Emergent pediatric US: what every radiologist should know.

Appendicitis, intussusception, and hypertrophic pyloric stenosis (HPS) are three of the most common reasons for emergent abdominal imaging in pediatric patients. Although the use of computed tomography has risen dramatically over the past 2 decades, children are particularly at risk for the adverse effects of ionizing radiation, and even low-dose radiation is associated with a small but significant increase in lifetime risk of fatal cancer. In most emergency departments, the use of magnetic resonance (MR) imaging as a primary modality for the evaluation of a child with abdominal pain remains impractical due to its high cost, its limited availability, and the frequent need for sedation. Ultrasonography (US) does not involve ionizing radiation and, unlike MR imaging, is relatively inexpensive, is widely available, and does not require sedation. Another major advantage of US in abdominal imaging is that it allows dynamic assessment of bowel peristalsis and compressibility. Delayed diagnosis of any of the aforementioned disease processes can lead to serious morbidity and, in some cases, death. The ability to diagnose or exclude disease with US should be part of a core radiology skill set for any practice that includes a pediatric population.

Abbreviated MRI for patients presenting to the emergency department with hip pain.

OBJECTIVE: The objective of our study was to assess the diagnostic performance of two abbreviated hip MRI protocols--coronal STIR images only and coronal STIR with coronal T1-weighted images--as compared with a full hip MRI protocol in patients presenting to the emergency department (ED) with hip pain and negative radiographic findings. MATERIALS AND METHODS: The cohort included 385 patients (277 females, 108 males; mean age, 61 years; age range, 16-99 years) who underwent MRI within 1 month of negative radiographs obtained for ED evaluation of hip pain between January 2000 and March 2009. MR examinations were graded independently by two musculoskeletal fellowship-trained emergency radiologists for detection of fracture, avascular necrosis (AVN), and muscle injury in three subsets: coronal STIR images only; coronal STIR images and coronal T1-weighted images; and the full examination. RESULTS: MRI detected findings suspicious for fracture in 42% (162/385) of patients, for AVN in 9% (33/385), and for muscle injury in 35% (134/385). The sensitivity and specificity of STIR alone in raising concern for fracture was 99% (220/223) for both readers, with small incremental benefits of adding coronal T1-weighted images. For AVN, specificity was 100% (28/28) with STIR alone, but the addition of coronal T1-weighted images provided substantial benefit by increasing sensitivity from 85% (28/33) to 97% (32/33). For muscle injury, sensitivity and specificity exceeded 95% (128/134) for both abbreviated examinations. CONCLUSION: An abbreviated MRI protocol including coronal STIR and coronal T1-weighted images has high sensitivity and specificity for fracture, AVN, and muscle injury in ED patients presenting with hip pain and negative radiographs.

Imaging of trauma in a pregnant patient.

Trauma is the number one nonobstetric cause of maternal death. This chapter presents the latest consensus from the literature on the best approach to radiographic imaging of these patients. The central issues of discussion include the rationale and protocols for screening for pregnancy in trauma setting; the effects of radiation and its risks to the fetus; obtaining informed consent; how to estimate fetal dose; and the role of ultrasound, computed tomography, and magnetic resonance imaging, including the intravenous contrast agents used for the assessment of abdominal trauma. The team approach to the management of these patients is also highlighted.

Abdominal anaphylaxis presenting as trauma: a recipe for delayed diagnosis.

BACKGROUND: Successful shock management requires prompt identification, classification, and treatment; however, the triage of patients with non-hemorrhagic shock to the trauma room can lead to delayed diagnosis with increased morbidity and mortality. OBJECTIVE: Our goal is to emphasize the importance of shock identification and classification to facilitate the delivery of the appropriate and timely therapy, no matter how the patient is triaged. CASE REPORT: We describe a patient triaged as a trauma patient with suspected hemorrhagic shock yet who was found to have anaphylaxis as the etiology of his condition. Abdominal anaphylaxis, a less recognized presentation of anaphylaxis, is reviewed and discussed. CONCLUSIONS: We hope to increase awareness of a less common presentation of anaphylaxis and discuss its management.

Dynamic infrared imaging for the detection of malignancy.

The potential for malignancy detection using dynamic infrared imaging (DIRI) has been investigated in an animal model of human malignancy. Malignancy was apparent in images formed at the vasomotor and cardiogenic frequencies of tumour bearing mice. The observation of malignancy was removed by the administration of an agent that blocks vasodilation caused by nitric oxide (NO). Image patterns similar to those that characterize malignancy could be mimicked in normal mice using an NO producing agent. Apparently DIRI allows for cancer detection in this model through vasodilation caused by malignancy generated NO. Dynamic infrared detection of vasomotor and cardiogenic surface perfusion was validated in human subjects by a comparison with laser Doppler flowmetry (LDF). Dynamic infrared imaging technology was then applied to breast cancer detection. It is shown that dynamic infrared images formed at the vasomotor and cardiogenic frequencies of the normal and malignant breast have image pattern differences, which may allow for breast cancer detection.

Detection of breast malignancy: diagnostic MR protocol for improved specificity.

PURPOSE: To prospectively determine if a combined magnetic resonance (MR) protocol that includes T1-weighted dynamic contrast agent-enhanced (DCE) MR imaging, hydrogen 1 (1H) MR spectroscopy, and T2*-weighted perfusion MR imaging improves specificity in the diagnosis of breast cancer. MATERIALS AND METHODS: The combined MR imaging-MR spectroscopy protocol was performed in 50 patients after positive findings at mammography but prior to biopsy. Single-voxel proton MR spectroscopy and perfusion MR imaging were conducted only if DCE MR images showed rapid contrast enhancement in the lesion. Biopsy results were used as the reference for comparison with MR results and for calculation of sensitivity and specificity in the detection of breast malignancy. RESULTS: DCE MR imaging alone showed 100% sensitivity and 62.5% specificity. The specificity improved to 87.5% with the addition of 1H MR spectroscopy and to 100% with the further addition of perfusion MR imaging. Twenty-eight patients underwent both MR spectroscopy and perfusion MR imaging. Two patients underwent MR spectroscopy but declined to undergo perfusion MR imaging. The remaining 20 patients had negative results at DCE MR imaging and therefore did not undergo the additional examinations. CONCLUSION: The combined MR protocol of DCE MR imaging, 1H MR spectroscopy, and perfusion MR imaging has high sensitivity and specificity in the diagnosis of breast cancer.