CT-based analysis of malignant tumor volume and localization: a preliminary study

Abstract

ABSTRACT:The purpose of this study was to correlate 3D-CT (3D computed tomography) volume measurements of malignant tumors with the response to treatment, and to observe bone invasion in these lesions applying a specific imaging protocol. We analyzed 17 individuals with maxillofacial malignant lesions who were submitted to spiral CT (2D-CT). The original data were transferred to an independent workstation using a 3D volume rendering package software, which was used by two examiners to obtain area and volume measurements of the lesions, independently, three times each, prior to and after treatment. The segmentation protocol was applied for the assessment of bone involvement. The difference between imaging and gold standard values was not considered significant (p > 0.05). Regarding bone invasion, three false-negatives were obtained using MPR-CT (multiplanar reconstruction) and no false-negatives were obtained using the 3D segmentation protocol. The use of 3D-CT may be a differential and important factor for expanding options regarding the localization, dimension, and clarification of lesion components. DESCRIPTORS: Tomography; Wounds and injuries; Image processing, computer-assisted; Face; Neoplasms. RESUMO:O propósito desta pesquisa foi correlacionar medidas volumétricas de lesões malignas em reconstruções tridimensionais (TC-3D) com a resposta ao tratamento e verificar o grau de envolvimento ósseo dessas lesões, aplicando-se protocolos de imagem específicos associados à computação gráfica. Foram estudados 17 indivíduos portadores de lesões malignas maxilofaciais que haviam sido submetidos à tomografia computadorizada espiral (TC-2D). Os dados originais foram transferidos para uma estação de trabalho independente, utilizando um programa para imagens volumétricas, com o qual dois observadores obtiveram medidas de área e volume das lesões, independentemente, 3 vezes cada um, no pré e pós-tratamento. O protocolo de segmentação foi aplicado para avaliação do comprometimento ósseo. A diferença entre os valores obtidos na análise da TC e no padrão ouro não foi considerada significante (p > 0,05). Considerando o envolvimento ósseo, obtiveram-se três falsos-negativos em análise das reconstruções multiplanares (TC-RMP) e nenhum falso-negativo em análise da TC-3D por meio do protocolo de segmentação. A utilização de recursos como reconstrução em TC-3D pode ser um fator diferencial e de grande valia para aumentar opções quanto a localização, dimensões e esclarecimento de componentes de diversas lesões.

Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions

“…[21][22][23] stated that for detailed evaluation of the mandible it is essential to obtain CT scans with bone windows and narrow cuts, and the accuracy found in his work was 68%. According to Baxter and Sorenson 21 , identification of the number of lesions was inaccurate when the diameter was comparable to or less than the CT slice thickness, not allowing a correct identification of bone lesions.…”

“…According to Baxter and Sorenson 21 , identification of the number of lesions was inaccurate when the diameter was comparable to or less than the CT slice thickness, not allowing a correct identification of bone lesions. Furthermore, Cavalcanti et al 22 demonstrated high false positive and false negative rates when determining mandibular bone invasion using 3-mm-thick axial slices. In the present work, using a 0.5 mm slice thickness with a thinner interval of reconstruction (0.3 mm) for MSCT and 0.25 mm voxel size for CBCT, 90.4% and 90.7% of sensitivity and 96.3% and 95.9% of specificity (median values) were found regarding the number of simulated lesions respectively.…”

Influence of dental metallic artifact from multislice CT in the assessment of simulated mandibular lesions

“…Many authors have discussed the importance of acquisition parameters as slice thickness in bone lesion evaluation 4,9,26 . Shaha 26 stated that for detailed evaluation of the mandible is essential to obtain the CT scans with bone windows and narrow cuts, since the accuracy found in his work was 68%, using a singleslice CT.…”

“…According to Baxter and Sorenson 4 , the number of lesions is inaccurate when the diameter is comparable to or less than the CT slice thickness 12 . Furthermore, Cavalcanti, et al 9 demonstrated a high false positive and false negative rates when determining bone invasion in mandible, because 3-mm-thick axial slices are used, and also most authors suggested that thin slices are needed to detect more bone details 4,9,26 .…”

Oral cleft volumetric assessment by 3D multislice computed tomographic images

“…After complete selection of the area of interest (in all the axial images), the 3D reconstruction was used for final visualisation of the anatomical structures ( Fig. 6), following the methodology used in previous studies 3,4,17 .…”