[Nontraumatic femoral head necrosis: classification of bone scintigraphic findings and diagnostic value of SPECT following planar imaging].

This study was conducted to determine bone scintigraphic findings in nontraumatic femoral head avascular necrosis and diagnostic value of SPECT imaging following a conventional planar imaging. Forty-three femoral heads in twenty-six cases with idiopathic femoral head necrosis (n = 2), systemic lupus erythematosus (n = 22), aplastic anemia (n = 1), and renal transplantation (n = 1) were studied. The diagnosis for femoral head necrosis was based on magnetic resonance imaging as well as other diagnostic studies in all cases. Scintigraphic findings of planar and SPECT images were classified into six categories: normal (N); cold or decrease (C); partial increase with cold or decrease (PH+C); ring-like increase with a cold center (RH+C); partial increase (PH); diffuse and/or irregular increase (DH). Avascular necrosis was confirmed in twenty-four femoral heads, in which planar and SPECT images showed scintigraphic findings of N (n = 3, 2), C (n = 1, 3), PH+C (n = 2, 8), RH+C (n = 2, 3), PH (n = 9, 2), and DH (n = 7, 6), respectively. Femoral heads without avascular necrosis demonstrated planar and SPECT findings of N (n = 16, 12), C (n = 0, 6), and DH (n = 3, 1), respectively. When considering C, PH+C, and RH+C as diagnostic findings for avascular necrosis, sensitivities of planar and SPECT images were 21% and 58%, and specificities were 100% and 68%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)