Learning objectives
To learn the causes and imaging presentations of bone marrow edema (BME) in the knee,
revisiting several MRI cases.
Several cases from the authors practices will be presented,
grouped according to the edema mechanisms as adapted from the original classification by Eustace.[1]
Background
Bone marrow edema represents an increase in interstitial fluid,
as such it has the MR characteristics of increased water content,
namely a low/intermediate signal on T1-weighted images and a high signal on T2 and PD-weighted images.[2]Water sensitive sequencessuch as short-tau inversion recovery (STIR) imagingarevery sensitive in detecting bone marrow edema as it appears hyperintense compared with normal bone marrow.[3]
Following intravenous gadolinium administration minimal delayed enhancement can be seen with marrow edema,
particularly in the vasogenic forms (as explained ahead).[2]
In contrast to stroke,
posttraumatic...
Findings and procedure details
Below we present a listing of several entities associated with bone marrow edema of the knee,
arranged according to the pathophysiology of the edema for each case (slightly adapted from the first classification described by Eustace[1]).
Several examples collected from our practice are used to illustrate and further discuss these entities:
1.
Traumatic/Degenerative
a.
Osteoarthritis (Fig. 2)
b.
Acute Trabecular Microfractures (Fig. 7,Fig. 8,Fig. 9, Fig. 10,
Fig. 11)
c.
Stress Fatigue Fractures (Fig. 3)
d.
Stress Insufficiency Fractures
i.
SIF (Subchondral Insufficiency Fracture)formerly known...
Conclusion
Knee bone marrow edema is a very common finding on MRI scans.
However,
its pathophysiology it’s not as simple as one could imagine as there are several different mechanisms through which it can develop.
For each of these mechanisms there is a specific set of possible underlying diseases,
some with a very characteristic distribution pattern.
Having this knowledge is highly helpful in narrowing down differential diagnosis and not missing common associated injuries.
Personal information
José Saraiva 1
André Teixeira Gomes1
Carlos Bilreiro1
Ana Rita Ventosa1
Rodrigo Monteiro1
Bruno Santos1
Miguel Oliveira eCastro1
1.
Serviço de Radiologia
Centro Hospitalar e Universitário do Algarve
Largo do Poço Seco
8500-338 Portimão
PORTUGAL
References
1. Eustace S.
General principles.
In: Eustace S,
ed.
Magnetic Resonance Imaging of Orthopaedic Trauma.
Philadelphia,
PA: Lippincott Williams & Wilkins; 1999:60–65
2. O’Hare A.
et al,
Bone Marrow Edema: Patterns and Clinical Implications,
Semin Musculoskelet Radiol.
Thieme Medical Publishers,
Inc.,
2006;10:249–257.
3. Sanders .TG.
et al,
Bone Contusion Patterns of the Knee at MR Imaging: Footprint of the Mechanism of Injury, Radiographics,
2000.
20 Spec No: p.
S135-51
4. Helms C.A.
et al,
Musculoskeletal MRI,
2nd ed,
Philadelphia,
Pennsylvania,
Saunders-Elsevier, 2009,
ISBN: 978-14160-5534-1
5....