Single-shot Rapid Acquisition Research Articles

Quantitative Assessment of Peripheral Oxidative Metabolism With a New Dynamic 1H MRI Technique: A Pilot Study in People With and Without Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is linked to impaired mitochondrial function. Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is a gadolinium-contrast-free 1H method to assess mitochondrial function by measuring low-concentration metabolites. A CEST MRI-based technique may serve as a non-invasive proxy for assessing mitochondrial health. A 1H CEST MRI technique may detect significant differences in in vivo skeletal muscle phosphocreatine (SMPCr) kinetics between healthy volunteers and T2DM patients undergoing standardized isometric exercise. Cross-sectional study. Seven subjects without T2DM (T2DM-) and seven age, sex, and BMI-matched subjects with T2DM (T2DM+). Single-shot rapid acquisition with refocusing echoes (RARE) and single-shot gradient-echo sequences, 3 T. Subjects underwent a rest-exercise-recovery imaging protocol to dynamically acquire SMPCr maps in calf musculature. Medial gastrocnemius (MG) and soleus SMPCr concentrations were plotted over time, and SMPCr recovery time, , was determined. Mitochondrial function index was calculated as the ratio of resting SMPCr to . Participants underwent a second exercise protocol for imaging of skeletal muscle blood flow (SMBF), and its association with SMPCr was assessed. Unpaired t-tests and Pearson correlation coefficient. A P value <0.05 was considered statistically significant. SMPCr concentrations in MG and soleus displayed expected declines during exercise and returns to baseline during recovery. was significantly longer in the T2DM+ cohort (MG 83.5 ± 25.8 vs. 54.0 ± 21.1, soleus 90.5 ± 18.9 vs. 51.2 ± 14.5). The mitochondrial function index in the soleus was significantly lower in the T2DM+ cohort (0.33 ± 0.08 vs. 0.66 ± 0.19). SMBF was moderately correlated with the SMPCr in T2DM-; this correlation was not significant in T2DM+ (r = -0.23, P = 0.269). The CEST MRI method is feasible for quantifying SMPCr in peripheral muscle tissue. T2DM+ individuals had significantly lower oxidative capacities than T2DM- individuals. In T2DM, skeletal muscle metabolism appeared to be decoupled from perfusion. 1 TECHNICAL EFFICACY: Stage 1.

Real-Time Magnetic Resonance Imaging.

Real-time magnetic resonance imaging (RT-MRI) allows for imaging dynamic processes as they occur, without relying on any repetition or synchronization. This is made possible by modern MRI technology such as fast-switching gradients and parallel imaging. It is compatible with many (but not all) MRI sequences, including spoiled gradient echo, balanced steady-state free precession, and single-shot rapid acquisition with relaxation enhancement. RT-MRI has earned an important role in both diagnostic imaging and image guidance of invasive procedures. Its unique diagnostic value is prominent in areas of the body that undergo substantial and often irregular motion, such as the heart, gastrointestinal system, upper airway vocal tract, and joints. Its value in interventional procedure guidance is prominent for procedures that require multiple forms of soft-tissue contrast, as well as flow information. In this review, we discuss the history of RT-MRI, fundamental tradeoffs, enabling technology, established applications, and current trends. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 1.

A fast multislice sequence for 3D MRI-CEST pH imaging.

PurposeChemical exchange saturation transfer MRI can provide accurate pH images, but the slow scan time (due to long saturation periods and multiple offsets sampling) reduce both the volume coverage and spatial resolution capability, hence the possibility to interrogate the heterogeneity in tumors and organs. To overcome these limitations, we propose a fast multislice CEST‐MRI sequence with high pH accuracy and spatial resolution.MethodsThe sequence first uses a long saturation pulse to induce the steady‐state CEST contrast and a second short saturation pulse repeated after each image acquisition to compensate for signal losses based on an uneven irradiation scheme combined with a single‐shot rapid acquisition with refocusing echoes readout. Sequence sensitivity and accuracy in measuring pH was optimized by simulation and assessed by in vitro studies in pH‐varying phantoms. In vivo validation was performed in two applications by acquiring multislice pH images covering the whole tumors and kidneys after iopamidol injection.ResultsSimulated and in vivo data showed comparable contrast efficiency and pH responsiveness by reducing saturation time. The experimental data from a homogeneous, pH‐varying, iopamidol‐containing phantom show that the sequence produced a uniform CEST contrast across slices and accurate values across slices in less than 10 minutes. In vivo measurements allowed us to quantify the 3D pH gradients of tumors and kidneys, with pH ranges comparable with the literature.ConclusionThe proposed fast multislice CEST‐MRI sequence allows volumetric acquisitions with good pH sensitivity, accuracy, and spatial resolution for several in vivo pH imaging applications.

A peek into the uterus – MRI of the fetal CNS

The purpose of this article is to provide an overview of MR imaging of the fetal central nervous system, and to briefly discuss recent advances. Fetal MRI has been commonly used throughout the world for over 20 years. Compared to US it has better contrast resolution, allows direct visualization of both hemispheres and the additional limitations of sonography do not affect the quality of MRI. There are no known adverse short-term or long-term side effects of MRI in children, who were imaged in the fetal period. The standard protocol for fetal MRI consists of single-shot rapid acquisition T2 weighted sequences in three planes, fast spoiled gradient recalled T1 weighted sequence, T2 gradient echo sequence and diffusion weighted sequence in the axial plane. The clinical applications of advanced MRI techniques are still limited. Fetal MRI is performed to confirm abnormalities detected on US, and to exclude additional pathology. Interpreting fetal MRI images requires understanding of normal fetal CNS development and one should also evaluate other fetal structures, the umbilical cord and placenta. The most common indication for MR imaging of the fetal CNS is mild ventriculomegaly. Other common indications, that are also discussed in the article, include commissural abnormalities, infratentorial abnormalities, cortical malformations, spinal pathology and complications of monochorionic twin pregnancy. Conclusion : Fetal MRI provides important information in prenatal counseling, therefore familiarity with the applications and limitations of fetal MRI, and multidisciplinary collaboration remain essential for the radiologist involved in prenatal imaging.

Clinical applications of high-resolution ocular magnetic resonance imaging

Magnetic resonance imaging (MRI) using fast sequences with subjects staring at a target can provide motion-free ocular images, and small receiver surface coils make it possible to produce ocular images with high spatial resolution. MRI using half-Fourier single-shot rapid acquisition with a relaxation enhancement sequence as a fast T2-weighted imaging yields useful images for the morphologic diagnosis of ocular diseases, and MRI using a fast spoiled gradient-recalled-echo sequence as a T1-weighted imaging yields additional information by the administration of gadolinium-based contrast material for assessing the vascularity of intraocular tumors. These ocular imaging techniques are useful for the evaluation of patients with angle closure glaucoma, congenital abnormality of ocular globes, intraocular tumors and several types of detachments, as well as patients after ocular surgery. In this pictorial essay, we demonstrate the clinical applications of fast high-resolution ocular MRI with fixation of the subjects' visual foci.

Magnetic resonance imaging-determined subretinal fluid volume in an uveitic patient.

To describe the usefulness of the magnetic resonance imaging-determined subretinal fluid volume to evaluate the therapeutic effect on the retinal detachment caused by uveitis with the clouded media. We obtained the images by half-Fourier single-shot rapid acquisition with relaxation enhancement magnetic resonance imaging using a microscopy coil. We measured the area of subretinal fluid on each image and calculated the volume of subretinal fluid by multiplying the total area by the slice thickness. A 56-year-old male who had lost his central visual field developed bullous retinal detachment in both eyes associated with uveitis. We treated him with steroid pulse therapy. We could not accurately evaluate the improvement of retinal detachment by ophthalmoscopy and ultrasonography as a result of the clouded media. We measured the volume of the subretinal fluid using magnetic resonance imagings. The volume of the subretinal fluid was observed to gradually decrease. These methods enable us to obtain clear magnetic resonance images within 2 seconds per slice. The reproducibility of the volumetry obtained by magnetic resonance imaging was excellent. The adaptation of half-Fourier single-shot relaxation enhancement imaging performed with a surface coil makes it possible to evaluate the volumetry of a targeted space while also being useful for evaluating the effect of the treatment.

OP05.05: Validity and reliability of fetal brain MRI in ventricular volume measurement

Objectives: Fetal magnetic resonance (MR) has greatly improved the ability to counsel patients with fetal diagnosis of ventriculomegaly, since it allows accurate study of the lateral ventricles as well as the whole brain structure in search for additional anomalies. Quantitative MR indices along with qualitative assessment may certainly improve the diagnostic utility of MR to predict postnatal outcomes. Our aim was to assess inter and intraobserver variability in determining fetal lateral ventricle volume using brain MR in fetuses referred for ventriculomegaly (VM). Methods: Lateral ventricle volumes were measured by using planimetry on single-shot rapid acquisition with relaxation enhancement MR images obtained in 30 fetuses with sonographically diagnosed VM (atrial width between 10 and 28 mm). All fetuses aged between 20 and 26 gestational weeks. Exams were performed in a Sonata Maestro Class 1,5-T system (Siemens, Erlangen, Germany) and measurements attained in a Leonardo workstation using ARGUS VA60C software. Ventricular volumes were independently assessed (60 ventricles) in the coronal section plane by two experienced observers, twice by the first observer with at least 1 month of interval between measurements. Reliability and agreement of the volumes were evaluated with intraclass correlation coefficients (ICCs), and proportionate Bland-Altman plots were constructed. Results: Inter and intraobserver analysis showed good agreement between measurements, as shown on the dispersion and BlandAltman plots (most of the measurements were within the mean ±2 SD). ICC was 0.999 for both intra and interobserver (95% CI: 0.999; 1.000; and mean of differences was 0.01 (95% LA: ±2.26; SD: ±1.15) and 0.26 (95% LA: ±1.28 and SD: ±0.65) respectively. Conclusions: Fetal lateral ventricle volume can be readily assessed during the second and third trimesters of gestation. The reliability and validity of MR volume measurements are high, with very good interobserver agreement.

Optimal fast T2‐weighted magnetic resonance microscopy imaging of the eye and its clinical application

To compare a half-Fourier single-shot rapid acquisition with relaxation enhancement (RARE) sequence with a balanced steady-state free precession (b-SSFP) sequence in the evaluation of the eye using magnetic resonance (MR) microscopy imaging and to clarify the usefulness of RARE microscopy imaging in evaluating nonoperative glaucoma patients and patients who have undergone surgery for glaucoma or cataract. One-mm and 2-mm slice thickness images of RARE sequence and b-SSFP sequence using a 1.5 T MR unit and a 23-mm microscopy coil were obtained in eight healthy volunteers. The signal-to-noise (S/N) ratio of aqueous humor in the anterior chamber was measured quantitatively and visualization of the anterior chamber anatomy was assessed qualitatively. Furthermore, we evaluated 21 glaucoma patients (including six postoperative patients) and four patients after cataract surgery with 2-mm slice thickness RARE MRI. The 2-mm slice thickness RARE imaging had a significantly greater S/N ratio than the 1-mm slice thickness RARE imaging (P < 0.05) and acquired the best image quality among the four types of images (P < 0.01). Additionally, 2-mm slice thickness RARE microscopy imaging could depict anterior chamber anatomy of glaucoma eyes and eyes after cataract surgery. We believe that optimal fast T2-weighted MR microimaging might become a useful ophthalmologic examination technique.

Anterior Chamber Configuration in Patients with Glaucoma: MR Gonioscopy Evaluation with Half-Fourier Single-Shot RARE Sequence and Microscopy Coil

The purpose of the study was to determine the accuracy of half-Fourier single-shot rapid acquisition with relaxation enhancement high-spatial-resolution magnetic resonance (MR) imaging performed with a microscopy coil in the diagnosis of narrow anterior chamber angle in patients with glaucoma. Slit-lamp biomicroscopy served as the reference standard. The institutional review board approved this study, and written informed consent was obtained from the 20 recruited patients. There was excellent agreement between MR gonioscopy and slit-lamp biomicroscopy in the classification of anterior chamber angles as narrow or open (kappa = 0.89 [95% confidence interval: 0.69, 1.10]). MR gonioscopy has substantial potential as a technique used to evaluate glaucoma.

Frequency of Common Bile Duct Motion Artifacts Caused by Inferior Vena Cava Pulsation on Magnetic Resonance Cholangiopancreatography

We assessed the frequency of common bile duct (CBD) motion artifacts caused by inferior vena cava (IVC) pulsation on magnetic resonance cholangiopancreatography (MRCP). We retrospectively evaluated CBD motion artifacts in 4 MRCP sequences from each of 115 consecutive patients. We observed 37 (32.2%) ghost artifacts at the ventral and dorsal aspects of the CBD on transaxial, half-Fourier acquisition single-shot turbo spin-echo (HASTE-ax) images; no such artifacts were observed on transaxial T(2)-weighted turbo spin-echo images. In 10 patients, we observed 9 (7.8%) pseudo-defects of the CBD on 3-dimensional T(2)-weighted turbo spin-echo with navigator-triggered prospective acquisition correction technique MRCP and 6 (5.2%) pseudo-defects on single-shot rapid acquisition with relaxation enhancement MRCP. Pseudo-defects were significantly more frequent in patients with ghost artifacts than without (9 of 37 [24.3%] versus one of 78 [1.3%]; P<0.01, McNemar test). Although uncommon, pseudo-defects of the CBD caused by IVC pulsation are observed on MRCP. MRCP interpretation that includes comparison with HASTE-ax images can diminish the potential misinterpretation of such CBD motion artifact as bile duct tumor or biliary stone.

Magnetic resonance cholangiography of biliary strictures after liver transplantation: A prospective double‐blind study

To compare magnetic resonance cholangiography (MRC) with endoscopic retrograde cholangiography (ERC) in quantitatively evaluating biliary strictures in liver transplant recipients. Eight liver transplant recipients with suspected biliary complications were referred for ERC and also underwent MRC within 24 hours using a combination of single-shot rapid acquisition with relaxation enhancement (SS-RARE) and three-dimensional (3D)-RARE sequences. The studies were independently interpreted by two blinded radiologists and a single blinded endoscopist who recorded the presence of a stricture and/or upstream dilatation, the ratio of recipient-to-donor duct diameters at the anastomosis, as well as the proximal duct diameter, length, and percent stenosis of any stricture detected. Using ERC as the standard of reference, MRC had a sensitivity and negative predictive value of 100%, mean specificity of 83.3%, and mean positive predictive value of 92.9% in the detection of six strictures. Compared with ERC, MRC obtained accurate measurements of recipient-to-donor duct diameter ratios (r, 0.91; P < 0.01), proximal duct diameters (r, 0.83, P < 0.05), stricture lengths (r, 0.58; P = 0.06), and percent stenosis (r, 0.78; P = 0.06). MRC can provide equivalent imaging to ERC and can reliably identify and quantitatively evaluate biliary strictures in post-orthotopic liver transplantation (OLT) patients.

Magnetic resonance cholangiography: comparison of two- and three-dimensional sequences for assessment of malignant biliary obstruction

The purpose was to retrospectively compare two-dimensional (2D) magnetic resonance cholangiography (MRC) including breath-hold single-shot rapid acquisition with relaxation enhancement (RARE) and multislice half-Fourier RARE versus navigator-triggered 3D-RARE MRC in the evaluation of biliary malignancy. MRC findings were evaluated in 31 patients with malignant biliary obstruction, including biliary malignancy, gallbladder carcinoma, and ampullary cancer. Two observers independently reviewed the images to assess the overall image quality, artifacts, ductal conspicuity, extent of disease, diagnostic confidence of tumor extent, and origin of tumor. The results were compared with surgical and histopathologic findings. Studies obtained with 3D-MRC were of significantly higher technical quality than those obtained with 2D-MRC. However, the accuracy between two sequences for classification of tumor showed no statistical significance. There was no significant difference between the Az values of 2D- and 3D-MRC for overall tumor extent in bilateral second order branch, intrapancreatic common bile duct (CBD) involvement (Az = 0.889, 0.881 for 2D and Az = 0.903, 0.864 for 3D). Nor was there a significant difference between two sequences in the assessment of the origin of tumor. Although 3D-MRC has superior image quality over 2D-MRC, 3D-MRC showed no statistically significant difference in accuracy compared with 2D-MRC for evaluating the extent of disease in malignant biliary obstructions.

Magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy, usually develops in patients with cirrhosis, growing sequentially from low-grade dysplastic nodules to frank malignant HCC. Its recognition is critical because curative treatment and prognosis require early diagnosis. Survival in patients with HCC relates directly to the number, size, and extent of lesions at diagnosis. Imaging of HCC is complicated because the tumor has a varied imaging appearance and frequently coexists with other cirrhotic nodules. Magnetic resonance imaging (MRI), the best available diagnostic technique, offers good contrast resolution and diagnostic sensitivity ranging from 33% to 77%. The main difficulty is not in diagnosing large tumors, but rather small tumors (<2 cm), because of considerable overlap on imaging between benign (regenerative), borderline (dysplastic), and malignant nodules. Increasing degrees of histological malignancy are associated with increasing arterialization and loss of portal blood supply; therefore, recognition of HCC requires dynamic imaging with gadolinium-enhanced T1-weighted sequence. Typically, HCC is a focal lesion with high signal intensity on T2-weighted images, variable signal intensity on T1-weighted images, intense arterial phase enhancement after gadolinium injection, and isointensity or hypointensity at the portal venous phase. The sensitivity of MRI for detecting small lesions is low, and improvement is still needed. Newer contrast agents, higher field strength (3 Tesla) imaging, and perfusion and diffusion MRI techniques possibly will provide greater sensitivity and specificity for detecting small HCCs in the future.

Cisterna chyli at routine abdominal MR imaging: a normal anatomic structure in the retrocrural space.

The cisterna chyli, a dilated lymphatic sac in the retrocrural space, represents the origin of the thoracic duct. It is seen in approximately half of lymphangiographic studies and 20% of autopsies. Highly fluid-sensitive magnetic resonance (MR) imaging sequences such as single-shot rapid acquisition with refocused echoes, which are currently used in many abdominal MR imaging protocols, frequently result in the depiction of this structure. The cisterna chyli was evident on abdominal MR images acquired in 30 (15%) of 200 consecutive patients who underwent MR imaging at the authors' institution between February and June 2002. Its appearance varied from that of a thick tube to that of a thin tube, parallel or converging tubes, tortuous tubes, a sausage-shaped fluid collection, a focal collection, or a focal plexus. Radiologists who perform MR imaging should be familiar with the various possible appearances of this normal anatomic structure so as not to mistake it for a pathologic entity.

MR pyelography in the assessment of hydroureteronephrosis: single-shot thick-slab RARE versus multislice HASTE sequences.

We used magnetic resonance (MR) pyelography to compare the value of thick-slab single-shot rapid acquisition with relaxation enhancement (RARE) sequence with that of multislice half-Fourier acquisition single-shot turbo-spin-echo (HASTE) sequence in evaluating the full spectrum of morphologic features in a group of patients with hydronephrosis. MR pyelographic images, with the use of thick-slab RARE and multislice HASTE sequences in 90 patients, were evaluated for image quality, presence of hydronephrosis, and level and cause of obstruction. HASTE sequences provided images of better quality than did RARE sequences (p < 0.001). There was no statistically significant difference in demonstrating the presence of hydronephrosis (p = 0.5) and level of obstruction (p = 0.125). Sensitivity, specificity, and accuracy in diagnosing cause of obstruction were 61.7%, 62.5%, and 62%, respectively, for RARE sequences and 80%, 82.5%, and 81%, respectively, for HASTE sequences, with a statistically significant difference (all p < 0.05). Multislice HASTE sequence provides better diagnostic information than does thick-slab RARE sequence, particularly in evaluating the cause of obstruction.

Calibrated magnetic resonance hydrometry: an in vitro study.

To demonstrate a quantitative approach to measuring fluid volumes with standard single shot RARE sequences. In phantom experiments, magnetic resonance hydrometry (MRH), in combination with various calibration phantoms (5 mL up to 500 mL) as internal standards, was used to quantify fluid volumes. In total, 16 volume phantoms were investigated with six different calibration phantoms. In addition, noise correction was implemented to correct the quantification results and to avoid the influence of random noise in the image. All MR measurements show significant correlations of up to r = 0.99 (P <.05) with the real applied volume in the investigated phantoms. However, measurements of large volumes were more precise with large calibration phantoms. Noise reduction did not change the correlation between measured and real applied volumes, but did reduce the error of the measured volumes. Calibrated magnetic resonance hydrometry (cMRH) is able to quantify volumes of fluid fast and noninvasively. The volumes of the used calibration phantoms have to be at least in the order of magnitude of the volumes that are to be measured. In vitro, cMRH using a single-shot rapid acquisition with refocused echoes (ssRARE) sequence and calibration phantoms is a fast and accurate method of quantifying steady amounts of fluid.

The use of ECG and respiratory triggering to improve the sensitivity of oxygen-enhanced proton MRI of lung ventilation.

Changes in lung signal between normal breathing and breathing pure oxygen is the basis for oxygen-enhanced ventilation MRI. An optimal technique guarantees a significant response to pure oxygen in well-ventilated lung tissue. To improve the sensitivity, we investigated the effect of ECG and respiratory triggering. Centric reordered single-shot rapid acquisition relaxation enhancement sequences (TE 4.2 ms, echo spacing 4.2 ms, bandwidth 650 Hz/pixel), with an inversion recovery preparation pulse (TI 700 ms), were used. Series of 20 measurements were performed with and without ECG and respiratory triggering in five young volunteers. Subsequently, series of 100 images were acquired during breathing normal air and pure oxygen (as "stimulus"). Ventilation maps showed by means of the z-score how far the response deviates from the signal intensities during the normal air condition. The standard deviation of the lung signal intensities was lowest for the cardiac-triggered series. In the ventilation maps, on the other hand, signal changes were statistically more significant in the respiratory than in the cardiac-triggered series. The average z-scores in the right (left) cranial part of the lung were 12.4 (13.0) and 9.2 (9.7) for respiratory and ECG-triggered acquisitions. We propose to use respiratory triggering as a means to improve the sensitivity of MR ventilation studies.

Ultrafast MRI of the fetus.

During the last decade there has been increasing interest in MRI for the evaluation of ultrasound-detected fetal abnormalities. Motion artefacts previously precluded detailed imaging, but this is now possible using single-shot rapid acquisition sequences. These ultrafast techniques with subsecond images capture 'snap-shot' views of the fetus. By virtue of the infinitely long relaxation time (TR) these images are heavily T2-weighted so that fluid around and within the fetus delineates the anatomy. Currently, fetal MRI has shown to be most beneficial in the investigation of cerebral abnormalities suspected from sonography, and in the detection of subtle associated anomalies. It clearly has a role in the evaluation of complex somatic abnormalities, and is helpful in the evaluation of fetuses prior to surgery. We present a pictorial review of our experience with single-shot fast spin-echo (SSFSE) imaging, demonstrating normal anatomy of the fetal brain and body. In addition we present cerebral and somatic abnormalities to illustrate cases where we have found fetal MRI to be a useful adjunct to sonography.

Right-lobe living related liver transplantation: evaluation of a comprehensive magnetic resonance imaging protocol for assessing potential donors.

The purpose of this study was to determine the practicability and diagnostic accuracy of a magnetic resonance (MR) protocol capable of replacing computed tomography, catheter angiography, and endoscopic retrograde cholangiopancreatography for the presurgical evaluation of potential liver donors before right hepatectomy. MR imaging (MRI) was performed on a 1.5 T scanner using a phased-array torso surface coil for signal reception. The following image sets were collected: axial two-dimensional (2D) T1-weighted fast low angle shot (FLASH), axial 2D T2-weighted half-Fourier acquisition single-shot turbo-spin-echo (HASTE) with fat saturation, coronal MR cholangio-pancreatography (MRCP) based on 2D multisection HASTE and single-section single-shot rapid acquisition with relaxation enhancement (RARE) imaging, dynamic contrast-enhanced three-dimensional (3D) FLASH, and contrast-enhanced T1-weighted FLASH. 3D FLASH data sets were collected before and after an intravenous administration of Multihance (gadobenate dimeglumine, Gd-BOPTA; Bracco, Milano, Italy), 0.2 mmol/kg of body weight. Thirty-eight potential liver donors were assessed by means of MRI. Twenty patients also underwent digital subtraction angiography (DSA). Of these, 16 patients underwent liver harvesting. MR angiography (MRA) data sets correlated with DSA results, and MRCP results correlated with intraoperative findings. Patients were excluded as potential donors based on insufficient liver mass of the left hepatic lobe (n = 5) or presence of hepatic pathological states (n = 9) seen at MRI, such as hemangiomas, focal nodular hyperplasias, or hepatic steatosis. MRCP showed the biliary system to the level of the first hepatic side branch. Dilated ducts were present in 4 patients. MRA depiction of hepatic arterial morphological characteristics correlated with catheter angiography results in all 20 patients: Three left hepatic arteries originating from the left gastric artery, three aberrant right hepatic arteries originating from the superior mesenteric artery, and two aberrant origins of both hepatic arteries and one common hepatic artery originating from the superior mesenteric artery were correctly identified on MRA. Similarly, the portal venous system was fully assessed on MRA. A comprehensive assessment of the hepatic parenchyma, biliary and pancreatic ductal system, and hepatic arterial, portal, and venous systems can be accomplished using the outlined protocol.

MRI and US imaging in fetal anomalies

Purpose: The use of MRI in diagnose fetal abnormalities and the correlation with ultrasound.Methods: Twenty‐five patents in which were diagnosed fetal abnormalities (CNS, thorax and renal) were submitted to MRI. The stage of pregnancy at the time of MR imaging ranged 16–34 weeks gestation. The half‐Fourier single shot rapid acquisition with relaxation enhancement (RARE) technique was used to obtain T2‐weighted images, this sequence has excellent contrast resolution of fetal tissues. It is a single selection acquisition technique limits the artifacts related to maternal and fetal motion.Results: Fetus with CNS, thorax and renal abnormalities were submitted to MRI study. The CNS anomalies were vein of Galen aneurysm, archnoid cyst, Dandy–Walker complex, megacysterna magna, espina bifida. Thorax anomalies were adenomatoid cystic malformation. The renal anomalies were obstructive urophaty, renal displasia. The images of the ultrasound scans and the MRI images were analyzed individually and after compared each other to understand the limits and benefits of each technique.Conclusion: Fast MR imaging techniques provide excellent resolution for imaging the fetal anatomies without the need for maternal or fetal sedation, and should be used as a complementary tool in the diagnosis of fetal anomalies.