Asymmetrical or heterogeneous enhancement of the internal jugular veins in contrast-enhanced CT of the head and neck

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.

Cavernous hemangioma of infrahyoid carotid sheath and review of the literature on carotid sheath tumors

BACKGROUND

Carotid sheath may include a variety of lesions such as neurogenic or vascular, tumors originating from extra-adrenal chromaphil cells, squamous cell carcinomas, and lymphomas. Hemangiomas are benign congenital neoplasms, which, when located in the head and neck region, may be easily misdiagnosed due to their infrequent localization.

METHODS AND RESULTS

We report an unusual case of cavernous hemangioma of the infrahyoid carotid sheath presenting as palpable mass in a 51-year-old woman with no prior medical history. A review of the literature was performed to investigate the radiological and histopathological characteristics and highlight the treatment of carotid sheath lesions.

CONCLUSIONS

CT, MRI, and MR angiography would help to locate hemangiomas of carotid sheath, but only surgical excision and histopathology can reveal their true nature.

Multi-detector row CT of the head and neck: comparison of different volumes of contrast material with and without a saline chaser

INTRODUCTION

The aim of this study was to determine the effect of different volumes of contrast material with and without a saline chaser on tissue enhancement in multidetector row CT (MDCT) of the head and neck.

METHODS

In a blind prospective fashion, 120 patients were randomized into the following four groups: group 1, 80 ml contrast material administered at a flow rate of 2.0 ml/s; group 2, 80 ml followed by 40 ml saline at 2.0 ml/s; group 3, 60 ml at 1.5 ml/s; and group 4, 60 ml followed by 30 ml saline at 1.5 ml/s. The attenuation values of the carotid artery, internal jugular vein, and muscle were measured at an interval of 1.5 s in each patient. The degree of perivenous artifacts was subjectively assessed.

RESULTS

Mean attenuation values in the carotid artery and internal jugular vein were significantly higher in groups 1 and 2 than in groups 3 and 4. The width of the diagnostic window (both carotid and jugular enhancement >150 HU) were significantly longer in groups 1 and 2 than in groups 3 and 4. The addition of a saline chaser did not result in improved vascular enhancement or a wider diagnostic window, but reduced perivenous artifacts, compared with using contrast material alone.

CONCLUSION

Reduction of contrast material from 80 to 60 ml results in insufficient enhancement of neck vessels. In addition, the benefit of a saline chaser technique is not obvious except for its ability to reduce perivenous artifacts.

Optimization of CT Angiography of the Carotid Artery with a 16-MDCT Scanner: Craniocaudal Scan Direction Reduces Contrast Material-Related Perivenous Artifacts

OBJECTIVE

The objective of our study was to compare the effect of a caudocranial scan direction versus a craniocaudal scan direction on arterial enhancement and perivenous artifacts in 16-MDCT angiography of the supraaortic arteries.

SUBJECTS AND METHODS

Eighty consecutive patients (51 men; mean age, 62 years; age range, 28-89 years) underwent scanning in the caudocranial direction (group 1; n = 40) or the craniocaudal direction (group 2; n = 40). All patients received 80 mL of contrast material followed by a 40-mL saline chaser bolus, both administered IV at 4 mL/sec. Bolus tracking was used. Attenuation inside the arterial lumen was measured at intervals of 1 sec throughout the data set. Attenuation in the superior vena cava (SVC) was measured. Contrast material-related perivenous artifacts were graded on a scale of 0-3 (none to extensive).

RESULTS

Attenuation in the ascending aorta, carotid bifurcation, and intracranial arteries was slightly lower in group 2 versus group 1 (231 +/- 64 H, 348 +/- 52 H, and 258 +/- 48 H vs 282 +/- 43 H, 381 +/- 73 H, and 291 +/- 77 H, respectively; p < 0.05). Maximum and mean arterial attenuations were slightly lower in group 2 versus group 1 (369 +/- 58 H and 303 +/- 48 H vs 401 +/- 71 H and 334 +/- 58 H; p < 0.05). Attenuation in the SVC was much lower in group 2 versus group 1 (169 +/- 39 H vs 783 +/- 330 H; p < 0.001). Mean streak artifact score was much lower in group 2 versus group 1 (1.3 +/- 0.9 vs 2.5 +/- 0.6; p < 0.001).

CONCLUSION

Use of a craniocaudal scan direction results in slightly lower attenuation of the carotid artery and much lower attenuation of the SVC. Streak artifacts are significantly reduced. This technique allows better evaluation of the ascending aorta and supraaortic arteries.

Lymph node pathology. Benign proliferative, lymphoma, and metastatic disease

The evaluation of cervical lymph nodes is one of the main indications for performing CT and MR imaging of the neck. Imaging may be done for evaluation of an unknown neck mass, but more commonly the neck is imaged to evaluate potential metastasis from a known mucosal malignancy. CT and MR imaging characteristics of both malignant and nonmalignant nodal diseases are reviewed and the differential diagnosis of nodal pathologies for specific imaging findings are discussed. A recently proposed imaging-based nodal classification for metastatic nodal diseases from head and neck cancer is also described.