Non-Enhanced MR Imaging of Cerebral Aneurysms: 7 Tesla versus 1.5 Tesla

Purpose To prospectively evaluate 7 Tesla time-of-flight (TOF) magnetic resonance angiography (MRA) in comparison to 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced magnetization-prepared rapid acquisition gradient-echo (MPRAGE) for delineation of unruptured intracranial aneurysms (UIA). Material and Methods Sixteen neurosurgical patients (male n = 5, female n = 11) with single or multiple UIA were enrolled in this trial. All patients were accordingly examined at 7 Tesla and 1.5 Tesla MRI utilizing dedicated head coils. The following sequences were obtained: 7 Tesla TOF MRA, 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced MPRAGE. Image analysis was performed by two radiologists with regard to delineation of aneurysm features (dome, neck, parent vessel), presence of artifacts, vessel-tissue-contrast and overall image quality. Interobserver accordance and intermethod comparisons were calculated by kappa coefficient and Lin's concordance correlation coefficient. Results A total of 20 intracranial aneurysms were detected in 16 patients, with two patients showing multiple aneurysms (n = 2, n = 4). Out of 20 intracranial aneurysms, 14 aneurysms were located in the anterior circulation and 6 aneurysms in the posterior circulation. 7 Tesla MPRAGE imaging was superior over 1.5 and 7 Tesla TOF MRA in the assessment of all considered aneurysm and image quality features (e.g. image quality: mean MPRAGE7T: 5.0; mean TOF7T: 4.3; mean TOF1.5T: 4.3). Ratings for 7 Tesla TOF MRA were equal or higher over 1.5 Tesla TOF MRA for all assessed features except for artifact delineation (mean TOF7T: 4.3; mean TOF1.5T 4.4). Interobserver accordance was good to excellent for most ratings. Conclusion 7 Tesla MPRAGE imaging demonstrated its superiority in the detection and assessment of UIA as well as overall imaging features, offering excellent interobserver accordance and highest scores for all ratings. Hence, it may bear the potential to serve as a high-quality diagnostic tool for pretherapeutic assessment and follow-up of untreated UIA.

[1]  Oliver Kraff,et al.  To TOF or not to TOF: strategies for non-contrast-enhanced intracranial MRA at 7 T , 2008, Magnetic Resonance Materials in Physics, Biology and Medicine.

[2]  X. Morandi,et al.  Time-of-flight MR angiography at 3T versus digital subtraction angiography in the imaging follow-up of 51 intracranial aneurysms treated with coils. , 2009, European journal of radiology.

[3]  J. R. Landis,et al.  The measurement of observer agreement for categorical data. , 1977, Biometrics.

[4]  Cristina Lavini,et al.  MR angiography at 3T versus digital subtraction angiography in the follow-up of intracranial aneurysms treated with detachable coils. , 2005, AJNR. American journal of neuroradiology.

[5]  G. Steinberg.  Controversy: clipping of asymptomatic intracranial aneurysm that is < 7 mm: yes. , 2013, Stroke.

[6]  W. Edelstein,et al.  The intrinsic signal‐to‐noise ratio in NMR imaging , 1986, Magnetic resonance in medicine.

[7]  Mark E Ladd,et al.  Caudal image contrast inversion in MPRAGE at 7 Tesla: problem and solution. , 2012, Academic radiology.

[8]  Ihar Volkau,et al.  Comparison of Magnetic Resonance Angiography Scans on 1.5, 3, and 7 Tesla Units: A Quantitative Study of 3‐Dimensional Cerebrovasculature , 2013, Journal of neuroimaging : official journal of the American Society of Neuroimaging.

[9]  H H Quick,et al.  New look at renal vasculature: 7 tesla nonenhanced T1‐weighted FLASH imaging , 2012, Journal of magnetic resonance imaging : JMRI.

[10]  J. Mocco,et al.  Rationale for treating unruptured intracranial aneurysms: actuarial analysis of natural history risk versus treatment risk for coiling or clipping based on 14,050 patients in the Nationwide Inpatient Sample database. , 2013, World neurosurgery.

[11]  G. Rinkel,et al.  Stability of Intracranial Aneurysms Adequately Occluded 6 Months after Coiling: A 3T MR Angiography Multicenter Long-Term Follow-Up Study , 2008, American Journal of Neuroradiology.

[12]  S. Leeder,et al.  A population based study , 1993, The Medical journal of Australia.

[13]  D. Hoult.  The principle of reciprocity in signal strength calculations—a mathematical guide , 2000 .

[14]  Antônio C. Santos,et al.  A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced) and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms , 2011, Clinics.

[15]  J M Wardlaw,et al.  What is the most sensitive non-invasive imaging strategy for the diagnosis of intracranial aneurysms? , 2001, Journal of neurology, neurosurgery, and psychiatry.

[16]  R. Shahzad,et al.  Detection and characterization of intracranial aneurysms: magnetic resonance angiography versus digital subtraction angiography. , 2011, Journal of the College of Physicians and Surgeons--Pakistan : JCPSP.

[17]  S. Kuroda,et al.  Size Ratio Can Highly Predict Rupture Risk in Intracranial Small (<5 mm) Aneurysms , 2013, Stroke.

[18]  D Chien,et al.  Evaluation of cerebral aneurysms with high-resolution MR angiography using a section-interpolation technique: correlation with digital subtraction angiography. , 1999, AJNR. American journal of neuroradiology.

[19]  Juha Hernesniemi,et al.  Impact of Early Surgery on Outcome After Aneurysmal Subarachnoid Hemorrhage: A Population‐Based Study , 1993, Stroke.

[20]  Mark E Ladd,et al.  Time-of-Flight Magnetic Resonance Angiography at 7 T Using Venous Saturation Pulses With Reduced Flip Angles , 2012, Investigative radiology.

[21]  H H Quick,et al.  Evaluation of Intracranial Aneurysms with 7 T versus 1.5 T Time-of-Flight MR Angiography – Initial Experience , 2009, RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin.

[22]  Peter Boesiger,et al.  Cardiac SSFP imaging at 3 Tesla , 2004, Magnetic resonance in medicine.

[23]  Johannes T Heverhagen,et al.  Time-of-Flight Magnetic Resonance Angiography at 7 Tesla , 2008, Investigative radiology.

[24]  L. Lin,et al.  A concordance correlation coefficient to evaluate reproducibility. , 1989, Biometrics.

[25]  M. Ladd,et al.  7 Tesla MPRAGE imaging of the intracranial arterial vasculature: nonenhanced versus contrast-enhanced. , 2013, Academic radiology.

[26]  N. Cox,et al.  A Note on the Concordance Correlation Coefficient , 2002 .

[27]  Jeroen Hendrikse,et al.  MR angiography of the cerebral perforating arteries with magnetization prepared anatomical reference at 7T: Comparison with time‐of‐flight , 2008, Journal of magnetic resonance imaging : JMRI.

[28]  H. Lanfermann,et al.  Comparison of intracranial 3D‐ToF‐MRA with and without parallel acquisition techniques at 1.5t and 3.0t: preliminary results , 2004, Acta radiologica.

[29]  Hiro Kiyosue,et al.  Diagnostic Accuracy of Magnetic Resonance Angiography for Cerebral Aneurysms in Correlation With 3D-Digital Subtraction Angiographic Images: A Study of 133 Aneurysms , 2002, Stroke.

[30]  J M Wardlaw,et al.  Intracranial aneurysms: CT angiography and MR angiography for detection prospective blinded comparison in a large patient cohort. , 2001, Radiology.

[31]  Jacob Cohen.  A Coefficient of Agreement for Nominal Scales , 1960 .

[32]  M. Ladd,et al.  Nonenhanced Magnetic Resonance Angiography of the Lower Extremity Vessels at 7 Tesla: Initial Experience , 2013, Investigative radiology.

[33]  George Tomlinson,et al.  Neurologic complications of cerebral angiography: prospective analysis of 2,899 procedures and review of the literature. , 2003, Radiology.

[34]  David F Kallmes,et al.  Complications of diagnostic cerebral angiography: evaluation of 19,826 consecutive patients. , 2007, Radiology.

[35]  Oliver Kraff,et al.  Seven-Tesla MRI of the female pelvis , 2013, European Radiology.

[36]  Horst Urbach,et al.  Time-of-flight MR angiography: comparison of 3.0-T imaging and 1.5-T imaging--initial experience. , 2003, Radiology.

[37]  W M Adams,et al.  The role of MR angiography in the pretreatment assessment of intracranial aneurysms: a comparative study. , 2000, AJNR. American journal of neuroradiology.

[38]  S. Riederer,et al.  Improved image quality of intracranial aneurysms: 3.0-T versus 1.5-T time-of-flight MR angiography. , 2004, AJNR. American journal of neuroradiology.