Improved Cervical Lymph Node Characterization among Patients with Head and Neck Squamous Cell Carcinoma Using MR Texture Analysis Compared to Traditional FDG-PET/MR Features Alone

Accurate differentiation of benign and malignant cervical lymph nodes is important for prognosis and treatment planning in patients with head and neck squamous cell carcinoma. We evaluated the diagnostic performance of magnetic resonance image (MRI) texture analysis and traditional 18F-deoxyglucose positron emission tomography (FDG-PET) features. This retrospective study included 21 patients with head and neck squamous cell carcinoma. We used texture analysis of MRI and FDG-PET features to evaluate 109 histologically confirmed cervical lymph nodes (41 metastatic, 68 benign). Predictive models were evaluated using area under the curve (AUC). Significant differences were observed between benign and malignant cervical lymph nodes for 36 of 41 texture features (p < 0.05). A combination of 22 MRI texture features discriminated benign and malignant nodal disease with AUC, sensitivity, and specificity of 0.952, 92.7%, and 86.7%, which was comparable to maximum short-axis diameter, lymph node morphology, and maximum standard uptake value (SUVmax). The addition of MRI texture features to traditional FDG-PET features differentiated these groups with the greatest AUC, sensitivity, and specificity (0.989, 97.5%, and 94.1%). The addition of the MRI texture feature to lymph node morphology improved nodal assessment specificity from 70.6% to 88.2% among FDG-PET indeterminate lymph nodes. Texture features are useful for differentiating benign and malignant cervical lymph nodes in patients with head and neck squamous cell carcinoma. Lymph node morphology and SUVmax remain accurate tools. Specificity is improved by the addition of MRI texture features among FDG-PET indeterminate lymph nodes. This approach is useful for differentiating benign and malignant cervical lymph nodes.

Value of whole-body MRI for the assessment of response to albendazole in disseminated neurocysticercosis: a prospective follow-up study

BACKGROUND

Disseminated neurocysticercosis is defined as simultaneous involvement of the brain (≥3 cysts) and at least one additional body site/organ. We aimed to identify disseminated cystic lesions in other body parts and investigate the effect of albendazole.

METHODS

We enrolled patients with multiple (≥3) neurocysticercosis brain lesions. Whole-body MRI (short tau inversion recovery coronal sequences) was performed to assess the number of lesions in the brain and other body parts at baseline and 3 months after albendazole therapy.

RESULTS

We screened 35 patients with multiple brain neurocysticercosis. In 13 patients, whole-body MRI demonstrated disseminated neurocysticercosis lesions. Ten patients were treated with albendazole. We excluded three patients. Brain MRI showed a mean lesion count of 163.6±193.8. Whole-body MRI (excluding the brain) showed a mean lesion count of 629.9±486.1. After albendazole therapy, the lesion load of the brain reduced significantly (163.6±193.8 to 99±178.3; p=0.008). Similarly, whole-body MRI showed a significant reduction in extracerebral neurocysticercosis lesion load (629.9±486.1 to 183.4±301.9; p=0.005). Three patients had complete resolution, five patients showed ≥50% reduction and two patients had <50% reduction in extracerebral lesion load.

CONCLUSION

Whole-body MRI should routinely be performed in multiple neurocysticercosis lesions of the brain. Albendazole treatment leads to a remarkable reduction in neurocysticercosis lesions throughout the body.

The value of magnetic resonance imaging in target volume delineation of base of tongue tumours--a study using flexible surface coils

INTRODUCTION

Magnetic resonance imaging (MRI) provides superior diagnostic accuracy over computed tomography (CT) in oropharyngeal tumours. Precise delineation of the gross tumour volume (GTV) is mandatory in radiotherapy planning when a GTV boost is required. CT volume definition in this regard is poor. We studied the feasibility of using flexible surface (flex-L) coils to obtain MR images for MR-CT fusion to assess the benefit of MRI over CT alone in planning base of tongue tumours.

METHODS

Eight patients underwent CT and MRI radiotherapy planning scans with an immobilisation device. Distortion-corrected T1-weighted post-contrast MR scans were fused to contrast-enhanced planning CT scans. GTV, clinical target and planning target volumes (CTV, PTV) and organs at risk (OAR) were delineated on CT, then on MRI with blinding to the CT images. The volumetric and spatial differences between MRI and CT volumes for GTV, CTV, PTV and OAR were compared. MR image distortions due to field inhomogeneity and non-linear gradients were corrected and the need for such correction was evaluated.

RESULTS

The mean primary GTV was larger on MRI (22.2 vs. 9.5 cm(3), p=0.05) than CT. The mean primary and nodal GTV (i.e. BOT and macroscopic nodes) was significantly larger on MRI (27.2 vs. 14.4 cm(3), p=0.05). The volume overlap index (VOI) between MRI and CT for the primary was 0.34 suggesting that MRI depicts parts of the primary tumour not detected by CT. There was no significant difference in volume delineation between MR and CT for CTV, PTV, nodal CTV and nodal PTV. MRI volumes for brainstem and spinal cord were significantly smaller due to improved organ definition (p=0.002). Susceptibility and gradient-related distortions were not found to be clinically significant.

CONCLUSION

MRI improves the definition of tongue base tumours and neurological structures. The use of MRI is recommended for GTV dose-escalation techniques to provide precise depiction of GTV and improved sparing of spinal cord and brainstem.