Sarah Ellestad

Medical and surgical treatment of placenta percreta to optimize bladder preservation.

BACKGROUND: Placenta percreta is associated with significant morbidity and mortality. Interventions are dictated by hemodynamic stability, desire to retain future fertility, and efforts to reduce surgical morbidity at time of delivery. CASES: Two cases of antenatally diagnosed placenta percreta with bladder invasion are presented. Conservative management was used, including endovascular interventions, leaving the placenta in situ, methotrexate, and delayed hysterectomy. Postoperative outcomes were acceptable, with no significant hemorrhagic complications or need for extensive bladder reconstruction. CONCLUSION: Antenatal diagnosis of placenta percreta with bladder invasion is essential in the multidisciplinary management of this potentially catastrophic condition. A comprehensive approach including delayed hysterectomy after medical management resulted in an excellent clinical outcome.

Severe factor V deficiency presenting with intracranial haemorrhage during gestation.

Summary.  We present a case of intracranial haemorrhage detected by ultrasound at 36 weeks gestation in a foetus who was ultimately diagnosed with severe factor V deficiency. An abnormality of the foetal heart rate, auscultated at a routine antenatal visit, prompted an investigation that led to an ultrasound examination and detection of an intracranial haemorrhage and low amniotic fluid volume. An intrauterine foetal demise was averted. The clinical scenario in this case raises the issue of how often a stillbirth with intracranial haemorrhage may result from unrecognized factor deficiency.

Prenatal diagnosis of a trauma-related fetal epidural hematoma

BACKGROUND: Prenatal diagnosis of fetal intracranial hemorrhage has important etiologic, management, and prognostic implications. Ultrasonography and magnetic resonance imaging (MRI) have been used to identify and evaluate this condition. We present the first reported case of epidural hematoma diagnosed prenatally. CASE: A 25-year-old para 3 was referred for evaluation of a suspected fetal intracranial abnormality following an alleged assault. Ultrasonography and MRI were used to diagnose an epidural hematoma prenatally. The fetus subsequently died in utero. Autopsy confirmed the presence of an epidural hematoma. CONCLUSION: Ultrasonography and MRI were useful in diagnosing a fetal epidural hematoma. Unfortunately, no known effective in utero therapy exists for this rare problem.

In Vivo Application of Short-Lag Spatial Coherence and Harmonic Spatial Coherence Imaging in Fetal Ultrasound

Fetal scanning is one of the most common applications of ultrasound imaging and serves as a source of vital information about maternal and fetal health. Visualization of clinically relevant structures, however, can be severely compromised in difficult-to-image patients due to poor resolution and the presence of high levels of acoustical noise or clutter. We have developed novel coherence-based beamforming methods called Short-Lag Spatial Coherence (SLSC) imaging and Harmonic Spatial Coherence imaging (HSCI), and applied them to suppress the effects of clutter in fetal imaging. This method is used to create images of the spatial coherence of the backscattered ultrasound as opposed to images of echo magnitude. We present the results of a patient study to assess the benefits of coherence-based beamforming in the context of first trimester fetal exams. Matched fundamental B-mode, SLSC, harmonic B-mode, and HSCI images were generated using raw radio frequency data collected on 11 volunteers in the first trimester of pregnancy. The images were compared for qualitative differences in image texture and target conspicuity as well as using quantitative imaging metrics such as signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast. SLSC and HSCI showed statistically significant improvements across all imaging metrics compared with B-mode and harmonic B-mode, respectively. These improvements were greatest for poor quality B-mode images where contrast of anechoic targets was improved from 15 dB in fundamental B-mode to 27 dB in SLSC and 17 dB in harmonic B-mode to 30 dB in HSCI. CNR improved from 1.4 to 2.5 in the fundamental images and 1.4 to 3.1 in the harmonic case. These results exhibit the potential of coherence-based beamforming to improve image quality and target detectability, especially in high noise environments.

First trimester screening.

Screening for aneuploidy has traditionally been reserved for women of advanced maternal age. More recent advances in serum screening and ultrasound technology have allowed women of all ages to be offered screening in the second and even first trimester. These methods and their effectiveness are discussed.

In vivo performance evaluation of short-lag spatial coherence and harmonic spatial coherence imaging in fetal ultrasound

Ultrasonography is the primary imaging modality used for diagnostic assessment of fetal and maternal health during pregnancy. However, a large proportion of fetal ultrasound exams suffer from inadequate or lack of visualization of clinically relevant structures due to acoustical noise or clutter. These undesirable effects are even more pronounced in overweight and obese mothers. In previous work our group has introduced short-lag spatial coherence (SLSC) and harmonic spatial coherence imaging (HSCI) as methods for clutter reduction. These have been shown to be successful in improving image contrast and border delineation in both simulations and in vivo experiments on liver and cardiac imaging. We extend the application of these techniques to fetal ultrasound imaging. We collected individual channel RF data on 11 volunteers in their first trimester of pregnancy. The amount of intrinsic clutter varied across the volunteers. These data sets were used to generate matched fundamental B-mode, SLSC, harmonic B-mode, and HSCI images. These images were compared qualitatively by assessing image texture and target detectability and quantitatively using SNR, CNR, and contrast. SLSC and HSCI images showed significant improvements across all imaging metrics compared to B-mode and harmonic B-mode, respectively. The improvements in clutter suppression and improved conspicuity of target structures were greatest for poor quality B-mode images. Clutter levels in these images, measured in a region of amniotic fluid compared to a region of uniform speckle, were measured to be 15 dB for B-mode versus 27 dB for SLSC, and 17 dB for harmonic B-mode versus 30 dB for HSCI. CNR for the same set of images improved from 1.4 to 2.5 for B-mode to SLSC and from 1.4 to 3.1 for harmonic B-mode to HSCI.

Clinical Utility of Fetal Short-Lag Spatial Coherence Imaging

In this study, we evaluate the clinical utility of fetal short-lag spatial coherence (SLSC) imaging. Previous work has documented significant improvements in image quality with fetal SLSC imaging as quantified by measurements of contrast and contrast-to-noise ratio (CNR). The objective of this study was to examine whether this improved technical efficacy is indicative of the clinical utility of SLSC imaging. Eighteen healthy volunteers in their first and second trimesters of pregnancy were scanned using a modified Siemens SC2000 clinical scanner. Raw channel data were acquired for routinely examined fetal organs and used to generate fully matched raw and post-processed harmonic B-mode and SLSC image sequences, which were subsequently optimized for dynamic range and other imaging parameters by a blinded sonographer. Optimized videos were reviewed in matched B-mode and SLSC pairs by three blinded clinicians who scored each video based on overall quality, target conspicuity and border definition. SLSC imaging was highly favored over conventional imaging with SLSC scoring equal to (28.2 ± 10.5%) or higher than (63.9 ± 12.9%) B-mode for video pairs across all examined structures and processing conditions. Multivariate modeling revealed that SLSC imaging is a significant predictor of improved image quality with p ≤ 0.002. Expert-user scores for image quality support the application of SLSC in fetal ultrasound imaging.

Translation of fetal short-lag spatial coherence (SLSC) imaging into clinical practice: A pilot study

Fetal short-lag spatial coherence (SLSC) imaging has demonstrated 64–85% increases in CNR and 17–29% increases in contrast relative to conventional B-mode imaging. However, despite its proven technical efficacy, the viability of fetal SLSC in the clinical setting remains unknown. The aims of this study were: 1) To demonstrate the feasibility of real-time SLSC imaging on existing hardware and 2) to evaluate expert-user preference between SLSC and B-mode within the clinical workflow.