Arto Sivula

Nuclear magnetic resonance (NMR) imaging of intracerebral hemorrhage in the acute and resolving phases.

Nuclear magnetic resonance imaging of intracerebral hemorrhage revealed a considerable difference in the appearance of the bleedings in the acute and resolving phases. Attention is drawn to the shortening of the relaxation time T1 within the first 2 weeks after the acute onset of symptoms with the location of the change at the periphery of the lesion. The change was most evident with T1 dependent inversion recovery sequence (IR1,500/400). With this pulse scheme the acute hemorrhage was visualized as a dark area during its early days. A bright zone, reflecting the shorter T1, was not seen until the resolving phase at the end of the 1st week. Although its pathophysiological aspects are so far unknown, this finding may offer an opportunity for dating intracerebral hemorrhages.

Natural History of Treated Primary Hyperparathyroidism

A follow-up study of patients operated on for primary hyperparathyroidism revealed that recurrent hypercalcemia is uncommon in patients with solitary adenoma, but common in patients with multiglandular disease. The result of parathyroidectomy on the different symptoms of primary hyperparathyroidism is good. On the other hand, even after successful surgery, patients with primary hyperparathyroidism have poorer health than controls, and they also have a higher mortality rate. Most of the deaths in the primary hyperparathyroidism group are caused by cardiovascular disease. The effect of the preoperative serum calcium level on the later state of health is evident.

Low field (0.02 T) nuclear magnetic resonance imaging of the brain.

Many technical and instrumental alternatives are available to obtain good spatial and contrast resolution in magnetic resonance (MR) imaging. Optimum field strength remains a controversial question. In spite of its inherent low signal-to-noise ratio, low field imaging exhibits some advantages. It is well established that the relaxation times are dependent on the magnetic field strength. In low fields the relaxation times, especially T1, are shorter and the relative differences of T1 between different tissues are larger. Other benefits are the ease of installation of the device, its cost effectiveness, and the obvious avoidance of hazards caused by the magnetic field. In this report we describe six cases of cerebral lesions studied with an MR imager operating at a field strength of 0.02 T (200 G). This is the lowest field strength reported in clinical MR imaging. The information obtained was equal to that of the CT studies performed on the same patients.

Intracranial hematomas studied by MR imaging at 0.17 and 0.02 T

The contrast in magnetic resonance (MR) images relies mainly on the relaxation time differences between the tissues. The relative differences in relaxation times T1 are bigger at lower field strengths, although the absolute values of T1 are smaller. A shorter T1 is also advantageous for the contrast of the T2 and proton density weighted images because of the more complete recovery of the spin system during the repetition time TR. Scrutiny of the clinical results of MR shows some unsolved problems in the specificity of diagnosing fresh intracranial hematomas. Low field MR imaging at 0.02 T seems to offer new vistas in this sense. Fresh subdural hematoma was more easily detected and differentiated at 0.02 T than at 0.17 T. The T2 of fresh intracranial hematomas was rather short compared with cerebrospinal fluid and edema and, unlike T1, was not highly dependent on magnetic field strength. The different visualization of acute versus late intracerebral hematoma and the changes during the resorption were demonstrated in follow-up studies of two patients at 0.17 T and of one at 0.02 T. In one patient the same lesion was imaged successively at both field strengths, showing the divergent contrast in the inversion recovery images at 0.02 and 0.17 T.

Long-term. Health Risk of Primary Hyperparathyroidism: The Effect of Surgery

Primary hyperparathyroidism is a common disease but 90% of sufferers remain undetected. In elderly women its prevalence is about 1%. The disease can cause severe hypercalcaemia and lead to life-threatening symptoms. However, the majority of cases represent milder forms of hyperparathyroidism with minimal symptoms or no symptoms at all, and slight hypercalcaemia which does not progress during follow-up. Surgery is the only effective treatment of primary hyperparathyroidism and most of the symptoms respond favourably to surgery. Nevertheless, the role of surgery has been controversial in the treatment of mini-symptomatic patients. Recently it has become evident that primary hyperparathyroidism is associated with increased mortality due mainly to cardiovascular diseases, and it has been shown that surgical treatment is able to diminish or even eliminate this risk of premature death. The extra mortality is connected also to the mild and nonprogressive forms of the disease, and it seems to have a strong correlation with the duration of the disease. This aspect favours active treatment at an early stage of the disease. Conservative treatment can be considered only in old patients with mild and stable clinical course. Primary hyperparathyroidism is an important risk factor causing morbidity and mortality.

Hypercalcemia: serum chloride and phosphate.

Excerpt To the editor: In the December 1976 issue Pak and Townsend (1) questioned the usefulness of the serum chloride/phosphate ratio in the diagnosis of primary hyperparathyroidism. Our experienc...

Detection of iodine, sulphur and phosphorus in histological thyroid sections by using electron probe microanalysis.

Electron probe microanalysis for iodine, sulphur and phosphorus was performed in histological frozen sections from thyroid tissue of 5 patients undergone thyroid surgery for benign disease. Iodine seemed to be localized in the colloid of the thyroid follicles. Phosphorus localized in areas which corresponded with the epithelium of the follicles. Sulphur showed a strong association with iodine both in localization and in relative amounts. It was suggested that iodine and sulphur reflect the presence of thyroglobulin in the colloid of thyroid follicles.