Contrast-Enhanced Helical CT of the Head and Neck

Contrast Medium Use in Computed Tomography for Patients Presenting with Headache: 4-year Retrospective Two-Center Study in Central and Western Regions of Ghana

Background

Contrast medium (CM) administration during computed tomography (CT) enhances the accuracy in the detection and interpretation of abnormalities. Evidence from literature also validate the essence of CM in imaging studies. CT, by virtue of its ubiquity, ease of use, speed, and lower financial footprint, is usually the first investigation in cases of headache. Through a multicenter retrospective analysis, we compared findings of contrast-enhanced CT (CECT) to noncontrast-enhanced CT (NCECT) head examinations among patients presenting with headache.

Methods

A multicenter retrospective analysis of four years' CT head examination data at two radiology centers located in Central and Western Regions of Ghana were reviewed. Records of patients who presented with headache as principal complaint between January 2017 and December 2020 were reviewed. A total of 477 records of patients with headache were identified, retrieved and evaluated. A Chi-square test and Fisher exact test were used to compare the CECT and NCECT groups. Binary logistic regression analysis was computed to assess association between CECT and each CT findings. Statistical significance was considered at p < 0.05 with a 95% confidence interval.

Results

A significant proportion of the patients was females (51.8% in CECT and 60% in NCECT). The NCECT group (40.06 ± 14.76 years) was relatively older than the CECT group (38.43 ± 17.64 years). There was a significant difference between the CECT and NCECT in terms of age (p=0.002) and facility CT was performed (p < 0.0001). The rate of abnormalities was higher in CECT (43.5%, 166/382) compared NCECT (37.9%, 36/95). There was no significant association between CT head findings and contrast enhancement.

Conclusion

CECT examination accounted for 5.6% increase in the detection of head abnormalities. Efforts required to establish local standard operation procedures (SOPs) for contrast medium use especially in CT head examinations. Further studies to improve the knowledge of agents, mechanism of action, and safety of contrast media used among practitioners in Ghana is recommended.

Diagnostic Imaging of Oral and Maxillofacial Anatomy and Pathology

This article describes the technical principles and indications for the most often encountered diagnostic imaging modalities in veterinary dentistry and oral surgery; with extensive coverage of intraoral (and extraoral) dental radiographic imaging and interpretation through detailed example figures of common dental and maxillofacial diseases in the dog and cat. Multidetector/multislice computed tomography (MDCT/MSCT) and emergent technologies such as cone-beam computed tomography (CBCT) are presented here in detail. Magnetic resonance imaging (MRI) and diagnostic ultrasound, which are used less frequently, are briefly discussed.

Computerised tomography and magnetic resonance imaging of laryngeal squamous cell carcinoma: A practical approach

Squamous cell carcinoma is the most common head and neck cancer. This review describes the state-of-the-art computerised tomography and magnetic resonance imaging protocols of the neck and the normal larynx anatomy, and provides a practical approach for the diagnosis and staging of laryngeal squamous cell carcinoma.

Síndrome do granuloma letal da linha média: um dilema diagnóstico

A rara síndrome do granuloma letal da linha média apresenta difícil diagnóstico, em razão da grande variedade de doenças que podem causá-la e um desconhecimento pela maioria da classe médica. No presente artigo relatamos caso de paciente com esta doença, provocada por carcinoma epidermoide, chamando a atenção para os diagnósticos diferenciais e aspectos clínico-radiológicos que podem auxiliar no diagnóstico.

Improved edge delineation using a low-flow and delayed-phase contrast-enhanced protocol for computed tomography imaging of oral cavity and oropharyngeal malignancies

AIM

To determine whether contrast-enhanced computed tomography (CT) performed with a high flow rate and short delay protocol or a lower flow rate and longer delay protocol resulted in better enhancement of the oral cavity and oropharyngeal tumour and tumour edge delineation.

MATERIALS AND METHODS

Patients with squamous cell carcinomas of the upper aerodigestive tract (UAT) who underwent contrast-enhanced CT using 100 ml contrast material with 300 mg iodine/ml were selected for this comparison study. The protocols studied used a high flow rate and short scan delay (2 ml/s and 50 s) and a lower flow rate and longer delay (1 ml/s and 100 s). Contrast enhancement by radiodensity in Hounsfield units of the tumour site, poorest and clearest tumour boundaries and contralateral lateral pterygoid muscle were measured using a region of interest tool. A t-test statistical analysis was used to compare both protocols.

RESULTS

The lower flow and longer delay protocol maximized contrast differences at both the poorest and clearest definition boundaries of the tumour (p ≤ 0.01 and p ≤ 0.05, respectively) and the pterygoid muscle (p ≤ 0.01). There was no significant difference in contrast enhancement within the central homogeneous tumour site.

CONCLUSION

A lower flow and longer delay protocol (1 ml/s and 100 s) provided better enhancement of the delineation of the tumour edge and surrounding musculature than a high flow rate and short delay protocol (2 ml/s and 50 s). Both protocols achieved similar central tumour enhancement.

Basal Cell Adenoma of the Parotid Gland

OBJECTIVE

The goal of this study was to report the radiologic characteristics of basal cell adenoma of the parotid gland, which is a relatively rare neoplasm.

METHODS

A radiology and otolaryngology specialist reviewed the 2-phase helical computed tomography (CT) (n = 6) and/or magnetic resonance (MR) imaging (n = 2) scans of 7 patients with basal cell adenoma. The authors evaluated the imaging characteristics, including tumor size, location, contour and margin, internal density or signal intensity, contrast enhancement pattern, and presence of calcification. The imaging features were then analyzed and correlated with the pathologic findings.

RESULTS

All the tumors presented as small (less than 3 cm), well-encapsulated, round or oval masses on CT or MR imaging. On the 2-phase CT scan, the mostly solid-looking tumors (n = 4) showed marked contrast enhancement on the early phase, and there was a subsequent decrease in attenuation on the delayed phase. These tumors were classified as the solid subtype on histologic examination. Meanwhile, the tumors with large cystic areas (n = 2) showed gradual and additional enhancement on the delayed phase and were classified as the tubular or trabecular subtype on pathologic evaluation. There were small spots of low attenuation in the tumors of the solid subtype, which were proved to be intratumoral microcysts in the pathologic correlation. Calcification was found in a tumor.

CONCLUSIONS

Basal cell adenomas of the parotid gland present as small well-marginated tumors and appear as masses with central large cysts or solid masses with microcysts on CT and MR imaging scans. Basal cell adenomas of the parotid gland had at least 2 different enhancement patterns on the 2-phase helical CT scans, and the enhancement patterns and imaging architecture were related to the histologic subtype of the tumors.