Biphasic CT imaging of deep neck infections (DNIs): how does dual injection mode helps in differentiation between types of collections?

Abstract

Background Deep neck infections are showing resurgence in the current era and still pose threatening diagnosis. CT is the gold standard imaging modality; still, the reported low sensitivity and specificity was suggested in view of monophasic injection technique. The purpose of the study was to discuss the diagnostic accuracy of CT with biphasic mode of injection using and a single scanning phase. The first 50–60 cc of IV contrast are injected at a slow rate of 1 cc/s to (tissue impregnation phase). The other 50–60 cc was injected at a high rate of 2 cc/sec, approximately 1 min after the first injection. The single phase of scanning is made followed by multi-planar image analysis of collection. Discrimination of abscess versus phlegmon is made according to described criteria. Results Radiological diagnosis was made of 64/66 cases of abscess and two cases only had phlegmon. The 64 cases of abscess underwent drainage by ENT surgeon showing correctly diagnosed drainable abscess in 59 out of 64 cases and 5 falsely diagnosed as abscess proved to be non-drainable phlegmon. The two patients with radiological diagnosis of non-drainable phlegmons were correctly diagnosed. Conclusion The study achieved a high accuracy of 92%. This is likely attributed to dual-phase technique that allows enhancement of the core of a phlegmon by slow interstitial phase, while combined dual injections allow enhancing the “rim enhancement sign” of abscess.

Diagnostic accuracy of contrast-enhanced CT for neck abscesses: A systematic review and meta-analysis of positive predictive value

“…Regarding the contrast agent, there is currently no consensus on the optimal amount or speed of administration or the delay between administration and imaging. A recent study found high PPV (0.92) for CT with a biphasic mode of contrast infection and a single scan phase [ 50 ]. The biphasic injection consists of a double mode of injection with single scanning.…”

“…The biphasic contrast injection is suggested to allow better delineation of the abscess walls of different maturations and thus enhance differentiation. However, the superiority of this method lacks scientific studies in comparison to conventional single-phase contrast injections [ 50 ].…”

Odontogenic Head and Neck Region Infections Requiring Hospitalization: An 18-Month Retrospective Analysis

“…The clinical picture of deep fascial infections of the head and neck may not correlate with the worsening of the patient's general condition. The standard diagnostic imaging approach involves computed tomography with contrast [ 27 – 29 ], which allows for precise location and differentiation of inflammatory disease from other pathologies, such as cysts, tumors, and metastatic lymph nodes [ 30 ].…”

Management of Deep Neck Space Infections: A Large Tertiary Center Experience

“…This can be demonstrated by the use of a contrast medium, which accumulates in inflamed tissues. Intravenous contrast also provides a clear visualization of bony and soft tissue structures of the head and neck, allows identification of the great neck vessels, and highlights the areas of inflammation, the collections, and the suspected complications [20]. The differential diagnosis between abscess and cellulitis/phlegmon is critical because surgical drainage is indicated only in the former case [21].…”