Evolution of intramural duodenal hematomas on magnetic resonance imaging

The magnetic resonance imaging (MRI) characteristics of evolving duodenal hematomas in children are unknown. To describe the MRI changes exhibited by evolving duodenal hematomas and the likely mechanisms behind these changes. We retrospectively reviewed the MR features of intramural duodenal hematomas (6 lesions, 10 examinations) studied on a 1.5-T MR unit. All patients had clinical histories of blunt abdominal trauma or endoscopic procedures and we were able to determine the time interval between the onset and MR imaging. We evaluated and analyzed the appearance and signal intensity patterns of hematomas of varying ages and we compared the results with those in previously reported intracranial hematomas. The imaging appearances on five examinations were consistent with presence of deoxyhemoglobin. Two of these lesions were hypointense on T2-weighted images and iso- to hyperintense on T1-weighted images. Three had heterogeneous appearances on both T1- and T2-weighted images, and the bulk of the hematoma progressively increased in size and signal intensity on T2-weighted images. On the remaining five examinations, one lesion was hyperintense on T1-weighted images and iso- to hyperintense on T2-weighted images, consistent with intracellular methemoglobin, and four lesions were hyperintense on both T1- and T2-weighted images, consistent with the presence of extracellular methemoglobin. Duodenal hematoma stages were slower than those of intracranial hematomas; the acute stage spanned 2-7 days, and early and late subacute stages occurred 10-17 days after the injury. Duodenal hematomas evolve like intracranial hematomas, but slower. Signal heterogeneity is common in the acute stage. (orig.)