Value of 2-[18F]-Fluoro-2-Deoxy-D-Glucose Imaging With Dual-Head Gamma Camera in Coincidence Mode

Value of diffusion MR imaging in differentiation of recurrent head and neck malignancies from post treatment changes

PURPOSE

Role of diffusion-weighted (DW) MR imaging in differentiating residual or recurrent neck malignancies from postoperative/post-radiation changes with histopathological correlation and comparison with PET-CT.

METHODS AND MATERIALS

Prospective observational study for a period of 1 year in 62 post-radiation/post-operative patients suspected to have residual/recurrent tumors of neck with lesion diameter more than 5 mm measured on MRI.

RESULTS

Mean ADC for recurrent/residual tumors: 1.008 ± 0.220 × 10^-3 mm²/s - significantly lower than mean ADC value for post-treatment changes of 1.69 ± 0.40 × 10^-3 mm²/s (p < 0.0001). The overall diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the qualitative assessment for the use of DWI in differentiating tumors recurrence from post-treatment changes were 96.6%, 96% and 83.3%, respectively. Upon quantitative analysis of the DW imaging data, a threshold ADC value of 1.3 × 10^-3 mm²/s used for differentiating between post-treatment changes and recurrent cancers showed the highest combined sensitivity of 94%, specificity of 83.3%, accuracy of 93.6%, positive predictive value of 95.9%, and negative predictive value of 83.3%.

CONCLUSION

DW MRI is a promising non-invasive MRI technique used to differentiate recurrent/residual head and neck malignancies from posttreatment changes based on ADC values. DWI offers advantage as it has a short scanning time and can be safely added to standard MRI protocol with minimum patient discomfort. Complementary use of DWI and PET/CT imaging may increase diagnostic confidence for differentiating recurrent disease from radiation therapy-induced changes after 6-12 months in posttreatment cases.

Detection of loco-regional recurrence in malignant head and neck tumors: a comparison of CT, MRI, and FDG PET-CT

BACKGROUND

The early and accurate detection of local or regional recurrence of head and neck tumor is critically important.

PURPOSE

To compare the diagnostic accuracy of contrast-enhanced computed tomography (CT), contrast-enhanced magnetic resonance imaging (MRI), and fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT, alone and in combination, in detecting the locoregional recurrence of malignant head and neck tumor.

MATERIAL AND METHODS

A total of 93 patients with loco-regional recurrence of malignant head and neck tumors underwent CT, MRI, and PET-CT within 30 days before surgery. CT, MRI, and PET-CT for each patient were retrospectively reviewed to determine the presence of recurrent tumors in the primary site on a patient-by-patient basis and that of regional lymph nodes on a level-by-level basis. The diagnostic accuracy of CT, MRI, and PET-CT, alone and combined, were accessed with the postoperative histopathological findings or with 12-month follow-up results as the standard of reference.

RESULTS

The sensitivity/specificity/and accuracy of CT, MRI, and PET-CT for the detection of primary site recurrence was 89.9/85.7/89.3%, 94.9/85.7/93.6%, and 97.5/92.9/96.8%, respectively. The sensitivity/specificity/accuracy of CT, MRI, and PET-CT for the detection of nodal recurrence was 66.3/99.4/92.4%, 74.7/99.4/94.2%, and 85.5/94.9/93.0%, respectively. MRI + PET-CT achieved the best performance in the receiver operating characteristics curve analysis (Az value = 0.958 for primary site recurrence and 0.929 for nodal recurrence).

CONCLUSION

MRI + PET-CT offered the highest diagnostic performance in the detection of loco-regional recurrence of malignant head and neck tumor, compared with CT, MRI, PET-CT, and other combinations including CT.

Accuracy of positron emission tomography in the evaluation of patients treated with chemoradiotherapy for mucosal head and neck cancer

BACKGROUND

The aim of this study was to evaluate the accuracy of positron emission tomography (PET) in assessing the patients treated with primary chemoradiotherapy for mucosal carcinoma of the head and neck.

METHODS

A retrospective review of patients with biopsy-proven cancer of mucosal head and neck sites receiving chemoradiotherapy with curative intent was undertaken.

RESULTS

Seventy-eight patients met the study criteria. Staging PET identified unsuspected distant metastatic disease in 11% of patients. Sixty-one patients (78%) had a complete metabolic response on PET, with 17 showing residual disease. Sensitivity of PET was 82% (positive predictive value: 82%) and specificity was 95% (negative predictive value: 95%). Accuracy of PET response was significantly better than clinical assessment and conventional imaging (p < .002, p < .001, respectively).

CONCLUSION

PET has been found to be significantly better than clinical examination or conventional imaging in restaging patients after chemoradiotherapy. Patients with a complete response on posttreatment PET have a significant survival advantage and can be safely observed.