Noncontrast MRI for Hepatocellular Carcinoma Detection: A Systematic Review and Meta-analysis - A Potential Surveillance Tool?

BACKGROUND AND AIMS: This meta-analysis investigates the diagnostic performance of non-contrast magnetic resonance imaging (MRI) for the detection of hepatocellular carcinoma (HCC). METHODS: A systematic review was performed to May 2020 for studies which examined the diagnostic performance of non-contrast MRI (multi-sequence or diffusion-weighted imaging (DWI)- alone) for HCC detection in high risk patients. The primary outcome was accuracy for the detection of HCC. Random effects models were used to pool outcomes for sensitivity, specificity, positive likelihood ratio (LR) and negative LR. Subgroup analyses for cirrhosis and size of the lesion were performed. RESULTS: Twenty-two studies were included involving 1685 patients for per-patient analysis and 2128 lesions for per-lesion analysis. Multi-sequence non-contrast MRI (NC-MRI) using T2+DWI±T1 sequences had a pooled per-patient sensitivity of 86.8% (95%CI:83.9-89.4%), specificity of 90.3% (95%CI:87.3-92.7%), and negative LR of 0.17 (95%CI:0.14-0.20). DWI-only MRI (DW-MRI) had a pooled sensitivity of 79.2% (95%CI:71.8-85.4%), specificity of 96.5% (95%CI:94.3-98.1%) and negative LR of 0.24 (95%CI:1.62-0.34). In patients with cirrhosis, NC-MRI had a pooled per-patient sensitivity of 87.3% (95%CI:82.7-91.0%) and specificity of 81.6% (95%CI:75.3-86.8%), whilst DWI-MRI had a pooled sensitivity of 71.4% (95%CI:60.5-80.8%) and specificity of 97.1% (95%CI:91.9-99.4%). For lesions <2 cm, the pooled per-lesion sensitivity was 77.1% (95%CI:73.8-80.2%). For lesions >2 cm, pooled per-lesion sensitivity was 88.5% (95%CI:85.0-91.5%). CONCLUSION: Non-contrast MRI has a moderate negative LR and high specificity with acceptable sensitivity for the detection of HCC, even in patients with cirrhosis and with lesions <2 cm. Prospective trials to validate if non-contrast MRI can be used for HCC surveillance is warranted.

Artefact on CT brain images caused by the presence of air bubbles in the cooling oil of the X-ray tube.

INTRODUCTION: We report a series of patients who had computed tomography (CT) of their brains which showed an uncommon artefact caused by excess air bubbles in the cooling oil around the X-ray tube. METHODS: In November and December 2015, it was recognised that artefacts appearing on CT brain images acquired at our department were caused by a scanner fault. The test images were reviewed and the service engineer for the CT scanner was questioned about the artefact cause. A retrospective audit was then performed of images acquired on the CT scanner from December 2015 back to the date that the CT scanner was last serviced in September 2015 to identify any other scans affected by the artefact. RESULTS: Seven patients were identified whose CT brain scans showed the artefact. The artefact manifested in the form of an ill-defined low density area in varying locations. The artefact also appeared on CT phantom test images. It was discovered to be caused by the presence of excess air bubbles within the cooling oil of the X-ray tube. The fault was then rectified. CONCLUSIONS: The artefact described may not be easily recognised and could lead to misinterpretation and unnecessary investigation. We aim to promote awareness of this artefact and to reinforce the importance of frequent quality control testing of CT systems.

Alopecia and its association with coronary heart disease and cardiovascular risk factors: a meta-analysis.

BACKGROUND: Alopecia has been associated with an increased risk of coronary heart disease as well as the following risk factors for cardiovascular disease: hyperinsulinaemia, insulin resistance, metabolic syndrome, dyslipidaemia, and hypertension. We performed a meta-analysis to quantitatively determine the level of risk of coronary heart disease and risk factors in individuals with alopecia. METHODS: A systematic literature search was conducted using several databases. We calculated pooled odds ratios and 95% confidence intervals using a random effects model. RESULTS: In total, 31 studies comprising 29,254 participants with alopecia were eligible for the meta-analysis and showed that alopecia is associated with an increased risk of coronary heart disease (OR 1.22, 95% CI: 1.07-1.39), hyperinsulinaemia (OR 1.97, 95% CI: 1.20-3.21), insulin resistance (OR 4.88, 95% CI: 2.05-11.64), and metabolic syndrome (OR 4.49, 95% CI: 2.36-8.53). Individuals with alopecia were also shown to be more likely compared to those without alopecia to have higher serum cholesterol levels (OR 1.60, 95% CI: 1.17-2.21), higher serum triglyceride levels (OR 2.07, 95% CI: 1.32-3.25), higher systolic blood pressures (OR 1.73, 95% CI: 1.29-2.33), and higher diastolic blood pressures (OR 1.59, 95% CI: 1.16-2.18). CONCLUSIONS: Alopecia is associated with an increased risk of coronary heart disease, and there appears to be a dose-response relationship with degree of baldness whereby the greater the severity of alopecia, the greater the risk of coronary heart disease. Alopecia is also associated with an increased risk of hypertension, hyperinsulinaemia, insulin resistance, metabolic syndrome, and having elevated serum total cholesterol and triglyceride levels.