Hypervascularity

Fig. 6.14 FNH Hypervascularized internal structure with hyperechoic star-shaped scar (= wheele-spoke pattern)...

Liver metastases are frequently multiple. They vary in size and are usually hypodense. In contrast to liver parenchyma, they display relatively sharp contours, with a difference in density of at least 10 -15 HU. In fatty liver, metastases may even appear hyperdense. Liver metastases are mainly supplied by arterial blood. Therefore i.v. (or even intra-arterial) bolus injection of CM produces the best diagnosis the metastasis shows increased CM enrichment during the short hypervascular phase additionally, a peripheral margin forms as a result of the increased concentration of CM. Metastases of 5 -10 mm can be detected. Data in the literature confirm a sensitivity of 65-91% (in breast cancer up to 100%) and a specificity of 81 - 92% with a success rate of 80 - 85%. Proof of metastases clearly depends on the histology of the primary tumour the best diagnostic results are obtained in breast and colon carcinomas. (22,39,50,53,57)... 

Fig. 8.11 Arterioportography coeliacography with good visualization of the branches of the coeliac trunk including the fine ramifications. Small hypervascularized haemangioma ( ) S = spleen. (The pancreatic vessels are also visible.) Normal depiction of the portal vessels in the venous phase...

Secondary malignant liver tumours, such as metastases of adenocarcinomas, are also hypovascular and therefore usually not identifiable by arteriography. In contrast, the metastases of malignant goitre, hypernephroid carcinoma, insulinoma and chorionepithelioma are hypervascular and therefore readily visible. 

In 80-90% of cases, focal nodular hyperplasia shows a typical, radial (spoke-like) arrangement of coiled vessels in the area of the tumour, which originate from a circular artery. Occasionally, fine a.v. shunts are present. The smooth-edged lesion is hypervascular. The parenchymal phase, with its homogeneous concentration of contrast medium, allows the lesion to be clearly demarcated from healthy liver tissue. (156) Hepatic adenoma is generally hypervascular. Displaced vessels are frequently visible. 

M. Hypervascular hepatocellular carcinoma detection with double arterial phase multi-detector row helical CT. Radiology 2001 218 763-767... 

Mahfonz, A.-E., Hamm, B., Taupitz, M., Wolf, K.-J. Hypervascular hver lesions differentiation of focal nodular hyperplasia from malignant tumors with dynamic gadolinum-enhanced MR imaging. Radiology 1993 186 133-138... 

FNH is the second most frequent benign hepatic tumour. It is a pseudotumorous regenerative node, most frequently occurring in women. Four-phase cholescintigra-phy using Tc-IDA is currently the best method of detection. In 80-90% of cases, perfusion is good with hypervascular tumours of > 2—3 cm in diameter. This results in initial enhancement of the FNH. However, the... 

These foci result from porphyrin deposition and are often only discovered by chance since there is no evidence of a chronic porphyria. They can be mistaken for tumours or metastases neither the foci nor their neighbouring parenchyma are hypervascularized. Following abstinence of alcohol and avoidance of oestrogens, they are completely reversible. In a chronic porphyria, there is frequently a uniform increase in density due to diffuse porphyrin storage. 

Fig. 34.6 Chronic necrotizing hepatitis B marked postnecrotic cleft formation in the area of the left lobe of liver (10 months after severe, acute necrotic hepatitis). Brownish to brick-red colouring of the liver with a flat, undulatory surface, scarry indentations and proliferation of connective tissue as well as spots of capsular fibrosis. Fine hypervascular arteries, pronounced venous contours and isolated lymph vessel congestion...

Magnetic resonance imaging may provide additional differentiation of unclarified findings - particularly in the diagnosis of haemangioma. Hypovascular lesions are detected more easily with SPIO-enhanced MRI, whereas detection and characterization of hypervascular lesions are improved with gadolinium-enhanced MRI. (8,14) (s. tab. 36.3)... 

To date, there has only been one single observation of a chondroma. (124) This tumour was excessively large (19 X 15 X 9.5 cm) it was hypervascularized, had a multilobular structure and did not possess a capsule. Focal calcifications were detectable. Chondrocyte-like cells and a chondroid matrix were found. Such a tumour can be visualized by imaging procedures. Laparoscopically, a hard, nodular surface is detectable. Diagnosis can only be confirmed histologically. 

Fig. 37.6 HCC nodiilar liver surface in cirrhosis. Tumour formation in the right lobe of hver, in parts at the margin central hypo-density with peripheral hypervascularization (CT after CM)...

Percutaneous fine-needle biopsy This technique is associated with the risk of tumour cell spreading. The frequency of subcutaneous implantation metastases is reported to be 2% they generally appear within 3 months. When this procedure is indicated, the bleeding risk from the usually hypervascularized tumour must also be taken into account. The cytologic-diagnostic sensitivity is 80-85% of cases specificity is 97-100%. (31-33, 128)... 

Ohnishi, K., Yoshioka, H., Kosaka, K., Toshima, K., Nishiyama, J., Kameda, C., Ito, S., Fujiwara, K. Treatment of hypervascular small hepatocellular carcinoma with ultrasound-guided percutaneous acetic acid injection comparison with segmental transcatheter arterial embolization. Amer. J. Gastroenterol. 1996 91 2574-2579... 

The first two changes make the third more clearly visible through the transparent skin. Within a few weeks or months, the restructured epidermis will cover up the hypervascularization, which tends to gradually diminish. 

Hemangioblastoma Multivacuolated stromal cells between many capillaries hypervascularity (fibrillarity is frozen section artifact) CD31 (S) factor VIII (S) NSE (S) Cerebellum spinal cord CNS... 

Fig. 3.2. Axial and coronal sections in the early arterial phase (left), late arterial phase middle) and portal venous phase (right) in a female patient suffering from hepatocellular carcinoma (HCC) under treatment with transarterial chemoembo-lization (TACE). In the early arterial phase only the liver arteries are properly enhanced the portal vein and also the liver parenchyma are not yet opacified. The two HCC nodules in segment 2/3 and segment 6 (marked by large arrows) are also both not properly demarcated. The early arterial phase, therefore, is not suitable for detection of hypervascular tumors it is rather a CT angiographic phase and can be omitted in most cases. The most important phase for detection of hypervascular tumors is the late-arterial phase (also called arterial-dominant phase or phase of portal venous inflow). In this phase there is already enhancement in the portal-vein (small arrow in the upper row) and in the liver parenchyma. The liver veins are not yet opacified in this phase (small arrow in the lower row). Most hypervascular tumors reach their highest attenuation in this phase. In the portal venous phase enhancement of the liver parenchyma is highest, the vascular enhancement in the portal venous system and in the hepatic vein is similar. Hypervascular tumors show decreased attenuation compared to the late-arterial phase depending on the degree of wash-out they can be still hyperdense (as in this case), isodense (see Fig. 3.4) or even hypodense...

---