Role of dynamic contrast enhanced MR perfusion in differentiation between benign and malignant tumors

The Clinical Application of Dynamic Contrast-Enhanced MRI in Canine Masses of Mesenchymal and Epithelial Origin: A Preliminary Case Series

Evaluating masses of mesenchymal and epithelial origin accurately using computed tomography (CT) has several limitations in dogs. This study aimed to present dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to aid in improving the diagnostic accuracy for masses of mesenchymal and epithelial origin in veterinary medicine. Four dogs diagnosed with benign and malignant soft tissue sarcoma (STS), cholesteatoma, or squamous cell carcinoma underwent CT, conventional MRI, and DCE-MRI. Ktrans is a quantitative DCE-MRI parameter representing vascular permeability and tissue perfusion and is related to the potential for malignancy. Hemangiopericytomas (Grade II, STS) showed a higher Ktrans than normal muscle tissue and myxosarcoma (Grade I, STS). Squamous cell carcinoma (a malignant epithelial tumor) also showed a higher Ktrans than normal muscle tissue and cholesteatoma (a mass originating from keratinized squamous epithelium). These results suggest that higher Ktrans values may indicate a greater likelihood that a lesion is more malignant. In conclusion, Ktrans might be useful as a biomarker for evaluating the malignancy of a mass and as an indicator of lesion characteristics in dogs.

MRI features of sinonasal tract angiofibroma/juvenile nasopharyngeal angiofibroma: Case series and systematic review

BACKGROUND AND PURPOSE

To comprehensively summarize the radiological characteristics of sinonasal tract angiofibroma (STA) (commonly known as juvenile nasopharyngeal angiofibroma).

METHODS

Forty-four lesions from 41 cases provided by 33 study articles identified through a systematic review and 13 lesions from 13 cases from our institution associated with patients with STA who underwent MRI were included in the review study, carried out by two board-certified experienced radiologists.

RESULTS

The study participants were all male patients with a mean age of 15.6 years at the time of diagnosis. All of them presented with nasal cavity lesions (100%), predominantly in the nasopharynx (98.2%). The sphenopalatine foramen/pterygopalatine fossa was involved in 76.0%, and compressive shift of the posterolateral wall of the maxillary sinus was present in more than half (57.9%). T2-weighted imaging signal intensity was heterogeneous with mixed high and iso intensities as compared to skeletal muscle (100%). T1-weighted imaging showed partial high signal intensity in 61.1% of the cases. Flow void and intense enhancement were present in almost all cases. Cystic/nonenhancement changes on contrast-enhanced MRI were relatively common (40.8%). The mean apparent diffusion coefficient value (2.07 × 10-3  mm2 /second) and some quantitative dynamic contrast-enhanced MRI parameters were high. There was a significant difference in the frequency of residual/recurrent lesions based on the presence of MRI findings of skull base invasion (p = .017) and intracranial extension (p = .003).

CONCLUSIONS

We summarized the MRI findings of STA that can facilitate timely diagnosis and appropriate management.

Differentiation of Benign From Malignant Sinonasal Masses Using Diffusion Weighted Imaging and Dynamic Contrast Enhanced Magnetic Resonance Imaging

BACKGROUND

The sinonasal region is affected by a variety of neoplasms. A differentiation between benign and malignant masses is essential both for management and prognostication. Morphological analysis often does not allow this differentiation.

OBJECTIVES

This article aims to assess the value of advanced MRI (diffusion [DWI] and dynamic contrast enhanced MRI [DCE-MRI]) in differentiation of benign and malignant sinonasal masses.

METHODS

This prospective study included 40 patients with sinonasal masses who underwent advanced MR on 3T MR scanner. The lesions were analyzed based on morphological characteristics, qualitative, quantitative diffusion parameters, and time signal intensity curves. Apparent diffusion coefficient (ADC) values were acquired using b values of 50 and 1000 s/mm². The accuracy of DWI, DCE-MRI, and combined DWI/DCE-MRI in differentiating benign from malignant sinonasal masses were analyzed.

RESULTS

Perineural extension and growth pattern of the tumor were the best morphological discriminators. Mean ADC values for benign and malignant lesions were 1.675  ±  0.561 and 0.903  ±  0.405  × 10^-3 mm²/sec, ,respectively. ROC revealed that ADC cutoff value of 1.005  × 10^-3 mm²/sec provided an accuracy of 92.5% in differentiating benign from malignant masses (P value <.01). On excluding the benign vascular masses (Juvenile Nasopharyngeal Angiofibroma and hemangioma), the time signal intensity curve showed 78% accuracy (P value <.001). The highest diagnostic performance was achieved by combining DWI and DCE-MRI (95% accuracy).

CONCLUSION

DWI has higher accuracy than DCE-MRI. Quantitative DWI is preferable over qualitative DWI. Accuracy of DCE-MRI can be increased by excluding vascular masses with characteristic imaging features. DWI and DCE-MRI have the highest accuracy when used in combination than either of them alone in differentiating benign from malignant sinonasal masses.

Dynamic contrast-enhanced magnetic resonance imaging for differentiating head and neck paraganglioma and schwannoma

BACKGROUND AND PURPOSE

Morphological assessment with conventional magnetic resonance imaging (MRI) sequences has limited specificity to distinguish between paragangliomas and schwannomas. Assessing the differences in microvascular properties through pharmacokinetic parameters of dynamic contrast-enhanced (DCE)-MRI can provide additional information to aid in this differentiation.

MATERIALS AND METHODS

A prospective study on MR characterization of neck masses was performed between January 2017 and March 2019 in our department, out of which 40 patients with head and neck paragangliomas (HNPGLs) (33 lesions) and schwannomas (15 lesions) were included in this analysis. MR perfusion using dynamic axial T1WI fat suppressed fast spoiled gradient recalled sequence with parallel imaging was performed in all the patients, in addition to single-shot turbo spin-echo axial diffusion weighted imaging (DWI) and routine MRI. ROI-based method was used to obtain signal-time curves, permeability measurements, and mean apparent diffusion coefficient (ADC) to differentiate paragangliomas from schwannomas. Statistical analysis was done to assess the significance and establish a cutoff to distinguish between the two entities. The available images of DOTANOC PET/CT (34 lesions) were analyzed retrospectively. Correlations between the perfusion, diffusion, and molecular PET/CT parameters were done.

RESULTS

Paragangliomas had a higher wash-in rate, wash-out rate, K_trans, K_ep , and V_p (p < 0.001); while schwannomas had a higher relative enhancement (p < 0.012), time to peak, time of onset, brevity of enhancement, and V_e (p < 0.001). Among the perfusion parameters, K_ep (area under curve (AUC) 0.994) and V_p (AUC 0.992) were found to have the highest diagnostic value. In diffusion-weighted imaging, paragangliomas had a lower mean ADC compared to schwannomas (p < 0.001). The SUV_max and SUV_mean were significantly associated with K_trans , K_ep , and V_p in paragangliomas.

CONCLUSION

DCE-MRI in addition to DWI-MRI can accurately distinguish HNPGL from schwannoma and may replace the need for any additional imaging and preoperative biopsy in most cases.