Review article liver metastases

Liver metastases are a very common site of distant metastases. Detection and accurate characterization of liver metastases is of importance to guide therapy. A variety of imaging modalities such as US (including contrast agents), MDCT, MRI with liver –specific contrast agents and PET/CT are available for this purpose. This review presents imaging techniques and summarizes the current knowledge, how the different imaging modalities should be used

Morphologic and Molecular Features of Hepatocellular Adenoma with Gadoxetic Acid-enhanced MR Imaging

Purpose To evaluate the diagnostic performance of imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging to differentiate among hepatocellular adenoma (HCA) subtypes by using the histopathologic results of the new immunophenotype and genotype classification and to correlate the enhancement pattern on the hepatobiliary phase (HBP) with the degrees of expression of organic anion transporting polypeptide (OATP1B1/3), multidrug resistance-associated protein 2 (MRP) (MRP2), and MRP 3 (MRP3) transporters. Materials and Methods This retrospective study was approved by the institutional review board, and the requirement for informed consent waived. MR imaging findings of 29 patients with 43 HCAs were assessed by two radiologists independently then compared with the histopathologic analysis as the standard of reference. Receiver operating characteristic curves and Spearman rank correlation coefficient were used to test the diagnostic performance of gadoxetic acid-enhanced MR imaging features, which included the retention or washout at HBP and degree of transporter expression. Interreader agreement was assessed by using the κ statistic with 95% confidence interval. Results The area under the curve for the diagnosis of inflammatory HCA was 0.79 (95% confidence interval: 0.64, 0.90); for the steatotic type, it was 0.90 (95% confidence interval: 0.77, 0.97); and for the β-catenin type, it was 0.87 (95% confidence interval: 0.74, 0.95). There were no imaging features that showed a significant statistical correlation for the diagnosis of unclassified HCAs. On immunohistochemical staining, OATP1B1/3 expression was the main determinant for the retention, whereas MRP3 was the key determinant for washout of gadoxetic acid at HBP (P < .001). MRP2 appeared to have no role. Conclusion Gadoxetic acid-enhanced MR imaging features may suggest the subtype of HCA. The degree of OATP1B1/3 and MRP3 expression correlated statistically with gadoxetic acid retention and washout, respectively, in the HBP. (©) RSNA, 2015 Online supplemental material is available for this article

MRI texture analysis of subchondral bone at the tibial plateau

OBJECTIVES: To determine the feasibility of MRI texture analysis as a method of quantifying subchondral bone architecture in knee osteoarthritis (OA).   METHODS: Asymptomatic subjects aged 20-30 (group 1, n = 10), symptomatic patients aged 40-50 (group 2, n = 10) and patients scheduled for knee replacement aged 55-85 (group 3, n = 10) underwent high spatial resolution T1-weighted coronal 3T knee MRI. Regions of interest were created in the medial (MT) and lateral (LT) tibial subchondral bone from which 20 texture parameters were calculated. T2 mapping of the tibial cartilage was performed in groups 1 and 2. Mean parameter values were compared between groups using ANOVA. Linear discriminant analysis (LDA) was used to evaluate the ability of texture analysis to classify subjects correctly.   RESULTS: Significant differences in 18/20 and 12/20 subchondral bone texture parameters were demonstrated between groups at the MT and LT respectively. There was no significant difference in mean MT or LT cartilage T2 values between group 1 and group 2. LDA demonstrated subject classification accuracy of 97 % (95 % CI 91-100 %).   CONCLUSION: MRI texture analysis of tibial subchondral bone may allow detection of alteration in subchondral bone architecture in OA. This has potential applications in understanding OA pathogenesis and assessing response to treatment.   KEY POINTS: • Improved techniques to monitor OA disease progression and treatment response are desirable • Subchondral bone (SB) may play significant role in the development of OA • MRI texture analysis is a method of quantifying changes in SB architecture • Pilot study showed that this technique is feasible and reliable • Significant differences in SB texture were demonstrated between individuals with/without OA

Zufallsbefunde von Leber, Gallensystem, Pankreas und Milz bei asymptomatischen Patienten : Bewertung und Managementempfehlung

Klinisches Problem Die vermehrte Verwendung hoch entwickelter bildgebender Verfahren wie Multidetektorcomputertomographie und Magnetresonanztomographie hat zu einer beträchtlichen Zunahme asymptomatischer und unerwarteter Befunde geführt. Radiologische Standardverfahren Besonders betroffen sind abdominelle CT-Untersuchungen mit einer Vielzahl inzidenteller Befunde. Dieses wertvolle Diagnoseverfahren birgt auch die Gefahr aufwendiger und auch kostenintensiver Folgeuntersuchungen mit z. T. invasiven Verfahren. Bewertung Vor diesem Hintergrund stellt sich für den Radiologen immer häufiger die schwierige Aufgabe, diese Läsionen korrekt einzuschätzen, über die Notwendigkeit einer weiteren Abklärung zu entscheiden und den Patienten umfassend über die klinische Relevanz zu informieren. Empfehlung für die Praxis Das Ziel dieses Artikels ist es, die am häufigsten vorkommenden abdominellen Zufallsbefunde zu beschreiben sowie Hilfestellung bei ihrer Interpretation und Differenzialdiagnose mit Empfehlungen für das weitere Management zu geben.Clinical issue The increased use of highly developed imaging procedures, such as multidetector-row computed tomography and magnetic resonance imaging has led to a substantial increase of asymptomatic and unexpected findings. Standard radiological methods Abdominal CT investigations are particularly affected with a large number of incidental findings. This valuable diagnostic procedure also entails the risk of complex and cost-intensive subsequent investigations with partly invasive procedures. Achievements For this reason radiologists are more often confronted with the difficult task of correctly assessing these lesions, to decide on the need for additional investigations and to inform the patient in detail about the clinical relevance. Practical recommendations The aims of this article are to describe the most common abdominal incidentalomas, to assist with the interpretation and differential diagnosis and to give recommendations for further management.(VLID)353372

Der Radiologe / Zufallsbefunde von Niere, Nebenniere, Adnexen, Gastrointestinaltrakt, Mesenterium und Lymphknoten : Bewertung und Managementempfehlung

Klinisches Problem Neben den parenchymatösen Oberbauchorganen hat der zunehmende Einsatz von Schnittbildverfahren zu einer vermehrten Anzahl von Zufallsbefunden der Nieren, Nebennieren, Adnexe, des Gastrointestinaltrakts, Mesenteriums und der intraabdominellen Lymphknoten geführt. Radiologische Standardverfahren Abdominelle CT-Untersuchungen zeigen häufig unerwartete Befunde ohne korrelierende Symptomatik. Die steigende klinische Relevanz ist einerseits auf die Zunahme inzidenteller Pathologien und andererseits auf ein wachsendes Bewusstsein ethischer und sozioökonomischer Faktoren zurückzuführen. Bewertung Bei der radiologischen Interpretation sind neben morphologischen Kriterien sowohl die Einbeziehung der individuellen Risikofaktoren des Patienten als auch der klinische Gesamtkontext von großer Bedeutung. Empfehlung für die Praxis Das Ziel dieses Artikels ist eine Beschreibung und Bewertung der in der Computertomographie detektierten genannten Zufallsbefunde sowie weiterer Managementempfehlungen.Clinical issue Besides the upper abdominal parenchymal organs, the increasing application of cross-sectional imaging has also led to a rising number of incidental findings in the kidneys, adrenal glands, adnexa uteri, the gastrointestinal tract, mesentery and abdominal lymph nodes. Standard radiological methods Abdominal computed tomography investigations often show unexpected findings without any correlating symptoms. The growing clinical relevance is due to the large number of incidental findings as well as an increasing awareness of ethical and socioeconomic factors. Achievements When interpreting radiological findings not only morphological criteria but also individual risk factors of the patient and the clinical context are of great importance. Practical recommendations The aims of this article are the description and evaluation of frequent incidental findings detected by computed tomography and to provide information about management recommendations.(VLID)353373

Moderne Diagnostik zystischer Leberl\ue4sionen und H\ue4mangiome

Clinical issue: Cystic liver lesions incorporate a broad heterogeneous group of mostly benign but also malignant abnormalities. The radiological aim is the non-invasive diagnosis with the use of different imaging modalities to determine the type of lesion.Standard radiological methods: The common generally asymptomatic incidental findings of cystic lesions on ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) must be classified on the basis of specific imaging features. Such a differentiation is essential because the clinical consequences and the appropriate therapy can vary depending on the underlying pathology. Due to the morphological overlap of many cystic lesions, conventional radiological methods are often insufficient.Methodical innovations: The huge advances in cross-sectional imaging (multidetector CT, MRI with special sequences and different contrast agents and MR cholangiopancreatography) in combination with the clinical history usually enable a non-invasive diagnosis. Pathognomonic morphological and hemodynamic lesion features, as well as a knowledge of the pathomechanisms, help to differentiate this broad spectrum of entities.Achievements: In this article the different entities of cystic liver lesions, together with the appropriate diagnostic method for detection and distinction and including their strengths and limitations, are demonstrated.Practical recommendations: A well-founded knowledge about the development of various cystic liver lesions and the suitable choice of imaging method facilitate a non-invasive diagnosis