Atretic cephalocele and differential considerations: A small case series.

Any posterior midline cystic or soft tissue scalp mass in an infant needs evaluation with MRI brain and MRV brain to look for intracranial extension of the lesion. One of the differential considerations is an atretic cephalocele, which can be a difficult diagnosis, especially when the cystic lesions are small. The presence of a small calvarial defect adjacent to the cystic mass and a persistent primitive falcine vein, which points towards the cystic mass, are imaging clues to this diagnosis. Correct diagnosis is needed prior to surgical resection to avoid potentially serious postoperative complications.

Postoperative Pharynx and Larynx.

Cancers of the pharynx and larynx are treated using a combination of chemotherapeutic, radiation, and surgical techniques, depending on the cancer type, biology, location, and stage, as well as patient and other factors. When imaging in the postsurgical setting, the knowledge of the type of tumor, preoperative appearance, and type of surgery performed is essential for accurate interpretation. Surgical anatomic changes, surgical implants/devices, and potential postsurgical complications must be differentiated from suspected recurrent tumors.

Tractography of the arcuate fasciculus in healthy right-handed and left-handed multilingual subjects and its relation to language lateralization on functional MRI.

Functional MRI (fMRI) enables evaluation of language cortical organization and plays a central role in surgical planning. Diffusion Tensor Imaging (DTI) or Tractography, allows evaluation of the white matter fibers involved in language. Unlike fMRI, DTI does not rely on the patient's cooperation. In monolinguals, there is a significant correlation between the lateralization of language on fMRI and on DTI. Our objective is to delineate the arcuate fasciculus (AF) in right- and left-handed trilinguals and determine if the AF laterality on DTI is correlated to language lateralization on fMRI. 15 right and 15 left-handed trilingual volunteers underwent fMRI and DTI. Laterality Index was determined on fMRI (fMRI-LI). Mean Diffusivity, Fractional Anisotropy (FA), Number of Fibers, Fiber Length, Fiber Volume and Laterality Index (DTI-LI) of the AF were calculated on DTI. 28 of the 30 subjects presented a bilateral AF. Most subjects (52%) were found to have a bilateral language lateralization of the AF on DTI. Only 4 subjects had bilateral lateralization of language on fMRI. The right AF demonstrated lower diffusivity than the left AF in the total participants, the right-handed, and the left-handed subjects. FA, Volume and Length of the AF were not significantly different between the two hemispheres. No correlation was found between the DTI-LI of the AF and the fMRI-LI. A prominent role of the right AF and a bilateral structural organization of the AF was present in our multilingual population regardless of their handedness. While in prior studies DTI was able to determine language lateralization in monolingual subjects, this was not possible in trilingual highly educated subjects.

Functional MRI study of language organization in left-handed and right-handed trilingual subjects.

Functional MRI (fMRI) is gaining importance in the preoperative assessment of language. Selecting the appropriate language to test by fMRI in trilingual patients is intricate. Our objective is to compare fMRI maps for all three languages in left- and right-handed trilingual subjects. 15 right- and 15 left-handed trilingual volunteers were included in the study. We performed fMRI for each volunteer with a visual responsive naming paradigm that was repeated three times, once in each language. The activated areas and the laterality indices were calculated and correlation with the age of acquisition and proficiency of each language was determined. Strong statistical correlation was found between the Laterality Index (LI) of the three languages, in both the right and left-handed groups. Discordant lateralization of language was only observed in four left-handed subjects who demonstrated bilateral and left-lateralization. In right-handed subjects, the activation maps for the first and the second acquired language were similar. The largest activation was seen with the last acquired language. Irrespective of language proficiency and age of acquisition, the language lateralization might change for left-handed subjects. In right-handed subjects, there is no change and the last acquired language results in the largest activation. fMRI performed for a single language can accurately determine language lateralization in right-handed subjects, whereas in left-handed subjects, it is mandatory to test all languages.

Pituitary Adenoma and Papillary Craniopharyngioma: A Rare Case of Collision Tumor and Review of the Literature.

BACKGROUND: Pituitary adenomas are the most common lesion of the sellar region. Very few cases in the literature have described their association with craniopharyngiomas in the same anatomic compartment, an entity defined as collision tumors of the sella. CASE DESCRIPTION: A 35-year-old man presented with headaches and progressive visual disturbances. Radiographic imaging initially highlighted the presence of a pituitary craniopharyngioma. An endoscopic transsphenoidal pituitary approach was performed, during which the tumor was partially resected. The pathology report was positive for 2 entities: a nonfunctioning pituitary adenoma and a papillary craniopharyngioma. This was an unexpected diagnosis based on the surgical and initial radiologic findings. CONCLUSIONS: To our knowledge, this is the first documented case of a collision tumor of the sella comprising a pituitary adenoma and a craniopharyngioma of the papillary type.

Comparison of accelerated 3-D spiral chemical shift imaging and single-voxel spectroscopy at 3T in the pediatric age group.

Single-voxel spectroscopy (SVS) is usually used in the pediatric population when a short acquisition time is crucial. To overcome the long acquisition time of 3-D phase-encoded chemical shift imaging (CSI) and lack of spatial coverage of single-voxel spectroscopy, efficient encoding schemes using spiral k-space trajectories have been successfully deployed, enabling acquisition of volumetric CSI in <5 min. We assessed feasibility of using 3-D spiral CSI sequence routinely in pediatric clinical settings by comparing its reconstructed spectra against SVS spectra. Volumetric spiral CSI obtained spectra from 2-cc isotropic voxels over a 16×16×10-cm region. SVS acquisition encoded a 3.4-cc (1.5-mm) isotropic voxel. Acquisition time was 3 min for every technique. Data were gathered prospectively from 11 random pediatric patients. Spectra from left basal ganglia were obtained using both techniques and were processed with post-processing software. The following metabolite ratios were calculated: N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), lactate/creatine (Lac/Cr) and N-acetylapartate/choline (NAA/Cho). We collected data on 11 children ages 4 days to 10 years. In 10/11 cases, spectral quality of both methods was acceptable. Considering 10/11 cases, we found a statistically significant difference between SVS and 3-D spiral CSI for all three ratios. However, this difference was fixed and was probably caused by a fixed bias. This means that 3-D spiral CSI can be used instead of SVS by removing the mean difference between the methods for each ratio. Accelerated 3-D CSI is feasible in pediatric patients and can potentially substitute for SVS.

Imaging findings of atypical mycobacterial infection in the temporal bone.

Atypical mycobacterial (AM) infection of the temporal bone is rare, and its early diagnosis is critical for a good patient outcome. The imaging findings of AM infection have been only briefly reported. We present the computed tomographic and magnetic resonance findings of AM involvement of the entire temporal bone in an immunocompromised patient, and we discuss the differential diagnosis. The scattered areas of both bone sclerosis and erosion may help the radiologist suggest the diagnosis of an indolent process such as tuberculosis or AM and allow initiation of early treatment.