Variability in research culture across busy catheterisation labs in the Asia-Pacific region.

Background: Information related to research culture in the busy catheterisation (cath) labs across the Asia-Pacific (APAC) region is sparse. Aims: The aims of this study were to examine the variability in research culture in busy cath labs in the APAC region and to propose a roadmap for hospitals to develop in-house research capabilities in conjunction with industry and academia. Methods: Data related to research practices in the APAC region were collected from busy cath labs (at least 250 angioplasty/year) and analysed. Results were shared with research experts to understand the challenges in institutional research and create a roadmap for hospitals to develop research capabilities. Results: A total of 220 respondents from 62 cath labs (88.6%) across 13 APAC countries participated in the survey. A wide variation was noted in research culture across APAC countries. Well-established infrastructure was reported in Australia, New Zealand, South Korea, Singapore, and Japan. Large multicentre trials were common in South Korea, while routine follow-ups were common in Japan. Linking medical records across hospitals/states was considered challenging. Research exposure and training were limited in the APAC region. The experts suggested a roadmap, including creating a conducive regulatory environment, forming synergistic goals, training programs for the professionals involved in research, and leveraging best practices, for improving the research culture in APAC. Conclusions: Clinical research in cardiology has grown significantly in the APAC region, with a huge research potential in China and India. Implementing measures to improve research training and involvement of the industry will boost the research culture in the APAC region.

Clinical use of optical coherence tomography during percutaneous coronary intervention and coronary procedures in Southeast Asia: a survey-based expert consensus summary.

Optical coherence tomography (OCT), an established intravascular imaging technique, enables rapid acquisition of high-resolution images during invasive coronary procedures to assist physician decision-making. OCT has utility in identifying plaque/lesion morphology (e.g., thrombus, degree of calcification, and presence of lipid) and vessel geometry (lesion length and vessel diameter) and in guiding stent optimisation through identification of malapposition and underexpansion. The use of OCT guidance during percutaneous coronary interventions (PCI) has demonstrated improved procedural and clinical outcomes in longitudinal registries, although randomised controlled trial data remain pending. Despite growing data and guideline endorsement to support OCT guidance during PCI, its use in different countries is not well established. This article is based on an advisory panel meeting that included experts from Southeast Asia (SEA) and is aimed at understanding the current clinical utility of intracoronary imaging and OCT, assessing the barriers and enablers of imaging and OCT adoption, and mapping a path for the future of intravascular imaging in SEA. This is the first Southeast Asian consensus that provides insights into the use of OCT from a clinician's point of view.

Bilateral adrenal cryptococcosis causing adrenal insufficiency in an immunocompetent patient.

ABSTRACT: Cryptococcosis usually occurs in immunocompromised patients and presents as meningitis and lung disease. Adrenal gland involvement may be observed, yet primary adrenal insufficiency by cryptococcal infection is infrequent. We present a case of a middle-aged immunocompetent man with primary adrenal insufficiency and bilateral adrenal lesions, splenomegaly, and miliary mottling in the lungs on imaging. No evidence of meningitis was witnessed. The clinico-radiological findings led toward the differential diagnosis of disseminated tuberculosis or fungal infection. Detection of cryptococcus organism was done on fine-needle aspiration cytology and biopsy on periodic acid-Schiff stain and Gomori`s methenamine silver stain. Thus, it is recommended to keep the possibility of cryptococcosis in mind while dealing with instances that have a tuberculosis-like clinico-radiological presentation. The detection of the causal organism on Fine needle aspiration (FNA)/biopsy examination may be useful in confirming the diagnosis and determining the appropriate medical treatment.

Post-hepatectomy venous thromboembolism: a systematic review with meta-analysis exploring the role of pharmacological thromboprophylaxis.

PURPOSE: Patients undergoing hepatectomy are at moderate-to-high risk of venous thromboembolism (VTE). This study critically examines the efficacy of combining pharmacological (PTP) and mechanical thromboprophylaxis (MTP) versus only MTP in reducing VTE events against the risk of hemorrhagic complications. METHODS: A systematic review of major reference databases was undertaken, and a meta-analysis was performed using common-effects model. Risk of bias assessment was performed using Newcastle-Ottawa scale. Trial sequential analysis (TSA) was used to assess the precision and conclusiveness of the results. RESULTS: 8 studies (n = 4238 patients) meeting inclusion criteria were included in the analysis. Use of PTP + MTP was found to be associated with significantly lower VTE rates compared to only MTP (2.5% vs 5.3%; pooled RR 0.50, p = 0.03, I2 = 46%) with minimal type I error. PTP + MTP was not associated with an increased risk of hemorrhagic complications (3.04% vs 1.9%; pooled RR 1.54, p = 0.11, I2 = 0%) and had no significant impact on post-operative length of stay (12.1 vs 10.8 days; pooled MD - 0.66, p = 0.98, I2 = 0%) and mortality (2.9% vs 3.7%; pooled RR 0.73, p = 0.33, I2 = 0%). CONCLUSION: Despite differences in the baseline patient characteristics, extent of hepatectomy, PTP regimens, and heterogeneity in the pooled analysis, the current study supports the use of PTP in post-hepatectomy patients (grade of recommendation: strong) as the combination of PTP + MTP is associated with a significantly lower incidence of VTE (level of evidence, moderate), without an increased risk of post-hepatectomy hemorrhage (level of evidence, low).

In-Silico Validation and Fabrication of Matrix Diffusion-Based Polymeric Transdermal Patches for Repurposing Gabapentin Hydrochloride in Neuropathic Pain.

BACKGROUND: Gabapentin (GBP) is an FDA-approved drug for the treatment of partial and secondary generalized seizures, apart from being used for diabetic neuropathic pain. GBP displays a highly intricate mechanism of action and its inhibitory response in elevated antagonism of NMDA (N-methyl-D-aspartate receptor) receptor and thus, can be repurposed for controlling neuropathic pain. OBJECTIVE: Therefore, in the present study, we have selected hBCATc (humanPyridoxal 5'-phosphate- dependent branched-chain aminotransferase cytosolic) gene that is highly expressed in silico validation through neuropathic stressed conditions. Thereafter, have analysed the GBP as its competitive inhibitor by in silico validation through homology modelling, molecular docking, also predicting its structural alerts and pharmacokinetic suitability through ADMET. However, and GBP was found to be a potential drug in controlling neuropathic pain, still, it has certain critical and pharmacokinetic limitations; therefore, the need for its targeted delivery was required, and the same was attained by designing a GBP loaded transdermal patch (GBP-TDP). METHODS: A suitable and equally efficacious GBP - TDP was developed by a solvent evaporation method using PVP and HPMC in the ratio of 2:1 as a polymer base for reservoir type of TDP. Also, PEG 400 was used as a plasticizer, and PVA (4%) was taken for backing membrane preparation, and then the optimized GBP-TDP was subjected for physical characterization, optimization and ex vivo release kinetics. RESULTS: The results showed desired specifications with uneven and flaky surface appearance giving an avenue for controlled release of the drugs with 92.34 ± 1.43% of drug release in 10 hours, further suggesting that GBP-TDP can be used as an effective tool against diabetic neuropathy pain. CONCLUSION: In this study, we have repurposed Gabapentin to treat diabetic neuropathy and validated the same by conducting a detailed in silico evaluation starting from homology Modelling of the target protein hBCATc, cross verified by the Ramachandran plot analysis with the most favoured region of 92.1% (encompassing 303 residues out of 386).

Classification of paediatric brain tumours by diffusion weighted imaging and machine learning.

To determine if apparent diffusion coefficients (ADC) can discriminate between posterior fossa brain tumours on a multicentre basis. A total of 124 paediatric patients with posterior fossa tumours (including 55 Medulloblastomas, 36 Pilocytic Astrocytomas and 26 Ependymomas) were scanned using diffusion weighted imaging across 12 different hospitals using a total of 18 different scanners. Apparent diffusion coefficient maps were produced and histogram data was extracted from tumour regions of interest. Total histograms and histogram metrics (mean, variance, skew, kurtosis and 10th, 20th and 50th quantiles) were used as data input for classifiers with accuracy determined by tenfold cross validation. Mean ADC values from the tumour regions of interest differed between tumour types, (ANOVA P < 0.001). A cut off value for mean ADC between Ependymomas and Medulloblastomas was found to be of 0.984 × 10-3 mm2 s-1 with sensitivity 80.8% and specificity 80.0%. Overall classification for the ADC histogram metrics were 85% using Naïve Bayes and 84% for Random Forest classifiers. The most commonly occurring posterior fossa paediatric brain tumours can be classified using Apparent Diffusion Coefficient histogram values to a high accuracy on a multicentre basis.

Termite's potential in solid waste management in Himachal Pradesh: A mini review.

One of the major reasons for the degradation of Earth's setting is inappropriate disposal of solid waste. Mountains of solid waste are increasing in every country making solid waste management a challenge almost everywhere on Earth. It is vital to look for such municipal solid waste management solutions that are financially sustainable, technically possible, socially and legally acceptable and environmentally friendly. Currently vermicomposting is the only biological solid waste treatment process that uses multicellular organisms to biodegrade organic wastes. A few species of insects are capable of digesting lignin and cellulose. Of these, termites are the most numerous and play a decisive role as scavengers. Microflora which inhabit the termites' gut contribute to their waste degrading potential. Termites act as major soil ecosystem managers and are able to breakdown and recycle organic matter and composite. Although studies in the potential of termites to increase soil fertility are well-accounted for in the literature, the potential of termites for solid waste management still needs to be explored. This mini review presents the state of information on the use of termite species in solid waste degradation focused on the potential application in the Himachal Pradesh region, India. This review highlights different termite species found in Himachal Pradesh and the challenges that are needed to be conquered. The study also aims at encouraging competent authorities/researchers to work towards the improvement of the present system by further exploring the use of termites in solid waste management through suggestions and recommendations.

Targeted Delivery for Neurodegenerative Disorders Using Gene Therapy Vectors: Gene Next Therapeutic Goals.

The technique of gene therapy, ever since its advent nearly fifty years ago, has been utilized by scientists as a potential treatment option for various disorders. This review discusses some of the major neurodegenerative diseases (NDDs) like Alzheimer's disease (AD), Parkinson's Disease (PD), Motor neuron diseases (MND), Spinal Muscular Atrophy (SMA), Huntington's Disease (HD), Multiple Sclerosis (MS), etc. and their underlying genetic mechanisms along with the role that gene therapy can play in combating them. The pathogenesis and the molecular mechanisms specifying the altered gene expression of each of these NDDs have also been discussed in elaboration. The use of gene therapy vectors can prove to be an effective tool in the field of curative modern medicine for the generations to come. Therefore, consistent efforts and progressive research towards its implementation can provide us with powerful treatment options for disease conditions that have so far been considered as incurable.

Quantitative MRI demonstrates abnormalities of the third ventricle subventricular zone in neurofibromatosis type-1 and sporadic paediatric optic pathway glioma.

BACKGROUND: The subventricular zone of the third ventricle (TVZ) is a germinal stem cell niche, identified as the possible location of optic pathway glioma (OPG) cell origin. Paediatric OPGs are predominantly diagnosed as low-grade astrocytomas, which are either sporadic or are associated with neurofibromatosis type-1 (NF1). These tumours often cause a significant impairment to visual acuity (VA). Infiltrative/invasive tumour activity is associated with increased apparent diffusion coefficient (ADC) and cerebral blood flow (CBF). This study aimed to determine whether TVZ imaging features differed between sporadic-OPG, NF1-OPG and controls, and whether the ADC and CBF profile at the germinal stem cell niche (the TVZ) correlated with the primary outcome of VA. METHODS: ADC and CBF MRI data were acquired from 30 paediatric OPG patients (median age 6 years; range 8 months-17 years), along with VA measurements, during clinical surveillance of their tumour. Values for mean ADC and maximum CBF were measured at the TVZ, and normalized to normal-appearing grey matter. These values were compared between the two OPG groups and the healthy control subjects, and multivariate linear regression was used to test the linear association between these values and patient's VA. RESULTS: In the TVZ, normalized mean ADC was higher in NF1-associated OPG patients (N = 15), compared to both sporadic OPG patients (N = 15; p = 0.010) and healthy controls (N = 14; p < 0.001). In the same region, normalized maximum CBF was higher in sporadic OPG patients compared to both NF1-OPG patients (p = 0.016) and healthy controls (p < 0.001). In sporadic OPG patients only, normalized mean ADC in the TVZ was significantly correlated with visual acuity (R2 = 0.41, p = 0.019). No significant correlations were found between TVZ CBF and ADC values and visual acuity in the NF1-associated OPG patients. CONCLUSION: Quantitative MRI detects TVZ abnormalities in both sporadic and NF1-OPG patients, and identifies TVZ features that differentiate the two. TVZ features may be useful MRI markers of interest in future predictive studies involving sporadic OPG.

Parents outlook on preventive dental modalities for their children in Udham Singh Nagar, India.

AIM: The aim is to evaluate the knowledge, attitude, and practices of parents toward preventive dental treatment modalities. METHODOLOGY: A convenient sample of parents was selected randomly from four schools of Udham Singh Nagar, India. The data were collected through questionnaire on dental preventive modalities. The questionnaire includes questions pertaining to knowledge and practices toward pit and fissure sealants, fluoride application, and dental visits. Questions pertaining attitude toward the same were asked after the motivational program. RESULTS: The majority of the parents were unaware that dental caries could be prevented by preventive treatment modalities. None of their children had undergone preventive procedures. Even after visiting dentist, 70% of parents were not informed about the preventive treatments by their respective dentists. Even after our motivational program, around one-third of the parents were reluctant to accept preventive procedures for their children. CONCLUSION: Parent's knowledge about the preventive dental procedures for their children was insufficient. Dentists are not encouraging parents about the benefits of preventive treatment modalities. Based on our findings, promotional efforts encouraged 64% of parents to embrace preventive procedures for their children. The present study emphasizes the need to educate parents and their children.

Cytotoxicity of Graphene Oxide (GO) and Graphene Oxide Conjugated Losartan Potassium (GO-LP) on Neuroblastoma (NB41A3) Cells.

Despite several advancements in the biomedical sciences, an efficient cancer therapy still remains a challenge. Nanomedicines have shown potential to overcome certain roadblocks faced in the existing treatment modalities. Losartan potassium (LP) which is a known vasodilator also exhibits anti fibrolytic and anti-metastatic properties altogether. Further, also being a potential angiotensin II type 1 receptor antagonist, it has been well explored for down regulating tumourogenic biomarkers like VEGF-A (Vascular endothelial growth factor A) and suppression of neovascularization, making it a suitable drug to target for cancer treatment. Besides this, it too reflected the stimulation of pro apoptotic signaling pathways. But due to its lower bioavailability and extensive hepatic metabolism its therapeutic index reduces down. Thus, the present study is focused on designing a nano-delivery system using graphene oxide (GO) as a nano-vehicle and conjugated the LP with it. Then, the successful synthesis of GO and GO-LP nano conjugates were characterized by high-resolution transmission electron microscopy, X-ray diffraction, FTIR and UV visible spectroscopy, confirming the formation of nanosheets. The qualitative morphological evaluation of NB41A3 neuroblastoma cell line treated with bare GO, LP and GO-LP using microscopy and DAPI staining revealed the inhibitory action of GO-LP nano conjugate on cell proliferation. Additionally, the cytotoxicity was also estimated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Nitric oxide (NO) and Lactate dehydrogenase (LDH) assays. The results show that GO-LP significantly suppresses the cell viability in comparison to control and bare GO suggesting that the designed system may express its potential to be used with existing chemo drugs for the treatment of neural cancers.

Selection of suitable reference genes for normalization of quantitative RT-PCR (RT-qPCR) expression data across twelve tissues of riverine buffaloes (Bubalus bubalis).

Selection of reference genes has become an integral step in any real time quantitative PCR (RT-qPCR) based expression studies. The importance of this study stems from the fact that riverine buffaloes are major dairy species of Indian sub-continent and the information generated here will be of great interest to the investigators engaged in functional genomic studies of this important livestock species. In this study, an effort was made to evaluate a panel of 10 candidate reference genes (glyceraldehyde 3-phosphate dehydrogenase (GAPDH), beta- actin (ACTB), ubiquitously expressed transcript (UXT), ribosomal protein S15 (RPS15), ribosomal protein L-4 (RPL4), ribosomal protein S9 (RPS9), ribosomal protein S23 (RPS23), hydroxymethylbilane synthase (HMBS), ß2 Microglobulin (ß2M) and eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) across 12 tissues (mammary gland, kidney, spleen, liver, heart, intestine, ovary, lung, muscle, brain, subcutaneous fat and testis) of riverine buffaloes. In addition to overall analysis, tissue wise evaluation of expression stability of individual RG was also performed. Three different algorithms provided in geNorm, NormFinder and BestKeeper softwares were used to evaluate the stability of 10 potential reference genes from different functional classes. The M-value given by geNorm ranged from 0.9797 (RPS9 and UXT) to 1.7362 (RPS15). From the most stable to the least stable, genes were ranked as: UXT/RPS9> RPL4> RPS23> EEF1A1> ACTB> HMBS> GAPDH> B2M> RPS15. While NormFinder analysis ranked the genes as: UXT> RPS23> RPL4> RPS9> EEF1A1> HMBS> ACTB> ß2M> GAPDH> RPS15. Based on the crossing point SD value and range of fold change expression, BestKeeper analysis ranked the genes as: RPS9> RPS23/UXT> RPL4> GAPDH> EEF1A1> ACTB> HMBS> ß2M> RPS15. Overall the study has identified RPS23, RPS9, RPL4 and UXT genes to be the most stable and appropriate RGs that could be utilized for normalization of transcriptional data in various tissues of buffaloes. This manuscript thus provide useful information on panel of reference genes that could be helpful for researchers conducting functional genomic studies in riverine buffaloes.

Delineation of the visual pathway in paediatric optic pathway glioma patients using probabilistic tractography, and correlations with visual acuity.

Background: Radiological biomarkers which correlate with visual function are needed to improve the clinical management of optic pathway glioma (OPG) patients. Currently, these are not available using conventional magnetic resonance imaging (MRI) sequences. The aim of this study was to determine whether diffusion MRI could be used to delineate the entire optic pathway in OPG patients, and provide imaging biomarkers within this pathway which correlate with a patient's visual acuity (VA). Methods: Multi-shell diffusion MRI data were acquired in a cohort of paediatric OPG patients, along with VA measurements in each eye. Diffusion MRI data were processed using constrained spherical deconvolution and probabilistic fibre tractography, to delineate the white matter bundles forming the optic pathway in each patient. Median fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured in the optic nerves, tracts, and radiations, and correlated against each patient's VA. Results: In the optic nerves, median FA significantly correlated with VA (R2adj = 0.31, p = 0.0082), with lower FA associated with poorer vision. In the optic radiations, both lower FA and higher ADC were significantly associated with poorer vision (R2adj = 0.52, p = 0.00075 and R2adj = 0.50, p = 0.0012 respectively). No significant correlations between VA and either FA or ADC were found in the optic tracts. Conclusions: Multi-shell diffusion MRI provides in vivo delineation of the optic pathway in OPG patients, despite the presence of tumour invasion. This technique provides imaging biomarkers which are sensitive to microstructural damage to the underlying white matter in this pathway, which is not always visible on conventional MRI.

Bio Pharmaceutics Classification System (BCS) Class IV Drug Nanoparticles: Quantum Leap to Improve Their Therapeutic Index.

Purpose: Biopharmaceutics classification system (BCS) class IV compounds, exhibits least oral bioavailability, low solubility and intestinal permeability among all pharmaceutical classes of drugs. Thus, these drugs need more compatible and efficient delivery system. Since, their solubility in various medium, remains a limitation so, polymeric nano coacervates based drug loading with modified approach for them may prove to be a solution ahead. Therefore, in present study Chitosan is opted for encapsulating the BCS class IV drug (Hydrochlorothiazide) to attain better stability, enhanced permeability and lower toxicity. Methods: For this study, Hydrochlorothiazide (HCTZ) was opted for formulating chitosan based nano-coacervate system. Results: Optimized HCTZ nanocoacervates exhibited the average particle size of 91.39 ± 0.75 nm with Poly-dispersity index score of 0.159 ± 0.01, indicating homogeneity of colloidal solution. Zeta potential and encapsulation efficiency of HCTZ nanocoacervates were recorded as -18.9 ± 0.8 mV and 76.69 ± 0.82 % respectively. Further, from TEM and SEM evaluation the average particle size for the same were found in conformity (35-50 nm), with almost spherical morphology. Also, the EDX (Electron Dispersive X-ray) spectrometry and FT - IR analysis of optimized formulation indicated the balanced chemical composition and interaction between the polymeric molecules. The HCTZ nano coacervates showed the linear diffusion profile through the dialysis membrane. Conclusion: We can conclude from the present study that the optimized HCTZ nano coacervates may prove to be a suitable potential option for effective delivery of BCS class IV drugs.

Assessment of hepatotoxicity of first-line anti-tuberculosis drugs on Wistar rats.

Adverse drug reactions are inevitable risk factors associated with use of modern medicines. First-line anti-tuberculosis drugs contribute to diverse pathological complications, and hepatotoxicity is one of them. This study investigated the effects of anti-TB drugs in combination (rifampicin [RIF] + isoniazid [INH] + pyrazinamide [PZA]) on Wistar rats. Rats were grouped as control group (saline), toxicant group that was given (30.85 mg/kg b.wt., INH + 61.7 mg/kg b.wt., RIF + 132.65 mg/kg b.wt. PZA in dosage extrapolated from dose that is used in human). Different anti-oxidant enzymes were measured in the liver along with histopathology, hematology, genotoxic effect on bone marrow chromosomes, and DNA fragmentation. In addition, gene and protein expression of CYP2E1, NR1I2, NAT, and CYP7A1 was measured by qPCR and western blot. After administration of anti-TB drugs to Wistar rats for 28 days, there was an increase in thiobarbituric acid reactive substances and a decrease in anti-oxidant enzymes. Marked changes in histopathology, hematology, DNA fragmentation, chromosomes, and in gene expression were observed. Results of the study proved increased hepatotoxicity due to combinational treatment of anti-TB drugs and also that CYP2E1, NR1I2, NAT, and CYP7A1 genes play a vital role in anti-TB drug-induced hepatotoxicity.

Molecular Characterization of Pro-Inflammatory Cytokines Interleukin-1ß and Interleukin-8 in Asian Elephant (Elephas maximus).

Interleukin (IL)-1ß and IL-8 are pro-inflammatory cytokines produced primarily by monocytes and macrophages in response to a variety of microbial and nonmicrobial agents. As yet, no molecular data have been reported for IL-1ß and IL-8 of the Asian elephant. In the present study, we have cloned and sequenced the cDNA encoding IL-1ß and IL-8 of the Asian elephant. The open reading frame (ORF) of Asian elephant IL-1ß is 789 bp in length, encoded a propeptide of 263 amino acid polypeptide. The predicted protein revealed the presence of IL-1 family signature motif and an ICE cut site. Whereas, IL-8 contained 321 bp of open reading frame. Interestingly, the predicted protein sequence of 106 aa, contains an ELR motif immediately upstream of the CQC residues, common in all vertebrate IL-8 molecules. Identity levels of the nucleic acid and deduced amino acid sequences of Asian elephant IL-1ß ranged from 68.48 (Squirrel monkey) to 98.57% (African elephant), and 57.78 (Sheep) to 98.47% (African elephant), respectively, whereas that of IL-8 ranged from 72.9% (Human) to 87.8% (African elephant), and 63.2 (human, gorilla, chimpanzee) to 74.5% (African elephant, buffalo), respectively. The phylogenetic analysis based on deduced amino acid sequenced showed that the Asian elephant IL-1ß and IL-8 were most closely related to African elephant. Molecular characterization of these two cytokines, IL-1ß and IL-8, in Asian elephant provides fundamental information necessary to progress the study of functional immune responses in this animal and gives the potential to use them to manipulate the immune response as recombinant proteins.

Challenges for the functional diffusion map in pediatric brain tumors.

BACKGROUND: The functional diffusion map (fDM) has been suggested as a tool for early detection of tumor treatment efficacy. We aim to study 3 factors that could act as potential confounders in the fDM: areas of necrosis, tumor grade, and change in tumor size. METHODS: Thirty-four pediatric patients with brain tumors were enrolled in a retrospective study, approved by the local ethics committee, to examine the fDM. Tumors were selected to encompass a range of types and grades. A qualitative analysis was carried out to compare how fDM findings may be affected by each of the 3 confounders by comparing fDM findings to clinical image reports. RESULTS: Results show that the fDM in areas of necrosis do not discriminate between treatment response and tumor progression. Furthermore, tumor grade alters the behavior of the fDM: a decrease in apparent diffusion coefficient (ADC) is a sign of tumor progression in high-grade tumors and treatment response in low-grade tumors. Our results also suggest using only tumor area overlap between the 2 time points analyzed for the fDM in tumors of varying size. CONCLUSIONS: Interpretation of fDM results needs to take into account the underlying biology of both tumor and healthy tissue. Careful interpretation of the results is required with due consideration to areas of necrosis, tumor grade, and change in tumor size.

A two-stage model for in vivo assessment of brain tumor perfusion and abnormal vascular structure using arterial spin labeling.

The ability to assess brain tumor perfusion and abnormalities in the vascular structure in vivo could provide significant benefits in terms of lesion diagnosis and assessment of treatment response. Arterial spin labeling (ASL) has emerged as an increasingly viable methodology for non-invasive assessment of perfusion. Although kinetic models have been developed to describe perfusion in healthy tissue, the dynamic behaviour of the ASL signal in the brain tumor environment has not been extensively studied. We show here that dynamic ASL data acquired in brain tumors displays an increased level of 'biphasic' behaviour, compared to that seen in healthy tissue. A new two-stage model is presented which more accurately describes this behaviour, and provides measurements of perfusion, pre-capillary blood volume fraction and transit time, and capillary bolus arrival time. These biomarkers offer a novel contrast in the tumor and surrounding tissue, and provide a means for measuring tumor perfusion and vascular structural abnormalities in a fully non-invasive manner.