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Purpose:To evaluate morphological and signal intensity (SI) changes of placental insufficiency on magnetic resonance imaging (MRI) and to assess morphological changes and decreased flow voids (FVs) on T2-weighted rapid acquisition with relaxation enhancement (RARE) images for diagnosing placental insufficiency.Methods:Fifty singleton fetuses underwent MRI using a 1.5-T MR scanner. Placental thickness, area, volume, SI, amniotic fluid SI, and size of FVs between the uterus and the placenta were measured on MR images. Two radiologists reviewed T2-weighted RARE images for globular appearance of the placenta and FVs between the uterus and the placenta. Data were analyzed using t-tests, McNemar’s tests, and areas under the receiver operating characteristic curve (AUCs) at 5% level of significance.Results:Twenty-five of the 50 pregnancies were categorized as having an insufficient placenta. Significant differences were observed between insufficient and normal placentas in mean placental thickness, area, volume, placenta to amniotic fluid SI ratio, and size of FVs (49.0 mm vs. 36.9 mm, 1.62 × 104 mm2 vs. 2.67 × 104 mm2, 5.13 × 105 mm3 vs. 6.56 × 105 mm3, 0.549 vs. 0.685, and 3.4 mm vs. 4.3 mm, respectively). The sensitivity and accuracy using globular appearance plus decreased FVs were greater than those using decreased FVs (P < 0.01). There was no significant difference among AUCs using globular appearance and decreased FVs, and globular appearance plus decreased FVs.Conclusions:Placental insufficiency was associated with placental thickness, area, volume, placenta to amniotic fluid SI ratio, and size of FVs. Evaluating FVs on T2-weighted RARE images can be useful for detecting placental insufficiency, particularly in placentas without globular appearance on MR images.

Purpose: To evaluate motion artifacts, tissue contrasts, and lesion detectability in the neck with the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) (BLADE) technique. Materials and Methods:A total of 46 patients referred for MRI of the neck were included in a comparison of T2-weighted BLADE (T2W-BLADE) sequence and T2W fast spin-echo (T2W-FSE) sequence. All examinations were performed at 3T using the same parameters. Two observers evaluated unlabelled images for motion artifacts, the preferred image quality, and lesion detectability. Region of interest (ROI)-based quantitative measurements were performed to assess tissue contrasts. The frequency of occurrence of the different assessed artifacts and the lesion detectability was tested using McNemar's test. Tissue contrasts were compared using the Wilcoxon paired test. Reader agreement was assessed using kappa test.Results: T2W-BLADE showed less ghosting and pulsation artifacts than T2W-FSE (P < 0.01). T2W-BLADE images were rated as better than or equal to T2W-FSE images in majority cases (93.5%; kappa ¼ 0.64). There was not significant difference in tissue contrasts between T2W-BLADE and T2W-FSE. A total of 32 lesions were present in 32 patients and equally well seen on T2W-BLADE and T2W-FSE.Conclusion: T2W-BLADE can reduce motion artifacts and provide tissue contrasts and lesion detectability equivalent to T2W-FSE. ALTHOUGH T2-WEIGHTED fast spin-echo (T2W-FSE) magnetic resonance (MR) sequences are sensitive for the detection of some types of pathologic conditions, they have the disadvantage of relatively long acquisition times (1). This can lead to degradation of images in the neck as a result of swallowing, tongue movement, and upper chest wall movement.The periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) (BLADE) MR technique can reduce artifacts induced by in plane rotation and translational head motion using an alternative way of sampling k-space (2-9). Unlike rectilinear k-space sampling, this method acquires multiple echo trains of a turbo spin echo (TSE) in a rotating partially overlapping fashion, so-called BLADES.The BLADE technique has the advantage of central k-space oversampling, so that image artifacts are greatly reduced in the brain and the upper abdomen (2-4,7-10). On the other hand, it is not yet evaluated that the BLADE sequence at 3 T can reduce motion artifacts in the neck region. The aim of this study was to compare T2W BLADE sequence with T2W FSE sequence in the neck, with an evaluation of the presence of motion artifacts, tissue contrasts, and lesion detectability. MATERIALS AND METHODS PatientsFrom April 2007 through October 2007, we performed a prospective intraindividual study in patients who were referred for MRI of the neck. We included 46 consecutive patients (31 men, 15 women; mean age ¼ 57.2 years) referred for MRI of the neck in a comparison of T2W BLADE and T2W FSE.The study design was approved by our institutional review board, and all patients ga...

The CT features of poor contrast enhancement, thin rim enhancement, and dark fan sign are valuable for identifying acute torsion of USL.

JPEG compression at ratios of 10:1 and 20:1 was tolerated in the detection of acute cerebral infarction at CT.

IntroductionThe clinical use of cardiac magnetic resonance imaging MRI has increased in recent years, especially for whole-heart coronary MR angiography and the identi cation of myocardial ischemia by perfusion study. The functional cardiac exam is a fundamental method for many cardiac MRI investigations. This exam can be performed using either the steady-state free precession SSFP or fast low angle shot FLASH method.The FLASH technique-based gradient echo sequence was introduced in 19861 . The features of this sequence are RF pulse with low ip angle, short repetition time 2-20 msec 2 , and a spoiler pulse that can reduce the effect of residual transverse magnetization 3 . The SSFP sequence is also a gradient echo sequence with low ip angle and short Abstract : This study compared steady-state free precession SSFP with Fast Low Angle Shot FLASH at 3.0 T cardiac Cine MRI with respect to contrast to noise ratio CNR and visual image quality assessment. All images were acquired on a 3.0-T Siemens MAGNETOM trio. Seven healthy volunteers all males, mean age 32.5 7.1 years underwent magnetic resonance imaging using SSFP and FLASH sequence on the same day. For both SSFP and FLASH imaging, 8-mm thick short axis and long axis views were acquired with equal matrix size 192 192 . CNR calculations were performed on the short axis images acquired at end systole time points. Three radiologists independently assessed image quality. SSFP images were superior to FLASH images with respect to CNR SSFP : 7.14 2.16, FLASH : 3.57 1.83, P 0.001 . In image quality, SSFP images were superior to FLASH in both short and long axis views P 0.01 . Although SSFP images contained dark blood artifacts in 3 cases, these images were improved by frequency offset. SSFP sequences provided higher quality images than FLASH sequences, and would be available for cardiac cine MRI at 3.0 T. [5][6][7] . At 3.0 T, the higher field strength enables a higher signal to noise ratio SNR and contrast to noise ratio CNR . However, the SSFP sequence is more limited by the specific absorption rate SAR or specific artifact, and SAR increases with field strength. The rst solution to this problem is to decrease the ip angle, but this worsens contrast [8][9][10] . At 3.0 T cine MRI, SSFP is reportedly slightly superior to FLASH sequence in terms of CNR and visual image quality assessment 11 , but 3.0 T MRI has been improved in terms of susceptibility or sequence optimization since that study.This study compared SSFP and FLASH sequence images with respect to CNR, the presence of artifacts and visual image quality at 3.0 T MRI. Materials and MethodsSeven volunteers mean age 32.5 7.1 years, age range 25-42 years, all males without any known history of diabetes, hypertension, renal failure, or cardiac disease were enrolled in this study. All examinations were performed using a 3.0-T MRI system MAGNETOME Trio A Tim System ; Siemens Medical Solutions, Erlangen, Germany with a 6-ch balance coil and 6-ch spinal balance coil. The parameters for the SSFP sequence were as follows :

: We evaluated clinical outcomes and prognostic factors associated with survival after balloon-occluded retrograde transvenous obliteration B-RTO of gastric varices in patients with portal hypertension. Of 50 patients with gastric varices who underwent B-RTO, 46 94.0% patients in whom B-RTO was technically successful were reviewed retrospectively. Gastric and esophageal varices after B-RTO were evaluated by contrast-enhanced computer tomography and endoscopy, respectively. Liver function parameters and Child-Pugh scores were estimated before and at 1 year after B-RTO. The cumulative survival rate was calculated, and univariate and multivariate analyses were used to assess the prognostic factors. No major complications occurred in any of the patients following B-RTO and no recurrence or bleeding of gastric varices was noted. Of the 42 patients who were followed up for the progression of esophageal varices, 13 31.0% had worsened varices and of these, 6 14.3% showed bleeding. Prothrombin activity had signi cantly improved at 1 year after B-RTO, although there were no changes in other liver function parameters. The overall cumulative survival rates at 1, 3, and 5 years after B-RTO were 91.6%, 70.9%, and 53.6%, respectively. Multivariate analysis identified the occurrence of advanced hepatocellular carcinoma HCC during the observation period as a prognostic factor for survival hazard ratio 4.1497, 95% CI 1.32314 13.0319, P 0.0148 . B-RTO of gastric varices is an effective treatment ensuring lower recurrence and bleeding rates ; however, these patients require careful observation for progression of esophageal varices. The management of HCC is crucial for achieving long-term survival after B-RTO.

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