Assessment Of Signal Intensity Research Articles

OP05.10: Fetal magnetic resonance imaging (MRI) versus 3D ultrasonography (3D‐US) in assessment of fetal lung volumes in cases at risk of pulmonary hypoplasia

To analyse the correlation and agreement between 3D-US & MRI in measuring fetal lung volumes in cases at risk of developing pulmonary hypoplasia. 38 fetuses at high risk of developing lung hypoplasia either due to extrathoracic causes like renal anomalies causing oligohydraminos and skeletal dysplasias with narrow chest (22cases) or due to intrathoracic causes like congenital cystic adenomatoid malformation (CCAM) and congenital diaphragmatic hernia (CDH) (16 cases) were involved in a cross sectional study. 3D volume data sets of the fetal lungs were acquired were using a commercially available ultrasound system & total lung volumes were calculated using the virtual organ computer-aided analysis (VOCAL) method. MRI obtained fast T2 weighted images of fetal chest in axial, coronal and sagittal planes with assessment of signal intensity & lung volumetry. Comparison between mean lung volumes was performed using unpaired t test. Agreement between the 3D-US and MRI methods was done using Cohen Kappa test. Finally sensitivity, specificity, positive predictive value, negative predictive value & diagnostic accuracy were calculated for 3D-US and for MRI. Good agreement was detected between the two methods(Kappa = 0.715, p = 0.001). The measured lung volumes by 3D-US were smaller than those measured by MRI (p >0.05, non-significant). MRI showed greater specificity, positive predictive value and diagnostic accuracy (100%each) than 3D-US (68.75,78.26 &82.86%) respectively. There is good concordance between 3D-US and MRI in measuring lung volumes and in assessment of pulmonary hypoplasia. MRI can be used complementary to US in borderline cases of pulmonary hypoplasia and in difficult diagnostic situations due to complicated lesions or due to technical problems as in cases of severe oligohydraminos & improper fetal position.

MRI and three dimensional ultrasonography in the assessment of pulmonary hypoplasia in fetuses with urinary tract anomalies

PurposeTo analyze the correlation and agreement between three dimensional (3D) US and MRI in the assessment of pulmonary volumes of fetuses with different types of urinary tract malformations (UTM) and high-risk of pulmonary hypoplasia (PH). Patients and methodsThirty-nine fetuses with various UTM, at risk for PH were involved in this cross-sectional study. 3D volume US data sets of the fetal lungs were acquired. The right, left and total lung volumes were calculated separately using the virtual organ computer-aided analysis (VOCAL) method with a 30° rotation. MRI of fetal lung was obtained with assessment of signal intensity and lung volumetry. Comparison between mean lung volumes was performed using unpaired t test. Agreement between the 3D-US and MRI methods was done using Cohen kappa test. ResultsGood agreement was detected between the two methods (Kappa=0.629, p=0.001). The measured lung volumes by 3D-US were smaller than those measured by MRI (p>0.05, non-significant). MRI showed greater specificity, PPV and diagnostic accuracy (100% each) than 3D-US (50%, 88.9% and 90% respectively). ConclusionThere is a good concordance between 3D-US and MRI in the evaluation of PH in fetuses with UTM. MRI could be reserved for borderline cases of pulmonary hypoplasia and the difficult diagnostic situations.

MRI of normal and pathological fetal lung development

Normal fetal lung development is a complex process influenced by mechanical and many biochemical factors. In addition to ultrasound, fetal magnetic resonance imaging (MRI) constitutes a new method to investigate this process in vivo during the second and third trimester. The techniques of MRI volumetry, assessment of signal intensities, and MRI spectroscopy of the fetal lung have been used to analyze this process and have already been applied clinically to identify abnormal fetal lung growth. Particularly in conditions such as oligohydramnios and congenital diaphragmatic hernia (CDH), pulmonary hypoplasia may be the cause of neonatal death. A precise diagnosis and quantification of compromised fetal lung development may improve post- and perinatal management. The main events in fetal lung development are reviewed and MR volumetric data from 106 normal fetuses, as well as different examples of pathological lung growth, are provided.

13C nuclear magnetic resonance spectroscopic analysis of the triacylglycerol composition ofBiota orientalis and carrot seed oil

Abstract13C nuclear magnetic resonance (NMR) spectroscopic analysis of the whole oil (triacylglycerols) ofBiota orientalis seeds confirms the presence of oleate [18:1(9Z)], linoleate [18:2(9Z, 12Z)], linolenate [18:3((9Z, 12Z, 15Z)], 20:3 (5Z, 11Z, 14Z), 20:4(5Z, 11Z, 14Z, 17Z), and saturated fatty acids in the acyl groups by comparing the observed carbon shifts with previously established shift data for model triacylglycerols. This technique shows that the saturated, 20:3 and 20:4 fatty acids are distributed mainly in the α‐acyl positions, whereas oleate, linoleate, and linolenate are randomly acylated to the α‐ and β‐positions of the glycerol “backbone”. Stereospecific hydrolysis of theBiota oil with pancreatic lipase, followed by chromatographic analysis of fatty esters, reveals the presence of trace amounts of 16:0(0.7%), 18:0(0.5%), 20:3 (0.4%), and 20:4 (1.3%) in the β‐position of the glycerol “backbone”, which are undetectable by13C NMR technique on the whole oil. Semiquantitative assessment of the13C NMR signal intensities gives the relative percentages of the fatty acid distribution as: saturated 16:0, 18:0 (12.0% α‐acyl), oleate (7.7% α‐acyl 8.7% β‐acyl), total linoleate and linolenate (31.7% α‐acyl; 24.2% βacyl), total 20:3 and 20:4 (15.7% α‐acyl). The13C NMR spectroscopic analysis of carrot seed oil identifies the presence of saturated (18:0), 18:1(6Z), 18:1(9Z), and 18:2(9Z, 12Z). The saturated fatty acid is found in the α‐acyl positions. Semi‐quantitative assessment of the signal intensities gives the relative percentages of the fatty acids as: 18:0 (4.5% α‐acyl), 18:1(6Z) (49.6% α‐acyl; 19.7% β‐acyl), oleate (6.5% α‐acyl; 8.6% β‐acyl) and linoleate (5.2% α‐acyl; 6.9% β‐acyl).