Laurence Baranes

Intravoxel incoherent motion (IVIM) MR imaging of colorectal liver metastases: Are we only looking at tumor necrosis?

To determine if intra‐voxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) parameters, including free molecular‐based (D) and perfusion‐related (D*, f) diffusion parameters, correlate with the degree of tumor necrosis and viable tumor in colo‐rectal cancer (CRC) metastasis.

Whole-Body Diffusion-weighted Imaging in Hodgkin Lymphoma and Diffuse Large B-Cell Lymphoma.

Whole-body imaging, in particular molecular imaging with fluorine 18 ((18)F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), is essential to management of lymphoma. The assessment of disease extent provided by use of whole-body imaging is mandatory for planning appropriate treatment and determining patient prognosis. Assessment of treatment response allows clinicians to tailor the treatment strategy during therapy if necessary and to document complete remission at the end of treatment. Because of rapid technical developments, such as echo-planar sequences, parallel imaging, multichannel phased-array surface coils, respiratory gating, and moving examination tables, whole-body diffusion-weighted (DW) magnetic resonance (MR) imaging that reflects cell density is now feasible in routine clinical practice. Whole-body DW MR imaging allows anatomic assessment as well as functional and quantitative evaluation of tumor sites by calculation of the apparent diffusion coefficient (ADC). Because of their high cellularity and high nucleus-to-cytoplasm ratio, lymphomatous lesions have low ADC values and appear hypointense on ADC maps. As a result, whole-body DW MR imaging with ADC mapping has become a promising tool for lymphoma staging and treatment response assessment. The authors review their 4 years of experience with 1.5-T and 3-T whole-body DW MR imaging used with (18)F-FDG PET/computed tomography at baseline, interim, and end of treatment in patients with Hodgkin lymphoma and diffuse large B-cell lymphoma and discuss the spectrum of imaging findings and potential pitfalls, limitations, and challenges associated with whole-body DW MR imaging in these patients.

Automated Liver Volumetry in Orthotopic Liver Transplantation Using Multiphase Acquisitions on MDCT

OBJECTIVE The aim of this study was to test a new automated hepatic volumetry technique by comparing the accuracies and postprocessing times of manual and automated liver volume segmentation methods in a patient population undergoing orthotopic liver transplantation so that liver volume could be determined on pathology as the standard of reference. CONCLUSION Both manual and automated multiphase MDCT-based volume measurements were strongly correlated to liver volume (Pearson correlation coefficient, r = 0.87 [p < 0.0001] and 0.90 [p < 0.0001], respectively). Automated multiphase segmentation was significantly more rapid than manual segmentation (mean time, 16 ± 5 [SD] and 86 ± 3 seconds, respectively; p = 0.01). Overall, automated liver volumetry based on multiphase CT acquisitions is feasible and more rapid than manual segmentation.

Liver resection for colorectal liver metastases with peri-operative chemotherapy: oncological results of R1 resections

BACKGROUND Retrospective analysis of outcomes of R0 (negative margin) versus R1 (positive margin) liver resections for colorectal metastases (CLM) in the context of peri-operative chemotherapy. METHODS All CLM resections between 2000 and 2006 were reviewed. Exclusion criteria included: macroscopically incomplete (R2) resections, the use of local treatment modalities, the presence of extra-hepatic disease and no peri-operative chemotherapy. R0/R1 status was based on pathological examination. RESULTS Of 86 eligible patients, 63 (73%) had R0 and 23 (27%) had R1 resections. The two groups were comparable for the number, size of metastases and type of hepatectomy. The R1 group had more bilobar CLM (52% versus 24%, P = 0.018). The median follow-up was 3.1 years. Five-year overall and disease-free survival were 54% and 21% for the R0 group and 49% and 22% for the R1 group (P = 0.55 and P = 0.39, respectively). An intra-hepatic recurrence was more frequent in the R1 group (52% versus 27%, P = 0.02) and occurred more frequently at the surgical margin (22% versus 3%, P = 0.01). DISCUSSION R1 resections were associated with a higher risk of intra-hepatic and surgical margin recurrence but did not negatively impact survival suggesting that in the era of efficient chemotherapy, the risk of an R1 resection should not be considered as a contraindication to surgery.

Differentiation of focal nodular hyperplasia from hepatocellular adenoma: Role of the quantitative analysis of gadobenate dimeglumine-enhanced hepatobiliary phase MRI.

To determine the value of quantitative analysis of the hepatobiliary phase (HBP) in gadobenate dimeglumine (Gd‐BOPTA)‐enhanced magnetic resonance imaging (MRI) to differentiate focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA).

Liver magnetic resonance diffusion weighted imaging: 2011 update.

Diffusion-Weighted-Imaging (DWI) assesses proton motion on a cellular scale. Owing to recent instrumentation developments, diffusion sequences are now routinely used for liver imaging. This review will go through the physical principles that underlie this technique, and then highlight up-to-date liver applications including quantification of liver fibrosis, focal lesions detection and characterization, and therapy response monitoring.

Invasive lobular carcinoma of the breast: MRI pathological correlation following bilateral total mastectomy.

Background Invasive lobular carcinoma (ILC) is more often multifocal and bilateral than invasive ductal carcinoma. MRI is usually recommended for detection of all ILC sites. The performance of known diagnostic breast MRI criteria for ILC characterization has not been evaluated to date using bilateral mastectomy specimens as gold standard. Purpose To determine the value of BI-RADS 2006 MRI criteria for ILC detection and characterization, using pathological examination of bilateral mastectomy specimens as the reference standard. Material and Methods Between 2004 and 2007, we retrospectively included all patients with pathologically documented ILC referred to our institution for bilateral mastectomy and preoperative bilateral breast MRI. The location, diameter, and characteristics (BI-RADS) of all lesions were compared with pathological findings. The sensitivity and positive predictive value of bilateral breast MRI for the diagnosis of ILC were calculated. Association of MRI BI-RADS categorical variables and characterization of ILC were assessed (Fisher exact test). Results Among 360 patients treated for ILC in 2004–2007, 15 patients qualified for this study. Thirty-one ILC foci were found on pathological examination (30 ipsilateral and 1 contralateral tumor; mean diameter 23 mm; range 2–60 mm) and all were identified on MRI, with 90% of masses and 10% non-mass-like enhancements; MRI features significantly associated with ILC included absence of smooth margins (P = 0.02) and rim-shaped enhancement (P = 0.039). Enhancement kinetics of the 31 foci were evenly distributed among wash-out, plateau, and persistent profiles. Eleven additional lesions were seen on MRI, mainly corresponding to fibrocystic disease; 91% presented as masses and 9% had a wash-out profile. Conclusion Based on the 2006 BI-RADS criteria, breast MRI shows a high sensitivity for ILC detection, at the expense of a 26% false-positive rate, suggesting that a pathological proof by US- or MR-guided biopsy is required in case of suspicious MRI images in this context.

Évaluation des critères diagnostiques non invasifs du carcinome hépatocellulaire sur IRM pré-greffe hépatique (2010) : corrélations IRM – anatomopathologiques sur explants hépatiques

PURPOSE To validate the 2010 diagnostic criteria from the American Association for the Study of Liver Diseases (AASLD) for hepatocellular carcinoma (HCC) on MRI using the surgical liver specimen as a gold standard. PATIENTS AND METHODS A total of 21 liver transplant recipients were retrospectively included. Each underwent surgery because of HCC between January 2007 and January 2008. Pre-transplant MRI was performed on a 1.5 Tesla MR unit. The T1W and T2W signal and kinetic contrast enhancement were correlated for each lesion with the surgical specimen. Lesion diameters between MRI and specimen were compared (Spearman). A multivariate model was created (R statistics software package) to predict the presence and grade of tumor differentiation (WHO, Edmonson Steiner). RESULTS A total of 71 nodules were detected at histology, including 54 HCC (mean size: 25.3mm) compared to 68 on MRI. There was moderate agreement (r=0.58, P<0.001) between the maximum lesion diameters measured on MRI and at histology. Wash-out on MRI provided an accuracy of 75 % for the detection of HCC (sensitivity=75 %, specificity=76 %). Adding T2W hyperintensity to the AASLD criteria increased the sensitivity of MRI from 70.3 % to 77.7 % for the diagnosis of HCC and from 67.6 % to 79 % for nodules less than 20mm in diameter, without affecting specificity. On multivariate analysis, wash out as a single variable was significantly associated with a diagnosis of HCC (P<0.01, odds ratio 12.0, CI 95 % [2.6-55.5]). T1W hyperintensity (P=0.04, odds ratio 5.4) and loss of signal on opposed-phase images (P=0.02, odds ratio 9.2) were predictive of good differentiation. CONCLUSION On MRI, the AASLD criteria or presence of wash out within a liver nodule in patients with underlying chronic hepatocellular disease are suggestive of tumoral transformation. The addition of T2W hyperintensity to the AASLD criteria increases the detection of HCC, especially nodules smaller than 20mm.

Recurring multicystic inflammatory pseudotumor of the liver: a case report.

Inflammatory pseudotumor (IPT) of the liver is a rare benign lesion for which imaging diagnosis remains a challenge. We report the case of a 39-year-old Algerian woman, who presented epigastric pains combined with fever and jaundice. Ultrasound, CT scan and MRI showed the presence of a 10 cm-long multi-septated cystic mass of the left lobe, with peripheral enhancement. A left-hepatectomy was performed and histopathology revealed an IPT of the liver. During the 4 following years, the patient had three other recurrences of liver IPT at various locations distinct from the original, revealed by the same clinical symptoms. During these relapses, the lesions did regress thanks to a medical treatment. This observation underlines the difficulty of the diagnosis and treatment of liver IPT.

Quantitative correlation between uptake of Gd-BOPTA on hepatobiliary phase and tumor molecular features in patients with benign hepatocellular lesions

PurposeThe purpose of our study was to correlate the quantitative analysis of benign hepatocellular tumor uptake on delayed hepatobiliary phase (HBP) imaging with the quantitative level of OATP expression.MethodsThis single-center retrospective study, which took place between September 2009 and March 2015, included 20 consecutive patients with a proven pathologic and immunohistochemical (IHC) diagnosis of FNH or HCA, including quantification of the OATP expression. The patients underwent Gd-BOPTA-enhancement MRI, including an HBP. The analysis of HBP uptake was performed using the liver-to-lesion contrast enhancement ratio (LLCER). Mean LLCER and OATP expressions were compared between FNH and HCA, and the expression of OATP was correlated with the LLCER value.ResultsOf the 23 benign hepatocellular tumors, 9 (39%) were FNH and 14 (61%) were HCA, including 6 inflammatory, 2 HNF1a inactivated, 3 β-catenin-mutated and 3 unclassified HCAs. On HBP, 100% of the FNH appeared hyper- or isointense, and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46.67 ± 26.58%) was significantly higher than that of HCA (22.14 ± 30.74%) (p = 0.0273), and the mean LLCER of FNH (10.66 ± 7.403%) was significantly higher than that of HCA (-13.5 ± 12.25%) (p < 0.0001). The mean LLCER of β-catenin-mutated HCA was significantly higher than that of other HCAs (p = 0.011). Significant correlation was found between the OATP expression and LLCER values (r = 0.661; p = 0.001).ConclusionIn benign hepatocellular tumors, the quantitative analysis of hepatobiliary contrast agent uptake on HBP is correlated with the level of OATP expression and could be used as an imaging biomarker of the molecular background of HCA and FNH.Key Points• Gd-BOPTA uptake on HBP correlates with the OATP level in benign hepatocellular tumors• FNH and β-catenin-mutated HCA showed an increased lesion-to-liver contrast enhancement ratio (LLCER)• Increased LLCER may be explained by activation of the Wnt β-catenin pathway