Recent advances in 4DFlow MRI (Phase Contrast MRA) acquisition and reconstruction enable high resolution exams to be obtained in practical imaging times. 4DFlow MRI provides images of vascular morphology and quantitative measurements of blood velocity throughout a 3D imaging volume. Hemodynamic parameters such as flow volume, relative wall shear stress, streamlines, vorticity and pressure gradients can be derived from the velocity data. The combination of anatomic vessel wall imaging, lumen visualization and physiologic data derived from accelerated 4DFlow MRI augments the characterization of intracranial arterial stenosis, aneurysms, vascular malformations and dural sinus pathology. This review provides an update for clinicians interested in 4DFlow MRI of the brain.

Pertussis, or whooping cough, is a highly contagious respiratory illness caused most frequently by Bordetella pertussis. Clinical presentation ranges in severity, but lifethreatening illness disproportionately affects children and immunocompromised individuals. Acellular vaccines for pertussis have been available for decades, and they are recommended throughout the lifespan. A patient who had received a kidney transplant presented with respiratory distress and dry cough as manifestations of coinfection with B pertussis and Bordetella parapertussis/bronchiseptica. The goal of this case report was to highlight the importance of immunization programs at transplant centers, which are in the unique position to care for patients both with end-stage organ disease and in the post-transplant setting. K E Y W O R D S Bordetella, immunization, kidney transplant, pneumonia, transplant | 5 of 5 HOVEL Et aL. Derrick J. Chen

A previously healthy 16-year-old male patient came to the emergency department with a six-week history of left posterior hip pain following a head-on ATV collision. After failing conservative therapy, he was found to have weakness and atrophy of the left lower extremity on exam. MRI demonstrated an epidural mass that was hyperintense on T1 and hypointense on T2. Biopsy of the mass revealed a melanocytic lesion; further lesions were identified in the lungs, which biopsy proved to be malignant melanoma. Dermoscopy of the entire body, anoscopy, and retinal exam were negative for melanoma; a whole-body PET scan did not reveal any further lesions or evidence of a primary lesion. Given the lack of a primary lesion, this was thought to be a primary leptomeningeal melanoma. Primary melanomatous tumors of the spine are rare entities, with fewer than 40 cases described in the literature. This case was unique due to the patient's very young age and the presence of metastases on presentation.