Editor’s Choices
Metabolic Abnormalities in Pain-Processing Regions of Patients with Fibromyalgia: A 3T MR Spectroscopy Study • P. Feraco, A. Bacci, Fab. Pedrabissi, L. Passamonti, G. Zampogna, Fed. Pedrabissi, N. Malavolta, and M. Leonardi
As neuroradiologists we see many spine studies for fibromyalgia and wonder about the significance of this condition (is it a real disease?). Here, the authors used MR spectroscopy to assess metabolic alterations in brain regions associated with pain reception (thalami and ventrolateral prefrontal cortex). Using 3T single-voxel MRS, they studied 12 patients and 12 healthy controls and analyzed their data using an LCModel. Glx/Cr and Glu/Cr ratios in the cortex were significantly higher in patients than in controls but no differences were found in the thalami. The authors conclude that these MRS abnormalities support an imbalance in the pain processing areas that underlie fibromyalgia.
Sharp Curvature of Frontal Lobe White Matter Pathways in Children with Autism Spectrum Disorders: Tract-Based Morphometry Analysis • J.-W. Jeong, A.K. Kumar, S.K. Sundaram, H.T. Chugani, and D.C. Chugani
These authors had previously observed abnormalities in the frontal white matter tracts in autistic children and decided to investigate the curvature of these tracts. Thirty-four autistic and 14 control children were imaged and curvature, fractional anisotropy, and axial and radial diffusivity were assessed in 3 frontal lobe fiber tracts. Higher curvatures were found in autistic subjects than in controls. The authors propose that their findings may be the result of thinner axons in these locations. For more on neural phenotyping of autistic brains, see the Jou et al article. It is becoming clear that white matter tract arrangement and neuronal connectivity may be an important substrate of autism.
Structural Neural Phenotype of Autism: Preliminary Evidence from a Diffusion Tensor Imaging Study Using Tract-Based Spatial Statistics • R.J. Jou, N. Mateljevic, M.D. Kaiser, D.R. Sugrue, F.R. Volkmar, and K.A. Pelphrey
The search for an explanation of autism continues and this article supports the hypothesis that aberrations in neuronal connectivity are important defects in this disorder. Fifteen autistic and 8 control boys underwent DTI and fractional anisotropy was used as a measure of fiber tract integrity. FA for each fiber tract affected was correlated with scores of the Social Responsiveness Scale. Autistic patients showed bilateral FA reductions in numerous association, commissural, and projection tracts. Conclusion: DTI shows abnormalities in many long-range fiber tracts suggesting corticocortical connection defects. Because of the type of tracts affected, autism may have a specific neural phenotype.
Fellows’ Journal Club
Lowering the Dose in Head CT Using Adaptive Statistical Iterative Reconstruction • K. Kilic, G. Erbas, M. Guryildirim, M. Arac, E. Ilgit, and B. Coskun
To avoid increased radiation exposure and subsequent long-term risk of cancer, iterative reconstruction is a means of lowering the dose on CT studies. Here, the authors compared head CT scans obtained via standard dose with low-dose (31% less) iterative reconstruction. Signal-to-noise and contrast-to-noise ratios as well as image noise, sharpness, artifacts, and diagnostic acceptability were assessed. Overall these parameters were judged to be better in the standard-dose CT, but those obtained with the lower dose and iterative reconstruction were judged acceptable. Thus, iterative reconstruction appears to be useful in adult head CT examinations. (Editor’s Note: This technique would be ideal in children where radiation dosage is of utmost concern. At my institution we use it for all head and neck studies, but not for temporal bone or paranasal sinus studies as we have found that bone detail may be less than optimal.)
Trainee Misinterpretations on Pediatric Neuroimaging Studies: Classification, Imaging Analysis, and Outcome Assessment • C.V.A. Guimaraes, J.L. Leach, and B.V. Jones
Do trainees make mistakes when interpreting pediatric neuroimaging studies? These authors reviewed trainee reports performed without initial attending physician assessments. They looked at the type of errors and in which type of examinations these occurred and classified the findings according to the severity of discrepancy and its effect on patient management. In nearly 3500 reports there were 143 discrepancies, mostly in CT studies. Only 6 (0.17%) were severe and potentially life-threatening. The most common discrepancies involved fractures and head and neck studies. Discrepancies were higher in interpretations done by third- and fourth-year residents than in those read by fellows.
Oncocytoma: The Vanishing Parotid Mass • N.D. Patel, A. van Zante, D.W. Eisele, H.R. Harnsberger, and C.M. Glastonbury
This is a small retrospective study of a rare lesion, so why include it here? The report describes a previously unknown imaging feature of parotid gland oncocytomas, which appears to be specific for these tumors. All were hypointense with respect to the surrounding gland on precontrast T1 images, but became invisible on postcontrast fat-suppressed T1- and T2-weighted sequences (thus the title of the article). The illustrations are convincing but because this is a retrospective analysis, I wonder how many oncocytomas will show this imaging behavior.
