Title: Gadolinium - To Use or Not Use?<br/>Author: WanTsu Wendy Chang<br/><a href='http://umem.org/profiles/faculty/1322/'>[Click to email author]</a><hr/><p>
         </p>
<p>
        <strong>Gadolinium - To Use or Not Use?</strong></p>
<ul>
        <li>
                One advantage of MR imaging is the option between non-contrast vs. contrast-enhanced MR angiography (MRA) and venography (MRV)</li>
        <li>
                How do they work and when should you use which?</li>
</ul>
<p>
         </p>
<table align="center" border="1" cellpadding="1" cellspacing="1" style="width: 500px">
        <tbody>
                <tr>
                        <td>
                                 </td>
                        <td>
                                <strong>Non-Contrast MRA/MRV</strong></td>
                        <td>
                                <strong>Contrast-Enhanced MRA/MRV</strong></td>
                </tr>
                <tr>
                        <td style="width: 150px;">
                                <strong>How Does It Work?</strong></td>
                        <td style="width: 200px;">
                                <p>
                                        * Time-of-flight (TOF) is a commonly used sequence</p>
                                <p>
                                        * Relies on flow of blood into imaging plane</p>
                                <p>
                                        * Difference between signal of blood and suppressed background tissue</p>
                        </td>
                        <td style="width: 200px;">
                                <p>
                                        * Similar to CT angiography/venography</p>
                                <p>
                                        * Higher intravascular signal purely from gadolinium-based contrast, not dependent on flow</p>
                                <p>
                                         </p>
                        </td>
                </tr>
                <tr>
                        <td>
                                <strong>Pros</strong></td>
                        <td>
                                <p>
                                        * Does not require contrast</p>
                                <p>
                                         </p>
                        </td>
                        <td>
                                <p>
                                        * Generally better image quality</p>
                                <p>
                                        * Shorter acquisition time</p>
                        </td>
                </tr>
                <tr>
                        <td>
                                <strong>Cons</strong></td>
                        <td>
                                <p>
                                        * Slow, turbulent, or retrograde flow may result in signal loss</p>
                                <p>
                                        * Over-estimates stenosis</p>
                                <p>
                                        * Longer acquisition time</p>
                        </td>
                        <td>
                                <p>
                                        * RIsks associated with contrast use</p>
                                <p>
                                        * Timing of image acquisition important</p>
                        </td>
                </tr>
                <tr>
                        <td>
                                <strong>Applications</strong></td>
                        <td>
                                <p>
                                        * Patients with allergy to gadolinium, renal dysfunction, pregnancy</p>
                                <p>
                                        * Evaluation of intracranial vessels and cerebral venous system</p>
                        </td>
                        <td>
                                <p>
                                        * Evaluation of stenoses and occlusions of the neck vessels and their origins at the aortic arch</p>
                                <p>
                                         </p>
                                <p>
                                         </p>
                        </td>
                </tr>
        </tbody>
</table>
<p>
         </p>
<fieldset><legend>References</legend>

                <p style="text-align: center;">
        <em><strong>Follow me on Twitter @ EM_NCC</strong></em></p>
</fieldset>