Joint Program in Nuclear Medicine

Imaging Workup of Hepatic Hemangiomas

Jac D. Scheiner, MD 
Kevin J. Donohoe, MD

September 10, 1996

Presentation

A 53 year old woman with a history of a messencymal tumor of the thigh presented with hepatomegally.

Imaging Findings

The ultrasound of the liver showed a hyperechoic mass in the dome of the right lobe (seen a sagital and an oblique images; arrows show lesions on sagital and on transverse images). In addition there was a complex lession at the inferior tip of the right lobe of the liver (shown by arrow). First past images from the blood pool study (above) show no areas of increased flow. Planar delayed images show two areas of increase uptake (the lesion in the dome of the right lobe corresponding to the hyperechoic lesion is shown by arrow heads; the lesion at the tip of the right lobe is shown by arrows; also seen are the blood pools of the heart, H, and the spleen, S). Coronal SPECT images show these two areas of increased blood pool.

Discussion

Hemangiomas are the most common benign tumor of the liver, noted in up to 7% of patients on autopsy series. Up to 20% are multiple. Histology demonstrates an overgrowth of enlarged endothelial lined vascular spaces. While almost always asymptomatic, these tumors have been associated with abdominal pain, fullness, and belching. Complications are similarly rare, but have included bleeding, infarction, necrosis, and thrombocytopenia. The clinical importance of these incidentally discovered tumors relates to distinguishing them from malignancies.

Among the most common imaging modalities used to evaluate hemangiomas are ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI) and technetium-99m labeled red blood cell single photon emission computed tomography (Tc-99m RBC SPECT).

Ultrasonography

The classic finding of hemangioma on US is that of a well defined, echogenic mass. This is seen in approximately 50-60% of hemangiomas (1). However, this appearance can also be seen in adenomas, hepatocellular carcinomas, and metastatic disease. The specificity of US findings for hemangioma is increased if one also sees increased through transmission, although this is not always seen. Stable finding over several US exams can be used to suggest the lesion is benign. In a study of 21 hemangiomas in 21 patients seen on US or CT, follow-up imaging in 5-84 months (mean = 26 months) demonstrated size stability in 90% (19/21) (2). Of the 2 that had increased in size, one had increased by 1 cm in 3 months and then remained stable at 3 year follow-up, while the other had increased by 2 cm in 10 months. In the latter case, the patient developed thrombocytopenia (an extremely rare complication) and the hemangioma was resected.

Computed Tomography

The classic finding of hemangioma on CT is that of a round, low attenuation lesion with slight lobulations on the non-contrast images. Following contrast injection, "peripheral puddling" of contrast (of an attenuation matching the aorta) is seen. The classic findings are not always evident, however. A study of 58 hemangiomas in 47 patients who prospectively underwent CT with and without contrast, using a more stringent criteria which required the lesion to have an attenuation greater than or equal to the liver on delayed images, demonstrated classic findings in only 55% (32/58) of the hemangiomas (3).

Tc-99m Labeled RBC SPECT

The classic findings of hemangioma on Tc-99m labeled RBC SPECT are a lesion that is undetectable or demonstrates decreased intensity compared to the liver on the flow images, and increased intensity to the liver on the 30-60 minute delayed images. These findings are nearly 100% specific for hemangioma. In the literature, there have been only 8 reported false positive cases of hemangioma (4-9). Two of these were cases of hepatocellular carcinoma in which there was increased tracer localization on the flow images. Another 2 were cases of hepatocellular carcinoma in patients with chronic liver disease. The remaining 4 were in cases of intrahepatic extramedullary hematopoiesis, metastatic gastric carcinoid, metatstatic colon cancer, and angiosarcoma. Of these 8 cases, only one (metastatic colon cancer) had characteristic hemangioma features (on both flow and delayed images) and could be considered a common tumor.

SPECT significantly improves the sensitivity for hemangioma detection over planar imaging, especially for lesions less than 5.0 cm. A study of 77 hemangiomas in which planar imaging and single head SPECT were performed showed the sensitivity of these 2 techniques for different size lesions to be as follows (10):
Size (cm)  Planar (%) SPECT (%) 
<=2.0 6/31 (19)  9/26 (35) 
2.1-3.0 12/21 (57)  16/19 (84) 
3.1-5.0 13/16 (81)  15/15 (100) 
>5.0 9/9 (100)  9/9 (100) 
Another study of 108 hemangiomas less than 5.0 cm, in which planar imaging and single head SPECT was performed, gave the following sensitivities (11):
Size (cm)  Planar (%) SPECT (%) 
<=1.0 0/20 (0)  0/20 (0) 
1.1-2.0 3/29 (10)  11/29 (38) 
2.1-3.0 15/35 (43)  29/35 (83) 
3.1-4.0 8/13 (62)  12/13 (92) 
4.1-5.0 10/11 (91)  11/11 (100) 
This same study also looked at 45 hepatocellular carcinomas sized 1.5-5.0 cm. None of these malignancies met the scintigraphic criteria for hemangioma.

Two headed SPECT study of 56 hemangiomas resulted in slightly improved sensitivities (13):
Size (cm)  Planar(%) SPECT1(%) SPECT2(%) 
<=1.0 1/11 (9) 2/11 (18) 9/11 (92) 
1.1-2.0 3/14 (21) 7/14 (50) 13/14 (93) 
2.1-3.0 6/11 (55) 9/11 (82) 11/11 (100) 
3.1-4.0 5/6 (83) 6/6 (100) 6/6 (100) 
>=4.1 14/14 (100) 14/14 (100) 14/14 (100) 
SPECT1 refers to conventional SPECT images, whereas SPECT2 refers to SPECT images interpreted on a 3-D digital display.

A study in which 3 headed SPECT was performed on 34 hemangiomas (0.5-6.8 cm, mean = 2.2 cm) gave the following sensitivity results (14):
Size (cm) SPECT (%) 
<=0.8 cm 1*/5 (20) 
0.9-1.3 cm 3/9 (33) 
>=1.4 cm 20/20 (100) 
* this was a 5 mm hemangioma 
False negative exams most commonly occur because of small hemangioma size. Other reported causes include the hemangioma being adjacent to a vascular structure (such as the heart, portal vein, or IVC) (13), perceived increased activity on the flow images (reported in 6% and 8% of cases in 2 studies) (10,15), and extensive fibrosis within the tumor itself (15).

MRI

The classic findings of hemangioma on MRI are that of a homogeneous, well defined lesion with slight lobulations that is low signal relative to liver on the T1 weighted images, becomes progressively brighter (greater than or equal to cerebral spinal fluid) on the T2 weighted images as the time to echo (TE) is lengthened, and demonstrates peripheral puddling of contrast on the enhanced images (of a signal intensity matching the aorta). Approximately 5% of malignant tumors mimic hemangiomas on these long TE images, with the most common mimics being sarcomas, endocrine tumors, and cystadenocarcinomas (16). The common liver metastases (colon, lung, pancreas) are poor mimics on MRI.

One of the useful distinguishing features on MRI is that, whereas both hemangiomas and malignancies tend to have high signal on conventional T2 weighted images, the signal from malignancies tends to decrease as the TE is lengthened, whereas the signal from hemangiomas tends to increase.

MRI was compared to Tc-99m RBC SPECT in 69 lesions seen on CT and/or US ranging in size from 1.0 to 13.0 cm (12). All patients underwent Tc-99m RBC SPECT (single head) and 0.5 Tesla MRI (TR/TE = 2000/50 and 2000/100). The final diagnosis was hemangioma in 64 of these cases. The sensitivity results were as follows:
Size (cm)  SPECT (%) MRI (%) 
1.0 - 1.9 cm 14/24 (58)  20/24 (83) 
2.0 - 2.9 cm 12/13 (92)  11/13 (85) 
3.0-13.0 cm 24-27*/27 (89-100)  27/27 (100)... 
the 3 false negatives on SPECT were ‘hot’ on the
delayed images and the flow images

Summary

Tc-99m RBC SPECT is a highly specific examination in the diagnosis of hemangioma, with only 8 reported false positive cases in the literature. While the sensitivity of MRI is greater than that of SPECT, it lacks SPECT’s high specificity.

References

1. Prakash R, Gupta RK, Narayyanan R, et al. Tc-99m radiocolloid scintigraphy, planar, and SPECT red blood cell imaging and ultrasonography in the diagnosis of hepatic hemangioma. Austr Radiol, 1989;33:237-244.

2. Mungovan JA, Cronan JJ, Vacarro J. Hepatic cavernous hemangiomas: lack of enlargement over time. Radiology,1994;191:115-117.

3. Freeny PC and Marks WM. Hepatic hemangioma: dynamic bolus CT. AJR; 1986:147:711-719.

4. Tamm EP, Rabushka LS, Fishman EK, et al. Intrahepatic extramedullary hematopoiesis mimicking hemangioma on Tc-99m red blood cell SPECT examination. Clin Imag 1995;19:88-91.

5. Ginsberg F, Slavin JD and Spencer RP. Hepatic angiosarcoma: mimicking of angioma on three-phase Tc-99m red blood cell scintigraphy. JNM 1986;27:1861-1863.

6. Swayne LC, Diehl WL, Brown TD and Hunter NJ. False-positive hepatic blood pool scintigraphy in metastatic colon carcinoma. Clin Nucl Med 1991;16:630-632.

7. Farlow DC, Little JM, Gruenewald SM, et al. A case of metastatic malignancy masquerading as a hepatic hemangioma on labelled red blood cell scintigraphy. JNM 1993;34:1172-1174.

8. Rabinowitz SA, McKusik KA, Strauss HW. Tc-99m red blood cell scintigraphy in evaluating focal liver lesions. AJR 1984;143:63-68.

9. Intenzo C, Kim S, Madsen M, et al. Planar and SPECT Tc-99m red blood cell imaging in hepatic cavernous hemangiomas and other hepatic lesions. Clin Nucl Med 1988;13:237-240.

10. Bonanno N, Baldari S, Cerrito A, et al. Diagnosis of hepatic hemangiomas with Tc-99m labelled red blood cell scanning: value of SPECT. J of N Biology and Medicine, 1991;35:135-140.

11. Kudo M, Ikekubo K, Yamamoto K, et al. Distinction between hemangioma of the liver and hepatocellular carcinoma: value of labelled RBC - SPECT scanning. AJR 1989;152:977-983.

12. Birnbaum BA, Weinreb JC, Megibow AJ, et al. Definitive Diagnosis of Hepatic Hemangiomas: MR Imaging versus Tc-99m - labeled red blood cell SPECT. Radiology 1990;176:95-101.

13. Krause T, Hauenstein K, Studier-Fisher B, et al. Improved evaluation of Tc-99m RBC SPECT in hemangioma of the liver. JNM, 1993;34:375-380.

14. Zeissman HA, Silverman PM, Petterson J, et al. Improved detection of small cavernous hemangiomas of the liver with high resolution 3 headed SPECT. JNM 1991;32:2086-2091.

15. Rabinowitz SA, McKusick KA, Strauss HW. Tc-99m red blood cell imaging in evaluating focal liver lesions. AJR 1984;143:63-68.

16. Weissleder R and Stark DD. Magnetic resonance imaging of liver tumors. Seminars in US, CT, and MRI. 1989;10:63-77.

17. Egglin TK, Rummeny E, Stark DD, et al. Hepatic Tumors: Quantitative tissue characterization with MRI. Radiology, 1990:176;107-110.

18. Choi BI, Han MC, Kim CW. Small hepatocellular carcinoma versus small cavernous hemangioma: differentiation with MR imaging at 2.0 T. Radiology 1990;176:103-106.

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J. Anthony Parker, MD PhD, Tony_Parker@bidmc.harvard.edu