Name: protocol for the evaluation of mri artifacts caused by metal implants to assess the suitability of implants and the vulnerability of pulse sequences
Uploaded: 2018-05-17T14:00:00.000+00:00
Duration: 8 min 19 s
Description: Watch this Scientific Journal Video about Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences at JoVE.c

著者は、ステファニー ザウアー、薬剤師、薬局ハイデルベルク大学病院、MRI ファントムへの彼女の貢献のために感謝したいです。さらに、16 チャンネル多目的コイルのプロトタイプを提供するため NORAS MRI 製品 GmbH (ドイツ、Höchberg)、特にダニエル Gareis に感謝したいと思います。さらに、シーメンス医療 GmbH (ドイツ ・ エアランゲン) と特にマティアス Nittka 順序の設定に彼らの支援の協力に感謝しております。

1. ファントムの準備
<ol><li>インプラントのボリューム (例えば、水変位法を用いた) を決定します。 注: CCT T サンプルと Z T サンプル量測定 0.65 mL と 0.73 mL は、それぞれ。</li>
	<li>非磁性、プラスチック、防水ボックスの真ん中に細い糸を使用してインプラントの位置を修正します。予想される MRI 成果物よりも大きいボックスを使用します。 注: 興味のインプラントおよび/またはパルス シーケンスのアーティファクト ボリュームの概算値を使用できない場合は、テスト スキャンを実行ボックスに、約 10 倍にもファントム、ファントムを配置することによって、水で満たされました。このアーティファクト ボリュームは研究 (CCT T サンプル) の 7.3 ミリリットルから 0.09 mL (Z T サンプル) の範囲。</li>
	<li>
慎重に 50 ° C の水浴を使用して半合成脂肪 (58.8%)、水 (40%)、ステアリン酸マクロゴール-8 (1.2%) の混合物を溶融します。 注意: 本研究でサンプルは、各サンプルの埋め込みを 500 mL の混合物を使用しました。<ol>
<li>混合物では、液体になると、暖房を停止、ゆっくり攪拌しながら、開始し、加熱を停止します。脂肪と水の段階の分離がないことを確認します。</li>
	</ol>
</li>
	<li>すぐに凝固が始まると、徐々 に混合物でインプラントを埋め込むことが開始されます。インプラントとファントムのボックスに埋め込みの混合物をゆっくり注ぐ。 注: は、空気混入を避けるためにゆっくりと実行する必要があります注ぐ。</li>
	<li>4 ° c 乾燥で一晩冷蔵庫に埋め込まれたインプラントに幻のボックスを配置します。次の日は、デカンテーションによって任意の残留流体部品を削除します。</li>
</ol>2. MRI 検査
<ol><li>体内の状況のように同じ向きで MRI ファントム (埋め込まれたインプラントとボックス) を配置します。MRI のアイソ センターの中の幻の中間を位置します。</li>
	<li>測定、(例えば、頭部コイル) の重度かつ明白な信号低下なし画像ボリューム内で均一信号分布を可能にするコイルを使用します。</li>
	<li>MRI コンソールでスキャン、MRI を計画するときは、ボックスの端にいくつかの空気を含む幻のボックスがイメージングのボリューム内にあるを確認します。</li>
	<li>次に、MRI 検査を実行します。</li>
</ol>3. 画像解析と後処理
<ol><li>MRI のコンソール (例えば、DICOM 形式を使用して) から (例えば、圧縮によって) の品質を損なうことがなく画像をエクスポートします。後処理ソフトウェア評価 (材料の表を参照してください) 分割ボリュームの定量化、しきい値に基づくセグメンテーション、ROI 信号強度の利益率 (ROI) の領域を配置することができます MRI で画像をインポートします。</li>
	<li>
パイルアップ アーティファクトのしきい値を定義して、イメージング ボリューム内で均一な信号の分布を確認、線目に見える人工物の外側の境界線に隣接して互いに垂直に配置最大アイテム サイズ (スライス図 1 a)。 注: パイルアップ アーティファクト、変位成果物、人工的に高い信号強度とエリアを呈したします。彼らは、スライス方向読み出し方向に発生します。<ol>
<li>それぞれ 4 つの交点 (図 1 a) の外の直径で 10 mm 背景 ROI (投資収益率の背景) を配置します。行と興味セグメンテーション エディターを使用して背景領域を配置します。</li>
		<li>平均信号強度とすべてボクセルごとの投資収益率の背景これら 4 つの投資収益率の背景値内の標準偏差 (SD) を個別に測定します。プロジェクト ビューでマテリアルの統計ツールを使用します。</li>
		<li>それぞれの投資収益率の背景の平均信号強度が均一な信号の流通を保証する他の 3 つの対応のそれぞれの平均信号の ± 1.5 SD の範囲内にあることを確認します。</li>
		<li>パイルアップ アーティファクトのしきい値を計算するには、これらの 4 つの投資収益率の背景値のすべての画素の平均信号強度に 3 SD の関心領域の背景をします。パイルアップ成果物の半自動閾値に基づく領域分割を実行するには、すべてのスライスの信号損失アーティファクトに隣接するしきい値より大きい信号強度を持つすべての画素を選択します。セグメンテーション エディターのマスキング ツールを使用して、事前定義されたシグナル強度の範囲を視覚化し、それを分割を制限します。</li>
	</ol>
</li>
	<li>
信号損失アーチファクトのしきい値を定義するには、利益 (ROIs) の 4 地域が、含気領域 (ROI空気; 各直径 10 mm) 幻のボックスのコーナーで、これら 4 ROI 内すべてのボクセルの SD 平均信号強度を測定空気手順 3.2、セグメンテーション エディターと「材料統計」、をそれぞれ使用。 注: 人工低信号強度を有するボクセルと信号損失の成果物を提示します。位相緩和と変位の成果物によって引き起こされます。<ol>
<li>低信号強度 (図 1 a) の最も大きい接続された領域によって定義される信号損失アーティファクト (ROIコア) のコアに ROI を配置します。手動で平均信号強度が平均投資収益率空気+ それぞれの SD の 3 倍より低い信号損失の成果物の内で可能な最大サイズが見つかるまでは、投資収益率コアのサイズを増やします。最後に、平均信号強度を測定、投資収益率コアの SD。</li>
		<li>3 を追加することによって信号損失アーチファクトの信号強度閾値を計算する投資収益率コアの平均に投資収益率コアの SD。信号損失アーチファクトの半自動閾値に基づく領域分割を実行するには、しきい値を下回る信号強度と ROIコアに接続されているすべての画素を選択します。</li>
		<li>セグメンテーション エディターのマスキング ツールを使用して、事前定義されたシグナル強度の範囲を視覚化し、それを分割を制限します。可能であれば、タップ セグメンテーション エディターの「選択」で「塗りつぶし」関数を使用して、選択されていない分割内すべてのボクセルを含めます。該当する場合は、手動で追加の明確な信号損失アーチファクトをセグメンテーションに追加します。</li>
	</ol>
</li>
	<li>真のアーティファクトのボリュームを取得する計算されたアーティファクト ボリュームから物理的なインプラント ボリュームを減算します。少なくとも 3 解析を繰り返す x。少なくとも 2 週間の間隔学習バイアスを除外する複数の読み取りを分ける必要があります。</li>
</ol>

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ティム ・ Hilgenfeld、フランツ ・ s ・ Schwindling、アレクサンドル ・ Juerchott、ハイデルベルク大学医学部ポスドク研究員プログラムから資金を受けてください。研究は、ディートマー ・ ホップ 【 (プロジェクト号 23011228) によって部分的に支えられました。著者は、この記事に関連して利益相反がないことを明示的に述べています。

金属と患者数のインプラントし、MRI 検査数は現在1,2,3を増加しています。過去には、関節置換術後後 MRI 検査は避けた。今日、MRI はこのような患者をイメージングのみ要求されませんしかし、また合併症の評価のため人工関節置換術に隣接できるはず。したがって、MRI の安全や金属アーチファクト抑制のため堅牢なパル?...

MRI は、診断に欠かせないツールになっています。その結果、定期的な診断に使用される MRI システムの数には、1が一層強まっています。同時に、インプラントの患者数は2,3も高まっています。2012 年に、例えば、以上 100 万の膝と関節置換術で行われている米国だけで4。このようなインプラントの有病率は約 700 万 2010年では、年齢グループの 80 ~ 89 歳5女性の 10% 以上に相当します。その結果、画像品質と MRI 検査の診断的意義は、金属製インプラントは、診断精度を低下の結果による成果物によってしばしば障害者します。したがって、インプラントの MRI 適合性とパルス シーケンスのアーティファクトの脆弱性は、ますます重要になっています。多数のアプローチは、これらの特性を評価するために公開されています。使用される評価の方法で厳密な差異は、それぞれの結果が、比較するは難しいです。
材料の MRI 適合性の評価は、その磁化率6を計算することによって実行できます。ただし、成果物に対する異なるパルス シーケンスの脆弱性は、与えられたインプラントのアプローチでは比較できません。その逆、与えられたパルス シーケンスのアーティファクト ボリュームのみ概算できます別のインプラント。さらに、分析はしばしば人工的に形をしたインプラント7,8で実行されます。材料の容積や形状、アーティファクト サイズ6に影響を及ぼすが、これらの機能に同様にアカウントが考慮必要があります。帯磁する代わりに、アイテムのサイズを評価できます。頻繁に研究はインプラント アーティファクト10,11の 1 つのスライスをカバーして二次元アイテム サイズ焦点またはアーティファクト サイズ9の定性的な評価に依存します。また、マニュアルでのセグメンテーションのアプローチは、時間がかかるだけでなく、イントラ間読みだし違い11にもなりやすいですしばしば、使用されます。最後に、プロトコルよくできないように同じ時間12- 脂肪-飽和脂肪飽和し、シーケンスをテストします。これは、ただし、望ましいでしょう、応用脂肪抑制法深くアーティファクトのサイズに影響を与えるので。
ここでは、プロトコルは、信頼性の高い、半自動を信号の損失と盛り上がりの成果物の全体のインプラントやインプラントの目に見える成果物を含むすべてのスライスの閾値に基づく、三次元定量化を提案します。さらに、T1 と T2 強調画像脂肪飽和の有無をテストできます。プロトコルは、異なるインプラントの MRI 適合性または特定のインプラントの金属の人工物に異なるパルス シーケンスの脆弱性を評価する使用することができます。

<table><tbody><tr><td>Aqua B. Braun Ecotainer</td><td>B. Braun Melsungen AG, Melsungen, Germany</td><td></td><td></td></tr><tr><td>Semisynthetic fat: Witepsol W25</td><td>Caelo Caesar &amp;amp; Loretz GmbH, Hilder, Germany</td><td>4051</td><td></td></tr><tr><td>Macrogol-8-stearate</td><td>Caelo Caesar &amp;amp; Loretz GmbH, Hilder, Germany</td><td>3023</td><td></td></tr><tr><td>Plastic box: not specified</td><td></td><td></td><td></td></tr><tr><td>Implants: Nobel Replace</td><td>Nobel Biocare, Z&amp;uuml;rich, Switzerland</td><td></td><td></td></tr><tr><td>Water bath Haake S5P</td><td>Thermo Scientific, Waltham, MA, USA</td><td></td><td></td></tr><tr><td>Measuring cylinder Blaubrand Eterna, Class A, Boro 3.3</td><td>BRAND GmbH + Co Kg, Wertheim, Germany</td><td>32708</td><td></td></tr><tr><td>Coil: Variety</td><td>Noras MRI products GmbH, H&amp;ouml;chberg, Germany</td><td></td><td></td></tr><tr><td>MRI: Magnetom Trio</td><td>Siemens Healthcare GmbH, Erlangen, Germany</td><td></td><td></td></tr><tr><td>Postprocesing software: Amira 6.4</td><td>Thermo Scientific, Waltham, MA, USA</td><td></td><td></td></tr></tbody></table>

protocol for the evaluation of mri artifacts caused by metal implants to assess the suitability of implants and the vulnerability of pulse sequences

磁気共鳴画像 (MRI) スキャナー、医療用インプラント症例の数が増え続けて、放射線科医はますます縮小画像品質の結果、MRI に金属インプラント関連成果物を発生します。したがって、イメージのアーティファクトを軽減するパルス シーケンスの開発と同様、アーティファクト ボリュームの面でインプラントの MRI 適合性は、ますます重要になって。ここでは、MRI 上のインプラントのアーティファクト ボリュームの標準化された評価を可能にする包括的なプロトコルを提案する.さらに、このプロトコルは、成果物に対する異なるパルス シーケンスの脆弱性を分析する使用できます。提案プロトコルは、T1 と T2 強調画像脂肪抑制およびすべて受動的なインプラントの有無に適用できます。さらに、このストアド プロシージャは、信号の損失と盛り上がりのアーチファクトの別と三次元の識別できます。前の調査はすこぶる評価方法とその結果の比較可能性は限られていた。したがって、MRI アーチファクト ボリュームの標準化された測定がよりよい比較を提供するために必要です。これは、インプラントの MRI 適合性の開発を改善しより良い最終的に患者のケアを改善するためにシーケンスをパルスします。

上記プロトコルを評価したアーティファクト 2 異なる歯科インプラント製チタン (T; 参照テーブルの材料) サポート異なる樹冠量 [金属磁器非貴金属合金 (CCT T) とモノリシックジルコニア (Z T);図 1 bと1 c]。CCT T サンプルを表す大きな成果物の予測高常磁性材料組成 (コバルト 61%、クロム 21%、およびタングステン 11%;CCT)。Z ...

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Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

磁気共鳴イメージングのためのインプラントの適合性および/または金属アーティファクトに対する異なるパルス シーケンスの脆弱性を推定するためのインプラントに磁気共鳴画像アーチファクトを評価する標準化された手法について述べる同時に。

インプラントの適合性とパルス シーケンスの脆弱性を評価するためにインプラントの金属による MRI アーチファクトの評価のためのプロトコル

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter ...

protocol-for-evaluation-mri-artifacts-caused-metal-implants-to-assess

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

9.8K ビュー.  Heidelberg University Hospital. 磁気共鳴イメージングのためのインプラントの適合性および/または金属アーティファクトに対する異なるパルス シーケンスの脆弱性を推定するためのインプラントに磁気共鳴画像アーチファクトを評価する標準化された手法について述べる同時に。

ビデオ: Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

Tracking the Mammary Architectural Features and Detecting Breast Cancer with Magnetic Resonance Diffusion Tensor Imaging

Breast cancer is the most common cause of cancer among women worldwide. Early detection of breast cancer has a critical role in improving the quality of life and survival of breast cancer patients. In this paper a new approach for the detection of breast cancer is described, based on tracking the mammary architectural elements using diffusion tensor imaging (DTI). 
The paper focuses on the scanning protocols and image processing algorithms and software that were designed to fit the diffusion properties of the mammary fibroglandular tissue and its changes during malignant transformation. The final output yields pixel by pixel vector maps that track the architecture of the entire mammary ductal glandular trees and parametric maps of the diffusion tensor coefficients and anisotropy indices. 
The efficiency of the method to detect breast cancer was tested by scanning women volunteers including 68 patients with breast cancer confirmed by histopathology findings. Regions with cancer cells exhibited a marked reduction in the diffusion coefficients and in the maximal anisotropy index as compared to the normal breast tissue, providing an intrinsic contrast for delineating the boundaries of malignant growth. Overall, the sensitivity of the DTI parameters to detect breast cancer was found to be high, particularly in dense breasts, and comparable to the current standard breast MRI method that requires injection of a contrast agent. Thus, this method offers a completely non-invasive, safe and sensitive tool for breast cancer detection.

We describe how to obtain parametric and vector maps of the diffusion tensor of the breast using magnetic resonance imaging. The protocol and final output following imaging processing are tailored for tracking breast architectural features and detecting breast malignancy.

乳腺アーキテクチャの特長を追跡し、磁気共鳴拡散テンソルイメージングと乳がんの検出

Breast cancer is the most common cause of cancer among women worldwide. Early detection of breast cancer has a critical role in improving the quality of ...

医学

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization. The qMRI portion of the protocol includes measurements of the longitudinal and transverse relaxation time constants (T1 and T2, respectively). Also acquired are diffusion-tensor MRI data, in which water diffusivity is measured and used to infer pathological processes such as edema. Quantitative magnetization transfer imaging is used to characterize the relative tissue content of macromolecular and free water protons. Lastly, fat-water MRI methods are used to characterize fibro-adipose tissue replacement of muscle. In addition to describing the data acquisition and analysis procedures, this paper also discusses the potential problems associated with these methods, the analysis and interpretation of the data, MRI safety, and strategies for artifact reduction and protocol optimization.

Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using non-invasive magnetic resonance imaging methods.

骨格筋疾患の定量的磁気共鳴イメージング

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of ...

A Multicenter MRI Protocol for the Evaluation and Quantification of Deep Vein Thrombosis

We evaluated a magnetic resonance venography (MRV) approach with gadofosveset to quantify total thrombus volume changes as the principal criterion for treatment efficacy&#160;in a multicenter randomized study comparing edoxaban monotherapy with a heparin/warfarin regimen for acute, symptomatic lower extremities deep vein thrombosis (DVT) treatment. We also used a direct thrombus imaging approach (DTHI, without the use of a contrast agent) to quantify fresh thrombus. We then sought to evaluate the reproducibility of the analysis methodology and applicability of using 3D magnetic resonance venography and direct thrombus imaging for the quantification of DVT in a multicenter trial setting. From 10 randomly selected subjects participating in the edoxaban Thrombus Reduction Imaging Study (eTRIS), total thrombus volume in the entire lower extremity deep venous system was quantified bilaterally. Subjects were imaged using 3D-T1W gradient echo sequences before (direct thrombus imaging, DTHI) and 5 min after injection of 0.03 mmol/kg of gadofosveset trisodium (magnetic resonance venography, MRV). The margins of the DVT on corresponding axial, curved multi-planar reformatted images were manually delineated by two observers to obtain volumetric measurements of the venous thrombi. MRV was used to compute total DVT volume, whereas DTHI was used to compute volume of fresh thrombus. Intra-class correlation (ICC) and Bland Altman analysis were performed to compare inter and intra-observer variability of the analysis. The ICC for inter and intra-observer variability was excellent (0.99 and 0.98, p &#60;0.001, respectively) with no bias on Bland-Altman analysis for MRV images. For DTHI images, the results were slightly lower (ICC = 0.88 and 0.95 respectively, p &#60;0.001), with bias for inter-observer results on Bland-Altman plots. This study showed feasibility of thrombus volume estimation in DVT using MRV with gadofosveset trisodium, with good intra- and inter-observer reproducibility in a multicenter setting.

The goal of this study is to use magnetic resonance venography with long-circulating gadolinium-based contrast agent and direct thrombus imaging for quantitative evaluation of DVT volume in a multicenter, clinical trial setting. Inter- and intra-observer variability assessments were conducted, and reproducibility of the protocol was determined.

深部静脈血栓症の評価と定量化のための多施設MRIプロトコル

We evaluated a magnetic resonance venography (MRV) approach with gadofosveset to quantify total thrombus volume changes as the principal criterion for ...

Optogenetic Functional MRI

The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states.

This protocol describes the steps and data analysis required to successfully perform optogenetic functional magnetic resonance imaging (ofMRI). ofMRI is a novel technique that combines high-field fMRI readout with optogenetic stimulation, allowing for cell type-specific mapping of functional neural circuits and their dynamics across the whole living brain.

光遺伝学機能MRI

The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional ...

神経科学

Equipment Setup and Artifact Removal for Simultaneous Electroencephalogram and Functional Magnetic Resonance Imaging for Clinical Review in Epilepsy

Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that provides synergy in the understanding and localization of seizure onset in epilepsy. However, reported experimental protocols for EEG-fMRI recordings fail to address details about conducting such procedures on epilepsy patients. In addition, these protocols are limited solely to research settings. To fill the gap between patient monitoring in an epilepsy monitoring unit (EMU) and conducting research with an epilepsy patient, we introduce a unique EEG-fMRI recording protocol of epilepsy during the interictal period. The use of an MR conditional electrode set, which can also be used in the EMU for a simultaneous scalp EEG and video recording, allows an easy transition of EEG recordings from the EMU to the scanning room for concurrent EEG-fMRI recordings. Details on the recording procedures using this specific MR conditional electrode set are provided. In addition, the study explains step-by-step EEG processing procedures to remove the imaging artifacts, which can then be used for clinical review. This experimental protocol promotes an amendment to the conventional EEG-fMRI recording for enhanced applicability in both clinical (i.e., EMU) and research settings. Furthermore, this protocol provides the potential to expand this modality to postictal EEG-fMRI recordings in the clinical setting.

This article details simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) recording procedures that can be used in both clinical and research settings. EEG processing procedures to remove imaging artifacts for clinical review are also included. This study focuses on the example of epilepsy during the interictal period.

てんかんの臨床レビューのための脳波と機能的磁気共鳴画像の同時診断のための機器のセットアップとアーチファクト除去

Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that provides synergy in the ...

生物工学

Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The appearance of a mass on certain magnetic resonance (MR) sequences can help differentiate a thrombus from competing diagnoses such as a tumor. T1 and T2 signal characteristics of a thrombus are related to the evolution of hemoglobin properties. A thrombus typically does not enhance following contrast administration, which also helps differentiation from a tumor. We also highlight the emerging role of T1 mapping in the evaluation of a thrombus, which can add another level of support in diagnosis. Prior to any CMR exam, patient screening and interviews are critical to ensure safety and to optimize patient comfort. Effective communication during the exam between the technologist and the patient promotes proper breath holding technique and higher quality images. Volumetric post processing and structured reporting are helpful to ensure that the radiologist answers the ordering services&#39; question and communicates these results effectively. Optimal pre-MR safety evaluation, CMR exam execution, and post exam processing and reporting allow for delivery of high quality radiological service in the evaluation of a suspected cardiac thrombus.

The goal of this article is to describe how cardiac magnetic resonance can be used for the evaluation and diagnosis of a suspected cardiac thrombus. The method presented will describe data acquisition as well as the pre-procedure and post-procedure protocol.

疑わしい心臓血栓の評価のための心臓磁気共鳴:従来技術と新興技術

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The ...

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI

Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), EEG-fMRI, combines the complementary properties of scalp EEG (good temporal resolution) and fMRI (good spatial resolution) to measure neuronal activity during an electrographic event, through hemodynamic responses known as blood-oxygen-level-dependent (BOLD) changes. It is a non-invasive research tool that is utilized in neuroscience research and is highly beneficial to the clinical community, especially for the management of neurological diseases, provided that proper equipment and protocols are administered during data acquisition. Although recording EEG-fMRI is apparently straightforward, the correct preparation, especially in placing and securing the electrodes, is not only important for safety but is also critical in ensuring the reliability and analyzability of the EEG data obtained. This is also the most experience-demanding part of the preparation. To address these issues, a straightforward protocol that ensures data quality was developed. This article provides a step-by-step guide for acquiring reliable EEG data during EEG-fMRI using this protocol that utilizes readily available medical products. The presented protocol can be adapted to different applications of EEG-fMRI in research and clinical settings, and may be beneficial to both inexperienced and expert operators.

This article provides a straightforward protocol for acquiring good quality electroencephalography (EEG) data during simultaneous EEG and functional magnetic resonance imaging by utilizing readily available medical products.

同時脳波と機能MRIにおける脳波データの確実な取得

Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), EEG-fMRI, combines the complementary properties of scalp EEG ...

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in multiple sclerosis (MS) patients. MS is a chronic inflammatory, demyelinating, neurodegenerative disease that is characterized by white and gray matter lesions. Detection of spatially and temporally disseminated T2-hyperintense lesions by the use of MRI at 1.5 T and 3 T represents a crucial diagnostic tool in clinical practice to establish accurate diagnosis of MS based on the current version of the 2017 McDonald criteria. However, the differentiation of MS lesions from brain white matter lesions of other origins can sometimes be challenging due to their resembling morphology at lower magnetic field strengths (typically 3 T). Ultrahigh field MR (UHF-MR) benefits from increased signal-to-noise ratio and enhanced spatial resolution, both key to superior imaging for more accurate and definitive diagnoses of subtle lesions. Hence, MRI at 7.0 T has shown encouraging results to overcome the challenges of MS differential diagnosis by providing MS-specific neuroimaging markers (e.g., central vein sign, hypointense rim structures and differentiation of MS grey matter lesions). These markers and others can be identified by other MR contrasts other than T1 and T2 (T2*, phase, diffusion) and substantially improve the differentiation of MS lesions from those occurring in other neuroinflammatory conditions such as neuromyelitis optica and Susac syndrome. In this article, we describe our current technical approach to study cerebral white and grey matter lesions in MS patients at 7.0 T using different MR acquisition methods. The up-to-date protocol includes the preparation of the MR setup including the radio-frequency coils customized for UHF-MR, standardized screening, safety and interview procedures with MS patients, patient positioning in the MR scanner and acquisition of dedicated brain scans tailored for examining MS.

Here, we present a protocol to acquire magnetic resonance (MR) images of multiple sclerosis (MS) patient brains at 7.0 Tesla. The protocol includes preparation of the setup including the radio-frequency coils, standardized interview procedures with MS patients, subject positioning in the MR scanner and MR data acquisition.

7.0テスラにおける多発性硬化症の磁気共鳴画像

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in ...

Clinical Indications for Rapid Sequence MRI in Pediatric Neurosurgical Patients and the Limitations and Barriers to Implementation

Rapid and fast magnetic resonance imaging (MRI) protocols have become increasingly popular for pediatric neurosurgical patients as they are a great way to reduce ionizing radiation and sedation. While their popularity has increased, there are hurdles to overcome when transitioning to using them clinically, such as cost, staffing training, and motion artifact. Through this paper, we developed a protocol for clinical applications where rapid MRI can be a substitute or adjuvant in diagnostic workup. Further, we outline the relevant literature for the use of RS-MRI for the spine, TBI, and hydrocephalus pathologies while expanding upon the limitations and logistical barriers when transitioning to their use, a few of which are discussed above. Through this, we conclude that RS-MRI can be used diagnostically for spinal pathologies such as syrinx and hydrocephalus. Further, its lack of sensitivity for TBI findings makes rapid sequence magnetic resonance imaging (RS-MRI) a strong adjuvant with other advanced imaging or computed tomography (CT) for traumatic brain injury (TBI) pathologies.

Here, we present a protocol to increase the use of rapid sequence magnetic resonance imaging (RS-MRI) for pediatric patients for spine, traumatic brain injury (TBI), and hydrocephalus while documenting limitations and barriers to universal implementation.

Rapid and fast magnetic resonance imaging (MRI) protocols have become increasingly popular for pediatric neurosurgical patients as they are a great way to ...

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI scanners were crude, but advances in digital computing and electronics led to their advancement over any other technique for precise imaging, especially in discovering tumors. Compared to other diagnostic imaging techniques like computed tomography and X-ray, MRI does not expose patients to radiation.
The drawbacks of MRI scans include their much higher cost and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded. The patient must be enclosed in a metal tube-like device for the duration of the scan, sometimes as long as thirty minutes, which can be uncomfortable and impractical for ill patients. The machine is also so noisy that, even with earplugs, patients can become anxious or fearful. These problems have been overcome somewhat with the development of &#34;open&#34;&#160;MRI scanning, which does not require the patient to be entirely enclosed in a metal tube. Patients with iron-containing metallic implants (internal sutures, some prosthetic devices, pacemakers and so on) cannot undergo MRI scanning because it can dislodge these implants.
Different images are formed depending on the time taken between the sequence of magnetic pulses and the receipt and interpretation of the signal. A T1-weighted image has fatty tissues appearing brighter due to their enhanced signal while suppressing water signals, making it appear darker. In contrast, the T2-weighted image shows an enhanced water signal. Further, using MRI contrast media or dyes, like gadolinium, helps improve the quality of the images. Usually injected into the patient&#39;s vein, the gadolinium contrast dyes contain strongly paramagnetic gadolinium (Gd), which has positive magnetic susceptibility. When placed in a magnetic field, it is not directly seen in the MRI result but helps shorten the T1 values in tissues, where it accumulates, which allows the tissues to appear brighter in T1-weighted images.
Functional MRIs (fMRI), which detect the concentration of blood flow in certain body parts, are increasingly being used to study the activity in parts of the brain during various body activities. This has helped scientists learn more about the locations of different brain functions and more about brain abnormalities and diseases. More recently, 4D flow MRI provides 3D blood flow images and hemodynamics, with the fourth dimension being time, allowing cardiovascular disease assessment through the 3D coverage of the anatomy and velocity.
This content is derived from <a href="https://openstax.org/books/anatomy-and-physiology/pages/1-7-medical-imaging">Openstax, Anatomy and Physiology, Section 1.7: Medical Imaging</a>

磁気共鳴画像法

Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which ...

インプラントの適合性とパルスシーケンスの脆弱性を評価するためにインプラントの金属による MRI アーチファクトの評価のためのプロトコル

要約

さらに動画を探す

この動画の章

乳腺アーキテクチャの特長を追跡し、磁気共鳴拡散テンソルイメージングと乳がんの検出

骨格筋疾患の定量的磁気共鳴イメージング

深部静脈血栓症の評価と定量化のための多施設MRIプロトコル

光遺伝学機能MRI

てんかんの臨床レビューのための脳波と機能的磁気共鳴画像の同時診断のための機器のセットアップとアーチファクト除去

疑わしい心臓血栓の評価のための心臓磁気共鳴:従来技術と新興技術

同時脳波と機能MRIにおける脳波データの確実な取得

7.0テスラにおける多発性硬化症の磁気共鳴画像

Clinical Indications for Rapid Sequence MRI in Pediatric Neurosurgical Patients and the Limitations and Barriers to Implementation

磁気共鳴画像法

インプラントの適合性とパルス シーケンスの脆弱性を評価するためにインプラントの金属による MRI アーチファクトの評価のためのプロトコル

要約

さらに動画を探す

この動画の章

乳腺アーキテクチャの特長を追跡し、磁気共鳴拡散テンソルイメージングと乳がんの検出

骨格筋疾患の定量的磁気共鳴イメージング

深部静脈血栓症の評価と定量化のための多施設MRIプロトコル

光遺伝学機能MRI

てんかんの臨床レビューのための脳波と機能的磁気共鳴画像の同時診断のための機器のセットアップとアーチファクト除去

疑わしい心臓血栓の評価のための心臓磁気共鳴:従来技術と新興技術

同時脳波と機能MRIにおける脳波データの確実な取得

7.0テスラにおける多発性硬化症の磁気共鳴画像

Clinical Indications for Rapid Sequence MRI in Pediatric Neurosurgical Patients and the Limitations and Barriers to Implementation

磁気共鳴画像法

インプラントの適合性とパルスシーケンスの脆弱性を評価するためにインプラントの金属による MRI アーチファクトの評価のためのプロトコル