Reproducibility of arterial spin labeling cerebral blood flow image processing: A report of the ISMRM open science initiative for perfusion imaging (OSIPI)_and the ASL MRI challenge

PURPOSE

Arterial spin labeling (ASL) is a widely used contrast-free MRI method for assessing cerebral blood flow (CBF). Despite the generally adopted ASL acquisition guidelines, there is still wide variability in ASL analysis. We explored this variability through the ISMRM-OSIPI ASL-MRI Challenge, aiming to establish best practices for more reproducible ASL analysis.

METHODS

Eight teams analyzed the challenge data, which included a high-resolution T1-weighted anatomical image and 10 pseudo-continuous ASL datasets simulated using a digital reference object to generate ground-truth CBF values in normal and pathological states. We compared the accuracy of CBF quantification from each team's analysis to the ground truth across all voxels and within predefined brain regions. Reproducibility of CBF across analysis pipelines was assessed using the intra-class correlation coefficient (ICC), limits of agreement (LOA), and replicability of generating similar CBF estimates from different processing approaches.

RESULTS

Absolute errors in CBF estimates compared to ground-truth synthetic data ranged from 18.36 to 48.12 mL/100 g/min. Realistic motion incorporated into three datasets produced the largest absolute error and variability between teams, with the least agreement (ICC and LOA) with ground-truth results. Fifty percent of the submissions were replicated, and one produced three times larger CBF errors (46.59 mL/100 g/min) compared to submitted results.

CONCLUSIONS

Variability in CBF measurements, influenced by differences in image processing, especially to compensate for motion, highlights the significance of standardizing ASL analysis workflows. We provide a recommendation for ASL processing based on top-performing approaches as a step toward ASL standardization.

Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomised controlled trial

Adult users of unilateral Nucleus CI24 cochlear implants with the SPEAK processing strategy were randomised either to receive a second identical implant in the contralateral ear immediately, or to wait 12 months while they acted as controls for late-emerging benefits of the first implant. Twenty four subjects, twelve from each group, completed the study. Receipt of a second implant led to improvements in self-reported abilities in spatial hearing, quality of hearing, and hearing for speech, but to generally non-significant changes in measures of quality of life. Multivariate analyses showed that positive changes in quality of life were associated with improvements in hearing, but were offset by negative changes associated with worsening tinnitus. Even in a best-case scenario, in which no worsening of tinnitus was assumed to occur, the gain in quality of life was too small to achieve an acceptable cost-effectiveness ratio. The most promising strategies for improving the cost-effectiveness of bilateral implantation are to increase effectiveness through enhanced signal processing in binaural processors, and to reduce the cost of implant hardware.

Universality and scaling in the disordering of a smectic liquid crystal

We present experimental and theoretical studies of the effects of quenched disorder on one-dimensional crystal ordering in three dimensions. This fragile smectic liquid crystal layering, the material with the simplest positional order, is also the most easily deformed periodic structure and is, therefore, profoundly affected by disorder, introduced here by confinement in silica aerogel. Theory and experiment combine to characterize this system to an extraordinary degree, their close accord producing a coherent picture: crystal ordering is lost, giving way to extended short-range correlations that exhibit universal structure and scaling, anomalous layer elasticity, and glassy dynamics.

Detection of mutated K12-ras in histologically negative lymph nodes as an indicator of poor prognosis in stage II colorectal cancer

Stage II colorectal carcinoma is characterized by negative lymph node pathology as determined by conventional microscopic examination. These patients generally do not receive adjuvant therapy although 20%-30% will die from metastatic disease. To determine whether K-ras mutations at codon 12 could be used as a sensitive indicator of occult lymph node metastasis in stage II colon carcinoma, a retrospective study was performed using restriction endonuclease-mediated selective polymerase chain reaction (REMS-PCR) amplification. Of 106 colonic tumors analyzed, 46 were identified as positive for a K12-ras mutation in the primary tumor. Multiple lymph node samples from 38 of these 46 patients were examined by a sensitive nested PCR protocol for the presence of a K12-ras mutation. Of these 38 patients, 14 had 1 or more positive lymph nodes by PCR (37%) and 24 were negative for the mutation (63%). Of the 14 patients with a K12-ras mutation detected in lymph nodes, 8 died of the disease within 5 years (57%) compared to only 4 of the 24 patients with ras-negative lymph nodes (17%). The difference in time to death from disease, stratified using K12-ras status of lymph nodes, was statistically significant (P = 0.036; log-rank test). These results suggest K-ras mutation status of lymph nodes in patients with stage II colon cancer might identify a subgroup of patients who are more likely to develop recurrent and/or metastatic disease and benefit from adjuvant therapy. Larger studies are indicated to determine whether detection of K-ras mutation positivity in histologically negative lymph nodes portends a poor prognosis and to determine whether more aggressive use of adjuvant therapy is warranted.

A discotic disguised as a smectic: A hybrid columnar bragg glass

We show that discotics, lying deep in the columnar phase, can exhibit an x-ray scattering pattern which mimics that of a somewhat unusual smectic liquid crystal. This exotic, new glassy phase of columnar liquid crystals, which we call a "hybrid columnar Bragg glass," can be achieved by confining a columnar liquid crystal in an anisotropic random environment of, e.g., strained aerogel. Long-ranged orientational order in this phase makes single-domain x-ray scattering possible, from which a wealth of information could be extracted. We give detailed quantitative predictions for the scattering pattern in addition to exponents characterizing anomalous elasticity of the system.

Schizophrenia: management and care in the community

The move to community care has resulted in many more individuals with severe mental health needs relying on community services. Community facilities did not receive the proceeds from hospital closures and this had led to inadequate provision and facilities for individuals with severe mental health needs. There also appears to have been a lack of effective interventions and skills for dealing with this specific client group. The National Framework Strategy (Department of Health, 1999) for mental health outlines ways to modernize mental health services and aims to ensure that they will be more accessible, more effective and coordinated across health and social care. Over the past decade, there has been a great deal of research examining the effectiveness of psychosocial and family interventions for individuals with psychosis. This article discusses how such interventions could address some of the shortcomings of community care for the severely mentally ill.

Nonequilibrium fluctuations, traveling waves, and instabilities in active membranes

The stability of a flexible fluid membrane containing a distribution of mobile, active proteins (e.g., proton pumps) is shown to depend on the structure and functional asymmetry of the proteins. A stable active membrane is in a nonequilibrium steady state with height fluctuations whose statistical properties are governed by the protein activity. Disturbances are predicted to travel as waves at sufficiently long wavelength, with speed set by the normal velocity of the pumps. The unstable case involves a spontaneous, pump-driven undulation of the membrane, with clumping of the proteins in regions of high activity.

Pregnancy following transfer of ooplasm from cryopreserved-thawed donor oocytes into recipient oocytes

OBJECTIVE

To determine if frozen-thawed donor oocytes could be used to provide cytoplasm for transfer into patients' oocytes to improve subsequent embryonic development.

DESIGN

Prospective evaluation of the procedure in consenting IVF patients.

SETTING

Assisted reproductive technology program.

PATIENT(S)

The study was open to consenting IVF patients (of any age) with a history of poor embryo quality or those couples in which the wife's age was > or = 40 years.

INTERVENTION(S)

Transfer of donor egg cytoplasm from frozen-thawed oocytes into the oocytes of infertile recipients.

MAIN OUTCOME MEASURE(S)

Donor oocyte survival following cryopreservation, fertilization following cytoplasmic transfer into recipient oocytes, embryo quality, and pregnancy outcome.

RESULT(S)

Oocytes collected from four donors were cryopreserved and 61% (28/46) survived the thaw procedure. Cytoplasmic transfer was performed on the eggs of four patients, with fertilization occurring in 70.3% (26/37). Twin pregnancy was established in one patient (35 years of age) with a history of poor embryo quality.

CONCLUSION(S)

Cryopreserved donor oocytes may provide a source of cytoplasm for transfer into recipient oocytes, eliminating the need for cycle synchronization between donor and infertile patient.

Semen quality: is there a paternal effect on pregnancy outcome in in-vitro fertilization/intracytoplasmic sperm injection?

The objective of this study was to investigate the role of the spermatozoon (paternal effects) on implantation and pregnancy outcome in in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Male individuals of three types were analysed: infertile men with oligoasthenoteratozoospermia (OAT), infertile men with normozoospermia and fertile men (donors). Female counterparts were judged to have comparable egg quality within two groups studied, i.e. infertile women with pure mechanical (tubal) infertility and recipients of donor eggs. There were significantly higher differences in implantation and pregnancy rates in groups using donor spermatozoa and donor egg recipients. Analyses of key set groups revealed a trend toward a poorer implantation and pregnancy outcome when comparing OAT versus normozoospermic patients within IVF, but not within ICSI treatments, in couples with tubal infertility. In couples who were recipients of donor eggs, no differences were observed between OAT patients treated by ICSI and normozoospermic patients treated with IVF. No significant differences were observed in miscarriage rates within any groups studied. In conclusion, the poorer results observed in OAT patients undergoing IVF may be secondary to spermatozoal effects due to a high insemination concentration. Overall, there does not seem to be a significant effect of severe male infertility (OAT) on implantation and pregnancy outcome. However, this does not preclude that specific sperm aberrations may exert a negative effect on embryogenesis and therefore on implantation potential following assisted or in-vivo reproduction.

Intracytoplasmic sperm injection: achievement of high pregnancy rates in couples with severe male factor infertility is dependent primarily upon female and not male factors

OBJECTIVE

To determine the efficacy and factors affecting outcome of intracytoplasmic sperm injection (ICSI) in patients with severe male factor infertility.

DESIGN

Prospectively designed clinical trial of patients selected to participate in the study based upon the following inclusion criteria: previous total failed fertilization or unsuitable sperm parameters for conventional IVF.

SETTING

Tertiary care academic center.

PATIENTS

Ninety-two consecutive couples undergoing IVF therapy augmented with ICSI during April through December 1994 were studied.

MAIN OUTCOME MEASURES

Fertilization and ongoing implantation and pregnancy rates (PRs).

RESULTS

A total of 1,163 preovulatory oocytes were manipulated, yielding a diploid fertilization rate of 60.9%; the oocyte damage rate was 13.2%. The transfer rate was 95% with 43.1% of cycles having excess embryos that were cryopreserved. Overall, the clinical and ongoing PRs per transfer were 31.9% and 26.8%, respectively. None of the sperm parameters of the original semen analysis correlated with ICSI outcome. Female age did not affect fertilization results but had a significant impact on PR (< 34 years: 48.9%; 35 to 39 years: 22.9%; > or = 40 years: 5.9% clinical PR per transfer).

CONCLUSIONS

Intracytoplasmic sperm injection offers a new and powerful therapeutic option to treat couples with severe male factor infertility associated with a variety of sperm abnormalities. An adequate female age is a pivotal factor determining a successful outcome.

Prediction of ovarian response to exogenous gonadotropin stimulation: Utilization for collection of primate oocytes for fertilization in vitro

The predictive value of 2 tests for ovarian response to controlled ovarian hyperstimulation in the cynomolgus monkey model was evaluated. The tests utilized were: 1) the cycle Day 3 (Day 1 = onset of menses) FSH value and 2) the acute estradiol (E(2)) response to a GnRH agonists (GnRHa) administered on Day 3. Both tests were performed during the cycle preceding control ovarian hyperstimulation. Subsequently, monkeys (n = 26) were stimulated with Metrodin(T) (Days 2-6, 25IU/d) and Pergonal(T) (Day 7 to hCG administration, 25IU/d). Laparoscopic oocyte retrieval was performed 32 to 34 after hCG administration. Analysis of the data revealed that Day 3 FSH values could not predict whether an animal would respond well to control ovarian hyperstimulation in a subsequent cycle (P = 0.77). However, the E(2) change 24 h post-GnRHa administration was significantly greater for animals responding well to control ovarian hyperstimulation compared with the animals deleted after 6 d of stimulation (P = 0.042). The mean change in E(2) levels in animals taken to aspiration was 97.8 pg/ml compared with only 21.6 pg/ml for the deleted animals. This differential response of E(2) production after GnRHa treatment was used to correctly identify (by discriminant analysis) 78% of the animals subsequently deleted for poor response. Thus, the increase in serum E(2) level after GnRHa, but not the basal FSH level, was found to be predictive of ovarian response to stimulation in the cynomolgus monkey.

High doses of gonadotropins have no detrimental effect on in vitro fertilization outcome in normal responders

OBJECTIVE

To examine the effect of high doses of gonadotropins on IVF outcome in normal (intermediate) responders.

DESIGN

Retrospective analysis of patients undergoing IVF therapy from 1990 to 1994 at our institution.

SETTING

Academic tertiary center.

PATIENTS

A homogeneous group of women that consisted of intermediate responders examined in their initial attempt and who received differing amounts of gonadotropins were examined.

INTERVENTIONS

All patients were stimulated using a combination of a GnRH-agonist and FSH and hMG and were allocated into two groups, based on the amount of gonadotropin administered initially (four or six ampules).

MAIN OUTCOME MEASURES

Implantation and pregnancy (clinical and ongoing) rates were compared.

RESULTS

There were no significant differences between patients receiving high doses versus those patients receiving lower doses of gonadotropins with regard to implantation and pregnancy rates.

CONCLUSIONS

We conclude that high doses of gonadotropins have no detrimental effect on IVF outcome in normal (intermediate) responders.

Prediction of fertilization in vitro with human gametes: is there a litmus test?

OBJECTIVES

The objectives of this study were as follows: (1) to evaluate the relationships between sperm concentration, morphologic pattern, motion parameters, and sperm-zona pellucida binding capacity and (2) to assess their ability to predict fertilization outcome under in vitro fertilization conditions.

STUDY DESIGN

Semen samples from 44 infertile men were prospectively evaluated for density, morphologic pattern (strict criteria), computerized motion parameters (motility, velocity, and linearity), and hemizona assay (outcome expressed as hemizona assay index), and results were correlated with fertilization outcomes of preovulatory oocytes during in vitro fertilization.

RESULTS

Of all sperm parameters, morphologic pattern was the best predictor of the ability of the sperm to bind to the zona pellucida. Hemizona assay index was the best predictor of fertilization rate. Stepwise regression analysis provided a model of hemizona assay index plus motility with highest predictability (R2 = 53.4%).

CONCLUSIONS

(1) The influence of sperm morphologic pattern as a prognosticator of fertilization outcome is established in major part as a determinant of sperm binding ability to the zona pellucida; (2) the hemizona assay provides a robust index that is highly predictive of the potential of human gametes to achieve fertilization and highlights its use in infertility and contraception testing.

Strategies in the treatment of major tissue loss and gangrene: results of 100 consecutive vascular reconstructions

To determine the features of a successful clinical strategy, we analyzed the results of 100 consecutive lower extremity vascular reconstructions performed exclusively for tissue loss and gangrene of the legs and feet. Eighty patients underwent 100 procedures on 80 limbs. Follow-up was 95% complete (every six months, mean 2.2 years). Forty inflow procedures to the femoral artery were performed with 13 simultaneous infrainguinal bypasses. Sixty bypasses were performed from the femoral artery to the popliteal (25) or tibial arteries (35). Sixty-eight percent of the identified ulcerations healed, and limb salvage was achieved in 70% of patients by life-table analysis. The cumulative patency for all reconstructions was 48% (five years), for tibial bypasses 60% (four years). Femoropopliteal bypasses had the poorest patency and healing rates (less than 40%), while combined inflow-outflow procedures and femorotibial bypasses had the highest rates of healing (77%, 66%). There were two operative deaths, three graft infections, seven wound infections, and 12 acute graft thromboses. Vascular reconstructions for extensive tissue loss or gangrene can be performed with a morbidity and mortality comparable to procedures performed for less severe disease with a high rate of limb salvage. The long term success of surgical therapy depends primarily on the most direct revascularization of ischemic, infected tissues, using autologous conduits whenever possible.

Comparison of self-administered and rater-administered methods of assessing levels of severity of depression in elderly patients

Eighty consecutive attenders (M age = 75 years) in a primary care group practice associated with a teaching hospital in New York were assessed for depression using a self-administered questionnaire, the Zung Self-Rating Depression Scale (SDS), and a rater-administered interview, the Short-CARE. The sample was 75% female and 85% black or Hispanic. The response rate of completed interviews was 65% for the Zung SDS and 100% for the Short-CARE. Among the reasons indicated by subjects for not filling out the Zung SDS were visual problems (n = 13, 28%), illiteracy (n = 4, 9%), and lack of motivation/wanted it read to them (n = 16, 34%). Additionally, using the Primary Care Physicians' Questionnaire (PCPQ), results from the Short-CARE and the Zung SDS were compared to primary care physicians' judgments regarding the presence of depression in these patients. The convergent validity coefficient for the Zung SDS with the PCPQ was .65 (kappa = .29); the comparable coefficients for the PCPQ and the Short-CARE Depression Scale were .73 and .46 respectively.