Contrast-enhancing ultrasonography in focal splenic lesions: Staging accuracy J.A. Jimenez-Lasanta, E. Barluenga, L. Castro, C. Roque, S. Mourelo, A. Olazabal. HUGTIP-Badalona. SPAIN

Purpose  To investigate the role of contrast-enhanced harmonic ultrasonography (CEUS) with Sono Vue in the differentiation between benign and malignant focal splenic lesions.  To correlate the US findings with other imaging modalities, such as CT, PET and MR.

Material and methods  Prospective selection of 45 patients with focal splenic lesions detected by B-mode US in our tertiary hospital.  Patients were examined following an approved protocol after an intravenous injection of 2,4 ml of Sono Vue.  The spleen was imaged continuously during 3 minutes: All the 3 phases: - arterial 30 sec. - parenchymal 60 sec. - delayed sec. Using low mechanical index US.

Results  21 benign splenic lesions - E chogenic cyst, 7 - Ischemic lesions, 7 - Hemangioma, 2 - Angiomatosis or Klippel-Trenaunay syndrome, 1 - Kassabach-Merrith syndrome, 1 - Hamartoma-splenoma, 2 - Hematoma, 1  24 lesions were characterized as malignant - Non Hogkin lymphoma, 8 - Hodgkin lymphoma, 7 - Metastasis, 6 - Hemangiopericytoma, 1 - Angiosarcoma, 1 - Hemangiendothelioma, 1

Solid homogenous mass, rounded, well- defined, with mixed echotexture and hyperechoic, with cystic changes. With Sonovue, in all phases are increased enhancement, less in delayed phase, compared with the surrounding splenic parenchyma, also with cystic changes. Hamartoma

- Iso-hypoatenuated lesion on CT relative to normal spleen before and after IV contrast, with thin calcification. Also known as splenoma or nodular hyperplasia of the spleen. - They have been associated with other hamartomas elsewhere in the body. - They have been reported in cases of tuberous sclerosis and Wiskott-Aldrich-like syndrome.

. Splenic infarctions B Mode US shows several hypo-anechoic areas in the spleen

. Sono Vue in all phases shows demarcation of the hypo-anechoic areas with wedge-shaped borders

. CT scan shows several low attenuation areas, with capsular retraction and wedge-shaped borders

Angiosarcoma A 61 year-old patient was admitted for toxic syndrome and left upper quadrant pain Angiosarcoma is a very rare vascular neoplasm, that represents the most common non hematolymphoid malignant tumor of the spleen. Longitudinal B-Mode US of the left upper quadrant region shows a well-defined mass (arrowheads) of heterogeneous echotexture

 Associated with previous chemoterapy for lymphoma and radiation therapy for breast cancer.  Appears to arise from splenic sinus endothelial cells.  Cystic areas within the mass are frequently identified and likely reflect areas of necrosis and hemorrhage. Color Doppler US shows increased vascularity throughout the spleen

 On CT, the most common appearance is that of an ill- defined splenic mass with heterogeneous contrast enhancement and areas of necrotic degeneration  There is also evidence of intraperitoneal hemorrhage Contrast–enhanced CT scan shows a rim- enhancing splenic mass with central area of necrosis and associated hemoperitoneum (arrow)

Hemangiopericytoma -It is well known that hemangiopericytoma has relatively higt malignant potential - It is a rare vascular lesion that appears to arise from Zimmerman pericytes - 50% of these tumors arise in the lower extremities and soft tissues, and 25% have abdominal origin

Hypoechoic nodules on B- Mode sonograms, with a strong enhancement is seen in early phase with a wash-out in parenchymal phase Hemangiopericytoma

Hypointense nodules are seen on differences MRI sequences. Lesions were not identified on either CT scans or technetium- 99 sulfure colloid scintigrams.

Splenic metastasis B-Mode US shows an infiltrating large splenic mass with two different components, solid and cystic There are increased Doppler Color US  A patient with a previous endometrial adenocarcinoma presented with a big spleen mass  The mass had cystic areas and parenchymal sparring of neighbours organs such as the gastric posterior wall and diaphragm  There was also pleural effusion

. CEUS shows the arterial enhancement, with persistence in parenchymal phase, and less in late phase.

CT images of the same patient demonstrate the neighbour organs involved by the splenic malignant lesion, that are stomach, diaphragm and retroperitoneum.

. Hodgkin disease B-Mode Us shows an apparently homogenous spleen with pleural effusion CEUS shows a small lesion that washes- out in the parenchymal phase

. CEUS shows a small lesion that washes-out in parenchymal phase. That result was not demonstrated in arterial CEUS phase, even not by CT scan (hypoatenuated nodes in the liver )

Summary  Benign lesions typically showed no contrast enhancement or showed contrast enhancement in the early phase, followed by contrast enhancement in the parenchymal phase (60 seconds)  Malignant lesions typically presented a combination of contrast enhancement in the early phase, followed by rapid wash-out in the parenchymal phase  In our serie, malignant nodules were detected only in 16 patients with CT or FDG PET, whereas a total of 24 were diagnosed by CEUS

Conclusion  CEUS is helpful in the differentiation between benign and malignant lesions of the spleen  CEUS also shows, in our experience, more sensitivity than CT or FDG PET in the detection of malignant splenic involvement

Suggested Reading 1- Abbott RM, Levy AD, Aguilera NS, et al. Primary vascular neoplasms of the spleen: Radiologic-pathologic correlation. Radiographics 2004;24: Von Herbay A, Barreiros AP, Ignee A, et al. Contrast- Enhanced ultrasonography with Sono Vue. Differentiation between benign and malignant lesions of the spleen. J Ultrasound Med 2009;28: Picardi M, Soricelli A, Pane F, et al. Contrast-enhanced harmonic compound US of the spleen to increase staging accuracy in patients with with Hodgkin lymphoma: a prospective study. Radiology 2009; 251(2): Gorg C. The forgotten organ: contrast enhanced sonography of the spleen. Eur J Radiol. 2007;64(2):