Arterial spin labeling MR imaging of head and neck squamous cell carcinoma Abdel Razek A Department of Radiology Mansoura Faculty of medicine. Mansoura. Egypt

Introduction Head and neck cancer is a significant cause of world wide morbidity and mortality. Prognostic factors of head and neck squamous cell carcinoma (HNSCC) are histological grade, tu,or stage and nodal status. These parameters well correlated with recurrence and overall survival.

Arterial spin labeling (ASL) perfusion MR imaging involves repetitive serial imaging through the tumor with an endogenous magnetic tracer label. ASL has been used in neuroimaging and in different regions of the body such as lung. Recently, ASL has been used in head and neck region.

Aim of the work To evaluate the role of arterial spin labeling (ASL) in head and neck squamous cell carcinoma (HNSCC).

Patients: Institutional board approval was obtained Informed consents from patients was taken Prospective study was done upon 37 consecutive patients with HNSCC (23M, 14F aged ys: mean 49ys). They presented with neck mass, dysphagia, and hoarseness of voice Patients and methods

Methods of examinations: Routine MR (T1,T2WI). ASL images of head and neck. Routine post contrast T1WI. Histopathological examination.

MR Machine: 1.5 tesla MR unit (Ingenia Philips Nederland) Gradient strength: 30mTm. slew rate: 120 T/m/s. Routine pre contrast: T1-TSE (TR/TE=650/15ms) and T2-TSE (TR/TE=5000 /130 ms) with SENSE Section thickness= 6 mm and inter slice gap=0.6mm, FOV= mm & matrix=256x224.

ASL Perfusion sequence: Multi-phases arterial spin labeling with FEEPI sequence Labeling plane: Labeling plane located at level of common carotid artery just under bifurcation of internal and external carotid arteries

Scanning parameters: TR = 250 ms, TE =20 ms, flip angle =35degress, slice thickness = 6 mm, interslice gap=0.6 mm, NEX=1, FOV=25 cm X 20 cm, dynamic repetition for 30 SENSE factor=2.5 and scanning time=4 minutes and 8 seconds. There was reconstruction of 2880 source images Instruction during acquisition The patients instructed not to swallow, move their tongues, open their mouths, or make any other voluntary motion during scan. Heads were fixed firmly with coil to prevent movement during scan.

Post processing: Subtraction of images with reconstruction of 48 serial images. Arterial input selection of internal carotid artery as reference. Reconstruction of parametric images.

Image analysis: Image analysis was perfumed by one radiologist ASL: ROI was placed around the tumor with calculation of T BF

Pathological examination: Surgery or biopsy was done for all patients. Pathological type: Degree of differentiation of malignancy was done. Malignancy was classified as well, moderately and poorly and undifferentiated malignancy

Mean & SD: Mean & SD of TBF of HNSCC. T test: Significant difference in TBF between degree of differentiation, grading, staging and presence of cervical lymphadenopathy. P value <0.05 considered significant ROC curve: to select cut off point of TBF used to differentiate grading, staging and presence of cervical lymph nodes Statistical analysis

RESULTS Location of HNSCC Locationnumber Oral cavity Oropharynx Hypopharynx Larynx

TBF of differenaiation of HNSCC Degree of dfferentiationTBF Well and moderately differentiated Poorly and undifferentiated ± ±5.7 P value0.001

ROC of TBF for degree of differneiation ROC Cutoff point AUC Accuracy %

TBF of staging of HNSCC GradingTBF Stage I, II Stage III & IV ± ±9.3 P value 0.014

ROC of TBF of staging Parameter Cutoff point AUC Accuracy %

TBF of nodal of HNSCC Nodal statusTBF Present Absent ± ±9.8 P value0.044

ROC of TBF of nodal assessment Parameter Cutoff point AUC Accuracy %

Conclusion We concluded that ASL is a non-invasive imaging technique that can predict stage, degree of differentiation and metastatic cervical lymph nodes in patients with HNSCC.