This part 1 in a 2-part series illustrates vascular complications such as pseudoaneurysms, splanchnic venous thrombosis, and subscapular hematoma of the liver and spleen. Complications associated with fistulous formation, including pancreatico-psoas and pancreatico-pleural fistulas, are discussed.

Spine injury and vertebral fractures are common occurrences and can be life changing or fatal. As part of the patient care team, the radiologist is often the first to diagnose spine injury. The AO Spine is the largest spine surgery research institution in the world. AO Spine has developed a standardized spine injury classification for the entire spine which has undergone review and clinical validation with surgeons worldwide to evaluate and demonstrate reproducibility. Using AO Spine classification, the radiologist ensures shared understanding with the surgeon and trauma team, expediting appropriate care for the spine injury patient. This review outlines the classification of spine injuries of the thoracolumbar and sacral spine and provides clinical imaging and reporting examples.

Reversible cerebral vasoconstriction syndrome (RCVS) encompasses a group of clinical and radiological conditions characterized by acute onset recurrent thunderclap headaches and reversible cerebral angiopathy. The pathophysiology is largely unknown, nevertheless, research indicates several possible triggering factors and associated conditions such as stress, physical exertion, drugs or medications, and pregnancy. Neuroimaging may show multifocal narrowing and dilation of the cerebral arteries but often may be normal. Diagnosis remains difficult due to the wide range of differentials with similar clinical and imaging features. Outcomes are typically benign with supportive treatment; however, it is important for the radiologist to distinguish RCVS from other entities to exclude serious causes of morbidity and mortality to optimize management.

In the emergency radiology setting, ectopic air can frequently be a cause for alarm, such as with pneumothorax, pneumomediastinum, and portal venous gas. Ectopic air can often serve as a harbinger of serious injury, which can prompt the radiologist to notify clinicians so patients can receive appropriate care. However, there are many benign conditions which may present radiographically with air in unusual locations. It is critical to be able to recognize these benign entities, as inaccurate identification could lead to unnecessary procedures or imaging. We present numerous benign conditions which can produce air in unusual locations that we have encountered in our practice. For each condition, we will describe its etiology and will also provide key imaging findings that help to distinguish it from pathology.

French surgeon Maurice Morel-Lavallée first described a post-traumatic superficial fluid collection that occurred after a fall from a train in 1863, which was later understood to be caused by a closed degloving injury. Over time, the eponymous lesion was described specifically as occurring over the greater trochanter. Today, we understand the mechanism of degloving injuries resulting from direct or tangential shearing forces, which causes separation of the skin and subcutaneous tissues from the underlying fascia without an open defect. While commonly seen at the greater trochanter, as Morel-Lavallée initially described, radiologists today encounter closed degloving injuries in many other anatomic locations, often over bony protuberances. Prompt recognition of degloving-type injuries by radiologists is essential to ensure early treatment and prevent long-term morbidity. We present a multi-modality review of classic Morel-Lavallée lesions including a review of Morel-Lavallée-type injuries in less common anatomical locations and with less common presentations including radiographic and sonographic findings with MR correlation.