Magnetic resonance imaging of parotid gland tumors: a pictorial essay.

Imaging of parotid gland tumors is challenging due to the wide variety of differential diagnoses. Malignant parotid tumors can have very similar features to benign ones, such as slow growth and displacement instead of infiltration of neighboring structures. Malignant and benign tumors may therefore not be clinically distinguishable. Correct characterization of parotid tumors (i.e., benign or malignant) determines preoperative treatment planning and is important in optimizing the individualized surgical plan. Magnetic resonance imaging (MRI) is the imaging modality of choice for evaluation of suspected parotid gland lesions and differentiation between benign and malignant lesions. Certain conventional MRI features can suggest whether a mass is more likely to be a benign or low-grade malignancy or a high-grade malignancy and adding diffusion-weighted imaging or advanced MRI techniques like perfusion can aid in this distinction. Morphological features seen on MRI, such as low signal on T2-w, infiltrative changes or ill-defined margins, change over time and diffusion restriction can point to the malignant nature of the lesion. MRI is useful for detection and localization of the lesion(s), and associated findings like perineural spread of tumor, lymph node involvement and infiltrative changes of the surrounding tissues. In this pictorial essay, we present selected images of a variety of benign and malignant parotid tumors and emphasize the MRI features that may be useful in their characterization.

Full core technology versus notch sampling technology: evaluation of the diagnostic accuracy and the risk of a pneumothorax after transthoracic needle biopsy of suspicious lung lesions.

BACKGROUND: Percutaneous needle biopsy of the lung (PCBL) under image guidance has become a safe and effective minimal invasive method to obtain a specimen related histological diagnosis of pulmonary lesions. PURPOSE: To evaluate the diagnostic yield and safety of two different coaxial biopsy technologies: full core and notch sampling technology. The former allowing the removal of full punch cylinders and the latter using a cutting-edge mechanism. MATERIAL AND METHODS: A retrospective analysis of 48 consecutive PCBL procedures has been carried out for this prognostic study, involving patients with a documented pulmonary nodule or mass lesion on previous computed tomography (CT) scans. The study population included 38 men and 10 women (mean age = 67 years). Of these 48 patients who underwent a procedure with a co-axial cutting system, 24 have been performed with notch sampling technology and 24 with full core technology. RESULTS: Out of the 48 biopsy procedures, 46 yielded specimens were adequate for histopathological evaluation, consistent with a technical success rate of 96%. The most common induced image-guided biopsy complication was a pneumothorax, occurring in 14 patients (35%). Seven patients with a pneumothorax were attributed to the full core technology and seven to the notch sampling technology (odds ratio = 1, 95% confidence interval = 0.28-3.51, P = 1). CONCLUSION: In the setting of full core versus notch sampling percutaneous CT-guided coaxial needle biopsy of the lung, no significant difference in the diagnostic accuracy and the incidence of pneumothoraces could be shown, while both technologies have an excellent diagnostic performance.

Deficiency of Fhl2 leads to delayed neuronal cell migration and premature astrocyte differentiation.

The four and a half LIM domains protein 2 (Fhl2) is an adaptor protein capable of mediating protein-protein interactions. Here, we report for the first time phenotypic changes in the brain of Fhl2-deficient mice. We showed that Fhl2 is expressed in neural stem cells, precursors and mature cells of neuronal lineage. Moreover, Fhl2 deficiency leads to delayed neuroblast migration in vivo, premature astroglial differentiation of neural stem cells (NSCs) in vitro, and a gliosis-like accumulation of glial fibrillary acidic protein (GFAP)-positive astrocytes in vivo that substantially increases with age. Collectively, Fhl2-deficiency in the brain interrupts the maintenance and the balanced differentiation of adult NSCs, resulting in preferentially glial differentiation and early exhaustion of the NSC pool required for adult neurogenesis.

Radiologists and nuclear medicine physicians are looking forward to a cross-curricular training.

OBJECTIVES: To obtain an overview of the attitudes toward interdisciplinary further education of residents and consultants in radiology and nuclear medicine and preferences regarding a future joint training curriculum in Switzerland. METHODS: A 34-item questionnaire was sent electronically (SurveyMonkey online survey tool) to 1244 radiologists and nuclear physicians (residents and consultants) in Switzerland. The items asked about the motivation for further education in each other's specialty and preferences regarding a joint further education curriculum in radiology and nuclear medicine. RESULTS: Overall, 370 questionnaires were analyzed (370/1244, 30%). There were 280 (76%) board-certified physicians in either radiology (238/370, 64%) or nuclear medicine (42/370, 12%) and 65 (18%) residents (radiology 54/370, 15%; nuclear medicine 11/370, 3%). More than half of all residents (34/65, 52%) stated their conviction that a wide range of expertise in both disciplines could be fully guaranteed through adequate cross-curricular training. For responders already at a consultant level in radiology or nuclear medicine, the willingness to undergo further training in each other's specialty significantly increased with a shorter training period. The preferred option for a possible future joint training curriculum was a combination of a 5-year radiology training program with 2 years of further training in nuclear medicine. CONCLUSIONS: Both residents and board-certified physicians in Switzerland are highly interested in a cross-curricular training curriculum in radiology and nuclear medicine. KEY POINTS: • A systematic survey was conducted to obtain information on interest in cross-curricular training in radiology and nuclear medicine and preferences regarding a future joint training curriculum. • More than half of radiology and nuclear medicine residents would be interested in further training in the other specialty. • There is a strong desire for a shorter training program when combining training in both radiology and nuclear medicine.

Diagnostic value of 18F-FDG PET/CT versus diffusion-weighted MRI in detection of residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal squamous cell carcinoma: A prospective study.

BACKGROUND: Despite advances in treatment, residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal squamous cell carcinoma (SCC) remain a challenge in clinical management and require accurate and timely detection for optimal salvage therapy. This study aimed to compare the diagnostic value of Fluorine 18 (18F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) in detecting residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal SCC. METHODS: A prospective study was conducted on 30 patients who presented with new symptoms after definitive (chemo) radiotherapy for laryngeal (n = 21) and hypopharyngeal (n = 9) carcinoma. Both 18F-FDG PET/CT and DW-MRI were performed and histopathologic analysis served as the standard of reference. RESULTS: Histopathology showed 20 patients as positive and 10 as negative for tumors. 18F-FDG PET/CT detected all tumors correctly but was falsely positive in one case. DW-MRI detected tumors in 18 out of 20 positive patients and correctly excluded tumors in all negative patients. The sensitivity and specificity of 18F-FDG PET/CT were 100% and 90%, respectively, while the values for DW-MRI were 90% and 100%, respectively. CONCLUSIONS: The study concludes that 18F-FDG PET/CT is slightly superior to DW-MRI in detecting residual or recurrent tumors after definitive (chemo) radiotherapy for laryngeal and hypopharyngeal SCC. The combined use of 18F-FDG PET/CT and DW-MRI can potentially improve specificity in therapy response evaluation.

The Value of APTw CEST MRI in Routine Clinical Assessment of Human Brain Tumor Patients at 3T.

BACKGROUND: With fast-growing evidence in literature for clinical applications of chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI), this prospective study aimed at applying amide proton transfer-weighted (APTw) CEST imaging in a clinical setting to assess its diagnostic potential in differentiation of intracranial tumors at 3 tesla (T). METHODS: Using the asymmetry magnetization transfer ratio (MTRasym) analysis, CEST signals were quantitatively investigated in the tumor areas and in a similar sized region of the normal-appearing white matter (NAWM) on the contralateral hemisphere of 27 patients with intracranial tumors. Area under curve (AUC) analyses were used and results were compared to perfusion-weighted imaging (PWI). RESULTS: Using APTw CEST, contrast-enhancing tumor areas showed significantly higher APTw CEST metrics than contralateral NAWM (AUC = 0.82; p < 0.01). In subgroup analyses of each tumor entity vs. NAWM, statistically significant effects were yielded for glioblastomas (AUC = 0.96; p < 0.01) and for meningiomas (AUC = 1.0; p < 0.01) but not for lymphomas as well as metastases (p > 0.05). PWI showed results comparable to APTw CEST in glioblastoma (p < 0.01). CONCLUSIONS: This prospective study confirmed the high diagnostic potential of APTw CEST imaging in a routine clinical setting to differentiate brain tumors.

Imaging in head and neck cancers: Update for non-radiologist.

Head and neck cancer (HNC) is the fifth most frequent cancer worldwide and associated with significant morbidity. Along with clinical examination and endoscopic evaluation, imaging plays an important role in pre- and posttherapeutic evaluation of patients with HNC. Cross-sectional Imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography / computed tomography (PET/CT) are routinely used in the assessment of these patients. This review provides an overview of the various cross-sectional imaging modalities used in the evaluation of HNC and will give a short summary of the latest imaging technologies regarding head and neck cancer diagnosis.

Evidence for the Vascular Origin of Benign Enhancing Foramen Magnum Lesions via Intraoperative Photographs: Case Report and Review of the Literature.

A small, benign enhancing lesion posterior to the intracranial vertebral artery at the foramen magnum is a recently described image-based entity and believed to represent varix or ganglion. We report on an individual who underwent surgery due to a hybrid neurofibroma/schwannoma of the trigeminal nerve and additionally presented a small gadolinium-enhancing lesion in the right spinal canal at the level of the craniocervical junction (CCJ). The intraoperative finding of this enhancing lesion most likely represents the lateral internal vertebral venous plexus which does not require follow up or surgical excision.

Comparison of diffusion-weighted MR imaging and 18F Fluorodeoxyglucose PET/CT in detection of residual or recurrent tumors and delineation of their local spread after (chemo) radiotherapy for head and neck squamous cell carcinoma.

PURPOSE: To compare the diagnostic accuracy of diffusion-weighted magnetic resonance imaging (DW-MRI) and fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in detection of residual or recurrent tumors and their local extension in patients with head and neck squamous cell carcinoma after treatment with (chemo) radiotherapy (CRT). METHOD: Twenty-five patients (17 men, 8 women, median age 64 years, range 49-79) who underwent surgical salvage for residual or recurrent tumors after CRT were included. The histopathologic analysis after the surgical salvage served as the gold standard. RESULTS: Both DW-MRI and 18F-FDG PET/CT had a sensitivity of 92 % (23/25) in the detection of residual or recurrent tumors. MRI had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting perineural spread of 62 % (5/8), 88 % (15/17), 71 % (5/7) and 83 % (15/18), respectively; in comparison, PET/CT did not detect any cases of perineural spread. The sensitivity, specificity, PPV and NPV of MRI in detecting muscle infiltration was 75 % (9/12), 77 % (10/13), 75 % (9/12) and 77 % (10/13) respectively, while the values for 18F-FDG PET/CT were 58 % (7/12), 69 % (9/13), 64 % (7/11) and 64 % (9/14). CONCLUSIONS: DW-MRI- and 18F-FDG PET/CT-imaging have an identical detection rate of residual or recurrent tumors after (chemo) radiotherapy. MRI has a higher sensitivity in detecting local perineural spread, has a better accuracy in the detection of muscle infiltration and more accurately correlates the lesion size to the histopathologic specimen.

Nuevos factores de riesgo de hemorragia pulmonar que complican la biopsia pulmonar guiada por TC en técnica coaxial / Novel risk factors of pulmonary hemorrhage complicating CT-guided lung biopsy in coaxial technique

Objetivos: Evaluar la frecuencia y gravedad de la hemorragia parenquimatosa pulmonar tras la biopsia pulmonar con aguja transtorácica coaxial, según factores de procedimiento, aún no descritos en la literatura. El objetivo de este estudio fue determinar si la elección de la tecnología de biopsia coaxial, el posicionamiento del paciente y la dignidad de la lesión son tres nuevas variables que influyen en el riesgo de hemorragia parenquimatosa tras biopsias coaxiales de pulmón. Métodos: Se revisaron retrospectivamente los registros de 117 pacientes que se sometieron a biopsias con aguja transtorácica del pulmón entre enero de 2018 y abril de 2020. El resultado primario fue la hemorragia pulmonar. Se ha utilizado un sistema de clasificación para clasificar la hemorragia parenquimatosa pulmonar: Grado 0 - Grado 3. Se evaluaron tres variables novedosas relacionadas con el paciente, la técnica y la lesión como predictores de hemorragia pulmonar: tecnología de biopsia coaxial, posición del paciente y dignidad de la lesión. Resultados: De los 117 pacientes, 18 (15,4%) pacientes con tecnología de biopsia coaxial de corte, versus 29 (24,8%) pacientes con tecnología coaxial de núcleo completo mostraron hemorragia significativa en las exploraciones de control posteriores a la biopsia. (IC del 95% 0,06-0,33, p <0,0001). No hubo diferencias significativas en la hemorragia pulmonar entre el diagnóstico histológico benigno y maligno (IC 95% 0,84-4,44, p = 0,1199) y la posición del paciente en decúbito prono o supino (IC 95%: 0,57-2,57, p = 0,6232). Conclusiones: La incidencia y gravedad de la hemorragia pulmonar depende de la tecnología de biopsia coaxial utilizada; siendo mayor en pacientes sometidos a una biopsia con tecnología full-core y menor después del uso de tecnología de corte. En este estudio de pronóstico no se estableció una correlación significativa entre la hemorragia pulmonar parenquimatosa y la posición del paciente o la dignidad de la lesión

Objectives: To evaluate the frequency and severity of pulmonary parenchymal hemorrhage after coaxial transthoracic needle biopsy of the lung, according to procedural factors, not yet described in literature. The aim of this study was to determine whether the choice of the coaxial biopsy technology, patient positioning and the lesion dignity are three new variables influencing the risk of parenchymal hemorrhage after coaxial biopsies of the lung. Methods: Records from 117 patients who underwent transthoracic needle biopsies of the lung between January 2018 and April 2020 have been retrospectively reviewed. The primary outcome was pulmonary hemorrhage. A grading system has been used to classify pulmonary parenchymal hemorrhage: Grade 0 ­ Grade 3. Three novel patient, technique and lesion-related variables were evaluated as predictors of pulmonary hemorrhage: coaxial biopsy technology, patient positioning and lesion dignity. Results: Out of the 117 patients, 18 (15,4%) patients with cutting coaxial biopsy technology, versus 29 (24,8%) patients with full core coaxial technology showed significant hemorrhage on the post-biopsy control scans. (95% CI 0,06-0,33, p<0,0001). No significant difference in pulmonary hemorrhage between benign and malignant histological diagnosis (95% CI 0,84-4,44, p=0,1199) and prone or supine patient positioning (95% CI: 0,57-2,57, p= 0,6232) was found. Conclusions: The incidence and severity of pulmonary hemorrhage depends on the coaxial biopsy technology used; being higher in patients undergoing a biopsy with full-core technology and lower after the use of cutting technology. No significant correlation between parenchymal pulmonary hemorrhage and patient positioning or lesion dignity was established in this prognostic study.