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Temporal Evolution of Parotid Volume and Parotid Apparent Diffusion Coefficient in Nasopharyngeal Carcinoma Patients Treated by Intensity-Modulated Radiotherapy Investigated by Magnetic Resonance Imaging: A Pilot Study.

Juan CJ, Cheng CC, Chiu SC, Jen YM, Liu YJ, Chiu HC, Kao HW, Wang CW, Chung HW, Huang GS, Hsu HH - PLoS ONE (2015)

Bottom Line: A P value less than 0.05 was considered as statistically significant.The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3).The parotid ADC was positively associated with the radiation dose significantly (R(2) = 0.212; P = .0001) and was negatively associated with RMI significantly (R(2) = 0.203; P = .00096) significantly.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, National Defense Medical Center, Taipei, Taiwan, Republic of China; Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan, Republic of China.

ABSTRACT

Purpose: To concurrently quantify the radiation-induced changes and temporal evolutions of parotid volume and parotid apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma (NPC) patients treated by intensity-modulated radiotherapy by using magnetic resonance imaging (MRI).

Materials and methods: A total of 11 NPC patients (9 men and 2 women; 48.7 ± 11.7 years, 22 parotid glands) were enrolled. Radiation dose, parotid sparing volume, severity of xerostomia, and radiation-to-MR interval (RMI) was recorded. MRI studies were acquired four times, including one before and three after radiotherapy. The parotid volume and the parotid ADC were measured. Statistical analysis was performed using SPSS and MedCalc. Bonferroni correction was applied for multiple comparisons. A P value less than 0.05 was considered as statistically significant.

Results: The parotid volume was 26.2 ± 8.0 cm(3) before radiotherapy. The parotid ADC was 0.8 ± 0.15 × 10(-3) mm(2)/sec before radiotherapy. The parotid glands received a radiation dose of 28.7 ± 4.1 Gy and a PSV of 44.1 ± 12.6%. The parotid volume was significantly smaller at MR stage 1 and stage 2 as compared to pre-RT stage (P < .005). The volume reduction ratio was 31.2 ± 13.0%, 26.1 ± 13.5%, and 17.1 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3). The ADC increase ratio was 35.7 ± 17.4%, 27.0 ± 12.8%, and 20.2 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was negatively correlated to the parotid volume (R = -0.509; P < .001). The parotid ADC was positively associated with the radiation dose significantly (R(2) = 0.212; P = .0001) and was negatively associated with RMI significantly (R(2) = 0.203; P = .00096) significantly. Multiple regression analysis further showed that the post-RT parotid ADC was related to the radiation dose and RMI significantly (R(2) = 0.3580; P < .0001). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (R(2) = 0.473; P < .0001), while the parotid ADC was positively associated with the dry mouth grade significantly (R(2) = 0.288; P = .015).

Conclusion: Our pilot study successfully demonstrates the concurrent changes and temporal evolution of parotid volume and parotid ADC quantitatively in NPC patients treated by IMRT. Our results suggest that the reduction of parotid volume and increase of parotid ADC are dominated by the effect of acinar loss rather than edema at early to intermediate phases and the following recovery of parotid volume and ADC toward the baseline values might reflect the acinar regeneration of parotid glands.

No MeSH data available.


Related in: MedlinePlus

Parotid volume versus xerostomia (7A) and parotid ADC versus xerostomia (7B) in nasopharyngeal carcinoma patients treated by intensity-modulated radiotherapy.The parotid volume is significant lower in grades 1 and 2 as compared to grade 0 (P < .005). On the contrary, the parotid ADC was significant higher in grades 1 and 2 as compared to grade 0 (P < .005). Note: Grade 0 represents no symptom of dry mouth; grade 1 represents slight dryness of the mouth with good response on stimulation; grade 2 represents moderate dryness with poor response on stimulation.
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pone.0137073.g007: Parotid volume versus xerostomia (7A) and parotid ADC versus xerostomia (7B) in nasopharyngeal carcinoma patients treated by intensity-modulated radiotherapy.The parotid volume is significant lower in grades 1 and 2 as compared to grade 0 (P < .005). On the contrary, the parotid ADC was significant higher in grades 1 and 2 as compared to grade 0 (P < .005). Note: Grade 0 represents no symptom of dry mouth; grade 1 represents slight dryness of the mouth with good response on stimulation; grade 2 represents moderate dryness with poor response on stimulation.

Mentions: Parotid volume and parotid ADC in each dry mouth grade were graphically shown on Fig 7. The parotid volume was significantly smaller at grade 1 (P < .005) and grade 2 (P < .005) as compared to that at grade 0, respectively. The parotid volume at grade 1 did not differ from that at grade 2 (P = .187). The parotid ADC was significantly higher at grade 1 (P < .005) and grade 2 (P < .005) as compared to that at grade 0, respectively. The parotid ADC at grade 1 did not differ from that at grade 2 (P = 1). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (y = 29.201–8.326x ml; R2 = 0.473; P < .0001). On the contrary, the parotid ADC was positively associated with dry mouth grade significantly (y = 0.828 + 0.138x ×10-3mm/sec2; R2 = 0.288; P = .015).


Temporal Evolution of Parotid Volume and Parotid Apparent Diffusion Coefficient in Nasopharyngeal Carcinoma Patients Treated by Intensity-Modulated Radiotherapy Investigated by Magnetic Resonance Imaging: A Pilot Study.

Juan CJ, Cheng CC, Chiu SC, Jen YM, Liu YJ, Chiu HC, Kao HW, Wang CW, Chung HW, Huang GS, Hsu HH - PLoS ONE (2015)

Parotid volume versus xerostomia (7A) and parotid ADC versus xerostomia (7B) in nasopharyngeal carcinoma patients treated by intensity-modulated radiotherapy.The parotid volume is significant lower in grades 1 and 2 as compared to grade 0 (P < .005). On the contrary, the parotid ADC was significant higher in grades 1 and 2 as compared to grade 0 (P < .005). Note: Grade 0 represents no symptom of dry mouth; grade 1 represents slight dryness of the mouth with good response on stimulation; grade 2 represents moderate dryness with poor response on stimulation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556378&req=5

pone.0137073.g007: Parotid volume versus xerostomia (7A) and parotid ADC versus xerostomia (7B) in nasopharyngeal carcinoma patients treated by intensity-modulated radiotherapy.The parotid volume is significant lower in grades 1 and 2 as compared to grade 0 (P < .005). On the contrary, the parotid ADC was significant higher in grades 1 and 2 as compared to grade 0 (P < .005). Note: Grade 0 represents no symptom of dry mouth; grade 1 represents slight dryness of the mouth with good response on stimulation; grade 2 represents moderate dryness with poor response on stimulation.
Mentions: Parotid volume and parotid ADC in each dry mouth grade were graphically shown on Fig 7. The parotid volume was significantly smaller at grade 1 (P < .005) and grade 2 (P < .005) as compared to that at grade 0, respectively. The parotid volume at grade 1 did not differ from that at grade 2 (P = .187). The parotid ADC was significantly higher at grade 1 (P < .005) and grade 2 (P < .005) as compared to that at grade 0, respectively. The parotid ADC at grade 1 did not differ from that at grade 2 (P = 1). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (y = 29.201–8.326x ml; R2 = 0.473; P < .0001). On the contrary, the parotid ADC was positively associated with dry mouth grade significantly (y = 0.828 + 0.138x ×10-3mm/sec2; R2 = 0.288; P = .015).

Bottom Line: A P value less than 0.05 was considered as statistically significant.The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3).The parotid ADC was positively associated with the radiation dose significantly (R(2) = 0.212; P = .0001) and was negatively associated with RMI significantly (R(2) = 0.203; P = .00096) significantly.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, National Defense Medical Center, Taipei, Taiwan, Republic of China; Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan, Republic of China.

ABSTRACT

Purpose: To concurrently quantify the radiation-induced changes and temporal evolutions of parotid volume and parotid apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma (NPC) patients treated by intensity-modulated radiotherapy by using magnetic resonance imaging (MRI).

Materials and methods: A total of 11 NPC patients (9 men and 2 women; 48.7 ± 11.7 years, 22 parotid glands) were enrolled. Radiation dose, parotid sparing volume, severity of xerostomia, and radiation-to-MR interval (RMI) was recorded. MRI studies were acquired four times, including one before and three after radiotherapy. The parotid volume and the parotid ADC were measured. Statistical analysis was performed using SPSS and MedCalc. Bonferroni correction was applied for multiple comparisons. A P value less than 0.05 was considered as statistically significant.

Results: The parotid volume was 26.2 ± 8.0 cm(3) before radiotherapy. The parotid ADC was 0.8 ± 0.15 × 10(-3) mm(2)/sec before radiotherapy. The parotid glands received a radiation dose of 28.7 ± 4.1 Gy and a PSV of 44.1 ± 12.6%. The parotid volume was significantly smaller at MR stage 1 and stage 2 as compared to pre-RT stage (P < .005). The volume reduction ratio was 31.2 ± 13.0%, 26.1 ± 13.5%, and 17.1 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3). The ADC increase ratio was 35.7 ± 17.4%, 27.0 ± 12.8%, and 20.2 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was negatively correlated to the parotid volume (R = -0.509; P < .001). The parotid ADC was positively associated with the radiation dose significantly (R(2) = 0.212; P = .0001) and was negatively associated with RMI significantly (R(2) = 0.203; P = .00096) significantly. Multiple regression analysis further showed that the post-RT parotid ADC was related to the radiation dose and RMI significantly (R(2) = 0.3580; P < .0001). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (R(2) = 0.473; P < .0001), while the parotid ADC was positively associated with the dry mouth grade significantly (R(2) = 0.288; P = .015).

Conclusion: Our pilot study successfully demonstrates the concurrent changes and temporal evolution of parotid volume and parotid ADC quantitatively in NPC patients treated by IMRT. Our results suggest that the reduction of parotid volume and increase of parotid ADC are dominated by the effect of acinar loss rather than edema at early to intermediate phases and the following recovery of parotid volume and ADC toward the baseline values might reflect the acinar regeneration of parotid glands.

No MeSH data available.


Related in: MedlinePlus