Introduction
The spleen is considered the ” forgotten organ” because of the nonspecific pathologies involving it1.
Often ignored by the clinician and by the radiologist,
splenic lesions can be the key finding in some of the patients.
Also,
given that overlapping features of splenic lesions on imaging studies is often,
it is sometimes hard to determine the causative etiology of a given splenic pathology using imaging studies alone1,
4,
5.
Epidemiology
Most splenic lesions are detected incidentally,
posing a challenge for both interpreting and referring physicians in determining the need for and type of further evaluation.
About 1% of patients in an emergency room population undergoing computed tomography (CT) scans for abdominal pain or trauma had incidental splenic lesions.1
However,
in patients with a known malignancy or symptoms attributable to possible splenic pathology,
the incidentally discovered splenic lesion may be more significant.
Clinical factors must be taken into account when evaluating a splenic lesion,
in order to narrow the differential diagnosis:
- pain attributable to the spleen;
- signs and symptoms of infection;
- immune status;
- history of known malignancy;
- associated findings on imaging of the chest,
abdomen or pelvis;
- history of abdominal trauma 1,
4,
5.
- laboratory values,
such as white blood cell count;
Among all cancers,
blood cancers have had a percentage of 11% in Canada,
in 201613.
By types and subtypes,
statistics may differ related to the geographic region (table 1). 13,
14
Table 1 - Epidemiological data for oncohematological patients 13,
14
Pathology
|
Subtype |
Percentage of all blood cancers |
Percentage of the type |
Median age at diagnose |
Lymphoma
|
Non-Hodkin |
31,37%
|
85.6%
|
69.1 |
Hodkin
|
14.4% |
41.3 |
Leukemia
|
Acute lymphoblastic leukemia |
16,29%
|
5% |
15 |
Chronic lymphocytic leukemia |
24% |
67 |
Acute myeloid leukemia |
44% |
71 |
Chronic myeloid leukemia |
12% |
64 |
Other |
15% |
- |
Myeloma |
|
5,39% |
|
69 |
Myelodysplastic syndrome
|
|
17,23% |
|
>65 |
Myeloproliferative disorders |
Essential Thrombocythemia |
6,29% |
|
60-65 |
Polycythemia Vera |
10,35% |
|
>50
|
Myelofibrosis |
1,3% |
|
69
|
Table 1 - Epidemiological data 13,
14
The oncohematologic patient may experience complications of the underlying disease such as hemorrhagic or ischemic complications (attributed to both hemostasis and treatment) as well as infectious (attributed to immunosuppression and cytostatic disorders).
There is very few data in the documented sources about these complications,
statics being various.
Techniques: 2,
3
Regarding CT examination,
guidelines suggest a three-phase protocol:
- native phase (useful only for detection of fresh hemorrhage);
- two post i.v. contrast injection phases (300-370 mg I/ml; 1-1,5 ml/kg depending on the patient’s weight) using a power injector at a rate of 3.5-4 ml/sec;
- arterial phase starts at 30 seconds after the onset of the injection,
with cranio-caudal movement from the diaphragm to the iliac bones (or whole pelvis in case of splenomegaly);
- late enhancement phase,
splenic parenchymal phase begins 60 to 90 seconds after the start of the injection;
After the examination,
images can be processed,
by multiplanar reconstruction (MPR),
maximum intensity projection reconstruction (MIP),
or volumetric rendering technique (VRT).
MRI examination protocol:
For MRI examination,
performed on a 1.5T scanner,
it is necessary to use a torso phased array coil and administration of i.v.
gadolinium-based contrast agent (0.1 ml/kg).
The protocol must include:
-
breath-hold sequences,
T2 fast-spin echo with fat saturation (T2TSEfs),
in/out-of-phase,
T1 Fat Sat weighted images,
axial and coronal single shot T2 FSE with long and short TE,
diffusion sequence and ADC map;
-
three phase 3D-T1 GRE weighted with fat saturation after dynamic i.v.
Gd-BOPTA injection: arterial phase (30 sec),
portal phase (70 sec) and equilibrium/late phase (120 sec);