Skip to main content
Erschienen in: Journal of Nuclear Cardiology 2/2013

01.04.2013 | Review Article

CT imaging of myocardial perfusion: Possibilities and perspectives

verfasst von: Alexander Becker, MD, Christoph Becker, MD

Erschienen in: Journal of Nuclear Cardiology | Ausgabe 2/2013

Einloggen, um Zugang zu erhalten

Abstract

Functional imaging in patients with suspected or known coronary artery disease (CAD) is crucial for the identification of patients who could benefit from coronary revascularization. Several studies demonstrated the high diagnostic accuracy of Single-photon-emission computed tomography myocardial perfusion imaging, stress perfusion magnetic resonance imaging, and of invasive FFR measurements for the detection of hemodynamic relevant stenosis. Cardiac computed tomography (CT) used to be limited to coronary angiography (CTA); current guidelines recommend CTA only for the exclusion of CAD. Technological advances now offer the possibility to assess myocardial perfusion by computed tomography (CT-MPI). Though different acquisition protocols and post-processing algorithms still have to be evaluated, initial clinical studies could already show a diagnostic accuracy comparable to the established imaging modalities. Thus, cardiac CT may offer a combined approach of anatomical and functional imaging. Beside the need for further studies, especially on the prognostic value of CT-MPI to stratify future cardiovascular events, the comparatively high radiation exposure and additional administration of contrast agent has to be taken in account.
Literatur
1.
Zurück zum Zitat Roger VL, Go AS, Lloyd-Jones DM, Benjamin EJ, Berry JD, Borden WB, et al. Heart disease and stroke statistics—2012 update: A report from the American Heart Association. Circulation 2012;125:e2-220.PubMedCrossRef Roger VL, Go AS, Lloyd-Jones DM, Benjamin EJ, Berry JD, Borden WB, et al. Heart disease and stroke statistics—2012 update: A report from the American Heart Association. Circulation 2012;125:e2-220.PubMedCrossRef
2.
Zurück zum Zitat Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O’Gara P, et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Circulation 2010;122:e525-55.PubMedCrossRef Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O’Gara P, et al. ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Circulation 2010;122:e525-55.PubMedCrossRef
3.
Zurück zum Zitat Tonino PA, De Bruyne B, Pijls NH, Siebert U, Ikeno F, van’ t Veer M, et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. N Engl J Med 2009;360:213-24.PubMedCrossRef Tonino PA, De Bruyne B, Pijls NH, Siebert U, Ikeno F, van’ t Veer M, et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. N Engl J Med 2009;360:213-24.PubMedCrossRef
4.
Zurück zum Zitat Shaw LJ, Berman DS, Maron DJ, Mancini GB, Hayes SW, Hartigan PM, et al. Optimal medical therapy with or without percutaneous coronary intervention to reduce ischemic burden: Results from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial nuclear substudy. Circulation 2008;117:1283-91.PubMedCrossRef Shaw LJ, Berman DS, Maron DJ, Mancini GB, Hayes SW, Hartigan PM, et al. Optimal medical therapy with or without percutaneous coronary intervention to reduce ischemic burden: Results from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial nuclear substudy. Circulation 2008;117:1283-91.PubMedCrossRef
5.
Zurück zum Zitat Rocha-Filho JA, Blankstein R, Shturman LD, Bezerra HG, Okada DR, Rogers IS, et al. Incremental value of adenosine-induced stress myocardial perfusion imaging with dual-source CT at cardiac CT angiography. Radiology 2010;254:410-9.PubMedCrossRef Rocha-Filho JA, Blankstein R, Shturman LD, Bezerra HG, Okada DR, Rogers IS, et al. Incremental value of adenosine-induced stress myocardial perfusion imaging with dual-source CT at cardiac CT angiography. Radiology 2010;254:410-9.PubMedCrossRef
6.
Zurück zum Zitat Arbab-Zadeh A, Miller JM, Rochitte CE, Dewey M, Niinuma H, Gottlieb I, et al. Diagnostic accuracy of computed tomography coronary angiography according to pre-test probability of coronary artery disease and severity of coronary arterial calcification. The CORE-64 (Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography) International Multicenter Study. J Am Coll Cardiol 2012;59:379-87.PubMedCrossRef Arbab-Zadeh A, Miller JM, Rochitte CE, Dewey M, Niinuma H, Gottlieb I, et al. Diagnostic accuracy of computed tomography coronary angiography according to pre-test probability of coronary artery disease and severity of coronary arterial calcification. The CORE-64 (Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography) International Multicenter Study. J Am Coll Cardiol 2012;59:379-87.PubMedCrossRef
7.
Zurück zum Zitat Hulten EA, Bittencourt MS, Ghoshhajra B, Blankenstein R. Stress CT perfusion: Coupling coronary anatomy with physiology. J Nucl Cardiol 2012;19:588-600.PubMedCrossRef Hulten EA, Bittencourt MS, Ghoshhajra B, Blankenstein R. Stress CT perfusion: Coupling coronary anatomy with physiology. J Nucl Cardiol 2012;19:588-600.PubMedCrossRef
8.
Zurück zum Zitat Nikolaou K, Knez A, Sagmeister S, Wintersperger BJ, Boekstegers P, Steinbeck G, et al. Assessment of myocardial infarctions using multidetector-row computed tomography. J Comput Assist Tomogr 2004;28:286-92.PubMedCrossRef Nikolaou K, Knez A, Sagmeister S, Wintersperger BJ, Boekstegers P, Steinbeck G, et al. Assessment of myocardial infarctions using multidetector-row computed tomography. J Comput Assist Tomogr 2004;28:286-92.PubMedCrossRef
9.
Zurück zum Zitat Krombach GA, Niendorf T, Gunther RW, Mahnken AH. Characterization of myocardial viability using MR and CT imaging. European radiology 2007;17:1433-44.PubMedCrossRef Krombach GA, Niendorf T, Gunther RW, Mahnken AH. Characterization of myocardial viability using MR and CT imaging. European radiology 2007;17:1433-44.PubMedCrossRef
10.
Zurück zum Zitat Habis M, Capderou A, Ghostine S, Daoud B, Caussin C, Riou JY, et al. Acute myocardial infarction early viability assessment by 64-slice computed tomography immediately after coronary angiography: Comparison with low-dose dobutamine echocardiography. J Am Coll Cardiol 2007;49:1178-85.PubMedCrossRef Habis M, Capderou A, Ghostine S, Daoud B, Caussin C, Riou JY, et al. Acute myocardial infarction early viability assessment by 64-slice computed tomography immediately after coronary angiography: Comparison with low-dose dobutamine echocardiography. J Am Coll Cardiol 2007;49:1178-85.PubMedCrossRef
11.
Zurück zum Zitat Ruzsics B, Schwarz F, Schoepf UJ, Lee YS, Bastarrika G, Chiaramida SA, et al. Comparison of dual-energy computed tomography of the heart with single photon emission computed tomography for assessment of coronary artery stenosis and of the myocardial blood supply. Am J Cardiol 2009;104:318-26.PubMedCrossRef Ruzsics B, Schwarz F, Schoepf UJ, Lee YS, Bastarrika G, Chiaramida SA, et al. Comparison of dual-energy computed tomography of the heart with single photon emission computed tomography for assessment of coronary artery stenosis and of the myocardial blood supply. Am J Cardiol 2009;104:318-26.PubMedCrossRef
12.
Zurück zum Zitat Mor-Avi V, Lodato JA, Kachenoura N, Chandra S, Freed BH, Newby B, et al. Quantitative three-dimensional evaluation of myocardial perfusion during regadenoson stress using multidetector computed tomography. Journal of computer assisted tomography 2012;36:443-9.PubMedCrossRef Mor-Avi V, Lodato JA, Kachenoura N, Chandra S, Freed BH, Newby B, et al. Quantitative three-dimensional evaluation of myocardial perfusion during regadenoson stress using multidetector computed tomography. Journal of computer assisted tomography 2012;36:443-9.PubMedCrossRef
13.
Zurück zum Zitat Patel AR, Lodato JA, Chandra S, Kachenoura N, Ahmad H, Freed BH, et al. Detection of myocardial perfusion abnormalities using ultra-low radiation dose regadenoson stress multidetector computed tomography. J Cardiovasc Comput Tomogr 2011;5:247-54.PubMedCrossRef Patel AR, Lodato JA, Chandra S, Kachenoura N, Ahmad H, Freed BH, et al. Detection of myocardial perfusion abnormalities using ultra-low radiation dose regadenoson stress multidetector computed tomography. J Cardiovasc Comput Tomogr 2011;5:247-54.PubMedCrossRef
14.
Zurück zum Zitat Thomas GS, Tammelin BR, Schiffman GL, Marquez R, Rice DL, Milikien D, et al. Safety of regadenoson, a selective adenosine A2A agonist, in patients with chronic obstructive pulmonary disease: A randomized, double-blind, placebo-controlled trial (RegCOPD trial). J Nucl Cardiol 2008;15:319-28.PubMedCrossRef Thomas GS, Tammelin BR, Schiffman GL, Marquez R, Rice DL, Milikien D, et al. Safety of regadenoson, a selective adenosine A2A agonist, in patients with chronic obstructive pulmonary disease: A randomized, double-blind, placebo-controlled trial (RegCOPD trial). J Nucl Cardiol 2008;15:319-28.PubMedCrossRef
15.
Zurück zum Zitat Zhao G, Zhang S, Shryock JC, Xu X, Ochoa M, Hintze TH, et al. Selective action of metoprolol to attenuate regadenoson-induced tachycardia in conscious dogs. J Nucl Cardiol 2012;19:109-17.PubMedCrossRef Zhao G, Zhang S, Shryock JC, Xu X, Ochoa M, Hintze TH, et al. Selective action of metoprolol to attenuate regadenoson-induced tachycardia in conscious dogs. J Nucl Cardiol 2012;19:109-17.PubMedCrossRef
16.
Zurück zum Zitat Blankstein R, Shturman LD, Rogers IS, Rocha-Filho JA, Okada DR, Sarwar A, et al. Adenosine-induced stress myocardial perfusion imaging using dual-source cardiac computed tomography. J Am Coll Cardiol 2009;54:1072-84.PubMedCrossRef Blankstein R, Shturman LD, Rogers IS, Rocha-Filho JA, Okada DR, Sarwar A, et al. Adenosine-induced stress myocardial perfusion imaging using dual-source cardiac computed tomography. J Am Coll Cardiol 2009;54:1072-84.PubMedCrossRef
17.
Zurück zum Zitat Feuchtner G, Goetti R, Plass A, Wieser M, Scheffel H, Wyss C, et al. Adenosine stress high-pitch 128-slice dual-source myocardial computed tomography perfusion for imaging of reversible myocardial ischemia: Comparison with magnetic resonance imaging. Circ Cardiovasc Imaging 2011;4:540-9.PubMedCrossRef Feuchtner G, Goetti R, Plass A, Wieser M, Scheffel H, Wyss C, et al. Adenosine stress high-pitch 128-slice dual-source myocardial computed tomography perfusion for imaging of reversible myocardial ischemia: Comparison with magnetic resonance imaging. Circ Cardiovasc Imaging 2011;4:540-9.PubMedCrossRef
18.
Zurück zum Zitat Bamberg F, Becker A, Schwarz F, Marcus RP, Greif M, von Ziegler F, et al. Detection of hemodynamically significant coronary artery stenosis: Incremental diagnostic value of dynamic CT-based myocardial perfusion imaging. Radiology 2011;260:689-98.PubMedCrossRef Bamberg F, Becker A, Schwarz F, Marcus RP, Greif M, von Ziegler F, et al. Detection of hemodynamically significant coronary artery stenosis: Incremental diagnostic value of dynamic CT-based myocardial perfusion imaging. Radiology 2011;260:689-98.PubMedCrossRef
19.
Zurück zum Zitat Kurata A, Mochizuki T, Koyama Y, Haraikawa T, Suzuki J, Shigematsu Y, et al. Myocardial perfusion imaging using adenosine triphosphate stress multi-slice spiral computed tomography: Alternative to stress myocardial perfusion scintigraphy. Circ J 2005;69:550-7.PubMedCrossRef Kurata A, Mochizuki T, Koyama Y, Haraikawa T, Suzuki J, Shigematsu Y, et al. Myocardial perfusion imaging using adenosine triphosphate stress multi-slice spiral computed tomography: Alternative to stress myocardial perfusion scintigraphy. Circ J 2005;69:550-7.PubMedCrossRef
20.
Zurück zum Zitat Ko SM, Choi JW, Hwang HK, Song MG, Shin JK, Chee HK. Diagnostic performance of combined noninvasive anatomic and functional assessment with dual-source CT and adenosine-induced stress dual-energy CT for detection of significant coronary stenosis. AJR Am J Roentgenol 2012;198:512-20.PubMedCrossRef Ko SM, Choi JW, Hwang HK, Song MG, Shin JK, Chee HK. Diagnostic performance of combined noninvasive anatomic and functional assessment with dual-source CT and adenosine-induced stress dual-energy CT for detection of significant coronary stenosis. AJR Am J Roentgenol 2012;198:512-20.PubMedCrossRef
21.
Zurück zum Zitat Cury RC, Magalhaes TA, Borges AC, Shiozaki AA, Lemos PA, Junior JS, et al. Dipyridamole stress and rest myocardial perfusion by 64-detector row computed tomography in patients with suspected coronary artery disease. Am J Cardiol 2010;106:310-5.PubMedCrossRef Cury RC, Magalhaes TA, Borges AC, Shiozaki AA, Lemos PA, Junior JS, et al. Dipyridamole stress and rest myocardial perfusion by 64-detector row computed tomography in patients with suspected coronary artery disease. Am J Cardiol 2010;106:310-5.PubMedCrossRef
22.
Zurück zum Zitat Okada DR, Ghoshhajra BB, Blankstein R, Rocha-Filho JA, Shturman LD, Rogers IS, et al. Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT. J Nucl Cardiology 2010;17:27-37.CrossRef Okada DR, Ghoshhajra BB, Blankstein R, Rocha-Filho JA, Shturman LD, Rogers IS, et al. Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT. J Nucl Cardiology 2010;17:27-37.CrossRef
23.
Zurück zum Zitat Tamarappoo BK, Dey D, Nakazato R, Shmilovich H, Smith T, Cheng VY, et al. Comparison of the extent and severity of myocardial perfusion defects measured by CT coronary angiography and SPECT myocardial perfusion imaging. JACC Cardiovasc Imaging 2010;3:1010-9.PubMedCrossRef Tamarappoo BK, Dey D, Nakazato R, Shmilovich H, Smith T, Cheng VY, et al. Comparison of the extent and severity of myocardial perfusion defects measured by CT coronary angiography and SPECT myocardial perfusion imaging. JACC Cardiovasc Imaging 2010;3:1010-9.PubMedCrossRef
24.
Zurück zum Zitat Ho KT, Chua KC, Klotz E, Panknin C. Stress and rest dynamic myocardial perfusion imaging by evaluation of complete time-attenuation curves with dual-source CT. JACC Cardiovasc Imaging 2010;3:811-20.PubMedCrossRef Ho KT, Chua KC, Klotz E, Panknin C. Stress and rest dynamic myocardial perfusion imaging by evaluation of complete time-attenuation curves with dual-source CT. JACC Cardiovasc Imaging 2010;3:811-20.PubMedCrossRef
25.
Zurück zum Zitat George RT, Arbab-Zadeh A, Miller JM, Vavere AL, Bengel FM, Lardo AC, et al. Computed tomography myocardial perfusion imaging with 320-row detector computed tomography accurately detects myocardial ischemia in patients with obstructive coronary artery disease. Circ Cardiovasc Imaging 2012;5:333-40.PubMedCrossRef George RT, Arbab-Zadeh A, Miller JM, Vavere AL, Bengel FM, Lardo AC, et al. Computed tomography myocardial perfusion imaging with 320-row detector computed tomography accurately detects myocardial ischemia in patients with obstructive coronary artery disease. Circ Cardiovasc Imaging 2012;5:333-40.PubMedCrossRef
26.
Zurück zum Zitat Feuchtner GM, Plank F, Pena C, Battle J, Min J, Leipsic J, et al. Evaluation of myocardial CT perfusion in patients presenting with acute chest pain to the emergency department: Comparison with SPECT-myocardial perfusion imaging. Heart 2012;98:1510-7.PubMedCrossRef Feuchtner GM, Plank F, Pena C, Battle J, Min J, Leipsic J, et al. Evaluation of myocardial CT perfusion in patients presenting with acute chest pain to the emergency department: Comparison with SPECT-myocardial perfusion imaging. Heart 2012;98:1510-7.PubMedCrossRef
27.
Zurück zum Zitat Weininger M, Schoepf UJ, Ramachandra A, Fink C, Rowe GW, Costello P, et al. Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results. Eur J Radiol 2012;81:3703-10.PubMedCrossRef Weininger M, Schoepf UJ, Ramachandra A, Fink C, Rowe GW, Costello P, et al. Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results. Eur J Radiol 2012;81:3703-10.PubMedCrossRef
28.
Zurück zum Zitat Ko SM, Choi JW, Song MG, Shin JK, Chee HK, Chung HW, et al. Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: Comparison with cardiac magnetic resonance imaging and conventional coronary angiography. Eur Radiol 2011;21:26-35.PubMedCrossRef Ko SM, Choi JW, Song MG, Shin JK, Chee HK, Chung HW, et al. Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: Comparison with cardiac magnetic resonance imaging and conventional coronary angiography. Eur Radiol 2011;21:26-35.PubMedCrossRef
29.
Zurück zum Zitat Ko BS, Cameron JD, Meredith IT, Leung M, Antonis PR, Nasis A, et al. Computed tomography stress myocardial perfusion imaging in patients considered for revascularization: A comparison with fractional flow reserve. Eur Heart J 2012;33:67-77.PubMedCrossRef Ko BS, Cameron JD, Meredith IT, Leung M, Antonis PR, Nasis A, et al. Computed tomography stress myocardial perfusion imaging in patients considered for revascularization: A comparison with fractional flow reserve. Eur Heart J 2012;33:67-77.PubMedCrossRef
30.
Zurück zum Zitat George RT, Arbab-Zadeh A, Cerci RJ, Vavere AL, Kitagawa K, Dewey M, et al. Diagnostic performance of combined noninvasive coronary angiography and myocardial perfusion imaging using 320-MDCT: The CT angiography and perfusion methods of the CORE320 multicenter multinational diagnostic study. AJR Am J Roentgenol 2011;197:829-37.PubMedCrossRef George RT, Arbab-Zadeh A, Cerci RJ, Vavere AL, Kitagawa K, Dewey M, et al. Diagnostic performance of combined noninvasive coronary angiography and myocardial perfusion imaging using 320-MDCT: The CT angiography and perfusion methods of the CORE320 multicenter multinational diagnostic study. AJR Am J Roentgenol 2011;197:829-37.PubMedCrossRef
31.
Zurück zum Zitat Shaw LJ, Hendel RC, Heller GV, Borges-Neto S, Cerqueira M, Berman DS. Prognostic estimation of coronary artery disease risk with resting perfusion abnormalities and stress ischemia on myocardial perfusion SPECT. J Nucl Cardiol 2008;15:762-73.PubMed Shaw LJ, Hendel RC, Heller GV, Borges-Neto S, Cerqueira M, Berman DS. Prognostic estimation of coronary artery disease risk with resting perfusion abnormalities and stress ischemia on myocardial perfusion SPECT. J Nucl Cardiol 2008;15:762-73.PubMed
32.
Zurück zum Zitat Zemrak F, Petersen SE. Late gadolinium enhancement CMR predicts adverse cardiovascular outcomes and mortality in patients with coronary artery disease: Systematic review and meta-analysis. Prog Cardiovasc Dis 2011;54:215-29.PubMedCrossRef Zemrak F, Petersen SE. Late gadolinium enhancement CMR predicts adverse cardiovascular outcomes and mortality in patients with coronary artery disease: Systematic review and meta-analysis. Prog Cardiovasc Dis 2011;54:215-29.PubMedCrossRef
Metadaten
Titel
CT imaging of myocardial perfusion: Possibilities and perspectives
verfasst von
Alexander Becker, MD
Christoph Becker, MD
Publikationsdatum
01.04.2013
Verlag
Springer US
Erschienen in
Journal of Nuclear Cardiology / Ausgabe 2/2013
Print ISSN: 1071-3581
Elektronische ISSN: 1532-6551
DOI
https://doi.org/10.1007/s12350-013-9681-7

Weitere Artikel der Ausgabe 2/2013

Journal of Nuclear Cardiology 2/2013 Zur Ausgabe

Journal of Nuclear Cardiology News Update

Nuclear Cardiology: Call to Action

ASNC 2013 Education Calendar

ASNC 2013 Education Calendar

Screening-Mammografie offenbart erhöhtes Herz-Kreislauf-Risiko

26.04.2024 Mammografie Nachrichten

Routinemäßige Mammografien helfen, Brustkrebs frühzeitig zu erkennen. Anhand der Röntgenuntersuchung lassen sich aber auch kardiovaskuläre Risikopatientinnen identifizieren. Als zuverlässiger Anhaltspunkt gilt die Verkalkung der Brustarterien.

Niedriger diastolischer Blutdruck erhöht Risiko für schwere kardiovaskuläre Komplikationen

25.04.2024 Hypotonie Nachrichten

Wenn unter einer medikamentösen Hochdrucktherapie der diastolische Blutdruck in den Keller geht, steigt das Risiko für schwere kardiovaskuläre Ereignisse: Darauf deutet eine Sekundäranalyse der SPRINT-Studie hin.

Therapiestart mit Blutdrucksenkern erhöht Frakturrisiko

25.04.2024 Hypertonie Nachrichten

Beginnen ältere Männer im Pflegeheim eine Antihypertensiva-Therapie, dann ist die Frakturrate in den folgenden 30 Tagen mehr als verdoppelt. Besonders häufig stürzen Demenzkranke und Männer, die erstmals Blutdrucksenker nehmen. Dafür spricht eine Analyse unter US-Veteranen.

Adipositas-Medikament auch gegen Schlafapnoe wirksam

24.04.2024 Adipositas Nachrichten

Der als Antidiabetikum sowie zum Gewichtsmanagement zugelassene Wirkstoff Tirzepatid hat in Studien bei adipösen Patienten auch schlafbezogene Atmungsstörungen deutlich reduziert, informiert der Hersteller in einer Vorab-Meldung zum Studienausgang.

Update Kardiologie

Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert.