[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.

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 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.

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.

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.

[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.

Liver iron content determined by MRI: spin-echo vs. gradient-echo.

PURPOSE: Liver iron content (LIC) measurement plays a central role in the management of patients with transfusional iron overload. Calculating the LIC with data obtained from standardized MRI sequences represents an attractive alternative diagnostic possibility. The purpose of this study was to compare the LIC measurement obtained with gradient-echo (GRE) sequences to the mean liver proton transverse relaxation (R2) acquired with SE sequences. MATERIALS AND METHODS: 68 patients with iron overload (median age: 24, range: 3-88) underwent 1.5 T MRI for liver iron content measurement. All patients received spin-echo (SE) and gradient-echo (GRE) sequences. RESULTS: The two MRI methods revealed different liver iron content results although a significant correlation was found (r=0.85, p<0.001). Values evaluated using GRE sequences (median: 260 µmol/g dry weight [d. w.], range: 6-732) were generally higher than those obtained by SE examinations (median: 161 µmol /g d. w., range: 5-830). CONCLUSION: In conclusion, our study revealed different results for both MRI measurements, which could lead to different decisions concerning the management of chelation therapy in individual patients.

[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.

[CT colonography: evaluation of two 3D algorithms in a screening population]. / CT-Kolografie: Vergleich zweier Visualisierungsalgorithmen an einem Screeningkollektiv.

PURPOSE: The purpose of this multicenter study was to compare a dissection display and an endoluminal display for CT colonography (CTC) by means of detection rates and evaluation time in a screening collective. MATERIALS AND METHODS: 4 blinded readers evaluated CTC datasets from 42 patients with 55 endoscopically confirmed polyps. The datasets were read in a randomized order using two different 3D visualization methods (endoluminal view vs. dissection display; EBW 2.0.1, Philips Medical Systems, Best/NL). Patients underwent cathartic cleansing as well as stool and fluid tagging. All readers except one were experienced in performing CTC. The per-lesion/per-patient sensitivity, per-patient specificity, and evaluation time were calculated. RESULTS: The overall per-lesion sensitivity using the dissection display (and endoluminal view) was 60% (53 %) for reader 1, 58% (60%) for reader 2, 67% (71%) for reader 3 and 55% (58%) for reader 4. The per-patient sensitivity using the dissection display (and endoluminal view) was 85% (85%) for reader 1, 80% (85%) for reader 2, 95% (90%) for reader 3 and 80% (80%) for reader 4. The per-patient specificity was 68% with dissection view (77% endoluminal view) for reader 1, 82% (82%) for reader 2, 59% (59%) for reader 3 and 82% (73%) for reader 4. The experienced readers were significantly faster using the perspective-filet view. CONCLUSION: Using a dissection display of CTC datasets does not result in superior detection rates for polyps if datasets are stool and fluid-tagged. 3 out of 4 readers evaluated the datasets significantly faster with the dissection display.

Value of MDCT in preoperative local staging of rectal cancer for predicting the necessity for neoadjuvant radiochemotherapy.

PURPOSE: Neoadjuvant therapy may reduce local rectal cancer recurrence after total mesorectum extirpation. This study was performed to assess whether multi-detector row CT (MDCT) is capable of reliably differentiating UICC I (surgery) from UICC II-IV (neoadjuvant therapy). MATERIALS AND METHODS: 29 patients underwent preoperative MDCT of the abdomen in a portal venous phase. Two blinded readers independently evaluated the datasets on a dedicated workstation using axial and coronal reformations. Local tumor extension (T), nodal status (N) and distant metastases (M) were evaluated and the UICC stage was determined. Findings were correlated with postoperative histology. RESULTS: Histologically, 9 patients were UICC I; 20 UICC > I (II: 7; III: 11; IV: 2). Reader 1 correctly identified 3 / 9 as UICC I, overstaged 6 / 9, and correctly staged 20 / 20 as UICC > I. Reader 2 correctly identified 4 / 9 as UICC I, overstaged 5 / 9, understaged 4 / 20 and correctly staged 16 / 20 as UICC > I (PPV UICC I 100 % [50 %] reader 1 [reader 2], NPV 77 % [76 %], accuracy 79 % [69 %]). Reasons for overstaging by reader 1 (reader 2) included false-positive lymph nodes (LN) in 5 (5), overgrading T 1 tumors as T 3 in 1(0), and T overgrading in 4 / 5 (2 / 5) patients with false-positive LN. CONCLUSION: MDCT failed to reliably identify UICC I in rectal cancer patients. Therefore, a strategy based solely on MDCT to identify patients who would benefit from neoadjuvant therapy does not seem appropriate.

[Current imaging for rectal cancer]. / Aktuelle Bildgebung beim Rektumkarzinom.

Rectal cancer is one of the most common causes of death from cancer. Accurate staging is necessary for optimal treatment. The tumor node metastasis (TNM) system is used to describe numerically the anatomical extent of cancer. Various diagnostic methods provide accurate staging. Endorectal ultrasound (EUS) and magnetic resonance tomography (MR) are most adequate for determining tumor stage. Moreover, MR is highly accurate in predicting the circumferential resection margin. Accurate node staging remains however difficult with both EUS and MR. Modern multidetector row CT is predestined for detecting distant metastases as it is a widespread, fast, and reproducible method.

Atypical bronchial thickening and ulceration: a rare radiological finding in Wegener's granulomatosis.

We report the case of a 55-year-old male patient who presented with non-specific pulmonary symptoms (cough, haemoptysis, fever up to 39 degrees C, night sweats and weight loss). After empirical antibiotic therapy prescribed by his primary care physician, the patient showed no improvement in symptoms. Laboratory findings were: elevated C-reactive protein and C-ANCA, leukocytosis and thrombocytosis, and anaemia. Chest radiography showed disseminated nodules bilaterally. On multidetector-row computed tomography (MDCT), the bronchial walls showed a significant thickening and extensive peribronchiolar consolidations. Bronchoscopy revealed diffuse erythema of the tracheobronchial mucosa with diffusely scattered white plaques. Histopathology described a multifocal ulcerative bronchitis with underlying chronic bronchitis. These findings in combination with the laboratory data lead to the diagnosis of Wegener's granulomatosis. Consequently, we started with an immunosuppressive therapy. Chest radiography after 10 days showed marked resolution of the infiltrates. Within 1 month, the patient became asymptomatic.

A retrospective evaluation of patient acceptance of computed tomography colonography ("virtual colonoscopy") in comparison with conventional colonoscopy in an average risk screening population.

PURPOSE: To evaluate patient acceptance of computed tomography (CT) colonography compared with conventional colonoscopy by means of a self-assessed questionnaire. MATERIAL AND METHODS: Four-hundred-and-one patients with valid address information from our patient collective were preselected. Patient acceptance was evaluated retrospectively using a self-assessed questionnaire. The patients underwent CT colonography in our institution using 4x or 16x multi-detector row (MDR) CT. Two-hundred-and-forty-six patients returned a completed questionnaire, 157 of these indicating that they had undergone both virtual and conventional colonoscopy. RESULTS: One-hundred-and-twenty (76.4%) of the 157 patients would undergo another CT colonography if necessary, while only 14 patients would not. One-hundred-and-sixteen (73.9%) patients favored the actual examination procedure of CT colonography (P<0.0001), while only 6.4% preferred the conventional method. Preparation prior to CT colonography was experienced as more convenient than preparation prior to conventional colonoscopy (52.2% versus 14%). CONCLUSION: CT colonography was preferred in terms of both preparation and the actual procedure itself.

[Radiological diagnosis of Klatskin's tumour]. / Radiologische Diagnostik von Klatskin-Tumoren.

Patients with Klatskin's tumour present clinically unspecific symptoms such as painless jaundice and cholangitic discomfort. The only curative treatment is R0 resection of the tumour. To allow stage-specific therapy, accurate tumour staging is indispensable, the first step of which is abdominal sonography. If there is a suspect finding, cross-sectional imaging techniques like MRI or MDR-CT are used to clarify or stage the lesion, respectively. To estimate resectability, MRI together with MRC and MRI angiography are superior to MDR-CT. Biopsy using ERC is required before starting any specific treatment. If therapeutically relevant peritoneal carcinosis is clinically suspected although not radiologically confirmed, PET should also be performed. The value of PET/CT has to be evaluated in further studies. For optimal treatment, close cooperation between clinicians and radiologists is necessary.