DOI:10.2214/AJR.04.1249
AJR 2006; 186:1533-1547
© American Roentgen Ray Society
MRI of Focal Splenic Lesions Without and With Dynamic Gadolinium Enhancement
Antonio Luna1,
Ramón Ribes2,
Pilar Caro3,
Luis Luna1,
Eugenia Aumente4 and
Pablo R. Ros5
1 Department of Radiology, MR Unit, Clinica Las Nieves, Sercosa, Carmelo Torres
2, Jaén 23007, Spain.
2 Department of Radiology, MR Unit, Reina Sofia Hospital, Córdoba 14004,
Spain.
3 MR Unit, Dadisa, Recinto Inferior Zona Franca, Cádiz 11001,
Spain.
4 MR Unit, Ressalta, Hospital San Juan de Dios, Córdoba 14012,
Spain.
5 Department of Radiology, Brigham and Women's Hospital, Harvard Medical School,
Boston, MA 02115.
Received August 6, 2004;
accepted after revision March 15, 2005.
Address correspondence to A. Luna
(aluna70{at}sercosa.com).
Abstract
OBJECTIVE. Our purpose was to identify the MR features of focal
splenic lesions with an emphasis on enhancement patterns. The addition of a
contrast-enhanced dynamic sequence to unenhanced MR images improves the study
of focal splenic lesions. The analysis of the MR features along with the
clinical history permits either the characterization of the most common
splenic lesions or improvement in the detection of malignant diseases.
CONCLUSION. Dynamic contrast-enhanced MRI improves the detection and
characterization of focal splenic lesions.
Keywords: CT • lymphoma • MRI • spleen
Introduction
State-of-the-art MRI sequences, including the use of dynamic
contrast-enhanced series on immediate and delayed acquisitions, permit the
characterization of the most common splenic lesions, such as cysts, small
hemangiomas, and hamartomas; and improvement in the detection of malignant
diseases such as lymphoma and metastases. Nevertheless, percutaneous or
surgical biopsy is necessary when malignancy is suspected or focal lesions
with atypical MRI features are present.
Appendix 1 lists the
classification of focal splenic lesions discussed in this article.
Technique
Although unenhanced MRI detects most cysts and hemangiomas, it is usually
not sensitive enough for the detection of less common splenic lesions. The use
of a dynamic contrast-enhanced gradient-echo sequence improves the detection
of focal splenic lesions, mainly in the acquisition obtained immediately after
contrast administration, allowing a better differentiation between normal and
abnormal spleen [1] because of
differences in blood supply. Our standard protocol includes a turbo
gradient-echo axial T1-weighted sequence; an axial and coronal breath-hold
turbo spin-echo T2-weighted sequence; an axial STIR sequence; and a 3D
fat-suppressed gadolinium-enhanced dynamic series with immediate (12 sec after
contrast injection) and 1- and 5-min delayed contrast-enhanced
acquisitions.
Normal Variants
Notches, clefts, and accessory spleens (spleniculi) can be misinterpreted
as splenic nodules. The identical signal intensity of these pseudolesions to
splenic parenchyma in all sequences allow their characterization. MRI
appearance of these nodules is similar to that of splenosis.
Polysplenia Syndrome
Polysplenia syndrome is a congenital disorder associating thoracoabdominal
abnormalities and complete situs ambiguous (Figs.
1A and
1B), which typically shows
multiple splenic nodules.
View larger version (123K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —3-month-old girl with polysplenia syndrome. After chest radiography
showed dextrocardia, MRI was performed to rule out associated malformations.
Axial unenhanced (A) and delayed contrast-enhanced (B) turbo
gradient-echo T1-weighted sequences show mirror-image location of upper
abdominal viscera and vessels. Right hypochondrium is occupied by multiple
independent splenic nodules of different sizes that show homogeneous
enhancement in delayed phase. Findings correspond to polysplenia syndrome
associated with situs ambiguous.
|
|
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1B —3-month-old girl with polysplenia syndrome. After chest radiography
showed dextrocardia, MRI was performed to rule out associated malformations.
Axial unenhanced (A) and delayed contrast-enhanced (B) turbo
gradient-echo T1-weighted sequences show mirror-image location of upper
abdominal viscera and vessels. Right hypochondrium is occupied by multiple
independent splenic nodules of different sizes that show homogeneous
enhancement in delayed phase. Findings correspond to polysplenia syndrome
associated with situs ambiguous.
|
|
Infectious Lesions
MRI surpasses enhanced CT in the evaluation of fungal infections
[2]. Candida albicans,
Aspergillus fumigatus, and Cryptococcus neoformans are
responsible for the majority of these infections in immunocompromised
patients. Acute Candida abscesses appear on fat-suppressed turbo
spinecho T2-weighted images (Figs.
2A and
2B) as small hyperintense
subcapsular lesions that do not usually show peripheral enhancement in the
acute stage because of the immunocompromised state of these patients; or in
the chronic stage because of fibrotic changes
[3]. Bacterial abscesses, which
are usually larger than fungal ones, are frequently associated with
endocarditis and typically show peripheral and perilesional enhancement on
contrast-enhanced sequences [4]
(Figs. 1A and
1B). Hydatid cysts are
secondary to infection by Echinococcus granulosus that appear as
single or multiple cysts with or without wall calcifications (Figs.
4A,
4B and
4C). Healed granulomas are
better depicted by CT than MRI because they are completely calcified.
View larger version (136K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2A —34-year-old man with HIV infection and acute hepatosplenic
candidiasis. Axial fat-saturated turbo spin-echo T2-weighted image shows
multiple round hyperintense lesions in liver and spleen (arrowheads)
representing Candida albicans microabscesses.
|
|
View larger version (122K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2B —34-year-old man with HIV infection and acute hepatosplenic
candidiasis. Axial contrast-enhanced turbo spin-echo T1-weighted delayed phase
image shows homogeneous enhancement of hepatic lesions and scarce enhancement
of splenic lesions (arrowheads), with only one of them detectable.
Fat-saturated turbo spin-echo T2-weighted images make lesions appear more
conspicuous.
|
|
View larger version (95K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4A —46-year-old woman with splenic hydatid cyst. Septated hyperintense
splenic mass is seen on coronal turbo spin-echo T2-weighted image. Smaller
peripheral cyst represents daughter cyst (arrow).
|
|
View larger version (184K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4B —46-year-old woman with splenic hydatid cyst. Axial gradient-echo
unenhanced (B) and delayed contrast-enhanced (C) 3D T1-weighted
images show cystic nature of mass. These are typical features of hydatid
cysts, although similar appearances can be found in epithelial cysts or
lymphangiomas. Diagnosis of hydatid cyst was established after
splenectomy.
|
|
View larger version (191K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4C —46-year-old woman with splenic hydatid cyst. Axial gradient-echo
unenhanced (B) and delayed contrast-enhanced (C) 3D T1-weighted
images show cystic nature of mass. These are typical features of hydatid
cysts, although similar appearances can be found in epithelial cysts or
lymphangiomas. Diagnosis of hydatid cyst was established after
splenectomy.
|
|
Cysts
Cysts are the most common benign focal splenic masses
[2]. They can be divided into
epithelial or true cysts, which are lined with epithelium and may show
septations and peripheral calcifications (Figs.
5A and
5B); and false cysts or
pseudocysts that can be posttraumatic or secondary to pancreatitis and usually
have a more heterogeneous appearance than true cysts (Figs.
6A and
6B).
View larger version (140K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5A —44-year-old woman with splenic epithelial cyst. Huge cystic mass was
discovered in left upper quadrant on sonography. MRI was performed to
determine its organ of origin. Axial unenhanced (A) and delayed
contrast-enhanced (B) turbo gradient-echo T1-weighted images show huge
homogeneous nonenhancing mass intimately related to spleen, which is shifted
laterally. Mass corresponds to splenic epithelial cyst as confirmed after
splenectomy.
|
|
View larger version (141K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 5B —44-year-old woman with splenic epithelial cyst. Huge cystic mass was
discovered in left upper quadrant on sonography. MRI was performed to
determine its organ of origin. Axial unenhanced (A) and delayed
contrast-enhanced (B) turbo gradient-echo T1-weighted images show huge
homogeneous nonenhancing mass intimately related to spleen, which is shifted
laterally. Mass corresponds to splenic epithelial cyst as confirmed after
splenectomy.
|
|
View larger version (127K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6A —57-year-old man with pancreatic pseudocyst with splenic involvement.
Patient had history of acute pancreatitis episodes. Huge complicated cyst was
discovered during routine sonography study in upper abdomen. MRI was performed
for further characterization of lesion. Sagittal unenhanced (A) and
delayed contrast-enhanced (B) turbo field-echo T1-weighted images
reveal bilobulated cystic mass surrounding and extending to spleen
(asterisk). Note presence of fluid-fluid level (arrows)
within superior component of mass with hyperintense signal on T1-weighted
sequence of dependent component, indicating hemorrhagic content.
|
|
View larger version (137K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 6B —57-year-old man with pancreatic pseudocyst with splenic involvement.
Patient had history of acute pancreatitis episodes. Huge complicated cyst was
discovered during routine sonography study in upper abdomen. MRI was performed
for further characterization of lesion. Sagittal unenhanced (A) and
delayed contrast-enhanced (B) turbo field-echo T1-weighted images
reveal bilobulated cystic mass surrounding and extending to spleen
(asterisk). Note presence of fluid-fluid level (arrows)
within superior component of mass with hyperintense signal on T1-weighted
sequence of dependent component, indicating hemorrhagic content.
|
|
Vascular Lesions
Focal Vascular Lesions
Benign tumors—Hemangioma is the second most common focal
lesion and the most common benign tumor of the spleen
[5]. Most hemangiomas are
smaller than 2 cm [4],
well-defined, homogeneous, hypoto isointense on T1-weighted images, and most
commonly hyperintense on T2-weighted images compared with splenic parenchyma
(Figs. 6A and
6B). On dynamic
contrast-enhanced studies, they usually show peripheral enhancement with
centripetal, delayed progression
[5] (Figs.
7A,
7B,
7C and
7D), although the typical
nodular, peripheral enhancement of hepatic hemangiomas is uncommon
[2,
5]. Smaller hemangiomas may
also show homogeneous enhancement on immediate postcontrast acquisitions
(Figs. 8A and
8B), remaining enhanced on
delayed images [2]. Therefore,
any small splenic lesion that is hyperintense on T2-weighted images and shows
homogeneous or peripheral enhancement on immediate postcontrast images should
be considered a hemangioma. Larger hemangiomas are heterogeneous with areas of
hemorrhage and thrombosis and enhance in a centripetal fashion with persistent
nonenhancing areas [5] (Figs.
9A and
9B). Therefore, larger
hemangiomas need follow-up or biopsy to rule out angiosarcoma. Littoral cell
angioma and hemangioendothelioma are rare, benign, vascular tumors that can
show siderotic nodules [5].
View larger version (143K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7A —8-year-old boy with multiple small cavernous hemangiomas showing
centripetal enhancement pattern. Coronal fat-saturated turbo spin-echo
T2-weighted image shows multiple hyperintense splenic nodules.
|
|
View larger version (167K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7B —8-year-old boy with multiple small cavernous hemangiomas showing
centripetal enhancement pattern. Immediate (B), 1 min (C), and
delayed (D) postcontrast gradient-echo T1-weighted images show
progressive centripetal enhancement typical of hemangiomas. Note progressive
peripheral enhancement on immediate- and 1-min postcontrast images and how
nodules become almost completely isointense to splenic parenchyma on delayed
acquisition.
|
|
View larger version (173K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7C —8-year-old boy with multiple small cavernous hemangiomas showing
centripetal enhancement pattern. Immediate (B), 1 min (C), and
delayed (D) postcontrast gradient-echo T1-weighted images show
progressive centripetal enhancement typical of hemangiomas. Note progressive
peripheral enhancement on immediate- and 1-min postcontrast images and how
nodules become almost completely isointense to splenic parenchyma on delayed
acquisition.
|
|
View larger version (175K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 7D —8-year-old boy with multiple small cavernous hemangiomas showing
centripetal enhancement pattern. Immediate (B), 1 min (C), and
delayed (D) postcontrast gradient-echo T1-weighted images show
progressive centripetal enhancement typical of hemangiomas. Note progressive
peripheral enhancement on immediate- and 1-min postcontrast images and how
nodules become almost completely isointense to splenic parenchyma on delayed
acquisition.
|
|
View larger version (136K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8A —43-year-old man with splenic capillary hemangioma showing
homogeneous enhancement pattern. Axial unenhanced (A) and immediate
postcontrast (B) volumetric 3D gradient-echo T1-weighted images reveal
homogeneous enhancement typical of splenic capillary hemangiomas. On delayed
acquisition (not shown), although lesion showed some washout, it remained more
enhanced than splenic parenchyma.
|
|
View larger version (148K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 8B —43-year-old man with splenic capillary hemangioma showing
homogeneous enhancement pattern. Axial unenhanced (A) and immediate
postcontrast (B) volumetric 3D gradient-echo T1-weighted images reveal
homogeneous enhancement typical of splenic capillary hemangiomas. On delayed
acquisition (not shown), although lesion showed some washout, it remained more
enhanced than splenic parenchyma.
|
|
View larger version (69K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9A —8-year-old boy with systemic angiomatosis and cavernous hemangioma
with central scar. Unenhanced (A) and delayed contrast-enhanced
(B) fat-saturated turbo spin-echo T1-weighted images show hypointense
nodule that shows peripheral and heterogeneous internal enhancement after IV
contrast administration, related to presence of central scar, in cavernous
hemangioma. Biopsy was not necessary as this patient had multiple hemangiomas
in spleen, liver, and neck (not shown).
|
|
View larger version (89K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 9B —8-year-old boy with systemic angiomatosis and cavernous hemangioma
with central scar. Unenhanced (A) and delayed contrast-enhanced
(B) fat-saturated turbo spin-echo T1-weighted images show hypointense
nodule that shows peripheral and heterogeneous internal enhancement after IV
contrast administration, related to presence of central scar, in cavernous
hemangioma. Biopsy was not necessary as this patient had multiple hemangiomas
in spleen, liver, and neck (not shown).
|
|
View larger version (148K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3A —53-year-old man with Staphylococcus aureus abscess
secondary to endocarditis. and B, Axial gradient-echo unenhanced
(A) and immediate postcontrast (B) 2D fat-suppressed T1-weighted
images show peripheral enhancement of huge cystic-appearing lesion. Clinical
data and peripheral enhancement on enhanced MRI sequences led to diagnosis of
splenic abscess.
|
|
View larger version (144K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3B —53-year-old man with Staphylococcus aureus abscess
secondary to endocarditis.B, Axial gradient-echo unenhanced (A)
and immediate postcontrast (B) 2D fat-suppressed T1-weighted images
show peripheral enhancement of huge cystic-appearing lesion. Clinical data and
peripheral enhancement on enhanced MRI sequences led to diagnosis of splenic
abscess.
|
|
Malignant neoplasms—Angiosarcoma typically appears as
multiple nodular heterogeneous masses, including siderotic nodules, with
intense and heterogeneous enhancement
[5]. In the uncommon case of
whole spleen replacement, an increased risk for splenic rupture exists.
Hemangiopericytoma rarely involves the spleen.
Nonneoplastic lesions—On MRI, splenic infarcts are more
conspicuous on delayed contrast-enhanced images as defined perfusion defects
[2]. A typical feature is the
rim sign or capsular enhancement caused by blood supply from capsular vessels
[6]. Intrasplenic hematomas in
the acute phase show high signal intensity on T1-weighted images
[6]. Later, they usually
present as a cystic mass. Old, healed hematomas are commonly hypointense on
T1- and T2-weighted images (Figs.
10A,
10B and
10C).
View larger version (124K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10B —52-year-old man with splenic hematoma. Axial unenhanced (B)
and delayed contrast-enhanced (C) gradient-echo T1-weighted images show
hypointense mass on T1-weighted image with peripheral and heterogeneous
internal enhancement. Appearance of lesion on MRI was diagnostic and did not
change in several follow-up MRI studies.
|
|
View larger version (137K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 10C —52-year-old man with splenic hematoma. Axial unenhanced (B)
and delayed contrast-enhanced (C) gradient-echo T1-weighted images show
hypointense mass on T1-weighted image with peripheral and heterogeneous
internal enhancement. Appearance of lesion on MRI was diagnostic and did not
change in several follow-up MRI studies.
|
|
Diffuse Vascular Lesions
Hemangiomatosis is a rare vascular tumorlike entity that has a similar
appearance to angiosarcoma (Figs.
11A,
11B and
11C). On MRI, lymphangioma
usually presents as a multicystic lesion, although some of the cysts may be
hyperintense on T1-weighted images (Figs.
12A and
12B) because of their
proteinaceous or hemorrhagic content
[5]. Although malignant
degeneration of lymphangioma is rare, MRI is able to show intracystic solid
components [5]. Peliosis
usually presents in immunocompromised patients
[5], and its most common MRI
appearance is that of multiple cystic and hemorrhagic nodules, sometimes of
hypervascular nature, associated with siderotic nodules (Figs.
13A and
13B).
View larger version (172K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11A —41-year-old woman with diffuse splenic hemangiomatosis. Coronal
turbo spin-echo T2-weighted image shows multiple hyperintense focal splenic
lesions (arrowheads) and hypointense nodule representing siderotic
nodule (arrow) in enlarged spleen.
|
|
View larger version (133K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11B —41-year-old woman with diffuse splenic hemangiomatosis. Axial
unenhanced gradient-echo T1-weighted image shows hypovascular nodules with
areas of magnetic susceptibility artifact (arrows) representing
siderotic nodules.
|
|
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 11C —41-year-old woman with diffuse splenic hemangiomatosis. Postcontrast
(1 min) gradient-echo T1-weighted image reveals subtle peripheral enhancement
of both nodules (arrows). Superior nodule also presents heterogeneous
internal enhancement. Heterogeneous splenic appearance is also possible in
cases of angiosarcoma or littoral cell angioma.
|
|
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12A —27-year-old woman with splenic lymphangioma. Complex cystic mass was
detected in previous routine sonography study and confirmed later on enhanced
CT. Axial unenhanced (A) and contrast-enhanced (B) gradient-echo
T1-weighted images show subcapsular multilocular mass with hypo-
(arrowheads) and hyperintense (arrow) nonenhancing areas,
revealing their cystic nature. Hyperintense areas were secondary to
proteinaceous content. Diagnosis was confirmed after splenectomy. Ghosting
artifact was result of poor breath-holding.
|
|
View larger version (121K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 12B —27-year-old woman with splenic lymphangioma. Complex cystic mass was
detected in previous routine sonography study and confirmed later on enhanced
CT. Axial unenhanced (A) and contrast-enhanced (B) gradient-echo
T1-weighted images show subcapsular multilocular mass with hypo-
(arrowheads) and hyperintense (arrow) nonenhancing areas,
revealing their cystic nature. Hyperintense areas were secondary to
proteinaceous content. Diagnosis was confirmed after splenectomy. Ghosting
artifact was result of poor breath-holding.
|
|
View larger version (127K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13A —72-year-old woman with disseminated tuberculosis and hepatosplenic
peliosis. Axial T1 gradient-echo unenhanced (A) and immediate
postcontrast (B) images show multicystic mass on spleen
(arrows, B) with septal and peripheral enhancement and several
liver lesions with peripheral enhancement or multicystic appearance
(arrowheads, B). Liver lesions were not detectable on
unenhanced image.
|
|
View larger version (138K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 13B —72-year-old woman with disseminated tuberculosis and hepatosplenic
peliosis. Axial T1 gradient-echo unenhanced (A) and immediate
postcontrast (B) images show multicystic mass on spleen
(arrows, B) with septal and peripheral enhancement and several
liver lesions with peripheral enhancement or multicystic appearance
(arrowheads, B). Liver lesions were not detectable on
unenhanced image.
|
|
Nonvascular Tumors
Benign
Hamartoma is a rare nonneoplastic tumor that usually appears as a sharply
defined, rounded, single solid lesion
[2]. Its heterogeneous
hyperintensity on T2-weighted images (Fig.
14A,
14B and
14C) and its typical faint
heterogeneous enhancement on immediate postcontrast-enhanced images are key
features in the differentiation between hamartomas and hemangiomas
[7]. On delayed postcontrast
images, hamartoma enhances in a relatively uniform and intense fashion
(Fig. 14C) with central
hypovascular areas [7].
Therefore, MRI is the preferable imaging technique for its distinction from
hemangiomas.
View larger version (101K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14B —3-year-old boy with splenic hamartoma. Unenhanced (B) and
delayed contrast-enhanced (C) turbo spin-echo T1-weighted images show
intense mildly heterogeneous enhancement within mass, which was hypointense on
precontrast image. This is typical presentation of hamartoma. Larger
hemangiomas may have similar appearance, and biopsy may be necessary for
differentiation. Although splenectomy was performed in this case, follow-up
imaging may be acceptable strategy to assess benign origin of hamartomas.
|
|
View larger version (109K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 14C —3-year-old boy with splenic hamartoma. Unenhanced (B) and
delayed contrast-enhanced (C) turbo spin-echo T1-weighted images show
intense mildly heterogeneous enhancement within mass, which was hypointense on
precontrast image. This is typical presentation of hamartoma. Larger
hemangiomas may have similar appearance, and biopsy may be necessary for
differentiation. Although splenectomy was performed in this case, follow-up
imaging may be acceptable strategy to assess benign origin of hamartomas.
|
|
Malignant
Lymphoma is the most common splenic malignancy
[4] and can present as multiple
focal lesions or diffuse involvement or, more rarely, as a single mass (Figs.
15A,
15B and
15C). Both Hodgkin's and
non-Hodgkin's lymphoma may present in the spleen as the primary site or as a
part of systemic involvement. Immediate postcontrast MRI images surpass CT in
their evaluation [2], although
the role of MDCT is not established yet. Lymphomaous nodules tend to be
isointense to splenic parenchyma on T1- and T2-weighted images
(Fig. 12B), although they can
be hypointense on T2-weighted images
[2,
6]. This feature is useful in
their distinction from metastases, which are rarely hypointense on T2-weighted
images [2]. Immediate
postcontrast images show hypovascular nodules, which usually become isointense
to the spleen within the first minute after contrast administration
[4] (Figs.
16A,
16B,
16C and
16D).
View larger version (143K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15A —47-year-old woman with left flank pain and primary splenic nodular
non-Hodgkin's lymphoma. Splenic mass was detected in previous sonography
study, and MRI study was performed for its characterization. Axial STIR image
reveals irregular heterogeneous hypointense mass with extension beyond splenic
margins (white arrows).
|
|
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15B —47-year-old woman with left flank pain and primary splenic nodular
non-Hodgkin's lymphoma. Splenic mass was detected in previous sonography
study, and MRI study was performed for its characterization. Axial unenhanced
(B) and immediate postcontrast (C) gradient-echo T1-weighted
images show hypovascular mass on immediate image that becomes isointense to
spleen on delayed acquisition (not shown). Notice presence of small peripheral
siderotic nodules (arrowhead).
|
|
View larger version (153K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 15C —47-year-old woman with left flank pain and primary splenic nodular
non-Hodgkin's lymphoma. Splenic mass was detected in previous sonography
study, and MRI study was performed for its characterization. Axial unenhanced
(B) and immediate postcontrast (C) gradient-echo T1-weighted
images show hypovascular mass on immediate image that becomes isointense to
spleen on delayed acquisition (not shown). Notice presence of small peripheral
siderotic nodules (arrowhead).
|
|
View larger version (164K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16B —56-year-old man with weight loss, weakness, and multinodular
non-Hodgkin's lymphoma. Axial unenhanced (B), immediate postcontrast
(C), and delayed postcontrast (D) gradient-echo T1-weighted
images show multiple small hypovascular nodules on immediate acquisition that
are not detectable on delayed acquisition. Splenectomy was performed and
multinodular non-Hodgkin's lymphoma was confirmed.
|
|
View larger version (166K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16C —56-year-old man with weight loss, weakness, and multinodular
non-Hodgkin's lymphoma. Axial unenhanced (B), immediate postcontrast
(C), and delayed postcontrast (D) gradient-echo T1-weighted
images show multiple small hypovascular nodules on immediate acquisition that
are not detectable on delayed acquisition. Splenectomy was performed and
multinodular non-Hodgkin's lymphoma was confirmed.
|
|
View larger version (178K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 16D —56-year-old man with weight loss, weakness, and multinodular
non-Hodgkin's lymphoma. Axial unenhanced (B), immediate postcontrast
(C), and delayed postcontrast (D) gradient-echo T1-weighted
images show multiple small hypovascular nodules on immediate acquisition that
are not detectable on delayed acquisition. Splenectomy was performed and
multinodular non-Hodgkin's lymphoma was confirmed.
|
|
Chloromas, most commonly associated with chronic lymphocytic leukemia, are
rare. They appear as multiple ill-defined masses without enhancement on
immediate postcontrast images
[2] (Figs.
17A and
17B).
View larger version (93K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 17A —5-year-old boy with acute myeloid leukemia. MRI was performed for
staging after positive bone marrow biopsy. Unenhanced (A) and immediate
postcontrast (B) 3D fat-suppressed gradient-echo T1-weighted images
show multiple hypovascular nodules (arrows, B) not seen on
unenhanced MRI. Nodules became isointense to spleen on delayed acquisition
(not shown). Nodules represent chloromas, which tend to be more conspicuous,
as in cases of lymphoma, on immediate postcontrast acquisition. In this case,
lesions disappeared after chemotherapy.
|
|
View larger version (104K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 17B —5-year-old boy with acute myeloid leukemia. MRI was performed for
staging after positive bone marrow biopsy. Unenhanced (A) and immediate
postcontrast (B) 3D fat-suppressed gradient-echo T1-weighted images
show multiple hypovascular nodules (arrows, B) not seen on
unenhanced MRI. Nodules became isointense to spleen on delayed acquisition
(not shown). Nodules represent chloromas, which tend to be more conspicuous,
as in cases of lymphoma, on immediate postcontrast acquisition. In this case,
lesions disappeared after chemotherapy.
|
|
Metastases are commonly isointense to the spleen on unenhanced sequences
[6], although they can be
hyperintense on T2-weighted images, mainly when necrosis or cystic changes are
present (Fig. 18A).
Hemorrhagic or melanoma metastases can show high signal on T1-weighted images
[2]. These last two features
can be used to distinguish metastases from lymphoma, as lymphoma rarely shows
necrosis or hemorrhage. Metastases are typically hypovascular on immediate
postcontrast images, becoming isointense after the first postcontrast minute
[2] (Figs.
18B,
18c and
18D).
View larger version (143K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 18B —63-year-old woman with treated colon adenocarcinoma and splenic
metastasis. Axial unenhanced (B), immediate postcontrast (C),
and 5-min-delayed postcontrast (D) gradient-echo T1-weighted images
reveal hypovascular mass on immediate acquisition difficult to detect on
delayed acquisition, where remaining central hypovascular area can be seen.
Note correlation between nonenhancing areas on delayed postcontrast
acquisition and hyperintense areas on T2-weighted images, representing areas
of necrosis.
|
|
View larger version (151K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 18C —63-year-old woman with treated colon adenocarcinoma and splenic
metastasis. Axial unenhanced (B), immediate postcontrast (C),
and 5-min-delayed postcontrast (D) gradient-echo T1-weighted images
reveal hypovascular mass on immediate acquisition difficult to detect on
delayed acquisition, where remaining central hypovascular area can be seen.
Note correlation between nonenhancing areas on delayed postcontrast
acquisition and hyperintense areas on T2-weighted images, representing areas
of necrosis.
|
|
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 18D —63-year-old woman with treated colon adenocarcinoma and splenic
metastasis. Axial unenhanced (B), immediate postcontrast (C),
and 5-min-delayed postcontrast (D) gradient-echo T1-weighted images
reveal hypovascular mass on immediate acquisition difficult to detect on
delayed acquisition, where remaining central hypovascular area can be seen.
Note correlation between nonenhancing areas on delayed postcontrast
acquisition and hyperintense areas on T2-weighted images, representing areas
of necrosis.
|
|
Miscellaneous
In cases of lysosomal storage disorders, such as Gaucher's and Niemann-Pick
diseases, MRI may detect splenic nodules and infarcts
[8]
(Fig. 19A). Splenic
sarcoidosis appears as multiple tiny, hypovascular and hypointense nodules on
all sequences [2]. Gamna-Gandy
nodules or siderotic nodules are foci of iron deposits that result from
splenic microhemorrhages. These nodules are usually smaller than 1 cm and
hypointense on all sequences (Fig.
19B). T2*-weighted and gadolinium-enhanced T1-weighted
images increase their conspicuity, rendering MRI superior to sonography and CT
in their detection [6].
View larger version (101K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 19A —Other splenic lesions. 22-year-old woman with nodular splenomegaly
in patient with Niemann-Pick disease type B. Axial fat-saturated T2-weighted
image shows well-defined hypointense splenic nodule (arrow).
Hyperintense splenic nodules on T2-weighted images were also seen in same
patient (not shown). Diagnosis was established according to imaging and
clinical criteria, results of hepatic and bone marrow biopsies, and levels of
glucocerebrosidase and sphingomyelinase.
|
|
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 19B —Other splenic lesions. 56-year-old man with alcoholic cirrhosis and
Gamna-Gandy nodules. Axial contrast-enhanced fat-saturated turbo spin-echo
T1-weighted image shows cirrhotic liver and multiple millimetric hypointense
nodules with associated susceptibility artifact within enlarged spleen.
Siderotic nodules represent areas of microhemorrhages.
|
|
Conclusion
Dynamic enhanced sequences improve the evaluation of focal splenic lesions,
allowing the characterization of cysts, smaller hemangiomas, hamartomas, and
acute fungal infections and increasing the detection rate of metastases and
lymphoma. Biopsy remains necessary for the characterization of larger
hemangiomas and other uncommon vascular lesions and when malignancy is
suspected.
APPENDIX 1: Classification of Focal Splenic Lesions
| 1. Normal variants |
Accessory spleen (spleniculi) |
|
Splenic notches (fetal lobulations) |
| 2. Polysplenia syndrome |
|
| 3. Infectious lesions |
Fungal abscesses |
|
Bacterial abscesses |
|
Echinococcosis |
|
Healed granulomas |
| 4. Cysts |
Epithelial (true cysts) |
|
Pseudocysts (false cysts) |
| 5. Vascular lesions |
|
| A Focal |
|
| 1. Benign tumors |
Hemangioma |
|
Littoral cell angioma |
|
Hemangioendothelioma |
| 2. Malignant neoplasms |
Angiosarcoma |
|
Hemangiopericytoma |
| 3. Nonneoplastic lesions |
Infarct |
|
Hematoma |
| B. Diffuse |
Hemangiomatosis |
|
Lymphangiomas, lymphangiomatosis |
|
Peliosis |
| 6. Nonvascular tumors |
|
| A. Benign |
Hamartomas |
|
Fatty tumors |
| B. Malignant |
Lymphomas |
|
Leukemia |
|
Metastases |
| 7. Miscellaneous |
Storage diseases |
|
Amyloidosis |
|
Sarcoidosis |
|
Gamna-Gandy bodies |
|
Inflammatory pseudotumor |
|
Extramedullary hematopoiesis
|
|
References
- Runge VM, Williams NM. Dynamic contrast-enhanced magnetic resonance
imaging in a model of splenic metastasis. Invest
Radiol 1998; 33:45
-50[Medline]
- Nagasse LL, Richard C, Semelka RC, et al. Spleen. In: Semelka RC.
Abdomino-pelvic MRI. New York, NY: Wisley-Liss,2002
: 491-526
- Semelka RC, Kelekis NL, Sallah S, Worawattanakul S, Ascher SM.
Hepatosplenic fungal disease: diagnostic accuracy and spectrum of appearances
on MR imaging. AJR 1997;169
: 1311-1316 4.[Abstract/Free Full Text]
- Robertson F, Leander P, Ekberg O. Radiology of the spleen.
Eur Radiol 2001;11
: 80-95[CrossRef][Medline]
- Abbott RM, Levy AD, Aguilera NS, et al. From the archives of the
AFIP: primary vascular neoplasms of the spleen: radiologic-pathologic
correlation. RadioGraphics 2004;24
: 1137-1163[Abstract/Free Full Text]
- Ito K, Mitchell DG, Honjo K, et al. MR Imaging of acquired
abnormalities of the spleen. AJR 1997;168
: 697-702[Free Full Text]
- Ramani M, Reinhold C, Semelka RC. Splenic hemangiomas and
hamartomas: MR imaging characteristics of 28 lesions.
Radiology 1997;202
: 166-172[Abstract/Free Full Text]
- Hill SC, Damaska BM, Ling A, et al. Gaucher disease: abdominal MR
imaging findings in 46 patients. Radiology1992; 184:561
-566[Abstract/Free Full Text]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
A. Stang, H. Keles, S. Hentschke, C. U. von Seydewitz, J. Dahlke, E. Malzfeldt, and D. Braumann
Differentiation of Benign From Malignant Focal Splenic Lesions Using Sulfur Hexafluoride-Filled Microbubble Contrast-Enhanced Pulse-Inversion Sonography
Am. J. Roentgenol.,
September 1, 2009;
193(3):
709 - 721.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
