A case of stunned myocardium determined by nuclear cardiac imaging

A 75 year old woman with acute chest pain was diagnosed as unstable angina. Anterior akinesis of left ventricule and small anterior perfusion defect were found by 99mTc blood pool imaging and 201Tl myocardial imaging. Coronary arteriography showed no organic stenosis, though anterior akinesis was still continued. Furthermore this akinesis and perfusion defect by 201Tl were all disappeared two weeks later. Thus, we determined this case as a stunned myocardium followed by severe angina with transient coronary obstruction.     

Examining a canine model of stunned myocardium with Gd-DTPA-enhanced MRI.

It has previously been shown that the distribution volume of Gd-DTPA (lambda) in infarcted, canine myocardium is higher than that of normal tissue. The purpose of this study was to determine whether stunned myocardium exhibits increased lambda. Stunning was produced in beagles by means of 30 min LAD occlusion followed by 3 weeks (n = 4) reperfusion. Gd-DTPA was infused at each imaging session and lambda determined in vivo using a saturation recovery turboFLASH sequence; cine imaging was used to assess ventricular wall thickening (%WT). (201)Tl uptake was used as an independent assessment of viability. %WT data confirmed that the brief insult caused prolonged, yet reversible, regional contractile dysfunction in each animal. %WT was not significantly different from baseline values by 3 weeks post-reflow. Normal (201)Tl uptake confirmed the absence of infarction. The lambda of stunned tissue (lambda = 0.381 +/- 0.030 ml/g) was not elevated above that of normal tissue (lambda = 0.398 +/- 0.027 ml/g, P = NS), at any time point studied, in vivo. These data suggest that an increase in lambda is a specific indicator of irreversible damage.     

Management of patients with stunned myocardium associated with subarachnoid hemorrhage

Cardiac complications are well known after aneurysmal subarachnoid hemorrhage. Electrocardiographic changes occur in 50% to 100% of such cases. Arrhythmias, left ventricular dysfunction, and frank myocardial infarction are infrequently observed. Myocardial infarction must be differentiated from neurogenic stunned myocardium, which is a reversible condition. From 1996 to 2001, 105 patients with aneurysmal subarachnoid hemorrhage underwent endovascular treatment at the University of Michigan. Of these, four patients with no history of cardiac disease experienced cardiac failure related to neurogenic stunned myocardium. All had signs of left ventricular dysfunction, electrocardiographic changes, and elevated cardiac enzymes. Three had pulmonary edema at presentation. All were diagnosed with myocardial infarction. One underwent coronary angiography, which was normal. All were considered poor surgical candidates and underwent endovascular treatment of the aneurysms. Three of four patients developed symptomatic vasospasm, and two required balloon angioplasty. Three patients achieved good outcomes. The eldest died from severe vasospasm that was unresponsive to angioplasty. Reversible cardiac failure associated with subarachnoid hemorrhage may be due the neurogenic stunned myocardium. Frequent symptomatic vasospasm occurs, possibly related to poor cardiac output and the inability to optimize hyperdynamic hypervolemic therapy, particularly with compromised volume status. These patients can be treated with endovascular therapy of the aneurysms and balloon angioplasty as needed. With aggressive management, patients can recover from these reversible cardiac complications.     

Visualization of atrial myocardium with Tl-201: case report

A case of right atrial visualization on Tl-201 imaging in a patient with marked right atrial enlargement secondary to atrial septal defect is described. The misinterpretation of Tl-201 an gated cardiac studies on initial inspection, due to this unusual finding, and the importance of obtaining special lateral and oblique view for correct identification of cardiac chambers are discussed.     

Visualization of atrial myocardium with thallium-201: case report.

An adult patient evaluated for cyanotic congenital heart disease was found to have pulmonary atresia with intact ventricular septum, hypoplastic right ventricle, and right atrial enlargement. Thallium-201 myocardial imaging before surgical correction showed thallium activity in the right atrium. Following the establishment of a conduit from the right atrium to pulmonary artery, the right-atrial thallium uptake was even more prominent.     

Neurogenic stunned myocardium after embolization in two children with vein of Galen aneurysmal malformation

Introduction

This study reports the first cases of neurogenic stunned myocardium in two children with vein of Galen aneurysmal malformation after interventional treatment.

Patients

Two newborns with vein of Galen aneurysmal malformation and high output cardiac failure developed a severe reversible left ventricular dysfunction shortly after embolization, concurrently with acute hydrocephalus.

Results

There was a resolution of the cardiac symptoms of left ventricular dysfunction within a few days under treatment with milrinone and dobutamine.

Conclusions

Reversible left ventricular dysfunction is observed in adult patients mainly after subarachnoid hemorrhage and is called neurogenic stunned myocardium (NSM). Other forms of brain injuries have also been identified accounting for this condition in adults. In pediatric population especially with specific cerebral diseases, NSM may be underdiagnosed.     

Detection of stunned myocardium in post-reperfusion cases of acute myocardial infarction

OBJECTIVE: This study was designed to evaluate the correlation between improvements in serial images obtained by SPECT imaging with Tc-99m MIBI (MIBI) and I-123 BMIPP (BMIPP) and the recovery of cardiac function in acute myocardial infarction (AMI) patients after reperfusion therapy. METHODS: Twenty five patients who were admitted to the emergency room within 24 hours after the onset of the first event of AMI were enrolled in this study. The culprit coronary arteries were identified by CAG and were treated with direct percutaneous transluminal coronary angiography (PTCA), followed by stent implantation. To determine risk areas, initial image at the onset was acquired by the freeze method, in which MIBI was injected before the treatment and the image was collected after the reperfusion therapy. After the reperfusion treatment was completed, MIBI SPECT images at rest were performed on days 7 and 60. Both early and late images, including gated SPECT images were acquired after 30-60 minutes and 6 hours post injection, respectively. In addition, BMIPP SPECT images at rest were obtained 30 minutes after injection of 148 MBq BMIPP on days 7 and 60 (BMIPP image). The obtained image was divided into 48 segments and percent uptake of each segment was calculated. The number of abnormal areas (NAA) was defined as the segment with a % uptake less than 60% of normal uptake, and the change of NAA over time was evaluated. RESULTS: The NAA on the MIBI-early image significantly improved between thepre image and the day 7 image (p < 0.001), but no similar improvement was observed between day 7 and day 60. On the other hand, the NAA of the MIBI-delayed image did not significantly improve up to day 7, but a slight improvement was observed on days 7 and 60 (p < 0.05). A significant improvement in the NAA of the BMIPP image was observed between day 7 and day 60, as shown in the delayed image (p < 0.05). An excellent correlation on the NAA between the MIBI-delayed image and the BMIPP image was observed with r = 0.983 (p < 0.001) at day 7 and r = 0.984 (p < 0.001) at day 60 resulting in a consistent diagnosis. Analysis of the myocardial function by means of gated SPECT indicated that the wall motion significantly improved as the myocardial perfusion improved up to day 7 and thereafter a steady improvement was observed up to day 60. The improvement in the NAA in MIBI-delayed images in the subacute phase (day 7) and in the chronic phase (day 60) as well as BMIPP images showed excellent correlation with the improvement in RWM and RWT (MIBI-delayed image: r = 0.550 (RWM), r = 0.647 (RWT)), (BMIPP image: r = 0.536 (RWM), r = 0.565 (RWT)). CONCLUSION: We conclude that insufficient ATP production caused by mitochondrial dysfunction in stunned myocardium is closely related to MIBI delayed and BMIPP image Furthermore, MIBI delayed imaging as well as BMIPP imaging will provide a clue to the state of stunned myocardium after reperfusion therapy in patients with AMI.     

Incidence of stunned, hibernating and scarred myocardium in ischaemic cardiomyopathy

Purpose Different criteria to identify residual viability in chronically dysfunctioning myocardium in patients with coronary artery disease (CAD) can be derived by the combined assessment of myocardial blood flow (MBF) and glucose utilisation (MRG) using positron emission tomography (PET). The aim of this study was to evaluate, in a large number of patients, the prevalence of these different patterns by purely quantitative means.Methods One hundred and sixteen consecutive patients with ischaemic cardiomyopathy (LVEF 40%) underwent resting 2D echocardiography to assess regional contractile function (16-segment model). PET with ¹⁵O-labelled water (H₂¹⁵O) and ¹⁸F-fluorodeoxyglucose (FDG) was used to quantify MBF and MRG during hyperinsulinaemic euglycaemic clamp. Dysfunctional segments with normal MBF (0.6 ml min^–1 g^–1) were classified as stunned, and segments with reduced MBF (<0.6 ml min^–1 g^–1) as hibernating if MRG was 0.25 mol min^–1 g^–1. Segments with reduced MBF and MRG <0.20 mol min^–1 g^–1 were classified as transmural scars and segments with reduced MBF and MRG between 0.20 and 0.25 mol min^–1 g^–1 as non-transmural scars.Results Eight hundred and thirty-four (46%) segments were dysfunctional. Of these, 601 (72%) were chronically stunned, with 368 (61%) having normal MRG (0.47±0.20 mol min^–1 g^–1) and 233 (39%) reduced MRG (0.16±0.05 mol min^–1 g^–1). Seventy-four (9%) segments with reduced MBF had preserved MRG (0.40±0.18 mol min^–1 g^–1) and were classified as hibernating myocardium. In addition, 15% of segments were classified as transmural and 4% as non-transmural scar. The mean MBF was highest in stunned myocardium (0.95±0.32 ml min^–1 g^–1), intermediate in hibernating myocardium and non-transmural scars (0.47±0.09 ml min^–1 g^–1 and 0.48±0.08 ml min^–1 g^–1, respectively), and lowest in transmural scars (0.40±0.14 ml min^–1 g^–1, P<0.01). MRG was comparable in hibernating and stunned myocardium with preserved MRG (0.40±0.19 mol min^–1 g^–1 vs 0.46±0.20 mol min^–1 g^–1, NS), and lowest in stunned myocardium with reduced MRG and transmural scars.Conclusion Chronic stunning is more prevalent than expected. The degree of MRG reduction in stunned myocardium may disclose segments at higher risk of permanent damage.     

Contrast-enhanced MR delineation of stunned myocardium with administration of MnCl(2) in rats

PURPOSE: To determine whether stunned myocardium can be delineated at magnetic resonance (MR) imaging with differential cellular uptake of manganese ions. MATERIALS AND METHODS: Twenty-one adult Sprague-Dawley rats underwent either (a) a sequence of three episodes of 10 minutes of coronary artery occlusion and 12 minutes of reflow (group 1, n = 9); (b) a single episode of 10 minutes of occlusion followed by reflow (group 2, n = 6), designed to produce different degrees of myocardial stunning; or (c) a single episode of 2 minutes of occlusion followed by reperfusion (group 3, n = 6), designed to produce no stunning. Ventricular wall thickening was measured on spin-echo (SE) MR images. MnCl2 (0.025 mmol/kg) was intravenously infused for 10 minutes. Highly T1-sensitive inversion-recovery (IR) SE images were obtained to detect subtle regional differences in manganese accumulation. Hearts were stained at sacrifice to define area at risk and to test for myocardial infarction. Significance of differences in mean values was evaluated with repeated-measures analysis of variance. RESULTS: All hearts were free of infarction, as detected with triphenyltetrazolium chloride staining. On IR SE images, the hearts from rats in groups 1 and 2 exhibited clearly delineated regions of diminished manganese uptake in the expected territory of the occluded artery. The circumferential extent of the manganese-defined defect (45.5% +/- 5.6) was similar to that of the area at risk (46.8% +/- 7.5). Systolic wall thickening in the defect was significantly (P <.01) less than in the nonischemic myocardium (2.7% +/- 3.3 vs 31.2% +/- 7.5 and 10.0% +/- 4.8 vs 28.6% +/- 6.5, respectively, for groups 1 and 2). The hearts from rats in group 3 demonstrated no wall thickening deficit or abnormal zone on manganese-enhanced images. CONCLUSION: Stunned myocardium was delineated with MnCl2-enhanced MR imaging as a hypoenhanced zone. This finding suggests that Ca2+ channel activity is diminished in stunned myocardium.     

Dynamic changes in cardiac fatty acid metabolism in the stunned human myocardium

BACKGROUND: The chronological changes or mechanisms in cardiac fatty acid metabolism under clinical conditions of hypoxia and ischemia have not been fully elucidated. 123-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) can be used with single photon emission computed tomography (SPECT) to evaluate myocardial fatty acid metabolism. We investigated chronological changes in energy metabolism in the stunned human myocardium by means of 123I-BMIPP myocardial SPECT. METHODS AND RESULTS: We conducted 123I-BMIPP myocardial SPECT in 10 patients with stunned myocardium during the acute, subacute and chronic phases after onset. The left ventricle was divided into 9 regions on SPECT, and the degree of abnormalities in each region was scored in four grades from normal (0) to defect (4). We also examined wash-out rates on BMIPP images. The scores on early BMIPP images in the acute, subacute and chronic phases were 5.6 +/- 1.8, 13.4 +/- 3.5 and 2.5 +/- 1.1, respectively, and the score was highest in the subacute phase (p < 0.001). Similarly, scores on the late images were 2.3 +/- 1.7, 18.3 +/- 4.5 and 4.7 +/- 2.6, respectively, and highest in the subacute phase (p < 0.001). The wash-out rates (normal: 18.2 +/- 2.1%) in the acute, subacute and chronic phases were 12.1 +/- 4.8%, 44.9 +/- 10.0% and 23.1 +/- 4.6%, respectively, with the value being lowest during the acute phase (p < 0.05), and highest during the subacute phase (p < 0.001). CONCLUSION: These results suggested that fatty acid metabolism in the stunned human myocardium changes dynamically over time.     

Ribose facilitates thallium-201 redistribution in patients with coronary artery disease

To investigate whether i.v. infusion of ribose, an adenine nucleotide precursor, postischemia facilitates thallium-201 (201Tl) redistribution and improves identification of ischemic myocardium in patients with coronary artery disease (CAD), 17 patients underwent two exercise 201Tl stress tests, performed 1-2 wk apart. After immediate postexercise planar imaging, patients received either i.v. ribose (3.3 mg/kg/min x 30 min) or saline as a control. Additional imaging was performed 1 and 4 hr postexercise. Reversible defects were identified by count-profile analysis. Significantly more (nearly twice as many) reversible 201Tl defects were identified on the post-ribose images compared to the post-saline (control) images at both 1 and 4 hr postexercise (p less than 0.001). Quantitative analyses of the coronary arteriogram was available in 13 patients and confirmed that the additional reversible defects were in myocardial regions supplied by stenosed arteries. We conclude that ribose appears to facilitate 201Tl redistribution in patients with CAD and enhances identification of ischemic myocardium.     

Quantification of severity and redistribution of ischemic and infarcted myocardium by Thallium-201 polar map: evaluation in patients with single vessel disease

Quantitative analysis of the polar map obtained from T1-201 single photon emission computed tomogram was employed to assess regional myocardial viability in 66 patients with single vessel coronary artery disease and 16 control subjects. Counts of region of interest in the stenotic and infarcted lesions and normal reference areas were calculated on the polar map. Severity of hypoperfused myocardium was determined as initial percent uptake (%Ui) and delayed percent uptake (%Ud). Redistribution was analyzed as a ratio of %Ud to %Ui (%Ud/%Ui). In the control group, the average %Ui was 85.8 +/- 9.4 and %Ud/%Ui was 1.03 +/- 0.04. Twenty five with reversible defect showed reduced %Ui (51.5 +/- 13.3) and increased %Ud/%Ui (1.37 +/- 0.26). Forty one cases with non-reversible defect were divided into two groups according to the value of %Ui. In the first group with a high %Ui (n = 17), the average %Ui was 74.5 +/- 4.7 and %Ud/Ui was in normal range (1.06 +/- 0.06). In the second group (n = 24), %Ui was most reduced (31.7 +/- 8.7), although %Ud/%Ui was in normal range (1.05 +/- 0.17). No significant correlation was shown between %Ui and %Ud/%Ui in the two groups with non-reversible defect. Correlation between %Ui and %Ud/%Ui was high (r = -0.76) in the group of reversible defect and the group of non-reversible defect with minimal reduced %Ui. It is concluded that the quantitative criteria obtained from polar map is valid to assess regional myocardial viability. The quantitative imaging data were also compared with coronary angiographic and left ventriculographic data.     

Transverse CAT of the myocardium with 201 Tl

A new computerized axial tomographic (CAT) scanner (J&P Tomoscanner) which enables the transverse section viewing of any organ labelled by one of the monophotonic gamma-ray emitting tracers commonly used in Nuclear Medicine, has been recently commercialized. Its abilities in visualising the 201 Tl labelled myocardium are evaluated with normal hearts and patients with documented infarctions. Positive results have been obtained, allowing an interesting approach to the estimation of the anatomical extent of necrosis.     

Rapid redistribution of thallium-201 post stress testing in a patient with variant angina.

Reperfusion of an ischemic area after stress scanning with 201TI can occur rapidly and early scanning post stress testing is emphasized.     

^123I—BMIPP在犬顿抑心肌中的摄取、清除和代谢

目的利用123I-15对碘苯基-3(R，S)甲基十五烷酸(BMIPP)在犬顿抑心肌(SM)中的不匹配分布，探讨其作为诊断SM示踪剂的可能性。方法建立标准犬左回旋支(LCX)顿抑心肌模型(18min结扎后再灌注，n=12)。监测血流动力学和心功能参数。Doppler探头测量ICX血流和局部室壁收缩厚度(WT)。SPEGT显像和组织γ计数法测量局部心肌的BMIPP、201Tl分布和微球灌注(RBF)。测量局部心肌耗氧量、葡萄糖和乳糖利用率。动态测量局部BMIPP摄取与清除。薄层层析法分析BMIPP及其代谢产物。结果心肌顿抑时的血流动力学参数和冠状动脉血流恢复到基础水平，但WT明显低于基础值[(12.9±29.1)％和(66.3±22.4)％，P＜0.01]。离体心脏SPECT显像示，顿抑心肌残留BMIPP[(70±6)％]高于201Tl[(66±6)％，P＜0.05]。SM组织计数则BMIPP[(88.5±6.0)％]和Tl[(85.4±6.7)％]高于RBF[(70.4±10.5)％，P＜0.001]。SM中，201Tl与RBF相关性较好(r=0.67)，而BMIPP与RBF不相关(r=0.11)。虽然SM的局部耗氧量和乳糖利用率低于基础值，但BMIPP代谢产物清除增加。未经代谢的BMIPP摄取和清除均有减低趋势。结论代谢因素对SM的BMIPP残留有明显影响，主要表现为BMIPP摄取减低和其代谢产物清除增加。     

~(123)I-BMIPP在犬顿抑心肌中的摄取、清除和代谢

目的　利用12 3 I 15对碘苯基 3(R ,S)甲基十五烷酸 (BMIPP)在犬顿抑心肌 (SM)中的不匹配分布 ,探讨其作为诊断SM示踪剂的可能性。方法　建立标准犬左回旋支 (LCX)顿抑心肌模型(18min结扎后再灌注 ,n =12 )。监测血流动力学和心功能参数。Doppler探头测量LCX血流和局部室壁收缩厚度 (WT)。SPECT显像和组织γ计数法测量局部心肌的BMIPP、2 0 1Tl分布和微球灌注(RBF)。测量局部心肌耗氧量、葡萄糖和乳糖利用率。动态测量局部BMIPP摄取与清除。薄层层析法分析BMIPP及其代谢产物。结果　心肌顿抑时的血流动力学参数和冠状动脉血流恢复到基础水平 ,但WT明显低于基础值 [(12 .9± 2 9.1) %和 (6 6 .3± 2 2 .4) % ,P <0 .0 1]。离体心脏SPECT显像示 ,顿抑心肌残留BMIPP[(70± 6 ) % ]高于2 0 1Tl[(6 6± 6 ) % ,P <0 .0 5 ]。SM组织计数则BMIPP[(88 5±6 0 ) % ]和Tl[(85 .4± 6 .7) % ]高于RBF[(70 .4± 10 .5 ) % ,P <0 .0 0 1]。SM中 ,2 0 1Tl与RBF相关性较好(r=0 .6 7) ,而BMIPP与RBF不相关 (r=0 .11)。虽然SM的局部耗氧量和乳糖利用率低于基础值 ,但BMIPP代谢产物清除增加。未经代谢的BMIPP摄取和清除均有减低趋势。结论　代谢因素对SM的BMIPP残留有明显影响 ,主要表现为BMIPP摄取减低和其代谢产物清除