Nihal Martis1, Philippe Viau2, Thierry Zenone3, Fanny Andry4, Aurélie Grados5, Mikael Ebbo5, Emeline Castela6, Benoit Brihaye7, Eric Denis8, Stéphane Liguori9, Alexandra Audemard10, Yoland Schoindre11, Anne-Sophie Morin12, Benjamin Terrier13, Laurent Marcq8, Nicolas Mounier14, Olivier Lidove15, Jean-Philippe Chaborel16, Denis Quinsat8. 1. Service de Médecine Interne, CHU de Nice, Université Côte d'Azur, Faculté de Médecine de Nice, Nice, France. martis.n@chu-nice.fr. 2. Service de Médecine Nucléaire, CHU de Nice, Université Côte d'Azur, Faculté de Médecine de Nice, Nice, France. 3. Service de Médecine Interne, CH de Valence, Valence, France. 4. Service de Médecine Interne, CHU Michallon, Grenoble, France. 5. Service de Médecine Interne, Hôpital La Timone, AP-HM, Marseille, France. 6. Service de Médecine Interne, CHU de Nice, Université Côte d'Azur, Faculté de Médecine de Nice, Nice, France. 7. Service de Médecine Interne, CH Saint-Quentin, Saint-Quentin, France. 8. Service de Médecine Interne, CH d'Antibes-Juan-les-Pins, Antibes, France. 9. Service de Biologie Médicale, CH d'Antibes-Juan-les-Pins, Antibes, France. 10. Service de Médecine Interne, CHU de Caen, Caen, France. 11. Service de Médecine Interne, Hôpital de la Pitié Salpêtrière, AP-HP, Paris, France. 12. Service de Médecine Interne, Hôpital Jean Verdier, AP-HP, Bondy, France. 13. Service de Médecine Interne, Hôpital Cochin, AP-HP, Paris, France. 14. Service d'Onco-Hématologie, CHU de Nice, Université Côte d'Azur, Faculté de Médecine de Nice, Nice, France. 15. Service de Médecine Interne, CH Croix St-Simon, Paris, France. 16. Service de Médecine Nucléaire, Institut Tzanck Mougins, Mougins, France.
Abstract
OBJECTIVE: To study a muscle-to-muscle standardised uptake value (SUV) ratio with FDG-PET/CT (FDG-PET) as a marker for the detection of disease activity in dermatomyositis (DM). METHODS: Patients with DM (n = 24) who met the European Neuro-Muscular Centre diagnostic criteria were retrospectively identified over a 3-year period through a national survey. Muscle biopsy was performed in all patients. Maximum SUV was measured in proximal muscles (SUVPROX) that had the highest radiotracer uptake on visual grading as well as in the musculus longissimus thoracis (SUVMLT), whereas mean SUV was measured for the liver (SUVLIV). Muscle-to-liver SUV ratios for either muscle group were compared and a SUVPROX/SUVMLT ratio was calculated. SUVPROX/SUVMLT of DM patients were compared with age- and sex-matched control subjects (n = 24) with melanoma who had received FDG-PET scans. RESULTS: DM patients presented with proximal and symmetrical muscle uptake. Differences in SUVPROX/SUVLIV and SUVMLT/SUVLIV ratios in DM subjects were significant (p < 0.001). SUVPROX/SUVMLT ratios in DM and their controls also differed significantly (p = 0.0012). The SUVPROX/SUVMLT ratio threshold between DM subjects and controls was 1.73 with a sensitivity of 50% (CI95%, 29.1 to 70.9%) and specificity at 83.3% (CI95%, 62.6 to 95.3%). When amyopathic DM patients were removed from the analysis, specificity was increased to 95% (CI95%, 75.1 to 99.9%) with a likelihood ratio of 10 and an AUC of 83.4% (CI95%, 71.4 to 95.4%). CONCLUSION: A muscle-to-muscle SUVPROX/SUVMLT ratio with a cut-off value of 1.73 in FDG-PET imaging might serve as a non-invasive marker to determine disease activity in dermatomyositis. KEY POINTS: • [18F]-FDG PET-scanner standardised uptake value (SUV) could reflect disease activity in dermatomyositis (DM). • A ratio of SUV in proximal muscles (SUVPROX) to SUV in musculus longissimus thoracis (SUVMLT) could be used to determine active DM. • Active disease is suspected for SUV PROX /SUV MLT ratios greater than 1.73.
OBJECTIVE: To study a muscle-to-muscle standardised uptake value (SUV) ratio with FDG-PET/CT (FDG-PET) as a marker for the detection of disease activity in dermatomyositis (DM). METHODS:Patients with DM (n = 24) who met the European Neuro-Muscular Centre diagnostic criteria were retrospectively identified over a 3-year period through a national survey. Muscle biopsy was performed in all patients. Maximum SUV was measured in proximal muscles (SUVPROX) that had the highest radiotracer uptake on visual grading as well as in the musculus longissimus thoracis (SUVMLT), whereas mean SUV was measured for the liver (SUVLIV). Muscle-to-liver SUV ratios for either muscle group were compared and a SUVPROX/SUVMLT ratio was calculated. SUVPROX/SUVMLT of DMpatients were compared with age- and sex-matched control subjects (n = 24) with melanoma who had received FDG-PET scans. RESULTS:DMpatients presented with proximal and symmetrical muscle uptake. Differences in SUVPROX/SUVLIV and SUVMLT/SUVLIV ratios in DM subjects were significant (p < 0.001). SUVPROX/SUVMLT ratios in DM and their controls also differed significantly (p = 0.0012). The SUVPROX/SUVMLT ratio threshold between DM subjects and controls was 1.73 with a sensitivity of 50% (CI95%, 29.1 to 70.9%) and specificity at 83.3% (CI95%, 62.6 to 95.3%). When amyopathic DMpatients were removed from the analysis, specificity was increased to 95% (CI95%, 75.1 to 99.9%) with a likelihood ratio of 10 and an AUC of 83.4% (CI95%, 71.4 to 95.4%). CONCLUSION: A muscle-to-muscle SUVPROX/SUVMLT ratio with a cut-off value of 1.73 in FDG-PET imaging might serve as a non-invasive marker to determine disease activity in dermatomyositis. KEY POINTS: • [18F]-FDG PET-scanner standardised uptake value (SUV) could reflect disease activity in dermatomyositis (DM). • A ratio of SUV in proximal muscles (SUVPROX) to SUV in musculus longissimus thoracis (SUVMLT) could be used to determine active DM. • Active disease is suspected for SUV PROX /SUV MLT ratios greater than 1.73.
Authors: Janneke Van De Vlekkert; Mario Maas; Jessica E Hoogendijk; Marianne De Visser; Ivo N Van Schaik Journal: Muscle Nerve Date: 2015-02 Impact factor: 3.217