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BACKGROUND: The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. OBJECTIVES: We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. METHODS: The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. RESULTS: At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. CONCLUSIONS: In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques.

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Background: The diagnostic accuracy of 64-slice MDCT in comparison with IVUS has been poorly described and is mainly restricted to reports analyzing segments with documented atherosclerotic plaques. Objectives: We compared 64-slice multidetector computed tomography (MDCT) with gray scale intravascular ultrasound (IVUS) for the evaluation of coronary lumen dimensions in the context of a comprehensive analysis, including segments with absent or mild disease. Methods: The 64-slice MDCT was performed within 72 h before the IVUS imaging, which was obtained for at least one coronary, regardless of the presence of luminal stenosis at angiography. A total of 21 patients were included, with 70 imaged vessels (total length 114.6 ± 38.3 mm per patient). A coronary plaque was diagnosed in segments with plaque burden > 40%. Results: At patient, vessel, and segment levels, average lumen area, minimal lumen area, and minimal lumen diameter were highly correlated between IVUS and 64-slice MDCT (p < 0.01). However, 64-slice MDCT tended to underestimate the lumen size with a relatively wide dispersion of the differences. The comparison between 64-slice MDCT and IVUS lumen measurements was not substantially affected by the presence or absence of an underlying plaque. In addition, 64-slice MDCT showed good global accuracy for the detection of IVUS parameters associated with flow-limiting lesions. Conclusions: In a comprehensive, multi-territory, and whole-artery analysis, the assessment of coronary lumen by 64-slice MDCT compared with coronary IVUS showed a good overall diagnostic ability, regardless of the presence or absence of underlying atherosclerotic plaques. .

Fundamento: A comparação do rigor diagnóstico da TCMD e da USIV foi pouco descrita, estando restrita principalmente a estudos que avaliaram segmentos com placas ateroscleróticas já documentadas. Objetivos: Este estudo objetiva avaliar o desempenho diagnóstico da tomografia computadorizada com 64 colunas de detectores (tomografia computadorizada multidetector- TCMD) e da ultrassonografia intravascular (USIV) em escala de cinza na verificação das dimensões da luz coronária, em um contexto mais amplo, incluindo também segmentos coronários sadios e com patologia leve. Métodos: A TCMD foi realizada em todos os pacientes antes da realização da USIV, com um intervalo < 72 horas entre os dois exames. Imagens de USIV foram obtidas de pelo menos uma coronária, independente da presença de estenose luminal durante a angiografia. Um total de 21 pacientes foram incluídos, com imagens de 70 vasos (comprimento total 114,6 ± 38.3 mm por paciente). Placas coronárias foram diagnosticada em segmentos com carga de placas > 40%. Resultados: Uma alta correlação entre as medidas de TCMD e USIV para área luminar média, área luminar mínima e diâmetro luminar mínimo foi encontrada no nível de paciente, vaso e segmento (p-valor < 0,01 para todas as correlações). A TCMD, no entanto, tendeu a subestimar o tamanho luminar com uma dispersão de diferenças relativamente ampla. A comparação entre as medidas da luz por TCMD e USIV não foi substancialmente afetada pela presença ou ausência de placa subjacente. Além disso, a TCMD mostrou boa precisão geral na detecção de parâmetros associados a lesões limitantes de fluxo. Conclusão: Em uma análise compreensiva e multi-focal da luz coronária, demonstramos bom desempenho diagnóstico da TCMD, quando comparada a USIV, independente da presença de placas ateroscleróticas adjacentes. .

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INTRODUÇÃO: Pouco se conhece sobre a comparação entre métodos de avaliação da placa aterosclerótica coronária, como a tomografia computadorizada com múltiplos detectores (TCMD) e o ultrassom intravascular com técnica de histologia virtual (HV). MÉTODO: Foram analisados prospectivamente os vasos coronários principais de 21 pacientes à TCMD e à HV. Cada vaso analisado foi dividido em subsegmentos de 4 mm (unidades básicas para a análise). Os subsegmentos foram pareados conforme sua localização axial. Os limites da luz e do vaso foram traçados à HV e à TCMD com o auxílio de programas específicos. A contribuição porcentual de cada componente da placa à HV e a razão necrose:cálcio foram quantificadas. A placa à TCMD foi avaliada por sua densidade radiológica em unidades Hounsfield (UH). RESULTADOS: Foram analisados 641 subsegmentos, obtidos de 70 vasos. A contribuição porcentual dos componentes à HV foi: fibroso = 64%; fibrolipídico = 20%; núcleo necrótico = 11%; cálcio denso = 5%; e razão necrose:cálcio = 5,1. A atenuação da placa à TCMD variou de 44 UH a 440 UH. Para a análise, as placas foram divididas em três grupos de tamanhos semelhantes, conforme a densidade da placa à TCMD (1º tercil: 44-128 UH, 2º tercil: 129-178 UH, e 3º tercil: 178-440 UH). Houve correlação inversa entre a razão necrose/cálcio à HV e densidade da placa à TCMD (1º tercil: 4,1, 2º tercil: 2,9, e 3º tercil: 2,3; P < 0,01) e relação direta entre o porcentual de cálcio denso à HV e a densidade da placa à TCMD (1º tercil: 1,5%, 2º tercil: 2,5%, e 3º tercil: 3,8%; P < 0,01). CONCLUSÃO: A densidade da placa aterosclerótica avaliada pela TCMD em tomógrafo de 64 colunas de detectores associa-se significativamente com a composição da placa à HV.

BACKGROUND: Little is known about the comparative results of coronary plaque assessment by multidetector computed tomography (MDCT) against the novel intravascular ultrasound virtual histology (IVUS-VH). METHOD: Threevessel IVUS-VH and MDCT were prospectively obtained from 21 patients. Each vessel was divided into 4-mm subsegments, which were used as the basic unit for analysis. The 4-mm subsegments were matched by their axial location. Lumen and outer vessel boundaries for IVUS-VH and for MDCT were traced by specific automatic softwares. The percent contribution of each IVUS-VH plaque tissue type and the ratio of necrotic tissue to calcium were quantified. The MDCT plaque was evaluated through its average density in Hounsfield units (HU). RESULTS: A total of 641 matched subsegments were computed from 70 vessels. Overall, the average IVUS-VH tissue composition was: fibrous = 64%; fibrofatty = 20%; necrotic tissue = 11%; dense calcium = 5%; and calcium/necrosis ratio = 5.1. MDCT average plaque attenuation ranged from 44 to 440 HU and was divided into three groups of similar size (1st tertile: 44-128 HU; 2nd tertile: 129-178 HU; 3rd tertile: 178-440 HU). There was an inverse correlation between IVUS-VH necrotic/ dense calcium ratio and MDCT plaque density (1st tertile: 4.1, 2nd tertile: 2.9, 3rd tertile: 2.3; P < 0.01) and a direct relationship between percent IVUS-VH dense calcium and MDCT plaque density (1st tertile: 1.5%, 2nd tertile: 2.5%, 3rd tertile: 3.8%; P < 0.01). CONCLUSION: Atherosclerotic plaque density evaluated by 64-MDCT significantly associates with plaque composition assessed by IVUS-VH.

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