Vascular Pattern in Tumours

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1 Acta Radiologica ISSN: (Print) (Online) Journal homepage: Vascular Pattern in Tumours To cite this article: (1957) Vascular Pattern in Tumours, Acta Radiologica, 47:sup151, , DOI: / To link to this article: Published online: 14 Dec Submit your article to this journal Article views: 27 Full Terms & Conditions of access and use can be found at

2 83 VASCULAR PATTERN IN TUMOURS The angiographic diagnosis of an intracranial tumour is based on two factors: the manner of growth and the vascular architecture. These give information not only about the site of the tumour but in many cases also concerning its nature. Some tumours expand and push away the adjacent brain tissue, causing considerable displacement of the vessels. Others have a more infiltrating growth around the vessels, altering their normal winding courses and smooth curves and giving them a stretched appearance. This is of some value in determining the nature of the growth inasmuch as it helps us to distinguish between extracerebral and intracerebral tumours. The angiographic determination of the pathology of the tumour is, however, mainly based on the other factor, i. e. the vascularization of the tumour. Many tumours have a vascular architecture which differs from the normal brain tissue. Some are highly vascularized while others are poor in vessels as compared to the surrounding tissues. Malignant tumours, particularly, undergo degenerative changes and thus contain necrotic areas, cysts, or haemorrhages. The types of tumour which are most frequently supplied with pathologic vessels are the glioblastomas, meningiomas, metastases, and haemangioblastomas. Glioblastornas. The vessels occurring in glioblastomas have varying angiographic appearances and are therefore often divided into several groups. I have found that any practical advantage can only be gained from a classification of the hypervascularized glioblastomas into two groups. Group I. To this group are referred tumours that are generally highly vascularized and contain numerous vessels pursuing an irregular course. The lumen is uneven and there are usually many direct connections

3 84 Fig Glioblastoma, highly vascularized. Pathologic connections between arteries and veins. A drainage vein already filled in the arterial phase. between the arteries and veins. In exceptional cases a few vessels may display the appearances just described and there may be only a few pathologic connections between the arteries and veins. At angiography the contrast-filled veins are usually seen in the arterial phase (Fig. 105), but when the number of pathologic connections is great the contrast medium passes rapidly through the tumour and may sometimes have disappeared completely from it in the venous phase. It may be very difficult in such a case to distinguish between a tumour and an arteriovenous malformation. The feeding arteries and the drainage veins are generally much more dilated in an arteriovenous malformation. A tumour is usually more expanding. If there is an intracerebral haematoma in connection with the malformation it may be impossible in isolated cases to obtain a definite diagnosis before operation. A case of a small arteriovenous malformation with an intracranial haemorrhage is shown in Fig The feeding artery is slightly widened; a glioblastoma could cause such a widening of the feeding artery but then the tumour would be richer in vessels, and the pathologic connections between the arteries and veins would be more numerous. In other glioblastomas the contrast medium may pass rapidly through the arteries but remain for a long time in the veins. These may be seen filled after other parts of the brain have emptied, due probably

4 85 a Fig Arteriovenous malformation with an intracranial haemorrhage. a) Lateral view. Widened feeding artery from the callosomarginal artery. b) Slight local displacement of pericallosal and callosomarginal arteries to the left (+). Malformation +. b to oedema in and around the tumour. In about a third of our cases of glioblastoma vascular changes of the type described have been found. The three films shown in Fig. 107 are from a rapid serial angiography at 2 films per sec. In the first film only a very few pathologic vessels are filled; in the second, numerous small arteries are seen but no definite veins. The third film represents a late arterial phase and several small drainage veins are filled. The diagnosis of pathologic connections between the arteries and veins could be arrived at only from this last film. In the subsequent films the contrast medium had disappeared from the arteries. If a routine examination with only three films had been made, it is very likely that the pathologic connections could not have been demonstrated. A study of the drainage conditions of the tumour also affords valuable information for an estimate of its extension. Contrast filling of veins in the arterial phase may be observed not only in cases of glioblastoma and arteriovenous malformations but also in the so-called malignant meningiomas. We have observed only a few such cases but in all of them the tumour obtained a part of its blood supply from the external carotid artery, which never happens with

5 86 Fig Rapid serial angiography: 2 films per second. Only in the bottom view are definite pathologic connections between arteries and veins visible.

6 87 Fig Hypervascularized zone around a necrotic cyst in a glioblastoma. glioblastomas. Furthermore, in cases of malignant meningioma the vessels seem to be more regular. Group II. The tumours in this group have vessels of similar appearance to those in Group I but pathologic connections between the arteries and veins are not present to a degree to enable contrast-filled veins to be seen in the arterial phase. The frequency of tumours included in this group will probably in future become lower when rapid serial angiography comes into increasing use.

7 88 When dividing the hypervascularized glioblastomas into only two groups, tumours with all degrees of vascularization, even those with only a few pathologic vessels, will inevitably be included in the second group. All of them, however, will have vascular irregularity as a common feature. If the vessels are few, and there is no marked irregularity, it may be difficult to distinguish between tumour vessels and fragmentarily filled normal vessels. From a practical point of view, the characteristic changes of Group I may be said to be pathognomonic of glioblastoma, which cannot be said of Group 11. The vascular architecture characteristic of this group is not specific for any type of tumour. It may occur in glioblastomas as well as in other types of gliomas, and with metastases. The vessels may sometimes be very difficult to differentiate from those in meningiomas, although the latter usually have a more regular arrangement. Haemorrhages, necroses, and cysts, are often present with glioblastoma, and these will influence the angiographic picture. There are no vessels in such affected regions but the lesions are very often surrounded by a more or less ring-shaped hypervascularized zone. This zone may sometimes be visible in the arterial phase (Fig. 108) although changes of this kind are generally best seen in the venous phase. They may occur in both groups. But an avascular area surrounded by a highly vascular zone is not pathognomonic of glioblastoma. Similar changes occur also with other types of glioma, as well as with metastases; in our experience, however, they rarely seem to be found except in cases of glioblastoma and metastases. A vascularized zone may also often be seen around an abscess, but the vessels then have no irregular lumina and appear as normal brain vessels. We are now left with two other types of glioblastomas, one including those in which the tumour area is poorer in vessels than its surroundings, and the other, those in which no change in the architecture of the vessels can be demonstrated. A tumour may thus be poor in vessels or have an apparently normal vascular architecture and yet the possibility of a glioblastoma cannot be excluded. Meniizgiornas. The vascular architecture in meningiomas is more regular than in glioblastomas. Pathologic vessels were present in about 50 yo of the cases in our material. A typical feature of the vessels in glioblastomas is that the lumen is irregular, whereas in meningiomas the newly-formed vessels have regular lumina but pursue a twisted or serpentine-like course. The most common type is characterized by a

8 89 a Fig Meningioma. a) Lateralview. b) Frontal view. The vessels in the periphery of the tumour are filled from the internal carotid artery. b a b Fig Same case as infig a) Lateral view. b) Frontal view. The centre of the tumour is filled-from the external carotid artery.

9 90 b Fig Meningioma growing through the bone a) The tumour is partly vascularized from a superficial vessel. b) Soft tissue view to show the vessels in the part of the tumour lying outside the vault. a great abundance of capillaries. We have seldom encountered tumours appearing as a homogeneous density. In many cases, the tumour vessels become filled with contrast medium as early as the arterial phase and this filling continues into the venous phase. In some cases, the vessels may be seen only in a late phase, and when this happens there are either no pathologic vessels at all visible in the arterial phase, or only a few thin and regularly arranged arteries may be observed. Meningiomas often receive their vascular supply both from the internal and the external carotid arteries. If the contrast medium is injected into one of these arteries only the part of the tumour supplied from that artery will become filled with the medium, and this will influence the appearance of the tumour in the film. We have found that the periphery of the tumour is often vascularized from the internal carotid artery (Fig. 109) and the central part from the external carotid (Fig. 110). After injection into the internal carotid artery the appearances may suggest a necrotic or cystic area surrounded by a highly vascular-

10 91 Pig Tangle of vessels in intraventricular meningioma. ized zone, as in some cases of glioblastoma. However, in meningioma the peripheral vessels have a much more regular appearance, the tumour is well outlined, and the vessels in the empty area become filled after injection into the external or the comn on carotid artery. Another type of vascular change in meningioma is represented by cases with narrow regular tangled vessels or with vessels arranged in a radial fashion suggesting a wheel. This type of vascularization seems to be most common with intraventricular meningioma (Fig. 112) and meningioma in the cerebellopontine angle. The opinion has been expressed that if a tumour is vascularized from a dilated anterior choroid artery it is certain to be an intraventricular meningioma; this, however, is not correct. Any hypervascularized tumour in this region, if fed from this artery, may cause a slight widening of its lumen. A further type of change is represented by cases with a few small newly-formed vessels with no characteristic appearances. If it can be shown that such vessels become contrast filled upon injection into the external carotid artery the diagnosis of meningioma can be made with some confidence (Fig. 113). A rather wide artery is often seen encircling a tumour and in such a case there is probably a, meningioma even if no other vascular changes can be demonstrated (Fig. 114). Metastases and gliomas may sometimes be seen surrounded by vessels but these are usually veins and not arteries. Moreover, the more or less complete circle is then usually formed by several small vessels. 7-5i324 2

11 92 Fig Meningioma. Small vessels of uncharacteristic appearance, filled from the external carotid artery.

12 93 Fig A wide artery encircling a meningioma. Fig Atypical vascular architecture of a meningioma.

13 94 Fig Accumulation of contrast medium in a metastasis. The tumour is not as dense as a meningioma. In exceptional cases, the vessels in a meningioma may be rather wide and lack the common regular appearance, and the tumour may be more like a glioblastoma (Fig. 115). A meningioma, however, is usually richer in vessels than a glioblastoma and is also more sharply outlined than is characteristic of tumours of the latter type. The differential diagnosis in such cases may sometimes be difficult. Metastases. It has been stated that a homogeneous contrast filling of a tumour is pathognomic of meningiorna, but this is unfortunately not true. An accumulation of contrast medium may occur in metastases but the outlines of the lesion are then generally more irregular, and the filling is not so dense (Fig. 116); the tumour when diagnosed is usually smaller. If multiple tumours are observed (Pig. 117) the presence of metastases is more probable, although of course meningiomas may also be multiple. If the tumour can be shown to lie intracerebrally the possibility of meningioma may practically be excluded.

14 95 Fig Multiple metastases. Metastases quite frequently in our material - in about 50 yo of the cases - were rich in vessels. In a consecutive series of 38 cases, there were 6 with vascular changes of such a nature that it was not possible from these alone to differentiate the tumour from a meningioma. With some metastases the vascular changes resemble those found in glioblastomas included in Group I1 and mentioned in the previous

15 96 Fig Metastasis. Irregular pathologic vessels similar to those in glioblastomata. section (Fig. 118). It is then not possible to draw any definite conclusions regarding the nature of the tumour from the appearance of the tumour vessels alone. Growths with changes of this type are usually glioblastomas or metastases. Such changes appear to be common with metastases from hypernephromas, and the more or less homogeneous accumulation of contrast medium seems to be more common with metastases from carcinomas. GZiomas other than glioblastomas are usually less vascular, and definite tumour vessels are comparatively seldom observed. When they do occur, their appearance is generally atypical. We have found pathologic vessels with astrocytomas in about 4 yo of the cases in our material. They are sometimes best seen in the arterial phase and at others in the venous phase; the vessels are usually short and small and only slightly irregular. We have recently commenced a study of the circulation time by means of rapid serial angiography. By circulation time through the brain we mean the period from maximum filling of the carotid siphon to maximum filling of the parietal veins; by circulation time through the tumour is meant the period from maximum filling of the carotid siphon to maximum

16 97 Fig Fine regular vessels in a papilloma. filling of a drainage vein. So far, we have made only comparatively few examinations of this kind. As may be seen from Table I, the circulation time through meningioma is in all cases longer than the circulation time through the brain, while the opposite is valid for gliomas and metastases. We expect much from this method of determining the nature of a tumour, since as far as Glioblastomas Astrocytomas Table I. Circulation time through T!k?.f Brain... 2,4 3,l 3,2-2,O - 2, ,8 6,2... 4, ,9 6,5 7,5 Oligodendrogliomas... 3,3 h,l Metastases... 3,5 2, ,l 5,8 Meningiomas ,5 10,5 5,6 6,O Central, not verified ,3-2,8 7,3 5,l 8,3 6,O 2,8-2,3-5,l 5,7 8,5-9,0-5,6 5, ,3-3,8-4,8 4,8 49-5,O

17 98 Fig Haemangioblastoma. The solid tumour consists of a tangle of small regular vessels. we are able to judge the same circulatory conditions hold also for tumours which from the films do not appear to be hypervascularized. Among the data recorded in the table are 7 cases of tumour in which pathologic tumour vessels were absent. Papillomas are occasionally rich in vessels. The few cases we have observed have had fine, fairly regular vessels of the type shown in Fig Haemangioblastomas of the cerebellum are as a rule small, well outlined, and localized to the cortical or subcortical layer of the ventral or dorsal part of the cerebellum. They are never found in the anterior middle region. In most cases they are cystic, the solid tumour mass being situated close to the outer wall of the cyst; in rare cases the cyst wall may consist of the tumour proper. In our experience, vascular changes are present in nearly all haemangioblastomas. In cases of the first-mentioned type, the solid tumour consists of a tangle of small vessels with regular lumina (Fig. 120). They thus resemble vessels found in meningiomas. The tumour vessels are in some cases best seen in a late arterial or in the venous phase. The size of the solid tumour mass is evident from the films but the size of the cyst must be judged from the displacement of the surrounding

18 99 Fig Multiple haemangiolnlastomas. Fig Haemangioblastoma. The angioma forms the wall of the cyst.

19 100 vessels. This vascular displacement is often slight, even in the presence of large cysts. Haemangioblastomas are frequently multiple. In the case represented in Fig. 121 a tumour had been removed at operation some yearsbefore the examination which showed the presence of several tumours. In another type of haemangioblastoma, the cyst wall is formed by the actual angioma (Fig. 122). The angiographic appearance of such a lesion is a ring of tortuous vessels surrounding an avascular area. The true size of the tumour is evident from the films. When recurrence is suspected we start the investigation with vertebral angiography since encephalography may be difficult to perform and interpret due to the postoperatively altered structures in the posterior fossa. If the tumour is rich in vessels a definite diagnosis may be obtained by means of the angiographic examination.