Retinal perfusion is linked to cognition and brain MRI biomarkers in Black Americans

INTRODUCTION

We investigated whether retinal capillary perfusion is a biomarker of cerebral small vessel disease and impaired cognition among Black Americans, an understudied group at higher risk for dementia.

METHODS

We enrolled 96 Black Americans without known cognitive impairment. Four retinal perfusion measures were derived using optical coherence tomography angiography. Neurocognitive assessment and brain magnetic resonance imaging (MRI) were performed. Multiple linear regression analyses were performed.

RESULTS

Lower retinal capillary perfusion was correlated with worse Oral Symbol Digit Test (P < = 0.005) and Fluid Cognition Composite scores (P < = 0.02), but not with the Crystallized Cognition Composite score (P > = 0.41). Lower retinal perfusion was also correlated with higher free water and peak width of skeletonized mean diffusivity, and lower fractional anisotropy (all P < 0.05) on MRI (N = 35).

DISCUSSION

Lower retinal capillary perfusion is associated with worse information processing, fluid cognition, and MRI biomarkers of cerebral small vessel disease, but is not related to crystallized cognition.

[Clinical phenotypic and genotypic analysis of 5 pediatric patients with β-ketothiolase deficiency]

Objective: To summarize the clinical and genetic characteristics of children with β-ketothiolase deficiency (BKTD). Methods: The clinical characteristics, biochemical, markers detected by tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC/MS), as well as the variants in ACAT1 gene among 5 children with BKTD in Children's Hospital of Chongqing Medical University between October 2018 and December 2022 were retrospectively analyzed. Results: The onset age of the disease in 5 patients (4 males and 1 female) ranged from 9.7 to 28.0 months. During the acute phase, severe metabolic acidosis was observed with a pH of 6.9-7.1, as well as hypoglycaemia (2.3-3.4 mmol/L) and positive urinary ketone bodies (+-++++). Blood levels of methylcrotonyl carnitine, methylmalonyl carnitine and malonyl carnitine were 0.03-0.42, 0.34-1.43 and 0.83-3.53 μmol/L respectively and were significantly elevated. Urinary 2-methyl-3-hydroxybutyric acid was 22-202 and 3-hydroxybutyric acid was 4-6 066, both were higher than the normal levels. Methylcrotonylglycine was mild elevated (0-29). The metabolites detected by MS/MS and GC/MS were significantly reduced after treatment. Analysis of ACAT1 gene mutation was performed in 5 children. Most variants were missense (8/9). Four previously unreported variants were identified: c.678G>T (p.Trp226Cys), c.302A>G (p.Gln101Arg), c.627_629dupTGA (p.Asn209_Glu210insAsp) and c.316C>T (p.Gln106Ter), the first 2 variants were predicted to be damaging by SIFT, PolyPhen-2 and Mutation Taster software. c.316C>T (p.Gln106Ter) is a nonsense variant. Conclusions: β-ketothiolase deficiency is relatively rare, lacks specific clinical manifestations, however severe metabolic acidosis, hypoglycemia, and ketosis during the acute onset were consistent findings. Missense mutations in the ACAT1 gene are common genetic causes of β-ketothiolase deficiency.

[Pelvic exenteration for late complications of radiation-induced pelvic injury: a preliminary study]

Objective: To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury. Methods: This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded. Results: The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100-6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions: TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.

Amyloid and tau pathology are associated with cerebral blood flow in a mixed sample of nondemented older adults with and without vascular risk factors for Alzheimer's disease

Identification of biomarkers for the early stages of Alzheimer's disease (AD) is an imperative step in developing effective treatments. Cerebral blood flow (CBF) is a potential early biomarker for AD; generally, older adults with AD have decreased CBF compared to normally aging peers. CBF deviates as the disease process and symptoms progress. However, further characterization of the relationships between CBF and AD risk factors and pathologies is still needed. We assessed the relationships between CBF quantified by arterial spin-labeled magnetic resonance imaging, hypertension, APOEε4, and tau and amyloid positron emission tomography in 77 older adults: cognitively normal, subjective cognitive decline, and mild cognitive impairment. Tau and amyloid aggregation were related to altered CBF, and some of these relationships were dependent on hypertension or APOEε4 status. Our findings suggest a complex relationship between risk factors, AD pathologies, and CBF that warrants future studies of CBF as a potential early biomarker for AD.

Shape-Aware 3D Small Vessel Segmentation with Local Contrast Guided Attention

The automated segmentation and analysis of small vessels from in vivo imaging data is an important task for many clinical applications. While current filtering and learning methods have achieved good performance on the segmentation of large vessels, they are sub-optimal for small vessel detection due to their apparent geometric irregularity and weak contrast given the relatively limited resolution of existing imaging techniques. In addition, for supervised learning approaches, the acquisition of accurate pixel-wise annotations in these small vascular regions heavily relies on skilled experts. In this work, we propose a novel self-supervised network to tackle these challenges and improve the detection of small vessels from 3D imaging data. First, our network maximizes a novel shape-aware flux-based measure to enhance the estimation of small vasculature with non-circular and irregular appearances. Then, we develop novel local contrast guided attention(LCA) and enhancement(LCE) modules to boost the vesselness responses of vascular regions of low contrast. In our experiments, we compare with four filtering-based methods and a state-of-the-art self-supervised deep learning method in multiple 3D datasets to demonstrate that our method achieves significant improvement in all datasets. Further analysis and ablation studies have also been performed to assess the contributions of various modules to the improved performance in 3D small vessel segmentation. Our code is available at https://github.com/dengchihwei/LCNetVesselSeg.

Efficacy and Safety of High-Dose Vitamin C Combined with Total Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer (HCCSC R02 Study)

PURPOSE/OBJECTIVE(S)

Forpatients with locally advanced rectal cancer (LARC), the standard treatment is fluoropyrimidine (FU) -based neoadjuvant chemoradiotherapy (NCRT) combined with curative surgery. The CAO/ARO/AIO-04 trial and FORWARC trial reported that the addition of oxaliplatin to FU -based NCRT contributed to improve pathologic complete response (pCR), nevertheless, increased the acute therapeutic toxicity. Some studies showed that vitamin C (VitC) had potential benefits on anti-tumor therapy and anti-inflammatory response. Therefore, we conducted this HCCSC R02 study to explore the efficacy and safety of adding a high-dose intravenous VitC to mFOLFOX6/XELOX -based NCRT in LARC.

MATERIALS/METHODS

HCCSCR02 study was designed as a prospective, single-center phase II trial, which including pts aged 18-75 years with stage II/III rectal adenocarcinoma, distance from anus ≤12cm. The enrollment criteria included: staged with MRI as cT3/cT4 or cN1/2, or mesorectal fascia involvement (MRF+), or difficult to preserve the anus. Patients with glucose-6-phosphate dehydrogenase enzyme(G6PD) deficiency were excluded. Pelvic intensity modulated radiation therapy (IMRT) was given in 45-50.4Gy/25-28 fractions. Concurrently, two cycles of chemotherapy (mFOLFOX6 or XELOX) were administered during IMRT, as well as intravenous VitC (24g) delivered daily after the end of each radiation therapy. Additional 2-3 cycles of mFOLFOX6 / XELOX were adopted between the completion of radiotherapy and surgery. The primary endpoint was pCR rate. The secondary endpoints included radiation-related toxicities, overall survival (OS) and disease-free survival (DFS). This study is still recruiting.

RESULTS

From May 15, 2021 to Feb 8, 2023, 19 pts were recruited and finished all the scheduled NCRT, of which the proportion of cT4, cT3, cN2, cN1 were 31.6%, 63.2%, 52.6%, 36.8%, respectively. In addition, 10 pts (52.6%) were diagnosed as MRF+ initially, and 8 pts (42.1%) had a lower primary tumor(≤5cm) who were considered difficult for anal preservation before NCRT. All subjects enrolled were confirmed to be proficient mismatch repair (pMMR). As a result, 18 pts underwent a total mesorectal excision (TME) all with R0-resection, and 8 pts were evaluated as pCR (44.4%, 8/18, confidence interval: 0.246-0.663), 11 as major pathological response rate (MPR) (61.6%, 11/18), respectively. The anus preservation rate in patients with lower diseases was 87.5% (7/8). One case accepted a watch-and-wait strategy because of clinical complete response (cCR). Overall, grade 3 toxicities were observed in 4 pts, including 3 leucopenia (15.8%, 3/19), 2 neutropenia (10.5%, 2/19) and 1 diarrhea (5.3%, 1/19). No grade 4 adverse event was observed.

CONCLUSION

The addition of high-dose VitC to the mFOLFOX6/XELOX-based NCRT in LARC showed a promising pCR, well tolerance, particularly low rate of diarrhea, thus warrants further investigation.

CLINICAL TRIAL INFORMATION

NCT04801511.

[BCS1Neonatal growth retardation and lactic acidosis initiated by novel mutation sites in L gene]

This study aims to analyze the clinical characteristics and genetic variations of two cases with developmental delay and lactic acidosis in a family, and to explore the relationship between genetic variations and clinical features. A retrospective analysis was conducted on the clinical characteristics of two siblings with developmental delay and lactic acidosis who were treated at the Neonatal Department of Children's Hospital of Chongqing Medical University in May 2019 and December 2021, respectively. Whole-exome sequencing was used to detect genetic variations in the affected children. Homology modeling of the BCS1L protein was performed to analyze the structural and functional changes of the protein. The correlation between genetic variations and clinical phenotypes was analyzed. The results showed that the main clinical features of the two affected children in this family were manifestations of mitochondrial respiratory chain complex Ⅲ deficiency, including prematurity, developmental delay, respiratory failure, lactic acidosis, cholestasis, liver dysfunction, renal tubular lesions, coagulation dysfunction, anemia, hypoglycemia, hypotonia, and early death. Whole-exome sequencing revealed a novel deletion mutation c.486_488delGGA (p.E163del) and a novel missense mutation c.992C>T (p.T331I) in the BCS1L gene. Structural analysis of the homology modeling showed that the compound heterozygous mutation had a significant impact on protein function. In conclusion, the novel mutation site c.992C>T (p.T331I) in the BCS1L gene is a "likely pathogenic" mutation, and the compound heterozygous mutation is closely related to the phenotype of mitochondrial respiratory chain complex Ⅲ deficiency.

[Prognostic value of perioperative change of neutrophil elastase and myeloperoxidase in coronary circulation on perioperative myocardial injury and clinical outcome of patients underwent surgical valve replacement]

Objective: To investigate the clinical value of observing perioperative changes of myeloperoxidase (MPO) and neutrophil elastase (NE) in coronary artery circulation in patients underwent valve replacement surgery. Methods: This perspective cohort study was performed in patients who underwent valvular surgery in Nanjing Drum Tower Hospital and Fuwai Hospital from June 2021 to June 2022. Patients were divided into perioperative myocardial injury group and age-, sex- and type of cardiac procedure-matched non-perioperative myocardial injury control group in the ratio of 1∶1. Perioperative myocardial injury was defined as cardiac troponin T (cTnT)>0.8 μg/L on the first postoperative day (POD), and the cTnT level on the second POD increased by more than 10% compared with the cTnT level on the first POD. During the operation, blood samples were collected from the coronary sinus before clamping ascending aorta, and within 5 minutes after de-clamping ascending aorta. Then, the levels of MPO and NE on coronary sinus were continuously measured. The death, severe ventricular arrhythmia, pneumonia, re-intubation, repeat cardiac surgery, extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP), continuous renal replacement therapy (CRRT), mechanical ventilation time and the duration of intensive care unit (ICU) were recorded. The levels of MPO and NE and the incidence of clinical outcomes were compared between the myocardial injury group and the control group. The independent risk factors of myocardial injury were analyzed by multivariate logistic regression. Results: A total of 130 patients were enrolled, aged (60.6±7.6) years old, with 59 males (45.4%). There were 65 patients in the myocardial injury group and 65 patients in the control group. During hospitalization, there was no death, ECMO, IABP and CRRT cases in both groups. Compared with the control group, the incidence of severe ventricular arrhythmia (13.8%(9/65) vs. 3.1%(2/65), P=0.03), pneumonia (20.0%(13/65) vs. 3.1%(2/65), P=0.03), re-intubation (6.2%(4/65) vs. 0, P=0.04) was significantly higher in myocardial injury group. The mechanical ventilation time (16.8(10.7, 101.7) h vs. 7.5(4.7, 15.1) h, P<0.01), and the duration of ICU (3.7(2.7, 18.9) vs. 2.7(1.8, 6.9)d, P<0.01) were significantly longer in myocardial injury group compared with the control group. There was no significant difference in the levels of MPO and NE in coronary sinus blood between the two groups before aortic clamping (all P>0.05). However, MPO ((551.3±124.2) μg/L vs. (447.2±135.9) μg/L, P<0.01) and NE ((417.0±83.1)μg/L vs. (341.0±68.3)μg/L, P<0.01) after 5 min aortic de-clamping were significantly higher in myocardial injury group than in the control group. Multivariate logistic regression analysis showed that the levels of NE (OR=1.02, 95%CI: 1.01-1.02, P<0.01), MPO (OR=1.00, 95%CI: 1.00-1.01, P=0.02) and mechanical ventilation time (OR=1.03, 95%CI: 1.01-1.06, P=0.02) were independent risk factors of myocardial injury in patients after surgical valvular replacement. Conclusion: Perioperative myocardial injury is related poor clinical outcomes, perioperative NE and MPO in coronary artery circulation are independent risk factors of perioperative myocardial injury in patients undergoing valve replacement surgery.

[Observational study on perioperative outcomes of pelvic exenteration]

Objective: To investigate the surgical indications and perioperative clinical outcomes of pelvic exenteration (PE) for locally advanced, recurrent pelvic malignancies and complex pelvic fistulas. Methods: This was a descriptive study.The indications for performing PE were: (1) locally advanced, recurrent pelvic malignancy or complex pelvic fistula diagnosed preoperatively by imaging and pathological examination of a biopsy; (2)preoperative agreement by a multi-disciplinary team that non-surgical and conventional surgical treatment had failed and PE was required; and (3) findings on intraoperative exploration confirming this conclusion.Contraindications to this surgical procedure comprised cardiac and respiratory dysfunction, poor nutritional status,and mental state too poor to tolerate the procedure.Clinical data of 141 patients who met the above criteria, had undergone PE in the Sixth Affiliated Hospital of Sun Yat-sen University from January 2018 to September 2022, had complete perioperative clinical data, and had given written informed consent to the procedure were collected,and the operation,relevant perioperative variables, postoperative pathological findings (curative resection), and early postoperative complications were analyzed. Results: Of the 141 included patients, 43 (30.5%) had primary malignancies, 61 (43.3%) recurrent malignancies, 28 (19.9%) complex fistulas after radical resection of malignancies,and nine (6.4%)complex fistulas caused by benign disease. There were 79 cases (56.0%) of gastrointestinal tumors, 30 cases (21.3%) of reproductive tumors, 16 cases (11.3%) of urinary tumors, and 7 cases (5.0%) of other tumors such mesenchymal tissue tumors. Among the 104 patients with primary and recurrent malignancies, 15 patients with severe complications of pelvic perineum of advanced tumors were planned to undergo palliative PE surgery for symptom relief after preoperative assessment of multidisciplinary team; the other 89 patients were evaluated for radical PE surgery. All surgeries were successfully completed. Total PE was performed on 73 patients (51.8%),anterior PE on 22 (15.6%),and posterior PE in 46 (32.6%). The median operative time was 576 (453,679) minutes, median intraoperative blood loss 500 (200, 1 200) ml, and median hospital stay 17 (13.0,30.5)days.There were no intraoperative deaths. Of the 89 patients evaluated for radical PE surgery, the radical R0 resection was achieved in 64 (71.9%) of them, R1 resection in 23 (25.8%), and R2 resection in two (2.2%). One or more postoperative complications occurred in 85 cases (60.3%), 32 (22.7%)of which were Clavien-Dindo grade III and above.One patient (0.7%)died during the perioperative period. Conclusion: PE is a valid option for treating locally advanced or recurrent pelvic malignancies and complex pelvic fistulas.

Older Adults With Higher Blood Pressure Variability Exhibit Cerebrovascular Reactivity Deficits

BACKGROUND

Elevated blood pressure (BP) variability is predictive of increased risk for stroke, cerebrovascular disease, and other vascular brain injuries, independent of traditionally studied average BP levels. However, no studies to date have evaluated whether BP variability is related to diminished cerebrovascular reactivity, which may represent an early marker of cerebrovascular dysfunction presaging vascular brain injury.

METHODS

The present study investigated BP variability and cerebrovascular reactivity in a sample of 41 community-dwelling older adults (mean age 69.6 [SD 8.7] years) without a history of dementia or stroke. Short-term BP variability was determined from BP measurements collected continuously during a 5-minute resting period followed by cerebrovascular reactivity during 5-minute hypocapnia and hypercapnia challenge induced by visually guided breathing conditions. Cerebrovascular reactivity was quantified as percent change in cerebral perfusion by pseudo-continuous arterial spin labeling (pCASL)-MRI per unit change in end-tidal CO2.

RESULTS

Elevated systolic BP variability was related to lower whole brain cerebrovascular reactivity during hypocapnia (ß = -0.43 [95% CI -0.73, -0.12]; P = 0.008; adjusted R2 =.11) and hypercapnia (ß = -0.42 [95% CI -0.77, -0.06]; P = 0.02; adjusted R2 = 0.19).

CONCLUSIONS

Findings add to prior work linking BP variability and cerebrovascular disease burden and suggest BP variability may also be related to prodromal markers of cerebrovascular dysfunction and disease, with potential therapeutic implications.

[Correlation between cerebral oxygen saturation monitored by near-infrared spectroscopy during operation and risk of stroke after acute type A aortic dissection surgery]

Objective: Near-infrared spectroscopy (NIRS) is widely used for intraoperative cerebral oxygen saturation monitoring in patients with acute type A aortic dissection. This study aimed to investigate the correlation between NIRS-derived oxygen saturation and risk of postoperative stroke. Methods: This study included 193 patients with acute type A aortic dissection undergoing emergency surgery and elective unilateral cerebral perfusion via the right axillary artery at the Department of Cardiothoracic Surgery, Nanjing Drum Tower Hospital, Nanjing, China, from 2018 to 2020. NIRS was used for intraoperative cerebral oxygen saturation monitoring, and the basal values and the lowest values of cerebral oxygen saturation during deep hypothermic circulatory arrest (DHCA) were recorded. The patients were divided into no-stroke group (n=178, 92.2%) and stroke group (n=15, 7.8%) according to the absence or presence of postoperative stroke. The differences in preoperative, operative and postoperative clinical differences between the two groups were compared, and the relationship between the lowest cerebral oxygen saturation value and the change in cerebral oxygen saturation value ((base-lowest)/basal) and postoperative stroke were analyzed. Results: The proportion of preoperative atrial fibrillation (6.7% vs. 0.6%, P=0.026), and the proportion of preoperative hypotension (26.7% vs. 9.0%, P=0.031) were significantly higher in the stroke group than no-stroke group. There were no differences in the surgical approach between the two groups. Cardiopulmonary bypass (CPB) time ((256.1±84.8) h vs.(217.8±58.4) h, P=0.020), postoperative mechanical ventilation time ((139.3±172.8) h vs. (35.6±45.6) h, P<0.001) were significantly longer in stroke group as compared to no-stroke group. Incidence of postoperative tracheotomy (20.0% vs. 1.1%, P<0.001), acute kidney injury (73.3% vs. 30.3%, P=0.001) and continuous renal replacement therapy (46.7% vs. 11.8%, P<0.001) as well as mortality (20.0% vs. 5.1%, P=0.022) were significantly higher in the stroke group than in non-stroke group. There was no significant difference in the basal NIRS value and the lowest NIRS value during DHCA between the two groups. Patients in the stroke group had a significantly greater intraoperative change rate of right NIRS as compared to no-stroke group (15.2%±15.7% vs. 9.2%±7.0%, P=0.006). Conclusions: NIRS is valuable for monitoring cerebral oxygen saturation during acute type A aortic dissection surgery, and the rate change of NIRS during operation correlates significantly with postoperative stroke.

Selective vulnerability of medial temporal regions to short-term blood pressure variability and cerebral hypoperfusion in older adults

Blood pressure variability is an emerging risk factor for stroke, cognitive impairment, and dementia, possibly through links with cerebral hypoperfusion. Recent evidence suggests visit-to-visit (e.g., over months, years) blood pressure variability is related to cerebral perfusion decline in brain regions vulnerable to Alzheimer's disease. However, less is known about relationships between short-term (e.g., < 24 hours) blood pressure variability and regional cerebral perfusion, and whether these relationships may differ by age. We investigated short-term blood pressure variability and concurrent regional cerebral microvascular perfusion in a sample of community-dwelling older adults without history of dementia or stroke and healthy younger adults. Blood pressure was collected continuously during perfusion MRI. Cerebral blood flow was determined for several brain regions implicated in cerebrovascular dysfunction in Alzheimer's disease. Elevated systolic blood pressure variability was related to lower levels of concurrent cerebral perfusion in medial temporal regions: hippocampus (β = -.60 [95% CI -.90, -.30]; p < .001), parahippocampal gyrus (β = -.57 [95% CI -.89, -.25]; p = .001), entorhinal cortex (β = -.42 [95% CI -.73, -.12]; p = .009), and perirhinal cortex (β = -.37 [95% CI -.72, -.03]; p = .04), and not in other regions, and in older adults only. Findings suggest a possible age-related selective vulnerability of the medial temporal lobes to hypoperfusion in the context of short-term blood pressure fluctuations, independent of average blood pressure, white matter hyperintensities, and gray matter volume, which may underpin the increased risk for dementia associated with elevated BPV.

The effectiveness and safety of liraglutide in treating overweight/obese patients with polycystic ovary syndrome: a meta-analysis

PURPOSE

The purpose of this study is to evaluate the effectiveness and safety of liraglutide/liraglutide + metformin in overweight/obese women with polycystic ovary syndrome (PCOS).

METHODS

The related literatures published until April 2021 were searched in PubMed, Cochrane Library, MEDLINE and EmBase.

RESULTS

Six randomized controlled trials of 127 related articles were obtained through searching. Three articles compared liraglutide with metformin, and four articles compared liraglutide combined with metformin with metformin. Our meta-analysis suggests that liraglutide was superior to metformin only in weight loss [MD = - 2.74, 95% CI (- 4.29, - 1.18), P = 0.0006]. Compared with metformin group, the combination group had significant advantages in weight loss [MD = - 3.81, 95% CI (- 5.16, - 2.46), P < 0.001], BMI [MD = - 2.59, 95% CI (- 3.12, - 2.07), P < 0.001], waist circumference [MD = - 6.26, 95% CI (- 7.79, - 4.72), P < 0.001], fasting blood glucose [MD = - 0.59, 95% CI (- 0.74, - 0.44), P < 0.001] and fasting insulin [MD = - 1.52, 95% CI (- 2.69, - 0.35), P = 0.01], while the incidence of adverse reactions was relatively high [RR = 2.91, 95% CI (1.55, 5.46), P = 0.00009].

CONCLUSION

The present results indicate that liraglutide and metformin have the similar effects in the treatment of overweight/obese PCOS patients. Liraglutide combined with metformin is more effective than metformin in improving PCOS, but it is necessary to master the correct medication method to reduce the occurrence of adverse reactions.

[Ultrastructural features of the corneal epithelium with micromolecular compound J2 in the corneal allograft of rats using atomic force microscopy]

Objective: To study the ultrastructural features of the corneal epithelium in the corneal allograft of rats with micromolecular compound J2. Methods: An experimental study. Primarily cultured corneal epithelial cells of rats were used. Mononuclear cells (MNCs) by density gradient centrifugation were assigned into the experimental group [MNCs (2 ml)+corneal epithelial cells+J2], control group [MNCs (2 ml)+corneal epithelial cells] and blank group (corneal epithelial cells). Quantity of CD80 expression was obtained by flow cytometry after coculture. Amplitude and height images were obtained by tapping mode atomic force microscopy (AFM) with a scan rate of 2 Hz and an integral gain of 0.3 to 0.5. Statistical analysis of Ra, Rq, Rvm and Rt was performed using the single-factor analysis of variance, and P value was calculated. Results: There were obvious differences in the ultrastructure measured by AFM among groups. Ra was 86.75±12.60 in the experimental group, 120.23±12.11 in the control group, and 61.94±10.62 in the blank group (F=306.92, P<0.01). Rq was 102.53±9.45, 138.30±10.13, and 91.96±7.25, respectively, in the three groups (F=361.85, P<0.01). Rvm was -42.21±14.22, -67.36±10.89, and -32.18±19.01, respectively (F=72.22, P<0.01). Rt was 437.32±15.66, 495.32±13.96, and 339.92±11.22, respectively (F=1634.26, P<0.01). The one way analysis of variance showed significant differences in these parameters among groups. Conclusions: Corneal epithelial cells of rats activated by MNCs had higher CD80 expression, but the expression became decreased with micromolecular compound J2. The ultrastructure of the corneal epithelium became coarser after MNCs activation, and the number of protrusions increased significantly. The ultrastructural changes were alleviated by J2.(Chin J Ophthalmol, 2021, 57: 608-613).

[The incidence and related factors of coronary events among 40-49 years old patients undergoing cardiac thoracotomy without preoperative CAG]

Objective: To investigate the long-term incidence of coronary events and related factors in patients undergoing cardiac thoracotomy without preoperative coronary angiography (CAG). Methods: This was a retrospective study. The clinical data of patients, aged between 40 and 49 years old, who underwent cardiothoracic surgery, including heart valve surgery, congenital heart disease surgery, cardio great vessels surgery and other non-coronary artery disease (CAD) surgery, in Nanjing Drum Tower Hospital from December 2009 to May 2017, were enrolled. Patients with suspected CAD, or patients with coronary CTA defined calcified coronary arteries received CAG examination prior operation, and the rest patients did not receive routine CAG examinations. The patients who did not receive routine CAG examinations were followed up by telephone. The primary endpoints include death related to coronary arteries, coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI). The secondary endpoints include the new onset angina, clinically diagnosed CAD or receiving the first and second prevention for CAD. The other outcome events included cardiac death and all-cause mortality. The primary and secondary endpoints were all regarded as coronary events. The patients without preoperative CAG were divided into two groups: the positive group and the negative group, according to the incidence of coronary events during follow-up. Clinical data were compared between the two groups. Results: A total of 952 patients were included. The age was (45.2±2.7) years old, 406(42.65%) patients were male. Preoperative CAG was performed in 73 patients, among whom 9 (12.32%) patients underwent simultaneous CABG. Among the 879 cases who did not undergo coronary angiography before the operation, 18(2.05%) died during perioperative period (hospitalization and within 30 days after discharge). The patients were followed up for (61.6±25.8) months, and 28(3.25%) patients were lost to follow up. During long-term follow up, there were no fatal cases due to severe coronary events and no cases of CABG or PCI. Only 4.41% (38/861) patients had the secondary endpoints, namely the occasional onset of atypical angina. The incidence rate of the long-term coronary events, all-cause mortality and cardiac death were 4.41% (38/861), 1.16% (10/861), 0.46% (4/861) during long-term follow-up. The prevalence of hypertension was significantly higher in positive group than negative group (34.21% (13/38) vs. 20.89% (164/785), P=0.045). Conclusions: It is feasible not to perform preoperative CAG examination for non-CAD patients aged 40-49 years who will undergo cardiac thoracotomy. However, we need to be aware the risk of coronary events in the patients complicating with risk factors of CAD, such as hypertension.

Prevalence and factors associated with motoric cognitive risk syndrome in community-dwelling older Chinese: a cross-sectional study

BACKGROUND AND PURPOSE

A recently proposed pre-dementia syndrome, motoric cognitive risk (MCR) syndrome, is characterized by cognitive complaints and slow gait, and increases the risk of dementia and mortality. The aim of the present study was to explore the prevalence of and factors associated with MCR syndrome in elderly community-dwelling Chinese subjects.

METHODS

The Ningbo Community Study on Aging recruited 953 Chinese community-dwelling participants aged ≥ 65 years from November 2016 to March 2017. Handgrip, Five-Times-Sit-to-Stand (FTSS) test time and body composition, as well as comprehensive geriatric evaluation, were measured as potentially independent factors associated with MCR syndrome.

RESULTS

The prevalence of MCR syndrome was 12.8% in men and 12.6% in women, and high prevalence of MCR syndrome was not associated with age or sex. Multiple logistic regression analysis by sex showed that a 1-SD increase in FTSS test time in males and females was associated with 45% (95% confidence intervals, 19-76; P < 0.01) and 20% (95% confidence intervals, 9-33; P < 0.01) higher risk of having MCR syndrome, respectively, whereas handgrip strength was inversely correlated with MCR syndrome in males [odds ratio (OR), 0.91; P = 0.02] but not females (P = 0.06). Moreover, the relationship of arm fat mass and MCR syndrome was statistically significant in both sexes (OR, 1.69-1.77), but leg fat mass was only associated with MCR syndrome (OR, 1.56; P = 0.02) in men.

CONCLUSIONS

Handgrip, FTSS test time and body composition were associated in a sex-specific manner with MCR syndrome in elderly community-dwelling Chinese subjects. Our results on MCR syndrome are novel and should be considered as important information in future studies.

[Nursing care of one case of incontinent dermatitis complicated with sacrococcygeal pressure ulcer]

A 67-year-old female patient with incontinent dermatitis complicated with sacrococcygeal pressure ulcer was admitted to our unit in November 2017. The wound was treated with a new dressing based on the concept of wet healing, management of exudation, prevention of infection to promote wound healing. Meanwhile, the fecal incontinence was properly treated with colostomy bag combined with disposable negative pressure drainage device to avoid fecal contamination and aggravation of pressure ulcer. Incontinent dermatitis was treated with wound protective powder and wound protective film. After 14 days of treatment, the wound of pressure ulcer was reduced and the incontinent dermatitis was cured.

The Interpeduncular Angle: A Practical and Objective Marker for the Detection and Diagnosis of Intracranial Hypotension on Brain MRI

BACKGROUND AND PURPOSE

Classic findings of intracranial hypotension on MR imaging, such as brain stem slumping, can be variably present and, at times, subjective, potentially making the diagnosis difficult. We hypothesize that the angle between the cerebral peduncles correlates with the volume of interpeduncular cistern fluid and is decreased in cases of intracranial hypotension. We aimed to investigate its use as an objective assessment for intracranial hypotension.

MATERIALS AND METHODS

Brain MRIs of 30 patients with intracranial hypotension and 30 age-matched controls were evaluated by 2 fellowship-trained neuroradiologists for classic findings of intracranial hypotension and the interpeduncular angle. Group analysis was performed with a Student t test, and receiver operating characteristic analysis was used to identify an ideal angle threshold to maximize sensitivity and specificity. Interobserver reliability was assessed for classic findings of intracranial hypotension using the Cohen κ value, and the interpeduncular angle, using the intraclass correlation.

RESULTS

The interpeduncular angle had excellent interobserver reliability (intraclass correlation coefficient value = 0.833) and was significantly lower in the intracranial hypotension group compared with the control group (25.3° versus 56.3°; P < .001). There was significant correlation between the interpeduncular angle and the presence of brain stem slumping (P < .001) and in cases with ≥3 classic features of intracranial hypotension (P = .01). With a threshold of 40.5°, sensitivity and specificity were 80% and 96.7%, respectively.

CONCLUSIONS

The interpeduncular angle is a sensitive and specific measure of intracranial hypotension and is a reliably reproducible parameter on routine clinical MR imaging.

Full Sibling Testing Based on NGS-SNP Genotyping Method and IBS Strategy

Abstract

Objective To evaluate the effectiveness of single nucleotide polymorphism （SNP） genoty-ping in combination with identity by state （IBS） strategy in full sibling testing. Methods Thirty-five blood samples were collected from a four-generation family. Ninety autosomal SNPs were genotyped using Precision ID Identity Panel. The distribution of IBS scores for full siblings and other relationships were calculated and compared. The relationships were determined using Fisher discriminant function and threshold method, respectively. Results Based on family members and previous research, 44, 30, 111, 71 and 1 000 pairs of full siblings （FS）, grandparent-grandchild （GG）, uncle/aunt-nephew/niece （UN）, first cousins （FC） and unrelated individuals （UI） were obtained, respectively. The average IBS scores were 148, 130, 132, 124 and 120, respectively. Except for the GG and UN pairs, the distribution differences among the other relationships had statistical significance （P<0.05）. The false rates of Fisher discriminant function to determine relationships were 1.3%, 22.3%, 17.0% and 38.7% for FS, GG, UN and FC, respectively. Based on the simulation data, the thresholds t₁=128 and t₂=141 were recommended to determine full sibling relationships （the false rate ≤0.05%）. Conclusion The 90 SNP genetic markers included in the Precision ID Identity Panel meet the testing requirements for full sibling relationships. The threshold method based on IBS has a relatively lower false rate and is more flexible.

[Treatment experience of cardiac rupture in patients with acute myocardial infarction]

Objective: To analyze the treatment results of cardiac rupture in patients with acute myocardial infarction (AMI) . Method: Clinical data of 6 with cardiac rupture after AMI, who were hospitalized in our hospital from June 2015 to June 2017, were retrospectively analyzed,and the clinical manifestations, methods of treatment and outcomes were investigated. Results: Cardiac function classification was Killip class Ⅱin all patients. There were 3 massive anterior wall myocardial infarction, 2 anterior wall myocardial infarction,and 1 inferior myocardial infarction. There were 4 patients with ventricular septal defect, 1 patient with rupture of papillary muscle,and 1 patient with left ventricular free wall rupture.All patients received continuous infusion of vasoactive medicines and treated with intra-aortic balloon pump(IABP), 2 patients (1 patient accepted operative treatment,and 1 patient received conservative treatment) were treated with extracorporeal membrane oxygenation (ECMO), mechanical ventilation,and continuous renal replacement therapy(CRRT).Three patients received surgical repair,1 case was supported by IABP, 1 case supported by ECMO,CRRT,and IABP,and 1 case did not use IABP or ECMO post operation. All 3 surgically treated patients recovered successfully and were discharged from hospital.Meanwhile, in the other 3 patients treated conservatively, 2 patients died in the hospital and 1 patient was discharged according to own will. Conclusion: On the basis of vasoactive medicines and IABP, surgery repair is a feasible option for cardiac rupture patients secondary to AMI,and ECMO may improve the perioperative state in these patients.

7-Tesla MRI of the brain in a research subject with bilateral, total knee replacement implants: Case report and proposed safety guidelines

Recently, the first 7-T MR system was approved for clinical use in the United States. Unfortunately, relatively few metallic implants have undergone testing to determine if they are acceptable or pose hazards to research subjects and patients at this ultra-high-field strength. Therefore, in lieu of not performing a research or clinical MRI exam at 7-T, the supervising physician may make a decision to scan the individual with an untested metallic implant based on an analysis of the risks vs. the benefits. We present a case report of a research subject with bilateral, total knee replacement implants that safely underwent MRI of the brain at 7-T and provide guidelines for healthcare professionals to follow in order to ensure safety in research subjects or patients with metallic implants referred for 7-T scans.

Clinical 7 T MRI: Are we there yet? A review about magnetic resonance imaging at ultra-high field

In recent years, ultra-high field MRI (7 T and above) has received more interest for clinical imaging. Indeed, a number of studies have shown the benefits from the application of this powerful tool not only for research purposes, but also in realms of improved diagnostics and patient management. The increased signal-to-noise ratio and higher spatial resolution compared with conventional and high-field clinical scanners allow imaging of small anatomical detail and subtle pathological findings. Furthermore, greater spectral resolution achieved at ultra-high field allows the resolution of metabolites for MR spectroscopic imaging. All these advantages have a significant impact on many neurological diseases, including multiple sclerosis, cerebrovascular disease, brain tumors, epilepsy and neurodegenerative diseases, in part because the pathology can be subtle and lesions small in these diseases, therefore having higher signal and resolution will help lesion detection. In this review, we discuss the main clinical neurological applications and some technical challenges which remain with ultra-high field MRI.

Abstract WP60: Kernel Spectral Regression and Neural Networks Enable Regional Detection of Hemorrhagic Transformation on Multi-Modal MRI for Acute Ischemic Stroke

Purpose: Hyperperfusion detected on arterial spin labeling (ASL) cerebral blood flow (CBF) images acquired after acute ischemic stroke (AIS) onset has been shown to be significantly associated with development of intracerebral hemorrhage. ASL data is often too noisy for accurate voxel-based analysis alone. The purpose of this study was to develop a machine learning model for the voxel-based detection of tissue at risk for hemorrhagic transformation (HT) utilizing multiple MRI modalities.

Materials and Methods: The present study utilized clinical MRI and ASL image data acquired from 67 AIS patients shortly after endovascular therapy. A novel regional cuboid sampling framework was developed for machine learning training, in which local cuboids were extracted from the CBF map, DWI, FLAIR, and TSE images before being matched with GRE-based manually drawn bleed groundtruth delineations. Kernel spectral regression (KSR) uses the eigenvectors of the graph representation to reveal low dimensional structure in high dimensional data. A two-layer feed-forward neural network was then built with 10 neurons in the sigmoid hidden layer and trained with scaled conjugate gradient backpropagation to classify cuboid inputs into likelihood of HT.

Results: The proposed multimodal regional framework reached an accuracy of 80.59 ± 3% in detecting hemorrhage with KSR on our dataset (better than a voxel-based prediction on CBF with 72.80 ± 5% accuracy). Using the neural network training, the framework reached an improved accuracy of 95.1% ± 0.6%. Figure 1 shows how the regions with high likelihood of hemorrhage match well with the manually drawn regions in the reference GRE map.

Conclusion: Kernel spectral regression and neural networks can provide more accurate detection of tissues at risk for HT. Although CBF can inform AIS patient clinical outcome, the addition of multi-modal MRI data into the regional cuboid framework substantially improves the voxel-based HT detection accuracy.

Abstract WP419: Visualization and Evaluation of Human Lenticulostriate Arteries Using High-resolution Black-blood T1-weighted Turbo-spin Echo (TSE) at 3T and 7T

Purpose: Cerebral small vessel disease (SVD) leads to cognitive decline and is the most common vascular cause of dementia. Small arteries, particularly the lenticulostriate arteries (LSAs), are known to be involved in silent strokes. We aim to image the LSAs using a high-resolution 3D black blood T1 weighted (T1w) turbo-spin echo (TSE) sequence with variable flip angles (VFA) at both 3T and 7T.

Methods: Four healthy volunteers (1 female, 26±3 years) were scanned on both Siemens 3T Prisma and 7T Terra MRI systems using a 32-channel head coil. A 3D T1w TSE sequence with VFA was chosen for small vessel imaging with inherent excellent contrast between vessels and tissue due to good blood suppression properties. Black blood images were acquired with optimized imaging parameters at 3T (voxel size = 0.26x0.26x0.5 mm 3 interpolated, slices=166, TE/TR = 12/1000 ms, ETL=41, scan time = 9:05 min) and 7T (voxel size = 0.5 mm 3 isotropic, slices=288, TE/TR = 13/1430 ms, ETL = 40, scan time = 11:55 min). Contrast to noise ratio (CNR) was calculated to compare image quality between 3T and 7T.

Results and Discussion: Fig. 1 displays the LSAs using minimum intensity projection across 25 mm slices from a subject at 3T and 7T. Improved delineation of LSAs, especially distal regions, can be appreciated at 7T compared to 3T. Comparison of CNR for blood in the LSAs vs. the adjacent white matter between 3T and 7T (CNR: 9.1 vs. 15.5, 6.7 vs. 15.4, and 4.3 vs. 8.9 for the stem, middle, and distal regions, respectively) further demonstrated that LSAs imaged at 7T have better contrast in general and especially in the distal regions as noted by the colored arrows.

Conclusion: This preliminary study demonstrated the feasibility for visualizing LSAs in the human brain using high-resolution T1w TSE at 3T and 7T. Specifically, TSE at 7T provides better delineation of LSAs with better contrast between vessels and tissue. Our findings suggest this 7T TSE technique could be a promising imaging marker of cerebral small vessel diseases.

[Expression profiles and clinical implication of plasma chemokines in patients with Stanford type A aortic dissection]

Objective: To explore the plasma chemokines expressions and related clinical implication in patients with Stanford type A aortic dissection (AD). Methods: We retrospectively analyzed the data of 65 patients with Stanford type A aortic dissection, hypertensive patients and 11 healthy subjects admitted in our department from October 2013 to December 2014, they were divided into four groups: NH-CON group (11 healthy subjects), H-AD group (29 AD patients with hypertension), NH-AD group (21 AD patients without hypertension), and H-CON group (14 hypertension patients). Four plasma samples from AD patients and 4 plasma samples from healthy subjects were collected randomly with random numbers table, and the levels of different chemokines were examined by protein array analysis. Then, plasma levels of chemokines including macrophage inflammatory protein 1β(MIP-1β), epithelial neutrophil activating peptide 78(ENA-78), interleukin 16(IL-16), interferon inducible protein 10(IP-10) and FMS-like tyrosine kinase 3(Flt-3) ligand were analyzed by luminex. Pearson analysis was used to determine the correlations between the chemokines and serum C reactive protein (CRP) levels. Results: Plasma levels of MIP-1β(34.0(29.3, 47.2) ng/L vs. 51.0(28.2, 80.7) ng/L, P<0.05) and ENA-78(110.5(59.1, 161.4) ng/L vs. 475.7(299.3, 837.3) ng/L, P<0.05) were significantly lower in H-AD group, while plasma IL-16 level was significantly higher in H-AD group(54.7(16.3, 187.8) ng/L vs. 17.5(11.9, 20.8) ng/L, P<0.05) than in H-CON group. Plasma levels of MIP-1β(48.3(26.4, 62.1) ng/L, P<0.05) were significantly lower in H-AD patients than in NH-AD patients. Plasma level of ENA-78 was significantly lower in NH-AD group than in NH-CON group (95.0(58.0, 155.0) ng/L vs. 257.7(85.2, 397.8) ng/L, P<0.05). The levels of IP-10 and Flt-3 ligand were similar among the 4 groups (all P>0.05). Pearson analysis showed that there were no correlation between MIP-1β(r(2)=0.01, P>0.05), ENA-78(r(2)=0.02, P>0.05), IL-16(r(2)=0.02, P>0.05), IP-10(r(2)=0.00, P>0.05), Flt-3 ligand(r(2)=0.02, P>0.05) and CRP levels in patients with Stanford type A aortic dissection. Conclusions: Lower plasma levels of MIP-1β and ENA-78 and higher plasma levels of IL-16 may associate with the occurrence and development of type A aortic dissection, but their concentrations are not correlated with serum CRP levels. There is no significant change on plasma levels of IP-10 and Flt-3 in the Stanford type A aortic dissection patients.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

Abstract WMP97: Regional Cerebral Oxygen Extraction is Elevated in Tissue at High Risk of Stroke in Pediatric Sickle Cell Disease

Introduction: Children with sickle cell disease (SCD) are at high risk of stroke. Hemispheric oxygen extraction fraction (OEF) is a predictor of stroke in adults with carotid occlusion, but OEF has not been evaluated as a predictor of stroke in children with SCD.

Hypothesis: OEF is elevated in SCD children compared to controls within a region at high risk of stroke as defined by an infarct heat-map created from a separate retrospective SCD cohort.

Methods: A prospective MRI study enrolled 37 children aged 5-21: 17 with SCD and no stroke, 12 with SCD and silent infarcts (median infarct volume=0.3ml), and 8 sibling controls. None were on transfusions or had overt stroke history. Voxel-wise OEF was measured using an asymmetric spin echo sequence. In a separate retrospective cohort of 67 SCD children with overt and silent stroke, infarct regions on FLAIR were manually outlined and coregistered to an average T1 map to create an infarct heat-map (Fig A) which was used to define a “high risk” ROI (defined by >3% infarct density). This ROI was aligned to individual OEF maps from the prospective cohort (Fig B, average OEF map). OEF within the “high risk” ROI was compared between SCD children and controls; and between SCD children with and without infarction using Mann Whitney U tests.

Results: The infarct heat-map from the retrospective cohort (Fig A) and the average OEF map from the prospective SCD cohort (Fig B) demonstrate striking co-localization of infarct density and elevated OEF. Within the “high risk” ROI, OEF was higher in SCD children compared to controls (39% [36, 46] vs. 23% [22, 27], p<0.0001 (Fig C). OEF within this “high risk” ROI did not differ between SCD children with and without infarcts (40% [38, 47] vs. 38% [35, 46], p=0.6).

Conclusion: OEF in SCD children is elevated in the internal borderzone, a region with high stroke risk in SCD. Regional OEF may be a marker of cerebral metabolic stress that could be exploited to stratify stroke risk in this vulnerable population.

Abstract 35: Transfusion Relieves Cerebral Metabolic Stress in Children with Sickle Cell Disease

Introduction: Transfusions (Tx) are the mainstay of stroke prevention in children with sickle cell disease (SCD), but the pathophysiology conferring this neuroprotection is not well understood.

Hypothesis: Tx relieves cerebral metabolic stress by improving arterial oxygen content, thereby lowering chronically-elevated cerebral blood flow (CBF) and oxygen extraction fraction (OEF) in children with SCD at risk for stroke.

Methods: Children with SCD on chronic Tx therapy underwent two brain MRIs with measurement of CBF via pseudocontinuuous arterial spin labeling and OEF via asymmetric spin echo sequence within 24 hours of exchange Tx. To determine how Tx may reduce regions of elevated OEF, we set absolute OEF thresholds (45, 47.5, 50%) and compared tissue volumes above each threshold pre- and post-Tx using nonparametric paired statistics.

Results: Twelve children with SCD (6-21 yrs) underwent MRIs. Tx raised Hb and lowered CBF and OEF (Figure), suggesting that elevated CBF and OEF may be markers of metabolic stress relieved by Tx. While CBF correlates with age in healthy children, pre-Tx CBF correlation with age was lost (τ= -0.42, p=0.07), but regained post-Tx (τ= -0.76, p=0.001). Also, absolute change in OEF diminished with increasing age (τ=. -0.75, p=0.003). Regions with very high OEF were found in the periventricular white matter, a common area of infarcts in SCD (Figure, average OEF maps pre- and post-Tx). Tx reduced the volume of these brain regions defined by all three OEF thresholds (Table), suggesting that Tx reduces brain regions at high risk for stroke.

Conclusion: Tx in SCD children improves arterial oxygen content by increasing Hb, allowing CBF and OEF to fall, thus relieving metabolic stress globally and regionally. The absolute change in OEF correlates with age, suggesting that the efficacy of Tx may be age-dependent.

Abstract T P297: Arterial Spin Labeled MRI Quantifies Cerebral Blood Flow Changes with Blood Pressure from Acute to Subacute Stroke

Background: Hemodynamic interventions, such as blood pressure (BP) manipulation, are often utilized to optimize perfusion of the ischemic territory. Scant data support theoretical effects of permissive hypertension or BP reduction, yet arterial-spin labeled (ASL) MRI may chronicle quantitative cerebral blood flow (CBF) changes. We used serial ASL to measure CBF changes associated with hemodynamic interventions, based on arterial occlusion site and collaterals.

Methods: Serial ASL acquired in 148 consecutive cases of acute ischemic stroke at a single center during a 3-year period. A pseudo-continuous ASL pulse sequence with background suppressed 3D GRASE (gradient and spin echo) readout with 4 post-labeling delays was used, with normalization of quantitative CBF on a standard neurovascular template. CBF values and relative changes were measured in the affected hemisphere and in discrete regions of infarct core and collateral territories.

Results: 148 cases (median age 68 years (IQR 62-82), 73 women) were studied. Overall, CBF (ml/100g/min) was related to age (r=-0.40, p<0.001) but not gender (male: 39±9.7, female: 40.6±8.2; r=.05, p=NS). Serial studies were obtained in 126 cases, including 2 studies in 91, 3 in 32, and 4 in 3. Median time to 1 st , 2 nd , 3 rd , and 4 th ASL study was 11.3, 39.7, 140.7, and 121.3 hrs and median CBF at these timepoints was 39.9 (IQR 28-48); 42.2 (IQR 29-52); 47.1 (IQR 36-56); and 35.6 (IQR 34-41). Average changes in CBF from study 1 to 2, 2 to 3, 3 to 4 were +2.2; +3.4; -14.8. Average CBF ratio between leptomeningeal and perforating MCA regions was 1.1. The correlation of initial delta CBF (study 1 to 2) with initial delta BP (1 to 2) was r=-0.1, p=NS. Average delta CBF/delta mmHg SBP was 0.25. At studies 1 and 2, lower BP was related to higher CBF (r=-0.148, p=0.102). Overall, delta BP was not linked with CBF (r=0.002, p=NS) or delta CBF (r=-0.108, p=NS). For those with low initial CBF (<40), positive delta BP was strongly associated with lower CBF at study 2 (r=-0.552, p=0.006).

Conclusions: Blood pressure modification, permissive or interventional, may differentially affect CBF in the ischemic core and collateral regions. ASL provides a novel method for non-invasive mapping of serial changes in absolute CBF quantification in the ICU and beyond.

Mutational analysis of podocyte genes in children with sporadic steroid-resistant nephrotic syndrome

Recent studies have demonstrated that mutations in 4 podocyte genes, NPHS1, NPHS2, CD2AP, and WT1, are associated with the pathogenesis of steroid-resistant nephrotic syndrome (SRNS). Systematic investigation of all 4 genes for sporadic SRNS in China has not been performed. We examined 10 Chinese children with sporadic SRNS who showed no response to immunosuppressive agents and 20 SRNS controls who exhibited a response to prolonged steroid or immunosuppressive treatment and achieved complete remission. We analyzed mutations in the 4 podocyte genes, NPHS1, NPHS2, CD2AP, and WT1. Mutational analysis was performed using polymerase chain reaction and direct sequencing. Of the 10 SRNS children who showed no response to immunosuppressive agents, the compound heterozygous NPHS1 mutations 2677A>G (T893A) and *142T>C were identified in 1 patient, while a heterozygous mutation in WT1, 1180C>T (R394W), was found in another patient. Of the 20 SRNS children showing complete remission who responded to prolonged steroid therapy or immunosuppressive agents, 4 heterozygous NPHS1 mutations, 928G>A, IVS8+30C>T, IVS21+14G>A, and IVS25-23C>T, were identified in 4 patients and a heterozygous CD2AP mutation, IVS7-135G>A, was identified in 1 patient. Our results indicate the necessity of genetic examination for mutations in podocyte genes in Chinese SRNS children who show no response to immunosuppressive agents.

Highly efficient beamline and spectrometer for inelastic soft X-ray scattering at high resolution

The design, construction and commissioning of a beamline and spectrometer for inelastic soft X-ray scattering at high resolution in a highly efficient system are presented. Based on the energy-compensation principle of grating dispersion, the design of the monochromator-spectrometer system greatly enhances the efficiency of measurement of inelastic soft X-rays scattering. Comprising two bendable gratings, the set-up effectively diminishes the defocus and coma aberrations. At commissioning, this system showed results of spin-flip, d-d and charge-transfer excitations of NiO. These results are consistent with published results but exhibit improved spectral resolution and increased efficiency of measurement. The best energy resolution of the set-up in terms of full width at half-maximum is 108 meV at an incident photon energy tuned about the Ni L3-edge.

Voxelwise spectral diffusional connectivity and its applications to Alzheimer's disease and intelligence prediction

Human brain connectivity can be studied using graph theory. Many connectivity studies parcellate the brain into regions and count fibres extracted between them. The resulting network analyses require validation of the tractography, as well as region and parameter selection. Here we investigate whole brain connectivity from a different perspective. We propose a mathematical formulation based on studying the eigenvalues of the Laplacian matrix of the diffusion tensor field at the voxel level. This voxelwise matrix has over a million parameters, but we derive the Kirchhoff complexity and eigen-spectrum through elegant mathematical theorems, without heavy computation. We use these novel measures to accurately estimate the voxelwise connectivity in multiple biomedical applications such as Alzheimer's disease and intelligence prediction.

Abstract T P29: Arterial-Spin Labeled MRI After Endovascular Stroke Therapy: Validation of a Novel Scale to Quantify the Degree and Heterogeneity of Reperfusion

Background: The degree of reperfusion in acute stroke is a key predictor of clinical outcome, yet validation of a noninvasive imaging technique such as arterial spin-labeled MRI (ASL) that can quantify both hypo- and hyperperfusion is needed.

Methods: Consecutive series of endovascular therapy for acute stroke and ASL-MRI within 36 hours after treatment start during a 3-year period were analyzed. Reperfusion on DSA was scored with TICI and mTICI (2b definitions of 2/3 and ½, respectively). ASL cerebral blood flow was graded with a scale analogous to mTICI (0=none, 1=< ½, 2=>½, 3=complete) separately for hypo- and hyperperfusion based on occlusion site, yet blinded to TICI/mTICI results.

Results: 64 patients (mean age 67.7 ± 13.9 years; 53% women; median baseline NIHSS 15 (2-38)) had ASL acquired within 36 hours (median 7.07 hours (2.69-33.08)) from start of IV thrombolysis or thrombectomy over a 3-year period. 31/64 (48%) patients received IV tPA before endovascular therapy. DSA revealed 32 M1, 18 ICA, 10 M2, and 4 basilar occlusions. After endovascular treatment, TICI0/mTICI0 (6%), TICI1/mTICI1 (2%), TICI2a/mTICI2a (30%), TICI2a/mTICI2b (22%), TICI2b/mTICI2b (39%) and TICI3/mTICI3 (2%) results were noted. ASL revealed hypoperfusion (0 (19%); 1 (59%); 2 (14%); 3 (8%)) and hyperperfusion (0 (69%); 1 (27%); 3 (5%)). 7 combined patterns of hypo- and hyperperfusion were noted on ASL, all unrelated to baseline clinical variables. ASL mTICI hypoperfusion strongly correlated with DSA mTICI (R=-0.77, p<0.001) and TICI (R=-0.71, p<0.001). ASL hyperperfusion was noted only with TICI2a/mTICI2a (9%), TICI2a/mTICI2b (14%), TICI2b/mTICI2b (9%) and was more common with increased time from DSA to ASL (p=0.017).

Conclusions: ASL hypoperfusion within 36 hours of acute stroke therapy strongly correlates with reperfusion scores on DSA, providing a novel means to accurately quantify degree of reperfusion. ASL hyperperfusion, concomitant with hypoperfusion, affects a substantial number of cases, predominantly affecting the TICI2a/mTICI2b reperfusion category on DSA.

Association study of vascular endothelial growth factor gene polymorphisms with ectopic pregnancy in Chinese women

OBJECTIVE

The purpose of this study is to evaluate potential associations between vascular endothelial growth factor (VEGF) gene polymorphisms and ectopic pregnancy (EP) in Chinese women.

MATERIALS AND METHODS

This was a case-control study wherein 192 women with a history of EP were compared to 210 post-menopausal controls with two pregnancies and no EP for the genotyping of VEGF polymorphisms. Genotyping of the VEGF gene polymorphisms at -460C/T, -1 154G/A, -2578C/A and +936C/T were performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

No significant differences were found in genotype and allele distributions of the -460C/T, +936C/T polymorphisms between cases and controls. Compared with the -1154G/G genotype, the -1154(A/A+G/A) genotype could significantly reduce the risk of developing EP. For the -2578C/A polymorphism, the A/A+C/A geno- type could significantly decrease the risk of developing EP, compared with the C/C genotype. The haplotype analysis suggested that the TAA (VEGF -460/-1154/-2578) and CAA haplotypes could significantly decrease the risk of developing EP compared with the haplotype of TGC.

CONCLUSION

The -1154A or -2578A alleles of VEGF gene could significantly decrease the risk of EP and might be po- tentially protective factors for EP development in Chinese women.

Measurement of cerebral white matter perfusion using pseudocontinuous arterial spin labeling 3T magnetic resonance imaging--an experimental and theoretical investigation of feasibility

PURPOSE

This study was aimed to experimentally and numerically investigate the feasibility of measuring cerebral white matter perfusion using pseudocontinuous arterial spin labeling (PCASL) 3T magnetic resonance imaging (MRI) at a relatively fine resolution to mitigate partial volume effect from gray matter.

MATERIALS AND METHODS

The Institutional Research Ethics Committee approved this study. On a clinical 3T MR system, ten healthy volunteers (5 females, 5 males, age = 28 ± 3 years) were scanned after providing written informed consent. PCASL imaging was performed with varied combinations of labeling duration (τ = 1000, 1500, 2000, and 2500 ms) and post-labeling delay (PLD = 1000, 1400, 1800, and 2200 ms), at a spatial resolution (1.56 x 1.56 x 5 mm(3)) finer than commonly used (3.5 x 3.5 mm(2), 5-8 mm in thickness). Computer simulations were performed to calculate the achievable perfusion-weighted signal-to-noise ratio at varied τ, PLD, and transit delay.

RESULTS

Based on experimental and numerical data, the optimal τ and PLD were found to be 2000 ms and 1500-1800 ms, respectively, yielding adequate SNR (~2) to support perfusion measurement in the majority (~60%) of white matter. The measurement variability was about 9% in a one-week interval. The measured white matter perfusion and perfusion ratio of gray matter to white matter were 15.8-27.5 ml/100ml/min and 1.8-4.0, respectively, depending on spatial resolution as well as the amount of deep white matter included.

CONCLUSION

PCASL 3T MRI is able to measure perfusion in the majority of cerebral white matter at an adequate signal-to-noise ratio by using appropriate tagging duration and post-labeling delay. Although pixel-wise comparison may not be possible, region-of-interest based flow quantification is feasible.

GABA estimation in the brains of children on the autism spectrum: measurement precision and regional cortical variation

(1)H magnetic resonance spectroscopy ((1)H MRS) and spectral editing methods, such as MEGA-PRESS, allow researchers to investigate metabolite and neurotransmitter concentrations in-vivo. Here we address the utilization of (1)H MRS for the investigation of GABA concentrations in the ASD brain, in three locations; motor, visual and auditory areas. An initial repeatability study (5 subjects, 5 repeated measures separated by ~5days on average) indicated no significant effect of reference metabolite choice on GABA quantitation (p>0.6). Coefficients of variation for GABA+/NAA, GABA+/Cr and GABA+/Glx were all of the order of 9-11%. Based on these findings, we investigated creatine-normalized GABA+ ratios (GABA+/Cr) in a group of (N=17) children with autism spectrum disorder (ASD) and (N=17) typically developing children (TD) for Motor, Auditory and Visual regions of interest (ROIs). Linear regression analysis of gray matter (GM) volume changes (known to occur with development) revealed a significant decrease of GM volume with Age for Motor (F(1,30)=17.92; p<0.001) and Visual F(1,16)=14.41; p<0.005 but not the Auditory ROI (p=0.55). Inspection of GABA+/Cr changes with Age revealed a marginally significant change for the Motor ROI only (F(1,30)=4.11; p=0.054). Subsequent analyses were thus conducted for each ROI separately using Age and GM volume as covariates. No group differences in GABA+/Cr were observed for the Visual ROI between TD vs. ASD children. However, the Motor and Auditory ROI showed significantly reduced GABA+/Cr in ASD (Motor p<0.05; Auditory p<0.01). The mean deficiency in GABA+/Cr from the Motor ROI was approximately 11% and Auditory ROI was approximately 22%. Our novel findings support the model of regional differences in GABA+/Cr in the ASD brain, primarily in Auditory and to a lesser extent Motor but not Visual areas.

Abstract WP41: Peri-Procedural Arterial Spin Labeling and Dynamic Susceptibility contrast Perfusion in Detection of Cerebral Blood Flow in Patients with Acute Ischemic Syndrome

Purpose: To investigate the potential clinical value and diagnostic performance of arterial spin-labeled (ASL) and dynamic susceptibility contrast (DSC) perfusion in detection of cerebral blood flow (CBF) changes before and after endovascular recanalization in patients with acute ischemic syndrome (AIS).

Methods: This retrospective study was performed using MR examinations between 2010-2012. Inclusion criteria were: patients with AIS who underwent endovascular recanalization and acquisition of both ASL and DSC before and after revascularization. ASL CBF and multiparametric DSC perfusion maps were qualitatively evaluated for image quality, presence of hypo or hyperperfusion and location of perfusion abnormality. Lesion segmentation for infarct core (ADCb >550) and hypoperfused area (TMax > 4 sec) was performed on DSC. rCBF was calculated using a regions-of-interest (ROI) method in the infarction core and hypoperfused areas using coregistered ASL and DSC images. Core and hypoperfused rCBF ROI’s were used for paired pre- and post-treatment intermodality comparisons. Interobserver and intermodality agreement was evaluated by Kappa test. T-test and Spearman correlation coefficients were calculated for ASL and DSC rCBF values.

Results: Twenty-five patients were met our inclusion criteria. Five studies were rated non-diagnostic, resulting in a total of 45 pair of DSC-ASL for comparison. ASL and DSC agreed on type of perfusion abnormality in 32 of 45 cases (71%) and location of the perfusion abnormality in 36 of 45 cases (80%). The image quality of ASL was lower than DSC, resulting in interobserver variability for the type (k =0.45) and location (k=0.56) of perfusion abnormality. ASL was unable to show any type of perfusion abnormality in 11% of patients. In patients with successful recanalization, hyperperfusion (rCBF> 1) was detected in 100% on DSC and 47% on ASL. ASL showed prolonged arterial transit effects in 58% of successfully recanalized patients.

Conclusion: ASL is moderately consistent with DSC for detection of cerebral blood flow changes in patients with AIS. Qualitative and quantitative differences exist between two modalities, in particular in respect to detection of hyperperfusion in successfully recanalized patients.

Abstract TP41: Arterial Spin-Labeled Perfusion MRI with Multi-Delay: Expanding Beyond CBF in Acute Ischemic Stroke

Background: Arterial spin-labeled (ASL) perfusion MRI can measure cerebral blood flow (CBF), yet the prolonged delays of collateral perfusion in acute ischemic stroke may impose limitations. Multiparametric maps of perfusion, including transit times and cerebral blood volume (CBV), may reveal important hemodynamic features before CBF collapse. We implemented a novel multi-delay ASL sequence to investigate multiparametric perfusion changes in acute stroke.

Methods: Consecutive acute ischemic stroke patients admitted during an 8-month period were evaluated with pseudo-continuous ASL on Siemens 1.5 T and 3 T scanners within 12 hours of symptom onset. ASL was acquired using a 4-delay pCASL protocol with background suppressed 3D GRASE (postlabeling delay (PLD)=1.5/2/2.5/3s, FOV=22cm, matrix=64x64, 16x8mm slices, rate-2 GRAPPA, TE=22ms, 8 pairs of tag and control for each delay, total scan time 4min). After motion correction, arterial transit time (ATT), CBF, and arterial CBV (aCBV) maps were generated from the 4 PLDs.

Results: A total of 161 ASL multi-delay perfusion MRI studies were performed in 130 acute ischemic stroke patients (mean age was 71±18 years and 56% were female). Repeated multi-delay ASL or serial studies were acquired in 19 cases, including 11 cases with 2 MRIs, 7 with 3, and 1 with 6 MRIs, depicting multiparametric blood flow changes after treatment. Correlation of multi-delay ASL (4 PLDs) and DSC MRI CBF asymmetry measures in MCA stroke patients (when available) was r=0.785 (p<0.001) and r=0.683 (p=0.003) for CBV measures with limited correlation for ATT.

Conclusions: Multidelay ASL with 4 PLDs is feasible in the setting of acute stroke, providing multiparametric perfusion measures (CBF, CBV, ATT) of blood flow changes with treatment.

Abstract 1905: Arterial Spin-Labeled MRI of Leptomeningeal Collateral Perfusion in Acute Ischemic Stroke

Background: Leptomeningeal collaterals and associated cortical perfusion downstream from a proximal arterial occlusion or stenosis are potent predictors of outcome in acute stroke. Arterial spin-labeled (ASL) MRI may depict delayed arterial transit effects (DATE) of these collaterals and cerebral blood flow (CBF), utilizing noninvasive techniques without the use of contrast. We conducted a prospective validation study of ASL DATE and CBF as biomarkers of leptomeningeal collateral perfusion compared to digital subtraction angiography (DSA) and dynamic susceptibility contrast (DSC) perfusion MRI in acute ischemic stroke.

Methods: Consecutive anterior circulation acute ischemic stroke patients admitted during a 1-year period were evaluated with pseudo-continuous ASL, DSA and DSC perfusion MRI within 12 hours of symptom onset. ASL DATE extent was scored using a 3-point scale and angiographic collaterals on the DSA graded using the ASITN/SIR collateral score. ASL CBF and DSC CBF maps were co-registered to derive comparative ROI statistics on perfusion in the symptomatic territory. ASL CBF lesions < 15 mL/100 g/min were used to measure DSC CBF values within coregistered ROIs.

Results: Among 39 patients meeting entry criteria, mean age was 66±19 years and 51% were male. All 39 patients were imaged with ASL and DSA, with DSC perfusion MRI in a subset of 27. Sites of vascular occlusion or stenosis were: terminal ICA - 10, M1 MCA - 20, M2 MCA - 5 and more distal MCA - 4. ASL DATE scores ranged from 0-2, with a median of 1. DSA collateral grade ranged from 0-4, with a median of 2. Overall, there was strong correlation (r=0.702, p<0.001) between the ASL and DSA measures of leptomeningeal collateral supply. In the downstream territory from these leptomeningeal collaterals, ASL CBF and DSC CBF maps both revealed hypoperfusion in regions that closely matched. Only limited correlation, however, was noted between exact ASL CBF and DSC CBF values within the co-registered ROIs.

Conclusions: ASL MRI provides an accurate, noninvasive measure of leptomeningeal collateral perfusion in acute ischemic stroke due to anterior circulation stenosis or occlusion. ASL CBF measures of collateral perfusion likely are arterially weighted, like DSA collateral grades, and unlike conventional DSC perfusion MRI CBF values.

Abstract 1910: Hyperperfusion in Acute Ischemic Stroke: Serial Arterial Spin-Labeled MRI of Reperfusion and Hemorrhagic Transformation

Background: Arterial spin-labeled (ASL) MRI facilitates repeated noninvasive evaluation of cerebral blood flow without the use of contrast. Hyperperfusion may be readily detected with ASL and serial imaging may therefore chronicle the dynamics of territorial perfusion from acute to chronic phases after stroke. We characterized hyperperfusion on ASL in a prospective series of acute ischemic stroke patients, describing the clinical correlates, time course and association with reperfusion hemorrhage.

Methods: A consecutive series of acute ischemic stroke patients admitted during a 1-year period were evaluated with pseudo-continuous ASL with background suppressed 3D GRASE (delay=2s, matrix=64x64; 26 slices, resolution 3.4x3.4x5mm, scan time 4min). Post-processed ASL CBF maps were visually inspected for detection of hyperperfusion. DSA measures of collaterals and reperfusion were scored when available and hemorrhagic transformation (HT) was graded on GRE in all 198 cases. Univariate and multivariate statistical analyses delineated clinical correlates, timing and other imaging features of hyperperfusion.

Results: Among 198 patients, mean age was 69.4±15.7 years and 48.5% were women. Among 77 with serial ASL MRI, interval from initial to follow-up MRI was median 25.0 (IQR 10.3-53.9) hours. Hyperperfusion was detected in 15/198 (7.6%) patients at baseline and 30/77 (39.0%) at follow-up. Trajectories included 7/77 (9.1%) with hyperperfusion at both baseline and follow-up and 38/77 (49.4%) showing hyperperfusion at any timepoint during admission. Hyperperfusion correlated with achievement of reperfusion among patients undergoing endovascular therapy (OR 6.5, 95% CI 1.82-23.25, p=0.018) and history of atrial fibrillation (OR 4.4, 95% CI 1.9-10.6, p<0.001). Analysis of the 42 cases with DSA revealed that hyperperfusion was most common in patients with poor collateral grade followed by more complete TICI reperfusion scores. Overall, HT affected 57/198 (28.8%), including 35/198 (17.7%) HI1, 11/198 (5.6%) HI2, 8/198 (4.1%) PH1 and 3/198 (1.5%) PH2. Multivariate analyses revealed that hyperperfusion at any timepoint was a potent predictor of HT (OR 52.6, 95%CI 12.4-222.6, p<0.001).

Conclusions: Hyperperfusion in acute ischemic stroke is frequently demonstrated by ASL MRI, providing novel insight on the dynamics of reperfusion and HT. Hyperperfusion increases the risk of HT 50-fold, likely due to autoregulatory loss. Poor collaterals and sudden reperfusion in vulnerable cases such as those with atrial fibrillation may herald hyperperfusion and HT.

Baseline CBF, and BOLD, CBF, and CMRO2 fMRI of visual and vibrotactile stimulations in baboons

Neurovascular coupling associated with visual and vibrotactile stimulations in baboons anesthetized sequentially with isoflurane and ketamine was evaluated using multimodal functional magnetic resonance imaging (fMRI) on a clinical 3-Tesla scanner. Basal cerebral blood flow (CBF), and combined blood-oxygenation-level-dependent (BOLD) and CBF fMRI of visual and somatosensory stimulations were measured using pseudo-continuous arterial spin labeling. Changes in stimulus-evoked cerebral metabolic rate of oxygen (CMRO(2)) were estimated using calibrated fMRI. Arterial transit time for vessel, gray matter (GM), and white matter (WM) were 250, 570, and 823 ms, respectively. Gray matter and WM CBF, respectively, were 107.8±7.9 and 47.8±3.8 mL per 100 g per minute under isoflurane, and 108.8±10.3 and 48.7±4.2 mL per 100 g per minute under ketamine (mean±s.e.m., N=8 sessions, five baboons). The GM/WM CBF ratio was not statistically different between the two anesthetics, averaging 2.3±0.1. Hypercapnia evoked global BOLD and CBF increases. Blood-oxygenation-level-dependent, CBF, and CMRO(2) signal changes by visual and vibrotactile stimulations were 0.19% to 0.22%, 18% to 23%, and 4.9% to 6.7%, respectively. The CBF/CMRO(2) ratio was 2.9 to 4.7. Basal CBF and fMRI responses were not statistically different between the two anesthetics. This study establishes a multimodal fMRI protocol to probe clinically relevant functional, physiological and metabolic information in large nonhuman primates.

Relating MEG measured motor cortical oscillations to resting γ-aminobutyric acid (GABA) concentration

The human motor cortex exhibits characteristic beta (15-30 Hz) and gamma oscillations (60-90 Hz), typically observed in the context of transient finger movement tasks. The functional significance of these oscillations, such as post-movement beta rebound (PMBR) and movement-related gamma synchrony (MRGS) remains unclear. Considerable animal and human non-invasive studies, however, suggest that the networks supporting these motor cortex oscillations depend critically on the inhibitory neurotransmitter γ-Aminobutyric acid (GABA). Despite such speculation, a direct relation between MEG measured motor cortex oscillatory power and frequency with resting GABA concentrations has not been demonstrated. In the present study, motor cortical responses were measured from 9 healthy adults while they performed a cued button-press task using their right index finger. In each participant, PMBR and MRGS measures were obtained from time-frequency plots obtained from primary motor (MI) sources, localized using beamformer differential source localization. For each participant, complimentary magnetic resonance spectroscopy (MRS) GABA measures aligned to the motor hand knob of the left central sulcus were also obtained. GABA concentration was estimated as the ratio of the motor cortex GABA integral to a cortical reference NAA resonance at 2 ppm. A significant linear relation was observed between MI GABA concentration and MRGS frequency (R(2)=0.46, p<0.05), with no association observed between GABA concentration and MRGS power. Conversely, a significant linear relation was observed between MI GABA concentration and PMBR power (R(2)=0.34, p<0.05), with no relation observed for GABA concentration and PMBR frequency. Finally, a significant negative linear relation between the participant's age and MI gamma frequency was observed, such that older participants had a lower gamma frequency (R(2)=0.40, p<0.05). Present findings support a role for GABA in the generation and modulation of endogenous motor cortex rhythmic beta and gamma activity.

Computed tomography-guided aspiration versus key-hole craniotomy for spontaneous putaminal haemorrhage: a prospective comparison of minimally invasive procedures

OBJECTIVES

To compare the effectiveness of two minimally invasive procedures, namely computed tomography-guided aspiration and the key-hole approach, in the neurosurgical management for spontaneous putaminal haemorrhage, and to explore the indications for the two approaches.

DESIGN

A multicentre, single-blinded controlled trial.

SETTING

Hospitals taking part in this trial and the sources for patients were from China. Among others, the hospitals involved in the interventions included: the Beijing Tiantan Hospital (of the Capital University of Medical Sciences), the General Hospital of People's Liberation Army, the Peking Union Hospital, and the Shanghai Huashan Hospital (of the Fudan University medical school).

PATIENTS

From September 2001 to November 2003, data were available for analysis from a total of 841 patients with spontaneous putaminal haemorrhage from 135 hospitals all over China (except Tibet, Hong Kong, Taiwan, and Macao). All follow-up data were for at least 3 months.

MAIN OUTCOME MEASURES

Mortality, Glasgow Coma Scale score, postoperative complications, Kanofsky Performance Scale score, and Barthel Index.

RESULTS

There were 563 patients who underwent computed tomography-guided aspiration, and 165 were treated by the key-hole approach. Respective mortality rates 1 month after the operation were 17.9% and 18.3%; at 3 months they were 19.4% and 19.4%. In those undergoing computed tomography-guided aspiration, mortality rates at 3 months after the operation were 28.2% in patients with Glasgow Coma Scale scores of 8 or below, as opposed to 8.2% in those with higher scores. This amounted to a 3.4-fold difference. In those treated by the key-hole approach, the corresponding rates were 30.2% and 7.6%, which amounted to a 4-fold difference. The corresponding mortality at 3 months in patients with complications was 3.9 times as great as in those without complications. In those with haematoma volumes of 70 mL or greater, it was 2.7 times as much as in those in whom the volumes below 30 mL. The postoperative complication rate of computed tomography-guided aspiration (23.7%) did not differ significantly from that in those having the key-hole approach (25.7%) [P=0.420].

CONCLUSIONS

Computed tomography-guided aspiration is not superior to the key-hole approach for treating spontaneous putaminal haemorrhage in terms of favourable outcomes, mortality, and morbidity. However, it could be the first-choice approach for those with bleeds of 50 mL or less, while the key-hole approach may be more suitable for those with larger haematomas.

Mesenchymal Stem Cells Genetically Modified with the Angiopoietin-1 Gene Enhanced Arteriogenesis in a Porcine Model of Chronic Myocardial Ischaemia

The direct injection by thoracoscope of mesenchymal stem cells (MSCs) that had been genetically modified to express angiopoietin-1 was investigated in a porcine model to determine their effect on arteriogenesis and the effectiveness of this technique. Chronic myocardial ischaemia was established using a thoracoscope to insert an ameroid constrictor around the left circumflex coronary artery. Six weeks after establishing the ischaemia, 20 pigs were randomly divided into three groups to receive injections by thoracoscope of either genetically-modified MSCs, unmodified MSCs or phosphate-buffered saline into the ischaemic border area. The injections were repeated 1 month later. The genetically modified MSCs were found to restore blood flow significantly more than the other observed treatments and immunohistochemical evaluation of arteriogenesis supported this finding. In conclusion, the injection of MSCs that had been genetically modified to express angiopoietin-1 improved arteriogenesis and increased collateral blood flow in the myocardial ischaemic area. Thoracoscope delivery of the injection was safe and minimally invasive.

Natural history of Canavan disease revealed by proton magnetic resonance spectroscopy (1H-MRS) and diffusion-weighted MRI

Canavan disease is a childhood leukodystrophy caused by mutations in the gene for human aspartoacylase ( ASPA), which leads to an abnormal accumulation of the substrate molecule N-acetyl-aspartate (NAA) in the brain. This study was designed to model the natural history of Canavan disease using MRI and proton magnetic resonance spectroscopy ( (1)H-MRS). NAA and various indices of brain structure (morphology, quantitative T1, fractional anisotropy, apparent diffusion coefficient) were measured in white and gray matter regions during the progression of Canavan disease. A mixed-effects statistical model was used to fit all outcome measures. Longitudinal data from 28 Canavan patients were directly compared in each brain region with reference data obtained from normal, age-matched pediatric subjects. The resultant model can be used to non-invasively monitor the natural history of Canavan disease or related leukodystrophies in future studies involving drug, gene therapy, or stem cell treatments.

Mild-onset presentation of Canavan's disease associated with novel G212A point mutation in aspartoacylase gene

We describe two sisters with a mild-onset variant of Canavan's disease who presented at age 50 and 19 months with developmental delay but without macrocephaly, hypotonia, spasticity, or seizures. Remarkably, both patients had age-appropriate head control, gross motor development, and muscle tone. There were very mild deficits in fine motor skills, coordination, and gait. Both sisters had a history of strabismus, but otherwise vision was normal. The older child showed evidence of mild cognitive and social impairment, whereas language and behavior were normal for age in the infant. Both patients were found to be compound heterozygotes for C914A (A305E) and G212A (R71H) mutations in ASPA. Like all other known ASPA mutations, this previously unknown G212A mutation appears to have low absolute enzyme activity. Nevertheless, it is associated in these patients with an extremely benign phenotype that is highly atypical of Canavan's disease. Biochemical and clinical data were evaluated using a generalized linear mixed model generated from 25 other subjects with Canavan's disease. There were statistically significant differences in brain chemistry and clinical evaluations, supporting a distinct variant of Canavan's disease. Future studies of ASPA enzyme structure and gene regulation in these subjects could lead to a better understanding of Canavan's pathophysiology and improvements in ASPA gene therapy.

The optical properties of ZnO hexagonal prisms grown from poly (vinylpyrrolidone)-assisted electrochemical assembly onto Si (111) substrate

ZnO hexagonal prisms have been grown from poly (vinylpyrrolidone)-assisted electrochemical assembly onto p-type Si (111) substrate. These ZnO prisms arrays are highly (0002) orientated. The (0001) end facets and {1010} side facets of the hexagonal prisms are well defined. The photoluminescence (PL) spectrum of these ZnO prisms shows an intense ultraviolet near band-gap emission with a full width at half maximum of 86 meV at room temperature. The low-temperature PL spectrum is split into well-resolved free and bound exciton emission lines. The temperature dependence of the exciton emission intensities shows a nonmonotonic decaying behavior, which can be explained by the existence of interfacial states.