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Femoral head avascular necrosis: correlation of MR imaging, radiographic staging, radionuclide imaging, and clinical findings.
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1987
Year
Skeletal TraumaSpinal FractureCentral RegionBone ImagingMedical ImagingMusculoskeletal ImagingRadiographic StagingMr ImagesMagnetic ResonanceOsteoarthritisMr ImagingSurgeryOsteoporosisRadionuclide ImagingMedicineOrthopaedic SurgeryRadiologyHealth Sciences
The study aimed to correlate femoral head avascular necrosis appearance on MRI with disease stage by comparing 56 MR images to radiographic staging, Tc‑99m scans, and symptom severity, and to present a chronological MR signal pattern that could aid staging. Researchers compared MRI findings of 56 confirmed AVN lesions with corresponding radiographic stages, Tc‑99m scans, and symptom grades to assess correlation. They found fractures in 50% of advanced radiographic stages, a characteristic double‑line sign in 80% of lesions, isointense central signal in 71% of early stages but only 14% of advanced stages, and a correlation between low‑signal central regions and more severe symptoms, suggesting that double‑line and central signal patterns may improve MRI‑based staging of AVN.
To better correlate the appearance of avascular necrosis (AVN) of the femoral head on magnetic resonance (MR) images with the stage of disease, MR images of 56 proved AVN lesions were compared with staging from corresponding radiographs (n = 56), Tc-99m scans (n = 41), and grade of symptoms (n = 28). Fractures complicating AVN were seen in 28 (50%) of 56 radiographs (radiographic stages III-V). With long repetition (TR) and echo delay (TE) times, a characteristic "double line sign" consisting of high signal intensity inside a low-intensity peripheral rim was seen in 45 lesions (80%). The central region within the rim was isointense with marrow fat on both short and long TR and TE images in 20 (71%) of 28 lesions uncomplicated by fracture (stages I-II) but in only four (14%) of 28 stage III-V lesions (P less than .001). Symptoms were least severe in lesions isointense with fat and most severe in lesions with low-signal central regions at short and long TRs and TEs. The peripheral double line sign on long TR/TE images may add specificity to the diagnosis of AVN by MR imaging. A chronologic pattern of central MR signal features is presented which may allow staging of AVN by MR imaging.