Morphological and Quantitative 7 T MRI of Hip Cartilage Transplants in Comparison to 3 T—Initial Experiences

Lazik-Palm, Andrea; Kraff, Oliver; Johst, Sören; Quick, Harald H.; Ladd, Mark E.; Geis, Christina; Körsmeier, Konrad; Landgraeber, Stefan; Theysohn, Jens

doi:10.1097/rli.0000000000000264

Cited by 15 publications

(30 citation statements)

References 37 publications

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“…As the 8Tx/Rx body array, which served as the standard of reference in this work, has already been used in a broad variety of clinical 7T MRI investigations, [32][33][34][35][36][37][38][39][40] the improved performance of the new combined array holds great promise for 7T UHF body MRI, increasing either the spatial resolution of these examinations or speeding up the acquisition time through use of higher parallel imaging factors. Imaging results in the pelvis of a female volunteer showed high homogeneity at a very high resolution of 0.68 9 0.68 9 0.68 mm³, which was achieved within less than 10 min acquisition time.…”

Section: Discussionmentioning

confidence: 99%

7T ultra‐high field body MR imaging with an 8‐channel transmit/32‐channel receive radiofrequency coil array

et al. 2018

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Section: Discussionmentioning

confidence: 99%

7T ultra‐high field body MR imaging with an 8‐channel transmit/32‐channel receive radiofrequency coil array

et al. 2018

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“…The applied standard sequences were chosen in accordance with the protocol recommendations for shoulder imaging of the German society of radiology [21] and complemented by a range of additional sequences from other joint protocols already existing in our library [11,22]. In total, ten sequences were included in the protocol, balancing a maximum of variety for evaluation in limited examination time.…”

Section: Imaging Protocolmentioning

confidence: 99%

“…Ultra-high field (UHF), in particular 7-T, MRI systems have been established and evaluated during the last decade to approach this challenge. At more than 60 sites worldwide, a substantial quantity of investigations has shown diagnostic improvements in several parts of the body, i.e., in the brain [9], the heart [10], or the hip [11] as well as the possibility to reduce the amount of injected contrast media [12,13]. These achievements are mainly based on the higher spatial resolution and better tissue contrast at UHF [14].…”

Section: Introductionmentioning

confidence: 99%

7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff

et al. 2020

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Background: To evaluate feasibility and diagnostic performance of clinical 7-T magnetic resonance imaging (MRI) of the shoulder.Methods: Eight patients with suspected lesions of the rotator cuff underwent 7-T MRI before arthroscopy. Image quality was scored for artifacts, B 1 + inhomogeneities, and assessability of anatomical structures. A structured radiological report was compared to arthroscopy. In four patients, a visual comparison with pre-existing 1.5-T examinations was performed. Results: Regarding image quality, the majority of the sequences reached values above the middle of each scoring scale. Fat-saturated proton density sequences showed least artifacts and best structure assessability. The most homogenous B 1 + field was reached with gradient-echo sequences. Arthroscopy did not confirm tendinopathy/ partial tear of supraspinatus in 5/8 patients, of subscapularis in 5/6, and of infraspinatus in one patient; only a partial lesion of the subscapularis tendon was missed. Pathologic findings of long bicipital tendon, acromioclavicular joint, glenohumeral cartilage, labrum, and subacromial subdeltoideal bursa were mainly confirmed; exceptions were one lesion of the long bicipital tendon, one subacromial bursitis, and one superior glenoid labrum anterior-to-posterior lesion, missed on 7-T MRI. Evaluating all structures together, sensitivity was 86%, and specificity 74%. A better contrast and higher image resolution was noted in comparison to previous 1.5-T examinations. Conclusions: 7-T MRI of the shoulder with diagnostic image quality is feasible. Overrating of tendon signal alterations was the main limitation. Although the diagnostic performance did not reach the current results of 3-T MRI, our study marks the way to implement clinical 7-T MRI of the shoulder.

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“…This may affect the quality of the inversion pulse for the IR and LL experiments, but may also make B 1 correction approaches necessary for the VFA and LL techniques [ 14 , 15 ]. For dGEMRIC at 7 T, IR [ 16 ] and VFA [ 17 , 18 ] have previously been used for T 1 mapping, but as no quantitative comparison between the methods has been performed, further investigation is needed to find the optimal T 1 -mapping approach at ultra-high field strength.…”

Section: Introductionmentioning

confidence: 99%

Knee dGEMRIC at 7 T: comparison against 1.5 T and evaluation of T1-mapping methods

Peterson¹,

Tiderius²,

Olsson³

et al. 2018

BMC Musculoskelet Disord

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BackgrounddGEMRIC (delayed Gadolinium Enhanced Magnetic Resonance Image of Cartilage) is a well-established technique for cartilage quality assessment in osteoarthritis at clinical field strengths. The method is robust, but requires injection of contrast agent and a cumbersome examination procedure. New non-contrast-agent-based techniques for cartilage quality assessment are currently being developed at 7 T. However, dGEMRIC remains an important reference technique during this development. The aim of this work was to compare T1 mapping for dGEMRIC at 7 T and 1.5 T, and to evaluate three T1-mapping methods at 7 T.MethodsThe knee of 10 healthy volunteers and 9 patients with early signs of cartilage degradation were examined at 1.5 T and 7 T after a single (one) contrast agent injection (Gd-(DTPA)2−). Inversion recovery (IR) sequences were acquired at both field strengths, and at 7 T variable flip angle (VFA) and Look-Locker (LL) sequences were additionally acquired. T1 maps were calculated and average T1 values were estimated within superficial and deep regions-of-interest (ROIs) in the lateral and medial condyles, respectively.ResultsT1 values were 1.8 (1.4–2.3) times longer at 7 T. A strong correlation was detected between 1.5 T and 7 T T1 values (r = 0.80). For IR, an additional inversion time was required to avoid underestimation (bias±limits of agreement − 127 ± 234 ms) due to the longer T1 values at 7 T. Out of the two 3D sequences tested, LL resulted in more accurate and precise T1 estimation compared to VFA (average bias±limits of agreement LL: 12 ± 202 ms compared to VFA: 25 ± 622 ms). For both, B1 correction improved agreement to IR.ConclusionWith an adapted sampling scheme, dGEMRIC T1 mapping is feasible at 7 T and correlates well to 1.5 T. If 3D is to be used for T1 mapping of the knee at 7 T, LL is preferred and VFA is not recommended. For VFA and LL, B1 correction is necessary for accurate T1 estimation.

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Morphological and Quantitative 7 T MRI of Hip Cartilage Transplants in Comparison to 3 T—Initial Experiences

Cited by 15 publications

References 37 publications

7T ultra‐high field body MR imaging with an 8‐channel transmit/32‐channel receive radiofrequency coil array

7T ultra‐high field body MR imaging with an 8‐channel transmit/32‐channel receive radiofrequency coil array

7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff

Knee dGEMRIC at 7 T: comparison against 1.5 T and evaluation of T1-mapping methods

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