Added value of SPECT/spiral CT versus SPECT or CT alone in diagnosing solitary skeletal lesions

Summary

Aim: The aim of this study was to investigate the added value of SPECT/spiral CT versus SPECT or CT alone in the differential diagnosis of solitary skeletal lesions.Methods: This was a retrospective study on a total of 69 patients who had a solitary skeletal “hot spot” that could not be definitively diagnosed using planar scintigraphy. Thus, SPECT/ spiral CT was performed on the indeterminate lesions. SPECT, CT and SPECT/spiral CT images were independently interpreted by two experienced doctors who have both identification of CT and nuclear medicine. Each lesion was graded on a 4-point diagnostic scale (1: benign, 2: likely benign, 3: likely malignant, 4: malignant). The final diagnosis of each lesion was based on pathological confirmation after surgery within 3 weeks of the bone scan.Results: Final diagnoses based on the pathological results revealed that 43 of the 69 patients were diagnosed with malignancy, and the remaining 26 patients were diagnosed as having benign lesions. For SPECT and CT scans, both of the reviewers rated 55.1% (38/69) and 37.7 % (26/69) of lesions as equivocal, with the help of SPECT/CT, 33.3 % (23/69) of lesions were rated as equivocal. The diagnostic accuracies of SPECT, CT alone and SPECT/CT were 66.7 % (46/69),82.6 % (57/69) and 85.5 %(59/69), respectively. The kappa scores for the degree of agreement between SPECT, CT alone or SPECT/CT with pathological results were 0.185 (p = 0.054), 0.612 (p < 0.001) and 0.671 (p < 0.001), respectively.Conclusion: Compared with SPECT or imaging alone, SPECT/ spiral CT imaging was more accurate and valuable in the differential diagnosis of solitary skeletal lesions and resulted in significantly fewer equivocal findings.

Zusammenfassung

Ziel: In dieser Studie sollte der Zusatznutzen der SPECT/Spiral-CT gegenüber SPECT oder CT alleine für die Differenzialdiagnose solitärer Skelettläsionen untersucht werden.Methoden: An der retrospektiven Studie nahmen insgesamt 69 Patienten mit einem solitären „Hot Spot” im Skelett teil, der mittels planarer Szintigraphie nicht abschließend diagnostiziert werden konnte. Daher wurden die unklaren Läsionen mittels SPECT/Spiral-CT dargestellt. Die SPECT-, CT- und Spiral-CT-Auf- nahmen wurden von zwei erfahrenen Ärzten mit Qualifikationen in CT und Nuklearmedizin unabhängig voneinander befundet. Jede Läsion wurde mit einer diagnostischen 4-Punkte-Skala klassifiziert (1: gutartig; 2: wahrscheinlich gutartig; 3: wahrscheinlich bösartig; 4: bösartig). Die Läsionen wurden innerhalb von 3 Wochen nach den Skelettaufnahmen operativ entfernt und anhand der pathologischen Beurteilung endgültig diagnostiziert.Ergebnisse: Als endgültige Diagnose auf der Basis der pathologischen Ergebnisse ergab sich bei 43 der 69 Patienten ein maligner Befund, bei den verbleibenden 26 Patienten wurden die Läsionen als benigne diagnostiziert. In den SPECT- bzw. CT-Aufnahmen beurteilten beide Gutachter 55,1 % (38/69) und 37,7 % (26/69) der Läsionen als nicht eindeutig, mithilfe des SPECT/Spiral-CT waren noch 33,3 % (23/69) der Läsionen unklar. Die diagnostische Genauigkeit von SPECT oder CT alleine und SPECT/CT lag bei 66,7 % (46/69), 82,6 % (57/69) bzw. 85,5 % (59/69). Die KappaScores als Maß für die Übereinstimmung von SPECT und CT alleine bzw. SPECT/CT mit den pathologischen Befunden waren jeweils 0,185 (p = 0.054), 0,612 (p < 0,001) und 0,671 (p < 0,001).Schlussfolgerung: Die Darstellung mittels SPECT/Spiral-CT lieferte für die Differenzialdiagnose solitärer Skelettläsionen genauere und wertvollere Ergebnisse als SPECT oder Bildgebung alleine sowie signifikant weniger unklare Befunde.”

Keywords

Solitary skeletal lesions - benign - malignant - SPECT/spiral CT

Schlüsselwörter

Solitäre Skelettläsionen - benigne - maligne - SPECT/Spiral-CT

^* These authors contributed equally.

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