Prognostic value of brain perfusion single-photon emission computed tomography (SPECT) for language recovery in patients with aphasia

AIM: To determine the prognostic value of brain perfusion single-photon emission computed tomography (SPECT) in patients with aphasia after a stroke. METHODS: Brain perfusion SPECT with 99mTc-ethyl cysteinate dimer (99mTc-ECD) was used in 16 right-handed patients with aphasia after a left-sided cerebrovascular accident (CVA) in the early chronic period after the onset of CVA. The region of interest (ROI) method was used to calculate the relative regional cerebral blood flow (rCBF) in each cerebral lobe, the thalamus, the putamen and the cerebellum as ratios to the count in the left cerebellar hemisphere. The Standard Language Test of Aphasia (SLTA) was performed twice, once at the same time as SPECT, a mean of 2.3 months after CVA onset (early SLTA), and again a mean of 17.0 months after CVA onset (late SLTA). In addition to the overall language function score, scores for taking dictation (Dictation), oral reading (Speaking) and comprehension (Comprehension) were calculated, and the correlations with each of the rCBF values were evaluated. RESULTS: Left temporal CBF correlated with the late Dictation score; bilateral frontal, bilateral temporal and right parietal CBF correlated with the late Speaking score; and right frontal, left temporal and left occipital CBF correlated with the late Comprehension score. CONCLUSION: Brain perfusion SPECT in the early chronic stage was shown to be useful for predicting recovery from aphasia, recovery of oral reading, ability to take dictation and comprehension.     

Attenuation correction single-photon emission computed tomography myocardial perfusion imaging

Clinicians now rely heavily on the results of single-photon emission computed tomography (SPECT) myocardial perfusion imaging for diagnosing coronary disease and for planning therapy. However, the technique is imperfect for these purposes, mainly because of technical limitations, the most prominent of which is the effect of soft-tissue attenuation on apparent tracer distribution. Providers have attempted to compensate for this by a number of indirect approaches. Recently, validated hardware and software solutions for directly correcting image data for soft-tissue attenuation have become widely available commercially. Optimal application requires an understanding of the technical details that differ somewhat from system to system, the quality control prerequisites, knowledge of the importance of the transmission map quality, and how dedicated SPECT and SPECT-computed tomography systems present different challenges. In addition, the clinical literature is expanding rapidly, including studies on diagnostic accuracy, image appearances, quantitative analysis, appropriate patients for attenuation correction, clinical utility, incremental value in relation to ECG-gating, and risk stratification.     

Reducing the small-heart effect in pediatric gated myocardial perfusion single-photon emission computed tomography

Background

We compared two reconstruction algorisms and two cardiac functional evaluation software programs in terms of their accuracy for estimating ejection fraction (EF) of small hearts (SH).

Methods

The study group consisted of 66 pediatric patients. Data were reconstructed using a filtered back projection (FBP) method without the resolution correction (RC) and an iterative method based on an ordered subset expectation maximization (OSEM) algorithm with the RC. EF was evaluated using two software programs of quantitative gated single-photon emission computed tomography (SPECT) (QGS) and cardioREPO. We compared the EF of gated myocardial perfusion SPECT to echocardiographic measurement (Echo).

Results

Forty-eight of 66 patients had an end-systolic volume < 20 mL which was used as the criterion for being included in the SH group, and the SH effect led to an overestimation of EF. While significant differences were observed between Echo (66.9 ± 5.0%) and QGS-FBP without RC (76.9 ± 8.4%, P < .0001), QGS-OSEM with RC (76.6 ± 8.6%, P < .0001), and cardioREPO-FBP without RC (72.1 ± 10.0%, P = .0011), no significant difference was observed between Echo and cardioREPO-OSEM with RC (67.4 ± 6.1%) in SH group.

Conclusions

In pediatric gated myocardial perfusion SPECT, the SH effect can be significantly reduced when an OSEM algorithm is used with RC in combination with the specific cardioREPO algorithm.

     

Application of single-photon emission computed tomography (SPECT) with99mTc-MAA in evaluation of perfusion patterns during hepatic infusion chemotherapy

In 6 patients receiving hepatic artery infusion chemotherapy for liver metastases, planar and single-photon emission computed tomography (SPECT) images of the abdomen were obtained after intravenous injection of 99mTc-phytate, and intra-catheter injection of 99mTc-MAA in the same geometrical settings. With this method, the three-dimensional intra- and extra-hepatic distribution of the agents during hepatic artery infusion chemotherapy can be evaluated.     

Prognostic evaluation of patients after myocardial infarction: Incremental value of sestamibi single-photon emission computed tomography and echocardiography

Background

This study compares the prognostic value of ^99mTc-labeled methoxyisobutyl isonitrile (MIBI) single-photon emission computed tomographic (SPECT) imaging, echocardiography, and other clinical and laboratory prognostic factors in the long-term risk stratification of patients with stable uncomplicated infarcts.

Methods and Results

Ninety-one consecutive patients affected by a first myocardial infarction without serious complications were enrolled. After at least 3 months from the infarction, they were submitted to stress-rest MIBI SPECT and rest echocardiography. Eighty-six patients completed a follow-up of at least 4 years (range 48 to 72 months; mean 55 months). By univariate (log-rank test) and multivariate analysis (Cox proportional hazards model), the main clinical, electrocardiographic, scintigraphic, and echocardiographic findings were evaluated and correlated statistically with the incidence of ensuing cardiac events. Twenty-five patients had cardiac events during the follow-up (four cardiac deaths, four myocardial infarctions, and 17 cases of unstable angina). At the multivariate analysis, the presence of reversible defects on MIBI SPECT (p=0.008 and relative risk [RR]=7.09), the wall motion score index, and the ejection fraction at echocardiography (respectively, p=0.010, RR=3.67, p=0.036, and RR=3.12), and stress angina (p=0.007 and RR=3.40) were significant and independent prognostic factors.

Conclusions

In our long-term follow-up, MIBI SPECT and echocardiography appeared to be significant and independent prognostic tools in the risk stratification of patients with stable, uncomplicated infarcts, furnishing complementary information. The reversibility of MIBI defects appeared the best indicator for a bad prognosis.     

Functional mapping of ventricular contraction and phase using single-photon emission computed tomography (SPECT)

A method for functional mapping of ventricular contraction and phase was developed using gated blood-pool SPECT. Parameters of contraction and phase were calculated using length-based and count-based Fourier analyses. In length-based Fourier analysis (LFA), percentage-shortening and length-based phase were calculated based on the changes of lengths from a ventricular centre to edges. In count-based Fourier analysis (CFA), phase and amplitude were also calculated using serial tomographic phase images. Two-dimensional polar display format was employed to summarize the SPECT data of whole cardiac surface. This program was applied to evaluate coronary artery disease and conduction anomalies. The polar functional map using gated blood-pool SPECT can be an effective method to integrate three-dimensional cardiac information in conjunction with myocardial SPECT studies.     

Incremental prognostic value of coronary flow reserve assessed with single-photon emission computed tomography

Background  

We assessed the prognostic value of coronary flow reserve (CFR) estimated by single-photon emission computed tomography (SPECT) in patients with suspected myocardial ischemia.     

Long-term prognostic value of exercise technetium-99m tetrofosmin myocardial perfusion single-photon emission computed tomography

Background

Exercise ^99mTc-tetrofosmin single-photon emission computed tomography (SPECT) is a useful tool for short- and medium-term risk stratifications. Currently, the long-term prognostic application of this technique has not been evaluated.

Methods and Results

Exercise ^99mTc-tetrofosmin was performed in 655 consecutive patients. Ten patients who underwent revascularization <60?days after nuclear testing were excluded from the analysis. The present data are based on 638 patients with complete follow-up. An abnormal SPECT study was defined as the presence of fixed and/or reversible perfusion defects. End points were cardiac death, nonfatal infarction, and late coronary revascularization. A total of 344 (54%) patients had an abnormal SPECT study. Perfusion defects included fixed defects alone in 186 patients (29%) and reversible defects in 158 (25%) patients. During a mean follow-up of 11.0?±?3.3?years, 174 (27%) patients died (all-cause mortality). Nonfatal myocardial infarction occurred in 76 (12%) patients, and late coronary revascularization was performed in 194 (30%) patients. Univariable and multivariable Cox proportional hazard regression analyses showed that exercise ^99mTc-tetrofosmin SPECT provided prognostic information incremental to clinical data and exercise test data. Patients with a normal SPECT had a relatively favorable long-term prognosis, in contrast to patients with an abnormal study who had a significantly increased risk of cardiac events. The SPECT parameters abnormal scan, reversible defect, and summed rest score were strong predictors of long-term outcome.

Conclusion

Exercise ^99mTc-tetrofosmin myocardial perfusion SPECT has an incremental long-term prognostic value over clinical and stress test parameters for the prediction of major adverse cardiac events.     

Technologist corner: Reducing the small-heart effect in pediatric gated myocardial perfusion single-photon emission computed tomography

Journal of Nuclear Cardiology -     

Usefulness and limitations of ECG-gated myocardial single-photon emission computed tomography with 99mTc-methoxy-isobutyl-isonitrile (MIBI) in patients with prior myocardial infarction]

To evaluate the relationship between regional wall motion and 99mTc-methoxy-isobutyl-isonitrile (MIBI) uptake, ECG-gated single-photon emission computed tomography (SPECT) with 99mTc-MIBI was performed in 20 patients with prior myocardial infarction. The left ventricular images at end-diastole (ED) and end-systole (ES) were divided into 39 segments, respectively. Based on circumferential profile analysis, relative uptake (%EDc, %ESc), percent count increase (% delta C), and normalized percent count increase (% delta Cn) were analyzed in each segment and compared with regional wall motion indices assessed by echocardiography and left ventriculography. ECG-gated SPECT with 99mTc-MIBI provided high contrast tomograms of the left ventricular myocardium. %EDc and %ESc showed good correlations with regional wall motion indices. % delta C and % delta Cn, however, showed lower correlations compared with %EDc and %ESc. In conclusion, high-quality left ventricular images were obtained with 99mTc-MIBI ECG-gated SPECT, but quantitative analysis based on only percent count increase (% delta C) have limitations for evaluation of regional wall motion.