ABSTRACT
<p><b>BACKGROUND</b>Evaluation of fetal central nervous system (CNS) agenesis by ultrasonography (US) is frequently limited, but magnetic resonance imaging (MRI) has its own advantages and is gaining popularity in displaying suspected fetal anomalies. The purpose of this study was to explore the value of MRI in detecting fetal CNS agenesis.</p><p><b>METHODS</b>Thirty-four women (aged from 22 to 35 years, average 27 years) with complicated pregnancies (16 - 39 weeks of gestation, average 30 weeks) were examined with a 1.5 T superconductive MR unit within 24 hours after ultrasonography. Half-Fourier acquisition single-shot turbo spin-echo (HASTE) T(2)-weighted imaging (T(2)WI) sequence were performed in all patients, and fast low angle shot (FLASH) T(1)-weighted imaging (T(1)WI) sequence were applied sequentially in seven of them. Comparison of the results was made between the MRI and US findings as well as autopsy or postnatal follow-up MRI findings.</p><p><b>RESULTS</b>The gyrus, sulcus, corpus callosum, thalamus, cerebellum, brainstem, and spinal cord of fetus were shown more clearly on T(2)-weighted MR images than on T(1)-weighted MR images. MRI corrected the diagnosis of US in 10 cases (10/34, 29.41%) and the diagnosis was missed only in 1 case (1/34, 2.94%).</p><p><b>CONCLUSION</b>MRI has advantages to US in detecting fetal CNS anomalies and is a supplement to US in complicated pregnancies.</p>
Subject(s)
Adult , Female , Humans , Pregnancy , Central Nervous System , Congenital Abnormalities , Diagnostic Imaging , Magnetic Resonance Imaging , Methods , Ultrasonography, PrenatalABSTRACT
Objective To evaluate the role of CT and MR/in the diagnosis of posterior reversible encephalopathy syndrome(PRES).Methods Eight women with PRES(6 pregnant women,1 case after chemotherapy,and 1 patient with hypertension)were enrolled in our study.All of them had MR imaging (T_1WI,T_2WI,FLAIR,DWI),and five cases underwent post-contrast T_1WI and three dimensional contrast enhanced MR angiography(3D CEMRA).Two cases also had CT scan.Results MRV in all 8 patients showed no evidence of stenosis,dilation,or thrombosis in cranial veins and sinuses.MRI demonstrated multiple lesions located in bilateral parieto-occipital lobes(8 cases),bilateral basal ganglia(2 cases),and bilateral frontal lobes(4 cases).The lesions were prominent within white matter,some of them involved gray matter(3 cases).Lesions appeared as hyperintense signals on FLAIR and T_2-weighted images, isointense or mildly hypointense signals on T_1-weighted images,normal or decreased intensity on DWI,and isointensity or hyperintensity on apparent diffusion coefficient(ADC)maps.Post-contrast T_1WI showed mild reversible enhancement and 3D CEMFdisplayed numerous reversible“grape-like”enhancements in terminal arterial branches along the middle cerebral artery(MCA),anterior cerebral artery(ACA)and posterior cerebral artery(PCA).Follow-up scan showed decreased abnormal signals.Conclusion Lesions of PRES are usually located in parieto-occipital lobes,especially in white matter,but they can also be seen in frontal lobes and basal ganglia bilaterally.Post-contrast T_1WI and 3D enhanced MRA can provide useful information in the manifestation of reversible enhancement.MRI has advantages to display lesion in PRES,