D Blondin

Non-enhanced 3D MR angiography of the lower extremity using ECG-gated TSE imaging with non-selective refocusing pulses--initial experience.

PURPOSE To evaluate non-enhanced 3D MR angiography using turbo spin echo (TSE) imaging with non-selective refocusing pulses (NATIVE SPACE MRA) for the visualization of the arteries of the lower extremity. MATERIALS AND METHODS Three-station imaging (iliac arteries, femoral arteries, arteries of the lower leg) was performed in 8 healthy volunteers and 3 patients with peripheral artery disease (PAD) using a 1.5 T MR scanner. In 8 healthy volunteers, 4 different acquisition schemes were performed with the following imaging parameters: S 1: acquisition with every heartbeat (RR = 1), spoiler gradient of 25 % (SG = 25 %); S 2: RR = 1, SG = 0 %; S 3: RR = 2, SG = 25 %; S 4: RR = 2, SG = 0 %. The subjective image quality on a 4-point-scale (4 = excellent to 1 = not diagnostic) and relative SNR were assessed. In 3 patients with peripheral artery disease (PAD), SPACE MRA was performed for assessment of stenosis. RESULTS The mean subjective image quality was significantly lower for the iliac arteries compared to the femoral arteries and arteries of the lower leg (p < 0.0001). The subjective image quality for acquisition scheme S 1 was significantly lower than the image quality for S 3 and S 4 for the iliac arteries (p < 0.01), while the subjective image quality for acquisition scheme S 2 was significantly lower than S 3 and S 4 for the femoral arteries and the arteries of the lower leg (p < 0.01). The relative SNR was significantly higher for acquisition schemes S 3 and S 4 as compared to S 1 and S 2 (p < 0.0001) for all regions. SPACE MRA disclosed 7 significant stenoses in 3 PAD patients. CONCLUSION ECG-gated SPACE MRA is a promising imaging technique for non-enhanced assessment of the arteries of the lower extremity.

Nonenhanced MR angiography techniques

Especially in regard to the potential risks for the development of nephrogenic systemic fibrosis (NSF) following the administration of Gadolinium-based contrast material, nonenhanced MR angiography (MRA) methods are becoming ever more important. Besides well-established time-of-flight (TOF) and phase-contrast (PC) MRA, alternative imaging techniques based on balanced steady-state free precession (bSSFP) and turbo-spin-echo (TSE) sequences are increasingly used in combination with or without arterial spin labeling (ASL) strategies. This article provides an overview of the principles and clinical values of different nonenhanced MRA techniques. In addition, recent nonenhanced MRA developments are presented.

Prävalenz und klinische Bedeutung inzidenteller Herzbefunde im nicht EKG-getriggerten Thorax-CT

BACKGROUND The purpose of this study was to evaluate the prevalence and clinical significance of incidental cardiac findings in non-ECG-gated chest CT. PATIENTS AND METHODS Non-ECG-gated chest CT examinations of 300 patients were retrospectively analyzed for incidental cardiac findings. Subsequently, these findings were evaluated for their clinical relevance by a cardiologist. RESULTS A total of 107 out of 300 examined patients had 174 incidental cardiac findings including coronary calcification (90), aortic/mitral valve calcification (42), iatrogenic changes (23), pericardial effusion (6), dilatation of the heart (4), myocardial changes (3), thrombus in the left ventricle (2), constrictive pericarditis (2) and atrial myxoma (1). Of the cardiac findings 51% were described in the written report and in 53 out of the 107 patients the cardiac findings were unknown. Newly detected incidental findings from 8 patients were rated as clinically significant: pericardial effusion (4), constrictive pericarditis (1), thrombus in the left ventricle (1), atrial myxoma (1) and dilatation of the heart (1). CONCLUSION Incidental cardiac findings are frequent in non-ECG-gated chest CT and may have a high clinical relevance.

Knöcherne Pathologien der Metacarpophalangeal-Gelenke bei früher rheumatoider Arthritis: Vergleich zwischen MRT und hochauflösender SPECT

AIM Comparison of MRI with a newly developed high-resolution multi-pinhole single photon emission computed tomography (MPH-SPECT) regarding the detection of bony pathologies of the metacarpophalangeal (MCP) joints in patients with early rheumatoid arthritis (ERA). MATERIALS AND METHODS The clinically dominant hand of 15 patients with ERA (disease duration 6 months) was examined using MRI and MPH-SPECT. The evaluation of MRI was achieved according to RAMRIS criteria and for the MPH SPECT regarding pathological tracer uptake and distribution. Image fusions of MRI and MPH-SPECT were provided and the two methods were compared. RESULTS In MRI 12 of 15 patients showed arthritic joint pathologies, while 8 patients exhibited soft tissue and bony changes. 4 patients had only soft tissue inflammation (synovitis) with a normal bone signal. In MPH-SPECT 10 of 15 patients showed pathologically increased bone metabolism. The fusion images presented a high agreement of the pathological changes in both methods, while areas with increased bone metabolism were not only present in the case of erosions, but also in the case of bone edema. In 2 patients increased bone metabolism was detectable in areas of MR tomographic normal bone, while a clear surrounding synovitis was present in each case here. CONCLUSION The comparison of MPH-SPECT with MRI proves that the latter is a sensitive procedure for the detection of bony pathologies of MCP joints in ERA. A normal bone signal in MRI does not exclude early changes in bone metabolism in cases of severe synovialitis.

[Prevalence and clinical significance of incidental cardiac findings in non-ECG-gated chest CT scans].

BACKGROUND The purpose of this study was to evaluate the prevalence and clinical significance of incidental cardiac findings in non-ECG-gated chest CT. PATIENTS AND METHODS Non-ECG-gated chest CT examinations of 300 patients were retrospectively analyzed for incidental cardiac findings. Subsequently, these findings were evaluated for their clinical relevance by a cardiologist. RESULTS A total of 107 out of 300 examined patients had 174 incidental cardiac findings including coronary calcification (90), aortic/mitral valve calcification (42), iatrogenic changes (23), pericardial effusion (6), dilatation of the heart (4), myocardial changes (3), thrombus in the left ventricle (2), constrictive pericarditis (2) and atrial myxoma (1). Of the cardiac findings 51% were described in the written report and in 53 out of the 107 patients the cardiac findings were unknown. Newly detected incidental findings from 8 patients were rated as clinically significant: pericardial effusion (4), constrictive pericarditis (1), thrombus in the left ventricle (1), atrial myxoma (1) and dilatation of the heart (1). CONCLUSION Incidental cardiac findings are frequent in non-ECG-gated chest CT and may have a high clinical relevance.

Gadofosveset-enhanced MR imaging for the preoperative evaluation of potential living kidney donors: correlation with intraoperative findings.

PURPOSE The purpose of this study was to evaluate the blood pool contrast agent gadofosveset for MR angiography (MRA) of the renal vasculature in living kidney donors (LKD). MATERIALS AND METHODS Of the 28 consecutive potential LKDs (13 men, 15 women; mean age 55.14 years ± 11.97) initially included in this prospective study, 20 patients underwent surgery and were considered for further evaluation. 7 acquisitions of a 3D T 1-weighted FLASH sequence were performed following administration of gadofosveset for the assessment of the vascular anatomy and collecting system at predefined time points at 1.5 T. All MR exams were prospectively analyzed by 2 radiologists in consensus mode prior to surgery. In addition, ROI-based relative SNR measurements were performed in the vena cava inferior and abdominal aorta. RESULTS MR image acquisition was completed in all 20 potential living donors. In 8 donors an additional CT scan was available for further comparison with the collateral anatomy, resulting in a total of 28 analyzed kidneys. MRA disclosed 36 renal arteries, since 8 accessory arteries were found in 8 subjects. One accessory artery and one case of fibromuscular dysplasia were missed by MRA. The venous anatomy and the collecting system were assessed correctly with MRI. In addition, MRI diagnosed two renal cell carcinomas. The overall sensitivity and positive predictive value of gadofosveset-enhanced MRI on a per kidney basis were 92.9 % and 100 %, respectively. CONCLUSION Gadofosveset enables accurate evaluation of potential LKDs.

MR-Diagnostik des Abdomens in der Schwangerschaft

Sonography is still the method of choice for imaging diseases in pregnant women. The changed physiognomy of the women increases the known limitations of sonography while the advantages of MRI (large field of view, excellent soft-tissue contrast, sensitive diagnosis of edema) are not affected. The available sequences allow the differentiation of various pathologies. Most of these can frequently be visualized without intravenous administration of contrast material. Although the significance of techniques like DWI and ASL has not yet been explored, initial descriptions are promising and MR imaging in pregnancy will be increasingly important in the future. Therefore, knowledge of the most frequent diseases in pregnancy and their image appearance is relevant to radiologists. The advantages of MRI in comparison to sonography and its important role in imaging pathologies of the acute abdomen in pregnancy are illustrated and discussed.

[Case-based interactive PACS learning: introduction of a new concept for radiological education of students].

PURPOSE Medical curricula are currently being reformed in order to establish superordinated learning objectives, including, e.g., diagnostic, therapeutic and preventive competences. This requires a shifting from traditional teaching methods towards interactive and case-based teaching concepts. Conceptions, initial experiences and student evaluations of a novel radiological course Co-operative Learning In Clinical Radiology (CLICR) are presented in this article. MATERIALS AND METHODS A novel radiological teaching course (CLICR course), which combines different innovative teaching elements, was established and integrated into the medical curriculum. Radiological case vignettes were created for three clinical teaching modules. By using a PC with PACS (Picture Archiving and Communication System) access, web-based databases and the CASUS platform, a problem-oriented, case-based and independent way of learning was supported as an adjunct to the well established radiological courses and lectures. Student evaluations of the novel CLICR course and the radiological block course were compared. RESULTS Student evaluations of the novel CLICR course were significantly better compared to the conventional radiological block course. Of the participating students 52% gave the highest rating for the novel CLICR course concerning the endpoint overall satisfaction as compared to 3% of students for the conventional block course. The innovative interactive concept of the course and the opportunity to use a web-based database were favorably accepted by the students. Of the students 95% rated the novel course concept as a substantial gain for the medical curriculum and 95% also commented that interactive working with the PACS and a web-based database (82%) promoted learning and understanding. CONCLUSION Interactive, case-based teaching concepts such as the presented CLICR course are considered by both students and teachers as useful extensions to the radiological course program. These concepts fit well into competence-oriented curricula.

Moderne CT- und PET/CT-Bildgebung der Leber

Computed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.ZusammmenfassungDie Computertomographie (CT) ist heute breit verfügbar und stellt eine wichtige und schnelle Methode zur Diagnostik akuter Lebererkrankungen, der Artdiagnostik fokaler Leberläsionen und der Planung interventioneller Therapiemaßnahmen sowie der postinterventionellen Kontrolle dar. In den letzten Jahren hat die CT trotz des zunehmenden Stellenwerts der Magnetresonanztomographie (MRT) nicht an Bedeutung verloren. Durch den Einsatz unterschiedlicher Kontrastmittelphasen kann meist eine gute Charakterisierung von Raumforderungen erfolgen. Bei der Diagnostik des hepatozellulären Karzinoms (HCC) sollte beispielsweise immer ein triphasisches Untersuchungsprotokoll angewendet werden. Mit Einführung der Dual-energy-CT hat die Sensitivität in der Darstellung hyper- und hypovaskularisierter Leberläsionen zugenommen. Ebenfalls ist es durch virtuelle native Bilder möglich geworden, auf eine zusätzliche native Bildgebung zu verzichten, wodurch die Strahlenexposition des Patienten vermindert werden kann. Die PET/CT hat in der onkologischen Bildgebung den Vorteil, dass nahezu der gesamte Körper des Patienten abgebildet wird. Hier ist auch die Hauptindikation der PET/CT zu sehen (Ganzkörperstaging). Bei rein hepatischer Fragestellung hat die FDG-PET/CT unter Verwendung diagnostischer CT-Daten zwar eine höhere Genauigkeit als die CT alleine, ist der MRT jedoch unterlegen.AbstractComputed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.

[Modern CT and PET/CT imaging of the liver].

Computed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.ZusammmenfassungDie Computertomographie (CT) ist heute breit verfügbar und stellt eine wichtige und schnelle Methode zur Diagnostik akuter Lebererkrankungen, der Artdiagnostik fokaler Leberläsionen und der Planung interventioneller Therapiemaßnahmen sowie der postinterventionellen Kontrolle dar. In den letzten Jahren hat die CT trotz des zunehmenden Stellenwerts der Magnetresonanztomographie (MRT) nicht an Bedeutung verloren. Durch den Einsatz unterschiedlicher Kontrastmittelphasen kann meist eine gute Charakterisierung von Raumforderungen erfolgen. Bei der Diagnostik des hepatozellulären Karzinoms (HCC) sollte beispielsweise immer ein triphasisches Untersuchungsprotokoll angewendet werden. Mit Einführung der Dual-energy-CT hat die Sensitivität in der Darstellung hyper- und hypovaskularisierter Leberläsionen zugenommen. Ebenfalls ist es durch virtuelle native Bilder möglich geworden, auf eine zusätzliche native Bildgebung zu verzichten, wodurch die Strahlenexposition des Patienten vermindert werden kann. Die PET/CT hat in der onkologischen Bildgebung den Vorteil, dass nahezu der gesamte Körper des Patienten abgebildet wird. Hier ist auch die Hauptindikation der PET/CT zu sehen (Ganzkörperstaging). Bei rein hepatischer Fragestellung hat die FDG-PET/CT unter Verwendung diagnostischer CT-Daten zwar eine höhere Genauigkeit als die CT alleine, ist der MRT jedoch unterlegen.AbstractComputed tomography (CT) is now widely available and represents an important and rapid method for the diagnostics of acute liver disease, characterization of focal liver lesions, planning of interventional therapy measures and postintervention control. In recent years CT has not become less important despite the increasing value of magnetic resonance imaging (MRI). By the use of different contrast medium phases good characterization of space-occupying lesions can be achieved. For the diagnostics of hepatocellular carcinoma (HCC) a triphasic examination protocol should always be implemented. The introduction of dual energy CT increased the sensitivity of imaging of hypervascularized and hypovascularized liver lesions and by the use of virtual native imaging it has become possible to avoid additional native imaging which reduces the x-ray exposition of patients. Positron emission tomography (PET) has an advantage for imaging in oncology because nearly the complete body of the patient can be screened and this is the main indication for PET/CT (whole-body staging). For purely hepatic problems 18F-fluorodeoxyglucose (FDG)-PET/CT using diagnostic CT data has a higher precision than CT alone but is inferior to MRI.