Single enhancing brain lesions (SELs), mostly as a result of neurocysticercosis or tuberculosis, are a common cause of seizures. Ten patients with SELs caused by neurocysticercosis (n=6) or tuberculosis (n=4) were examined by proton magnetic resonance spectroscopy. Tuberculomas had a high peak of lipids, more choline, and less N-acetylaspartate and creatine. The choline/creatine ratio was greater than 1 in all tuberculomas but in none of the cysticerci. Magnetic resonance spectroscopy differentiates SELs caused by cysticercosis or tuberculosis and may avoid brain biopsies or unnecessary antituberculosis treatments.

A singlet peak at ∼3.8 ppm is present in the majority of tuberculomas and absent in most malignant tumors, potentially a marker to differentiate these lesions. The assignment of the peak is difficult from our analysis; however, guanidinoacetate (Gua) is a possibility. Higher Cho/Cr and mI/Cr ratios should favor malignant lesions over tuberculomas. The presence of lipids and Glx is non-specific.

BACKGROUND AND PURPOSE: Noncontrast CT of the head is the initial imaging test for traumatic brain injury, stroke, or suspected nonaccidental trauma. Low-dose head CT protocols using filtered back-projection are susceptible to increased noise and decreased image quality. Iterative reconstruction noise suppression allows the use of lower-dose techniques with maintained image quality. We review our experience with children undergoing emergency head CT examinations reconstructed using knowledge-based iterative model reconstruction versus standard filtered back-projection, comparing reconstruction times, radiation dose, and objective and subjective image quality. MATERIALS AND METHODS:This was a retrospective study comparing 173 children scanned using standard age-based noncontrast head CT protocols reconstructed with filtered back-projection with 190 children scanned using low-dose protocols reconstructed with iterative model reconstruction. ROIs placed on the frontal white matter and thalamus yielded signal-to-noise and contrast-to-noise ratios. Volume CT dose index and study reconstruction times were recorded. Random subgroups of patients were selected for subjective image-quality review. RESULTS:The volume CT dose index was significantly reduced in studies reconstructed with iterative model reconstruction compared with filtered back-projection, (mean, 24.4 Ϯ 3.1 mGy versus 31.1 Ϯ 6.0 mGy, P Ͻ .001), while the SNR and contrast-to-noise ratios improved 2-fold (P Ͻ .001). Radiologists graded iterative model reconstruction images as superior to filtered back-projection images for gray-white matter differentiation and anatomic detail (P Ͻ .001). The average reconstruction time of the filtered back-projection studies was 101 seconds, and with iterative model reconstruction, it was 147 seconds (P Ͻ .001), without a practical effect on work flow. CONCLUSIONS:In children referred for emergency noncontrast head CT, optimized low-dose protocols with iterative model reconstruction allowed us to significantly reduce the relative dose, on average, 22% compared with filtered back-projection, with significantly improved objective and subjective image quality. ABBREVIATIONS:ASIR ϭ adaptive statistical iterative reconstruction; CNR ϭ contrast-to-noise ratio; CTDI vol ϭ volume CT dose index; FBP ϭ filtered backprojection; IMR ϭ iterative model reconstruction; MBIR ϭ model-based iterative reconstruction; IR ϭ iterative reconstruction

Zellweger syndrome, also referred to as cerebrohepatorenal syndrome, is a rare autosomal recessive disease representing the most severe form of the peroxisomal biogenesis disorders. Neuroanatomical sequelae include impaired neuronal migration, diffuse hypomyelination, and sensorineural degeneration. Due to the rare and severe nature of this disorder, early mortality, and comorbidities that place the patient at risk for sedated imaging, high-resolution magnetic resonance imaging findings of Zellweger syndrome are scarce in the literature. Presented here is a case of this rare disease imaged at 3.0 Tesla.