False-positive hepatic blood pool SPECT study for hepatic hemangioma

Hepatoblastoma Mimicking Hemangioma in Labeled Red Blood Cell Scintigraphy

Although Tc red blood cell (RBC) scintigraphy is a very specific method to differentiate a hemangioma from other hepatic masses, several cases of false-positive Tc RBC scintigraphy have been previously reported throughout the literature. We report an additional case that presented in a 15-month-old boy with hepatoblastoma showing increased labeled RBC activity mimicking hemangioma.

To what extent can diverse types of liver lesions mimic hemangiomas? A retrospective quantitative analysis of masses found to be positive in SPECT/CT with labeled blood cells - a preliminary report

Background

Although specificity of SPECT/CT examination using technetium-99m radiolabeled red blood cells (Tc-99m-RBC) for detection of liver hemangiomas is very high, it is still not perfect. It is possible to overlook a malignancy. Moreover, the difference in accumulation of RBCs between a hemangioma and uninvolved liver remains unknown.

The aim of the study is to determine the quotients of accumulation of Tc-99m-RBC in hemangiomas and in normal liver parenchyma (HEM/liv), and to verify, whether the quotient could be potentially helpful in distinguishing hemangiomas from other RBC-accumulating liver masses.

Material/Methods

34 liver lesions larger than 1.5 cm classified scintigraphically (qualitatively) in our Department as either typical or suspicious of hemangioma 1.5–4 years earlier were enrolled in this retrospective study. Their SPECT/CT images were acquired 1 hour after in vivo labeling of RBCs with Tc-99m. In reconstructed images, ellipsoidal regions of interest (ROIs) with diameters of about 1.5 cm were created in the assessed lesions (HEM) and in the uninvolved liver parenchyma (liv). The HEM/liv quotients were calculated for each mass. The results were compared with radiological data.

Results

31 lesions were found to be clinically and radiologically typical for hemangiomas, their HEM/liv ratios were at least 1.6 (smaller masses) or 1.8 (larger masses). One lesion with HEM/liv ratio equal to 1.21 was classified as metastasis. Two lesions with HEM/liv 1.42 and 1.46 were classified as benign foci other than hemangioma.

Conclusions

The quantitative analysis can be preliminarily proposed as a helpful tool in the assessment of possible liver hemangiomas.

Multiple hepatic adenomas: Tc-99m RBC liver SPECT findings with pathologic correlation

A 24-year-old man with multiple hepatic masses incidentally detected by ultrasonography underwent Tc-99m RBC liver SPECT. SPECT images showed increased blood pooling mimicking hemangiomas in two of four masses or activity similar to normal liver in the others. The patient had a 3-year history of steroid therapy for rheumatoid arthritis. Computed tomography and magnetic resonance imaging showed multiple liver lesions. Angiography revealed three hypervascular and one hypovascular mass. Microscopic examination of the enucleated specimens disclosed hepatic adenomas with many dilated sinusoids in the masses showing blood pooling and fatty change, and adenomas without dilated sinusoids in the masses not showing blood pooling. This case report shows that the appearance of hepatic adenomas can vary on Tc-99m RBC liver SPECT, depending on whether dilated sinusoid and hepatic adenomas show blood pooling. This is one of the few examples of false-positive findings that can be mistaken for hemangioma.

Pelioid-type hepatocellular carcinoma masquerading as a hepatic hemangioma on technetium-99m red blood cell scintigraphy

Technetium-99m red blood cell (RBC) scintigraphy is a very specific method to differentiate a hemangioma from other hepatic masses. The authors report a case of hepatocellular carcinoma that showed a focal area of increased uptake on Tc-99m RBC SPECT in a 60-year-old man. Dynamic computed tomography and angiography revealed features of both hemangioma and hepatocellular carcinoma. Pathologic examination showed that the portion of the hepatocellular carcinoma that showed increased uptake on Tc-99m RBC scintigraphy had peliosis, which is the likely cause of the radiotracer avidity.

Features of hepatic cavernous hemangioma on planar and SPECT Tc-99m-labeled red blood cell scintigraphy

PURPOSE

To determine the value and diagnostic accuracy of planar and SPECT Tc-99m-labeled red blood cell (Tc-99m RBC) scintigraphy in the investigation of suspected hepatic cavernous hemangioma as found on ultrasound.

PATIENTS AND METHODS

One hundred patients, 89 women (89%) and 11 men (11%), between 22 and 67 years old (mean age, 38 years) were evaluated for liver masses found on abdominal ultrasound. All the patients had previous Tc-99m RBC scintigraphy. The size of the lesions ranged from 1 to 9 cm. The final diagnosis was reached through cytologic biopsy, or histopathologic tests (or all of these).

RESULTS

One hundred thirty lesions were found. With regard to the distribution of the lesions, 116 (89%) were single; 14 (3%) were multiple, with 118 (91%) in the right lobe and 12 (9%) in the left lobe; 83 (64%) were posterior; and 47 (36%) were anterior. With respect to the pattern of radioactivity fill-in, 86 (66%) lesions were typical and 44 (34%) were atypical. The results of Tc-99m RBC scintigraphy showed sensitivity, specificity, and positive and negative predictive and accuracy values of 97%, 83%, 98%, 77%, and 96% respectively. The use of SPECT improved the sensitivity value by 11% for lesions of 1 to 2 cm.

CONCLUSIONS

Tc-99m RBC scintigraphy is the noninvasive technique most helpful in the diagnosis of hepatic hemangioma, especially in those at risk for lesion rupture or bleeding. SPECT should be performed whenever planar imaging fails to show the lesion by 2 hours. The use of ultrasound should precede scintigraphy for two important reasons: the size and the location of the lesion. Location of the lesion (anterior or posterior) is important for optimal gamma camera acquisition parameters. Lesions less than 1 cm are cannot be detected because they are beyond the limit of spatial resolution of the gamma camera we used.

Scintigraphic evaluation of hepatic mass lesions: emphasis on hemangioma detection

Nuclear medicine imaging techniques continue to play a unique role in the evaluation of hepatic masses. Although many useful radiodiagnostic agents are available, the predominant nuclear medicine study used to evaluate hepatic masses in this decade is technetium-labeled red blood cell "blood-pool" scintigraphy. Hepatic blood-pool scintigraphy is extremely useful for the confirmation or exclusion of benign hepatic hemangiomas. This technique was first described in the 1970s and has vastly improved since that time. This improvement has been caused predominantly by advancements in instrumentation, especially the development of single photon emission computed tomography (SPECT) imaging. However, a perfusion/blood-pool mismatch remains unchanged as the hallmark finding for hepatic hemangiomas. The sensitivity and specificity of blood-pool scanning for the detection of hemangiomas has continued to increase over the years, and has not been equaled or surpassed by other radiographic modalities, with the possible exception of magnetic resonance imaging. Furthermore, blood-pool imaging is relatively inexpensive, simple to perform, and highly accurate. When a suspected hepatic hemangioma is confirmed by a positive radionuclide blood-pool study, the clinical evaluation of patients with hepatic masses can generally be terminated.

Nuclear imaging of solid hepatic masses

This review has focused on the unique role of radionuclide scintigraphy in characterization of hepatic mass lesions. Radionuclide scintigraphy, unlike most other imaging modalities, is based on specific physiological and biochemical properties of each pathological entity that affects the liver. Hepatic scintigraphy, with its widespread availability, noninvasive nature, and relatively low cost is a powerful adjunct to other imaging techniques in the investigation of hepatic mass lesions. We have reviewed clinical presentation and characteristic findings of most hepatic lesions and have described reported findings with all available imaging modalities with particular emphasis on hepatic scintigraphy (Table 1) as well as a suggested algorithm for workup of solid hepatic masses (Fig 6). Additionally, the role of newer, more specialized techniques including PET scanning, 123I-labeled VIP, and 111In-labeled DTPA-D-Phe-octreotide scanning are reviewed. Hepatic nuclear scintigraphy continues to play an important role in the management of patients with solid hepatic masses.