RADIOLOGY CORNER

Military Medicine, Jul 2006 by Ly, Justin Q, Sanders, Timothy G, Smirniotopoulos, James G, Folio, Les

Answer to last month's radiology case and image: Subdural Hematoma

(Case # 3 appears at the end of this article)

Introduction: An 18-year-old Hispanic male was brought by ambulance to the Emergency Department status post high-speed motor vehicle collision in which the patient was ejected from his vehicle. He was lethargic on presentation, but without evidence of any focal neurological deficits. Physical examination in the trauma bay showed swelling over his left temporal region and scattered facial abrasions. A noncontrast head CT was immediately obtained (Fig. 1).

Imaging Findings: The noncontrast head CT revealed a small subdural hematoma, with a dense appearance consistent with the acute injury (Fig. 1a). There is pneumocephalus, seen as small bubbles of air within the small left extraaxial parietal subdural collection as well as a single focus of air posteriorly at the left paramidline aspect of the extra-axial space shown (Fig. 1a). These findings indicate that a fracture has occurred, allowing communication of outside air or a sinus cavity with the intracranial space. Indeed a complex adjacent temporal bone fracture was detected and best appreciated on bone windows (Fig. 1b).

Discussion: Subdural hematomas are common injuries in both military active duty and their dependents including children subject to nonaccidental trauma. The subdural hematoma (SDH) is a potentially devastating yet curable extra-axial fluid collection classically associated with head trauma. Mechanism of injury includes rapid acceleration or deceleration that produces tearing of the bridging veins as they cross from brain to durai sinus. Clinical manifestations are usually nonfocal and nonspecific. Careful history taking and an appropriate degree of clinical suspicion is necessary for timely diagnosis. A noncontrast head CT is fast, highly accurate, and with few exceptions, should always be the first study obtained in the evaluation of acute head trauma. Treatment of nonacute subdural hematoma involves craniotomy-guided hematoma evacuation. Drainage via craniostomy has become the treatment of choice for acute subdural hematoma because of its low morbidity and mortality (1).

The full-text version is available in a downloadable PDF file on the AMSUS page of the USUHS website at: http://rad.usuhs.mil/amsus.html

Differential considerations for subdural hematoma include epidural hematoma, subdural hygroma, and subdural empyema. Epidural hematomas are classically lens-shaped ("lenticular") but, unlike subdurals, are confined or limited by the cranial sutures. Subdural hygromas are frequently a delayed complication of head trauma and can mimic the appearance of a subdural hematoma (2).

CASE #3

The answer to this case will appear in the August issue of Military Medicine

The opinions or assertions contained herein are the private views of the authors and not to be construed as official or reflecting the views of the Uniformed Services University of the Health Sciences or the Department of Defense.

History: 38-year-old man with heart murmur on physical exam. Electrocardiogram-gated MR of the chest was performed and included axial black blood images (Figure A) and oblique sagittal cine bright blood images (Figure B, systolic image). Oblique axial bright blood cine phase contrast images (Figure C, systolic image) through the base of the heart through the aortic valve plane was also performed and demonstrated a lens-shaped (arrowheads) aortic opening.

References:

1. Kamezaki T, Yanaka K, Fujita K, Nakamura K, Nagatomo Y, Nose T. Traumatic acute subdural hygroma mimicking acute subdural hematoma. J Clin Neurosci. 2004; 11:311-3.

2. Weigel R, Krauss JK, Schmiedek P. Concepts of neurosurgical management of chronic subdural haematoma: historical perspectives. Br J Neurosurg. 2004;18:8-18.

sase provided by:

Capt Justin Q. Ly, MC, USAF1; Col Timothy G. Sanders, MC, USAF (Ret.)2; James G. Smirniotopoulos, M.D.2: Col Les Folio, MC, SFS 2

1 Wilford Hall Medical Center

2 Uniformed Services University of the Health Sciences