Histogram analysis of dynamic contrast-enhanced magnetic resonance imaging in the differential diagnosis of parotid tumors

Semiquantitative magnetic resonance imaging parameters for differentiating parotid pleomorphic adenoma from Warthin tumor

Background

Accurately distinguishing between pleomorphic adenoma (PA) and Warthin tumor (WT) is beneficial for their respective management. Preoperative magnetic resonance imaging (MRI) can provide valuable information due to its excellent soft tissue contrast. This study explored the value of semiquantitative contrast-enhanced MRI parameters in the differential diagnosis of PA and WT.

Methods

Data from 106 patients, 62 with PA and 44 with WT (confirmed by histopathology) were retrospectively and consecutively analyzed. The tumor-to-spinal cord contrast ratios (TSc-CR) based on the mean, maximum, and minimum signal intensity (T1-mean TSc-CR, T1-max TSc-CR, and T1-min TSc-CR, respectively) in the early and delayed phases were calculated on contrast-enhanced T1-weighted images as semiquantitative parameters, and then compared between PA and WT. Receiver operating characteristic (ROC) curve analysis and areas under the curve (AUCs) were used to determine the performance of these parameters in the differential diagnosis of PA from WT.

Results

Except T1-min TSc-CR in the early phase, all semiquantitative MRI parameters differed significantly between PA and WT (all P<0.05). T1-max TSc-CR showed higher sensitivity {70.45% [95% confidence interval (CI): 0.548-0.832]} and specificity [70.97% (95% CI: 0.581-0.818)] and had a higher AUC [0.707 (95% CI: 0.610-0.791)] in the early phase when using a cutoff value of 1.89. T1-max TSc-CR showed higher sensitivity [88.64% (95% CI: 0.754-0.962)], specificity [72.58% (95% CI: 0.598-0.831)], and AUC [0.854 (95% CI: 0.772-0.915)] in the delayed phase when using a cutoff value of 2.33. The sensitivity, specificity, and AUC were improved to 90.91% (95% CI: 0.783-0.975), 93.55% (95% CI: 0.843-0.982), and 0.960 (95% CI: 0.903-0.988), respectively, after combination of all semiquantitative parameters in the early and delayed phases. The two radiologists had excellent interobserver agreement on TSc-CRs [all interclass correlation coefficient (ICC) >0.75].

Conclusions

Semiquantitative parameters using TSc-CR are valuable in distinguishing PA from WT, and a combination of these parameters can improve the differential diagnostic efficiency.

Advantages of contrast-enhanced CT combined with DCE-MRI in identifying malignant parotid tumor

OBJECTIVE

To study the value of single and combined application of contrast-enhanced computerized tomography (CT) and dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in diagnosing parotid tumors.

METHODS

In this retrospective study, 82 patients with parotid gland mass who received contrast-enhanced CT and DCE-MRI detection in The First People's Hospital of Huzhou from March 2018 to March 2022 were selected as study subjects. The nature of the parotid tumor was pathologically examined following the surgery. According to the pathological diagnosis results, these patients were divided into a benign group (n=59) and a malignant group (n=23). All patients underwent contrast-enhanced CT and DCE-MRI examinations. The diagnostic accuracy rates of contrast-enhanced CT, DCE-MRI and the joint application were compared. The CT or MRI images of benign and malignant parotid tumors were compared. The correlation of parotid cancer with the imaging features was analyzed. Diagnostic efficiency of contrast-enhanced CT, DCE-MRI and joint application for parotid cancer was assessed by receiver operating characteristic curve.

RESULTS

In terms of diagnostic accuracy, there was a significant difference between contrast-enhanced CT combined with DCE-MRI and contrast-enhanced CT alone (95.12% vs. 81.71%, P<0.001), and between the joint application and DCE-MRI alone (95.12% vs. 86.58%, P=0.004). Results of contrast-enhanced CT revealed statistical differences in tumor boundary, tumor size, calcification and cystic degeneration between benign and malignant tumors (P<0.05), but no obvious difference in lymph node enlargement between the two groups. MRI results showed that there were differences in the DCE-MRI time-signal intensity curve and ADC value between benign and malignant tumors (P<0.05). Correlation analysis results showed that the malignant tumor was negatively correlated with tumor boundary, calcification, cystic degeneration and ADC values, and it was positively correlated with DCE-MRI time-signal intensity curve and tumor size (P<0.05). Analysis of diagnostic efficacy showed that contrast-enhanced CT combined with DCE-MRI were significantly better than contrast-enhanced CT alone in terms of sensitivity and specificity (P<0.05). Moreover, the sensitivity of the joint application was also higher than that of MRI alone, while no obvious difference was found for specificity between joint application and MRI alone. The areas under the curve of contrast-enhanced CT combined with DCE-MRI in diagnosing malignant parotid tumor was remarkably greater than that of CT or MRI alone (P<0.05).

CONCLUSION

Contrast-enhanced CT combined with DCE-MRI can significantly improve the diagnostic accuracy, sensitivity and specificity for malignant parotid tumor, and the joint application was able to point out the direction of targeted surgical treatment plans.

Parotid metastases from primary lung cancer: Case series and systematic review of the features

Most parotid metastases have been reported to come from the head and neck; however, cases metastasized from the lung are extremely rare. Missed diagnoses and misdiagnoses occurred quite a few times. Thus, accurately identifying the clinical features of parotid metastasis of lung cancer is important. However, current studies about this issue are mostly case reports, and little is known about the detailed and systematic aspects. We reported three cases of parotid metastases from lung cancer and then systematically searched similar cases through “Pub-Med” and “Web of Science”. Finally, twenty-three patients were included in the study. Eighty-three percent of which were males, and 19 patients were over 50 years old. In all cases with smoking history mentioned, 93% were smokers. The predominant pathological type was small cell lung cancer (SCLC, 13 patients, 56%). Seventeen combined with other site metastasis, while more than half of which were brain metastases. The survival time ranged from 3months-17years, and as for SCLCs, it was only 3months-40months. It can be concluded that clinical features, such as sex, age, smoking history, pathological types, and metastasis patterns, could provide valuable evidence for diagnosis. The lung seems to be the most common primary site of parotid metastases except for head and neck tumors. The two circumstances, SCLC coexisting with Warthin’s tumor and parotid small cell carcinoma with lung metastasis, should be differentiated from parotid metastasis of lung cancer with caution For cases presented as SCLC, more aggressive strategies, such as chemotherapy with immunotherapy and maintenance therapy, may be more suitable. Due to the greater tendency of brain metastasis in such diseases, whole-brain radiation therapy, stereotactic radiosurgery or prophylactic cranial irradiation should be applied to corresponding patients in time. Additionally, lung cancer parotid metastases may be a marker of poor prognosis.