Abstract Purpose: To compare the radiation doses and image qualities of computed tomography (CT)-guided interventions using a standard-dose CT (SDCT) protocol with filtered back projection and a low-dose CT (LDCT) protocol with both filtered back projection and iterative reconstruction. Materials and Methods: Image quality and radiation doses (dose-length product and CT dose index) were retrospectively reviewed for 130 patients who underwent CT-guided lung interventions. SDCT at 120 kVp and automatic mA modulation and LDCT at 100 kVp and a fixed exposure were each performed for 65 patients. Image quality was objectively evaluated as the contrast-to-noise ratio and subjectively by two radiologists for noise impression, sharpness, artifacts and diagnostic acceptability on a four-point scale. Results: The groups did not significantly differ in terms of diagnostic acceptability and complication rate. LDCT yielded a median 68.6 % reduction in the radiation dose relative to SDCT. In the LDCT group, iterative reconstruction was superior to filtered back projection in terms of noise reduction and subjective image quality. The groups did not differ in terms of beam hardening artifacts. Conclusion: LDCT was feasible for all procedures and yielded a more than two-thirds reduction in radiation exposure while maintaining overall diagnostic acceptability, safety and precision. The iterative reconstruction algorithm is preferable according to the objective and subjective image quality analyses. Key Points: • Implementation of a low-dose computed tomography (LDCT) protocol for lung interventions is feasible and safe. • LDCT protocols yield a significant reduction (more than 2/3) in radiation exposure. • Iterative reconstruction algorithms considerably improve the image quality in LDCT protocols. Citation Format: • Chang DH, Hiss S, Mueller D et al. Radiation Dose Reduction in Computed Tomography-Guided Lung Interventions using an Iterative Reconstruction Technique. Fortschr Röntgenstr 2015; 187: 906 – 914

Poland's syndrome is a rare congenital entity characterized by unilateral partial or total hypoplasia of the major pectoralis muscle, breast and/or ipsilateral hand abnormalities. It has been reported in association with various structural and functional abnormalities. We report about a 23-year-old male kick-boxer with Poland's syndrome who presented in our department the history of two traumatic anterior shoulder dislocations due to boxing and self-reductions. Physical examination showed an instability of the left shoulder, and the MRI scans demonstrated a Bankart lesion. The patient had been treated with an arthroscopic Bankart repair; reattachment of the detached antero-inferior labrum down to the glenoid and repairing of the inferior gleno-humeral ligament complex. To our knowledge this is a first case report of a patient presenting with traumatic anterior shoulder dislocations due to kick-boxing associated with Poland's syndrome.

1) to evaluate the feasibility and accuracy of standard GRE and myocardial tagging for detection of obstructive CAD in a high dose dobutamine stress protocol and

Ziele: Evaluierung eines Cine-Gradientenecho (Cine-GRE)/Tagging Protokolls im Rahmen eines Hochdosis-Dobutamin-Stress-Protokolls bei 3T bei Patienten mit V.a. eine obstruktive KHK. Methode: 33 Patienten mit Verdacht auf eine KHK wurden an einem 3T-System mittels eines Hochdosis-Dobutamin-Stress-Protokolls bis zum Erreichen der Zielherzfrequenz bzw. bis zum Auftreten stressinduzierter Wandbewegunsstörungen (WBS) belastet. Es wurden jeweils 4 identische Kurzachsenschnitte der Cine-GRE und Tagging Sequenzen (Cine-GRE TR/TE/a: 4,8ms, 2,6ms, 20°, 25 Herzphasen; Tagging TR/TE/a: 3,7ms, 2,2ms, 10°, 16 Herzphasen, 8mm Tag Abstand) in Ruhe und auf jeder Stressstufe akquiriert. Die Bildqualität wurde bei der höchsten Belastungsstufe für beide Sequenzen auf einer 5-Punkte-Skala beurteilt (1: exzellent; 5: nicht-diagnostisch). Die Sequenzen wurden im Hinblick auf stressinduzierte neu aufgetretene bzw. sich verschlechternde WBS als Hinweis auf eine hämodynamisch relevante KHK (Goldstandard: Diameterstenose ≥70% in der konventionellen Katheter-Koronarangiographie) analysiert Ergebnis: Die Untersuchung konnte bei allen Patienten (n=33/33) komplikationslos beendet werden. Die durchschnittliche Bildqualität betrug 2,2 für das Tagging und 2,4 für die Cine-GRE Untersuchungen. Alle Cine-GRE Untersuchungen (n=33) und Tagging Untersuchungen (n=33) ergaben eine diagnostische Bildqualität. Die Sensitivität/Spezifität in der Detektion einer obstruktiven KHK betrugen 93%/79% für das myokardiale Tagging und 79%/84% für die Cine-GRE Untersuchung. Die Tagging Untersuchungen wiesen einen falsch negativen Befund auf, die Cine-GRE Untersuchungen drei. Die Analyse von 11 sowohl im Tagging als auch in der Cine-GRE Sequenzen richtig positiv befundeten Fälle zeigte bei 4 Patienten (n=4/11) eine Detektion der WBS auf einer niedrigeren Dobutamin Belastungsstufe in der Tagging Untersuchung im Vergleich zur Cine-GRE Untersuchung. Schlussfolgerung: 1. Die Kombination einer Cine-GRE Untersuchung mit myokardialem Tagging bei 3T im Rahmen eines Hochdosis-Dobutamin-Atropin-Protokolls ist ein klinisch praktikables Verfahren mit konsistent guter Bildqualität.

From the results obtained we conclude that standardized radiograms in two planes were able to demonstrate the full extent of the basic lesion and thereby to facilitate planning of accurate therapy. Operative fixation of low grade dislocation as inaugurated by Imhäuser and intertrochanteric corrective osteotomy of higher grade dislocations, respectively, have been proved useful as well; whether or not the critical angle is to be assumed at 30 degrees cannot be proved by our material and won't be able to be proved until our own longstanding epicritical observations are available as well as the results of patients treated by different regimens. Based on our experiences with patients treated at other places we believe in operative fixation of the "healthy" contralateral hip in accordance with Imhäuser. This statement can be made as a result of our experiences with 83 patients suffering from chronic dislocation of the upper femoral epiphysis. In future it appears desirable to concentrate on the problem of primary chondrolysis because chondrolysis as well as the remaining residual deformity after treatment appears to be decisive for the fate of the joint.

We report about an unusual case of a rupture of the Achilles tendon ina patient with Haglund's exostosis and long term achillodynia. Intraoperatively, we found a fresh superficial typically located tendon-rupture and an old deep round shaped rupture which was located directly over the cranial edge of the calcaneous bone spur.We presume that the sharp edge of Haglund's deformity was the cause of the deep tendon rupture, because the location of the round shaped rupture was near the exostosis. The additional superficial rupture, caused by an inadequate trauma, induced operative revision consisting of double layer transosseous suturing.In conclusion early operative resection of Haglund's deformity in cases of repeated irritations of the Achilles tendon should be performed to avoid mechanical damage, including the risk of rupture by the hypomochlion-like effect of the exostosis.

Purpose: While adenosine-stress perfusion imaging is a very sensitive technique for the detection of coronary artery disease (CAD), its specificity is rather low. In contrary the use of standard adenosine-stress cine imaging lacks high sensitivity, but is very specific for detection of CAD. Detection of wall motion abnormalities (WMAs) can be improved by the use of myocardial tagging techniques. Both, myocardial perfusion imaging and myocardial tagging benefit from high field strength due to increased CNR, SNR as well as improved tag persistence and tag definition, allowing for high image resolution and combination with parallel imaging techniques. Thus, the aim of the study was:

Ziele: Die kurzfristigen und langfristigen Effekte von Transjugulären Intrahepatischen Shunts (TIPS) auf die kardiale Funktion von Patienten mit Leberzirrhose zu ermitteln. Methode: 11 Patienten mit Ösophagusvarizen und refraktärer Aszites wurden bei 1,5T (Intera, Philips Medical Systems, Hamburg) jeweils vor, 24h nach und 3 bis 6 Monate nach TIPS-Anlage untersucht. Zusätzlich erfolgte eine invasive Druckmessung während der TIPS-Implantation. Ein kontinuierlicher Schichtstapel einer balanced-FFE Sequenz von der Herzbasis bis zur Herzspitze (TR/TE/FA 3,3ms/1,6ms/60°) und Phasenkontrastmessungen über alle Herzklappen (TR/TE/FA 6,1ms/2,9ms/18°) wurden akquiriert. Die Bilddaten wurden anhand der Zeitverlaufskurven und ihrer ersten Ableitungen (MASS and Flow, Medis, Niederlande) ausgewertet. Ergebnis: Der portoatriale Druckgradient sank mit TIPS-Insertion von 19,8 +/- 2,3 auf 6,6 +/- 2,3mm Hg. Der zentrale Venendruck, der mittlere pulmonalarterielle Druck und der pulmonale Wedge-Druck zeigten unmittelbar nach TIPS-Implantation eine signifikante Zunahme (jeweils um 66%, 86% und 112%). Die rechtsventrikulären und die linksventrikulären enddiastolischen Volumina waren nach TIPS-Implantation initial merklich erhöht (11% and 13%, p < 0.001), fielen aber nach 3 Monaten auf ihre Ausgangswerte zurück. Die Schlagvolumina waren initial um 23% erhöht und blieben im Verlauf leicht erhöht (11%, p=0,026). Im langfristigen Verlauf nahm die linksventrikuläre Myokardmasse in allen Patienten im Durchschnitt um 7,9g (p<0,001). Schlussfolgerung: Die erhöhte Volumenbelastung des Herzens nach TIPS-Implantation führte entsprechend der erhöhten Vorlast vorübergehend zur Volumenzunahme der Herzhöhlen mit Zeichen einer restriktiven Störung der diastolischen Füllung. Eine Normalisierung dieser initialen Veränderungen stellte sich nach 3–6 Monaten begleitend zu einem Umbau des linksventrikulären Myokards ein.

Ziele: Evaluierung einer Kombination von B-SSFP-Sequenzen und paralleler Bildgebungstechnik bei Dobutamin-Stress-MRT-Untersuchungen des Herzens in der Primärdiagnostik der KHK. Methode: 38 Patienten mit V.a. eine KHK wurden an einem 1,5 T-System (Gyroscan Intera, Philips) unter Anwendung eines Hochdosis-Dobutamin-Atropin-Protokolls im Hinblick auf stressinduzierte Wandbewegungsstörungen (WBS) untersucht. Es wurden retrospektiv getriggerte B-SSFP-Sequenzen unter Anwendung paralleler Bildgebung (SENSE) akquiriert (Sensefaktor 2; zwei Schichten/breathhold; Flipwinkel 50°; TR/TE 3,3/1,63 ms; Voxelgröße 1,37×1,36×8,0 mm3; 30 Phasen/RR-Intervall). In Ruhe und auf jeder Dobutamin-Belastungsstufe (10, 20, 30, 40µg/kg/KG/min) wurden jeweils zwei Schichten im Vierkammerblick zur Abdeckung der Herzspitze sowie vier Kurzachsenschnitte angefertigt, entsprechend einer Gesamtzahl von jeweils 3 Atemanhaltemanövern in Ruhe und bei jeder Belastungsstufe. Die Bildqualität wurde bei der höchsten Belastungsstufe auf einer 4-Punkte-Skala beurteilt: [Grad 1: scharfe Abgrenzung der endokardialen Grenzen des Myokards in allen Segmenten; Grad 4 endokardiale Grenzen des Myokards nicht abgrenzbar in ≥4/17 Segmenten (nicht diagnostisch)]. Nach jeder Belastungsstufe wurden die MRT-Bilder unmittelbar nach Akquisition im Hinblick auf neu aufgetretene WBS als Hinweis auf eine hämodynamisch relevante KHK (Goldstandard: ≥50%-ige Diameterstenose in der konventionellen Katheter-Koronarangiographie) analysiert. Ergebnis: Die Untersuchung konnte bei allen Patienten (n=38/38) komplikationslos durchgeführt werden. Die Bildqualität entsprach Grad 1 bei 31,6% (12/38 Patienten), Grad 2 bei 47,4% (18/38), Grad 3 bei 21% (8/38) und Grad 4 bei 0% (0/38). Sensitivität, Spezifität und Testgenauigkeit im Nachweis einer hämodynamisch signifikanten KHK betrugen 84,2%, 89,5% und 86,8%. Schlussfolgerung: Die Kombination von B-SSFP-Sequenzen und SENSE im Rahmen eines Hochdosis-Dobutamin-Atropin-Protokolls ist ein klinisch praktikables Verfahren mit konsistent guter Bildqualität und hoher Sensitivität und Spezifität in der Detektion einer hämodynamisch signifikanten KHK. Die Anwendung von SENSE ermöglicht die Reduktion der notwendigen Anzahl von Atemanhaltemanövern um 50%, erhöht dadurch die Patientencompliance, verkürzt die Dobutamin-Belastungszeit und verbessert das Sicherheitsprofil kardialer Dobutamin-Belastungsuntersuchungen.

Background-The purpose of the present study was to evaluate a strategy for safe performance of extrathoracic magnetic resonance imaging (MRI) in non-pacemaker-dependent patients with cardiac pacemakers.Methods and Results-Inclusion criteria were presence of a cardiac pacemaker and urgent clinical need for an MRI examination. Pacemaker-dependent patients and those requiring examinations of the thoracic region were excluded. The study group consisted of 82 pacemaker patients who underwent a total of 115 MRI examinations at 1.5T. To minimize radiofrequency-related lead heating, the specific absorption rate was limited to 1.5 W/kg. All pacemakers were reprogrammed before MRI: If heart rate was < 60 bpm, the asynchronous mode was programmed to avoid magnetic resonance (MR)-induced inhibition; if heart rate was > 60 bpm, sense-only mode was used to avoid MR-induced competitive pacing and potential proarrhythmia. Patients were monitored with ECG and pulse oximetry. All pacemakers were interrogated immediately before and after the MRI examination and after 3 months, including measurement of pacing capture threshold (PCT) and serum troponin I levels. All MR examinations were completed safely. Inhibition of pacemaker output or induction of arrhythmias was not observed. PCT increased significantly from pre- to post-MRI (P = 0.017). In 2 of 195 leads, an increase in PCT was only detected at follow-up. In 4 of 114 examinations, troponin increased from a normal baseline value to above normal after MRI, and in 1 case (troponin pre-MRI 0.02 ng/mL, post-MRI 0.16 ng/mL), this increase was associated with a significant increase in PCT.Conclusions-Extrathoracic MRI of non-pacemaker-dependent patients can be performed with an acceptable risk-benefit ratio under controlled conditions and by taking both MR-and pacemaker-related precautions.

Introduction: Cerebral embolism and stroke are feared complications of left atrial catheter ablation such as pulmonary vein (PV) ablation. In order to assess the thrombogenicity of left atrial catheter ablation, knowledge of both clinically evident as well as silent cerebral embolism is important. The aim of the current study was to examine the use of diffusion‐weighted magnetic resonance imaging (DW‐MRI) for detection of cerebral embolism, apparent as well as silent, caused by PV catheter ablation. Methods and Results: Twenty consecutive patients without structural heart disease undergoing lasso catheter‐guided ostial PV ablation using an irrigated‐tip ablation catheter were studied. Cerebral MRI including DW single‐shot spin echo echoplanar, turbo fluid attenuated inversion recovery, and T2‐weighted turbo spin echo sequences were performed the day after the ablation procedure. Ten patients also underwent preprocedure cerebral MRI. All ablation procedures were performed without acute complications. A mean of 3.2 ± 0.6 PVs were ablated per patient. No patient had neurological symptoms following the procedure. In 2 of 20 patients (10%), DW‐MRI revealed new embolic lesions, which were located in the right periventricular white matter in one and in the left temporal lobe in the other patient. There was no statistically significant difference in age, history of hypertension, left atrial volume, and procedure duration between the 2 patients with and the 18 patients without cerebral embolism following AF ablation. Conclusion: This is the first study using highly sensitive DW‐MRI of the brain to detect asymptomatic cerebral embolism after left atrial catheter ablation. Even small, clinically silent, embolic lesions can be demonstrated with this technique. DW‐MRI can be used to monitor and compare the thrombogenicity of different AF ablation approaches.

Ziele: Bei der kardialen Vitalitätsdiagnostik ermöglicht der 3D Inversion recovery (IR) Ansatz die komplette Darstellung des linken Ventrikels (LV) in der kurzen Achse in 2 Atemanhaltemanövern. Der Hauptnachteil dieses Ansatzes bei 1,5 T im Vergleich zur standard 2D Technik, mit multiplen (8–10) Atemanhaltemanövern zur Darstellung des LV Myokards, ist die geringere räumliche Auflösung. Die Bildgebung bei 3 Tesla ermöglicht aufgrund des höheren Signal-zu-Rausch Verhältnisses eine Erhöhung der Ortsauflösung. Ziel dieser Studie war die Evaluierung einer hochauflösenden 3D IR „late enhancement“ Sequenz bei 3 Tesla im Vergleich zum standard 2D Ansatz in der Darstellung myokardialer Infarkte. Methode: Bei 38 Pat. mit bekanntem oder vermutetem Myokardinfarkt (MI) wurde eine Vitalitätsdiagnostik durchgeführt (Achieva 3 T, Philips). Für den Standardansatz wurde eine 2D IR Gradientenechosequenz (Auflösung 1,4×1,6×8mm3) mit 10 Atemanhaltemanövern durchgeführt (Dauer 146s), um den gesamten LV in kurzer Achse abzudecken. Der 3D Ansatz bestand aus einer k-Raum segmentierten 3D IR Sequenz mit identischer räumlicher Auflösung mit Abdeckung des gesamten LV in nur 2 Atemmanövern (Dauer 29s). Die Bildakquisition erfolgte 10 bis 30min nach i.v. Injektion von 0,2 mmol/kg Gd-DTPA. Bei beiden Verfahren wurde 1. die Inzidenz myocardialer Infarkte, 2. das Infarktvolumen, 3. die transmurale Ausdehnung (1: 0–25%,2: 25–50%, 3: 50–75%, 4: 75–100%), 4. die Bildqualität auf einer 5-Punkte Skala und 5. der Kontrast Infarkt/vitales Myokard bestimmt. Ergebnis: Es ergaben sich im Vergleich zwischen der hochauflösenden 3D Sequenz und dem Standard 2D Ansatz keine signifikanten Unterschiede bzgl. der Inzidenz myocardialer Infarkte (28/38 vs. 28/38), dem Infarktvolumen (42,1g +/- 23,7g vs. 41,4g +/- 24,5g), der transmuralen Infarktausdehnung (2,4 +/- 1,4 vs. 2,3 +/- 1,3) und dem Kontrast (0,85 vs. 0,82). Die Evaluierung der Bildqualität ergab einen Trend, aber keinen signifikanten Unterschied zwischen den beiden Sequenzen (4,33 vs. 4,12). Schlussfolgerung: Die 3T Bildgebung ermöglicht die Durchführung einer hochauflösenden 3D IR Sequenz zur Darstellung myokardialer Infarkte in nur 2 Atemanhaltemanövern. Dieses Verfahren ist bezüglich der diagnostischen Genauigkeit (Infarktnachweis, Infarktvolumen, transmurale Infarktausdehnung) dem Standard 2D Ansatz gleichwertig und erreicht eine mindestens äquivalente Bildqualität bei gleichzeitig deutlich reduzierter Untersuchungsdauer.

Ziele: Evaluierung 1) einer hochauflösenden Ruhe-Myokardperfusion bei Probanden (Gruppe 1) bei 3T im Vergleich zu einem Standardansatz bei 1,5T sowie 2) der technischen Durchführbarkeit und diagnostischen Genauigkeit hochauflösender Stress-Rest-Myokardperfusionsstudien bei Patienten mit V.a. koronare Herzerkrankung (KHK) (Gruppe 2) bei 3T. Methode: Alle Perfusionsuntersuchungen (Gd-DTPA 0,05 mmol/kg KG) erfolgten mit einer T1-gewichteten k-Raum segmentierten Gradienten-Echo-Sequenz in Kombination mit paralleler Bildgebung.

Purpose: Recently, myocardial rest perfusion in healthy volunteers at 3.0T has been shown to significantly increase signal-to-noise-ratio (SNR) in comparison to 1.5T. However, the benefits of 3.0T with respect to image quality in comparison to 1.5T as well as diagnostic accuracy for the detection of coronary artery disease (CAD) have not been evaluated, yet.

Diffusion-weighted magnetic resonance imaging (DW-MRI) has shown to be highly sensitive for detection of acute ischemic lesions associated with catheter based interventions. Aim of this study was to examine the incidence of clinically silent cerebral embolism 2nd to segmental ostial pulmonary vein (PV) ablation in a large group of patients (pt).

Introduction: Myocardial viability assessment is crucial in prognostic stratification and therapeutic decision making for patients after acute myocardial infarction. MRI has shown high capability in viability assessment, also compared to current clinical tools. Purpose: To define contrast enhanced (CE) MRI role in functional recovery prediction after acute myocardial infarction. Methods: 43 consecutive patients with first AMI (64 ± 9 yrs., 36 anterior, 7 inferior, 37 primary PTCA, 6 thrombolysis) underwent cineand CE-MRI (GE Signa Horizon Echospeed; GE Signa LX Excite) within fifth day after onset. Cine-MRI was performed in short axis (6–8 slices, Fastcard and FIESTA sequences); first pass imaging (IR-prep FGRE and FGRE-ET with iv 0.1 mmol/kg Gd-DTPA, 3 mL/s) was obtained on three short axis slices (basal, mid-ventricular and apical); multi-slice short axis (6 slices) delayed T1 imaging (IR-prep FGRE) was obtained 20 min after Gd injection. A total amount of 731 segments were classified as: 1) normal first-pass, absent or delayed hyperenhancement; 2) hypoenhancement at first-pass, delayed hyperenhancement; 3) hypoenhancement both at first-pass and delayed imaging. Segments out of first-pass slices (total amount 774) were classified at delayed imaging as normal (= type 1), hyperenhanced (= type 2) and hypoenhanced (= type 3). Patterns 2 and 3 were considered non viable. At six months MRI assessed functional recovery. Results: Pattern 1 was observed in 1262 segments, with functional recovery appreciated in 1195 (94.7%). Pattern 3 was present in only 31 segments, without recovery (100%). Pattern 2 was observed in 212 segments: out of them, 39 showed recovery (18%). Conclusions: Patterns 1 and 3 respectively identify viable and non viable tissue. Pattern 2 is less specific early after AMI, as it may represent also viable myocardium and should be carefully interpreted.

Ziel: Methode: Ergebnisse: Schlussfolgerung: Purpose: Materials and Methods: Results: Conclusion:

PURPOSE Patients (pts.) with atrial fibrillation (AF) and atrial thrombi are known to have an increased risk for cerebral embolism. However, little is known about the clinical course of atrial thrombi and the incidence of cerebral embolism in those patients during anticoagulation therapy. The high sensitivity of MR imaging (MRI) including diffusion-weighted imaging (DWI) suggests that this technique could provide an improved estimate of cerebral embolism associated with the presence of left atrial thrombi. The aims of this prospective study were to evaluate 1) the prevalence of clinically silent and apparent cerebral embolism in pts. with newly diagnosed AF and atrial thrombi using MRI/DWI, 2) the long-term fate of atrial thrombi under continues anticoagulation therapy and 3) the incidence of cerebral embolism during a follow-up period of 12 months with continuous anticoagulation therapy. MATERIALS AND METHODS The study group consisted of 32 pts. with 1) newly diagnosed AF and evidence of left atrial (LA) thrombi detected by TEE and 2) a new start of anticoagulation therapy [International Normalized Ratio (INR) 2.0 - 3.0]. 19 pts. with 1) newly diagnosed AF and no evidence of atrial thrombi and 2) an equivalent anticoagulation regimen served as the control group. In both groups a) MRI/DWI studies of the brain (weeks 0, 4, 8, 12, 20, 28, 36, 44, and 52), b) transesophageal echocardiographic studies (TEE) for assessment of LA-Thrombi (weeks 0 and 52) and c) clinical neurological assessments (weeks 0, 20 and 52) were performed. RESULTS In the study group (AF and LA-Thrombi) 11 out of 32 pts. (34 %) displayed signs of acute (n = 8) or chronic (n = 3) cerebral embolism in the initial MRI studies. In 4 out of 32 pts. (13 %), MRI/DWI depicted new or additional cerebral emboli (n = 12) during the follow-up period despite continuous anticoagulation therapy. 2 (n = 2/4; 50 %) of these patients had clinically apparent neurological deficits. In the control group 1 out of 19 pts. (5 %) showed evidence of chronic cerebral embolism as assessed by MRI/DWI at the beginning of the study (week 0). No embolic cerebral lesions were detected during the 12-month follow-up. Within 12 months only 63 % (n = 20/32) of LA thrombi in the study group resolved completely under anticoagulation. CONCLUSION 1. The incidence of clinically inapparent cerebral emboli in pts. with newly diagnosed AF and atrial thrombi is much higher than the incidence of clinically apparent emboli and has been underestimated in the past. 2. New cerebral embolism may occur even with continued effective anticoagulation therapy in 13 % of pts. 3. Only 63 % of atrial thrombi resolve completely within 12 months under anticoagulation therapy.

PURPOSE:To prospectively evaluate the feasibility, image quality, and accuracy of coronary magnetic resonance (MR) angiography at 3.0 T in patients suspected of having coronary artery disease and to prospectively compare these results with those of coronary MR angiography performed at 1.5 T. MATERIALS AND METHODS:The study was approved by the institutional review board, and informed consent was obtained from all patients. Eighteen patients (11 men, seven women; mean age, 63 years; age range, 45-76 years) suspected of having coronary artery disease who were scheduled to undergo elective conventional coronary angiography (reference standard) were included. For coronary MR angiography at 3.0 and 1.5 T, a vector electrocardiographically gated three-dimensional segmented k-space gradient-echo imaging sequence was combined with real-time respiratory navigator gating and tracking. Signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), scores of image quality and sensitivity and specificity for the detection of coronary artery stenosis on a segment-by-segment basis were assessed at 3.0 and 1.5 T. Data were analyzed for statistical differences by using the Wilcoxon matched-pairs test and the McNemar test. RESULTS:The average increase in SNR at 3.0 T with respect to that at 1.5 T was 29.5% for the left coronary artery (LCA) and 31.2% for the right coronary artery (RCA) (P < .001), and the average increase in CNR was 21.8% for the LCA and 23.5% for the RCA (P < .001). Scores of image quality (P = .77) and diagnostic accuracy for the detection of coronary artery stenoses (sensitivity and specificity: 82% and 89%, respectively, at 3.0 T vs 82% and 88% at 1.5 T; P > .99) were identical or almost identical at both field strengths. CONCLUSION:Coronary MR angiography at 3.0 T is feasible in patients suspected of having coronary artery disease and yields significant increases in SNR and CNR, although current techniques do not result in significantly improved image quality and diagnostic accuracy compared with the quality and accuracy at 1.5 T. (c) RSNA, 2005.