MRI of diffuse-type tenosynovial giant cell tumour in the knee: a guide for diagnosis and treatment response assessment.

Tenosynovial giant cell tumour (TGCT) is a rare soft-tissue tumour originating from synovial lining of joints, bursae and tendon sheaths. The tumour comprises two subtypes: the localised-type (L-TGCT) is characterised by a single, well-defined lesion, whereas the diffuse-type (D-TGCT) consists of multiple lesions without clear margins. D-TGCT was previously known as pigmented villonodular synovitis. Although benign, TGCT can behave locally aggressive, especially the diffuse-type. Magnetic resonance imaging (MRI) is the modality of choice to diagnose TGCT and discriminate between subtypes. MRI can also provide a preoperative map before synovectomy, the mainstay of treatment. Finally, since the arrival of colony-stimulating factor 1-receptor inhibitors, a novel systemic therapy for D-TGCT patients with relapsed or inoperable disease, MRI is key in assessing treatment response. As recurrence after treatment of D-TGCT occurs more often than in L-TGCT, follow-up imaging plays an important role in D-TGCT. Reading follow-up MRIs of these diffuse synovial tumours may be a daunting task. Therefore, this educational review focuses on MRI findings in D-TGCT of the knee, which represents the most involved joint site (approximately 70% of patients). We aim to provide a systematic approach to assess the knee synovial recesses, highlight D-TGCT imaging findings, and combine these into a structured report. In addition, differential diagnoses mimicking D-TGCT, potential pitfalls and evaluation of tumour response following systemic therapies are discussed. Finally, we propose automated volumetric quantification of D-TGCT as the next step in quantitative treatment response assessment as an alternative to current radiological assessment criteria.

Evaluación de la estadificación inicial y la respuesta final al tratamiento de los pacientes con linfoma difuso de célula grande B con la tomografía computarizada de 64 detectores frente a la 18FDG tomografía por emisión de positrones/tomografía computarizada / Evaluation of diffuse large B-cell lymphoma patients with 64-slice multidetector computed tomography versus 18FDG positron emission tomography/computed tomography in initial staging and restaging after treatment

Fundamento y objetivos: Comparar prospectivamente la exactitud diagnóstica de la tomografía computarizada de 64 detectores (TCMD64) y la tomografía por emisión de positrones/tomografía computarizada (18FDG PET/TC) con contraste intravenoso en pacientes con linfoma difuso de células grandes B (LDCGB) en la estadificación inicial y en la evaluación de la respuesta al final del tratamiento. Material y métodos: Ensayo clínico controlado multicéntrico que incluyó 72 pacientes de 5 hospitales de la Comunidad de Madrid entre enero de 2012 y junio de 2015, aleatorizados de forma ciega a una diferente prueba de imagen inicial y final, 36 a 18FDG PET/TC y 36 a TCMD64. Un médico nuclear y un radiólogo interpretaron la 18FDG PET/TC de manera independiente, llegando a un consenso post-hoc. Por otro lado, un radiólogo ajeno interpretó la TCMD64 por separado. El patrón de referencia incluyó datos clínicos, pruebas complementarias y seguimiento. El Comité Ético de cada hospital aprobó el estudio y los sujetos firmaron su consentimiento por escrito. Resultados: Se observó buena concordancia de ambas pruebas diagnósticas con el patrón de referencia en la estadificación inicial (18FDG PET/CT [k=0,5] y TCMD64 [k=0,6]), existiendo solo buena concordancia en la evaluación de la respuesta al final del tratamiento con la 18FDG PET/TC (k=0,7). Conclusión: En la estadificación inicial de pacientes con LDCGB existe un grado de acuerdo satisfactorio de la 18FDG PET/TC y la TCMD64 con el patrón de referencia, mientras que en la evaluación de la respuesta al final del tratamiento la 18FDG PET/TC es superior a la TCMD64

Background and objectives: To prospectively compare the accuracy in initial staging and end-of-treatment restaging of diffuse large B-cell lymphoma (DLBCL) between 64-slice multidetector computed tomography (64MDCT) and 18FDG positron emission tomography/computed tomography (18FGD PET/CT) with intravenous contrast injection. Material and methods: Randomised and blind controlled clinical multicentric trial that included biopsy-proven DLBCL patients. Seventy-two patients from five different hospitals in the region of Madrid, Spain, were enrolled in the study between January 2012 and June 2015. Thirty-six were randomly allocated to 18FDG PET/TC and the other 36 to 64MDCT for initial staging and end-of-treatment restaging. A nuclear medicine physician and a radiologist independently analysed 18FDG PET/TC images and reached an agreement post-hoc. 64MDCT images were separately evaluated by a different radiologist. Every set of images was compared to the reference standard that included clinical data, complementary tests and follow-up. The study was approved by participating centres’ ethics committees and written informed consent was obtained from all the participants. Results: A good agreement was observed between both diagnostic techniques and the reference standard in initial staging [18FDG PET/CT (k=0.5) and 64MDCT (k=0.6)], although only the 18FDG PET/TC showed a good agreement with the reference standard for the end-of-treatment restaging (k=0.7). Conclusion: In DLBCL, both 18FDG PET/TC and 64MDCT have shown good agreement with the reference standard in initial staging. Nevertheless, 18FDG PET/CT has shown to be superior to 64MDCT in end-of-treatment response assessment

Evaluation of diffuse large B-cell lymphoma patients with 64-slice multidetector computed tomography versus 18FDG positron emission tomography/computed tomography in initial staging and restaging after treatment. / Evaluación de la estadificación inicial y la respuesta final al tratamiento de los pacientes con linfoma difuso de célula grande B con la tomografía computarizada de 64 detectores frente a la 18FDG tomografía por emisión de positrones/tomografía computarizada.

BACKGROUND AND OBJECTIVES: To prospectively compare the accuracy in initial staging and end-of-treatment restaging of diffuse large B-cell lymphoma (DLBCL) between 64-slice multidetector computed tomography (64MDCT) and 18FDG positron emission tomography/computed tomography (18FGD PET/CT) with intravenous contrast injection. MATERIAL AND METHODS: Randomised and blind controlled clinical multicentric trial that included biopsy-proven DLBCL patients. Seventy-two patients from five different hospitals in the region of Madrid, Spain, were enrolled in the study between January 2012 and June 2015. Thirty-six were randomly allocated to 18FDG PET/TC and the other 36 to 64MDCT for initial staging and end-of-treatment restaging. A nuclear medicine physician and a radiologist independently analysed 18FDG PET/TC images and reached an agreement post-hoc. 64MDCT images were separately evaluated by a different radiologist. Every set of images was compared to the reference standard that included clinical data, complementary tests and follow-up. The study was approved by participating centres' ethics committees and written informed consent was obtained from all the participants. RESULTS: A good agreement was observed between both diagnostic techniques and the reference standard in initial staging [18FDG PET/CT (k=0.5) and 64MDCT (k=0.6)], although only the 18FDG PET/TC showed a good agreement with the reference standard for the end-of-treatment restaging (k=0.7). CONCLUSION: In DLBCL, both 18FDG PET/TC and 64MDCT have shown good agreement with the reference standard in initial staging. Nevertheless, 18FDG PET/CT has shown to be superior to 64MDCT in end-of-treatment response assessment.