Measurement of kidney perfusion by magnetic resonance imaging: comparison of MRI with arterial spin labeling to para-aminohippuric acid plasma clearance in male subjects with metabolic syndrome.

BACKGROUND: Magnetic resonance imaging with arterial spin labeling (MRI-ASL) is a non-invasive approach to measure organ perfusion. We aimed to examine whether MRI-ASL kidney perfusion measurements are related to measurements of renal plasma flow (RPF) by para-aminohippuric acid (PAH) plasma clearance and whether changes of kidney perfusion in response to treatment with telmisartan can be detected by MRI-ASL. METHODS: Twenty-four patients with metabolic syndrome and an estimated creatinine clearance according to Cockroft and Gault of > or =60 ml/min were included in the study. Kidney perfusion was assessed by MRI-ASL measurements of a single coronal kidney slice (with flow-sensitive alternating inversion recovery and true fast imaging with steady-state processing sequence) and by measurements of RPF using PAH plasma clearance before and after 2 weeks of treatment with the angiotensin receptor blocker telmisartan. All MRI-ASL examinations were performed on a 1.5 T scanner. RESULTS: Two weeks of therapy with telmisartan led to a significant increase of RPF (from 313 +/- 47 to 348 +/- 69 ml/min/m, P = 0.007) and MRI-ASL kidney perfusion measurements (from 253 +/- 20 to 268 +/- 25 ml/min/100 g, P = 0.020). RPF measurements were related with MRI-ASL kidney perfusion measurements (r = 0.575, P < 0.001). Changes of RPF measurements and changes of MRI-ASL kidney perfusion measurements in response to treatment with telmisartan revealed a close relationship when expressed in absolute terms (r = 0.548, P = 0.015) and in percentage changes (r = 0.514, P = 0.025). CONCLUSIONS: Perfusion measurement of a single coronal kidney slice by MRI-ASL is able to approximate kidney perfusion and to approximate changes in kidney perfusion due to pharmacological intervention.

The Virtual Family--development of surface-based anatomical models of two adults and two children for dosimetric simulations.

The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community.

Ultra-fast carotid CT-angiography: low versus standard volume contrast material protocol for a 128-slice CT-system.

OBJECTIVES: Noninvasive imaging is increasingly accepted for the evaluation of atherosclerotic disease of the carotid arteries. We sought to evaluate the feasibility of a low-contrast media volume protocol for carotid computed tomography angiography (CTA) using a 128-slice-spiral-computed tomography scanner with a gantry rotation time of 300 milliseconds. METHODS AND MATERIALS: Thirty consecutive patients underwent CTA for the evaluation of the carotid vessels, with a 128-section scanner. Fifteen patients were examined with a standard volume contrast injection protocol (group A): 80 mL of contrast material (CM) were injected at 5 mL/s using the test bolus method to assess individual transit time. Another 15 patients were examined with a low-volume contrast media protocol (group B): 30 mL CM were injected at 4 mL/s using bolus tracking to trigger the CTA acquisition. In both groups, contrast administration was followed by a saline flush. Image quality and segmental vascular enhancement as well as the presence and degree of arterial stenosis were independently evaluated by 2 radiologists. Venous enhancement and streak artifacts at the thoracic inlet because of highly concentrated CM in the subclavian veins were evaluated in both groups. Kappa statistic and Pearson correlation coefficient were used to quantify interobserver variability. Qualitative data were compared using the Wilcoxon signed rank test and student t test was used to investigate differences in segmental vessel attenuation. RESULTS: All studies were of diagnostic quality in both groups. Interobserver agreement was high (kappa = 0.82, group A; kappa = 0.78, group B). Attenuation measurement showed excellent interobserver correlation in both groups (r > 0.9). Mean enhancement values were slightly higher in group A, but without statistical significance when averaged for all segments (P = 0.06). Streak artifacts impaired evaluation of 13 adjacent arterial segments in 8 patients at the level of the thoracic inlet in group A. In group B, only 1 segment was rated insufficient by both radiologists. Venous enhancement was significantly lower in group B (P = 0.04). The low-contrast protocol proved to be the more robust method with constant high arterial enhancement, less streak artifacts at the thoracic inlet, and less venous overlay. CONCLUSION: Using the latest CT technology, optimal depiction of the craniocervical arteries can be archived with a low-volume (30 mL) CM protocol.

A retrospective study of enteroclysis in patients with manifest food allergy.

PURPOSE: The aim of this study was to investigate whether there are typical findings in enteroclysis of patients suffering from food allergy (FA). MATERIALS AND METHODS: Findings of enteroclysis of 26 FA patients were correlated with results of endoscopic and histologic examinations. In two patients allergen provocation was performed during enteroclysis. RESULTS: No specific mucosal pathologies were found without provocation. After provocation, low mucosal contrast adhesion was observed. CONCLUSION: Without provocation no specific alterations were found. However, enteroclysis may be used for monitoring of allergen challenge.

DNA double-strand breaks and their repair in blood lymphocytes of patients undergoing angiographic procedures.

OBJECTIVES: To adapt gamma-H2AX immunofluorescence microscopy to assessment of induction and repair of DNA double-strand breaks (DSBs) in peripheral blood lymphocytes in patients undergoing angiographic procedures. MATERIALS AND METHODS: The study was approved by the institutional ethics committee. After written informed patient consents were obtained, venous blood samples were taken from 19 patients (age 23-88 years) undergoing different angiographic procedures before, during, and after (10 minutes-24 hours) the examination. Individual DSB yields were visualized by detecting the phosphorylated variant of the histone H2AX (gamma-H2AX) in lymphocytes using fluorescence microscopy. Values were correlated with dose area product. Single in vitro irradiation with 50 mGy was performed in 14 and additional fractionated irradiation with 10 x 5 mGy over a time period corresponding to the angiography duration in 4 patients. The radiation doses to the blood delivered during angiography were estimated by comparing the number of DSBs after angiography with DSB yields obtained after in vitro irradiation. RESULTS: In all patients in vivo and in vitro irradiation increased the number of DSBs (0.03-1.50 per cell), even if very small doses were applied (minimum 338 microGy x m). Thereafter in both in vitro and in vivo a rapid loss of gamma-H2AX foci was observed. The number of DSBs showed a linear correlation to dose area product for specific examination regions (eg, R = 0.85, pelvic and leg arteries). Calculated radiation doses to blood delivered during angiography ranged from 2.2 to 99.9 mGy and increased if fractioned in vitro samples were used as calibration instead of single in vitro irradiations at the same total dose. CONCLUSIONS: gamma-H2AX immunofluorescence microscopy is a reliable and sensitive method for measuring the induction and repair of DNA damage caused by ionizing radiation during angiography. To estimate radiation doses delivered during procedures and to consider patients individual repair capacity, postangiography DSB-yields should be compared with DSB-yields after fractioned in vitro irradiation imitating examination conditions.

Influence of magnetic resonance contrast media on the activity of histamine inactivating enzymes.

RATIONALE AND OBJECTIVES: The observation that the intravenous application of gadolinium-based contrast media can lead to nephrogenic systemic fibrosis (NSF) has raised interest in their interactions with pathways. In this context, histamine is a focus because of its stimulating effect on fibrogenesis. In humans, histamine can be inactivated either by diamine oxidase (DAO) or by histamine N-methyltransferase (HMT), and numerous drugs are known to inhibit these enzymes. Therefore, it was the aim of this study to investigate whether magnetic resonance imaging contrast agents have an inhibitory effect on the enzymatic activities of DAO and HMT. MATERIALS AND METHODS: Seven gadolinium-based (gadoterate meglumine, gadoteridol, gadobutrol, gadobenate dimeglumine, gadopentetate dimeglumine, gadoxetate disodium, gadodiamide) and one manganese-containing (mangafodipir) contrast agents were tested in vitro. Following the preincubation of purified DAO and HMT with 0.1 to 10 mmol/L of the respective contrast medium, enzyme activities were determined using radiometric microassays. Enzyme activities measured in the absence of contrast agents and after preincubation with specific inhibitors of DAO and HMT, respectively, served as controls. RESULTS: The gadolinium-containing and manganese-containing contrast media tested did not show significant inhibition of the activities of DAO and HMT. No significant difference was observed between ionic and nonionic or between cyclic and linear gadolinium compounds. Preincubation of the enzymes with specific inhibitors led to complete inhibition of the respective enzymatic activity. CONCLUSION: The gadolinium-containing and manganese-based magnetic resonance imaging contrast media tested did not exhibit significant inhibition of histamine-inactivating enzymes at physiologically relevant concentrations.

Impact of 131I SPECT/spiral CT on nodal staging of differentiated thyroid carcinoma at the first radioablation.

UNLABELLED: The purpose of this study was to determine the diagnostic value of 131I SPECT/spiral CT (SPECT/CT) on nodal staging of patients with thyroid carcinoma at the first ablative radioiodine therapy. METHODS: Fifty-seven patients were studied using SPECT/CT 3-4 d after receiving 3.96+/-0.5 GBq of 131I for radioablation of thyroid remnants after a thyroidectomy for differentiated thyroid carcinoma. In addition to planar whole-body scintigraphy, SPECT/CT of the neck was performed using a hybrid camera combining a double-head SPECT camera with either a 2-slice (n=23) or a 6-slice (n=34) spiral CT scanner. The planar scans and the SPECT/CT images were evaluated for cervical tracer uptake independently of each other and of the clinical findings. RESULTS: SPECT/CT led to a revision of the original diagnosis in 28 of 143 cervical foci of radioiodine uptake seen on planar imaging. In particular, SPECT/CT reclassified as benign 6 of 11 lesions considered to be lymph node metastases and 11 of 15 lesions considered to be indeterminate. Furthermore, SPECT/CT allowed the identification of 11 lymph node metastases classified as thyroid remnant or as indeterminate on planar imaging. Based on this revision, SPECT/CT yielded a gain in information on nodal stage in 20 of the 57 patients studied (35%, P<0.03). SPECT/CT altered nodal stage from N0 to N1 in 2 of 20 patients and from indeterminate (Nx) to N1 in 6 of 30 patients. The result was a change in risk stratification conforming to the classification proposed by the International Union Against Cancer in 14 patients (25%). CONCLUSION: SPECT/CT determines lymph node involvement at radioablation performed for thyroid cancer more accurately than does planar imaging. SPECT/CT may alter management in roughly one quarter of patients with thyroid carcinoma by upstaging or downstaging their disease.

Nephrotoxicity of iso-osmolar iodixanol compared with nonionic low-osmolar contrast media: meta-analysis of randomized controlled trials.

PURPOSE: To compare the nephrotoxicity of iso-osmolar iodixanol with that of nonionic low-osmolar contrast media (CM) (LOCM) in randomized clinical trials. MATERIALS AND METHODS: This meta-analysis was conducted with a systematic search of MEDLINE, EMBASE, BIOSIS, Web of Science, ISI Web of Knowledge, Current Contents Medizin, Cochrane Library (until August 2007), trial registers, conference proceedings, and reference lists to identify studies and with requests from all manufacturers of CM for unidentified studies. Randomized controlled trials assessing serum creatinine levels before and after intravascular application of iodixanol or LOCM were included. The primary outcome measures were the incidence of contrast medium-induced nephropathy (CIN) and change in serum creatinine levels. RESULTS: Twenty-five trials were included. Iodixanol did not significantly reduce the risk of CIN (relative risk [RR], 0.80; 95% confidence interval [CI]: 0.61, 1.04; weighted mean difference in serum creatinine increase, 0.01 mg/dL [0.88 mumol/L]; 95% CI: -0.01, 0.03). There was no significant risk reduction after intravenous administration of the CM (RR, 1.08; 95% CI: 0.62, 1.89); subgroup with preexisting renal insufficiency (RR, 1.07; 95% CI: 0.56, 2.02) or after intraarterial administration (RR, 0.68; 95% CI: 0.46, 1.01); subgroup with preexisting renal insufficiency (RR, 0.59; 95% CI: 0.33, 1.07). However, in patients with intraarterial administration and renal insufficiency, the risk of CIN was greater for iohexol than for iodixanol (RR, 0.38; 95% CI: 0.21, 0.68), whereas there was no difference between iodixanol and the other (noniohexol) LOCM (RR, 0.95; 95% CI: 0.50, 1.78). CONCLUSION: Iodixanol is not associated with a significantly reduced risk of CIN compared with the LOCM pooled together. However, in patients with intraarterial administration and renal insufficiency, iodixanol is associated with a reduced risk of CIN compared with iohexol, whereas no significant difference between iodixanol and other LOCM could be found.

Resectability of pancreatic adenocarcinoma: assessment using multidetector-row computed tomography with multiplanar reformations.

The purpose was to assess capabilities of the multidetector-row computed tomography (MDCT) with multiplanar reformations (MPR) for predicting of pancreatic adenocarcinoma resectability. Forty-eight patients deemed to have resectable pancreatic adenocarcinoma after assessment using biphasic MDCT with MPRs underwent surgery for potential tumor resection. Imaging findings were retrospectively evaluated for tumor resectability and correlated with surgical and pathological results. Curative resection was successful in 44 of 48 patients. The positive predictive value for tumor resectability made up 91% with four false-negative results. The reasons for unresectability were venous involvement (1), small liver metastases (2) and peritoneal involvement associated with small metastases to lymph nodes (1). MDCT yielded a negative predictive value of 99% (286 of 288 vessels) for detection of vascular invasion. Our results indicate the tendency towards improved prediction of resectability using MDCT compared to single-detector CT.

Functional cardiac CT imaging: a new contrast application strategy for a better visualization of the cardiac chambers.

PURPOSE: Evaluation of a new protocol for Dual-source CT contrast-enhanced cardiac imaging for better visualization of right ventricle structures. METHODS: A total of 106 patients were included in this prospective, controlled study. The control group (n=53) underwent our clinic's standard procedure for contrast-enhanced imaging of coronary arteries. The study group (n=53) was imaged using a protocol with the dual flow injection protocol in which the saline chaser bolus contained 20% contrast media. The images were analyzed for mean density values using defined ROIs in the septum and both ventricles. In addition the data sets were semi-quantitatively evaluated for visual delineation between right ventricle and septum. To investigate whether this new protocol influenced the visualization of coronary arteries, mean density was also measured in the right and left coronary artery. RESULTS: The dual flow concept allows for a statistically significant better delineation of the septum in Dual-source cardiac computed tomography for both the quantitative and semi-quantitative analyses. Also, the dual flow concept allows for statistically relevant higher coronary attenuation. CONCLUSION: Using a saline chaser containing 20% contrast medium improves septal delineation for functional ventricular analysis as well as unimpaired coronary visualization.

Direct MR galactography: feasibility study.

PURPOSE: To compare T1- and T2-weighted direct magnetic resonance (MR) galactography, indirect MR galactography, and conventional galactography in women with pathologic nipple discharge. MATERIALS AND METHODS: The study was approved by the institutional review board. Written informed consent was obtained from all patients. Twenty-three women (age range, 30-85 years) with pathologic nipple discharge and pathologic conventional galactographic findings underwent physical examination, ultrasonography, and MR imaging before surgery. A T2-weighted sequence of the affected breast was performed before (indirect MR galactography), and T1- and T2-weighted sequences were performed after (direct MR galactography), gadopentetate dimeglumine was injected into the discharging duct. MR galactographic findings were analyzed and compared with conventional galactographic findings. Sequences used were T2-weighted three-dimensional constructive interference in steady state (CISS), T1-weighted volumetric interpolated breath-hold examination (VIBE), and T1-weighted fast low-angle shot (FLASH). RESULTS: The 23 patients had a total of 57 findings at conventional galactography. Indirect MR galactography with CISS showed pathologic findings in eight (42%) of 19 patients and showed 15 (33%) of 46 of all findings. Direct MR galactography with CISS showed pathologic findings in 23 (100%) of 23 patients and 47 (82%) of 57 of all findings, that with VIBE showed pathologic findings in 19 (83%) of 23 patients and 38 (67%) of 57 of all findings, and that with FLASH showed pathologic findings in 16 (100%) of 16 patients and 31 (80%) of 39 of all findings. There was a significant (P < .01) difference between indirect MR galactography and all direct MR galactography sequences in the detection of ductal disease. Eight (35%) of 23 women showed additional findings at direct MR galactography in comparison with standard MR imaging sequences. CONCLUSION: MR galactography has the potential to be used in the diagnostic work-up of pathologic nipple discharge. Direct MR galactography shows more disease than does indirect MR galactography. The highest detection rate for ductal disease compared with that at conventional galactography was found with the direct MR galactography CISS and FLASH sequences.

Contrast-enhanced T1-weighted fluid-attenuated inversion-recovery BLADE magnetic resonance imaging of the brain: an alternative to spin-echo technique for detection of brain lesions in the unsedated pediatric patient?

RATIONALE AND OBJECTIVES: We compared contrast-enhanced T1-weighted magnetic resonance (MR) imaging of the brain using different types of data acquisition techniques: periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER, BLADE) imaging versus standard k-space sampling (conventional spin-echo pulse sequence) in the unsedated pediatric patient with focus on artifact reduction, overall image quality, and lesion detectability. MATERIALS AND METHODS: Forty-eight pediatric patients (aged 3 months to 18 years) were scanned with a clinical 1.5-T whole body MR scanner. Cross-sectional contrast-enhanced T1-weighted spin-echo sequence was compared to a T1-weighted dark-fluid fluid-attenuated inversion-recovery (FLAIR) BLADE sequence for qualitative and quantitative criteria (image artifacts, image quality, lesion detectability) by two experienced radiologists. Imaging protocols were matched for imaging parameters. Reader agreement was assessed using the exact Bowker test. RESULTS: BLADE images showed significantly less pulsation and motion artifacts than the standard T1-weighted spin-echo sequence scan. BLADE images showed statistically significant lower signal-to-noise ratio but higher contrast-to-noise ratios with superior gray-white matter contrast. All lesions were demonstrated on FLAIR BLADE imaging, and one false-positive lesion was visible in spin-echo sequence images. CONCLUSION: BLADE MR imaging at 1.5 T is applicable for central nervous system imaging of the unsedated pediatric patient, reduces motion and pulsation artifacts, and minimizes the need for sedation or general anesthesia without loss of relevant diagnostic information.

Right heart: split-bolus injection of diluted contrast medium for visualization at coronary CT angiography.

PURPOSE: To retrospectively compare a split-bolus contrast medium injection protocol with a biphasic and a monophasic protocol in terms of visualization of the right and left heart, contrast medium-related streak artifacts, and level of attenuation in the cardiac chambers and coronary arteries at coronary computed tomographic (CT) angiography. MATERIALS AND METHODS: The human research committee approved this HIPAA-compliant study and waived informed consent. Seventy-five patients had undergone 64-section coronary CT angiography: 25 were injected by using a monophasic, contrast-medium-only protocol with a single-syringe injector; 25 were injected by using a biphasic protocol with a dual-syringe injector; and 25 were injected by using a split-bolus protocol with a dual-syringe injector and an initial bolus of contrast medium followed by 50 mL of a 70%:30% saline-to-contrast medium mixture and a 30-mL saline chaser. Two radiologists rated the visualization of right and left heart structures and the degree of streak artifacts. One observer performed attenuation measurements of the cardiac chambers and of the coronary arteries. Data were analyzed with one-way analysis of variance and Duncan post-hoc multiple comparison procedures. RESULTS: Data for 27 women and 48 men (mean age, 62 years) were included. Mean contrast medium attenuation in the right heart was significantly (P < .001) higher in the split-bolus group than in the biphasic injection group but was significantly (P < .001) lower than in the monophasic injection group. For the left heart and the coronary arteries, there were no significant differences among the three groups. Artifacts occurred less frequently (P < .001) in the biphasic and split-bolus groups than in the monophasic group. Visualization of right heart structures was rated significantly (P < .05) better in the split-bolus group than in the two other groups, while there was no difference for visualization of left heart structures. CONCLUSION: Split-bolus injection provides sufficient attenuation for visualization of the right heart, while streak artifacts from high-attenuation contrast material can generally be avoided and arterial attenuation is maintained.

Thin-slice MDCT of the neck: impact on cancer staging.

OBJECTIVE: The objective of this study was to compare thin-slice multiplanar evaluation and conventional 3-mm axial evaluation of head and neck MDCT in tumor staging. MATERIALS AND METHODS: Ninety-six patients with histologically proven squamous cell carcinoma were evaluated independently, once using 3-mm axial images and once using 1-mm interactive multiplanar reformation (MPR) images. Tumor stage was assessed with both methods; histology served as the reference. Thirty-seven patients with hypopharyngeal and laryngeal tumors had en bloc resection, allowing direct comparison of tumor infiltration into designated anatomic structures. Two examiners independently assessed the data sets. Interobserver agreement was tested with a modified kappa test. The Wilcoxon signed rank test with continuity correction was applied to test the null hypothesis, which postulates the equality of both methods. The chi-square test was applied to compare the number of correctly classified tumors for the two methods and readers. RESULTS: Interobserver agreement was high (kappa = 0.88-0.91). Both methods allowed accurate tumor staging, and no significant differences between the two methods were found (reader A, p = 0.61; reader B, p = 1). With MPR assessment, more anatomic structures were rated positive for tumor infiltration, but diagnostic accuracy did not differ significantly in the subgroup of patients with histologic correlation from en bloc resection. CONCLUSION: Conventional 3-mm axial evaluation of head and neck MDCT proved to be sufficient in tumor staging.

[Suggestions for prevention of adverse reactions after intravasal administration of iodinated contrast media]. / Empfehlungen zur Prophylaxe der Nebenwirkungen bei intravasaler Applikation jodhaltiger Kontrastmittel. Suggestions for prevention of adverse reactions after intravasal administration of iodinated contrast media.

Iodinated contrast media are widely used in computed tomography and angiography. Adverse reactions such as contrast-medium induced nephropathy (CIN), anaphylactoid reactions and iodine-induced thyrotoxicosis are associated with intravasal administration of contrast agents. Iodinated contrast agents are generally considered to be safe, but in rare cases they can cause severe life threatening situations. In this review we present an overview about the incidence, pathways, and risk factors of adverse reactions. Simple schemes including hydration protocols for prevention of CIN, medication for prophylaxis of iodine-induced thyrotoxicosis with thyreostatics and anaphylactoid reactions with histamine antagonists and corticosteroids are suggested.

[Diagnosis of fungal pneumonia in the thoracic CT]. / Diagnose der Pilzpneumonie in der Thorax-CT CT scan findings of fungal pneumonia.

The importance of fungal infection of the lung in immunocompromised patients has increased substantially during the last decades. Numerically the most patients are those with neutropenia, e.g., patients with malignancies or solid organ and stem cell transplantation, chemotherapy, corticosteroid use and HIV infection. Although fungal infections can occur in immunocompetent patients, their frequency in this population is rare. The clinical symptoms such as fever accompanied with non-productive cough are unspecific. In some patients progression to hypoxemia and dyspnea may occur rapidly. In spite of improved antifungal therapy morbidity and mortality of these infections are still high. Therefore an early and non-invasive diagnosis is very important. That is why CT and even better High-Resolution-CT (HR-CT) is a very important modality in examining immunocompromised patients with a probability of fungal infection. CT is everywhere available and, as a non-invasive method, able to give the relevant diagnose efficiently. This paper should give an overview about the radiologic findings and possible differential diagnosis of diverse pulmonary fungal infections in CT. Pneumonias caused by Aspergillus, Cryptococcus, Candida, Histoplasma, Mucor and Geotrichum capitatum are illustrated.

[Differential diagnosis of focal lesions of the kidney in CT and MRT]. / Differentialdiagnose fokaler Nierenläsionen in CT und MRT.

The great majority of renal masses are found incidentally as a result of the use of ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI). If ultrasonography is not diagnostic CT or MRI should be initiated to differentiate lesions of the kidney that need surgical intervention from those that do not and from those that need follow-up examinations. Cystic renal masses are characterized by using the Bosniak classification, including category IIF. In solid Lesions of the kidney first non-surgical lesions as well as lymphoma, renal infarction and nephritis should be excluded. Identifying fatty components in renal lesions is very important because in angiomyolipoma they are almost always present. CT and MRI are exellent for tumor detection. Careful evaluation of imaging finding combined with the patient's history should assist the radiologist in making the proper diagnosis or recommending the appropriate treatment in most cases. This article provides a review about renal masses, the imaging methods for their evaluation and their characteristic features at CT and MR imaging. Different lesions are demonstrated like xantogranulomatous pyelonephritis, acute pyelonephritis, renal infarction, lymphoma, angiomyolipoma, renal oncocytoma, cystic lesion and polycystic disease the kidney, echinococcosis, renal cystadenoma, metastases, renal cell carcinoma (RCC), and multiple bilateral RCC in patients with Hippel-Lindau-Syndrome. This article should help to differentiate complex cystic lesions of the kidney by using the Bosniak-classification, especially Bosniak Category IIF. Solid masses should be characterized and the major question to be answered is whether the mass represents a surgical or nonsurgical lesion or if follow-up studies are necessary.

[The von Meyenburg complex]. / Der von Meyenburg Komplex.

The von Meyenburg complex (VMC) describes bile duct hamartomas and presents a rare, benign incidental finding in liver imaging. We report on a 61-year-old man, who was referred for a follow up study 14 years after remission of Hodgkin's disease. Computed tomography (CT) revealed multiple hypodense lesions throughout the liver, primary suggesting recurrent Hodgkin's disease. Previous CT-examinations, which were obtained at a later date, showed those Lesions in identical distribution and morphology over the years, leading to diagnosis of multiple bile duct hamartomas (VMC). Making imaging-based diagnosis of VMC including ultrasound, CT and magnetic resonance imaging is a challenging task for the radiologist. Based on literature research findings, the impact of different modalities in the diagnostic work-up of VMC is discussed.

[Hypoxic injury of all deep nuclei of the brain--a case report from computed tomography]. / Hypoxischer Schaden aller tiefen Kerngebiete des Gehirns--ein Fallbericht aus der Computertomographie.

Though being inferior to magnetic resonance imaging, computed tomography (CT) of the brain is the most frequently applied imaging modality in the diagnostic workup of acute cerebral Ischaemia. We report on a case of a comatose 53-year-old man who was brought to the emergency room after cardiopulmonary resuscitation. The CT of the brain showed a diffuse brain oedema with an explicit hypodense demarcation of all deep nuclei.