Cerebral perfusion SPECT in transient ischemic attack

18F-FDG PET/CT in immunocompetent patients with primary central nervous system lymphoma: Differentiation from glioblastoma and correlation with DWI

OBJECTIVES

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is useful for the detection of cancerous lesions, and FDG uptake is related to the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) of extracranial tumors. The purpose of our study was to investigate the ability of FDG PET/CT in distinguishing primary central nervous system lymphoma (PCNSL) from glioblastoma multiforme (GBM) and to explore the relationship between ¹⁸F-FDG uptake and the ADC in patients with PCNSL.

METHODS

We reviewed 92 patients (40 with PCNSL and 52 with GBM) who underwent FDG PET/CT scans at disease onset. The maximum standardized uptake value (SUVmax), tumor to normal contralateral cortex activity (T/N) ratio, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of tumor lesions were calculated. Receiver operating characteristic (ROC) curves were generated to determine the diagnostic performance for FDG PET-related parameters to differentiate PCNSL from GBM. Twenty-eight patients with PCNSL (with 34 lesions) also underwent diffusion-weighted imaging. Pearson's correlation analysis was used to assess the relation between SUV- and ADC-derived parameters.

RESULTS

The SUVmax, T/N ratio, SUVmean, and TLG values were significantly higher in PCNSL than in GBM. Comparative ROC analysis indicated that the SUVmax had a greater area under the curve (AUC) of 0.910 than the T/N ratio (0.905, P = .85), SUVmean (0.836, P = .0006), or TLG (0.641, P < 0.0001). The T/N ratio had the highest specificity (94.23%) for differentiating PCNSL from GBM, while the SUVmax had the most optimal sensitivity (92.31%). Further combined analysis of the indices did not significantly improve the AUC. Moderate inverse correlations between the SUVmax, SUVmean, TLG, and the ADC ratio (rADC) were found in PCNSLs (r = -0.526, P = .002; r = -0.504, P = .004; and r = -0.483, P = .006; respectively).

CONCLUSIONS

The SUVmax and T/N ratio may be reliable measures for differentiating PCNSLs from GBMs. Additionally, FDG metabolism indices were inversely proportional to the rADCs of PCNSL lesions.

Yizhi Xingnao prescription improves the cognitive function of patients after a transient ischemic attack

Patients with mild cognitive impairment after a transient ischemic attack were included in this study. They were treated with Yizhi Xingnao prescription, ergoloid mesylates or aspirin for 60 days. Evaluation using the Montreal Cognitive Assessment Scale showed that cognitive function was significantly improved in all patients, especially after the combined treatment of Yizhi Xingnao and aspirin. The scores from the Montreal Cognitive Assessment Scale were improved overall and the effective treatment rate was as high as 79%, which was higher than patients treated with a combination of ergoloid mesylates and aspirin, or aspirin alone. Our experimental findings indicate that Yizhi Xingnao prescription can improve mild cognitive impairment after a transient ischemic attack, and that it is more effective than ergoloid mesylates.

1H-MR spectroscopy changes in transient ischemic attack patients and their correlation with perfusion-weighted imaging

PURPOSE

We investigated whether patients with transient ischemic attack (TIA) have metabolic changes in the brain.

METHODS

35 patients with clinically diagnosed TIA were prospectively included in our study. Clinical and neurological data were compiled. 1H-MR spectroscopy and perfusion-weighted imaging were performed in all patients within 3 days of the onset of symptoms.

RESULTS

In TIA patients, the N-acetylaspartate (NAA)/choline (Cho) ratio in noninfarcted regions was significantly decreased in the symptomatic hemisphere (1.33 +/- 0.38) compared with the asymptomatic hemisphere (1.51 +/- 0.41, p < .05). Patients with a history of prior TIA had a significantly decreased NAA/Cho ratio in both the symptomatic (p < .05) and asymptomatic (p < .05) hemispheres compared with TIA patients without a prior TIA. TIA patients with diffusion-weighted imaging lesions had a significantly increased lactate/NAA ratio in both the symptomatic (p < .05) and asymptomatic (p < .05) hemispheres compared with TIA patients without lesions. The relative cerebral blood flow (rCBF) value was directly related to the symptomatic Cho/creatine (Cr) value (r = 0.81, p < .01). The higher the rCBF value, the higher the symptomatic Cho/Cr value.

CONCLUSIONS

TIA patients have neurological deficits that are transient; however, metabolic damage to the brain is present up to 3 days after the onset of the symptoms. These metabolic changes are not restricted to the symptomatic hemisphere or to areas close to ischemic lesions and the changes are related in the CBF.

Hemodynamic and metabolic changes in transient ischemic attack patients: a magnetic resonance angiography and (1)H-magnetic resonance spectroscopy study performed within 3 days of onset of a transient ischemic attack

BACKGROUND AND PURPOSE

We investigated whether patients with transient ischemic attack (TIA) have systemic low flow to the brain or an abnormal intracranial flow distribution caused by an abnormal anatomy of the circle of Willis. Furthermore, we investigated whether metabolic changes were present in the brain.

METHODS

Forty-four patients with clinically diagnosed TIA were prospectively included in our study. Clinical and neurological data were compiled. MR imaging; quantitative flow measurements of the internal carotid, middle cerebral, and basilar arteries; MR angiography of the circle of Willis; and (1)H-MR spectroscopy were performed in all patients within 3 days of onset of symptoms.

RESULTS

Compared with control subjects, TIA patients did not have altered flow volume in any of the arteries and had normal flow distribution through the circle of Willis. In TIA patients, the N-acetylaspartate (NAA)/choline ratio in noninfarcted regions was significantly decreased in the symptomatic hemisphere (1.73+/-0.16) compared with the asymptomatic hemisphere (1.84+/-0.19, P<0.05) and control subjects (1.90+/-0.17, P<0.001). In the symptomatic hemisphere, the lactate/NAA ratio was significantly increased (0.04+/-0.08) compared with control subjects (0.00+/-0.01, P<0.05). Patients with a history of prior TIA had a significantly decreased NAA/choline ratio in both the symptomatic (P<0.05) and asymptomatic (P<0.05) hemispheres compared with TIA patients without a prior TIA.

CONCLUSIONS

TIA patients have neurological deficits that are transient; however, metabolic damage to the brain is present up to 3 days after the onset of the symptoms. These metabolic changes are not restricted to the symptomatic hemisphere or to areas close to ischemic lesions.