Parametric exploration of the liver by magnetic resonance methods

MRI, as a completely noninvasive technique, can provide quantitative assessment of perfusion, diffusion, viscoelasticity and metabolism, yielding diverse information about liver function. Furthermore, pathological accumulations of iron and lipids can be quantified. Perfusion MRI with various contrast agents is commonly used for the detection and characterization of focal liver disease and the quantification of blood flow parameters. An extended new application is the evaluation of the therapeutic effect of antiangiogenic drugs on liver tumours. Novel, but already widespread, is a histologically validated relaxometry method using five gradient echo sequences for quantifying liver iron content elevation, a measure of inflammation, liver disease and cancer. Because of the high perfusion fraction in the liver, the apparent diffusion coefficients strongly depend on the gradient factors used in diffusion-weighted MRI. While complicating analysis, this offers the opportunity to study perfusion without contrast injection. Another novel method, MR elastography, has already been established as the only technique able to stage fibrosis or diagnose mild disease. Liver fat content is accurately determined with multivoxel MR spectroscopy (MRS) or by faster MRI methods that are, despite their widespread use, prone to systematic error. Focal liver disease characterisation will be of great benefit once multivoxel methods with fat suppression are implemented in proton MRS, in particular on high-field MR systems providing gains in signal-to-noise ratio and spectral resolution

Post-mortem volatiles of vertebrate tissue

Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted

Near-infrared laser spectroscopy of TiS: The b1II-X3Δ transition

Laser-induced fluorescence spectrum of TiS in the 769-863 nm region has been recorded and analyzed. The TiS molecule was produced using the technique of laser vaporization/reaction with supersonic cooling. Twenty-one weak subbands have been assigned as being due to b 1II-X 3, B 3II 0-X 3Δ 1, and C 3Δ-X 3Δ transitions. Strong evidence shows that the b 1II state is responsible for perturbing the v = 0, 1, and 2 levels of the C 3Δ 1 subband. The molecular constants of the b 1II state have been determined as follows: T e = 10 589.47 cm -1, ω e = 542.14 cm -1, ω ex e = 3.16 cm -1, B e = 0.19568 cm -1, and α e = 0.00085 cm -1. The spin-orbit interaction between the b 1II (v = 2 and 3) and C 3Δ (v = 1 and 2) levels is discussed in terms of configuration interaction occurring between the b 1II from the 11σ 1 5π 1 configuration and the 1II from the 5π 1 1δ 1 configuration, and the C 3Δ state from 12σ 1 1δ 1 configuration, © 2000 Academic Press.link_to_subscribed_fulltex

Implications of abdominal adipose tissue distribution on nonalcoholic fatty liver disease and metabolic syndrome : a Chinese general population study

202407 bcchVersion of RecordOthersHealth and Health Services Research Fund sponsored by the Government of Hong Kong SAR (Reference number 07080081)PublishedC

Blood oxygen level-dependent functional magnetic resonance imaging in preoperative brain mapping and making surgical decisions

血氧水平依賴腦功能磁共振成像對於 術前研究腦功能區活動的效用及對手術方式的影響 麥嘉豐、張粼達、馮仕庭、楊家威、陳達明、朱献倫、潘偉生 目的：評估血氧水平依賴腦功能磁共振成像對於術前研究感應運動腦皮質區及語言區活動的效用， 以及對手術方式採用決定的影響。 方法：14名患有腫瘤或血管畸形的病人接受功能磁共振成像（通過運動、感覺及語言任務）及1.5T 的結構磁共振成像。並探討功能磁共振成像的結果與術中及臨床結果的相關性。最終共有7名病人接 受全身麻醉的顱骨切開術、3人接受喚醒麻醉的顱骨切開術及術中成像、2人接受放射外科手術、2人 未有接受手術。 結果：使用功能磁共振成像的信號強度辨認語言功能區的技術性成功率為100%，但閱讀中文方面則 只有83%。腦功能磁共振成像的準確度的驗證取决於術中皮層電刺激或皮層體感誘發電位逆轉。有 75%病人因功能磁共振成像的結果而影響其做手術方式的決定，其中2人採用更進取的方法，另2人 因病灶距離語言功能區只有不足2 cm，所以採用較安全的方法。另5人由於距離大（超過2 cm）或語 言區在對側位置，遂進行傳統的顱骨切開術。另1人的瓦達測試（Wada test）與功能磁共振成像在語 言側化方面的結果矛盾，後進行術中皮層電刺激測試確定功能磁共振成像正確預測語言區優勢的一 邊。 結論：血氧水平依賴腦功能磁共振成像有較高技術成功率，在術前辨認語言功能區方面相當準確。 此技術對於術前評估起了關鍵作用，可推薦作大部分腦腫瘤切開術用作術前評估。Objective: To evaluate the efficacy of blood oxygen level–dependent functional magnetic resonance imaging in the preoperative mapping of sensorimotor cortices and language areas, and its impact on surgical decisions. Methods: Fourteen patients with tumours or vascular malformations underwent functional magnetic resonance imaging (in the course of motor, sensory, and language tasks) and had structural magnetic resonance imaging scans in a 1.5T scanner. The functional magnetic resonance imaging findings were then correlated with their operative and clinical outcomes. Seven patients had a craniotomy with general anaesthesia, three had awake craniotomy with intraoperative mapping, two had radiosurgery, and two had no surgery. Results: The technical success rate of functional magnetic resonance imaging signal activation in identifying eloquent cortices was 100% for all tasks except Chinese reading, for which the success rate was 83%. Functional magnetic resonance imaging mapping accuracy was determined by correlation with intraoperative cortical stimulation or somatosensory-evoked potentials phase reversal. Surgical decision making was influenced by functional magnetic resonance imaging in 75% of the patients, using a more aggressive approach in two patients and a safer approach in two others (due to lesion proximity of 2 cm) or contralateral location of the language centre. In one patient, there were conflicting results between Wada test and functional magnetic resonance imaging with respect to speech lateralisation; intraoperative cortical stimulation found that functional magnetic resonance imaging correctly predicted the side of speech dominance. Conclusion: Blood oxygen level–dependent functional magnetic resonance imaging had a high technical success rate and was very accurate in mapping eloquent cortical areas preoperatively. Its role in preoperative surgical assessment is pivotal, and is recommended for most, if not all, resective brain surgery.link_to_subscribed_fulltex

The relationship between pancreas steatosis and the risk of metabolic syndrome and insulin resistance in Chinese adolescents with concurrent obesity and non-alcoholic fatty liver disease

202407_adaVersion of RecordOthersDirect Grant for Research, Grant/Award Number: 2014.1.065; Health and Medical Research Fund, Food and Health Bureau, Grant/Award Number: 11122981PublishedC

Vertebral bone mineral density, marrow perfusion, and fat content in healthy men and men with osteoporosis: Dynamic contrast-enhanced MR imaging and MR spectroscopy

PURPOSE: To prospectively use hydrogen 1 ( 1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes. RESULTS: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 ± 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 ± 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 ± 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% ± 7.8) (P = .002) or osteopenia (mean fat content, 55.68% ± 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% ± 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/ sec ± 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec ± 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec ± 0.7) (P < .001). CONCLUSION: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density. © RSNA, 2005.link_to_subscribed_fulltex

Does acupuncture therapy alter activation of neural pathway for pain perception in irritable bowel syndrome?: A comparative study of true and sham acupuncture using functional magnetic resonance imaging

Background/Aims: Patients with irritable bowel syndrome (IBS) are characterized by abnormal central processing with altered brain activation in response to visceral nociceptive signals. The effect of electroacupuncture (EA) on IBS patients is unclear. The study is set to study the effect of EA on brain activation during noxious rectal distension in IBS patients using a randomized sham-controlled model. Methods: Thirty IBS-diarrhea patients were randomized to true electroacupuncture or sham acupuncture. Functional MRI was performed to evaluate cerebral activation at the following time points: (1) baseline when there was rectal distension only, (2) rectal distension during application of EA, (3) rectal distension after cessation of EA and (4) EA alone with no rectal distension. Group comparison was made under each condition using SPM5 program. Results: Rectal distension induced significant activation of the anterior cingulated cortex, prefrontal cortex, thalamus, temporal regions and cerebellum at baseline. During and immediately after EA, increased cerebral activation from baseline was observed in the anterior cingulated cortex, bilateral prefrontal cortex, thalamus, temporal regions and right insula in both groups. However, true electroacupuncture led to significantly higher activation at right insula, as well as pulvinar and medial nucleus of the thalamus when compared to sham acupuncture. Conclusions: We postulate that acupuncture might have the potential effect of pain modulation in IBS by 2 actions: (1) modulation of serotonin pathway at insula and (2) modulation of mood and affection in higher cortical center via ascending pathway at the pulvinar and medial nucleus of the thalamus. © 2012 The Korean Society of Neurogastroenterology and Motility.link_to_subscribed_fulltex

Does acupuncture therapy alter activation of neural pathway for pain perception in irritable bowel syndrome? : a comparative study of true and sham acupuncture using functional magnetic resonance imaging

202012 bcrcVersion of RecordPublishe