Normalization of thyroid blood flow in Graves' hyperthyroidism following radioactive iodine therapy.

In a group of 12 patients with Graves' hyperthyroidism, administration of 514 +/- 43 (mean +/- SD) MBq iodine-131 was associated with a fall of superior thyroid artery (STA) blood flow in two at 6 months and in eight at 11 months. The reduction in time-averaged velocity at 11 months correlated with the reduction in FT4 (r = 0.72, P less than 0.01) and in FT3 (r = 0.64, P less than 0.025) at this time. In four patients who had persistent elevated STA blood flow, two were still hyperthyroid. The diameter of the STA was unchanged at 6 months and only half the patients had reduction of their STA size at 11 months after radioiodine (RAI) therapy. These data indicate that normalization of STA blood flow precedes normalization of STA size in patients treated with RAI. Further work is required to determine whether STA blood flow measurements are of predictive value in treatment outcome.

Neovascularization in human cutaneous melanoma: a quantitative morphological and Doppler ultrasound study.

A study of tumour blood flow in 36 patients with 38 malignant melanomas using Doppler Ultrasound flowmetry has shown that tumour blood flow can be detected in most melanomas more than 0.9 mm thick, and is absent in most melanomas less than this thickness. Histological quantitation of blood vessels using lectin staining to delineate vascular endothelium and automated image analysis has shown a high degree of correlation between vascularity at the tumour base and tumour thickness. Since it is likely that the development of a vascular plexus at the tumour base is a prerequisite for dissemination, the development of these blood vessels may prove to be an independent prognostic factor for thin melanomas. This work also provides a new model for dynamic, in vivo investigation of the vascularity of human tumours.

The significance of blood flow in cutaneous malignant melanoma demonstrated by Doppler flowmetry.

The vascularity of malignant melanoma has been studied in 23 patients by Doppler ultrasonic frequency shift recordings. A 10 or 8 MHz directional Doppler probe was used and the signals were analysed on an Angioscan II spectrum analyser. No blood flow was detected in 7 primary melanomas each of thickness less than 0.75 mm and one recurrent subcutaneous nodule. Abnormal blood flow signals were detected in 8 primary melanomas--each of thickness greater than 1.2 mm--and in 7 skin nodules of secondary melanoma. Three tumours did not conform to the general pattern--one primary tumour 0.7 mm thick had abnormal blood flow signals whereas one primary lesion of 2 mm thickness and one secondary deposit were flow negative. Thus neovascularization corresponds in general to the cut-off point for good prognostic tumours, suggesting that it is a development of biological significance. This vascular pattern can be detected non-invasively by means of a Doppler probe and may have a prognostic importance, particularly with melanomas of the intermediate thickness range of 0.75-3.0 mm, where precise outcome cannot at present be predicted. The significance of an abnormal blood flow in one thin tumour remains to be determined from long-term follow-up.

Duplex scanning of the thyroid.

High resolution ultrasound scanners are used to image nodular thyroid glands and in the study of thyroid malignancy. There are no specific ultrasonic characteristics of malignant lesions to distinguish them from benign conditions. Preliminary results using a Duplex ultrasound scanner shows that the detection of a high frequency Doppler-shift signal from the superior thyroid artery is indicative of an overactive thyroid. In a study of 23 consecutive patients who were being investigated for possible hyperthyroidism, 15 were found to have normal thyroid function and 8 to be overactive. The normals had a mean systolic peak frequency of 1.77 +/- 1.75 kHz, and the hyperthyroid group 4.08 +/- 1.5 kHz. This result is highly significant, having a p value less than 0.0002 (Mann-Whitney U Test). In another 10 patients with solid lesions, one was diagnosed as follicular carcinoma. High frequency Doppler shift signals, similar to those found in carcinoma of the breast, were detected in the periphery of the lesion but were not found in nine cases of adenoma. Duplex scanning may assist in the investigation of hyperthyroidism and in the differential diagnosis of benign and malignant lesions.

Correlation of clinical findings, duplex carotid artery scanning and CT scanning of the brain in 54 consecutive patients with bruits over the carotid artery bifurcation.

Fifty-four patients presenting consecutively with bruits over the carotid artery bifurcation have been studied by Duplex ultrasonography of the carotid artery and CT of the brain. The patients were divided into symptomatic (transient ischaemic attacks (TIA), non-focal neurological symptoms, minor and major strokes) and asymptomatic groups. The duplex scans were subdivided into those showing a greater than 50% stenosis of the internal carotid artery and those with a less than 50% stenosis. The CT brain scans were subdivided into those showing evidence of cerebral infarction and those without. Symptomatic patients were found to be more likely to have an area of cerebral infarction than asymptomatic ones (P = 0.0086 Fisher's Exact Test). Patients with a significant stenosis (greater than 50%) of the internal carotid artery were more likely to have an ipsilateral cerebral infarction on CT than patients with a minor stenosis (less than 50% stenosis) (P = 0.028 Fisher's Exact Test). Three patients (two with TIA's and one with non-focal neurological symptoms) were found to have unsuspected cerebral infarcts on CT of the brain. These patients could theoretically be at risk following carotid endarterectomy and revascularization if the infarct were an early one. Patients with non-focal neurological symptoms and carotid bruit were more likely to have a significant stenosis than asymptomatic patients with carotid bruit (P = 0.0069 Fisher's Exact Test). Therapy should be directed at the carotid artery lesion in these cases. Duplex scanning of the carotid artery bifurcation may be combined usefully with CT brain scanning in the non-invasive investigation of patients with symptomatic extracranial carotid artery bruits.