Skeletal muscle ultrasonography: Visual versus quantitative evaluation

In this study, we compared the sensitivity and specificity of visual versus quantitative evaluation of skeletal muscle ultrasound in children suspected of having a neuromuscular disorder (NMD). Ultrasonography (US) scans of four muscles (biceps brachii, forearm flexors, quadriceps femoris, anterior tibial muscle) were made in 76 children. All images were visually evaluated using the Heckmatt criteria and quantitatively evaluated with computer-assisted grey-scale analysis of muscle echo intensity. Visual evaluation could achieve a sensitivity up to 71%, with a specificity of 92%. With quantification, a sensitivity of 87% accompanied by a specificity of 67% was found, but other diagnostic values could be achieved, depending on the cut-off point. Quantification resulted in a higher interobserver agreement (kappa 0.86) compared with visual evaluation (kappa 0.53). We conclude that quantification of echo intensity is a more objective and accurate method. Because it can achieve higher sensitivities, it is better-suited for the screening task in the diagnostic phase of children with a NMD.     

Neonatal thymectomy reveals differentiation and plasticity within human naive T cells

The generation of naive T cells is dependent on thymic output, but in adults, the naive T cell pool is primarily maintained by peripheral proliferation. Naive T cells have long been regarded as relatively quiescent cells; however, it was recently shown that IL-8 production is a signatory effector function of naive T cells, at least in newborns. How this functional signature relates to naive T cell dynamics and aging is unknown. Using a cohort of children and adolescents who underwent neonatal thymectomy, we demonstrate that the naive CD4⁺ T cell compartment in healthy humans is functionally heterogeneous and that this functional diversity is lost after neonatal thymectomy. Thymic tissue regeneration later in life resulted in functional restoration of the naive T cell compartment, implicating the thymus as having functional regenerative capacity. Together, these data shed further light on functional differentiation within the naive T cell compartment and the importance of the thymus in human naive T cell homeostasis and premature aging. In addition, these results affect and alter our current understanding on the identification of truly naive T cells and recent thymic emigrants.     

MRI for staging lymphoma: Whole‐body or less?

Purpose:

To assess whether whole‐body MRI detects more clinically relevant lesions (i.e., leading to a change in Ann Arbor stage) than an MRI protocol that only includes the head/neck and trunk (i.e., from cranial vertex to groin, excluding the arms) in patients with lymphoma.

Materials and Methods:

One hundred consecutive patients with newly diagnosed lymphoma prospectively underwent T1‐weighted and T2‐weighted short inversion time inversion recovery whole‐body MRI. The number of lymphomatous sites at MRI with a field of view (FOV) limited to the head/neck and trunk, and the additional number of lymphomatous sites at whole‐body MRI and their influence on Ann Arbor stage were determined.

Results:

At MRI with a FOV limited to the head/neck and trunk, 507 sites were classified as lymphomatous. At whole‐body MRI, 7 additional sites outside the head/neck and trunk in 7 patients (7.0%; 95% confidence interval: 3.4–13.8%) were classified as lymphomatous, but Ann Arbor stage never changed.

Conclusion:

Whole‐body MRI did not detect any clinically relevant lesions outside the FOV of an MRI protocol that only includes the head/neck and trunk. Therefore, it may be sufficient to only include the head/neck and trunk when using MRI for staging lymphoma. J. Magn. Reson. Imaging 2011;33:1144–1150. © 2011 Wiley‐Liss, Inc.     

Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS): features and potential applications in oncology

Diffusion-weighted magnetic resonance imaging (DWI) provides functional information and can be used for the detection and characterization of pathologic processes, including malignant tumors. The recently introduced concept of "diffusion-weighted whole-body imaging with background body signal suppression" (DWIBS) now allows acquisition of volumetric diffusion-weighted images of the entire body. This new concept has unique features different from conventional DWI and may play an important role in whole-body oncological imaging. This review describes and illustrates the basics of DWI, the features of DWIBS, and its potential applications in oncology.     

Effects of hyperprolactinemia on the accessory sexual organs of the male rat

The growth-promoting effect of prolactin on the ventral prostate lobe, the anterior prostate lobe (or coagulating gland), and seminal vesicles has been studied before, during and after puberty in rats up to 5 months of age. Pituitaries from female rats were grafted under the renal capsule of 23-26-day-old male rats. Within 1/2 month substantial (five- to ten-fold) hyperprolactinemia occurred followed by a gradual decline; levels were still high 4 months after grafting. A statistically significant increase in the weight of the seminal vesicles and the ventral and anterior prostate lobes was observed 1 month after implantation. This effect was only maintained for the seminal vesicles during the next 3 months. Hyperprolactinemia did not influence testosterone metabolism. In the ventral prostate lobe, 1 month after grafting, the nuclear androgen receptor content increased, whereas the cytosolic androgen receptor content decreased. These results suggest that the growth-promoting effect of prolactin, on the ventral prostate lobe of the rat, is brought about by an increased translocation of the androgen receptor.     

Hepatobiliary and pancreatic imaging in children—techniques and an overview of non-neoplastic disease entities

Imaging plays a major role in the diagnostic work-up of children with hepatobiliary or pancreatic diseases. It consists mainly of US, CT and MRI, with US and MRI being the preferred imaging modalities because of the lack of ionizing radiation. In this review the technique of US, CT and MRI in children will be addressed, followed by a comprehensive overview of the imaging characteristics of several hepatobiliary and pancreatic disease entities most common in the paediatric age group.