RESUMO
BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is becoming the most common cause of cirrhosis. Although magnetic resonance spectroscopy (MRS) is considered the gold standard, it has a few limitations. The role of diffusion-weighted imaging (DWI), which is a simpler sequence, in the diagnosis and grading of fatty liver is not well studied. The aim of the study was to investigate the value of DWI in the diagnosis and grading of hepatic steatosis in patients with NAFLD. MATERIALS AND METHODS: Fifty-one adults (mean age: 38 years; 28 men, 23 women) with NAFLD, diagnosed clinically and by ultrasonography (USG), were included in the study after obtaining informed consent and approval from the institute ethics committee. USG was performed for grading of hepatic steatosis in all patients, followed by magnetic resonance imaging with DWI and MRS, on a 1.5T scanner. The mean apparent diffusion coefficient (ADC) values and proton density fat fraction (PDFF) were calculated, and MRS was used as the gold standard. The mean ADC values were compared with the PDFF and USG grades. RESULTS: There was a weak correlation between ADC values and PDFF (r = -0.36; P < 0.05). In addition, there was a weak correlation between the ADC values of the liver and USG grade (r = -0.34; P < 0.05). However, an overall increase in USG grades and PDFF was associated with decrease in the mean ADC value (P < 0.001). CONCLUSION: DWI is not accurate in the diagnosis and grading of hepatic steatosis in patients with NAFLD. However, a significant increase in fat deposition in the liver lowers the ADC values.
RESUMO
AIM: The aim of this study was to study the role of magnetic resonance imaging (MRI) in monitoring hepatic fat content in cases of nonalcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS: 41 adults (mean age: 39 years, 22 males; 19 females) with NAFLD were included after obtaining approval from the institutional ethics committee. The baseline clinical (weight, body mass index [BMI]) and biochemical parameters, fatty liver grade on ultrasonography (USG), and hepatic fat signal fraction (FSF) using dual-echo chemical shift imaging and proton density fat fraction on magnetic resonance spectroscopy (MRS-PDFF) were assessed, before and after intervention (dietary and lifestyle changes and oral vitamin E for six months). They were categorized into Group A (good compliance to intervention) and Group B (poor compliance), and the clinical and imaging parameters were compared between them. RESULTS: After intervention, Group A (n = 30) showed significant reduction in BMI (28.35 ± 3.25 to 27.14 ± 3.24 kg/m2; P < 0.001), hepatic FSF (19.30 ± 9.09% to 11.18 ± 7.61%; P < 0.05), and MRS-PDFF (18.79 ± 8.53% to 10.64 ± 6.66%). In Group B (n = 11), there was significant increase in BMI (28.85 ± 2.41 to 29.31 ± 2.57 kg/m2; P < 0.001), hepatic FSF (18.96 ± 9.79% to 21.48 ± 11.80%; P < 0.05), and reduction in high-density lipoproteins (P < 0.05). Although there was good correlation between USG and MRS in quantifying liver fat (r = 0.84-0.87; P < 0.001), USG was unable to detect <5.3% change in hepatic fat. There was poor correlation between lipid profile and MRS-PDFF. Change in body weight significantly correlated with change in hepatic fat content (r = 0.76; P < 0.001). CONCLUSION: MRI is useful in accurately quantifying and in monitoring hepatic fat content and is better than clinical and biochemical parameters and USG.
RESUMO
Sedation in locations outside the operating room (OR) is common. Guidelines for safe patient monitoring have been updated by the American Society of Anesthesiology to include monitoring of ventilation and/or carbon dioxide (CO2). Although technologies exist to monitor these variables, the quality and/or availability of these measurements in non-OR settings is not optimal. This quality improvement project assessed the value of impedance technology for monitoring minute ventilation (MV) compared to standard end-tidal monitoring of CO2 (ETCO2). Patients undergoing GI exams with moderate sedation provided by anesthesia providers were monitored for MV with a respiratory volume monitor (ExSpiron 1Xi, Respiratory Motion, Waltham, MA) and ETCO2 via nasal cannula (NC). Calibration and baseline data were collected prior to sedation. Continuous MV and ETCO2 data were collected and averaged, providing minute values after sedation medications throughout the procedure. Stable periods of reduced MV were averaged and used in comparison to ETCO2. Data from 20 patients were evaluated. After sedation, the expected decrease in MV after sedation was observed in 18 of 20 patients (average -47.82 %), while an increase in ETCO2 was observed in just 10 of 20 patients (average -5.17 mm Hg). The correlation coefficient between changes in MV and ETCO2 in response to sedation administration was positive and not significant, r = 0.223. Ventilation monitoring may provide an element of safety for earlier and more reliable detection of reduced ventilation compared to a surrogate for hypoventilation, ETCO2, in patients undergoing sedation for GI procedures outside of the OR.
