Comparison of a 28-channel receive array coil and quadrature volume coil for morphologic imaging and T2 mapping of knee cartilage at 7T

Purpose:

To compare a new birdcage‐transmit, 28‐channel receive array (28‐Ch) coil and a quadrature volume coil for 7T morphologic MRI and T2 mapping of knee cartilage.

Materials and Methods:

The right knees of 10 healthy subjects were imaged on a 7T whole body magnetic resonance (MR) scanner using both coils. 3D fast low‐angle shot (3D‐FLASH) and multiecho spin‐echo (MESE) sequences were implemented. Cartilage signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), thickness, and T2 values were assessed.

Results:

SNR/CNR was 17%–400% greater for the 28‐Ch compared to the quadrature coil (P ≤ 0.005). Bland–Altman plots show mean differences between measurements of tibial/femoral cartilage thickness and T2 values obtained with each coil to be small (?0.002 ± 0.009 cm / 0.003 ± 0.011 cm) and large (?6.8 ± 6.7 msec/?8.2 ± 9.7 msec), respectively. For the 28‐Ch coil, when parallel imaging with acceleration factors (AF) 2, 3, and 4 was performed SNR retained was: 62%–69%, 51%–55%, and 39%–45%.

Conclusion:

A 28‐Ch knee coil provides increased SNR/CNR for 7T cartilage morphologic imaging and T2 mapping. Coils should be switched with caution during clinical studies because T2 values may differ. The greater SNR of the 28‐Ch coil could be used to perform parallel imaging with AF2 and obtain similar SNR as the quadrature coil. J. Magn. Reson. Imaging 2012;441‐448. © 2011 Wiley Periodicals, Inc.

     

Hepatitis B among University Population: Prevalence,Associated Risk Factors,Knowledge Assessment,and Treatment Management

Background: Very few studies have been reported on hepatitis B in the State of Azad Jammu and Kashmir, Pakistan, and none of them are specific to the prevalence and causes of hepatitis B spread among educational institutes. This study aimed to estimate the prevalence of hepatitis B infection and its associated risk factors among the University of AJ and K population. Methods: An observational, cross-sectional, and analytical study was conducted with 7015 students and employees. Hepatitis B was detected by rapid immunochromatographic tests (ICTs), enzyme-linked immunosorbent assay (ELISA), and real-time quantitative PCR. A questionnaire and interview method was used to assess the disease knowledge and associated risk factors with hepatitis B through Chi-square, Fisher’s exact test, and paired t-test. Results: Of the participants, 150 (2.13%) were found positive for the hepatitis B surface antigen (57.3% male and 42.7% female). Only 0.3% participants were found fully vaccinated against the hepatitis B virus. Among ethnic groups, the Syed tribe was found more prevalent for hepatitis B infection (40.6%), while use of contaminated mourning blades (95% CI: p = 0.0001) was found as an overlooked risk factor. Hepatitis preventive awareness sessions were found to be very significant (p = 0.0001). Conclusions: The study showed that an overlooked risk factor is playing a key role in the spread of HBV in a tribe living worldwide, which must be addressed globally to eradicate hepatitis B. In Pakistan, a country-wide annual HBV vaccination program should be launched to control hepatitis B.     

Prolonged inhibition of the flexor reflex by probing the cervix uteri in the cat

In decerebrate or spinal cats, sustained mechanical stimulation of the cervix uteri inhibited the flexor reflex elicited by electrical stimulation of the foot pad during the probing period (160 s). After probing, 3–15 min were required for reflex recovery. No additional inhibition was produced if probing was repeated before recovery, but instead the reflex was facilitated. When probing was applied 5–10 min after reflex recovery the reflex was again abolished. The recovery, however, occurred earlier and was followed by facilitation. Probing the cervix with single mechanical pulses inhibited transiently (140–200 ms) the short latency reflex components, but the components with longer latencies are unaffected or facilitated. Distension of the vaginal wall with balloon also inhibited the flexor reflex, but a transient, mild facilitation appeared several seconds after the distension. In general, whenever the inhibition decreases, the facilitation predominates. Our findings suggest that cervical probing or vaginal distension triggers both a long-lasting inhibition and a concomitant facilitation in different intraspinal flexor reflex pathways.     

Noninvasive magnetic resonance imaging of transport and interstitial fluid pressure in ectopic human lung tumors

Tumor response to blood borne drugs is critically dependent on the efficiency of vascular delivery and transcapillary transfer. However, increased tumor interstitial fluid pressure (IFP) forms a barrier to transcapillary transfer, leading to resistance to drug delivery. We present here a new, noninvasive method which estimates IFP and its spatial distribution in vivo using contrast-enhanced magnetic resonance imaging (MRI). This method was tested in ectopic human non-small-cell lung cancer which exhibited a high IFP of approximately 28 mm Hg and, for comparison, in orthotopic MCF7 human breast tumors which exhibited a lower IFP of approximately 14 mm Hg, both implanted in nude mice. The MRI protocol consisted of slow infusion of the contrast agent [gadolinium-diethylenetriaminepentaacetic acid (GdDTPA)] into the blood for approximately 2 hours, sequential acquisition of images before and during the infusion, and measurements of T1 relaxation rates before infusion and after blood and tumor GdDTPA concentration reached a steady state. Image analysis yielded parametric images of steady-state tissue GdDTPA concentration with high values of this concentration outside the tumor boundaries, approximately 1 mmol/L, declining in the tumor periphery to approximately 0.5 mmol/L, and then steeply decreasing to low or null values. The distribution of steady-state tissue GdDTPA concentration reflected the distribution of IFP, showing an increase from the rim inward, with a high IFP plateau inside the tumor. The changes outside the borders of the tumors with high IFP were indicative of convective transport through the interstitium. This work presents a noninvasive method for assessing the spatial distribution of tumor IFP and mapping barriers to drug delivery and transport.     

Immune precipitin reactions between an anti-human myoglobin antiserum and several purified primate myoglobins

1. Several primate myoglobins cross-react with a rabbit antiserum to human myoglobin.

2. No immunoelectrophoretic differences are detectable among these reactions.

3. Differences can be detected in agar gel double diffusion reactions, cross-absorption, and quantitative precipitin reactions.

4. Myoglobins of man and the apes (Group I Hominoidae) precipitate the maximum amount of protein from the anti-human myoglobin serum, give reactions of coalescence with each other in gels, and totally abolish reactivity of the antiserum with any primate myoglobin after absorption.

5. Myoglobins of baboons and macaques (Group II Cercopithecoidae) precipitate an average of approximately three-fourths as much protein from the antiserum as myoglobin of man and apes, and give reactions of coalescence with each other in gels but additional spurs are formed by Group I myoglobins. After absorption with myoglobins of baboons and macaques, antibody reactive with Group I myoglobins is left in the serum.

6. Myoglobin of the squirrel monkey (Group III Ceboidae) precipitates approximately one-third as much protein from the antiserum as myoglobins from man and apes, and, when used for absorption of the rabbit antiserum, leaves behind antibody capable of reacting with Groups I and II myoglobins.

7. A hypothesis proposing similarity of structure of myoglobin molecules between members of each group, and differences of from one to three sites between members of different groups, is suggested.

     

Two closely related strains associated with pertussis resurgence in Israel

Eighty-two isolates of Bordetella pertussis analyzed by pulsed-field gel electrophoresis from the epidemic years, 2007 to 2008, revealed 4 strains with 2 closely related isolates accounting for 95% of the circulating strains. The most common Israeli strain has the same pulsed-field gel electrophoresis cluster as the dominant European BpSR11 strain (pulsed-field gel electrophoresis cluster IVβ) identified in the 1999 to 2004 EU Pertstrain II project.