Evaluation of knee articular cartilage through calcium-suppressed technique in dual-energy computed tomography
Authors: Khanduri Sachin , Siddiqui Saim Ali , Dhingra Vibhor , Imam Tariq Ahmad , Jaiswal Vinima , Bansal Tanya , Shahnawaz  , Vasundhra  
Published: December 2024

Objectives:
The evaluation of knee articular cartilage is of paramount importance in diagnosing and managing musculoskeletal disorders. Accurate and non-invasive imaging techniques are essential for assessing cartilage health, guiding treatment decisions, and monitoring disease progression. The objective of this study is to assess the potential of a calcium-suppressed technique in dual-energy computed tomography (DECT) as a viable alternative to the gold standard magnetic resonance imaging (MRI) for the evaluation of knee articular cartilage. DECT is gaining momentum in musculoskeletal imaging due to its ability to differentiate tissues with high precision. By suppressing calcium signals in DECT, the cartilage can be visualized more effectively, providing valuable insights into its integrity and structural changes. This paper seeks to compare the diagnostic accuracy and overall performance of DECT with calcium suppression to conventional MRI. The findings of this research have the potential to revolutionize the way that we approach knee cartilage evaluation, making it more accessible and efficient for both clinicians and patients. This paper contributes to the ongoing efforts in advancing medical imaging and orthopedic diagnostics, ultimately improving patient outcomes and healthcare practices.

Material and Methods:
In this study, we included patients who had reported knee pain and were referred for both DECT and MRI examinations. To enhance cartilage visualization, calcium-suppressed images were generated through a specialized algorithm applied to spectral-based images and were then superimposed onto conventional computed tomography (CT) images for visual assessment. The structure and thickness of knee cartilage were meticulously examined, and measurements of articular cartilage thickness were taken from sagittal proton density-weighted images and calcium-suppressed images in at lateral femoral tibial, patella femoral, and medial femoral tibial region of knee.

Results:
The present study was done to compare the two diagnostic modalities (DECT and MRI) for assessment of cartilage thickness of patients with knee pain. Cartilage thickness was assessed at lateral femoral tibial, patella femoral, and medial femoral tibial region of knee. Cartilage thickness of only affected knee was assessed by DECT and MRI, which showed almost perfect agreement (differences non-significant) at all the regions: (Lateral femoral region 1.61 ± 0.55 mm vs. 1.62 ± 0.55; Patella femoral: 1.62 ± 0.70 vs. 1.65 ± 0.70 mm and Medial femoral tibial: 1.82 ± 0.78 vs. 1.86 ± 0.74 mm).

Conclusion:
This study showed that measurements of knee cartilage thickness by DECT were as reliable as that by MRI. This study compares DECT and MRI for assessing knee articular cartilage. The rationale for combining CT and MRI provides a comprehensive evaluation of bone and soft-tissue pathology, complex injuries, and pre-surgical planning. DECT excels in bone detail, while MRI excels in soft-tissue evaluation. Our findings suggest that DECT may replace MRI for cartilage thickness assessment and qualitative evaluation of knee abnormalities, offering a cost-effective alternative with improved accessibility and reduced contraindications. DECT benefits patients of knee pain with limited MRI access or with contraindications.