Diffusion-weighted MRI in head and neck cancer

Does Diffusion Magnetic Resonance Imaging (DWI) has Role in Irradiated Laryngeal Carcinoma?

DWI involves acquisition of signal of movement of water proton in cellular spaces of body (Brownian motion). It includes qualitative method either restricted or facilitated and quantitive method which is apparent diffusion coefficient value(ADC) which is related to proportion of extracellular and intracellular components of the tissue., ADC is calculated with use of at least two b value more accurate using more DWI with different b value,ADC levels is low in increased tissue cellularity, as malignancy., ADC levels is high in non-tumoral tissue alterations such as direct endoscopy oedema, radiotherapy necrosis are expected to have minimal cellularity. ADC is most accurate in the detection of malignancy versus tissue edema or radionecrosis the aim of study to assess value of ADC as regarding measuring sensitivity and specificity and accuracy to differentiate tumor recurrence from radionecrosis. This study includes 36 patients who were suspected patients of tumor recurrence after radiotherapy; it is a prospective randomized comparative clinical trial. The patients were assessed using direct laryngoscopic examination under general anaesthesia and biopsy, and diffusion weighted image on the neck (b0 and b1000), ADC map and ADC value measured al lesion and normal tissues and compared with pathology results. ADC value (mean 0.93 ± 0.30 X 10-3 mm2/s) in patients had recurrent carcinoma was significantly lower (P < .0001) than the mean ADC of normal tissue in the same patients (1.26 ± 0.134) while mean ADC of tumour recurrence (P < .0001) was lower than mean ADC value of radio necrosis (1.63 ± 0.21 × 10-3 mm2/s). MRI ADC value is a sensitive and non-invasive method in detection of a recurrent laryngeal lesion from radionecrosis.

The added value of pretreatment DW MRI in characterization of salivary glands pathologies

OBJECTIVE

To evaluate the added value of diffusion weighted magnetic resonance imaging (DW-MRI) in characterization of salivary gland lesions.

STUDY DESIGN

A prospective study was carried out between January 2013, and March 2015.

METHODS

The study included 46 patients. The consultant radiologist, who reviewed the scans to comment on the apparent diffusion coefficient (ADC) value and ADC histogram was blind to the suspected pathology. Radiological findings were then compared to clinical and histological findings.

RESULTS

The diagnostic performance of DW-MRI for identification of malignant lesions showed that the sensitivity, specificity, and positive and negative prediction value were 100%, 92%, 91.3%, and 100%, respectively.

CONCLUSION

The specific ability of DW-MRI to probe tissue microstructures is an interesting complement to the currently used imaging procedures in the characterization, and even grading of malignancies. ADC mapping is an easy, cost effective promising tool that has neither radiation exposure, nor amalgam artifacts and can be used in helping characterization of salivary glands lesions.

LEVEL OF EVIDENCE

1B.

Utility of apparent diffusion coefficient in characterization of different sinonasal pathologies

BACKGROUND

Sinonasal lesions are a heterogeneous group of lesions that span from a tumor to tumor-like nature. Characterization of such cases preoperatively can improve the surgical control and the overall outcome of these patients.

OBJECTIVE

In this prospective study, we aimed at evaluation of the role of apparent diffusion coefficient (ADC) in the differentiation between benign and malignant sinonasal lesions.

SUBJECTS AND METHODS

All patients scheduled to have sinonasal surgical intervention at Ain Shams University Hospitals, Cairo, Egypt, were enrolled. Diffusion-weighted (DW) magnetic resonance imaging (MRI) with calculation of ADC were done for all cases. Radiologic findings were then compared with histologic findings, and the sensitivity, specificity, negative and positive predictive values (PPVs) of the conventional MRI, DW-MRI, and ADC value in differentiation of benign from malignant sinonasal lesions were then calculated.

RESULTS

There were 59 patients with median age of 43 years old. There were 20 cases of inflammatory lesions, 16 cases of benign tumors, and 23 cases of malignant lesions. The ADC values of all cases ranged from 0.4 × 10(-3) to 2 × 10(-3) (median = 1.5 × 10(-3)). The median ADC value for the malignant lesions was 0.6 × 10(-3), whereas that for the inflammatory conditions was 1.6 × 10(-3) and that for the benign tumors was 1.5 × 10(-3) with a highly significant difference (p < .001). Analysis of the conventional MRI and DW-MRI to differentiate between malignant and benign lesions showed that the sensitivity, specificity, PPV, and negative predictive value (NPV) were 100%, 97%, 96%, and 100% and 91%, 97%, 95%, and 95%, respectively.

CONCLUSION

DW-MRI did not add significantly to the information gained from conventional MRI. It should be considered complimentary only to standard MRI in uncertain cases when malignancy is still a concern.

The role of diffusion-weighted magnetic resonance imaging in the diagnosis, lymph node staging and assessment of treatment response of head and neck cancer

Standard magnetic resonance imaging (MRI) and computed tomography continue to be the imaging modalities of choice in staging and reviewing patients with head and neck cancer. Diffusion-weighted MRI (DW-MRI) is an advanced imaging modality that records the molecular diffusion of protons and thus provides an opportunity to further assess tissue character. Interest in DW-MRI of the head and neck continues to grow, especially its application to the assessment and treatment of head and neck cancer. We highlight the potential role of DW-MRI in the delineation, characterization, and lymph node staging of head and neck tumours. Furthermore, we discuss the ability of DW-MRI to provide a real opportunity to differentiate post-treatment tumour recurrence from chemoradiotherapy-induced local tissue changes. The future impact of these findings upon the clinical practice of the head and neck surgeon is discussed.

Prognostic factors in advanced pharyngeal and oral cavity cancer; significance of multimodality imaging in terms of 7th edition of TNM

As with most cancers the prognosis in pharyngeal and oral cavity cancer largely depends on tumour stage. Physical examination, including endoscopy should be combined with technical radiologic imaging to record the precise extent of tumour. The TNM staging system of the head and neck region is, in fact, an anatomic staging system that describes the anatomic extent of the primary tumour as well as the involvement of regional lymph nodes and distant metastases. Modifications in the TNM staging system should consider not only the expert opinions and published reports in the literature but the technical advances in technology for improved assessment of tumour extent and the shifting paradigms in therapeutic strategies. “T” stage of the tumour is defined by its size, the depth of the invasion and the involvement of vital structures. In the 7th edition of TNM classification, for stage T4 tumors (larger than 4 cm), subcategories a and b were introduced to indicate the involvement of vital structures and their suitability for surgical resection (except for nasopharynx cancer). Nodal metastasis is the most important predictor of outcome for squamous cell cancer of the head and neck.

Better and more reliable methods of pretreatment tumour assessment are therefore crucial to ensure that the clinical assessment of tumor approximates its actual pathologic extent.

CT and MRI are both useful for assessing extensions of pharyngeal- and oral cavity cancer in advanced stage. MRI is superior in visualizing most primary tumour sites.

Cervical lymph node evaluation and diagnosis

This article discusses the rationale for imaging cervical lymph nodes and reviews nodal anatomy and common drainage patterns, imaging features of pathologic lymph nodes, and the advantages of various imaging modalities available for evaluation and diagnosis of the lymph nodes.

Aplicações da técnica de difusão por RM em cabeça e pescoço: um olhar além da anatomia

DWI é uma técnica totalmente não invasiva que tem sido utilizada com sucesso por muitos anos em imagens do cérebro e recentemente incluída como parte da avaliação de outros sistemas, por exemplo, no abdome e pelve e na cabeça e pescoço. Apesar de a DWI e a medida dos valores de ADC serem capazes de fornecer informações de tipos histológicos específicos de tumores, a maioria dos centros de imagem ainda não os adotaram como parte da rotina na avaliação da cabeça e pescoço. A medida de ADC demonstrou ser útil para discriminar tipos específicos de tumores histológicos, especialmente para diferenciar lesões benignas sólidas de massas malignas, importante na avaliação de linfonodos cervicais, principalmente para diferenciar processos nodais benignos de malignos, para diferenciar as alterações pós-radioterapia de tumor residual e ter uso potencial para predizer sucesso terapêutico. Além disso, DWI/ADC parece ser um método mais seguro e mais acessível, considerando a ausência de radiação ionizante e ao maior custo do FDG-PET na localização de tumores e diferenciar massas benignas de malignas. Com todas essas vantagens e potencialidades, DWI/ADC certamente fará parte da rotina na avaliação por imagem da cabeça e pescoço.

Squamous cell carcinoma of the head and neck-The role of diffusion and perfusion imaging in tumor recurrence and follow-up

Computed tomography and magnetic resonance imaging-based techniques of functional imaging are proven to be sensitive and reliable tools for detection and staging of head and neck cancer. These new techniques enable to visualize and differentiate subtle pathologic changes before they become evident on standard cross-sectional images. However, it is their role in evaluating possible recurrence and estimation of treatment response that holds the biggest promise. This article describes the role and usefulness of diffusion and perfusion in detecting recurrence and follow-up in patients with head and neck squamous cell carcinoma.

Newer imaging techniques in head and neck cancer

Computerized tomography (CT), Magnetic Resonance Imaging form the backbone of head and neck cancer imaging. This review describes the role of newer functional imaging techniques like diffusion weighted MR imaging and perfusion imaging in head and neck cancers. A review of the current role of PET-CT in head and neck tumors is also included in this article.

Functional imaging of head and neck cancers

PURPOSE OF REVIEW

Functional imaging including single photon emission computed tomography, PET and MRI techniques in head and neck squamous cell cancer allows disease characterization beyond structure and morphology.

RECENT FINDINGS

In patients without clinical signs of lymph node involvement, sensitivity of fluoro-2-deoxy-D-glucose PET is only 50%. This has led to the use of sentinel lymph node scintigraphy that seems to be a valid alternative to elective stage dissection. Additionally, the use of single-photon emission computed tomography-computed tomography imaging enables a more accurate localization of the sentinel lymph node scintigraphy. The fluoro-2-deoxy-D-glucose uptake intensity of the head and neck squamous cell carcinoma sites is related to locoregional control and overall survival. In case of suspicion for residual or recurrent head and neck squamous cell carcinoma after surgery or (chemo)radiotherapy, fluoro-2-deoxy-D-glucose-PET has a high sensitivity and seems to be cost-effective in selecting patients for direct laryngoscopy. Diffusion-weighted MRI in combination with size and morphological criteria is a strong predictor of presence of malignant lymph nodes. Initial reports indicate the use of diffusion-weighted imaging for response assessment as early as 1 week after beginning of radiochemotherapy. Perfusion MRI is studied for the measurement of drug effects on tumour (micro)vascularity and capillary permeability.

SUMMARY

Functional imaging improves the initial staging and the detection of residual or recurrent disease following therapy.

Head and neck squamous cell carcinoma: value of diffusion-weighted MR imaging for nodal staging

PURPOSE

To evaluate diffusion-weighted (DW) magnetic resonance (MR) imaging, as compared with turbo spin-echo MR imaging, for the detection of nodal metastases in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

The study was approved by the ethics committee, and patients gave written informed consent. Before undergoing surgery, 33 consecutive patients underwent 1.5-T MR imaging, including DW imaging performed with a wide range of b values (0-1000 sec/mm(2)). The apparent diffusion coefficients (ADCs) of lymph nodes 4 mm or greater in short-axis diameter depicted on images obtained with b values of 0 and 1000 sec/mm(2) were calculated. After topographic correlation, the lymph nodes were evaluated microscopically with prekeratin immunostaining. The optimal ADC thresholds for discriminating between metastatic and benign lymph nodes were determined. The sensitivity, specificity, and accuracy of DW imaging were calculated separately-on per-lymph-node and per-neck-level bases-for all lymph nodes and for supracentimeter and subcentimeter lymph nodes and were compared with corresponding turbo spin-echo MR imaging values.

RESULTS

Correlation of histopathologic and radiologic findings was possible for 301 lymph nodes. The ADC derived from the signal intensity averaged across images obtained with b values of 0 and 1000 sec/mm(2) (ADC(b0-1000)) was 1.19 x 10(-3) mm(2)/sec +/- 0.22 (standard deviation) for benign lymph nodes and 0.85 x 10(-3) mm(2)/sec +/- 0.27 for malignant lymph nodes (P < .0001). With an optimal ADC(b0-1000) threshold of 0.94 x 10(-3) mm(2)/sec, 84% sensitivity, 94% specificity, and 91% accuracy for differentiation of malignant versus benign status of each lymph node and 94% sensitivity, 97% specificity, and 97% accuracy for differentiation at each neck level were achieved. Compared with turbo spin-echo imaging, DW imaging had higher sensitivity (76% vs 7%) but slightly lower specificity (94.0% vs 99.5%) for detection of subcentimeter nodal metastases.

CONCLUSION

DW imaging performed with ADC(b0-1000) values had higher accuracy than turbo spin-echo MR imaging in nodal staging, providing added value in the detection of subcentimeter nodal metastases.

New directions in head and neck imaging

Computerized tomography (CT) and magnetic resonance imaging (MRI), positron emission tomography (PET) and the hybrid modality of PET/CT are sensitive and reliable tools for detection and staging of head and neck cancers. This article describes the role of PET/CT in initial staging of head and neck squamous cell carcinoma, the utility of CT/MR perfusion imaging in qualitative analysis of tumor tissue, and the usefulness of diffusion weighted MR and dynamic contrast-enhanced MR imaging in head and neck oncological imaging.

Paranasal sinus imaging

Endonasal surgery is currently extending its application beyond inflammatory sinonasal lesions to successfully treat both benign and malignant neoplasms. This progression has been possible by the detailed information provided by imaging techniques (CT, MRI and PET). Inflammatory diseases are the "domain" of CT. CT provides excellent details about the thin bony sinonasal walls separating the ethmoid from the anterior skull base and the orbit. Benign and malignant neoplasms are the "domain" of MRI because the tumor is more easily separated from adjacent structures, the periosteal linings (periorbita, dura mater) and perineural spread can be accurately shown. Whereas MRI precisely assess pre-treatment tumor extent, early submucosal local recurrences are difficult to demonstrate because of post-treatment changes of the anatomy and of the signal of treated tissues. Though diffusion-weighted imaging and dynamic contrast-enhanced techniques are promising developments, PET-CT may overcome the limits of morphological MRI.