Magnetization Transfer Contrast - Is it Sensitive Enough to Differentiate Demyelination from Axonal Loss?

Background and Objective: Magnetization transfer contrast imaging (MTC) exploits the principle of exchange of energy between the bound and free protons and was shown to be pathologically informative. There is, however, controversy as to whether it correlates with axonal loss (AL), demyelination (DM), or both. This study addresses the pathophysiological process that underlies the white matter injury using the metric derivative of MTC, magnetization transfer ratio (MTR), and defines the role of MTR in identifying the different stages of inflammation, that is, edema, DM, and AL, using optic nerve as the model. Materials and Methods: One hundred and forty-two patients with a single, unilateral episode of optic neuritis (ON) were included in the study. Patients were divided into three groups - those with AL, those with DM, and those who were clinically optic neurites but without any electrophysiological changes suggestive of either AL or DM. MTR and electrophysiological studies were performed in the post-acute stage of ON and the results were compared to those obtained from the unaffected optic nerve. Results: MTR was significantly reduced in the optic nerves of both DM and AL groups when compared to that in normal optic nerves (P < 0.001). The difference in MTR between the AL and DM groups did not reach statistical significance. Patient group with acute ON did not show any change in the MTR values compared to the normal controls. Conclusions: MTR is a sensitive technique to identify neuronal injury, whether it is DM or AL. It, however, cannot differentiate these two pathological processes. MTR is not sensitive to identify acute ON.

Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio use in detecting bowel ischaemia in adhesional small bowel obstruction.

BACKGROUND: Bowel ischaemia significantly increases morbidity and mortality from adhesional small bowel obstruction. Current biomarkers and clinical parameters have poor predictive value for ischaemia. Our study investigated whether neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) could be used to predict bowel ischaemia in adhesional small bowel obstruction. METHODS: This single-centre retrospective study collected clinical, biochemical and radiological data from patients with adhesional small bowel obstruction between 2017 and 2020 who underwent operative management. The presence or absence of bowel ischaemia/infarction was used to distinguish two populations. Biochemical markers on admission and immediately prior to operation were collected to give platelet-lymphocyte ratio (PLR0 and PLRPRE-OP , respectively) and neutrophil-lymphocyte ratio (NLR0 and NLRPRE-OP , respectively). SAS 9.4 (SAS Institute Inc., Cary, NC) software was used for data analysis with Mann-Whitney U testing for continuous variables and Pearson Chi-square test for categorical variables. Sensitivity and specificity for PLR and NLR were calculated by means of receiver operating characteristic (ROC) curve analysis. RESULTS: Twenty-seven patients had intra-operative bowel ischaemia whilst the remaining 73 had no evidence of bowel ischaemia. Both median PLRPRE-OP and NLRPRE-OP were significantly higher in patients with bowel ischaemia compared to those without (PLRPRE-OP 272 [IQR 224-433] and 231 [IQR 146-295] respectively, P = 0.027; NLRPRE-OP 12.5 [IQR 8.6-21.3] v. 5.5 [IQR 3.5-10.2] respectively, P ≤ 0.001). Area under the receiver operator characteristic curve (AUC) was 0.762 for NLRPRE-OP , with a sensitivity of 85.1% and specificity of 63% for NLR 7.4. CONCLUSION: Raised NLR is predictive of bowel ischaemia in patients with adhesional small bowel obstruction.

Differentiation of Primary Central Nervous System Lymphoma and High-Grade Glioma with Dynamic Susceptibility Contrast-Derived Metrics: Pilot Study.

OBJECTIVE: Preoperative differentiation of lymphoma from other aggressive intracranial neoplasms is important as the surgical and adjuvant therapy may be fundamentally different between the 2 types of tumors. The purpose of this study was to assess the ability of the dynamic susceptibility contrast-derived metrics, percentage signal recovery (PSR) ratio, and relative cerebral blood volume (rCBV) to distinguish between primary central nervous system lymphoma (PCNSL) and high-grade glioma (HGG). METHODS: Twenty-six patients (15 with HGG and 11 with PCNSL) with histologically confirmed diagnoses were retrospectively analyzed. Mean PSR and rCBV were calculated from dynamic susceptibility contrast imaging. The 2 groups were compared using an independent samples t-test. Receiver operating characteristic analyses were performed to determine the area under the curve and identify threshold values to differentiate PCNSL from GBM. RESULTS: Both rCBV and PSR values were significantly different, at both the group level and subject level, between the PCNSL and HGG patients. The mean rCBV was significantly lower in PCNSL (1.38 ± 0.64) compared with HGG (5.19 ± 2.21, df = 11.24, P < 0.001). The mean PSR ratio was significantly higher in PCNSL (1.04 ± 0.11) compared with HGG (0.72 ± 0.16, df = 17.23, P < 0.001). An rCBV threshold value of 2.67 provided a 100% sensitivity and 100% specificity (area under the curve 1.0) for differentiating PCNSL from HGG. A PSR ratio threshold value of 0.9 was 100% sensitive and 90.91% specific for differentiating PCNSL from HGG. CONCLUSIONS: The findings of our study show that rCBV and PSR ratio are different in HGG and PCNSL at both the group level and subject level. Incorporation of perfusion in routine magnetic resonance imaging of contrast-enhancing lesions can have a significant impact on patient management.

Black blood imaging of intracranial vessel walls.

Traditional vascular imaging focuses on non-invasive cross-sectional imaging to assess luminal morphology; however, the vessel wall itself may be specifically involved in many diseases. Newer pulse sequences, and particularly black blood MRI of intracranial vessels, have brought a paradigm shift in understanding the pathophysiology of many vasculopathies. Black blood MRI of intracranial vessel walls can help in a range of pathologies with differing pathophysiology, including intracranial atherosclerosis, aneurysms, vasculitis and vasculopathy, moyamoya disease, dissection and vertebrobasilar hypoplasia. This review highlights how vessel wall imaging can contribute to the clinical diagnosis and management of patients with intracranial vascular pathology.

Hibernoma Demonstrated on 68Ga-DOTATATE PET/CT.

A 60-year-old woman with recently diagnosed neuroendocrine tumors underwent staging Ga-DOTATATE PET/CT, which revealed focal uptake within the right sacral ala. Histopathology of the right sacral ala confirmed hibernoma. This case illustrates that hibernoma can be a cause of false-positive intraosseous accumulation of Ga-DOTATATE.

A prospective study of nomogram-based adaptation of prostate radiotherapy target volumes.

BACKGROUND: A prospective clinical trial was conducted to evaluate the feasibility of a novel approach to the treatment of patients with high risk prostate cancer (HRPC) through the use of a nomogram to tailor radiotherapy target volumes. METHODS: Twenty seven subjects with HRPC were treated with a mildly hypofractionated radiotherapy regimen using image-guided IMRT technique between Jun/2013-Jan/2015. A set of validated prognostic factors were inputted into the Memorial-Sloan-Kettering Cancer Center (MSKCC) prostate cancer nomogram to estimate risk of loco-regional spread (LRS). The nomogram risk estimates for extra-capsular extension (ECE), seminal vesicles involvement (SVI), and pelvic lymph nodes involvement (LNI) were used to adapt radiotherapy treatment volumes based on a risk threshold of ≥15 % in all cases. A planning guide was used to delineate target volumes and organs at risk (OAR). Up to three dose levels were administered over 28 fractions; 70Gy for gross disease in the prostate +/- seminal vesicles (2.5Gy/fraction), 61.6Gy for subclinical peri-prostatic disease (2.2Gy/fraction) and 50.4Gy to pelvic nodes (1.8Gy/fraction). Data regarding protocol adherence, nomogram use, radiotherapy dose distribution, and acute toxicity were collected. RESULTS: Nomogram use 100 % of patients were treated for ECE, 88.9 % for SVI, and 70.4 % for LNI. The three areas at risk of LRS were appropriately treated according to the study protocol in 98.8 % cases. The MSKCC nomogram estimates for LRS differed significantly between the time of recruitment and analysis. Contouring protocol compliance Compliance with the trial contouring protocol for up to seven target volumes was 93.0 % (159/171). Compliance with protocol for small bowel contouring was poor (59.3 %). Dose constraints compliance Compliance with dose constraints for target volumes was 97.4 % (191/196). Compliance with dose constraints for OAR was 88.2 % (285/323). Acute toxicity There were no grade 3 acute toxicities observed. 20/27 (74.1 %) and 6/27 (22.2 %) patients experienced a grade 2 genitourinary and gastrointestinal toxicity respectively. CONCLUSIONS: We have demonstrated the feasibility of this novel risk-adapted radiation treatment protocol for HRPC. This study has identified key learning points regarding this approach, including the importance of standardization and updating of risk quantification tools, and the utility of an observer to verify their correct use. TRIAL REGISTRATION: ClincialTrials.gov identifier NCT01418040 . Hunter New England Human Research Ethics Committee (HNEHREC) reference number 12/08/15/4.02.

Patterns of emotional expression and responses to health and illness in women with functional voice disorders (MTVD) and a comparison group.

OBJECTIVES: To determine whether emotional expression, alexithymia, illness behavior, and coping strategies differed between women with muscle tension voice disorder (MTVD) and those without voice disorder and between women with and without mucosal pathology of the vocal folds, and to explore possible links between psychosocial constructs and clinical features in women with MTVD. STUDY DESIGN AND METHOD: A within-subjects design matched 20 women with MTVD and 20 women without voice disorder on validated self-report measures of the psychosocial constructs. The effect of mucosal pathology was assessed using between-groups analyses. Correlations assessed relationships between psychosocial constructs and clinical features. RESULTS: Comparisons between women with MTVD and those without voice disorder showed an elevated sense of illness identity and greater belief in the presence of somatic illness in women with MTVD. There was a trend toward women with MTVD showing lower levels of emotional awareness. Women without vocal fold pathology reported lower levels of emotional awareness than those with pathology, whereas women with pathology reported greater use of a mixed pattern of adaptive and maladaptive coping strategies than those with no pathology. Low vocal load was associated with higher scores on alexithymia, higher numbers of vocal symptoms were associated with the use of adaptive coping, and greater impact of symptoms was associated with higher levels of emotional awareness and greater belief in the presence of somatic illness. CONCLUSIONS: These findings encourage further investigation of relationships between emotional awareness, illness behavior, and coping in women with functional voice disorders.