RESUMO
BACKGROUND: Iodine-123-metaiodobenzylguanidine (123I-MIBG) imaging with estimation of the heart-to-mediastinum ratio (HMR) has been established for risk assessment in patients with chronic heart failure. Our aim was to evaluate the effect of different methods of ROI definition on the renderability of HMR to normal or decreased sympathetic innervation. METHODS AND RESULTS: The results of three different methods of ROI definition (clinical routine (CLI), simple standardization (STA), and semi-automated (AUT) were compared. Ranges of 95% limits of agreement (LoA) of inter-observer variabilities were 0.28 and 0.13 for STA and AUT, respectively. Considering a HMR of 1.60 as the lower limit of normal, 13 of 32 (41%) for method STA and 5 of 32 (16%) for method AUT of all HMR measurements could not be classified to normal or pathologic. Ranges of 95% LoA of inter-method variabilities were 0.72 for CLI vs AUT, 0.65 for CLI vs STA, and 0.31 for STA vs AUT. CONCLUSION: Different methods of ROI definition result in different ranges of the LoA of the measured HMR with relevance for rendering the results to normal or pathological innervation. We could demonstrate that standardized protocols can help keep methodological variabilities limited, narrowing the gray zone of renderability.
Assuntos
3-Iodobenzilguanidina/química , Coração/diagnóstico por imagem , Coração/inervação , Mediastino/diagnóstico por imagem , Idoso , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reconhecimento Automatizado de Padrão , Cintilografia , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Processamento de Sinais Assistido por Computador , Sistema Nervoso SimpáticoRESUMO
PURPOSE: To determine the detection rate of PET/CT in biochemical relapse of prostate cancer using [68Ga]PSMA I&T and to compare it with published detection rates of [68Ga]PSMA HBED-CC. METHODS: We performed a retrospective analysis in 83 consecutive patients with documented biochemical relapse after prostatectomy. All patients underwent whole body [68Ga]PSMA I&T PET/CT. PET/CT images were evaluated for presence of local recurrence, lymph node metastases, and distant metastases. Proportions of positive PET/CT results were calculated for six subgroups with increasing prostate specific antigen (PSA) levels (<0.5 ng/mL, 0.5 to <1.0 ng/mL, 1.0 to <2.0 ng/mL, 2.0 to <5.0 ng/mL, 5.0 to <10.0, ≥10.0 ng/mL). Detection rates of [68Ga]PSMA I&T were statistically compared with published detection rates of [68Ga]PSMA HBED-CC using exact Fisher's test. RESULTS: Median PSA was 0.81 (range: 0.01 - 128) ng/mL. In 58/83 patients (70 %) at least one [68Ga]PSMA I&T positive lesion was detected. Local recurrent cancer was present in 18 patients (22 %), lymph node metastases in 29 patients (35 %), and distant metastases in 15 patients (18 %). The tumor detection rate was positively correlated with PSA levels, resulting in detection rates of 52 % (<0.5 ng/mL), 55 % (0.5 to <1.0 ng/mL), 70 % (1.0 to <2.0 ng/mL), 93 % (2.0 to <5.0 ng/mL), 100 % (5.0 to <10.0 ng/mL), and 100 % (≥10.0 ng/mL). There was no significant difference between the detection rate of [68Ga]PSMA I&T and published detection rates of [68Ga]PSMA HBED-CC (all p>0.05). CONCLUSIONS: [68Ga]PSMA I&T PET/CT has high detection rates of recurrent prostate cancer that are comparable to [68Ga]PSMA HBED-CC.
