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Purpose: To prospectively compare gadobenate dimeglumine with gadopentetate dimeglumine (0.1 mmol per kilogram body weight) for enhanced magnetic resonance (MR) imaging of central nervous system (CNS) lesions., Materials and Methods: This study was HIPAA-compliant at U.S. centers and was conducted at all centers according to the Good Clinical Practice standard. Institutional review board and regulatory approval were granted; written informed consent was obtained. Seventy-nine men and 78 women (mean age, 50.5 years +/- 14.4 [standard deviation]) were randomized to group A (n = 78) or B (n = 79). Patients underwent two temporally separated 1.5-T MR imaging examinations. In randomized order, gadobenate followed by gadopentetate was administered in group A; order of administration was reversed in group B. Contrast agent administration (volume, speed of injection), imaging parameters before and after injection, and time between injections and postinjection acquisitions were identical for both examinations. Three blinded neuroradiologists evaluated images by using objective image interpretation criteria for diagnostic information end points (lesion border delineation, definition of disease extent, visualization of internal morphologic features of the lesion, enhancement of the lesion) and quantitative parameters (percentage of lesion enhancement, contrast-to-noise ratio [CNR]). Overall diagnostic preference in terms of lesion conspicuity, detectability, and diagnostic confidence was assessed. Between-group comparisons were performed with Wilcoxon signed rank test., Results: Readers 1, 2, and 3 demonstrated overall preference for gadobenate in 75, 89, and 103 patients, compared with that for gadopentetate in seven, 10, and six patients, respectively (P < .0001). Significant (P < .0001) preference for gadobenate was demonstrated for diagnostic information end points, percentage of lesion enhancement, and CNR. Superiority of gadobenate was significant (P < .001) in patients with intraaxial and extraaxial lesions., Conclusion: Gadobenate compared with gadopentetate at an equivalent dose provides significantly better enhancement and diagnostic information for CNS MR imaging., (RSNA, 2006)

Purpose: To establish the normal variations of the postcricoid portion of the hypopharynx, esophageal verge, and cervical esophagus, as seen on computed tomographic (CT) and magnetic resonance (MR) images., Materials and Methods: One hundred twenty-one CT and 92 MR images were reviewed. Diameter and wall thickness were measured at multiple levels. Depiction of the layers of the musculature and adjacent fat planes was evaluated. The frequency and size of the tracheoesophageal lymph nodes were noted., Results: An esophageal anteroposterior diameter greater than 16 mm and lateral diameter greater than 24 mm were considered abnormal. The average wall thickness was 4.8 mm laterally and 3.8 mm posteriorly. Demonstration of the intramural fat planes of the postcricoid region decreased from the upper to the lower region of the cricoid cartilage. The ability to separate the esophageal wall from the trachea was highest at the esophageal verge and declined markedly more distally. The tracheo-esophageal groove nodes were seen more often on the right (mean size [+/- SD], 4.5 mm +/- 2.2)., Conclusion: Knowledge of the normal appearance and variations of the post-cricoid region and cervical esophagus is essential in detecting abnormalities in these areas.

Purpose: To describe the computed tomographic (CT) measurements and features that enable accurate diagnosis of congenital nasal piriform aperture stenosis (CNPAS)., Materials and Methods: The clinical and imaging features of six patients (age range, 0-11 months) with CNPAS were retrospectively evaluated and compared with those of 61 control subjects younger than 24 months., Results: The average widths of the piriform aperture in patients aged 0-3, 4-6, and 10-12 months were 4.8, 7.0, and 6.0 mm, respectively, compared with 13.4 (P < .001), 14.9, and 15.6 mm, respectively, in the age-matched control subjects. The average areas of the piriform aperture in patients in the three age groups measured 0.24, 0.46, and 0.36 cm2, respectively, compared with 0.67 (P < .001), 0.86, and 1.11 cm2, respectively, in the age-matched control subjects. The width of the nasal cavity in patients with CNPAS was in the less than 5th percentile compard with that in the control subjects. Abnormal dentition and a midline bone ridge projecting from the inferior palate were present in all six patients., Conclusion: CT measurement of the piriform aperture width is a simple and accurate method for diagnosing CNPAS; a width less than 11 mm in a term infant is considered to be diagnostic. An abnormal dentition and a bone ridge along the underside of the palate are confirmatory imaging findings.