Imaging investigation of cervicocranial artery dissection by using high resolution magnetic resonance VWI and MRA: qualitative and quantitative analysis at different stages.

BACKGROUND: To explore the value of magnetic resonance angiography (MRA) and high resolution magnetic resonance vessel wall imaging (HRMR-VWI) in cervicocranial artery dissection (CCAD) for the disease diagnosis, course staging and treatment. On the basis of qualitative evaluation, this study also extract the changes of different stages in vessel wall in different vessel segments to identify imaging indicators for the quantitative evaluation of CCAD. METHODS: We retrospectively enrolled 34 patients with CCAD (38branches) with conventional MRA and HRMR-VWI examinations. Two radiologists independently analyzed imaging features of vessel wall and lumen in the different stages, and the typical sign detection of artery dissection were compared between MRA and HRMR-VWI. Then the parameters of vessel wall was quantitatively evaluated by the post-processing software (Vesselmass, Leiden University Medical Center, Leiden, The Netherlands. RESULTS: HRMR-VWI revealed typical sign detection of artery dissection in all patients in the acute and subacute stage. Among them, the intimal flap/double lumen sign ditection were more common than the MRA, there was significant difference (P = 0.012). MRA revealed typical sign detection of artery dissection in more than half the patients, and the detection was no significant difference at the chronic stage between MRA and HRMR-VWI (P = 1.000/1.000/0.761). In the acute and subacute stage, the typical sign detection of intramural hematoma and Grade II enhancement revealed by HR-MRI was higher than the observations in the chronic stage (P = 0.000/0.000/0.016), while there was no significant difference by MRA (P = 0.902). The values of wall thickness, relative signal intensity of vessel wall enhancement, relative signal intensity of intramural hematoma (IMH), and percentage of stenosis in CCAD decreased from acute to subacute and then to chronic stages. Each quantitative parameter in patients with CCAD in the early stages (i.e., acute and subacute stages) was significantly different from that in patients with CCAD in the recovered group at chronic stage (P < 0.05). Wall thickness and relative signal intensity of vessel wall enhancement in patients with CCAD in the early stages were not significantly different from those in patients with CCAD in the incompletely recovered group at chronic stage (P > 0.05). CONCLUSIONS: As the only noninvasive imaging technology, HRMR-VWI displays the structure of the vessel wall in vivo, showing not only excellent performance in the early diagnosis of CCAD, but also describing the changes of different stages in the qualitative and quantitative characteristics of vessel wall. It also helps to guide the diseasediagnosis, course staging and treatment of CCAD. Although the diagnostic efficacy of MRA was not as good as HRMR-VWI, it should be the first choice of method for routine examination in evaluating CCAD, especially at the chronic stage of CCAD.

Application of 3.0T high-resolution magnetic resonance imaging for the diagnosis of stenotic vessel wall plaques in the middle cerebral artery: a study on fitness of professional athletes

Objective: To investigate the value of 3.0T high-resolution magnetic resonance imaging (HR-MRI) in the diagnosis of plaque in the vessel wall of middle cerebral artery stenosis. Methods: 41 patients with middle cerebral artery stenosis admitted from January 2018 to January 2020 were selected for the study, all of whom underwent HR-MRI, and the diagnostic results of digital subtraction angiography (DSA) were used as the gold standard to compare HR-MRI findings in middle cerebral artery stenosis with DSA diagnostic results. The NWI and responsible plaque heights of non-ischemic stroke and ischemic stroke patients at 6 months, 12 months, 18 months and 24 months after discharge were compared. Results: 41 patients were found to have stenosis in 49 middle cerebral arteries by DSA, including 33 cases of unilateral stenosis and 8 cases of bilateral stenosis. The diagnostic accuracy, specificity and sensitivity of HR-MRI in middle cerebral artery stenosis were 93.90% (77/82), 90.91% (30/33), 95.92% (47/49). There was no obvious distinction in NWI and responsible plaque height at 6, 12, 18 and 24 months after discharge in patients with ischemic stroke (P > 0.05). When comparing NWI and responsible plaque height at corresponding time points after discharge in non-ischemic stroke patients, the distinctions were not obvious (P > 0.05). Compared with the group of ischemic stroke, the non-ischemic stroke group NWI was lower at corresponding time points (P < 0.05). No obvious distinctions were found between the group of ischemic stroke and the group of non-ischemic stroke in terms of responsible plaque height at 6, 12, 18 and 24 months after discharge (P > 0.05). (AU)

Neural Induction Potential and MRI of ADSCs Labeled Cationic Superparamagnetic Iron Oxide Nanoparticle In Vitro.

Magnetic resonance imaging (MRI) combined with contrast agents is believed to be useful for stem cell tracking in vivo, and the aim of this research was to investigate the biosafety and neural induction of SD rat-originated adipose derived stem cells (ADSCs) using cationic superparamagnetic iron oxide (SPIO) nanoparticle which was synthesized by the improved polyol method, in order to allow visualization using in vitro MRI. The scan protocols were performed with T2-mapping sequence; meanwhile, the ultrastructure of labeled cells was observed by transmission electron microscopy (TEM) while the iron content was measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). After neural induction, nestin and NSE (neural markers) were obviously expressed. In vitro MRI showed that the cationic PEG/PEI-modified SPIO nanoparticles could achieve great relaxation performance and favourable longevity. And the ICP-AES quantified the lowest iron content that could be detected by MRI as 1.56~1.8 pg/cell. This study showed that the cationic SPIO could be directly used to label ADSCs, which could then inductively differentiate into nerve and be imaged by in vitro MRI, which would exhibit important guiding significance for the further in vivo MRI towards animal models with neurodegenerative disorders.

The labeling of stem cells by superparamagnetic iron oxide nanoparticles modified with PEG/PVP or PEG/PEI.

Poly(ethylene glycol) (PEG) and poly(vinyl pyrrolidone) (PVP) co-modified superparamagnetic iron oxide nanoparticles (SPIONs) (PEG/PVP-SPIONs), and PEG and poly(ethylene imine) (PEI) co-modified SPIONs (PEG/PEI-SPIONs) synthesized by thermal decomposition have been used as magnetic resonance imaging (MRI) contrast agents to label adipose-derived stem cells (ADSCs). Efficient cell labeling was achieved after incubation with PEG/PVP-SPIONs and PEG/PEI-SPIONs for 12h, and the MRI of labeled cells was evaluated. The cell viability tests showed the low cytotoxicity of PEG/PVP-SPIONs and PEG/PEI-SPIONs. The cellular iron content incubated with PEG/PVP-SPIONs at a concentration of 25 µg/ml was 6.96 pg/cell, the cellular iron contents incubated with PEG/PEI-SPIONs at concentrations of 12 and 25 µg/ml were 20.16, 35.4 pg/cell, respectively. The SPIONs were located predominantly in the intracellular vesicles. The cellular iron oxide uptake was significantly high after incubation with PEG/PEI-SPIONs as compared with the commercial iron oxide agents (Feridex, Feridex@PLL, Resovist and Resovist@PLL) reported. This work demonstrates that PEG/PEI-SPIONs are the competent agents for the labeling of ADSCs.