Usefulness of multidetector row computed tomography in the assessment of the pathways of spreading of neck infections to the mediastinum.

Descending necrotizing mediastinitis (DNM) is an uncommon disease and may be lethal if not treated adequately and promptly. In all settings, multidetector row computed tomography (MDCT) is the most valuable tool to assess the presence and extension of the disease when DNM is clinically suspected. The key point for an accurate diagnosis of descending necrotizing mediastinitis is to establish the pathway of spreading of the neck soft-tissue infection to the mediastinum on axial and reformated multidetector row computed tomography images. The aims of this article are to describe the relevant anatomy of the pathways of neck infection to the mediastinum; to analyze the most characteristic computed tomography features of DNM, and to discuss the impact of computed tomography in the management and in the surgical therapy of these patients.

Regarding three cases of descending necrotizing mediastinitis: spiral CT assessment.

Descending necrotizing mediastinitis (DNM) is a rare and life-threatening complication of deep neck space infection which occurs when infection spreads from the deep spaces of the neck, propagating within the soft tissue into the mediastinal spaces. The disease has a high mortality rate due to frequent delay in diagnosis and treatment. Computed Tomography (CT) is important in determining the level of infection, showing the presence and extension of fluid collections (with or without gas bubbles) and diffuse soft-tissue infiltration of the mediastinal fat, and indicating the best surgical approach and progress of treatment. Three cases of DNM evaluated with spiral CT from June 1999 to June 2001 are presented.

Assessment of the diagnostic capacity of planar scintigraphy and SPECT with 99mTc-HMPAO-labelled leukocytes in superficial and deep sternal infections after median sternotomy.

Sternal infection is a rare complication of median sternotomy but is associated with considerable morbidity and mortality, particularly in the case of deep sternal infection (mediastinitis). Successful treatment depends on early diagnosis and on the location (deep or superficial) of the infection. Radiological techniques have many limitations, and although 67Ga scintigraphy is effective, it delays diagnosis by 48 h. We assessed the diagnostic capacity of planar scintigraphy and single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (HMPAO)-labelled leukocytes in deep sternal infections after median sternotomy. We prospectively studied 41 patients with clinical suspicion of deep sternal infection 4 and 20 h after administration of the tracer. The final diagnosis was deep sternal infection in nine patients and superficial sternal infection in 10, with infection being ruled out in 22 patients. Planar scintigraphy did not detect any of the deep sternal infections at either 4 h or 20 h. SPECT correctly identified eight of the nine deep sternal infections at 4 h and all seven at 20 h, with no false positive results. Planar scintigraphy identified 16 of the 18 superficial sternal infections at 4 h and all of them at 20 h. SPECT identified 17 of these 18 infections at 4 h and all of them at 20 h. Other infections unrelated to the sternotomy were identified in seven patients. Leukocytes labelled with 99mTc-HMPAO are a highly reliable method for the early diagnosis of sternal infections after median sternotomy. Use of SPECT allows determination of the depth of the infection and differentiation of superficial from deep sternal infections. It is also possible to detect other sites of infection, thus providing alternative diagnoses.