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.

Arterial Spin Labeling (ASL) in Neuroradiological Diagnostics - Methodological Overview and Use Cases.

BACKGROUND: Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI)-based technique using labeled blood-water of the brain-feeding arteries as an endogenous tracer to derive information about brain perfusion. It enables the assessment of cerebral blood flow (CBF). METHOD: This review aims to provide a methodological and technical overview of ASL techniques, and to give examples of clinical use cases for various diseases affecting the central nervous system (CNS). There is a special focus on recent developments including super-selective ASL (ssASL) and time-resolved ASL-based magnetic resonance angiography (MRA) and on diseases commonly not leading to characteristic alterations on conventional structural MRI (e. g., concussion or migraine). RESULTS: ASL-derived CBF may represent a clinically relevant parameter in various pathologies such as cerebrovascular diseases, neoplasms, or neurodegenerative diseases. Furthermore, ASL has also been used to investigate CBF in mild traumatic brain injury or migraine, potentially leading to the establishment of imaging-based biomarkers. Recent advances made possible the acquisition of ssASL by selective labeling of single brain-feeding arteries, enabling spatial perfusion territory mapping dependent on blood flow of a specific preselected artery. Furthermore, ASL-based MRA has been introduced, providing time-resolved delineation of single intracranial vessels. CONCLUSION: Perfusion imaging by ASL has shown promise in various diseases of the CNS. Given that ASL does not require intravenous administration of a gadolinium-based contrast agent, it may be of particular interest for investigations in pediatric cohorts, patients with impaired kidney function, patients with relevant allergies, or patients that undergo serial MRI for clinical indications such as disease monitoring. KEY POINTS: · ASL is an MRI technique that uses labeled blood-water as an endogenous tracer for brain perfusion imaging.. · It allows the assessment of CBF without the need for administration of a gadolinium-based contrast agent.. · CBF quantification by ASL has been used in several pathologies including brain tumors or neurodegenerative diseases.. · Vessel-selective ASL methods can provide brain perfusion territory mapping in cerebrovascular diseases.. · ASL may be of particular interest in patient cohorts with caveats concerning gadolinium administration..

Modern preoperative imaging and functional mapping in patients with intracranial glioma.

Magnetic resonance imaging (MRI) in therapy-naïve intracranial glioma is paramount for neuro-oncological diagnostics, and it provides images that are helpful for surgery planning and intraoperative guidance during tumor resection, including assessment of the involvement of functionally eloquent brain structures. This study reviews emerging MRI techniques to depict structural information, diffusion characteristics, perfusion alterations, and metabolism changes for advanced neuro-oncological imaging. In addition, it reflects current methods to map brain function close to a tumor, including functional MRI and navigated transcranial magnetic stimulation with derived function-based tractography of subcortical white matter pathways. We conclude that modern preoperative MRI in neuro-oncology offers a multitude of possibilities tailored to clinical needs, and advancements in scanner technology (e. g., parallel imaging for acceleration of acquisitions) make multi-sequence protocols increasingly feasible. Specifically, advanced MRI using a multi-sequence protocol enables noninvasive, image-based tumor grading and phenotyping in patients with glioma. Furthermore, the add-on use of preoperatively acquired MRI data in combination with functional mapping and tractography facilitates risk stratification and helps to avoid perioperative functional decline by providing individual information about the spatial location of functionally eloquent tissue in relation to the tumor mass. KEY POINTS:: · Advanced preoperative MRI allows for image-based tumor grading and phenotyping in glioma.. · Multi-sequence MRI protocols nowadays make it possible to assess various tumor characteristics (incl. perfusion, diffusion, and metabolism).. · Presurgical MRI in glioma is increasingly combined with functional mapping to identify and enclose individual functional areas.. · Advancements in scanner technology (e. g., parallel imaging) facilitate increasing application of dedicated multi-sequence imaging protocols.. CITATION FORMAT: · Sollmann N, Zhang H, Kloth C et al. Modern preoperative imaging and functional mapping in patients with intracranial glioma. Fortschr Röntgenstr 2023; 195: 989 - 1000.

Effectiveness and Safety of CT-Guided Facet Joint Cyst Rupture for Radicular Pain as First Choice Therapy: A Retrospective Analysis.

OBJECTIVE: To evaluate effectiveness and safety of computed tomography (CT)-guided cyst rupture with intraarticular contrast-enhanced injection of steroid and local anesthetic as first choice therapy in patients with facet joint cyst-induced radicular pain. DESIGN: Retrospective data set analysis. SETTING: University hospital. SUBJECTS: One hundred and twenty-one patients suffering from radicular pain attributable to facet joint cysts were included. METHODS: The rate of patients without following surgery was assessed and defined as surrogate to measure effectiveness. Patients' characteristics, procedure-associated complications, technical aspects, and imaging findings on magnetic resonance imaging (MRI) were analyzed. A subgroup of 65 patients (54%) underwent telephone interview to assess pain relief and clinical outcome measured by Numeric Rating Scale and Oswestry Disability Index. Analyses between the groups with and without surgery were performed by Fisher exact test and two-sample unpaired t-test, respectively. RESULTS: The effectiveness of CT-guided cyst rupture was found to be 66.1%. Procedure-induced pain yielded in premature abort in two cases (1.7%). The detection of epidural contrast agent was statistically significantly associated with no need for surgery (P = .010). The cyst level was associated with the status of following surgery (P = .026), that is, cysts at lower lumbar spine were easier to rupture than cysts at other locations (cervical, thoracic, or upper lumbar spine). No further significant association was found. CONCLUSIONS: CT-guided cyst rupture as the first-choice therapy in patients with cyst-induced radicular pain was safe and effective. Successful cyst rupture was associated with no need for surgery. Cysts at lower lumbar spine revealed the highest success rate.

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.

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.