Imaging of trauma: Part 1, Pseudotrauma of the spine--osseous variants that may simulate injury.

OBJECTIVE: Anatomic variants and incomplete ossification and fusion of the developing spine may result in an erroneous diagnosis of injury or disease. This article reviews some of the more common imaging findings that may present as pseudotrauma. Normal development of the spine is reviewed, including synchondroses and ossification centers. Imaging of common variants is presented, with a focus on CT. CONCLUSION: Recognition of the normal developing spine and variants can prevent an incorrect diagnosis of injury and inappropriate treatment.

Childhood subdural hemorrhage, macrocephaly, and coagulopathy associated with Prader-Willi syndrome: case report and review of the literature.

A 16-month-old girl with a history of Prader-Willi syndrome and progressive macrocephaly manifested large, bilateral, subdural hemorrhages of differing ages on magnetic resonance imaging. Subsequent evaluation revealed a deficiency of von Willebrand factor, but after repeated evaluations, no conclusive evidence of nonaccidental trauma became apparent. Subdural hemorrhages of varying ages are frequently associated with nonaccidental trauma during early childhood. However, several uncommon conditions may present as subdural hemorrhages and thus mimic nonaccidental trauma. Our patient demonstrates a combination of Prader-Willi syndrome, von Willebrand factor deficiency, and enlargement of the extra-axial spaces. All of these in isolation were associated with subdural hemorrhages. We review the scant literature on subdural hemorrhages in Prader-Willi syndrome and other conditions that mimic nonaccidental trauma.

Comparison of 3 Tesla proton MR spectroscopy, MR perfusion and MR diffusion for distinguishing glioma recurrence from posttreatment effects.

PURPOSE: To compare 3 Tesla (3T) multi-voxel and single-voxel proton MR spectroscopy (MRS), dynamic susceptibility contrast perfusion MRI (DSC), and diffusion-weighted MRI (DWI) for distinguishing recurrent glioma from postradiation injury. MATERIALS AND METHODS: We reviewed all 3T MRS, DSC and DWI studies performed for suspicion of malignant glioma recurrence between October 2006 and December 2008. Maximum Cho/NAA and Cho/Cr peak-area and peak-height ratios were recorded for both multi-voxel and single-voxel MRS. Maximum cerebral blood volume (CBV) and minimum apparent diffusion coefficient (ADC) were normalized to white matter. Histopathology and clinical-radiologic follow-up served as reference standards. Receiver operating characteristic curves for each parameter were compared. RESULTS: Forty lesions were classified as glioma recurrence (n = 30) or posttreatment effect (n = 10). Diagnostic performance was similar for CBV ratio (AUC = 0.917, P < 0.001), multi-voxel Cho/Cr peak-area (AUC = 0.913, P = 0.002), and multi-voxel Cho/NAA peak-height (AUC = 0.913, P = 0.002), while ADC ratio (AUC = 0.726, P = 0.035) did not appear to perform as well. Single-voxel MRS parameters did not reliably distinguish tumor recurrence from posttreatment effects. CONCLUSION: A 3T DSC and multi-voxel MRS Cho/Cr peak-area and Cho/NAA peak-height appear to outperform DWI for distinguishing glioma recurrence from posttreatment effects. Single-voxel MRS parameters do not appear to distinguish glioma recurrence from posttreatment effects reliably, and therefore should not be used in place of multi-voxel MRS.

Verification bias an underrecognized source of error in assessing the efficacy of medical imaging.

RATIONALE AND OBJECTIVES: Diagnostic tests are validated by comparison against a "gold standard" reference test. When the reference test is invasive or expensive, it may not be applied to all patients. This can result in biased estimates of the sensitivity and specificity of the diagnostic test. This type of bias is called "verification bias," and is a common problem in imaging research. The purpose of our study is to estimate the prevalence of verification bias in the recent radiology literature. MATERIALS AND METHODS: All issues of the American Journal of Roentgenology (AJR), Academic Radiology, Radiology, and European Journal of Radiology (EJR) between November 2006 and October 2009 were reviewed for original research articles mentioning sensitivity or specificity as endpoints. Articles were read to determine whether verification bias was present and searched for author recognition of verification bias in the design. RESULTS: During 3 years, these journals published 2969 original research articles. A total of 776 articles used sensitivity or specificity as an outcome. Of these, 211 articles demonstrated potential verification bias. The fraction of articles with potential bias was respectively 36.4%, 23.4%, 29.5%, and 13.4% for AJR, Academic Radiology, Radiology, and EJR. The total fraction of papers with potential bias in which the authors acknowledged this bias was 17.1%. CONCLUSION: Verification bias is a common and frequently unacknowledged source of error in efficacy studies of diagnostic imaging. Bias can often be eliminated by proper study design. When it cannot be eliminated, it should be estimated and acknowledged.

Extrapleural hematomas: imaging appearance, classification, and clinical significance.

PURPOSE: We sought to identify radiologic and clinical findings associated with extrapleural hematomas (EPHs), to formulate an imaging-based classification system for EPHs, and to identify any radiologic or clinical factors associated with surgical intervention. MATERIALS AND METHODS: Thirteen cases of EPH were gathered during the clinical review. An EPH was diagnosed on computed tomography (CT) if there was inward displacement of extrapleural fat by an intrathoracic peripheral fluid collection. The location and shape of each EPH were documented. For each case, the chest radiograph obtained in closest proximity to the CT acquisitions was also reviewed. The following additional data were also gathered: coexistent thoracic and nonthoracic injuries; mechanism of injury; treatment; and outcome. RESULTS: In our series, 92% of the patients (12/13) were male. The average age of the affected patients was 61 years. Most cases were related to blunt trauma (85%, 11/13). All these patients had additional injuries; rib fractures were most consistently present (81%, 9/11). All cases could be further categorized based on the appearance of their CT scan as biconvex or nonconvex. Biconvex EPHs tended to be larger than other types (average size of 4211 mL) and required surgical intervention in 80% of patients (4/5). No specific treatment was necessary in patients with nonconvex EPHs. CONCLUSIONS: EPHs occur most commonly in high-energy blunt trauma; concomitant injuries are the rule, especially rib fractures. Biconvex hematomas tend to be large, likely resulting from high-pressure bleeding. Consequently, biconvex EPHs more often require surgical intervention. Nonconvex hematomas can usually be managed conservatively.