Title:Comparison Between the Maximum Standard Uptake Value and the Ratio of Lymph Node to Primary Tumor Attenuation in Head and Neck Cancers: A Prospective Study
Volume: 17
Author(s): Ugur Toprak, Suzan Saylisoy, Durmus Etiz, Emre Entok, Murat Tepe*, Melek Cosar Akcay and Murat Dincer
Affiliation:
- Department of Radiology, Private Umit Hospital, Eskisehir,Turkey
Keywords:
Attenuation, computed tomography, PET/CT, standard uptake value, neck, squamous cell cancer.
Abstract:
Objective: The study aimed to investigate the relationship between the ratio of lymph
node attenuation to primary lesion attenuation on contrast-enhanced CT and the PET/CT standard
uptake value (SUVmax) in head and neck squamous cell cancer (HNSCC).
Methods: Volunteers with advanced-stage, histopathologically proven HNSCC, indicated to have
radiotherapy/chemoradiotherapy, were evaluated for CT and PET/CT for radiotherapy planning.
The attenuation and SUVmax of the primary lesion and the largest, possibly metastatic lymph
node, and the round index and volume of the lymph node were calculated. The relationship between
lymph node/primary lesion attenuation and SUVmax ratios was investigated. The differences
in CT findings between the SUVmax < and ≥3 groups were examined.
Results: Thirty-two cases with adequate diagnostic quality were studied. There was a very strong
positive correlation between the primary lesion and lymph node attenuation (r=0.817, p<0.001), a
strong correlation between the lymph node volume and SUVmax (r=0.681, p<0.001), and a moderate
negative correlation between lymph node/primary lesion SUVmax and attenuation (r=-0.503,
p=0.004). In patients with ≥3 SUVmax, lymph node volume and lymph node/primary lesion SUVmax
were significantly higher, and the attenuation ratio was close to 1 (PPV 94.1, 86.3%, respectively).
Conclusion: In HNSCC, the lymph node/primary lesion attenuation ratio can be used instead of
SUVmax if supported by other conventional CT findings. Metastasis should be considered if
lymph node attenuation is similar to primary mass attenuation and excluded if higher. CT attenuation
rate can be used as a supportive finding if PET/CT cannot be performed or lymph node SUVmax
is close to the acceptable cut-off for metastasis.
