[Incidental and "leave me alone" findings in the GI tract-part 1 : Intestinal lumen and intestinal wall]. / Inzidentelle und Leave-me-alone-Befunde des GI-Trakts ­ Teil 1 : Darmlumen und Darmwand.

CLINICAL PROBLEM: Due to the widespread use of computed tomography (CT) and magnetic resonance imaging (MRI) asymptomatic incidental findings of the gastrointestinal tract (GI) are increasingly being recognized. Incidental findings are frequently not part of the primary inquiry from referring physicians but it is obligatory to make a diagnosis and to stipulate the need for further clarification. RADIOLOGICAL STANDARD PROCEDURES: A multitude of incidental findings in the intestinal lumen, in the intestinal wall and in the adjacent mesenterium or subperitoneal space are shown in CT and MRI. METHODOLOGICAL INNOVATIONS AND ASSESSMENT: The first part of the two-part overview addresses the intestinal incidental findings in the lumen, such as coproliths, invaginations, mucoceles and chronic dilatations. In the intestinal wall, thickenings of neoplastic and nonneoplastic origins are discussed. Many of the findings can be classified as benign and as "leave me alone lesions" do not necessitate any further clarification but in contrast others need a definitive clarification. The most important incidental findings in the GI tract are systematically classified, illustrated and evaluated with respect to the clinical relevance, depending on the localization (e.g. stomach, small and large intestines).

[Incidental and "leave me alone" findings of the GI tract-part 2 : Intestinal wall and mesentery]. / Inzidentelle und Leave-me-alone-Befunde des GI-Trakts ­ Teil 2 : Darmwand und Mesenterium.

Due to the widespread use of computed tomography (CT) and magnetic resonance imaging (MRI) asymptomatic incidental findings of the gastrointestinal (GI) tract are increasingly being recognized. Incidental findings are frequently not part of the primary inquiry from referring physicians but it is obligatory to make a diagnosis and to stipulate the need for further clarification. A multitude of incidental findings in the intestinal lumen, in the intestinal wall and in the adjacent mesentery or subperitoneal space are shown in CT and MRI of the GI tract. The last part of the two-part review addresses the gastrointestinal incidental findings in the intestinal wall and the adjacent sections. Extramural incidental findings occur as mesenteric inflammation, tumors and cysts. Many of the findings can be classified as benign and as "leave me alone lesions" do not necessitate any further clarification but in contrast others need a definitive clarification. The most important incidental findings in the GI tract are systematically classified, illustrated and evaluated with respect to the clinical relevance, depending on the localization (e.g. stomach, small and large intestines).

[Incidental and leave me alone findings of abdominal organs-part 2 : Spleen, kidneys and adrenal glands and efferent urinary tracts]. / Inzidentelle und Leave-me-alone-Befunde der abdominellen Organe ­ Teil 2 : Milz, Niere und Nebennieren sowie ableitende Harnwege.

For masses of the spleen, which are mostly benign, accessory spleens, cysts and hemangiomas should be radiologically described; however, if confirmed further follow-up control is unnecessary. In the case of disseminated small masses, chronic inflammation and granulomatous diseases, such as tuberculosis and sarcoidosis should be considered in the differential diagnostics. Solid masses in the kidneys should always be further clarified, with the exception of a fat-rich angiomyolipoma. For cystic masses of the kidneys, the modified Bosniak classification for computed tomography or magnetic resonance imaging should be used. Masses of the adrenal glands greater than 10mm in size should be clarified further as well as those where fat is not detected, independent of the size and evidence of malignancy.

[Incidental and "leave me alone" findings of abdominal organs-part 1 : Liver, gall ducts and pancreas]. / Inzidentelle und Leave-me-alone-Befunde der abdominellen Organe ­ Teil 1 : Leber, Gallenwege und Pankreas.

Incidentalomas of the parenchymal organs of the abdomen, i.e. radiological findings in these organs that are not the primary focus of the clinical question, are frequent in this region of the body. In particular, findings presumed to be unimportant, such as cystic masses in the liver, the bile duct system or the pancreas, initially appear to be irrelevant in the diagnosis. For the liver we define the mostly clearly diagnosable simple cysts and hemangiomas as leave me alone lesions. Otherwise, we recommend a classification of incidentalomas into the three major categories (<0.5 cm, 0.5-1.5 cm and >1.5 cm) as well as an assessment with respect to clearly benign and suspect imaging characteristics in the context of a classification of patients into three different risk groups.

[Rational staging and follow-up of colorectal cancer : Do guidelines provide further help?] / Rationales Staging und Follow-up beim kolorektalen Karzinom : Helfen Leitlinien weiter?

CLINICAL/METHODICAL ISSUE: Colorectal cancer is one of the most common malignant tumors. Preoperative imaging is crucial in rectal cancer as patients can only receive optimal treatment when accurate staging is performed. The N­staging is often difficult with the available options and must be called into question as a staging parameter. STANDARD RADIOLOGICAL METHODS: Endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) are particularly suitable for local staging. Multiparametric MRI with diffusion imaging is indispensable for tumor follow-up. METHODICAL INNOVATIONS: The assessment of infiltration of the mesorectal fascia is best accomplished using high-resolution MRI. In addition, extramural vascular infiltration (EMVI) has become established as another important prognostic factor. After neoadjuvant therapy and restaging of locally advanced rectal cancer, the identification and validation of prognostically relevant image parameters are prioritized. Multiparametric MRI of the rectum including diffusion imaging as well as the application of radiological and pathological scores (MR-TRG) are becoming increasingly more important in this context. ASSESSMENT: For the radiologist it is important to become familiar with indicators of the resectability of rectal cancer and to be able to reliably read prognostically relevant imaging parameters in the tumor follow-up. PRACTICAL RECOMMENDATIONS: For the practical application, the establishment of a fixed MRI protocol is essential. In addition to a guideline-compliant TNM classification, the radiologist must provide the clinician with information on infiltration of the mesorectal fascia and extramural vascular infiltration. The MR-TRGs are becoming increasingly more important in tumor follow-up.

[Neuroendocrine tumors of the abdomen]. / Neuroendokrine Tumoren des Abdomens.

CLINICAL/METHODICAL ISSUE: Gastroenteropancreatic neuroendocrine neoplasia (GEP-NEN) are a heterogeneous group of complex tumors, which is often difficult to classify due to heterogeneity and varying locations. STANDARD RADIOLOGICAL METHODS: Ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron-emission tomography computed tomography (PET/CT) are available for the localization of NEN as well as for the staging. METHODOLOGICAL INNOVATIONS: In particular, nuclear medical examination methods with somatostatin analogues are of great importance since radioactively labeled receptor ligands make tumors visible with high sensitivity. PERFORMANCE: CT and MRT have high detection rates for GEP-NEN and have been further improved by developments such as diffusion weighted imaging. The nuclear medical methods, however, are superior in detection, especially in gastrointestinal NEN ACHIEVEMENTS: It is important for the radiologist to become acquainted with the NEN as they can occur ubiquitously in the abdomen and should be identified as such. PRACTICAL RECOMMENDATIONS: Since GEP-NEN are predominantly hypervascularized, a biphasic examination technique is obligatory for contrast-enhanced cross-sectional imaging. PET/CT with somatostatin analogs should be used for further diagnosis.

[Criteria for resectability of pancreatic cancer and postoperative imaging]. / Resektabilitätskriterien beim Pankreaskarzinom und postoperative Bildgebung.

By improving the techniques of pancreatic surgery, the mortality and morbidity for pancreatic carcinoma could be significantly reduced. For radiologists a profound knowledge of the surgical techniques is of decisive importance. Based on this knowledge postoperative complications can be reliably uncovered and local recurrences can be detected at an early stage. The complications resulting from pancreatic surgery can be severe and often necessitate a radiological intervention. As pancreatic cancer itself is a severe disease with a poor 5­year survival, which can only be improved by an R0 resection, it is crucial to identify using imaging those patients who are primarily operable or who can potentially achieve an operable condition through neoadjuvant chemotherapy (borderline) and inoperable patients to avoid postoperative complications which would additionally weaken them and result in unnecessary delays in initiating palliative therapy. Thus, familiarity with the clinical criteria of resectability and also inoperability in pancreatic cancer nowadays represents an essential basic knowledge for every oncological radiologist.

[Pancreatitis: An update]. / Pankreatitis : Ein Update.

BACKGROUND: Acute and chronic pancreatitis are becoming increasingly more severe diseases in the western world with far-reaching consequences for the individual patient as well as the socioeconomic situation. This article gives an overview of the contribution of radiological imaging to the diagnostics and therapy of both forms of the disease. RESULTS: Acute pancreatitis can be subdivided into severe (20%) and mild manifestations. The diagnostics should be performed with computed tomography (CT) or magnetic resonance imaging (MRI) for assessing necrosis or potential infections only in severe forms of pancreatitis. In chronic pancreatitis transabdominal ultrasound should initially be adequate for assessment of the pancreas. For the differential diagnosis between pancreatic carcinoma and chronic pancreatitis, MRI with magnetic resonance cholangiopancreatography (MRCP) followed by an endoscopic ultrasound-guided fine needle aspiration is the method of choice. CONCLUSION: For the primary diagnosis for acute and chronic pancreatitis ultrasound examination is the modality of first choice followed by radiological CT and MRI with MRCP examinations.

3D detection of colonic polyps by CT colonography: accuracy, pitfalls, and solutions by adjunct 2D workup.

Computed tomography colonography (CTC) enables evaluation of the colon with minimal invasiveness. In spite of advances in multidetector CT (MDCT) technology and advanced software features, including electronic bowel cleansing (digital removal and tagging of fluid and debris), a number of potential pitfalls in the evaluation of the 3D volumetric dataset persist. The purpose of this article is to illustrate the strengths and potential pitfalls in the detection of colorectal polyps using CTC via a primary three-dimensional (3D) approach for evaluation.

Can the tibial slope be measured on lateral knee radiographs?

PURPOSE: The posterior tibial slope influences both the natural knee stability as well as the stability and kinematics after total knee arthroplasty (TKA). Exact definition of the posterior tibial slope (PTS) requires lateral radiographs of the lower limb. Only lateral knee radiographs are routinely obtained after TKA, however. The purpose of the present study therefore was to analyse the relationship between PTS measurement results on short and expanded lateral knee radiographs. METHODS: The PTS was measured on 100 consecutive lateral radiographs of the lower limb using the mechanical and three diaphyseal axes with various distances below the tibial plateau. RESULTS: Significant differences between PTS results were found for all three diaphyseal axes, with the smallest differences and the strongest correlation for a diaphyseal axis at 16 and 20 cm below the tibial plateau. Using short distances below the tibial plateau (6 and 10 cm) resulted in an overestimation of the PTS of 3°, on average. CONCLUSION: The PTS measurements in long lateral knee radiographs are more accurate compared to short radiographs. On short lateral knee radiographs, only a estimation of the PTS can be carried out. LEVEL OF EVIDENCE: Diagnostic study, Level II.

[Autoimmune pancreatitis versus pancreatic cancer]. / Autoimmunpankreatitis versus Pankreaskarzinom.

CLINICAL ISSUE: Autoimmune pancreatitis (AIP) is classified as a distinct form of pancreatitis according to the guidelines. It is characterized by imaging morphologic and histologic features and is associated with extrapancreatic manifestations in type 1 IgG 4-associated disease. Symptoms and findings almost always improve with administration of steroids. Differentiation from pancreatic ductal adenocarcinoma is required, particularly in the presence of AIP with focal parenchymal involvement. STANDARD RADIOLOGIC PROCEDURES: If AIP is suspected, abdominal ultrasound and/or endosonography, computed tomography (CT), and preferably magnetic resonance imaging (MRI) are indicated. A distinction is made between parenchymal and ductal changes that specifically indicate the presence of AIP. METHODOLOGICAL INNOVATIONS AND EVALUATION: The diagnosis of autoimmune pancreatitis should be made based on the International Consensus Criteria (ICDC), in which the five main features (imaging, serology, histology, other organ involvement, response to steroid medication) are assessed. In type 1 AIP, typical imaging changes are sufficient to establish the diagnosis even with negative histology, whereas for type 2 AIP, histologic evidence is required. Imaging changes help in the differential diagnosis from pancreatic cancer. PRACTICAL RECOMMENDATIONS: The following article addresses and evaluates crucial imaging diagnostic CT and MRI criteria for correct classification of findings, description of results, and differentiation of autoimmune pancreatitis from pancreatic cancer.

[Perfusion computed tomography for diffuse liver diseases]. / Perfusions-CT bei diffusen Lebererkrankungen.

CLINICAL/METHODICAL ISSUE: Perfusion computed tomography (CT) has its main application in the clinical routine diagnosis of neuroradiological problems. STANDARD RADIOLOGICAL METHODS: Polyphase multi-detector spiral computed tomography is primarily used in liver diagnostics. METHODICAL INNOVATIONS: The use of perfusion CT is also possible for the diagnostics and differentiation of diffuse hepatic diseases. PERFORMANCE: The differentiation between cirrhosis and cirrhosis-like parenchymal changes is possible. It also helps to detect early stages of malignant tumors. ACHIEVEMENTS: However, there are some negative aspects, particularly that of radiation exposure. PRACTICAL RECOMMENDATIONS: This paper summarizes the technical basics and possible applications of perfusion CT in cases of diffuse liver disease and weighs up the advantages and disadvantages of the examinations.

[Diagnostic Imaging of pancreatic carcinoma-Update of the new guideline]. / Diagnostik beim Pankreaskarzinom ­ Update in der neuen Leitlinie.

The new German S3 guidelines on ductal pancreatic adenocarcinoma were published for the first time on the homepage of the Association of the Scientific Medical Societies in Germany (AWMF) in December 2021 as a new update and thus the second update (first update 2013) and contain a large number of innovations in terms of diagnostics and treatment. The guidelines were organized and led by the German Society for Digestive and Metabolic Diseases (DGVS). In this article we would like to present the central content and innovations related to the radiological diagnostics of ductal pancreatic adenocarcinoma. The most important innovations are the highest recommendation strength in favor of computed tomography (CT) when assessing tumor spread as well as the adaptation of the European guidelines for cystic tumors by magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) as the method of first choice. A further innovation is the implementation of a structured reporting of CT findings for describing the anatomical tumor resectability on the basis of the publication presented by the Abdominal Imaging Working Group and the Oncological Imaging Working Group of the German Radiological Society. There is no evidence for the implementation of radiological imaging in the field of aftercare or in the field of screening.

[Diagnostics of vascular diseases as a cause for acute abdomen]. / Diagnostik vaskulärer Erkrankungen als Ursache für das akute Abdomen.

Vascular pathologies are rare causes of an acute abdomen. If the cause is a vascular disease a rapid diagnosis is desired as vascular pathologies are associated with high mortality. A differentiation must be made between arterial and venous diseases. An occlusion of the superior mesenteric artery is the most common reason for acute mesenteric ischemia but intra-abdominal arterial bleeding is also of great importance. Venous pathologies include thrombotic occlusion of the portal vein, the mesenteric vein and the vena cava.Multi-detector computed tomography (MDCT) is predestined for the diagnostics of vascular diseases of the abdomen. Using multiphasic contrast protocols enables reliable imaging of the arterial and venous vessel tree and detection of disorders with high sensitivity and specificity. Although conventional angiography has been almost completely replaced by MDCT as a diagnostic tool, it is still of high importance for minimally invasive interventions, for example in the management of gastrointestinal bleeding.

Noninvasive MRI-Based Liver Iron Quantification: Methodic Approaches, Practical Applicability and Significance.

Due to the dependence of transverse relaxation times T2 and T2* on tissue iron content, MRI offers different options for the determination of iron concentration. These are the time-consuming spin-echo sequence as well as the gradient-echo sequence. For the latter, several data analysis approaches have been proposed, with different requirements for acquisition and post-processing: the mathematically challenging R2* analysis and the signal-intensity ratio method with its high demand on the signal homogeneity of MR images. Furthermore, special procedures currently under evaluation are presented as future prospects: quantitative susceptibility imaging, as a third approach for analyzing gradient echo data, and multi-contrast spin-echo using repeated refocusing pulses. MR theory, as far as needed for understanding the methods, is briefly depicted. Key points: • Description of underlying technology of different MRI-based procedures for liver iron quantification• Applicability of these methods in clinical practice• Validity of the methods, i. e. positive and negative predictive value, if available Citation Format: • Wunderlich AP, Cario H, Juchems MS et al. Noninvasive MRI-Based Liver Iron Quantification: Methodic Approaches, Practical Applicability and Significance. Fortschr Röntgenstr 2016; 188: 1031 - 1036.

MRI-Based Liver Iron Content Determination at 3T in Regularly Transfused Patients by Signal Intensity Ratio Using an Alternative Analysis Approach Based on R2* Theory.

OBJECTIVES: To evaluate the feasibility of addressing liver iron content (LIC) in regularly transfused patients by MR imaging at 3 T based on the signal intensity ratio (SIR). An innovative data analysis approach was developed for this purpose. METHODS: 47 consecutive examinations of regularly transfused patients were included. In all cases, we expected high LIC levels. Patients were scanned with MRI at 3 T with multi-echo gradient echo sequences (GRE) at four different flip angles between 20° and 90° with echo times (TE) ranging from 0.9 to 9.8 ms. Spin-echo protocols were acquired to determine the LIC with a reference MRI method working at 1.5 T. 3 T GRE data were analyzed using the liver-to-muscle SIR. Since the method known for 1.5 T was not expected to be applicable for analyzing 3 T data, theoretic dependence of the SIR on the LIC was derived from the equation describing R2* signal decay. Obtained SIR values were correlated to reference LIC to get a relation for calculating LIC from SIR quantities. LIC values and their uncertainties were determined from GRE data and correlated to LIC reference values. For two LIC thresholds, the diagnostic accuracy was determined. RESULTS: LIC was reliably determined from SIR in our patient cohort even for large LIC values. Median of LIC uncertainties was 10 %, and the diagnostic accuracy was 0.92 and 0.91, respectively. CONCLUSION: Determination of even high LIC, resulting in small SIR values, is feasible at 3 T using appropriate SIR analysis. KEY POINTS: • Determination of Liver Iron Concentration (LIC) based on GRE MRI at 3T is feasible even for high LIC levels using Signal Intensiy Ratios. • Relative uncertainty of LIC determined with 3T GRE MRI was below 13 % in most cases. • The patient-management relevant threshold (LIC = 80 µmol/g (4.5 mg/g)) yielded an accuracy of .92 in our cohort. • The proposed method is quick and simple, both in terms of data acquisition and analysis. Citation Format: • Wunderlich AP, Cario H, Bommer M et al. MRI-Based Liver Iron Content Determination at 3T in Regularly Transfused Patients by Signal Intensity Ratio Using an Alternative Analysis Approach Based on R2* Theory. Fortschr Röntgenstr 2016; 188: 846 - 852.

A Review of Scientific Topics and Literature in Abdominal Radiology in Germany--Part 2: Abdominal Parenchymal Organs.

UNLABELLED: The working group for abdominal and gastrointestinal diagnosis is a group of the German Radiological Society (DRG) focusing clinically and scientifically on the diagnosis and treatment of the gastrointestinal tract as well as the parenchymal abdominal organs. In this article we give an up-to-date literature review of scientific radiological topics especially covered by German radiologists. The working group experts cover the most recent relevant studies concerning liver-specific contrast media with an emphasis on a new classification system for liver adenomas. Additionally studies regarding selective internal radiotherapy (SIRT) are reviewed. For the pancreas the most important tumors are described followed by an introduction to the most recently introduced functional imaging techniques. The manuscript concludes with some remarks on recent studies and concerning chronic pancreatitis as well as autoimmune pancreatitis. KEY POINTS: • Different subtypes of liver adenomas with different therapeutic consequences can be differentiated by MRI • Most recently published studies focus on liver imaging with extracellular liver specific contrast media as well as diffusion weighted imaging. They consider this new method having a high diagnostic potential. • For pancreatic neoplasm diagnosis diffusion--as well as perfusion--imaging is considered as a highly promising method.

A Review of Scientific Topics and Literature in Abdominal Radiology in Germany - Part 1: Gastrointestinal Tract.

UNLABELLED: The working group for abdominal and gastrointestinal diagnosis is a group of the German Radiological Society (DRG) focusing clinically and scientifically on the diagnosis and treatment of the gastrointestinal tract with all parenchymatous abdominal organs. In addition to the clinical and scientific further development of abdominal radiology, the education of radiologists within this core discipline of radiology is one of the major aims. In this article we give an up-to-date literature review of scientific radiological topics especially covered by German radiologists. This manuscript focuses on the most recent literature on the diagnosis of the stomach, small bowel, colon and rectum. The review with a focus on the most recent studies published by German radiologists concludes with a synopsis of mesenterial bleeding and ischemia followed by a critical appraisal of the current literature on conventional abdominal radiography. KEY POINTS: Based on recent literature and guidelines there is a change of paradigms regarding the diagnosis of esophagus and gastric cancer towards CT, which is considered equally to endosonography. For small bowel imaging in Crohn's disease ultrasound as well as MRI with a new focus on DWI are the most important imaging modalities scientifically. For colonic diagnosis virtual colonoscopy has replaced the conventional radiological methods. For staging of rectal carcinoma as well as for therapeutic stratification a high resolution MRI of the pelvis is of paramount interest. Multislice CT is considered the most important modality to assess mesenteric ischemia or bleeding.

[Non-invasive, multi detector row (MDR) CT based computational fluid dynamics (CFD) analysis of hemodynamics in infrarenal abdominal aortic aneurysm (AAA) before and after endovascular repair]. / Blutflusssimulation mittels Computational-Fluid-Dynamics an aus CT-Daten rekonstruierten Aortenaneurysmata vor und nach Stent-Graft Implantation.

PURPOSE: Simulation, description and analysis of dynamic pressure in infrarenal abdominal aortic aneurysms (AAA) before and after endovascular repair. MATERIALS AND METHODS: During March 1996 and May 2001, 13 patients with AAA underwent endovascular treatment. The MDR-CT scans of these patients were used for the non-invasive analysis of the hemodynamics in the aorta with CFD software before and after endovascular repair. One pre-interventional and three post-interventional CT scans were analyzed for each patient. RESULTS: Compared to the pre-interventional simulation, endovascular treatment led to an average dynamic pressure decrease of 1057 Pa in 10 of 13 patients. During the subsequent course, the median of the dynamic pressure decreased in 8 of 13 patients. Vulnerable regions initially identified as high-pressure regions, like the docking area or the second stent limb, adapted to the pressure in the surrounding tissue in the course of time. CONCLUSION: CFD-based blood flow simulation offers the opportunity to analyze dynamic pressure in AAA before and after endovascular repair and allows a prognostic statement as to the possible homogenization of the pressure in abdominal stent-grafts.