[Diagnostic value of isocount scanning in cerebrovascular diseases (author's transl)]

In the previous report the theoretical background and technical details of the isocount scanning were described. Based on clinical experiences of various brain diseases, the newly developed scanning method was confirmed to be more useful than the conventional scintiscanning. Besides the new scanning method, a new display system was also developed for the sake of more precise analysis of the isocount scanned data. This display method is called multilevel analysis or multilevel slicing of the scanned data. In the present investigation, this method was applied to thirty-two cases of cerebrovascular diseases, including seven cases of cerebral arterio-venous malformation, four cases of hypertensive intracerebral hemorrhage and twenty-one cases of cerebral infarction, positive rates being 86%, 100% and 90% respectively. In case of arterio-venous malformation, minimum size detected by the isocount method was 2 cm in diameter. To twenty one cases of the cerebral infarction, total thirty two scanning examinations were performed, including postictal follow up studies. It is often said that it is two or three weeks after the ictus when the infarcted cerebral lesion is most clearly detectable by the scintigraphic procedures, presumably due to focal neovascularizations which may occur in the lesion most prominently at this postictal stage. Contradicted to the current concept, our experiences show that abnormal dot accumulations are recognized in the scintigrams even at the earlier stage, thus among five cases of cerebral infarction scanned within a week after the ictus positive figures were obtained in four cases, two of which were examined within two days after the ictus. Focal breakdown of blood brain barrier at the acute stage is considered to be responsible for the early positivity in cerebral infarctions. In eight cases among twenty one cerebral infarctions angiographies failed to demonstrate the vessel occluded. The isocount scanning method, however, succeeded in getting positive results in seven of the eight cases. It will be emphasized that the isocount scanning is a preferable diagnostic procedure in the cerebrovascular diseases, especially when the angiography is hesitated to be performed because of the patient severely affected.