Imaging Features of Symptomatic MCA Stenosis in Patients of Different Ages: A Vessel Wall MR Imaging Study

BACKGROUND AND PURPOSE

The prevalence of intracranial artery stenosis is high in Asian people. This study aimed to investigate whether there are differences in the imaging features of symptomatic MCA stenosis in patients of different ages using vessel wall MR imaging.

MATERIALS AND METHODS

We retrospectively reviewed the data of consecutive patients with unilateral MCA stenosis based on a prospectively established vessel wall MR imaging data base between January 2017 and December 2018. According to age, the patients were divided into the young group (18-45 years of age) and the middle-aged and elderly group (older than 45 years of age).

RESULTS

Overall, 131 patients with unilateral MCA stenosis were included (45.8% in the young group and 54.2% in the middle-aged and elderly group). Middle-aged and elderly patients had a higher prevalence of hypertension (P = .01) and diabetes (P = .05). The lesion length (P < .0001), proportion of circular involvement (P = .006), and proportion of circular enhancement (P = .03) were higher in the young group than in the middle-aged and elderly group. The analysis of the atherosclerotic subgroup showed that compared with middle-aged and elderly patients, young patients had longer lesions (P = .002). The atherosclerotic-versus-nonatherosclerotic subgroup analysis showed that the maximal wall thickness in the patients with atherosclerosis was larger than that of patients without it (P = .002).

CONCLUSIONS

Compared with the middle-aged and elderly group, young patients with MCA stenosis tended to have longer lesions and more circular wall involvement and circular enhancement, which may indicate the differences in underlying vascular pathophysiologic and developmental mechanisms in symptomatic MCA stenosis.

Pulp Stem Cell-Mediated Functional Pulp Regeneration

The preservation of vital dental pulp with vasculature and nerve components remains one of the most significant challenges in modern dentistry. Due to the immense potential for neurovascularization, mesenchymal stem cell (MSC) transplantation has shown emerging promise in regenerative medicine and dental translational practice. Actually, pulp mesenchymal stem cells, including postnatal dental pulp stem cells (from permanent teeth) and stem cells from human exfoliated deciduous teeth, possess unique properties based on their origins from neural crest or glial cells. Furthermore, they reside in a neurovascular niche and have the potential for neurogenesis, angiogenesis, and neurovascular inductive activity. According to current pulp regeneration strategies, pulp stem cell-mediated approaches to regeneration have demonstrated convincing evidence that they can rebuild the complex histologic structure of native pulp in situ with highly organized physiologic patterns or even achieve de novo regeneration of complete dental pulp tissues. More importantly, recent clinical studies emphasized in situ neurovascularization outcomes in successful regeneration of vitalized pulp via pulp stem cell transplantation. In this review, we summarize recent breakthroughs in pulp stem cell-mediated pulp regeneration, emphasizing the crucial achievement of neurovascularization. This functional pulp regeneration represents an innovative and promising approach for future regenerative endodontics.

Assessment of wall shear stress in the common carotid artery of healthy subjects using 3.0-tesla magnetic resonance

BACKGROUND

Wall shear stress (WSS) has been proven to play a critical role in the formation and development of atherosclerotic plaques. Measurement of WSS in vivo is significant for the clinical assessment of atherosclerosis.

PURPOSE

To assess the magnitude and distribution of local WSS in the common carotid artery (CCA) in vivo using 3.0T magnetic resonance (MR).

MATERIAL AND METHODS

The common carotid artery of eight healthy volunteers was studied using a cine phase-contrast MR sequence. A three-dimensional paraboloid model was applied to fit the velocity profiles, and the WSS values were calculated. The cross-sectional area, average flow velocity, maximum velocity, and flow rate were also obtained.

RESULTS

Mean WSS was 0.850 +/- 0.195 (range 0.132-3.464) N/m(2) for the common carotid arteries; the spatial and temporal distribution and change of WSS were displayed. During a cardiac cycle, the mean velocity was 22.8 +/- 3.5 (16.9-28.3) cm/s, blood flow rate 8.03+/-1.45 (5.73-10.72) ml/s, and luminal vessel area 34.94+/-7.06 (24.25-49.01) mm(2).

CONCLUSION

Local WSS values in CCAs can be measured using 3.0T MR imaging combined with image-processing techniques. Intersubject variations were found in the distribution and magnitude of wall shear stress as well as in the flow profile pattern in CCAs, which may be caused by different vessel morphologies.

[The study on in vivo erythropoietin gene transfer for treatment of renal anemia in animal model]

To explore the possibility of gene therapy to renal anemia, the receptor mediated erythropoietin (EPO) gene transfer in vivo had been tested. EPO gene was inserted to an EBV replicon expression vector to form the plasmid pEPO, Renal anemia rat had been induced by feeding with adenine, and 450 micrograms of the pEPO was delivered by perfusion into the rat peripheral circulation in the form of soluble DNA/galactosylate histone complex. 13 days after injection, the number of peripheral red cells was counted and the concentration of hemoglobin was measured. The results demonstrated that symptom of anemia had been significantly improved(P < 0.01), when compared with that of the control test. (the red cell number was 492 vs 409, and the hemoglobin was 11.4 vs 9.1).

[Different stages of magnetic resonance in cerebral cysticercosis and its clinical significance]

We report the MR findings in 52 cases of cerebral cysticercosis, divided into four stages according to MR findings and clinical features. 1. Active stage 915 cases was characterized by the presence of small cysts in the brain parenchymal. On T1-WI images, the cysticercus appeared as hypointensity vesicle with a high-intensity nodule that corresponded to the scolex; 2. Degenerative stage was characterized by the presence of small cysticercotic cerebral abscess (6 cases) or infarctions (1 case), arachnoiditis with hydrocephalus (2 cases), cysticercus racemose (1 case); 3. Inactive stage was characterized by calcification (10 cases), and fibrosis in the basal meninges with hydrocephalus (2 cases); 4. Mixed stage (14 cases). We conclude that MR is more sensitive than CT in the diagnosis of active and degenerative stages of the parasite, whereas it is less sensitive for the inactive stage.

[Image changes of hemoglobin in acute and hyperacute intracranial hematoma during hyperintensive magnetic resonance]

36 intracranial hematomas between one hour and 7 days were imaged by using magnetic resonance at 1.0 T, with T1-and T2-weighted spin-echo pulse sequences. Characteristic intensity patterns were observed in the evolution of the hematomas, which could be staged as hyperacute (less than 24 hours) and acute (greater than 1 day and less than 7 days). Hyperacute stage could be subdivided into three phases, and hyperacute hematomas were characterized by hypointensity-mild hyperintensity-isointensity on T1-weighted images. Acute stage could be subdivided into three phases, and acute hematomas were characterized by hypointensity (DHB)-hyperintensity (MHB in intact RBC)-hyperintensity (free, undilute MHB in lysed RBC) on T1-weighted images. Acute hematomas were characterized by hypointensity (DHB)-obviously hypointensity (DHB + MHB in intact RBC)-hypointensity (DHB + free, undilute MHB in lysed RBC) on T2-weighted images. Different mechanisms were proposed for these characteristic intensity patterns of hyperacute and acute hematomas.