AAPM Task Group Report 325: MRI static magnetic field homogeneity measurement and evaluation procedures - Guidance and resources.

Measurement of static magnetic field (B0) homogeneity is an essential component of routine MRI system evaluation. This report summarizes the work of AAPM Task Group (TG) 325 on vendor-specific methods of B0 homogeneity measurement and evaluation. TG 325 was charged with producing a set of detailed, step-by-step instructions to implement B0 homogeneity measurement methods discussed in the American College of Radiology (ACR) MRI Quality Control Manual using specific makes and models of MRI scanners. The TG produced such instructions for as many approaches as was relevant and practical on six currently available vendor platforms including details of software/tools, settings, phantoms, and other experimental details needed for a reproducible protocol. Because edits to these instructions may need to be made as vendors enter and exit the market and change available tools, interfaces, and access levels over time, the step-by-step instructions are published as a living document on the AAPM website. This summary document provides an introduction to B0 homogeneity testing in MRI and several of the common methods for its measurement and evaluation. A living document on the AAPM website provides vendor-specific step-by-step instructions for performing these tests to facilitate accurate and reproducible B0 homogeneity evaluation on a routine basis.

Convenient Synthesis of Benziodazolone: New Reagents for Direct Esterification of Alcohols and Amidation of Amines.

Hypervalent iodine heterocycles represent one of the important classes of hypervalent iodine reagents with many applications in organic synthesis. This paper reports a simple and convenient synthesis of benziodazolones by the reaction of readily available iodobenzamides with m-chloroperoxybenzoic acid in acetonitrile at room temperature. The structure of one of these new iodine heterocycles was confirmed by X-ray analysis. In combination with PPh3 and pyridine, these benziodazolones can smoothly react with alcohols or amines to produce the corresponding esters or amides of 3-chlorobenzoic acid, respectively. It was found that the novel benziodazolone reagent reacts more efficiently than the analogous benziodoxolone reagent in this esterification.

Sulfonylimino Group Transfer Reaction Using Imino-λ³-iodanes with I2 as Catalyst Under Metal-free Conditions.

A new practical procedure of imination for sulfide has been developed. The treatment of (N-tosylimino)-phenyl-λ³-iodane, PhINTs, with various sulfides in the presence of a catalytic amount of I2 under metal-free conditions affords the corresponding N-tosylsulfilimine compounds with moderate to good yields. This facile transfer procedure of the sulfonylimino group can also be applied to triphenylphosphine to produce the respective iminotriphenylphosphoranes in high yields. According to the reaction mechanism studies, the process of imination from (N-tosylimino)-phenyl-λ³-iodane to sulfide under the conditions may involve radical steps within the reaction mechanism.

Preparation and structure of phenolic aryliodonium salts.

Phenol based aryliodonium salts were prepared by the reaction of [hydroxy(tosyloxy)iodo]arenes with aryl silyl ethers in the presence of trifluoromethanesulfonic acid. Structures of several aryliodonium salts with the hydroxy group in the para-position of the phenyl ring were established by single crystal X-ray crystallography. Under basic conditions, 4-hydroxyphenyl(phenyl)iodonium salts form a dimeric hypervalent iodine(iii) complex, oxyphenyl(phenyl)iodonium ylidic salt, the solid structure of which was confirmed by X-ray crystallography. Phenolic iodonium salts are potentially useful phenol transfer reagents in reactions with various anionic nucleophiles.

Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle.

A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by oxidation of 2-iodo-N,N'-diisopropylisophthalamide with m-chloroperoxybenzoic acid under mild conditions. Single crystal X-ray crystallography of this compound revealed a five-membered bis-heterocyclic structure with two covalent bonds between the iodine atom and the nitrogen atoms. This novel benziodazole is a very stable compound with good solubility in common organic solvents. This compound can be used as an efficient reagent for oxidatively assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate yields.

A Retrospective Database Analysis of Neonatal Morbidities to Evaluate a Composite Endpoint for Use in Preterm Labor Clinical Trials.

Objective To propose and assess a composite endpoint (CE) of neonatal benefit based on neonatal mortality and morbidities by gestational age (GA) for use in preterm labor clinical trials. Study Design A descriptive, retrospective analysis of the Medical University of South Carolina Perinatal Information System database was conducted. Neonatal morbidities were assessed for inclusion in the CE based on clinical significance/risk of childhood neurodevelopmental impairment, frequency, and association with GA in a mother-neonate linked cohort, comprising women with uncomplicated singleton pregnancies delivered at ≥24 weeks' GA. Results Among 17,912 mother-neonate pairs, neonates were at a risk of numerous severe but infrequent morbidities. Clinically important, predominantly rare events were combined into a CE comprising neonatal mortality and morbidities, which decreased in frequency with increasing GA. The highest CE frequency occurred at <31 weeks. High frequency of respiratory distress syndrome, bronchopulmonary dysplasia, and sepsis drove the CE. Median length of hospital stay was longer at all GAs in those with the CE compared with those without. Conclusions Descriptive epidemiological assessment and clinical input were used to develop a CE to measure neonatal benefit, comprising clinically meaningful outcomes. These empirical data and CE allowed trials investigating tocolytics to be sized appropriately.

Preparation, Structure, and Reactivity of Pseudocyclic Benziodoxole Tosylates: New Hypervalent Iodine Oxidants and Electrophiles.

New pseudocyclic benziodoxole tosylates were prepared by the treatment of 1-hydroxybenziodoxolones with p-toluenesulfonic acid or via ligand transfer reaction between PhI(OH)OTs (Koser's reagent) and substituted 2-iodobenzoic acids under mild condition. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.362 Šbetween oxygen and iodine in the iodoxole ring. Pseudocyclic benziodoxole tosylates readily react with various organic substrates as electrophiles or oxidants to afford the corresponding iodonium salts or the products of oxidation. Furthermore, these compounds can be used as efficient recyclable hypervalent iodine reagents. The reduced form of a pseudocyclic benziodoxole tosylate, 2-iodobenzoic acid, can be efficiently recovered from the reaction mixture by a simple acid-base liquid-liquid biphasic procedure.

Chronic lung disease and developmental delay at 2 years of age in children born before 28 weeks' gestation.

INTRODUCTION: Extremely low gestational age newborns (ELGANs) are at increased risk of chronic lung disease (CLD) and of developmental delay. Some studies have suggested that CLD contributes to developmental delay. PATIENTS AND METHODS: We examined data collected prospectively on 915 infants born before the 28th week of gestation in 2002-2004 who were assessed at 24 months of age with the Bayley Scales of Infant Development-2nd Edition or the Vineland Adaptive Behavior Scales. We excluded infants who were not able to walk independently (Gross Motor Function Classification System score < 1) and, therefore, more likely to have functionally important fine motor impairments. We defined CLD as receipt of oxygen at 36 weeks' postmenstrual age and classified infants as either not receiving mechanical ventilation (MV) (CLD without MV) or receiving MV (CLD with MV). RESULTS: Forty-nine percent of ELGANs had CLD; of these, 14% were receiving MV at 36 weeks' postmenstrual age. ELGANs without CLD had the lowest risk of a Mental Developmental Index (MDI) or a Psychomotor Developmental Index (PDI) of <55, followed by ELGANs with CLD not receiving MV, and ELGANs with CLD receiving MV (9%, 12%, and 18% for the MDI and 7%, 10%, and 20% for the PDI, respectively). In time-oriented multivariate models, the risk of an MDI of <55 was associated with the following variables: gestational age of <25 weeks; single mother; late bacteremia; pneumothorax; and necrotizing enterocolitis. The risk of a PDI of <55 was associated with variables such as single mother, a complete course of antenatal corticosteroids, early and persistent pulmonary dysfunction, pulmonary deterioration during the second postnatal week, pneumothorax, and pulmonary interstitial emphysema. CLD, without or with MV, was not associated with the risk of either a low MDI or a low PDI. However, CLD with MV approached, but did not achieve, nominal statistical significance (odds ratio: 1.9 [95% confidence interval: 0.97-3.9]) for the association with a PDI of <55. CONCLUSIONS: Among children without severe gross motor delays, risk factors for CLD account for the association between CLD and developmental delay. Once those factors are considered in time-oriented risk models, CLD does not seem to increase the risk of either a low MDI or a low PDI. However, severe CLD might increase the risk of a low PDI.