Recent advances in arterial spin labeling perfusion MRI in patients with vascular cognitive impairment.

Cognitive impairment (CI) is a major health concern in aging populations. It impairs patients' independent life and may progress to dementia. Vascular cognitive impairment (VCI) encompasses all cerebrovascular pathologies that contribute to cognitive impairment (CI). Moreover, the majority of CI subtypes involve various aspects of vascular dysfunction. Recent research highlights the critical role of reduced cerebral blood flow (CBF) in the progress of VCI, and the detection of altered CBF may help to detect or even predict the onset of VCI. Arterial spin labeling (ASL) is a non-invasive, non-ionizing perfusion MRI technique for assessing CBF qualitatively and quantitatively. Recent methodological advances enabling improved signal-to-noise ratio (SNR) and data acquisition have led to an increase in the use of ASL to assess CBF in VCI patients. Combined with other imaging modalities and biomarkers, ASL has great potential for identifying early VCI and guiding prediction and prevention strategies. This review focuses on recent advances in ASL-based perfusion MRI for identifying patients at high risk of VCI.

Analysis on risk factors of lung cancer complicated with pulmonary embolism.

INTRODUCTION: Pulmonary embolism (PE) is a potentially fatal complication and its morbidity together with fatalness will further increase when in patients with malignant tumors. Fast and accurate early diagnosis of PE thus seems considerably important. OBJECTIVE: To explore the risk factors of lung cancer complicated with PE. MATERIALS AND METHODS: A retrospective cohort study consisted of 40 lung cancer patients with PE (PE group) and 60 lung cancer patients without PE (non-PE group) were analyzed. RESULTS: The white blood cell (WBC) count, D-dimer and low-density lipoprotein (LDL) were higher in PE group than those in non-PE group (P < 0.05), whereas the arterial partial pressure of oxygen (PaO2 ) in PE group was lower than that in non-PE group (P < 0.05). Carcinoembryonic antigen (CEA) level between two groups also exhibited statistical difference (P < 0.05). Those lung adenocarcinoma patients with stages III and IV tumor, coupled with deep venous thrombosis (DVT), having experienced bevacizumab treatment or platinum-based chemotherapy more likely suffered from PE (P < 0.05). The multivariate analysis revealed that high D-dimer, chemotherapy, DVT, stages III to IV, adenocarcinoma were independent risk factors associated with PE (P < 0.05). The overall survival time of patients in case group was significantly shorter than that in the control group with a median survival duration being 10.5 months (95%CI, 8.95-12.05) and 16.8 months (95%CI, 14.62-18.98), respectively, (P < 0.01). CONCLUSIONS: High D-dimer, chemotherapy, DVT, stages III to IV and adenocarcinoma might have a positive correlation with PE, meanwhile, PE always predicted a poor prognosis in lung cancer patients.

Crossed cerebellar diaschisis after stroke detected noninvasively by arterial spin-labeling MR imaging.

BACKGROUND: As a noninvasive perfusion-weighted MRI technique, arterial spin-labeling (ASL) was becoming increasingly used to evaluate cerebral hemodynamics in many studies. The relation between ASL-MRI and crossed cerebellar diaschisis (CCD) was rarely discussed. In this study, the aim of our study was to assess the performance of ASL-MRI in the detection of crossed cerebellar diaschisis after stroke in compared with single-photon emission CT (SPECT). RESULTS: 17 of 51(33.3%) patients revealed CCD phenomenon by the SPECT method. In CCD-positive group, CBFASL of ipsilateral cerebellar were significantly increased compared with contralateral cerebellar (p < 0.0001) while no significant differences (p = 0.063, > 0.001) in the CCD-negative group. Positive correlation was detected between admission National institute of health stroke scale (NIHSS) and asymmetry index of SPECT (AISPECT) (r = 0.351, p = 0.011), AIASL (r = 0.372, p = 0.007); infract volume and AISPECT (r = 0.443, p = 0.001), AIASL (r = 0.426, p = 0.002). Significant correlation was also found between cerebral blood flow of SPECT (CBFSPECT) and CBFASL, AISPECT and AIASL (r = 0.204, p = 0.04; r = 0.467, p = 0.001, respectively). Furthermore, the area under the receiver operating characteristic (ROC) curve value of AIASL was 0.829. CONCLUSIONS: CBF derived from ASL-MRI could be valuable for assessment of CCD in supratentorial stroke patients. Additionally, CCD was significantly associated with larger ischemic volume and higher initial NIHSS score.

Rosiglitazone ameliorates tissue plasminogen activator-induced brain hemorrhage after stroke.

OBJECTIVE: Delayed thrombolytic therapy with recombinant tissue plasminogen activator (tPA) may exacerbate blood-brain barrier (BBB) breakdown after ischemic stroke and lead to catastrophic hemorrhagic transformation (HT). Rosiglitazone(RSG), a widely used antidiabetic drug that activates peroxisome proliferator-activated receptor-γ (PPAR-γ), has been shown to protect against cerebral ischemia through promoting poststroke microglial polarization toward the beneficial anti-inflammatory phenotype. However, whether RSG can alleviate HT after delayed tPA treatment remains unknown. In this study, we sort to examine the role of RSG on tPA-induced HT after stroke. METHODS AND RESULTS: We used the murine suture middle cerebral artery occlusion (MCAO) models of stroke followed by delayed administration of tPA (10 mg/kg, 2 hours after suture occlusion) to investigate the therapeutic potential of RSG against tPA-induced HT. When RSG(6 mg/kg) was intraperitoneally administered 1 hour before MCAO in tPA-treated MCAO mice, HT in the ischemic territory was significantly attenuated 1 day after stroke. In the tPA-treated MCAO mice, we found RSG significantly mitigated BBB disruption and hemorrhage development compared to tPA-alone-treated stroke mice. Using flow cytometry and immunostaining, we confirmed that the expression of CD206 was significantly upregulated while the expression of iNOS was down-regulated in microglia of the RSG-treated mice. We further found that the expression of Arg-1 was also upregulated in those tPA and RSG-treated stroke mice and the protection against tPA-induced HT and BBB disruption in these mice were abolished in the presence of PPAR-γ antagonist GW9662 (4 mg/kg, 1 hour before dMCAO through intraperitoneal injection). CONCLUSIONS: RSG treatment protects against BBB damage and ameliorates HT in delayed tPA-treated stroke mice by activating PPAR-γ and favoring microglial polarization toward anti-inflammatory phenotype.

The peripheral immune response after stroke-A double edge sword for blood-brain barrier integrity.

The blood-brain barrier (BBB) is a highly regulated interface that separates the peripheral circulation and the brain. It plays a vital role in regulating the trafficking of solutes, fluid, and cells at the blood-brain interface and maintaining the homeostasis of brain microenvironment for normal neuronal activity. Growing evidence has led to the realization that ischemic stroke elicits profound immune responses in the circulation and the activation of multiple subsets of immune cells, which in turn affect both the early disruption and the later repair of the BBB after stroke. Distinct phenotypes or subsets of peripheral immune cells along with diverse intracellular mechanisms contribute to the dynamic changes of BBB integrity after stroke. This review focuses on the interaction between the peripheral immune cells and the BBB after ischemic stroke. Understanding their reciprocal interaction may generate new directions for stroke research and may also drive the innovation of easy accessible immune modulatory treatment strategies targeting BBB in the pursuit of better stroke recovery.

Young patient with arterial thrombosis and skin changes as the onset manifestations: POEMS syndrome.

POEMS syndrome is a rare multi-systemic disease characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes. Arterial thrombosis is a distinctively unusual feature in patients with POEMS syndrome. We report a 33-year-old man with intermittent amaurosis of left eye and skin changes as the onset manifestations, who was finally confirmed as having POEMS syndrome. Most notably, this was a young man without high risk factors of arterial thrombosis and no monoclonal protein was detected until the repeated measurement later. This case evokes the need to consider the diagnosis of POEMS syndrome for young patients with symptoms of arterial thrombosis but no high risk factors of thrombosis.

Association between Triglyceride to HDL-C Ratio (TG/HDL-C) and Insulin Resistance in Chinese Patients with Newly Diagnosed Type 2 Diabetes Mellitus.

OBJECTIVES: To explore the association between the triglyceride to HDL-C ratio (TG/HDL-C) and insulin resistance in Chinese patients with newly diagnosed type 2 diabetes mellitus. METHODS: Patients with newly diagnosed type 2 diabetes mellitus (272 men and 288 women) were enrolled and divided into three groups according to TG/HDL-C tertiles. Insulin resistance was defined by homeostatic model assessment of insulin resistance (HOMA-IR). Demographic information and clinical characteristics were obtained. Spearman's correlation was used to estimate the association between TG/HDL-C and other variables. Multiple logistic regression analyses were adopted to obtain probabilities of insulin resistance. A receiver operating characteristic analysis was conducted to evaluate the ability of TG/HDL-C to discriminate insulin resistance. RESULTS: TG/HDL-C was associated with insulin resistance in Chinese patients with newly diagnosed T2DM (Spearman's correlation coefficient = 0.21, P < 0.01). Patients in the higher tertiles of TG/HDL-C had significantly higher HOMA-IR values than patients in the lower tertiles [T1: 2.68(1.74-3.70); T2: 2.96(2.29-4.56); T3: 3.09(2.30-4.99)]. Multiple logistic regression analysis showed that TG/HDL-C was significantly associated with HOMA-IR, and patients in the higher TG/HDL-C tertile had a higher OR than those in the lower TG/HDL-C tertile, after adjusting for multiple covariates including indices for central obesity [T1: 1; T2: 4.02(1.86-8.71); T3: 4.30(1.99-9.29)]. Following stratification of waist circumference into quartiles, the effect of TG/HDL-C on insulin resistance remained significant irrespective of waist circumference. CONCLUSIONS: TG/HDL-C was associated with insulin resistance independent of waist circumference. Whether it could be a surrogate marker for insulin resistance in Chinese patients with newly diagnosed type 2 diabetes mellitus still needs to be confirmed by more researches.

Usefulness of dual-energy computed tomography imaging in the differential diagnosis of sellar meningiomas and pituitary adenomas: preliminary report.

OBJECTIVE: To quantitatively assess the imaging characteristics of sellar lesion in dual-energy computed tomography (CT) imaging for differentiation of sellar meningiomas and pituitary adenomas during the arterial phase (AP) and venous phase (VP). MATERIALS AND METHODS: 51 patients with sellar/parasellar tumors (33 macroadenomas and 18 meningiomas) were examined with CT spectral imaging during the AP and the VP. Iodine concentrations were derived from iodine-based material-decomposition CT images and normalized to the iodine concentration in the aorta. The difference in Normalized iodine concentrations (NICs), HU curve slope (λHU), and mean CT values of lesions between the AP and VP were calculated. The two-sample t test was performed to compare quantitative parameters between sellar meningiomas and pituitary adenomas. RESULTS: NICs, λHU, and mean CT values in patients with sellar meningiomas differed significantly from those in patients with pituitary adenomas: Mean NICs were 43.52 mg/mL±1.35 versus 9.23 mg/mL ±2.44, respectively, during the AP and 52.13 mg/mL ±1.04 versus 24.37 mg/mL ±2.23 respectively, during the VP. λHU were -3.03±3.42 versus -0.53±0.23, respectively, during the AP and -2.96±0.41 versus -0.47±0.25, respectively, during the VP. Mean CT values were 193.63±2.08 versus 63.98±2.85, respectively, during the AP and 203.98±0.18 versus 77.66±0.91, respectively, during the VP. The combination of NIC and Mean CT value during VP had highest sensitivity (90.9%) and specificity (100%) among all phases. CONCLUSION: Quantitative dual-energy CT imaging has promising potential for diagnostic differentiation of sellar meningiomas and pituitary adenomas.

Influence of fluid-attenuated inversion-recovery on stroke apparent diffusion coefficient measurements and its clinical application.

BACKGROUND AND PURPOSE: The application of a fluid-attenuated inversion-recovery pulse with a conventional diffusion-weighted MRI sequence (FLAIR DWI) decreases the partial volume effects from cerebrospinal fluid on apparent diffusion coefficient (ADC) measurements. For this reason, FLAIR DWI may be more useful in the evaluation of ischemic stroke, but few studies have looked at the effect of FLAIR on ADC measurements in this setting. This study quantitatively compares FLAIR DWI and conventional DWI in ischemic stroke of varying ages to assess the potential advantages of this technique. METHODS: We respectively analyzed 139 DWI studies in patients with ischemic stroke with and without FLAIR at varying time points ranging from hyperacute to chronic. ADC values were measured in each lesion, as well as in the contralateral normal side. Comparisons were made between the ADC values obtained from the DWI sequences with and without FLAIR for both the lesion and the normal contralateral side. RESULTS: The ADC measurements within the ischemic lesion were very similar on FLAIR DWI and conventional DWI for lesions less than 14 days old (p>0.05), but were significantly decreased on FLAIR DWI for lesions between 15 and 30 days old and in lesions >31 days old (chronic stage) (p<0.01). The contralateral ADC values were all significantly decreased on the FLAIR DWI sequence compared with conventional DWI (p<0.01). CONCLUSIONS: The application of an inversion pulse does not significantly affect the ADC values for early stage ischemic stroke (less than 14 days from symptom onset), but results in a more accurate relative ADC measurement by reducing the cerebrospinal fluid partial volume effects of the normal contralateral side. In addition, combined with the conventional DWI, FLAIR DWI may be helpful in determining the age of ischemic lesions.