Minerva Becker

Specificity of parotid sialendoscopy

Objective To present our initial experience with sialendoscopy of the parotid duct.

Imaging of the larynx and hypopharynx

The purpose of this article is to review currently used imaging protocols for the evaluation of pathologic conditions of the larynx and hypopharynx, to describe key anatomic structures in the larynx and hypopharynx that are relevant to tumor spread and to discuss the clinical role of Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and PET CT in the pretherapeutic workup and posttherapeutic follow-up of patients with squamous cell carcinoma of this region. A detailed discussion of the characteristic neoplastic submucosal invasion patterns, including extension to the preepiglottic space, paraglottic space and laryngeal cartilages and the implications of imaging for tumor staging and treatment planning is provided. The present article also reviews less common tumors of this region, such as chondrosarcoma, lymphoma, minor salivary gland tumors and lipoma. As the majority of non-neoplastic conditions do not require imaging the role of CT and MRI is discussed in some particular situations, such as to delineate cysts and laryngoceles, abscess formation in inflammatory conditions, to evaluate laryngeal and hypopharyngeal involvement in granulomatous and autoimmune diseases, and to evaluate the extent of laryngeal fractures due to severe blunt trauma.

Submandibular diagnostic and interventional sialendoscopy: new procedure for ductal disorders

We present our initial experience with submandibular sialendoscopy, a new therapeutic approach for disorders of Whartons duct. We review the sialendoscopes used and discuss their respective merits. We evaluated and treated 129 consecutive patients with suspected ductal disorders. Diagnostic sialendoscopy was used for classifying ductal lesions as sialolithiasis, stenosis, sialodochitis, or polyps. Interventional sialendoscopy was used to treat these disorders. The type of endoscope used, the type of sialolith fragmentation and/or extraction device used, the total number of procedures, the type of anesthesia, and the number and size of the sialoliths removed were the dependent variables. The outcome variable was the endoscopic clearing of the ductal tree and resolution of symptoms. Diagnostic sialendoscopy was possible in 131 of 135 glands (97%), with an average (±SD) duration of 28 ± 15 minutes. Interventional sialendoscopy was attempted in 110 cases, with an average duration of 71 ± 41 minutes, with a success rate of 82%. Multiple sialendoscopies were necessary in 25% of cases. General anesthesia was used in 12% of cases. Submandibular gland resection was performed in 4%. The average size of the stones was 4.9 ± 2.9 mm. Multiple sialoliths were found in 31 cases (29%). Sialolith fragmentation was required in 26%. Larger and multiple stones often required longer and multiple procedures and general anesthesia, and more often resulted in failures. Semirigid endoscopes had a higher success rate (85%) than flexible sialendoscopes (54%). Complications were mostly minor, but were encountered in 10% of cases. Diagnostic sialendoscopy is a new technique for evaluating salivary duct disorders that is associated with low morbidity. Interventional sialendoscopy allows the extraction of sialoliths in most patients, thus preventing open gland excision.

New approaches in imaging of the brachial plexus

Imaging plays an essential role for the detection and analysis of pathologic conditions of the brachial plexus. Currently, several new techniques are used in addition to conventional 2D MR sequences to study the brachial plexus: the 3D STIR SPACE sequence, 3D heavily T2w MR myelography sequences (balanced SSFP=CISS 3D, True FISP 3D, bFFE and FIESTA), and the diffusion-weighted (DW) neurography sequence with fiber tracking reconstruction (tractography). The 3D STIR sequence offers complete anatomical coverage of the brachial plexus and the ability to slice through the volume helps to analyze fiber course modification and structure alteration. It allows precise assessment of distortion, compression and interruption of postganglionic nerve fibers thanks to the capability of performing maximum intensity projections (MIP) and multiplanar reconstructions (MPRs). The CISS 3D, b-SSFP sequences allow good visualization of nerve roots within the spinal canal and may be used for MR myelography in traumatic plexus injuries. The DW neurography sequence with tractography is still a work in progress, able to demonstrate nerves tracts, their structure alteration or deformation due to pathologic processes surrounding or located along the postganglionic brachial plexus. It may become a precious tool for the understanding of the underlying molecular pathophysiologic mechanisms in diseases affecting the brachial plexus and may play a role for surgical planning procedures in the near future.

Neoplastic invasion of laryngeal cartilage: radiologic diagnosis and therapeutic implications

Cross-sectional imaging plays an indispensable complementary role to endoscopy in the pretherapeutic workup of laryngeal and hypopharyngeal cancer. Both computed tomography and magnetic resonance imaging are suitable for the detection of neoplastic cartilage invasion. Although MRI, due to its high negative predictive value, is now generally considered to be the most suitable imaging method for pretherapeutic evaluation of cartilage invasion CT continues to be commonly performed in many centers for practical reasons. Recent studies have shown that CT may yield acceptable sensitivity for neoplastic invasion of laryngeal cartilage if the diagnostic criteria are selected and combined appropriately. False positive results are inevitable with both CT and MRI because reactive inflammation may lead to overestimation of neoplastic cartilage invasion.

Staging of laryngeal cancer: Endoscopy, computed tomography and magnetic resonance versus histopathology

An accurate pretherapeutic staging of laryngeal cancer is required for optimal treatment planning and for evaluation and comparison of the results of different treatment modalities. In this study, 45 consecutive patients with neoplasms of the larynx, treated surgically, were included in a prospective pretherapeutic staging protocol that included indirect laryngoscopy, direct microlaryngoscopy, contrast-enhanced computed tomography (CT) and Gd-DTPA-enhanced magnetic resonance imaging (MRI). The surgical specimens were cut in whole-organ slices parallel to the plane of the axial CT and MR images. The histologic findings were then compared with clinical findings, CT and MRI. These findings showed that clinical evaluation failed to identify tumor invasion of the laryngeal cartilages and extralaryngeal soft tissues, resulting in a low staging accuracy (55%). Many pT4 tumors were clinically understaged. The combination of clinical/endoscopic evaluation and either CT or MRI resulted in a significantly improved staging accuracy (80% vs 87%, respectively). MRI was significantly more sensitive but less specific than CT in detecting neoplastic cartilage invasion. MRI tended to overestimate neoplastic cartilage invasion to possibly result in overtreatment, while CT was found to underestimate neoplastic cartilage invasion and could lead to inadequate therapeutic decisions.

Impact of cartilage invasion on treatment and prognosis of laryngeal cancer

Invasion of laryngeal cartilage has long been considered as a contraindication to radiation treatment and to all types of conservation surgery. With the advent of axial imaging techniques clarification of the submucosal extent of disease became possible. However, controversies regarding diagnosis (preferred modality, accuracy of detection of cartilage invasion) and treatment of cartilage invasion (Is cartilage invasion really a contraindication for irradiation treatment?) arose. Based on currently accepted criteria, CT appears to be more specific in detecting neoplastic cartilage invasion than MRI, but tends to underestimate invasion and may therefore result in undertreatment. Magnetic resonance has a higher sensitivity than CT for detection of cartilage invasion. The superiority of MRI lies in its ability to detect intracartilaginous tumor spread. Unfortunately, MR findings suggesting neoplastic cartilage invasion may be false positive in a considerable number of instances. Two MRI-dependent parameters appear to be significant as a prognostic factor for success of radiation therapy: tumor volume and abnormal MR signal pattern in cartilage. Minimal abnormal MR signal patterns in cartilage in patients with small tumors (under 5 cc) does not appear to be a very ominous finding for tumor recurrence after radiation therapy. On the other hand, abnormal MR signal pattern in cartilage combined with large tumor volume (above 5 cc) appears to worsen the prognosis significantly. If voice conservation surgery is being considered, MR imaging is useful for assesing those structures (such as cartilages) whose involvement would contraindicate partial laryngectomy. Magnetic resonance imaging appears to be the optimal method of examination in cooperative patients. If MRI fails or if it is contraindicated, CT may still be recommended. The radiologists experience with CT or MRI also determines the choice between the two modalities.

Detection and quantification of focal uptake in head and neck tumours: 18 F-FDG PET/MR versus PET/CT

PurposeOur objectives were to assess the quality of PET images and coregistered anatomic images obtained with PET/MR, to evaluate the detection of focal uptake and SUV, and to compare these findings with those of PET/CT in patients with head and neck tumours.MethodsThe study group comprised 32 consecutive patients with malignant head and neck tumours who underwent whole-body 18F-FDG PET/MR and PET/CT. PET images were reconstructed using the attenuation correction sequence for PET/MR and CT for PET/CT. Two experienced observers evaluated the anonymized data. They evaluated image and fusion quality, lesion conspicuity, anatomic location, number and size of categorized (benign versus assumed malignant) lesions with focal uptake. Region of interest (ROI) analysis was performed to determine SUVs of lesions and organs for both modalities. Statistical analysis considered data clustering due to multiple lesions per patient.ResultsPET/MR coregistration and image fusion was feasible in all patients. The analysis included 66 malignant lesions (tumours, metastatic lymph nodes and distant metastases), 136 benign lesions and 470 organ ROIs. There was no statistically significant difference between PET/MR and PET/CT regarding rating scores for image quality, fusion quality, lesion conspicuity or anatomic location, number of detected lesions and number of patients with and without malignant lesions. A high correlation was observed for SUVmean and SUVmax measured on PET/MR and PET/CT for malignant lesions, benign lesions and organs (ρ = 0.787 to 0.877, p < 0.001). SUVmean and SUVmax measured on PET/MR were significantly lower than on PET/CT for malignant tumours, metastatic neck nodes, benign lesions, bone marrow, and liver (p < 0.05). The main factor affecting the difference between SUVs in malignant lesions was tumour size (p < 0.01).ConclusionIn patients with head and neck tumours, PET/MR showed equivalent performance to PET/CT in terms of qualitative results. Comparison of SUVs revealed an excellent correlation for measurements on both modalities, but underestimation of SUVs measured on PET/MR as compared to PET/CT.

FDG-PET/CT pitfalls in oncological head and neck imaging

ObjectivesPositron emission tomography-computed tomography (PET/CT) with fluorine-18-fluorodeoxy-D-glucose (FDG) has evolved from a research modality to an invaluable tool in head and neck cancer imaging. However, interpretation of FDG PET/CT studies may be difficult due to the inherently complex anatomical landmarks, certain physiological variants and unusual patterns of high FDG uptake in the head and neck. The purpose of this article is to provide a comprehensive approach to key imaging features and interpretation pitfalls of FDG-PET/CT of the head and neck and how to avoid them.MethodsWe review the pathophysiological mechanisms leading to potentially false-positive and false-negative assessments, and we discuss the complementary use of high-resolution contrast-enhanced head and neck PET/CT (HR HN PET/CT) and additional cross-sectional imaging techniques, including ultrasound (US) and magnetic resonance imaging (MRI).ResultsThe commonly encountered false-positive PET/CT interpretation pitfalls are due to high FDG uptake by physiological causes, benign thyroid nodules, unilateral cranial nerve palsy and increased FDG uptake due to inflammation, recent chemoradiotherapy and surgery. False-negative findings are caused by lesion vicinity to structures with high glucose metabolism, obscuration of FDG uptake by dental hardware, inadequate PET scanner resolution and inherent low FDG-avidity of some tumours.ConclusionsThe interpreting physician must be aware of these unusual patterns of FDG uptake, as well as limitations of PET/CT as a modality, in order to avoid overdiagnosis of benign conditions as malignancy, as well as missing out on actual pathology.Teaching points• Knowledge of key imaging features of physiological and non-physiological FDG uptake is essential for the interpretation of head and neck PET/CT studies.• Precise anatomical evaluation and correlation with contrast-enhanced CT, US or MRI avoid PET/CT misinterpretation.• Awareness of unusual FDG uptake patterns avoids overdiagnosis of benign conditions as malignancy.

Histopathology of Submandibular Glands Removed for Sialolithiasis

We reviewed the clinical history of 48 consecutive patients who underwent submandibular gland removal for radiologically proven sialolithiasis. The specimens were examined by a pathologist blinded to the clinical data. A histopathologic classification into 1 of 3 grades was established by evaluating the degrees of atrophy, fibrosis, and inflammation. A correlation between the clinical and pathological variables was sought in order to define clinical variables that would predict abnormal submandibular glands that required extirpation. A significant percentage of the submandibular glands exhibited normal histologic findings. The patients with normal submandibular glands had a clinical evolution similar to that of other patients with severely damaged glands. The only clinical variable that correlated with increased histopathologic alteration was the patients age. In view of the newly available diagnostic and therapeutic techniques for sialolithiasis, a conservative attitude to submandibular gland resection appears justified.