Relationship between regional perfusion and oxygenation in patients with coronary artery disease (2009)

&lt;sec&gt;&lt;st&gt;Introduction&lt;/st&gt; Elevated deoxyhaemoglobin seen downstream in a territory subtended by a stenotic coronary artery can be assessed by blood oxygen level-dependent &amp;lpar;BOLD&amp;rpar; magnetic resonance imaging &amp;lpar;MRI&amp;rpar;. Previous animal studies have used a T2-prepared steady-state free-precession sequence to determine the BOLD signal in the myocardium. In theory, implementation of this sequence at the higher field strength of 3 Tesla &amp;lpar;T&amp;rpar; with the expected increase in signal-to-noise and contrast-to noise ratios, would further improve the detection of BOLD signal intensity &amp;lpar;SI&amp;rpar; changes. We sought to apply this method at 3T in patients with documented coronary artery disease and study the relationship between perfusion measurements by positron emission tomography &amp;lpar;PET&amp;rpar; and the BOLD signal. &lt;fig loc="float" id="HRT95S1htjun09toc2ab25f01"&gt;&lt;no&gt;Abstract 025 Figure.&lt;/no&gt;&lt;link locator="25-f01"&gt;&lt;/fig&gt; &lt;tbl id="HRT95S1htjun09toc2ab25t01" loc="float"&gt;&lt;no&gt;Abstract 025 Table&lt;/no&gt;&lt;tblbdy top-stubs="1"&gt;&lt;r&gt;&lt;c cspan="1" rspan="1"&gt;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;Stenosed N &amp;hairsp;&amp;equals;&amp;hairsp; 59&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;Remote N &amp;hairsp;&amp;equals;&amp;hairsp; 73&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;Nornal N &amp;hairsp;&amp;equals;&amp;hairsp; 60&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;p Value&lt;/c&gt;&lt;/r&gt;&lt;r&gt;&lt;c cspan="1" rspan="1"&gt;Rest MBF corrected &amp;lpar;ml/min/g/ &amp;lpar;mm Hg.bpm/104&amp;rpar;&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;1.43 ± 0.05 &amp;lpar;1.34 to 1.52&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;1.42 ± 0.04 &amp;lpar;1.34 to 1.51&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;1.39 ± 0.04 &amp;lpar;1.31 to 1.46&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;0.76&lt;/c&gt;&lt;/r&gt;&lt;r&gt;&lt;c cspan="1" rspan="1"&gt;Hyperaemic MBF &amp;lpar;ml/min/g&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;2.11 &amp;lpar;1.66 to 2.42&amp;rpar;*‡&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;2.73 &amp;lpar;2.16 to 3.44&amp;rpar;†&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;3.69 &amp;lpar;3.16 to 4.61&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;&lt;0.001&lt;/c&gt;&lt;/r&gt;&lt;r&gt;&lt;c cspan="1" rspan="1"&gt;BOLD SI change &amp;lpar;&amp;percnt;&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;1.25 &amp;lpar;−2.38 to 7.89&amp;rpar;*‡&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;8.91 &amp;lpar;4.95 to 12.78&amp;rpar;†&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;14.08 &amp;lpar;9.23 to 22.20&amp;rpar;&lt;/c&gt;&lt;c cspan="1" rspan="1"&gt;&lt;0.001&lt;/c&gt;&lt;/r&gt;&lt;/tblbdy&gt;&lt;tblfn id="nt111"&gt; Data are presented as means ± SD &amp;lpar;95&amp;percnt; CI&amp;rpar; or median &amp;lpar;interquartile range&amp;rpar; as appropriate. *p&lt;0.05 for comparison between stenosed and remote segments; †p&lt;0.05 for comparison between remote to ischemia and normal segments; ‡p&lt;0.05 for comparison between stenosed and normal segments. BOLD, blood oxygen level-dependent; MBF, myocardial blood flow; SI, signal intensity. &lt;/tblfn&gt;&lt;/tbl&gt; &lt;/sec&gt;&lt;sec&gt;&lt;st&gt;Methods&lt;/st&gt; Twenty-two patients &amp;lpar;aged 62 ± 8 years, 16 men&amp;rpar; with coronary artery disease &amp;lpar;at least one stenosis &gt;50&amp;percnt; on quantitative coronary angiography&amp;rpar; and 10 normal volunteers &amp;lpar;aged 52 ± 7 years, seven men&amp;rpar; underwent 3T BOLD MRI and PET. For BOLD MRI a midventricular slice was acquired every 30 s at rest and during adenosine stress &amp;lpar;140 μg/kg per minute&amp;rpar;. A set of six images was acquired at rest and at peak stress. Using PET with oxygen 15-labelled water, myocardial blood flow &amp;lpar;MBF&amp;rpar; was measured at baseline and during adenosine hyperaemia. The BOLD short-axis view was divided into six segments, according to the midventricular segments of the 17-AHA segment model, and mean SI were calculated using QMass &amp;lpar;Medis&amp;rpar; software. PET images were analysed with MATLAB software &amp;lpar;MathWorks Inc&amp;rpar; and registered with the BOLD short-axis image using anatomical landmarks. &lt;/sec&gt;&lt;sec&gt;&lt;st&gt;Results&lt;/st&gt; Based on the coronary anatomy, 59 myocardial segments were supplied by significantly stenosed vessels &amp;lpar;stenosed segments&amp;rpar; and 73 segments were supplied by vessels with minimal or no disease &amp;lpar;remote to ischaemia segments&amp;rpar;. A third group of myocardial segments &amp;lpar;n &amp;hairsp;&amp;equals;&amp;hairsp; 60&amp;rpar; from normal volunteers was labelled as “normal” segments. Rest MBF &amp;lpar;corrected for rate pressure product&amp;rpar;, stress MBF and BOLD SI change of stenosed, remote to ischaemia and normal segments are shown in the table. Taking quantitative coronary angiography as the gold standard, cut-off values for stress MBF &amp;lpar;&amp;les;2.45 ml/min per gram; area under the curve &amp;lpar;AUC&amp;rpar; 0.83&amp;rpar; and BOLD SI change &amp;lpar;&amp;les;3.74&amp;percnt;, AUC 0.78&amp;rpar; were determined to define ischaemic segments. BOLD MRI and PET agreed on the presence or absence of ischaemia in 18 of the 22 patients &amp;lpar;82&amp;percnt;&amp;rpar;, and in all normal subjects. With regard to per-segment analysis, taking PET as the gold standard and by applying the cut-off values for stress MBF and BOLD SI, BOLD MRI had moderate sensitivity &amp;lpar;63&amp;percnt;&amp;rpar; but very good specificity &amp;lpar;88&amp;percnt;&amp;rpar; for the identification of ischaemia. The fig shows an example of a patient with significant disease in the right coronary artery. &lt;/sec&gt;&lt;sec&gt;&lt;st&gt;Conclusions&lt;/st&gt; T2-prepared steady-state free-precession 3T BOLD imaging is feasible in the clinical setting and shows good agreement with PET perfusion measurements for the detection of myocardial ischaemia. &lt;/sec&gt;