Fractures of the posterolateral maxillary sinus: a masticator space blowout injury?

BACKGROUND AND PURPOSE: Segmental, depressed fractures of the posterolateral maxillary sinus may occur as a result of trauma to the masticator space, previously described in association with mandibular fractures. The authors hypothesize that the fracture is due to a transient increase in pressure in the masticator space (blow out) and therefore should be seen in association with other regional fractures. MATERIALS AND METHODS: Injuries of the masticator space were retrospectively identified by searching the imaging database from January 2014 to November 2014 for keywords that would identify regional trauma. The images were reviewed for segmental depressed fractures in the posterolateral aspect of the maxillary sinus accompanied by herniation of a variable amount of masticator space fat and/or muscle into the adjacent sinus. Three neuroradiologists reviewed the images and agreed by consensus on the presence or absence of a masticator space blowout fracture. RESULTS: Forty-three zygomaticomaxillary complex (ZMC) fractures, 89 mandibular fractures, and 49 isolated zygomatic arch fractures were identified. While all of the ZMC fractures had a maxillary component, 3 of 43 (7.0 %) additional fractures met our fracture definition. Five of 89 (5.6 %) of the mandibular fractures and 6 of 49 (12.2 %) zygomatic arch fractures had an associated posterolateral maxillary fracture. CONCLUSIONS: Segmental depressed fracture of the posterolateral maxillary sinus is relatively common, occurring in conjunction with other regional injuries. The authors hypothesize that it is due to a transient increase in pressure in the masticator space and is a separate entity from other fractures of the region that may occur concurrently.

Multidetector CT of temporal bone fractures.

Temporal bone fracture is a relatively common finding among trauma patients. Before the development of high-resolution multidetector computed tomography (MDCT) imaging, fractures of the skull base and temporal bone were a challenge to diagnose clinically. With current imaging technology, most such fractures are easily detected, and the challenge now lies in predicting the severity of injury and possible complications. In this review, we discuss the detection and classification of temporal bone fractures, their distinction from pseudofractures, and the role of imaging in establishing prognosis, particularly with respect to complications.

Decreased cerebellar activity on FDG PET/CT secondary to diffuse idiopathic cerebellar calcification.

Cerebellar hypometabolism on FDG PET has been described in several conditions, for example, chronic alcohol abuse, antiepileptic medication use, multiple system atrophy, and cerebellar infarction. Corresponding cross-sectional examination is paramount in distinguishing possible etiologies because each condition has a relatively characteristic appearance. We present a case of an asymptomatic patient with diffuse cerebellar hypometabolism found incidentally on FDG PET/CT performed for suspected recurrence of gastric carcinoma. Accompanying CT images demonstrated calcification of the cerebellum and therefore confirmed the etiology of diffuse idiopathic cerebellar calcification. Identifying this diagnosis is critical for using the cerebellum as a standard to evaluate other brain structures.

Updated imaging of traumatic brain injury.

Computed tomography (CT) and magnetic resonance (MR) play important roles in the evaluation of traumatic brain injury. Modern CT scanners allow for rapid and accurate diagnosis of intracranial hemorrhage and mass effect and allow the efficient implementation of emergent CT angiography. Newer sequences, such as gradient recalled echo, susceptibility-weighted imaging, and diffusion-weighted imaging, can provide greater sensitivity for specific types of diffuse posttraumatic brain injury. MR spectroscopy can provide additional chemical information, and diffusion tensor imaging can provide information about white matter injury. Patient treatment can be optimized using the diagnostic and prognostic information derived from current imaging techniques.

Lemierre syndrome: report of five new cases and literature review.

Lemierre Syndrome (LS) is relatively rare, and its clinical features are potentially confusing. Without proper therapy, LS is associated with significant morbidity and is potentially fatal. Recognition of the imaging features of LS in the chest and the neck may permit a timely diagnosis and lead to prompt institution of appropriate therapy. The emergency imaging features of LS in five cases are reviewed with emphasis on computed tomography of the chest and neck.

Imaging of orbital trauma.

Assessing traumatic orbital injuries is an important challenge for radiologists; this assessment is even more difficult when the orbital injury is associated with injuries involving multiple organs. Common posttraumatic orbital injuries include anterior chamber injuries, injuries to the lens, open-globe injuries, ocular detachments, intraorbital foreign bodies, carotid cavernous fistula, and optic nerve injuries. Radiographic examination of the orbits is rarely performed. Ultrasonography (US) can be very useful for evaluating the globe and its contents; however, US is contraindicated if a ruptured globe is suspected. Magnetic resonance imaging may be difficult to perform emergently; it is contraindicated if there is a possibility that a metallic intraorbital foreign body is present. Computed tomography (CT) is considered to be the top choice for evaluating orbital trauma. The best protocol is to obtain thin-section axial CT scans, then to perform multiplanar reformation. When evaluating a patient with an orbital injury, the radiologist should do the following: (a) evaluate the bony orbit for fractures, note any herniations of orbital contents, and pay particular attention to the orbital apex; (b) evaluate the anterior chamber; (c) evaluate the position of the lens (the lens may be displaced, and it may be either completely or partially dislocated); (d) evaluate the posterior segment of the globe, look for bleeds or abnormal fluid collections, and evaluate for radiopaque or radiolucent foreign bodies; and (e) evaluate the ophthalmic veins and the optic nerve complex, especially the orbital apex.

Longitudinal evaluation of apparent diffusion coefficient in children with neurofibromatosis type 1.

OBJECTIVES: Foci of T2-prolongation in both supra- and infratentorial brain in neurofibromatosis type-1 (NF1) patients have been called hamartoma-like NF1 lesions (HLL); however, their behavior is not consistent with this definition. Diffusion-weighted imaging has been used to study structure and cellularity of intracranial lesions. We applied this technique to characterize HLL as they change with time in pediatric patients. METHODS: We retrospectively studied 12 children (ages 2-20 years) with proven NF1. Forty lesions were studied longitudinally on multiple exams for a total of 166 measurements. Apparent diffusion coefficients (ADCs) were also obtained from a comparison group comprising 14 normal children (ages 2-16 years). RESULTS: The ADC for the lesions was generally greater than normal brain. Both supra- and infratentorial lesions had increasing ADC with patient age. This is contrasted to our comparison group of normal subjects who showed decreasing ADC with age. Linear regression analysis of infratentorial lesions yielded a slope of 2.70 x 10(-6) mm2 x s(-1) x year(-1) versus a slope of 17.57 x 10(-6) mm2 x s(-1) x year(-1) for supratentorial lesions. CONCLUSIONS: Our observed increase in ADC of lesions in pediatric patients with NF1 suggests increasing water in the extracellular space and/or decreasing cellularity with patient age. This change may be due to increased number or size of myelin vacuoles in NF1 lesions. Supratentorial lesions had a statistically significant increase in the rate of change of ADC compared with infratentorial lesions which may reflect an intrinsic difference in the lesion or similar lesions expressed in different environments.