Cinematic rendering for three-dimensional reconstructions of the chest wall: a new reality / Uma nova realidade: renderização cinematográfica para reconstruções tridimensionais da parede torácica

ABSTRACT Computed tomography with multiple detectors and the advancement of processors improved rendered images and three-dimensional reconstructions in clinical practice. Traditional axial slices form non-intuitive images because they are seen in only one plane. The three-dimensional reconstructions can show structures details and diseases with complex anatomy in different perspectives. Cinematic rendering is a newly three-dimensional reconstruction technique, already approved for clinical use, which can produce realistic images from traditional computed tomography data. The algorithm used is based on light trajectory methods and the global lighting model, which simulate thousands of images from all possible directions. Thus, the technique shapes the physical propagation of light and generates a realistic three-dimensional image with depth, shadows and more anatomic details. It is a multidimensional rendering acquired through complex lighting effects. The aim of this article was to show the advance of three-dimensional technology with the cinematic rendering in images exams of the thoracic wall.

RESUMO A tomografia computadorizada com os múltiplos detectores e o avanço dos processadores melhoraram as imagens renderizadas e as reconstruções tridimensionais na prática clínica. Os cortes axiais tradicionais formam imagens não intuitivas, pois são vistas em apenas um plano. Já as reconstruções tridimensionais podem exibir detalhes anatômicos em diferentes perspectivas das estruturas e de doenças com anatomia complexa. A renderização cinematográfica é uma técnica de reconstrução tridimensional recentemente introduzida, já aprovada para uso clínico, que pode produzir imagens realistas a partir de dados tradicionais da tomografia computadorizada. O algoritmo usado é baseado em métodos de trajetória da luz e no modelo de iluminação global, os quais simulam milhares de imagens de todas as direções possíveis. Assim, a técnica molda a propagação física da luz e gera uma imagem tridimensional realista, com profundidade, sombras e mais detalhes da alteração anatômica. É uma renderização multidimensional adquirida por efeitos de iluminação complexos. O objetivo deste artigo foi mostrar o avanço da tecnologia tridimensional com a renderização cinematográfica nos dos exames de imagens da parede torácica.

Thoracic calcifications on magnetic resonance imaging: correlations with computed tomography / Calcificações torácicas na ressonância magnética: correlações com a tomografia computadorizada

ABSTRACT Objective: To identify the characteristics of thoracic calcifications on magnetic resonance (MR) imaging, as well as correlations between MR imaging and CT findings. Methods: This was a retrospective study including data on 62 patients undergoing CT scans and MR imaging of the chest at any of seven hospitals in the Brazilian states of Rio Grande do Sul, São Paulo, and Rio de Janeiro between March of 2014 and June of 2016 and presenting with calcifications on CT scans. T1- and T2-weighted MR images (T1- and T2-WIs) were semiquantitatively analyzed, and the lesion-to-muscle signal intensity ratio (LMSIR) was estimated. Differences between neoplastic and non-neoplastic lesions were analyzed. Results: Eighty-four calcified lesions were analyzed. Mean lesion density on CT was 367 ± 435 HU. Median LMSIRs on T1- and T2-WIs were 0.4 (interquartile range [IQR], 0.1-0.7) and 0.2 (IQR, 0.0-0.7), respectively. Most of the lesions were hypointense on T1- and T2-WIs (n = 52 [61.9%] and n = 39 [46.4%], respectively). In addition, 19 (22.6%) were undetectable on T1-WIs (LMSIR = 0) and 36 (42.9%) were undetectable on T2-WIs (LMSIR = 0). Finally, 15.5% were hyperintense on T1-WIs and 9.5% were hyperintense on T2-WIs. Median LMSIR was significantly higher for neoplastic lesions than for non-neoplastic lesions. There was a very weak and statistically insignificant negative correlation between lesion density on CT and the following variables: signal intensity on T1-WIs, LMSIR on T1-WIs, and signal intensity on T2-WIs (r = −0.13, p = 0.24; r = −0.18, p = 0.10; and r = −0.16, p = 0.16, respectively). Lesion density on CT was weakly but significantly correlated with LMSIR on T2-WIs (r = −0.29, p < 0.05). Conclusions: Thoracic calcifications have variable signal intensity on T1- and T2-weighted MR images, sometimes appearing hyperintense. Lesion density on CT appears to correlate negatively with lesion signal intensity on MR images.

RESUMO Objetivo: Identificar as características das calcificações torácicas na ressonância magnética (RM) e as correlações entre os achados de RM e TC. Métodos: Estudo retrospectivo no qual foram analisados dados referentes a 62 pacientes que foram submetidos a TC e RM de tórax em sete hospitais nos estados do Rio Grande do Sul, São Paulo e Rio de Janeiro entre março de 2014 e junho de 2016 e que apresentaram calcificações na TC. As imagens de RM ponderadas em T1 e T2 (doravante denominadas T1 e T2) foram analisadas semiquantitativamente, e a razão entre a intensidade do sinal da lesão e do músculo (LMSIR, do inglês lesion-to-muscle signal intensity ratio) foi estimada. Diferenças entre lesões neoplásicas e não neoplásicas foram analisadas. Resultados: Foram analisadas 84 lesões calcificadas. A média de densidade das lesões na TC foi de 367 ± 435 UH. A mediana da LMSIR foi de 0,4 [intervalo interquartil (II): 0,1-0,7] em T1 e 0,2 (II: 0,0-0,7) em T2. A maioria das lesões mostrou-se hipointensa em T1 e T2 [n = 52 (61,9%) e n = 39 (46,4%), respectivamente]. Além disso, 19 (22,6%) foram indetectáveis em T1 (LMSIR = 0) e 36 (42,9%) foram indetectáveis em T2 (LMSIR = 0). Finalmente, 15,5% mostraram-se hiperintensas em T1 e 9,5% mostraram-se hiperintensas em T2. A mediana da LMSIR foi significativamente maior nas lesões neoplásicas do que nas não neoplásicas. Houve uma correlação negativa muito fraca e estatisticamente insignificante entre a densidade das lesões na TC e as seguintes variáveis: intensidade do sinal em T1, LMSIR em T1 e intensidade do sinal em T2 (r = −0,13, p = 0,24; r = −0,18, p = 0,10 e r = −0,16, p = 0,16, respectivamente). A densidade das lesões na TC apresentou correlação fraca, porém significativa com a LMSIR em T2 (r = −0,29, p < 0,05). Conclusões: As calcificações torácicas apresentam intensidade de sinal variável em T1 e T2; em alguns casos, mostram-se hiperintensas. A densidade da lesão na TC aparentemente correlaciona-se negativamente com a intensidade do sinal da lesão na RM.

Mesenchymal hamartomas of the chest wall in infancy: radiologic and pathologic correlation

Mesenchymal hamartoma of the chest wall is a rare tumor with about 53 reported cases in the English literature. We reviewed six chest wall mesenchymal hamartomas in four patients, including two cases with multiple lesions, with specific focus on the radiologic and pathologic correlation. All cases occurred in neonates or infants with ages ranging from seven hours to seven months. They were diagnosed with plain chest radiographs (n=6), ultrasonography (n=2), chest CT scan (n=6), whole body bone scan (n=2) and MRI (n=3). All cases except a small one without cystic change showed the typical features of mesenchymal hamartoma radiographically and pathologically. Radiologically they were well-circumscribed masses with solid and cystic components with multiple fluid-fluid levels in association with single or multiple rib destruction or change. The CT scan showed the typical findings of chest wall hamartoma, and the MR showed heterogeneous signal intensities of the mass on T1- and T2-weighted images. The MR also revealed more concisely a secondary aneurysmal bone cyst formation with multiple fluid-fluid levels on the T2-weighted image. Microscopically, they showed alternating areas of cartilaginous islands and primitive appearing mesenchymal proliferation, which corresponded well with the solid component on the radiologic findings. The areas of bone formation and blood-filled cystic spaces matched the calcified or ossified densities and the cystic components, respectively. A small case without cystic change showed peculiar radiological and pathological findings resembling an osteochondroma. In conclusion, mesenchymal hamartoma of the chest wall in infancy is quite rare and sometimes can be misdiagnosed as malignancy due to the bone-destroying radiographic appearance and the highly cellular and mitotically active microscopic features, unless the radiologists and pathologists are aware of the characteristic clinical, radiological, and pathological findings. Imaging studies can usually make a correct diagnosis with good correlation to the pathologic findings.