Non-invasive hepatic fat quantification: Can multi-echo Dixon help? / Quantificação da gordura hepática não invasiva: multieco Dixon pode ajudar?

Abstract Objective: To evaluate the diagnostic accuracy of multi-echo Dixon magnetic resonance imaging (MRI) in hepatic fat quantification, in comparison with that of magnetic resonance spectroscopy (MRS), on 3.0-T MRI. Materials and Methods: Fifty-five adults with no known liver disease underwent MRI in a 3.0-T scanner for determination of the hepatic fat fraction, with two techniques: multi-echo Dixon, in a manually drawn region of interest (ROI) and in the entire liver parenchyma (automated segmentation); and MRS. The diagnostic accuracy and cutoff value for multi-echo Dixon were determined, with MRS being used as the reference standard. Results: The mean fat fraction obtained by multi-echo Dixon in the manually drawn ROI and in the entire liver was 5.2 ± 5.8% and 6.6 ± 5.2%, respectively, whereas the mean hepatic fat fraction obtained by MRS was 5.7 ± 6.4%. A very strong positive correlation and good agreement were observed between MRS and multi-echo Dixon, for the ROI (r = 0.988, r2 = 0.978, p < 0.001) and for the entire liver parenchyma (r = 0.960, r2 = 0.922, p < 0.001). A moderate positive correlation was observed between the hepatic fat fraction and body mass index of the participants, regardless of the fat estimation technique employed. Conclusion: For hepatic fat quantification, multi-echo Dixon MRI demonstrated a very strong positive correlation and good agreement with MRS (often considered the gold-standard noninvasive technique). Because multi-echo Dixon MRI is more readily available than is MRS, it can be used as a rapid tool for hepatic fat quantification, especially when the hepatic fat distribution is not homogeneous.

Resumo Objetivo: Avaliar a acurácia diagnóstica da técnica multieco Dixon na quantificação da gordura hepática em comparação com a espectroscopia por ressonância magnética (ERM), em exames de RM 3.0-T. Materiais e Métodos: Cinquenta e cinco participantes adultos sem doença hepática conhecida foram submetidos a RM 3.0-T para determinação da fração de gordura hepática, usando duas técnicas: multieco Dixon (em ROI desenhada manualmente e em segmentação automatizada para todo o parênquima hepático) e ERM. A precisão diagnóstica e o valor de corte para multieco Dixon foram determinados usando a ERM como padrão de referência. Resultados: A fração de gordura média usando multieco Dixon na ROI desenhada manualmente e na segmentação automatizada do fígado inteiro foi 5,2 ± 5,8% e 6,6 ± 5,2%, respectivamente. A fração de gordura hepática média usando ERM foi 5,7 ± 6,4%. Correlação positiva muito alta e forte concordância foram observadas entre ERM e multieco Dixon, tanto para ROI (r = 0,988, r2 = 0,978, p < 0,001) quanto para todo o parênquima hepático (r = 0,960, r2 = 0,922, p < 0,001). Correlação positiva moderada foi observada entre a fração de gordura hepática e o índice de massa corpórea dos participantes usando ambas as técnicas de estimativa de gordura. Conclusão: Multieco Dixon demonstrou correlação positiva muito alta e concordância com a ERM (muitas vezes considerada padrão de referência não invasivo) para quantificação de gordura hepática. Uma vez que o multieco Dixon está mais prontamente disponível do que a ERM, pode ser usado como uma ferramenta rápida para a quantificação da gordura hepática, especialmente na distribuição não homogênea da gordura.

Chondromyxoid Fibroma of Clavicle Presenting as Radiological Disappearance of Bone

Case?Presentation Chondromyxoid fibroma (CMF) is a relatively rare bone tumor of cartilaginous origin and it comprises less than 1% of all primary bony tumors. Clavicle is an unusual site of involvement for any bone tumor and may produce diagnostic dilemma. Approximately only 1% of all primary bone tumors may involve the clavicle. The literature on clinical features and outcome of CMF clavicle remains sparse. Conclusion?We present an unusual case of CMF clavicle in which the medial aspect of the clavicle gradually disappeared on radiographs. CMF should be included in the differential diagnoses of disappearing bone disease.

Tectocerebellar dysraphia and occipital encephalocele: an unusual association with abdominal situs inversus and congenital heart disease.

Tectocerebellar dysraphia is a rare constellation of malformations comprising of occipital encephalocele, aplasia of the cerebellar vermis and deformity of the tectum. We describe a 7 month old infant who presented with tectocerebellar dysraphia associated with double outlet right ventricle, pulmonary stenosis and abdominal situs inversus. This association has not been reported in the literature, to the best of our knowledge.

Infantile haemangio-endothelioma of liver: a case report.

Infantile haemangio-endothelioma of liver is the most common symptomatic vascular tumour of liver. A 6-month-old female was admitted for evaluation of a mass in the right hypochondrium. It extended 5 cm below the right costal margin. USG of the liver revealed multiple hypo-echoic lesions within the liver. Non-contrast CT images showed multiple hypo-attenuating masses of lower density than the surrounding liver. A postcontrast CT revealed intense enhancement of all the lesions. The findings suggested an infantile haemangio-endothelioma of the liver. On follow-up USG after 8 months near complete involution of the mass was revealed.

Moyamoya disease--magnetic resonance imaging and magnetic resonance angiographic features.

A rare case of moyamoya disease in a 9-year-old female presented with behavioural disturbances and recurrent hemiparetic attacks is reported. Moyamoya disease is an uncommon form of arteritis which affects the cerebrovascular circulation. Magnetic resonance angiography is a non-invasive technique for evaluation of the carotid and vertebrobasilar circulation. The magnetic resonance angiography findings are typical and characteristic of this disease.

Pantothenate kinase associated neurodegeneration (Hallervorden-Spatz syndrome).

Hallervorden-Spatz syndrome is a rare autosomal recessive hereditary condition characterized by early onset of progressive movement alteration that include dystonia, rigidity and choreoathetosis usually associated with pyramidal signs and mental deterioration. We report two sisters where diagnosis was missed till MRI showed classic imaging findings. Mutation analysis in one, revealed homozygous mutations in the PANK 2 gene. The need for clinical recognition of this entity and differentiation of this form from other static and progressive neurological illnesses is emphasized.