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  • Journal Highlights

    The following are highlights from the current issues of RSNA’s two peer-reviewed journals.

    January 1, 2016

    Pitfalls in Liver Imaging

    The liver is a tricky organ for radiologists. The external structure (lobes separated by the falciform ligament) does not reflect the internal structure, which has been clearly described by the anatomist Charles Couinaud.

    In a review article in the January issue of Radiology (RSNA.org/Radiology), Valerie Vilgrain, M.D., Ph.D., Matthieu Lagadec, M.D., and Maxime Ronot, M.D., Ph.D., of Université Paris Diderot and Hôpital Beaujon in Paris, discuss the major traps in image interpretation and give diagnostic clues to confidently interpret CT or MRI.

    Cirrhosis is the most common chronic liver disease, but certain other liver diseases may have a pseudocirrhotic appearance on imaging and require different patient management. The differentiation of true liver tumors from pseudotumors can be challenging.

    Essentials from the review include:

    • The majority of the noncirrhotic liver diseases, which mimic cirrhosis are of vascular or biliary origin.
    • Careful analysis of the large intra- and extrahepatic vessels is helpful to assess whether a large tumor originates from within or outside the liver.
    • The most common pseudolesions in segment 4 are related to focal fatty sparing or focal steatosis.

    “Most of these pitfalls can be avoided by the careful analysis of all imaging findings in relation to their fit with the clinical background of the patient,” the authors write.

    Molecular Imaging of Prostate Cancer

    In the management of prostate cancer, the methods currently applied for risk stratification, treatment selection and response prediction, as well as estimation of prognosis, are considered suboptimal. Molecular imaging of prostate cancer is a rapidly emerging field that aims to provide noninvasive insights into tumor biology and diversity on a whole-body scale.

    In an article in the January-February issue of RadioGraphics (RSNA.org/RadioGraphics), Andreas G. Wibmer, M.D., of Memorial Sloan Kettering Cancer Center, and colleagues provide an overview of the molecular imaging methods that are presently used or are undergoing clinical evaluation, including imaging of cell metabolism, hormone receptors and membrane proteins. They examine the advantages and disadvantages of each imaging strategy, its diagnostic value and its appropriate use.

    Key points include:

    • Radiolabeled metabolites are not specific to prostate cancer, and tracer accumulation may be observed at other sites of increased cell metabolism, including areas of inflammatory change, benign tumors and nonprostatic malignancies.
    • The binding of 18F-fluorodihydrotestosterone (FDHT) to the androgen receptor is drastically reduced by physiologic testosterone levels and the administration of antiandrogenic drugs. Thus, it is crucial to consider the patient’s current antiandrogenic medication when interpreting FDHT PET examinations.
    • The availability of both diagnostic and therapeutic versions of the same tracer allows implementation of a “theranostic” approach, in which an imaging probe can reliably predict the in vivo binding of its therapeutic “sister” agent and can also allow patient-tailored dosage calculations.
    • Despite its name, prostate-specific membrane antigen (PSMA) is not perfectly specific for prostate cells or prostate cancer, and possible pitfalls should be kept in mind in the interpretation of PSMA-based imaging studies.
    • Bone-seeking tracers will accumulate in the bone matrix but not in cancer cells, thus reflecting the osteoblastic response to the cancer rather than reflecting the tumor itself.

    “Selection of the imaging strategy most appropriate for the clinical situation, as well as knowledge about the biologic mechanisms underlying each imaging approach and the pharmacologic properties of the individual tracers, will help realize the full potential of tracers and avoid pitfalls. Also, there is an urgent need to develop standardized methodology for evaluating new and existing tracers that are relevant to prostate cancer imaging, to allow comparison of the results reported with different compounds,” the authors write.

    This article is accompanied by an Invited Commentary by Peter L. Choyke, M.D., from the Molecular Imaging Program at the National Cancer Institute.

    This article meets the criteria for AMA PRA Category 1 Credit™. SA-CME is available online only.

    Radiology Podcasts

    Listen to Radiology Editor Herbert Y. Kressel, M.D., deputy editors and authors discuss the following articles in the November issue of Radiology at RSNA.org/Radiology-Podcasts.

    • “Influence of Cardiac MR Imaging on DNA Double-Strand Breaks in Human Blood Lymphocytes,” Michael Brand, M.D., and colleague.
    • “Focal Nodular Hyperplasia and Hepatocellular Adenoma: Accuracy of Gadoxetic Acid–enhanced MR Imaging—A Systematic Review,” Matthew D. F. McInnes, M.D., and colleagues.
    • “CT Screening for Lung Cancer: Nonsolid Nodules in Baseline and Annual Repeat Rounds,” David F. Yankelevitz, M.D., and colleagues.

    Latest Radiology Select Volume 7 Spotlights Imaging the Liver

    Radiology Select vol 7In Volume 7 of Radiology Select, guest editors Valérie Vilgrain, M.D., and Maxime Ronot, M.D., have curated a collection of 31 Radiology articles that cover the most important advances in liver imaging.

    Subject areas include:

    • Diagnostic imaging with US, CT, and MRI
    • Disease detection and characterization with diffusion MRI
    • Quantitative imaging techniques
    • Liver-specific contrast agents
    • Advances in treatment of liver diseases

    The Online Educational Edition includes 13 tests with an opportunity to earn 13 SA-CME credits. This enduring material can be applied toward the ABR self-assessment requirement.

    Access all volumes of Radiology Select at RSNA.org/RadiologySelect.

    MR image in a 39-year-old woman with morphologic changes of the liver secondary to Budd-Chiari syndrome
    MR image in a 39-year-old woman with morphologic changes of the liver secondary to Budd-Chiari syndrome. Fat-suppressed fast SE T2-weighted MR images (2500–8000/90; flip angle, 90°; section thickness, 4 mm) show atrophy of the right and left liver lobe and hypertrophy of the caudate lobe. Hepatic veins are not patent and large hepatic venous collaterals (arrow) drain into the IVC. Splenomegaly and ascites are seen. (Radiology 2016;278;1:34-51) ©RSNA 2016 All rights reserved. Printed with permission.

    Newly diagnosed prostate cancer
    Newly diagnosed prostate cancer (Gleason score, 4 + 4 = 8; PSA level, 30 ng/mL) found at biopsy in a 64-year-old man who was referred for cancer staging. Carbon 11–labeled acetate PET/CT image shows a suspicious lesion (arrow) in the right prostatic peripheral zone. Note the physiologic uptake of 11C-acetate in the skeletal muscle. (RadioGraphics 2016;36;InPress) ©RSNA 2016 All rights reserved. Printed with permission.