic-resonance-guided high intensity focused ultrasound allows non-invasive treatment of uterine fibroids. • Volumetric feedback ablation is a novel technology that allows larger treatment volumes • MR-guided ultrasound ablation of uterine fibroids appears safe using volumetric feedback.

[Evaluation of suspicious nipple discharge with MRI: review of 50 cases]. / Apport de l'IRM dans les écoulements mamelonnaires pathologiques: analyse de 50 cas.

PURPOSE: To determine the role of MRI in the evaluation and management of patients with suspicious nipple discharge and normal mammographic and US evaluation. PATIENTS AND METHODS: A total of 50 patients with suspicious nipple discharge and normal mammographic and US evaluation prospectively underwent MRI. The first 16 patients underwent routine breast MRI, while MR-ductography with image fusion at the console was added for the last 34 patients. RESULTS: In 22 of 25 high-risk and malignant lesions, MRI showed enhancement whereas it was normal in three cases. In 25 benign cases (resolution of discharge/benign non-proliferative breast disease), MRI was negative in 22 cases and falsely positive in three cases. CONCLUSION: In this clinical setting, MRI shows excellent sensitivity, PPV and NPV. A negative result on MRI would support clinical follow-up as opposed to surgery.

[Why and how to write and publish a paper in a radiology journal]. / Pourquoi et comment écrire et publier un article pour une revue radiologique.

Writing and publishing papers in radiology journals are mandatory for academic promotion and also contribute to the education of radiological community. The redaction of a scientific radiology paper is based on strict criteria that are also used by reviewers from the editorial board. In this article, the different steps in the construction and redaction of a radiology paper will be reviewed. Based on the collective experience of the authors, it is aimed at helping radiologists who wish to publish by increasing the likelihood of having their papers accepted by reviewers.

Molecular MR imaging and MR-guided ultrasound therapies in cancer.

Imaging in cancer has moved in the last twenty years from morphological detection of diseases to characterization and categorization of different subtypes of tumors. Functional information, based on dynamic contrast-enhanced imaging of tissue perfusion and evaluation of water diffusion, tissue oxygenation, capillary permeability or lymphatic drainage, plays a major role in that field.The next coming steps will concern the differentiation of biological behaviour of tumors according to their phenotypes by identifying specific surface receptors or products of synthesis.These developments allowing an in vivo identification of the tumor biological singularities is a tremendous progress in the management of cancer at the step of diagnosis but, more importantly, to assess the most appropriated treatment to each tumor type. At the same time, minimally invasive methods of treatment of tumors have also developed, mainly in the field of thermotherapies. Ablation of tumors using radiofrequency is now used in clinics as a new standard within the liver and as a promising additional option in many other organs as kidney, lung and bone. High intensity focused ultrasound (HIFU) showed more restricted developments in clinics, mainly applied to prostatic cancer, because of many technical barriers. We believe that magnetic resonance (MR) imaging and MR-guided HIFU (MRgHIFU) have a great potential in that field due to the capacity of MR imaging to monitor temperature changes for an optimal heat deposition and for an optimal safety. This technique has already gained recognition for the treatment of uterine leiomyomas. But it has still to prove its efficacy in treatment of malignant tumors. This review will focus on some recent developments in molecular characterisation of tumors using MR imaging and in technical improvements necessary for accurate application of MRgHIFU in cancer.

Liver fibrosis staging with contrast-enhanced ultrasonography: prospective multicenter study compared with METAVIR scoring.

We prospectively assessed contrast-enhanced sonography for evaluating the degree of liver fibrosis as diagnosed via biopsy in 99 patients. The transit time of microbubbles between the portal and hepatic veins was calculated from the difference between the arrival time of the microbubbles in each vein. Liver biopsy was obtained for each patient within 6 months of the contrast-enhanced sonography. Histological fibrosis was categorized into two classes: (1) no or moderate fibrosis (F0, F1, and F2 according to the METAVIR staging) or (2) severe fibrosis (F3 and F4). At a cutoff of 13 s for the transit time, the diagnosis of severe fibrosis was made with a specificity of 78.57%, a sensitivity of 78.95%, a positive predictive value of 78.33%, a negative predictive value of 83.33%, and a performance accuracy of 78.79%. Therefore, contrast-enhanced ultrasound can help with differentiation between moderate and severe fibrosis.

[Real-time contrast-enhanced ultrasound in the evaluation of focal liver lesions: diagnostic efficacy and economical issues from a French multicentric study]. / Echographie de contraste temps réel dans la prise en charge diagnostique des lésions nodulaires hépatiques: évaluation des performances diagnostiques et de l'impact économique sur une étude multicentrique française.

The recent introduction of high-end ultrasound equipment combined with recent contrast agents provides marked improvements in the characterization of focal liver lesions as previously reported by monocentric studies. The aim of the present study was to evaluate the diagnostic performance of Contrast-Enhanced Ultrasonography (CEUS) using SonoVue as well as its medico-economic value for characterization of focal liver lesions. These nodules were not characterized on previous CT or conventional sonography. This prospective multicentric study conducted in 15 French centres found diagnostic performances similar to those reported for CT and MRI, with a concordance rate of 84.5%, sensitivity greater than 80% and specificity greater than 90% for all types of lesions. Higher acceptance was found for CEUS compared to other imaging modalities. Economical assessment based on examination reimbursment and contrast agent cost showed a lower cost for contrast ultrasound versus CT and MRI. This French multicentric study confirmed the high diagnostic value of CEUS for focal liver lesion characterization and demonstrated a lower economical impact compared to other imaging modalities such as CT and MRI.