[The weighting of SE, IE and GE sequences in tumors of the head and neck].

In a review of 82 patients having different benign and malignant head and neck tumours we studied the value of spin echo (SE), inversion echo (IE) and gradient echo (GE) sequences. The strong T1 weighted IE mode is highly sensitive to demonstrate pathological tissue. Tumour diagnosis was in 20% and lymph node diagnosis in 29% better than T2 weighted SE sequences. According to this experience we choose the IE mode as the first one for all patients examined for tumour staging. All other sequences and orientations are planned on this tomograms knowing the location of the tumour and lymph nodes. T1 weighted SE mode is indispensable and should be recorded in transversal orientation, covering the whole head and neck region. This mode has the best imaging of anatomical structures as the known fatty limitations. The best differentiation of the tumour is usually obtained after contrast enhancement by i.v. Gd-DTPA. The highest contrast enhancement is seen on T1 weighted GE tomograms, which we prefer. T2 weighted SE sequences are less sensitive than IE sequences and T1 weighted tomograms after Gd-DTPA to show the tumour. The T2 weighted SE mode cannot be replaced by the T2 weighted GE mode having a better signal to noise ratio. To minimise the scan-time of T2 weighted SE mode, only one measurement is performed; the quality of the tomograms is satisfactory.