Minor salivary gland tumors in the oral cavity: Diagnostic value of dynamic contrast-enhanced MRI

Adenoid cystic carcinoma of head and neck: Summary and review of imaging findings

Purpose

Current reports of adenoid cystic carcinoma of the head and neck (ACC) are all case reports, and there is no basilar summary of its imaging findings. This study aims to summarise ACC's computed tomography (CT) and magnetic resonance imaging (MRI) findings to improve radiologists' knowledge of this disease.

Methods

We collected clinical and imaging data of patients with ACC during the last decade, and two radiologists retrospectively analysed the imaging characteristics.

Results

Of the 16 patients included, six were able to self-perceive bulkiness, and 11 had regional pain. Tumour morphology was regular in six cases, with clear borders in 11 cases, invasion of the surrounding bony mass in 12 cases, and invasion of peripheral nerves in 15 cases. CT mostly shows an irregular soft-tissue density mass with mild-to-moderate enhancement after contrast medium administration. On MRI, the ACC showed isointense or hypointense signals on T1-weighted images (T1WI) and hyperintense or slightly hyperintense signals on T2-weighted images (T2WI). All signals were markedly enhanced after gadolinium enhancement.

Conclusions

ACC often has an irregular morphology, sometimes with a cystic component, enhancement on enhancement scans, easy destruction of adjacent bone, and invasion of peripheral nerves. The diagnosis should be considered when these features are encountered in clinical practice.

Proton Beam Therapy as a Curative Treatment for a Young Case of Unresectable Tracheal Adenoid Cystic Carcinoma

Primary tracheal adenoid cystic carcinoma (TACC) is a rare malignancy without an established treatment. Central airway obstruction due to TACC often decreases the quality of life and has life-threatening consequences. A 19-year-old man with unresectable TACC and central airway obstruction suffered from progressive cough and dyspnea after exercise. Proton beam therapy (PBT) was selected as the preferred treatment over systemic anti-cancer chemotherapy for TACC. PBT led to complete remission of TACC and the almost complete disappearance of the respiratory symptoms without adverse events. PBT is a useful and safe treatment for unresectable primary TACC.

Recent Advances, Systemic Therapy, and Molecular Targets in Adenoid Cystic Carcinoma of the Head and Neck

With an incidence of 3-4.5 cases per million, adenoid cystic carcinoma (ACC) of the head and neck is one of the most common tumors of the parotid and sublingual salivary glands. In the clinical course, ACC is shown to have an aggressive long-term behavior, which leads to the fact that radical surgical resection of the tumor with tumor-free margins remains the "gold standard" in treating ACC. Particle radiation therapy and systemic molecular biological approaches offer new treatment options. However, risk factors for the formation and prognosis of ACC have not yet been clearly identified. The aim of the present review was to investigate long-term experience of diagnosis and treatment as well as risk and prognostic factors for occurrence and outcome of ACC.

Adenoid cystic carcinoma of the parotid gland

Adenoid cystic carcinoma (ACC) is a slowly progressing malignant tumor of the salivary glands that mostly affects minor salivary glands. ACC of parotid gland is exceptionally rare. In this article, we aimed to provide a case report of parotid gland ACC in a 55-year-old female that was misdiagnosed as benign mixed tumor. The patient was successfully treated by surgery without any complications. We recommend that ACC of parotid gland should be considered in differential diagnosis of benign mixed tumor since there still existed overlapped imaging characteristics.

Unusual presentation of parotid gland adenoid cystic carcinoma : A case presentation and literature review

Adenoid cystic carcinoma (ACC) represents approximately 10% of all epithelial salivary neoplasms and most commonly involves the parotid gland. We report CT and MRI finding of a 38-year-old young man presented to our ENT department with 02 years history of an external auditory canal stenosis. Physical examination revealed bilateral parotid gland swelling with a complete stenosis of the left external auditory canal. Temporal bone contrast enhanced CT-SCAN revealed is an isodense enhancing mass measuring 4 cm involving posterior and inferior external auditory canal wall, and invading the superficial lobe of the homolateral parotid gland. No bone erosion was noted. MRI investigation has shown a tumor process highly suspicious of malignancy centered on the left EAC involving the superficial lobe of the homolateral parotid gland. Adenoid cystic carcinoma (ACC) of the parotid gland was the final diagnosis, after surgical biopsy and histopathological examination. The Pre-operative check-up demonstrated multiple round shape lung lesions suggestive of multiple metastases. Considering the metastatic stage of the tumor, a collegial decision to adopt a palliative treatment approach based on chemotherapy was taken by the multidisciplinary oncology board.

Techniques, Tricks, and Stratagems of Oral Cavity Computed Tomography and Magnetic Resonance Imaging

The oral cavity constitutes a complex anatomical area that can be affected by many developmental, inflammatory, and tumoural diseases. MultiSlice Computed Tomography (MSCT) and Magnetic Resonance Imaging (MRI) currently represent the essential and complementary imaging techniques for detecting oral cavity abnormalities. Advanced MRI with diffusion-weighted imaging (DWI) and dynamic contrast-enhanced perfusion-weighted imaging (DCE-PWI) has recently increased the ability to characterise oral lesions and distinguish disease recurrences from post therapy changes. The analysis of the oral cavity area via imaging techniques is also complicated both by mutual close appositions of different mucosal surfaces and metal artifacts from dental materials. Nevertheless, an exact identification of oral lesions is made possible thanks to dynamic manoeuvres and specific stratagems applicable on MSCT and MRI acquisitions. This study summarises the currently available imaging techniques for oral diseases, with particular attention to the role of DWI, DCE-PWI, and dynamic manoeuvres. We also propose MSCT and MRI acquisition protocols for an accurate study of the oral cavity area.

Susceptibility artifacts induced by crowns of different materials with prepared teeth and titanium implants in magnetic resonance imaging

This study aimed to investigate the artifacts induced by crowns composed of different materials with prepared teeth and titanium implants. Resin, metal-ceramic, ceramic and zirconia crowns were fabricated and placed onto the prepared teeth on a human cadaver head or titanium implants with prosthesis abutments on a dry human mandible. The samples were scanned on a 1.5 T MRI apparatus, and artifact areas were defined as the signal intensity and signal loss adjacent to the prosthesis and measured by a threshold tool with ImageJ2x. Data were analyzed using SPSS 22.0. Resin, ceramic, zirconia, and precious metal-ceramic crowns barely produced artifacts on the cadaver skull (p > 0.999). By contrast, pure Ti and nonprecious metal-ceramic crowns created significant artifacts (p < 0.001). The average artifacts reduction of double Au-Pt and Ag-Pd metal-ceramic crowns combined with titanium implants and abutments was 79.49 mm² (p < 0.001) and 74.17 mm² (p < 0.001) respectively, while artifact areas were increased in double Co-Cr and Ni–Cr metal-ceramic crowns by 150.10 mm² (p < 0.001) and 175.50 mm² (p < 0.001) respectively. Zirconia, ceramic and precious metal-ceramic crowns induce less MRI artifacts after tooth preparation while precious metal-ceramic crowns alleviate artifacts in combination with titanium implants.

A Review of Salivary Gland Malignancies: Common Histologic Types, Anatomic Considerations, and Imaging Strategies

Major and minor salivary gland malignancies come in various shapes and sizes. They can present as palpable masses or can be detected incidentally when imaging patients for other indications. A complete evaluation of salivary gland malignancies requires knowledge of the anatomy and various routes of spread of neoplasias. Computed tomography (CT) and MR imaging are complementary tools in this respect and offer useful information to the proceduralist. Advanced imaging (diffusion-weighted imaging and PET-CT) and other modalities (eg, ultrasound) help with characterization, although biopsy or excision is often needed for definitive tissue diagnosis.

The diagnostic value of combining conventional, diffusion-weighted imaging and dynamic contrast-enhanced MRI for salivary gland tumors

OBJECTIVE

To determine the diagnostic value of combining conventional MRI, diffusion-weighted imaging (DWI) and dynamic contrast enhanced MRI (DCE-MRI) in salivary gland tumors.

METHODS

45 patients with salivary gland tumors were evaluated with conventional MRI, DWI and DCE-MRI prior to surgery and confirmed by pathologic findings. The apparent diffusion coefficient (ADC) was calculated from DWI that was obtained with a factor of 0 and 1000 s mm^-2. A time-intensity curve (TIC) was obtained from DCE-MRI.

RESULTS

In conventional MRI, benign tumors often showed well-defined and clear margins, malignant tumors showed irregular margins or infiltration into the surrounding tissue. There were significant differences with regard to the ADC values between pleomorphic adenoma (1.72 ± 0.29 × 10^-3 mm² s^-1) and malignant tumors (0.95 ± 0.09 × 10^-3 mm² s^-1, p < 0.05) and between adenolymphoma (0.74 ± 0.05 × 10^-3 mm² s^-1) and malignant tumors (p < 0.05). However, there was no significant differences in term of the ADC values between benign tumors (1.33 ± 0.52×10^-3 mm² s^-1) and malignant tumors. DCE-MRI showed benign tumors with A-type, B-type and D-type of TICs, and the malignant tumors with C-type TICs. A combination of all of these parameters yielded sensitivity, specificity, accuracy, and positive and negative predictive values of 90%, 97%, 95%, 90 and 97%, respectively.

CONCLUSION

An evaluation combining MRI morphologic findings and functional MRI (ADCs and TIC) appears to be useful in differentiating benign from malignant tumors in salivary gland tumors. Advances in knowledge: The study firstly dealt with the combination of conventional MRI, DWI-MRI with DCE-MRI in salivary gland tumors.

Dynamic Contrast-enhanced Magnetic Resonance Imaging for Differentiating Between Primary Tumor, Metastatic Node and Normal Tissue in Head and Neck Cancer

OBJECTIVE

To study the difference of the Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) parameters among the primary tumor, metastatic node and peripheral normal tissue of head and neck cancer.

MATERIALS AND METHODS

Consecutive newly-diagnosed head and neck cancer patients with nodal metastasis between December 2010 and July 2013 were recruited, and 25 patients (8 females; 24~63,mean 43±11 years old) were enrolled. DCE-MRI was performed in the primary tumor region including the regional lymph nodes on a 3.0-T MRI system. Three quantitative parameters: Ktrans (volume transfer constant), ve (volume fraction of extravascular extracellular space) and kep (the rate constant of contrast transfer) were calculated for the largest node. A repeated-measure ANOVA with a Greenhouse-Geisser correction and post hoc tests using the Bonferroni correction were used to evaluate the differences in Ktrans, ve and kep among primary tumors, metastatic nodes and normal tissue.

RESULTS

The values of both Ktrans and ve of normal tissue differed significantly from those of nodes (both P < 0.001) and primary tumors (both P < 0.001) respectively, while no significant differences of Ktrans and ve were observed between nodes and primary tumors (P = 0.075 and 0.365 respectively). The kep values of primary tumors were significantly different from those of nodes (P = 0.001) and normal tissue (P = 0.002), while no significant differences between nodes and normal tissue (P > 0.999).

CONCLUSION

The DCE-MRI parameters were different in the tumors, metastatic nodes and normal tissue in head and neck cancer. These findings may be useful in the characterization of head and neck cancer.

The value of combining conventional, diffusion-weighted and dynamic contrast-enhanced MR imaging for the diagnosis of parotid gland tumours

OBJECTIVES

The aim of this study was to determine the value of combining conventional MRI, diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE)-MRI in diagnosing solid neoplasms in the parotid gland.

METHODS

A total of 148 subjects (101 subjects with benign and 47 subjects with malignant tumours) were evaluated with conventional MRI, DWI and DCE-MRI prior to surgery and pathologic verification. The items observed with conventional MRI included the shape, capsule and signal intensity of parotid masses. The apparent diffusion coefficient (ADC) was calculated from DWI that was obtained with a b-factor of 0 and 1000 s mm^-2. A time-intensity curve (TIC) was obtained from DCE-MRI.

RESULTS

There were significant differences (p < 0.01) in the shape, capsule, ADC and TIC between benign and malignant parotid tumours. Irregular neoplasms without a capsule, ADC <1.12 × 10^-3 mm² s^-1 and a plateau enhancement pattern were valuable parameters for predicting malignant neoplasms. A combination of all of these parameters yielded sensitivity, specificity, accuracy, positive-predictive value and negative-predictive value of 85.1%, 94.1%, 91.2%, 87.0% and 93.1%, respectively.

CONCLUSIONS

A combined analysis using conventional MRI, DWI and DCE-MRI is helpful in distinguishing benign from malignant tumours in the parotid gland.

Value of Dynamic Contrast-Enhanced MRI to Detect Local Tumor Recurrence in Primary Head and Neck Cancer Patients

Treatment failures in head and neck cancer patients are mainly related to locoregional tumor recurrence. The objective of the present study was to evaluate the diagnostic accuracy of model-free dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to detect local recurrence during the surveillance of head and neck cancer patients.Our retrospective study enrolled 24 patients with primary head and neck cancer who had undergone definitive treatment. Patients were grouped into local recurrence (n = 12) or posttreatment change (n = 12) groups according to the results of biopsy or clinicoradiologic follow-up. The types of time-signal intensity (TSI) curves were classified as follows: "progressive increment" as type I, "plateau" as type II, and "washout" as type III. TSI curve types and their parameters (i.e., wash-in, Emax, Tmax, area under the curve [AUC]60, AUC90, and AUC120) were compared between the 2 study groups.The distributions of TSI curve types for local recurrence versus posttreatment change were statistically significant (P < 0.001) (i.e., 0% vs 83.3% for type I, 58.3% vs 16.7% for type II, and 41.7% vs 0% for type III). There were statistically significant differences in Emax, Tmax, and all of the AUC parameters between 2 groups (P < 0.0083 [0.05/6]). Receiver operating characteristic (ROC) curve analyses indicated that the TSI curve type was the best predictor of local recurrence with a sensitivity of 100% (95% CI, 73.5-100.0) and a specificity of 83.3% (95% CI, 51.6-97.9) (cutoff with type II).Model-free DCE-MRI using TSI curves and TSI curve-derived parameters detects local recurrence in head and neck cancer patients with a high diagnostic accuracy.

Dynamic contrast-enhanced MR in the diagnosis of lympho-associated benign and malignant lesions in the parotid gland

OBJECTIVE

The aim of this study was to determine if dynamic contrast-enhanced (DCE)-MRI can differentiate mucosa-associated lymphoid tissue (MALT) lymphoma from benign lymphoepithelial lesion (BLEL) in the parotid gland.

METHODS

25 patients with tumour-like BLEL and 20 patients with MALT lymphoma in the parotid gland confirmed by pathology were examined pre-operatively using routine MR series and DCE-MRI with a 1.5-T MR unit. The time to peak (TTP), time to start (TTS), SIstart, SImax and SIending were measured and the initial slope of increase (ISI) and relative washout ratio (RWO) were calculated separately from the time-intensity curve (TIC), and the types of TIC were analysed.

RESULTS

There were significant differences in the TTP and ISI between the two lesions (p < 0.001). The sensitivity, specificity and accuracy of TTP were all more than 90%. TICs were divided into three types according to the threshold of TTP and ISI: tumour-like BLEL: gradual type (Type II) and late increase type (Type III); MALT lymphoma: rapid increase and gradual type (Type I).

CONCLUSIONS

DCE-MRI contributed greatly to the differential diagnosis between tumour-like BLEL and MALT lymphoma in the parotid gland.

Dynamic Contrast-Enhanced MR Imaging in Head and Neck Cancer: Techniques and Clinical Applications

In the past decade, dynamic contrast-enhanced MR imaging has had an increasing role in assessing the microvascular characteristics of various tumors, including head and neck cancer. Dynamic contrast-enhanced MR imaging allows noninvasive assessment of permeability and blood flow, both important features of tumor hypoxia, which is a marker for treatment resistance for head and neck cancer. Dynamic contrast-enhanced MR imaging has the potential to identify early locoregional recurrence, differentiate metastatic lymph nodes from normal nodes, and predict tumor response to treatment and treatment monitoring in patients with head and neck cancer. Quantitative analysis is in its early stage and standardization and refinement of technique are essential. In this article, we review the techniques of dynamic contrast-enhanced MR imaging data acquisition, analytic methods, current limitations, and clinical applications in head and neck cancer.

Adenoid cystic carcinoma of the head and neck--An update

This article provides an update on the current understanding of adenoid cystic carcinoma of the head and neck, including a review of its epidemiology, clinical behavior, pathology, molecular biology, diagnostic workup, treatment and prognosis. Adenoid cystic carcinoma is an uncommon salivary gland tumor that may arise in a wide variety of anatomical sites in the head and neck, often with an advanced stage at diagnosis. The clinical course is characterized by very late recurrences; consequently, clinical follow-up should extend at least >15 years. The optimal treatment is generally considered to be surgery with postoperative radiotherapy to optimize local disease control. Much effort has been invested into understanding the tumor's molecular biological processes, aiming to identify patients at high risk of recurrence, in hopes that they could benefit from other, still unproven treatment modalities such as chemotherapy or biological therapy.

The application of dynamic contrast-enhanced MRI and diffusion-weighted MRI in patients with maxillofacial tumors

RATIONALE AND OBJECTIVES

To elucidate the characteristics of four types of tumors, including squamous cell carcinoma (SCC), malignant lymphoma (ML), malignant salivary gland tumors (MSGTs), and pleomorphic adenoma (Pleo), in the maxillofacial region using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI）data.

MATERIALS AND METHODS

A total of 59 tumors were included in this research. DCE-MRI and DW-MRI were performed. We applied the Tofts and Kermode model (TK model) for the DCE-MRI data and obtained three dependent parameters: the influx forward volume transfer constant into the extravascular extracellular space from the plasma (K(trans)), the fractional volume of extravascular extracellular space per unit volume of tissue (ve), and the fractional volume of plasma (vp).

RESULTS

Among the K(trans) values, there were no significant differences between the three types of malignant tumors; however, there was a significant difference between the SCC and Pleo (P = .0099). The ve values of the Pleo were highest, with significant differences compared to the other categories (SCC, P = .0012; ML, P = .0017; and MSGT, P = .041). The ML had the lowest ve values, and there were significant differences between ML and the other two types of malignant tumors (SCC, P = .0278 and MSGT, P = .0062). In 14 (24%) cases, apparent diffusion coefficient (ADC) could not be measured because of poor image quality. The ADC values of the ML were lowest, whereas those of Pleo were highest, similar to that observed for ve.

CONCLUSIONS

The Pleo tumors had lower K(trans) values and higher ve values, which are useful for differentiating them from the malignant tumors. Moreover, the ve was also useful for establishing a diagnosis of ML.

Dynamic contrast-enhanced MRI for differentiation of major salivary glands neoplasms, a 3-T MRI study

OBJECTIVES

Pre-operative differentiation of salivary gland neoplasms is of great importance. This study was designed to evaluate the use of dynamic contrast-enhanced MRI (DCE-MRI) for differentiation between malignant, Warthin and benign non-Warthin (BNW) neoplasms of major salivary glands.

METHODS

46 major salivary gland tumours (SGTs) underwent pre-operative DCE-MRI. Post-surgical histopathological evaluation showed 30 BNW, 6 Warthin and 10 malignant tumours. Time-signal intensity curves (TICs) were categorized as (a) Tpeak >43 s and washout ratio at 180 s (WR180) <4.6%; (b) Tpeak <43 s and WR >22%; (c) Tpeak >43 s and WR180 = 4.6-22.0%

RESULTS

Accuracy of Tpeak was 98.9% for differentiation between BNW and Warthin tumours, 83.7% between BNW and malignant and 80% between malignant and Warthin tumours. All Warthin tumours showed Tpeak ≤43 s, while one BNW had Tpeak <43 s. A Tpeak <63.5 s differentiated 8/10 (80%) malignant tumours from BNW tumours, whereas 4/30 of BNW tumours had a Tpeak <63.5 s. Two malignant tumours had Tpeak <43 s. WR180 had an accuracy of 100% for differentiation between Warthin and BNW tumours, 87.3% between BNW and malignant, and 93.3% between Warthin and malignant tumours. 29 (96.7%) BNW tumours had a washout <4.60%, while 8 (80%) malignant tumours had a washout >4.60%. All Warthin tumours had a WR180 >22%, while two malignant tumours had a WR180 >22%. 29/30 of BNW tumours demonstrated TIC curve Type A and 1 tumour demonstrated Type C. 6/10 of malignant tumours had TIC Type C, 2 had TIC Type A and 2 Type B. All Warthin tumours were categorized as Type B.

CONCLUSIONS

This study showed that DCE-MRI could be helpful in pre-operative differentiation of SGTs; especially for discrimination between Warthin and BNW tumours.

Adenoid cystic carcinoma of the buccal mucosa: A case report and review of the literature

Adenoid cystic carcinomas are deceptive malignancies that show slow growth and local invasion with recurrences seen many years after diagnosis. Upto 50% of these tumors occur in the intraoral minor salivary glands usually in the hard palate. Buccal mucosal tumors are relatively rare. We determined the incidence of buccal mucosal adenoid cystic carcinoma by reviewing the number of reported cases in the literature. This is the first article to analyze the occurrence of adenoid cystic carcinomas in the buccal mucosa through a review of 41 articles. Our review revealed 178 buccal mucosal adenoid cystic carcinomas among a total of 2,280 reported cases. We present a case of adenoid cystic carcinoma occurring in the left buccal mucosa of a 45-year-old female.