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Elspeth H Whitby

Publications and source records attributed to Elspeth H Whitby.

8 recordsLinked to original sources
PubMed2006

Imaging the fetal spine using in utero MR: diagnostic accuracy and impact on management.

BACKGROUND: In-utero MR imaging (iuMR) has entered the clinical arena during the last decade. It is used mainly for imaging fetal brain abnormalities. OBJECTIVE: To report our experience of imaging the fetal spine and spinal cord in fetuses with known or suspected abnormalities diagnosed on US imaging. MATERIALS AND METHODS: Prospective imaging and retrospective analysis of the possible impact on management of 50 consecutive fetuses with spinal abnormalities detected by antenatal US imaging. RESULTS: In 40 (80%) of 50 fetuses, iuMR and US imaging were in complete agreement. In the other 10 fetuses (20%), iuMR provided additional information or changed the diagnosis, including 8 fetuses where the iuMR could find no abnormality and was found to be correct by later follow-up. CONCLUSION: IuMR is useful in fetuses with a suspected spinal abnormality. The clinical impact of iuMR may be numerically less than with brain abnormalities, but is still sufficient to warrant its use, especially if there is any uncertainty about the US imaging, and particularly as a relatively high proportion of diagnoses on US imaging are false-positives.

Female↗
PubMed2006

Simultaneous parallel inclined readout image technique.

Sensitivity-encoded phase undersampling has been combined with simultaneous slice excitation to produce a parallel MRI method with a high volumetric acquisition acceleration factor without the need for auxiliary stepped field coils. Dual-slice excitation was produced by modulating both spin and gradient echo sequences at +/-6 kHz. Frequency aliasing of simultaneously excited slices was prevented by using an additional gradient applied along the slice axis during data acquisition. Data were acquired using a four-channel receiver array and x4 sensitivity encoding on a 1.5 T MR system. The simultaneous parallel inclined readout image technique has been successfully demonstrated in both phantoms and volunteers. A multiplicative image acquisition acceleration factor of up to x8 was achieved. Image SNR and resolution was dependent on the ratio of the readout gradient to the additional slice gradient. A ratio of approximately 2:1 produced acceptable image quality. Use of RF pulses with additional excitation bands should enable the technique to be extended to volumetric acquisition acceleration factors in the range of x16-24 without the SNR limitations of pure partially parallel phase reduction methods.

Algorithms↗
PubMed2006

The OEIS complex: two case reports that illustrate the spectrum of abnormalities and a review of the literature.

We present two cases of OEIS (omphalocele, exstrophy, imperforate anus, spinal defects) complex -MIM 258040 and a review of the literature. Case 1 was a 14-year-old girl who presented at 30 weeks' gestation. An ultrasound examination showed an omphalocele and spina bifida; the bladder was not visualised. She went into spontaneous labour two weeks later and the baby died shortly after birth. A full post-mortem examination was refused, but the mother did agree to an external examination, skin biopsy for fibroblast culture, X rays and MR imaging. The MR imaging showed a pelvic kidney, a large omphalocele containing the other kidney, liver, bowel and a fluid filled structure thought to represent an exstrophy of the bladder (EB). Case 2 was a 30-year-old woman who had an ultrasound examination at 20 weeks' gestation; this showed an omphalocele, but the bladder was not visualised. The pregnancy was subsequently terminated and a post-mortem examination showed a low set umbilical cord associated with a small omphalocele; there was an imperforate anus; a blind ending rectum terminated in the omphalocele. We conclude that these two cases illustrate the variability of the OEIS complex.

Abnormalities, Multiple↗
PubMed2005

Postmortem MR imaging of the fetus: an adjunct or a replacement for conventional autopsy?

Fetal and perinatal autopsy provides essential diagnostic information not only for parents but also for medical audit and clinical trials. The autopsy rate is decreasing throughout the world for numerous reasons. Medical imaging has always been part of the autopsy process, but in the last decade there has been increased interest in imaging as additional to or a replacement for autopsy. This is especially so with the wider availability of magnetic resonance (MR) scanners that are able to provide detailed anatomy of all body structures as well as having the potential to provide information about histopathological patterns of injury. Postmortem MR imaging (MRI) provides similar information to autopsy for gross pathology of most organ systems. It often provides more information in cases of central nervous system abnormalities, but is less accurate for cardiac abnormalities. Targeted, image-guided biopsy may allow histological diagnosis following postmortem MRI.

Autopsy↗
PubMed2004

Ultrafast magnetic resonance imaging of the neonate in a magnetic resonance-compatible incubator with a built-in coil.

BACKGROUND: Magnetic resonance (MR) imaging of the neonate is important clinically, because this group of patients often has complex and multiple problems due to prematurity and developmental abnormalities. MR imaging usually involves moving neonates away from their controlled environment to the scanner. OBJECTIVE: In this study we present the results of our initial experience with an MR-compatible incubator used on a 1.5-T system. METHODS: Seven neonates were imaged at 1.5 T without sedation or anesthesia. Images were obtained by using single-shot fast spin echo, 3-dimensional Fourier transfer gradient echo, and diffusion-weighted sequences. In 4 cases, time-of-flight angiography was performed. RESULTS: All 7 neonates were stable throughout the scan time (10-21 minutes). Experienced observers graded the images for quality, and all were graded excellent or good. In no case was the image quality poor. CONCLUSION: Neonates can be imaged safely by using an MR-compatible incubator and fast image sequences. This method should allow neonates to be imaged by MR in sites at which a dedicated neonatal MR scanner is not available.

Brain↗
PubMed2003

B1AC-MAMBA: B1 array combined with multiple-acquisition micro B0 array parallel magnetic resonance imaging.

The combination of an in-plane B(1) sensitivity encoding (SENSE) technique with a simultaneous multiple-slice B(0) field step technique (multiple-acquisition micro B(0) array (MAMBA)) has produced high scan time reduction factors (R < or = 8). In this study, two slices were acquired simultaneously in combination with x2 and x4 SENSE in-plane encoding using a MAMBA stepped B(0) field coil inside a four-channel phased-array coil system. Experiments were performed on a 1.5 T Infinion system (Philips Medical Systems, Cleveland, OH). The signal-to-noise ratio (SNR) was reduced with higher R factors, as was expected from the reduced number of acquisitions used to create the unaliased images. The combination of SENSE and MAMBA offers great promise for reducing scan times through parallel acquisition while at the same time reducing the number of RF channels required by a factor equal to the number of field steps employed. The B(1) array combined with MAMBA (B(1)AC-MAMBA) technique is applicable when the length of an object is much greater than its diameter, as in scanning limbs or in whole-body screening for disease.

Artifacts↗
PubMed2002

Interleaved pulsed MAMBA: a new parallel slice imaging method.

A method of acquiring slices in parallel is described which uses interleaved sets of pulsed B(0) field coils to generate discrete regions of uniform field within the main magnetic field known as interleaved MAMBA (multiple acquisition micro B(0) array). Simulations of a number of coil designs were performed using the Biot-Savart law. A six-step coil was built and interfaced to a 0.17 T Niche MRI system and the field steps measured using an imaging technique. Measured field steps were in good agreement with the values predicted by simulation. The coil design was then scaled up by a factor of three, interfaced to a 1.5 T whole-body MRI system, and scans of the hands and arms of volunteers were acquired from up to four field steps using standard spin and gradient echo sequences. Images were also acquired simultaneously from two field steps with no frequency encode aliasing and one excitation. The one-dimensional interleaved pulsed MAMBA step field technique shows great promise for enabling many slices to be acquired simultaneously along the axis of the coil for rapid volumetric studies without the need for multiple shot Hadamard encoding. Extension of interleaved coil design to two or three dimensions is feasible, which could provide full spatial coverage combined with ultra-rapid data acquisition.

Echo-Planar Imaging↗