Application of Diffusion-Weighted Imaging in the Detection of Active Sacroiliitis and the Comparison of Apparent Diffusion Coefficient and Relative Apparent Diffusion Coefficient Values

Abstract

Objectives: This study aims to evaluate the role of diffusion-weighted imaging in detection of active sacroiliitis and compare the apparent diffusion coefficient (ADC) and normalized relative ADC (r-ADC) values by using vertebra and iliac wings as reference organs. Patients and methods:The study included 56 patients (26 males, 30 females; mean age 37.7±10.1 years; range 18 to 66 years) with chronic back pain and without history of sacroiliitis who underwent magnetic resonance imaging. T2-weighted spectral presaturation with inversion recovery, contrast-enhanced T1-weighted spectral presaturation with inversion recovery, and diffusion-weighted (b values: 0 and 600 s/mm 2 ) images were obtained. All images were evaluated by two different radiologists for interobserver variability. All individuals were grouped in either mechanical low back pain (control group) or active sacroilitis (disease group) groups according to the presence or absence of MRI findings of active sacroilitis. ADC values of both surfaces were measured from normal and affected areas of joints. Also, ADC values of L5 vertebra and iliac wings were measured as reference organs to calculate r-ADC values. Results: Mean ADC and r-ADC values measured from lesions were significantly higher than that of normal appearing bone marrow areas in both patients with mechanical low back pain (n=17) and active sacroiliitis (n=39). Both ADC values and r-ADC values could differentiate active lesions from normal appearing bone marrow areas as well as contrast-enhanced T1-weighted images. According to r-ADC values calculated with the L5 vertebra, unaffected portions of bone marrow areas in patients with sacroiliitis were normalized whereas r-ADC remained higher than normal in affected portions of the bones. Conclusion: Diffusion-weighted imaging is a fast, sensitive magnetic resonance imaging sequence in detection of active sacroiliitis. It does not require contrast agent and can be safely used as an adjunct to conventional magnetic resonance images. r-ADC is also highly sensitive in detecting active sacroiliitis and may be used as an alternative to standard ADC measurements for the demonstration of inflammation. It helps eliminate individual bone marrow differences by using patients' own normal bone marrow measurements and increases diagnostic accuracy.

Comparison of apparent diffusion coefficient and relative apparent diffusion coefficient values for differential diagnosis of breast lesions

“…Diffusion weighted imaging (DWI) based on the random and thermal (Brownian) motion of water which can be quantified by calculating apparent diffusion coefficient (ADC) values in square millimeter per second depending on the degree of water molecule diffusion at in vivo MRI [8][9][10][11][12]. ADC values obtained from DWI can be affected by menstrual cycle and hormone replacement therapy [16,17].…”

“…Hence the degree of tissue water diffusion is inversely associated with the cellularity of the tissue and the cell membrane integrity. Based on this phenomenon, DW-MRI can be used to evaluate many pathologic conditions in the body and can help differentiate cellularity of the histologic structure [8][9][10][11][12].…”

“…Diffusion is quantified by calculating what is known as the apparent diffusion coefficient (ADC) value in square millimeter per second, which describes the average area covered by a molecule per unit time. The ADC value can be calculated by assessing the signal attenuation that occurs at diffusion-weighted imaging performed at different b values [10][11][12].…”

The usefulness of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences visual assessment in the early diagnosis of axial spondyloarthritis

“…Of course, we cannot omit the fact that several previous authors reported the high relevance of quantitative assessment of ADC value in the differentiation of axSpA and non-inflammatory lesions [7,[18][19][20][21][22][23] as well as in the monitoring of axSpA treatment [8,24]. The mean ADC was higher in patients with an active axSpA in comparison to patients with low back pain of mechanical origin [20,21], Modic 1 changes in spine [22,23] and healthy individuals [18][19][20]. Furthermore, according to previous research, ADC value measured within the bone lesions correlates with C-related protein level [7], disease activity (BASDAI-Bath Ankylosing Spondylitis Disease Activity Index), functional impairment (BASFI-Bath Ankylosing Spondylitis Functional Index) and patient global assessment (BASGI-Bath Ankylosing Spondylitis Global Index) scores [25].…”

“…First of all, a reliable methodology of ADC value measurement should be developed and uniformed between the future studies. Currently, some authors perform a direct measurement of ADC value [7,18,20,21], while the others calculate the relative ADC value [10,19], referring it to an unaffected bone, for instance, in the midline of the sacral bone [10]. Additionally, in some reports, there is a comparison between ADC value within the inflammatory lesions and to the one measured within the unaffected bone [7,10,18,20,21], while in the others, mean ADC value from regions unaffected by bone marrow oedema or structural changes is globally assessed and compared between the sides and the groups with and without axSpA [19].…”