Detection Of Bone Marrow Edema
Dual energy CT: detection of bone marrow edema
Introduction
Bone marrow edema (BME) is radiographically characterized by increased water signals in the bone marrow, as detected by ultrasound and magnetic resonance imaging (MRI). The underlying pathophysiology of the increased water signals is not fully clear yet. Some evidence states that it is likely the cause of increased leakage of bone marrow capillaries due to either a local change in the capillary permeability or an increase in hydrostatic transluminal pressure. The increased transluminal pressure might be the consequence of an increased blow flow to the capillaries or a decreased drainage by the venous circulation.Detection Of Bone Marrow Edema
Another hypothesis is that the increased water signal is merely the result of an increased vascularization of the affected area. The underlying causes for BME are very broad. Both inflammatory and non-inflammatory pathophysiological mechanisms are considered to be involved. Pathologies which may result in BME range from trauma to neoplasms. From these causes trauma is the most frequent and often the most likely cause of BME in an emergency setting. Detection Of Bone Marrow Edema
In addition, it could be stated that the reliable and accurate detection of BME could be of value in the diagnosis of this large range of diseases. BME can be a direct source for discomfort.(5) BME is frequently associated with pain which is likely the result of irritation and/or damage to nerves in the bone marrow due to the increased pressure, which is the result of the lack of elasticity of the surrounding bone. On top of this, BME is also considered a prognostic factor for the progression of the causal disease.
It is of major importance to discover the cause of BME, in order to prevent further progression of the underlying disease and to relieve pain and discomfort of the patient. For surgical treatment it is mandatory to know the exact localization of the bone marrow edema, to ensure that holes will be drilled in the right area for adequate decompression.(1) Since BME is not visible on X-ray or standard computed tomography, the current standard techniques for getting useful information are MRI and ultrasound.
Ultrasound, however, has the major disadvantage that it cannot be used to visualize the inside of bones. In a non-emergency setting MRI is the preferred imaging method because of its high accuracy. MRI, however, has some drawbacks. Due to the long examination times, patients must remain still for prolonged periods of time to ensure a usable result. For trauma patients, elderly patients and young children this is highly challenging; it quite frequently causes suboptimal imaging results.
In addition, in patients with contraindications for MRI, alternatives are scarce. And, finally, MRI is an expensive imaging technique, and waiting times are also relatively high. More recently, dual energy CT (DECT) was shown to be a promising alternative technique in the imaging of BME. DECT has been proven useful in the diagnosis and imaging of gout. Another advantage of DECT is the virtual non-calcium modus (VNCa). Detection Of Bone Marrow Edema
VNCa can filter out trabecular bone leaving an image of the bone marrow. It has been proven that this can be used to show BME. It is, however, still unknown what the optimal settings are to assess the BME using an DECT VNCa image. Different studies use different settings for acquisition and reconstruction. In this review we will compare the results of different studies to answer the question:What are the preferable settings for the assessment of BME in patients with bone marrow injuries using dual energy CT?
Stuk over DECT wat kort door de bocht, verder de voordelen over andere technieken uitwerken.MethodsThis systematic review was written following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The search for articles was done exclusively in PubMed. To select articles to answer the question presented in the introduction a search was constructed around the keywords “Dual energy CT” and “Bone marrow edema”.
To avoid missing relevant articles the search was elaborated using synonyms for the keywords and MeSH-terms (medical subject headings). The synonyms used are: “Dual energy CT”, “DECT” for dual energy CT and “bone bruise”, “bone bruises”, “bone marrow edema”, and “bone marrow oedema” for bone marrow edema.
Titles and abstracts of the articles that this search produced were screened to make a first selection of studies. Studies were excluded in this step for the following reasons: Firstly, if the full text of the article was not accessible. Secondly, letters, correspondence, responses and errata were excluded, as well as case reports and meta-analyses. Thirdly, if the study did not make use of dual-energy CT it was not included. Studies where the detection of BME was not the focus of the study were further examined to determine if they were still relevant enough to include, if not, they were excluded as well. And lastly, the selection of articles was limited to English studies. The bibliographies of the remaining articles were screened for additional articles that were missed by the conducted search.Detection Of Bone Marrow Edema
The full texts of the remaining studies were then assessed for eligibility. Records were included in this step based on the following criteria: Firstly, the study had to mention tube voltage, slice thickness and kernel used in the methods section. Secondly, the study had to use MRI as a reference standard to compare their DECT results to. And thirdly, sensitivity and specificity needed to be given as an outcome measure in the results section of the study. Studies that did not meet the given criteria were excluded.CAT and bias assessmentData collectionData itemsData summary and analysis protocol.
Results
The search in PubMed resulted in 49 articles. These articles were screened, and a selection was made based on the exclusion criteria described. After this first selection 19 were left. Screening of the bibliographies of the remaining articles resulted in the addition of 2 articles bringing the total after the first selection to 21 articles. The full texts of these articles were assessed for eligibility based on the criteria mentioned before. A total of 10 additional studies were excluded in this step bringing the finalized selection of articles to 11.Detection Of Bone Marrow Edema