Search

Purpose: Although CT-guided biopsies of the calvarium, skull base, and orbit are commonly performed, the best approaches, efficacy, and safety of such procedures remain scantly described in the literature. This retrospective review of percutaneous biopsies illustrates several approaches to challenging biopsy targets and provides a review of procedural planning considerations and histopathologic yield. Methods: A retrospective review of CT-guided biopsies of the skull base, calvarium, and orbit between 1/1/2010 and 10/30/2020 was conducted. Patient demographics and procedural factors were recorded, including lesion size and location, biopsy approach, and needle gauge. Outcomes were also noted, including CT dose length product, complications, and histopathologic yield. Results: Sixty-one CT-guided biopsies were included in the final analysis: 34 skull base, 23 calvarial, and 4 orbital lesions. The initial diagnostic yield was 32/34 (94%) for skull base lesions, with one false-negative and one non-diagnostic sample. Twenty-one of twenty-three (91%) biopsies in the calvarium were initially diagnostic, with one false-negative and one non-diagnostic sample. In the orbit, 4/4 biopsies were diagnostic. The total complication rate for the cohort was 4/61 (6.6%). Three complications were reported in skull base procedures (2 immediate and 1 delayed). A single complication was reported in a calvarial biopsy, and no complications were reported in orbital biopsies. Conclusion: Percutaneous CT-guided core needle biopsies can be performed safely and with a high diagnostic yield for lesions in the skull base, calvarium, and orbit. [ABSTRACT FROM AUTHOR]

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented. [ABSTRACT FROM AUTHOR]

Dynamic CT myelography is used to precisely localize fast spinal CSF leaks. The procedure is most commonly performed in the prone position, which successfully localizes most fast ventral leaks. We have recently encountered a small subset of patients in whom prone dynamic CT myelography is unsuccessful in localizing leaks. We sought to determine the added value of lateral decubitus dynamic CT myelography, which is occasionally attempted in our practice, in localizing the leak after failed prone dynamic CT myelography. We retrospectively identified 6 patients who underwent lateral decubitus dynamic CT myelography, which was performed in each case because their prone dynamic CT myelogram was unrevealing. Two neuroradiologists independently reviewed preprocedural spine MRI and all dynamic CT myelograms for each patient. Lateral decubitus positioning allowed for precise leak localization in all 6 patients. Five of six patients were noted to have dorsal and/or lateral epidural fluid collections on spine MRI. One patient had a single prominent diverticulum on spine MRI (larger than 6 mm), whereas the others had no prominent diverticula. Our study suggests that institutions performing dynamic CT myelography to localize fast leaks should consider a lateral decubitus study if performing the study in the prone position is unrevealing. Furthermore, the presence of dorsal and/or lateral epidural fluid collections on spine MRI may suggest that a lateral decubitus study is of higher yield and could be considered initially. [ABSTRACT FROM AUTHOR]

Purpose: Dural tears are a common cause of spontaneous spinal CSF leaks. The majority of such leaks occur ventrally along the thecal sac, typically due to ventral osseous spicules that cause a rent in the dura. A minority of dural leaks are posterolateral in location. These leaks usually do not have an identifiable anatomic cause. We have anecdotally observed cases of posterolateral leaks caused by osseous spicules and sought to describe this phenomenon. Methods: We retrospectively reviewed our imaging database, searching for cases of posterolateral CSF leaks caused by osseous spicules. We identified and included three such patients and reviewed imaging and clinical information from each patient. Results: All three patients had been diagnosed using hyperdynamic CT myelography or conventional CT myelography. Their imaging showed dorsal epidural fluid collections that were related to posterolateral leaks adjacent to dorsal osseous spicules. Conclusion: Dorsal osseous spicules have the potential to cause posterolateral CSF leaks. [ABSTRACT FROM AUTHOR]

Purpose: Intrathecal gadolinium magnetic resonance (MR) myelography can be used to localize various types of spinal cerebrospinal fluid (CSF) leaks; however, its diagnostic yield is not well known. We sought to determine the diagnostic yield of MR myelography in patients with spontaneous intracranial hypotension. Methods: A retrospective review was performed on all patients who had undergone intrathecal gadolinium MR myelography at our institution from 2002 to 2020 for suspected spinal CSF leak. The MR myelography images were reviewed for the presence or absence of a spinal CSF leak site. Images were also evaluated for the presence an extradural fluid collection. Results: A total of 97 patients were included in the final cohort. The average age was 52.6 years; 67.0% were female, 4 patients underwent 2 examinations each, yielding a total of 101 MR myelograms. The source of a spinal CSF leak was localized in 14 patients. The diagnostic yield for CSF leak localization on intrathecal gadolinium MR myelography was 14/101 (13.9%) per GdM examination and 14/97 (14.4%) per patient. Among the subset of patients without extradural fluid collections, the yield was 15.7% per examination. All detected leaks were either CSF-venous fistulas or distal nerve root sleeve tears. Conclusion: Intrathecal gadolinium MR myelography is capable of localizing CSF-venous fistulas and distal nerve root sleeve tears; however, our data show that it has a limited diagnostic yield. We suggest that other modalities may be a better first step before attempting intrathecal gadolinium MR myelography. [ABSTRACT FROM AUTHOR]

Purpose: Peripheral enhancement characteristics on magnetic resonance imaging (MRI), namely the rim and flame signs, are specific for intramedullary spinal cord metastases (ISCM) compared to primary cord masses. The study compared the frequency of a novel finding—the central dot sign—in ISCMs versus primary intramedullary masses. Methods: In this study 45 patients with 64 ISCMs and 64 control patients with 64 primary intramedullary cord masses were investigated and 2 radiologists blinded to lesion type independently evaluated MR images for the presence of a central dot sign: a punctate focus of enhancement in/near the center of an enhancing intramedullary mass. The frequency of this sign in the two patient groups was compared. Results: A total of 63 enhancing ISCMs in 44 patients and 54 enhancing primary cord masses in 54 patients were included. The central dot sign was identified in 6% (4/63) of enhancing ISCMs in 9% (4/44) of patients and in none (0/54) of the enhancing primary cord masses (p = 0.038, per patient). The specificity for diagnosing ISCMs among spinal cord masses was 100%. The central dot sign was present in the axial plane only in two ISCMs and in the axial and sagittal planes in two ISCMs. The two ISCMs harboring the central dot sign also demonstrated both the previously described rim and flame signs, and two also demonstrated the rim sign alone. Conclusion: The central dot sign is not sensitive but highly specific for ISCMs compared to primary spinal cord masses. The rim and/or flame signs may or may not be concurrently present in ISCMs. [ABSTRACT FROM AUTHOR]

Background and Purpose: Radiation therapy is commonly utilized in the majority of solid cancers and many hematologic malignancies and other disorders. While it has an undeniably major role in improving cancer survival, radiation therapy has long been recognized to have various negative effects, ranging from mild to severe. In this manuscript, we review several intracranial manifestations of therapeutic radiation, with particular attention to those that may be encountered by radiologists. Methods: We conducted an extensive literature review of known complications of intracranial radiation therapy. Based on this review, we selected complications that had salient, recognizable imaging findings. We searched our imaging database for illustrative examples of these complications, focusing only on patients who had a history of intracranial radiation therapy. We then selected cases that best exemplified expected imaging findings in these entities. Results: Based on our initial literature search and imaging database review, we selected cases of radiation-induced meningioma, radiation-induced glioma, cavernous malformation, enlarging perivascular spaces, leukoencephalopathy, stroke-like migraine after radiation therapy, Moyamoya syndrome, radiation necrosis, radiation-induced labyrinthitis, optic neuropathy, and retinopathy. Although retinopathy is not typically apparent on imaging, it has been included given its clinical overlap with optic neuropathy. Conclusions: We describe the clinical and imaging features of selected sequelae of intracranial radiation therapy, with a focus on those most relevant to practicing radiologists. Knowledge of these complications and their imaging findings is important, because radiologists play a key role in early detection of these entities. [ABSTRACT FROM AUTHOR]