Can MRI replace CT in evaluating semicircular canal dehiscence?

BACKGROUND AND PURPOSE: Patients with symptoms of semicircular canal dehiscence often undergo both CT and MR imaging. We assessed whether FIESTA can replace temporal bone CT in evaluating patients for SC dehiscence. MATERIALS AND METHODS: We retrospectively reviewed 112 consecutive patients (224 ears) with vestibulocochlear symptoms who underwent concurrent MR imaging and CT of the temporal bones between 2007 and 2009. MR imaging protocol included a FIESTA sequence covering the temporal bone (axial 0.8-mm section thickness, 0.4-mm spacing, coronal/oblique reformations; 41 patients at 1.5T, 71 patients at 3T). CT was performed on a 64-row multidetector row scanner (0.625-mm axial acquisition, with coronal/oblique reformations). Both ears of each patient were evaluated for dehiscence of the superior and posterior semicircular canals in consensual fashion by 2 neuroradiologists. Analysis of the FIESTA sequence and reformations was performed first for the MR imaging evaluation. CT evaluation was performed at least 2 weeks after the MR imaging review, resulting in a blinded comparison of CT with MR imaging. CT was used as the reference standard to evaluate the MR imaging results. RESULTS: For SSC dehiscence, MR imaging sensitivity was 100%, specificity was 96.5%, positive predictive value was 61.1%, and negative predictive value was 100% in comparison with CT. For PSC dehiscence, MR imaging sensitivity was 100%, specificity was 99.1%, positive predictive value was 33.3%, and negative predictive value was 100% in comparison with CT. CONCLUSIONS: MR imaging, with a sensitivity and negative predictive value of 100%, conclusively excludes SSC or PSC dehiscence. Negative findings on MR imaging preclude the need for CT to detect SC dehiscence. Only patients with positive findings on MR imaging should undergo CT evaluation.

Field evaluations of concentrated spray applications of microencapsulated sex pheromone for codling moth (Lepidoptera: Tortricidae).

The application of a microencapsulated (MEC) sex pheromone formulation (Checkmate CM-F) for codling moth, Cydia pomonella (L.), in low volume, concentrated sprays was evaluated in a series of small plot and grower trials in apple, Malus domestica Borkhausen, and pear, Pyrus communis L. Preliminary tests found that MEC sprays applied at 172-207 kilopascals in 12-23 liters/ha deposited the highest density of microcapsules per leaf. The addition of a latex sicker did not increase the deposition of microcapsules. Small plot tests in 2004 compared the effectiveness of two low-volume sprayers against a standard high-volume spray (926 liters/ha) applied at 1,379 kilopascals. Moth catches and fruit injury were significantly lower in plots treated with the low-volume sprays compared with plots treated with the standard sprayer. These results suggest that concentrating the MEC formulation increases the deposition of microcapsules and improves its effectiveness. Larger trials were conducted with a low-volume sprayer in 4-ha plots within commercial apple (2005-2006) and pear orchards (2005) paired with similar plots treated with hand-applied pheromone dispensers. Levels of fruit injury were not significantly different between pheromone treatments in any of the three tests. Moth catches, however, were significantly higher in the MEC- versus the dispenser-treated apple plots in 2005. No difference was found in the fruit injury levels in MEC-treated apple orchards in 2005 caused by irrigation method, but moth catches were significantly higher in overhead versus undertree orchards. The advantages and current limitations of using MEC sex pheromone sprays to supplement current grower's management strategies for codling moth is discussed.

Sinonasal inflammatory disease: pathophysiology, imaging, and surgery.

The body of literature regarding imaging inflammatory diseases of the sinonasal cavity is extensive. This article will not recapitulate standard imaging protocols, osteomeatal complex (OMC) anatomy, or drainage pathways to any significant extent. Clinical and radiographic topics that create confusion for radiologists will be covered in some depth to include the pathophysiology of rhinosinusitis and bone response to inflammation. Fungal sinusitis is covered elsewhere in this issue. Clinical imaging issues will be followed by a discussion of common surgical procedures, their complications, and postoperative recurrent disease. The role of MRI as a problem-solving modality will be emphasized.

Petrous apex and cavernous sinus: anatomy and pathology.

The cavernous sinus (CS) and petrous apex (PA) are contiguous. The cavernous space and cranial nerves III and VI are intimately associated with each. To accurately interpret computed tomography (CT) and magnetic resonance (MR) images of this region, one must understand thoroughly the anatomy of the PA and CS. This article begins with a detailed review of this anatomy, followed by a discussion of pathology. Intrinsic diseases of the CS and PA are emphasized specifically.

Primary mucocele of the petrous apex: MR appearance.

Mucoceles of the petrous apex are rare. Their MR appearance varies depending on the degree of hydration or inspissation of the contents. Concise preoperative diagnosis is helpful, since mucoceles are better drained to the mastoids via an infralabyrinthine approach rather than the more risky middle cranial fossa approach used for cholesteatomas.