Prognostic value of myocardial perfusion imaging performed pre-renal transplantation: post-transplantation follow-up and outcomes

Purpose

Noninvasive stress testing is commonly performed as part of pre-renal transplantation (RT) evaluation. We evaluated the prognostic value of myocardial perfusion imaging (MPI)—myocardial perfusion, left ventricular ejection fraction (LVEF) and heart rate response (HRR)—post-RT.

Methods

Consecutive RT recipients were identified at our institution. MPI was considered abnormal when there was a perfusion defect or reduced ejection fraction. HRR to vasodilator stress was calculated as percentage change from baseline. The primary outcome was a composite of cardiovascular (CV) death, myocardial infarction (MI) and coronary revascularization (CR) post-RT; all-cause mortality was the secondary endpoint.

Results

Among 1189 RT recipients, 819 (69%) underwent MPI. Of those, 182 (22%) had abnormal MPI, and 31 (4%) underwent CR pre-RT. During a median follow-up of 56 months post-RT, the annual CV event and mortality rates for patients who had no MPI, normal MPI and abnormal MPI were 1.5%, 3.1% and 4.3% (p?<?0.001), and 1.8%, 2.6% and 3.6% (p?=?0.016), respectively. After multivariate adjustment, compared to patients without MPI, the hazard ratios (HRs) for CV events for normal and abnormal MPI were 1.47 ([0.93–2.33], p?=?0.1) and 1.78 ([1.03–3.06], p?=?0.04). Blunted HRR was an independent predictor of CV events (HR?=?1.73 [1.04–2.86], p?=?0.034) and all-cause death (HR?=?2.26 [1.28–3.98], p?=?0.005) after adjusting for abnormal MPI. Patients with abnormal MPI who underwent CR pre-RT had annual mortality rates similar to those with no or normal MPI (1.9% vs. 1.7–2.6%, p?=?0.2), while those who did not undergo CR had higher annual mortality (4% vs. 1.7–2.6%, p?=?0.003).

Conclusions

One in five RT recipients who underwent screening MPI had an abnormal study, an independent predictor of CV events. A blunted HRR to vasodilator stress was associated with increased risk of CV events and death, even after adjusting for abnormal MPI. Patients with abnormal MPI who underwent CR were at low risk of mortality following RT. MPI is a useful tool to aid in risk stratification pre-RT.

     

Prognostic value of stress 99mTc-tetrofosmin myocardial perfusion imaging in predicting all-cause mortality: a 6-year follow-up study

Purpose The aim of this study was to ascertain whether stress myocardial perfusion imaging can independently predict long-term mortality.Methods We studied 1,386 patients with known or suspected coronary artery disease by means of stress ^99mTc-tetrofosmin myocardial perfusion tomography. The end point during follow-up was death from any cause. Mortality rates were compared with that in a reference population using calculated age- and gender-specific data in the general population.Results Mean age was 60±11 years. There were 608 (44%) women. Perfusion abnormalities were fixed in 416 (30%) patients and reversible in 445 (32%) patients. During a mean follow-up of 6±1.9 years, 290 (21%) patients died. The annual mortality was 1.7% in patients with normal perfusion and 5.2% in patients with abnormal perfusion. Patients with multivessel distribution of perfusion abnormalities had the highest annual mortality (6.2%). The annual mortality in the reference population was 3.2%. In a multivariate analysis model, predictors of death were age [risk ratio (RR)=1.06, 95% CI 1.04–1.07], male gender (RR=2, CI 1.6–2.6), history of heart failure (RR=2.3, CI 1.8–3.1), diabetes mellitus (RR=2.1, CI 1.6–2.7), smoking (RR=1.8, CI 1.4–2.3), reversible perfusion defects (RR=1.8, CI 1.4–2.5) and fixed perfusion defects (RR=1.7, CI 1.3–2.1).Conclusion Myocardial perfusion abnormalities on stress ^99mTc-tetrofosmin tomography are independently associated with long-term risk of death. The extent of perfusion abnormalities is a major determinant of mortality. The presence of normal perfusion is associated with a lower mortality compared with the general population.     

Prognostic value of quantitative high-speed myocardial perfusion imaging

Background

We studied the prognostic value of fully automated quantitative analysis software applied to new solid-state, high-speed (HS) SPECT-myocardial perfusion imaging (MPI).

Methods

1,613 consecutive patients undergoing exercise or adenosine HS-MPI were followed for 2.6?±?0.5?years for all-cause mortality (ACM). Automated quantitative software was used to compute stress total perfusion deficit (sTPD) and was compared to semi-quantitative visual analysis. MPI was characterized as 0% (normal), 1%-4% (minimal perfusion defect), 5%-10% (mildly abnormal), and >10% (moderately/severely abnormal).

Results

During follow-up, 79 patients died (4.9%). Annualized ACM increased with progressively increasing sTPD; 0% (0.87%), 1%-4% (1.94%), 5%-10% (3.10%), and >10% (5.33%) (log-rank P?<?.0001). While similar overall findings were observed with visual analysis, only sTPD demonstrated increased risk in patients with minimal perfusion defects. In multivariable analysis, sTPD?>?10% was a mortality predictor (HR 3.03, 95% CI 1.30-7.09, P?=?.01). Adjusted mortality rate was substantial in adenosine MPI, but low in exercise MPI (9.0% vs 1.0%, P?<?.0001).

Conclusions

By quantitative analysis, ACM increases with increasing perfusion abnormality among patients undergoing stress HS-MPI. These findings confirm previous results obtained with visual analysis using conventional Anger camera imaging systems.     

中枢神经系统原发淋巴瘤和高级别星形细胞瘤MR灌注成像的对比研究

目的 探讨MR灌注成像鉴别中枢神经系统原发淋巴瘤(PCNSL)和高级别星形细胞瘤的价值.方法 PCNSL患者12例,高级别星形细胞肿瘤患者23例,手术前行常规MR检查及MR灌注检查,比较其MR灌注伪彩图像和灌注曲线,测量肿瘤实质部分最大相对脑血容量(rCBV),将所测量数值进行t检验.结果 PCNSL实质部分rCBV平均为1.8±0.5;高级别星形细胞瘤实质部分rCBV平均为3.9±0.9,二者之间差异有统计学意义(P<0.05).PCNSL实质区域时间-信号曲线对比剂首过后曲线逐渐接近基线,12例中有7例超过基线水平.高级别星形细胞瘤实质区域时间-信号曲线对比剂首过后曲线逐渐向基线水平靠拢,但均不能完全恢复到基线水平.结论 MR灌注成像有助于鉴别PCNSL和高级别星形细胞瘤.     

MR imaging after aneurysmal subarachnoid hemorrhage and surgery: a long-term follow-up study.

BACKGROUND AND PURPOSE: We assumed that patients with surgically treated aneurysmal subarachnoid hemorrhage (SAH) might have more lesions than those revealed by CT that could be visible on MR images. METHODS: We conducted a retrospective study of a series of 147 patients with aneurysmal SAH who were treated surgically within 3 days of the onset of SAH. One hundred four patients (mean age, 48.8 years) underwent MR imaging studies 2.1 to 5.6 years (mean, 3.3 years) postoperatively. RESULTS: Eighty-four (81%) patients presented a total of 152 areas of increased signal intensity on T2-weighted images, consistent with infarction; 48% of the patients had lesions in the frontal lobes. CT performed 3 months postoperatively revealed hypodense areas on the scans of only 57% of the patients and showed lesions in the frontal lobes of only 16% of the patients. CONCLUSION: Patients who undergo early surgery for aneurysmal SAH have more lesions than are revealed by CT. The difference is remarkable, especially in the frontal lobes.     

Comparison between CT and MR in perfusion imaging assessment of high-grade gliomas

Purpose

The aim of our study was to compare the relative cerebral blood volume (CBV) values obtained by first-pass dynamic susceptibility-weighted contrast-enhanced (DSC) T2-weighted magnetic resonance (MR) and perfusion computed tomography (P-CT) imaging in high-grade gliomas (HGG) in the same patient population.

Materials and methods

Sixteen patients with histologically proven HGG underwent P-CT and DSC-MR brain imaging. P-CT studies were obtained using a four-row multislice CT scanner and postprocessed with a commercial software package based on a deconvolution-based technique. DSC-MR images were obtained at 1.5 T with a first-pass dynamic susceptibility contrast-enhanced T2-weighted sequence. P-CT and DSC-MR images were obtained within 4 days of each another, always before surgery. Maximum CBV ratios normalised with contralateral white matter (rCBV) were calculated. Statistical analysis was performed with the classical parametric statistic procedure.

Results

A linear correlation between maximum rCBV values obtained with P-CT and DSC-MR imaging was evident. The best linear model is CT=slope×MR+error and provides a highly significant estimate of the slope equal to 1.08. Thus CT results can be predicted from MR values. Therefore, it is also possible to predict MR results from CT values by estimating the linear model MR=slope×CT+error. DSC-MR imaging gave lower rCBV average values (4.92±1.52) compared with P-CT (5.56±1.55).

Conclusions

In our population of patients, P-CT and DSC-MR imaging showed proportional results in rCBV assessment of HGGs, and thus both modalities may be used interchangeably in HGG of the brain.     

MR imaging characteristics of protoplasmic astrocytomas

Introduction  

Protoplasmic astrocytomas are a poorly recognized and uncommon subtype of astrocytoma. While usually categorized with other low-grade gliomas, there is literature to suggest that protoplasmic astrocytomas have differences in biology compared to other gliomas in this group. This paper presents the MR imaging characteristics of a series of eight protoplasmic astrocytomas.     

MR imaging characteristics of pilomyxoid astrocytomas

BACKGROUND AND PURPOSE: Pilomyxoid astrocytoma (PMA) is a recently described tumor that typically occurs in the chiasmatic-hypothalamic region in young children and has unique histopathologic and clinical characteristics. These tumors have been previously diagnosed as pilocytic astrocytoma (PA). PMA appears to have a higher rate of recurrence and CSF dissemination than typical PA. METHODS: We analyzed MR findings in four patients with PMA and compared them with those of typical chiasmatic-hypothalamic PA. RESULTS: MR findings of PMA were chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity that extended into the deep white and gray matter, and CSF dissemination. CONCLUSION: Larger series are needed before the MR imaging findings of chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity extending into the deep white and gray matter, and CSF dissemination can be used in the differential diagnosis of such tumors.     

Prognostic value of preoperative dynamic contrast-enhanced MRI perfusion parameters for high-grade glioma patients

Introduction

The prognostic value of the dynamic contrast-enhanced (DCE) MRI perfusion and its histogram analysis-derived metrics is not well established for high-grade glioma (HGG) patients. The aim of this prospective study was to investigate DCE perfusion transfer coefficient (K^trans), vascular plasma volume fraction (v_p), extracellular volume fraction (v_e), reverse transfer constant (k_ep), and initial area under gadolinium concentration time curve (IAUGC) as predictors of progression-free (PFS) and overall survival (OS) in HGG patients.

Methods

Sixty-nine patients with suspected anaplastic astrocytoma or glioblastoma underwent preoperative DCE-MRI scans. DCE perfusion whole tumor region histogram parameters, clinical details, and PFS and OS data were obtained. Univariate, multivariate, and Kaplan–Meier survival analyses were conducted. Receiver operating characteristic (ROC) curve analysis was employed to identify perfusion parameters with the best differentiation performance.

Results

On univariate analysis, v_e and skewness of v_p had significant negative impacts, while k_ep had significant positive impact on OS (P < 0.05). v_e was also a negative predictor of PFS (P < 0.05). Patients with lower v_e and IAUGC had longer median PFS and OS on Kaplan–Meier analysis (P < 0.05). K^trans and v_e could also differentiate grade III from IV gliomas (area under the curve 0.819 and 0.791, respectively).

Conclusions

High v_e is a consistent predictor of worse PFS and OS in HGG glioma patients. v_p skewness and k_ep are also predictive for OS. K^trans and v_e demonstrated the best diagnostic performance for differentiating grade III from IV gliomas.

     

MR扩散加权成像鉴别脑结核瘤及高级星形细胞瘤和脑转移瘤的价值

目的探讨MR扩散加权成像（DWI）在脑结核瘤、高级星形细胞瘤和脑转移瘤鉴别诊断中的价值。方法14例脑结核瘤、15例脑高级星形细胞瘤和21例脑转移瘤患者，在术前或接受治疗前行常规MRI和DWI。测量并计算3种疾病瘤体、瘤周围水肿带的平均表观扩散系数（ADC）值和病灶与对侧相应部位正常脑白质区ADC值的比值（rADC值）。结果脑结核瘤瘤体平均ADC值和rADC值分别为（1．2±0．2）×10^-3mm^2·s^-1和1．6±0．3，高级星形细胞瘤瘤体平均ADC值和rADC值分别为（0．8±0．1）×10^-3mm^2·s^-1和1．1±0．1，转移瘤瘤体平均ADC值和rADC值分别为（0．8±0．1）×10^-3mm^2·s^-1和1．0±0．2。3种疾病瘤体平均ADC值（F=33．57，P〈0．01）之间和rADC值（F=33．27，P〈0．01）之间差异均有统计学意义。脑结核瘤瘤周水肿带平均ADC值和rADC值分别为（1．8±0．1）×10^-3mm^2·s^-1和2．5±0．2，脑高级星形细胞瘤瘤周水肿带平均ADC值和rADC值分别为（1．4±0．2）×10^-3mm^2·s^-1和1．8±0．3，脑转移瘤瘤周水肿带平均ADC值和rADC值分别为（1．9±0．2）×10^-3mm^2·s^-1和2．3±0．5。3种疾病瘤周围水肿带平均ADC值（F=23．17，P〈0．01）之间和rADC值（F=5．94，P〈0．01）之间差异均有统计学意义。结论结合MRI、DWI检测方法，根据病灶瘤体和瘤周水肿带的ADC和rADC值可帮助鉴别脑结核瘤、脑高级星形细胞瘤和脑转移瘤。     

Prognostic value of stress myocardial perfusion imaging in octogenarian population

BACKGROUND: The prognostic value of myocardial perfusion imaging (MPI) in the very elderly population has not been addressed specifically. The aim of this study was to examine the characteristics of the octogenarian population referred for MPI and the prognostic value of the procedure in terms of patient gender. METHODS: The study sample consisted of 162 consecutive patients (61 women, 101 men) of mean age 83 +/- 3 years (range, 80-90) who underwent stress MPI. The duration of follow-up was 45+/-12 months. Outcome measures were cardiac-related death, and nonfatal myocardial infarction (MI). RESULTS: Thirty-one major cardiac events (19%) were recorded, including 26 cardiac deaths and 5 MI events, in 6 of the 61 women (10%) and 25 of the 101 men (25%) (p < 0.03). The univariate predictors of cardiac death or MI, except of known coronary artery disease (CAD), were MPI variables: left ventricular (LV) dilatation, increased lung uptake, abnormal scan, and the presence and extent of myocardial ischemia. However, the only predictors for major cardiac events were: LV dilatation (OR = 6.9, 95% CI 2.7-17.4, p < 0.0001) and ischemia by scan (OR = 2.75, 95% CI 1.09-6.96, p < 0.03). The Kaplan Meier curve demonstrated significant differences in survival between patients with or without LV dilatation and patients with or without ischemia. CONCLUSIONS: LV dilatation and myocardial ischemia were useful predictors of cardiac death and MI in octogenarian patients with CAD or with suspicion of CAD.     

Prognostic value of myocardial perfusion imaging with adenosine triphosphate.

BACKGROUND: Pharmacologic stress with scintigraphy can predict prognosis in patients with coronary disease. Adenosine triphosphate (ATP) has been used in stress testing, but its efficacy in assessing prognosis has not been studied. METHODS AND RESULTS: A total of 150 patients (95 men, aged 64 +/- 10 years) were studied with thallium 201 during intravenous infusion of ATP and at rest. Perfusion defects were classified as reversible or mixed. The lung-heart ratio was calculated. During a maximum follow-up of 4.5 years, the following final events were considered: death, nonfatal myocardial infarction, angina or heart failure requiring hospitalization, or clinical need for myocardial revascularization. The prognostic value of different variables was analyzed with Cox regression. Groups with significantly worse prognosis were as follows: men, smokers, those with previous myocardial infarction, those with total cholesterol/high-density lipoprotein greater than 5, and those with lung-heart ratio greater than 0.5. Multivariate Cox regression showed the presence of perfusion defects as the only variable predictive of prognosis. It was time-dependent, with the highest risk at the beginning of follow-up. Mixed defects had the highest risk, followed by moderate to severe reversible defects. CONCLUSIONS: ATP with Tl-201 gamma-tomography is useful in predicting prognosis of patients with coronary artery disease.     

MR灌注成像对星形胶质细胞瘤肿瘤血管通透性的评价研究

目的　运用磁共振灌注成像 (PWI)获取对比剂首过期间的兴趣区图像 ,研究Ⅱ～Ⅳ级星形胶质细胞瘤肿瘤血管的通透性。方法　Ⅱ～Ⅳ级星形胶质细胞瘤共 2 3例 ,常规MR检查后以双倍剂量钆喷替酸葡甲胺 (Gd DTPA)行灌注加权成像 (PWI) ,获取兴趣区准T2 (T2 )增强的灌注图像 ,绘制出病灶的信号强度下降百分率 时间曲线 ,根据首过期末信号下降百分率与首过时间之比计算肿瘤血管的相对通透性 (P )。结果　正常脑组织信号在首过期末几乎恢复至基线 ,胶质瘤则仍有一定程度的信号下降 ,对比剂再循环引起的信号下降最早发生于首过期结束后 5s。Ⅱ、Ⅲ和Ⅳ级星形胶质细胞瘤的P 值分别为 0 19～ 0 4 8(0 32± 0 0 9)、0 71～ 1 2 9(0 98± 0 16 )、1 4 0～ 2 2 4 (1 92± 0 2 1) ,各组P 值两两比较经t检验发现Ⅱ级、Ⅲ级和Ⅳ级的P 值任意两者间差异均有非常显著性意义 (Ⅱ /Ⅲ ,t=7 2 8,P <0 0 0 1;Ⅲ /Ⅳ ,t=8 2 7,P <0 0 0 1;Ⅱ /Ⅳ ,t=14 0 ,P <0 0 0 1)。结论　灌注成像对评价星形胶质细胞瘤肿瘤血管通透性具有重要作用 ,不同分级的星形胶质细胞瘤其肿瘤血管通透性存在显著差异     

MR脑血流灌注成像在星形细胞肿瘤中的应用研究

目的　评价MR脑血流灌注成像在星形细胞肿瘤中的应用价值。方法　经手术及病理证实的星形细胞肿瘤共 2 6例。行常规MR及MR灌注成像检查。构建局部脑血容量 (rCBV)图 ,并计算肿瘤最大相对局部脑血容量 (rrCBV)值。评价星形细胞肿瘤的rCBV图表现 ,并分析平均最大rrCBV值与肿瘤病理学级别之间的关系。结果　 9例Ⅱ级星形细胞瘤的rCBV分布较均匀 ,接近或略高于对侧脑白质。 7例Ⅲ级和 10例Ⅳ级星形细胞肿瘤的rCBV分布明显不均匀 ,肿瘤实性区rCBV多有不同程度的升高 ;瘤内囊变坏死区和瘤周水肿区rCBV降低。增强MRI上 ,2例Ⅲ级和 2例Ⅳ级肿瘤内无明显强化区域 ,在rCBV图上脑血容量明显升高。Ⅱ～Ⅳ级肿瘤最大rrCBV的平均值分别为 0 91±0 18、3 5 1± 1 0 1和 4 75± 1 2 3;Ⅱ级与Ⅲ级 (t=6 79,P <0 0 1)、Ⅱ级与Ⅳ级 (t=9 75 ,P <0 0 1)、Ⅲ级与Ⅳ级之间 (t=2 19,P <0 0 5 )平均最大rrCBV值差异均有显著性意义。结论　MR脑血流灌注成像可观察星形细胞肿瘤的血流灌注变化 ,对判断星形细胞肿瘤的病理学分级有重要临床意义。     

磁共振顺磁性对比剂脑灌注成像的研究

目的 结合动态回波平面Ｔ２＾＊血流灌注成像在颅脑疾病诊断中的初步应用,总结正常成人与颅脑疾病患者血流灌注成像的表现,阐明ＭＲ顺磁性对比剂血流灌注成像的基本原理及颅脑疾病灌注成像表现的磁共振基础,讨论磁共振脑血流定量研究中存在的问题及其进一步的研究方向。方法 共４３例,其中健康成人８例,脑因或脑梗死病人２２例,病毒性脑炎２例,胶质瘤５例,脑膜瘤４例,神经鞘瘤２例。所有病例均行常规Ｔ２ＷＩ、Ｔ１ＷＩ、     

Acute ischemic stroke: predictive value of 2D phase-contrast MR angiography--serial study with combined diffusion and perfusion MR imaging

PURPOSE: To evaluate phase-contrast magnetic resonance (MR) angiography and diffusion- and perfusion-weighted imaging in predicting evolution of infarction and clinical outcome. MATERIALS AND METHODS: Phase-contrast angiographic and diffusion-weighted images obtained 1 and 2 days after acute middle cerebral artery (MCA) stroke were assessed in 43 patients; 39 underwent perfusion-weighted imaging on day 1. Follow-up phase-contrast angiographic and T2-weighted images (n = 38) were obtained on day 8. Clinical outcome was assessed at 3 months. Patients were assigned to three groups according to angiographic findings on day 1: group 1, absence of flow in proximal MCA (M1 segment); group 2, internal carotid artery (ICA) occlusion with collateral M1 flow; group 3, flow in ICA and M1. Differences in lesion volumes on diffusion- and perfusion-weighted maps among groups were compared with one-way analysis of variance with Tukey post hoc multiple comparisons. RESULTS: Patients in group 1 had significantly larger infarct growth, volumes of hypoperfusion on relative cerebral blood volume (rCBV) and relative cerebral blood flow maps, and initial and final infarct volumes than did other patients (P <.05). Initial perfusion deficits on mean transit time maps were significantly (P =.002) larger in group 2 than in group 3, but there were no significant differences in infarct growth (P =.977), final infarct volume on day 8 (P =.947), and clinical outcome (P =.969). Absence of M1 flow on day 1 was significantly associated with unfavorable clinical outcome (modified Rankin score > or = 3) at 3 months (P =.010, chi(2) test). Discriminant analysis revealed that rCBV maps alone and combination of diffusion-weighted imaging and MR angiography yielded the highest accuracy in predicting an unfavorable clinical outcome. CONCLUSION: Phase-contrast MR angiography can provide complementary information to that with diffusion- and perfusion- weighted imaging in predicting the outcome of patients with acute stroke.     

Prognostic value of myocardial perfusion imaging after first-line coronary computed tomography angiography: A multi-center cohort study

PurposeFurther diagnostic testing may be required after a coronary computed tomography angiography (CTA) showing suspected coronary stenosis. Whether myocardial perfusion imaging (MPI) provides further prognostic information post-CTA remains debated. We evaluated the prognosis for patients completing CTA stratified for post-CTA diagnostic work-up using real-world data.MethodsWe identified all patients in our uptake area with angina symptoms undergoing first-time CTA over a 10-year period. Follow-up time was a median of 3.7 years [1.9–5.8]. The primary endpoint was a composite of myocardial infarction or death. The secondary endpoint was late revascularization.ResultsDuring the study period 53,351 patients underwent CTA. Of these, 24% were referred for further down-stream testing, 3,547 (7%) to MPI and 9,135 (17%) to invasive coronary angiography (ICA). The primary and secondary endpoints occurred in 2,026 (3.8%) and 954 (1.8%) patients. Patient-characteristic-adjusted hazard ratios for the primary and secondary endpoint using patients with a normal CTA as reference were 1.37 (1.21–1.55) and 2.50 (1.93–3.23) for patient treated medically, 1.68 (1.39–2.03) and 6.13 (4.58–8.21) for patients referred to MPI and 1.94 (1.69–2.23) and 9.18 (7.16–11.78) for patients referred for ICA, respectively. Adjusted analysis with stratification for disease severity at CTA showed similar hazard ratios for patients treated medically after CTA and patients referred for MPI and treated medically after the MPI.ConclusionIn patients completing coronary CTA, second-line MPI testing seems to identify patients at low risk of future events. MPI seems to have the potential to act as gatekeeper for ICA after coronary CTA.     

Prognostic value of myocardium perfusion imaging with a new reconstruction algorithm

Background

It has been demonstrated that a new reconstruction algorithm for myocardium perfusion imaging (MPI) allows faster acquisition with similar accuracy. The prognostic value of MPI performed with this software and short acquisition time is unknown.

Methods

To determine the prognostic value we followed 3184 consecutive MPI patients between March 2008 and March 2010. A 2-day protocol with low dose 99mTc-MIBI (10-12 mCi) and a 6-minute acquisition was used. Exercise stress was used in 62.6 % of the studies. Scans were reconstructed using the software “Evolution for cardiac”. Perfusion defects were quantified by summed stress score (SSS) and categorized in four groups: SSS0 = 0; SSS1 = 1-3; SSS2 = 4-8; and SSS3 ≥ 9. Patients were phone contacted every 6 months for follow up and hard events were defined as death or myocardial infarction (MI) and total events as hard events plus late revascularization.

Results

The mean radiation dose was <7 mSv/patient. Mean F/U was 33 ± 20 months; 140 of the patients were lost to follow up and 86 were censored due early revascularization (<60 days after MPS). There were 140 hard events: 89 deaths and 51 MI. Mean age was 61.5 ± 12.3 years and 57.7 % were male. Hard event rate was 0.8 %/year in patients with normal MPS and 3.7 %/year in those with abnormal MPS. Patients with larger defects had nine times more hard events than patients with SSS = 0 (14.2 % vs 1.6 %). Revascularization was more frequent in patients with abnormal MPS than normal MPS (21.7 % vs 3.9 %; P < 0.001). Cox proportional hazard analysis showed that SSS was an independent predictor of hard events and revascularization.

Conclusions

The use of reduced-dose, fast myocardial perfusion SPECT and the new processing algorithm lowers acquisition time and radiation exposure compared to conventional SPECT without compromising the well-established prognostic value of MPI.