Evaluation of Thick-Slab Overlapping MIP Images of Contrast-Enhanced 3D T1-Weighted CUBE for Detection of Intracranial Metastases: A Pilot Study for Comparison of Lesion Detection, Interpretation Time, and Sensitivity with Nonoverlapping CUBE MIP, CUBE, and Inversion-Recovery-Prepared Fast-Spoiled Gradient Recalled Brain Volume.

BACKGROUND AND PURPOSE: Early and accurate identification of cerebral metastases is important for prognostication and treatment planning although this process is often time consuming and labor intensive, especially with the hundreds of images associated with 3D volumetric imaging. This study aimed to evaluate the benefits of thick-slab overlapping MIPs constructed from contrast-enhanced T1-weighted CUBE (overlapping CUBE MIP) for the detection of brain metastases in comparison with traditional CUBE and inversion-recovery prepared fast-spoiled gradient recalled brain volume (IR-FSPGR-BRAVO) and nonoverlapping CUBE MIP. MATERIALS AND METHODS: A retrospective review of 48 patients with cerebral metastases was performed at our institution from June 2016 to October 2017. Brain MRIs, which were acquired on multiple 3T scanners, included gadolinium-enhanced T1-weighted IR-FSPGR-BRAVO and CUBE, with subsequent generation of nonoverlapping CUBE MIP and overlapping CUBE MIP. Two blinded radiologists identified the total number and location of metastases on each image type. The Cohen κ was used to determine interrater agreement. Sensitivity, interpretation time, and lesion contrast-to-noise ratio were assessed. RESULTS: Interrater agreement for identification of metastases was fair-to-moderate for all image types (κ = 0.222-0.598). The total number of metastases identified was not significantly different across the image types. Interpretation time for CUBE MIPs was significantly shorter than for CUBE and IR-FSPGR-BRAVO, saving at least 50 seconds per case on average (P < .001). The mean lesion contrast-to-noise ratio for both CUBE MIPs was higher than for IR-FSPGR-BRAVO. The mean contrast-to-noise ratio for small lesions (<4 mm) was lower for nonoverlapping CUBE MIP (1.55) than for overlapping CUBE MIP (2.35). For both readers, the sensitivity for lesion detection was high for all image types but highest for overlapping CUBE MIP and CUBE (0.93-0.97). CONCLUSIONS: This study suggests that the use of overlapping CUBE MIP or nonoverlapping CUBE MIP for the detection of brain metastases can reduce interpretation time without sacrificing sensitivity, though the contrast-to-noise ratio of lesions is highest for overlapping CUBE MIP.

Physical and geometrical parameters controlling measurements of radon emanation and exhalation from soil.

The influence of physical and geometrical parameters, such as grain size, volume of the emanation container and mass of the sample, on the emanation coefficient and exhalation rates of radon (with and without consideration of back diffusion effect and effective volume of the emanation container) released from soil have been investigated. Moreover, a method for assessing the flux of radon migrate through soil layers was proposed. This method is based on measurement of the cumulative radon concentration transmitted through five layers of soil. The transmission factor results from the decay of 222Rn over a period of 60 day required for it to migrate through these layers was also determined. The soil samples were collected from Al-Marj city located in northeastern Libya. Radon measurements were carried out by using a closed emanation container based on CR-39 nuclear track detectors (NTDs). The results showed that the radon emanation coefficient clearly increases with grain size, container volume and sample mass. The exhalation rates also increase with grain size and sample mass, but the container volume parameter shows an opposite trend. The radon flux and its transmission factor are significantly decreased throughout that uniform soil when the increase in soil depth retarded exhalation. This study shows that various physical and geometrical parameters were demonstrated to be greatly affected on the emanation coefficient and exhalation rates of radon released from soil.

Radon exhalation from Libyan soil samples measured with the SSNTD technique.

Radon concentrations in soil samples collected from the cities of Benghazi and Al-Marj, located in northeastern Libya, were measured using the sealed-can technique based on the CR-39 SSNTDs. Mass and areal radon exhalation rates, radium content and radon concentration contribute to indoor radon, and annual effective doses were determined. The results indicate mostly normal rates, but there were some higher levels of radon concentration and emanation in samples collected from Al-Marj and one sample from Benghazi.

Antimicrobial resistance and R factors in Salmonella isolated from humans and animals in Georgia and South Carolina.

Three hundred and five strains of Salmonella isolated from humans and 152 strains isolated from animals in Georgia and South Carolina during 1973 were examined for resistance to 14 antimicrobial agents. S typhimurium was the most frequently isolated serotype (30% of human isolates and 13% of animal isolates). The overall incidence of antimicrobial resistance was 16% in human starins and 21% in animal strains. The most commonly found resistance were to streptomycin (11% in human strains and 16% in animal strains) and tetracycline (10% in both human and animal isolates). A higher prevalence of resistance to streptomycin, spectinomycin, and nitrofurantoin, which are currently used primarily in veterinary medicine, was found in animal Salmonella. Conversely, resistance to ampicillin, cephalothin, and kanamycin, which are used mainly in human medicine, was found more frequently in human Salmonella. No resistance to nalidixic acid, gentamicin, tobramycin, rifampin, or trimethoprim was detected. Sixty-five percent of resistant strains from humans and 60% of resistant strains from animals transferred their resistance patterns partially or in toto.