Fluoroscopy- and CT-Guided Gold Fiducial Marker Placement for Intraoperative Localization during Spinal Surgery: Review of 179 Cases at a Single Institution-Technique and Safety Profile.

BACKGROUND AND PURPOSE: Wrong-level spinal surgery, especially in the thoracic spine, remains a challenge for a variety of reasons related to visualization, such as osteopenia, large body habitus, severe kyphosis, radiographic misinterpretation, or anatomic variation. Preoperative fiducial marker placement performed in a dedicated imaging suite has been proposed to facilitate identification of thoracic spine vertebral levels. In this current study, we report our experience using image-guided percutaneous gold fiducial marker placement to enhance the accuracy and safety of thoracic spinal surgical procedures. MATERIALS AND METHODS: A retrospective review was performed of all fluoroscopy- or CT-guided gold fiducial markers placed at our institution between January 3, 2019, and March 16, 2022. A chart review of 179 patients was performed detailing the procedural approach and clinical information. In addition, the method of gold fiducial marker placement (fluoroscopy/CT), procedure duration, spinal level of the gold fiducial marker, radiation dose, fluoroscopy time, surgery date, and complications (including whether wrong-level surgery occurred) were recorded. RESULTS: A total of 179 patients (104 female) underwent gold fiducial marker placement. The mean age was 57 years (range, 12-96 years). Fiducial marker placement was performed by 13 different neuroradiologists. All placements were technically successful without complications. All 179 (100%) operations were performed at the correct level. Most fiducial markers (143) were placed with fluoroscopy with the most common location at T6-T8. The most common location for placement in CT was at T3 and T4. CONCLUSIONS: All operations guided with gold fiducial markers were performed at the correct level. There were no complications of fiducial marker placement.

Temporal Characteristics of CSF-Venous Fistulas on Digital Subtraction Myelography.

BACKGROUND AND PURPOSE: CSF-venous fistula can be diagnosed with multiple myelographic techniques; however, no prior work has characterized the time to contrast opacification and the duration of visualization. The purpose of our study was to evaluate the temporal characteristics of CSF-venous fistula on digital subtraction myelography. MATERIALS AND METHODS: We reviewed the digital subtraction myelography images of 26 patients with CSF-venous fistulas. We evaluated how long the CSF-venous fistula took to opacify after contrast reached the spinal level of interest and how long it remained opacified. Patient demographics, CSF-venous fistula treatment, brain MR imaging findings, CSF-venous fistula spinal level, and CSF-venous fistula laterality were recorded. RESULTS: Eight of the 26 CSF-venous fistulas were seen on both the upper- and lower-FOV digital subtraction myelography, for a total of 34 CSF-venous fistula views evaluated on digital subtraction myelography. The mean time to appearance was 9.1 seconds (range, 0-30 seconds). Twenty-two (84.6%) of the CSF-venous fistulas were on the right. The highest fistula level was C7, while the lowest was T13 (13 rib-bearing vertebral bodies). The most common CSF-venous fistula levels were T6 (4 patients) followed by T8, T10, and T11 (3 patients each). The mean age was 58.3 years (range, 31.7-87.6 years). Sixteen patients were women (61.5%). CONCLUSIONS: This is the first study to report the temporal characteristics of CSF-venous fistulas using digital subtraction myelography. We found that on average, the CSF-venous fistula appeared 9.1 seconds (range, 0-30 seconds) after intrathecal contrast reached the spinal level.

Conebeam CT as an Adjunct to Digital Subtraction Myelography for Detection of CSF-Venous Fistulas.

Lateral decubitus digital subtraction myelography is an effective technique for precisely localizing CSF-venous fistulas, a common cause of spontaneous intracranial hypotension. However, despite an optimal imaging technique, digital subtraction myelography fails to identify some CSF-venous fistulas for a variety of reasons. Here, we describe a technique involving conebeam CT performed during intrathecal contrast injection as an adjunct to digital subtraction myelography, allowing identification of some otherwise-missed CSF-venous fistulas.

Sacral CSF-Venous Fistulas and Potential Imaging Techniques.

This is the first study to describe CSF-venous fistulas involving the sacrum, a location that may be underrecognized on the basis of current imaging techniques. We describe a delayed decubitus flat CT myelogram technique that may be useful to identify sacral CSF-venous fistulas.

Percutaneous CT-Guided Core Needle Biopsies of Head and Neck Masses: Review of 184 Cases at a Single Academic Institution, Common and Special Techniques, Diagnostic Yield, and Safety.

BACKGROUND AND PURPOSE: Percutaneous CT-guided core needle biopsies of head and neck lesions can be safely performed with vigilant planning. This largest-to-date single-center retrospective study evaluates multiple approaches with consideration of special techniques and examines the histopathologic yield. MATERIALS AND METHODS: Retrospective review of CT-guided core biopsies of head and neck lesions from January 1, 2010, to October 30, 2020, was performed. We recorded the following: patient demographics, sedation details, biopsy needle type and size, lesion location and size, approach, patient positioning, preprocedural intravenous contrast, proceduralists' years of experience, complications, and pathology results. RESULTS: One hundred eighty-four CT-guided core biopsies were evaluated. The initial diagnostic yield was 93% (171/184). However, of 43/184 (23%) originally "negative for malignancy" biopsies, 4 were eventually positive for malignancy via rebiopsy/excision, resulting in a 2% false-negative rate and an adjusted total diagnostic yield of 167/184 (91%). Biopsies were performed by 16 neuroradiologists with variable experience. The diagnostic yield was essentially the same: 91% (64/70) for proceduralists with ≤3 years' experience, and 90% (103/114) with >3 years' experience. The diagnostic yield was 93% (155/166) for lesions of >10 mm. The diagnostic yield per biopsy needle gauge was the following: 20 ga, 81% (13/16); 18 ga, 93% (70/75); 16 ga, 90% (64/71); and 14 ga, 91% (20/22). There were 4 asymptomatic hematomas, with none requiring intervention. CONCLUSIONS: Percutaneous CT-guided core needle biopsies are safe procedures for superficial and deep head and neck lesions with a high diagnostic yield. Careful planning and special techniques may increase the number of lesions accessible percutaneously while minimizing the risk of complications.

Prevalence of Cervical Artery Abnormalities on CTA in Patients with Spontaneous Coronary Artery Dissection: Fibromuscular Dysplasia, Dissection, Aneurysm, and Tortuosity.

BACKGROUND AND PURPOSE: Little is known about associations between spontaneous coronary artery dissection and cervical artery abnormalities. This study sought to assess the prevalence of cervical artery abnormalities among patients with spontaneous coronary artery dissection. MATERIALS AND METHODS: A retrospective analysis was completed of patients who underwent CTA neck imaging as part of arterial assessment following the diagnosis of spontaneous coronary artery dissection. The internal carotid and vertebral arteries were evaluated for the presence of fibromuscular dysplasia, dissection and/or pseudoaneurysm, ectasia and/or aneurysmal dilation, atherosclerosis, and webs. Carotid tortuosity was categorized into kinks, loops, coils, and retrojugular and/or retropharyngeal carotid courses; vertebral tortuosity was classified by subjective analysis of severity. RESULTS: Two hundred fourteen patients were included in the final cohort, of whom 205 (95.8%) were women; the average age was 54.4 years. Fibromuscular dysplasia was the most frequently observed abnormality (83 patients; 38.8%), followed by dissections and/or pseudoaneurysms (n = 28; 13.1%), ectasia and/or aneurysmal dilation (n = 22; 10.3%), and carotid webs (n = 10; 4.7%). At least 1 type of carotid tortuosity was present in 99 patients (46.3%). The majority (n = 185; 86.4%) of patients had no carotid atherosclerosis; and 26 (12.2%) had mild; 3 (1.4%), moderate; and 0, severe carotid atherosclerosis. CONCLUSIONS: The most common abnormality in the cervical artery vasculature of patients with spontaneous coronary artery dissection is fibromuscular dysplasia. Cervical dissections were higher than previously reported but were not observed in most patients.

Time to Resolution of Inadvertent Subdural Contrast Injection during a Myelogram: When Can the Study Be Reattempted?

BACKGROUND AND PURPOSE: Inadvertent subdural contrast injections can occur during any myelogram. Currently, there are no guidelines defining when residual subdural iodinated contrast will be cleared and no longer interfere with subsequent procedure and imaging. We investigated the time to resolution of subdural contrast using a 2-day lateral decubitus digital subtraction myelogram and associated CT myelogram data in patients undergoing evaluation for spontaneous intracranial hypotension. MATERIALS AND METHODS: Retrospective review of 63 patients with lateral decubitus digital subtraction myelograms from September 4, 2018, to October 1, 2019, was performed. Patients with 2-day lateral decubitus digital subtraction myelograms on 2 consecutive days, with or without a same-day CT myelogram on day 1 and with a same-day CT myelogram on day 2, were included. Patients with next-day CT covering at least the abdomen and pelvis after either-day injection were also included. In cases of subdural injection, next-day CT scans were evaluated for residual subdural contrast. RESULTS: Of 49 included patients, 5 had subdural injection on day 1, with the second-day CT myelogram available for review. One of these 5 patients had subdural injections on 2 different days and subsequently had chest/abdomen/pelvis CTA a day after the second subdural injection. In all 6 cases of subdural injections, there was complete resolution of subdural contrast on the next-day CT, with the shortest time to resolution of approximately 20.5 hours (range, 20.5-28.5 hours). CONCLUSIONS: Our study suggests that resolution of inadvertently injected subdural contrast occurs within 1 day, and the myelogram can be reattempted as early as the next day.

Lateral Decubitus Digital Subtraction Myelography: Tips, Tricks, and Pitfalls.

Digital subtraction myelography is a valuable diagnostic technique to detect the exact location of CSF leaks in the spine to facilitate appropriate diagnosis and treatment of spontaneous spinal CSF leaks. Digital subtraction myelography is an excellent diagnostic tool for assessment of various types of CSF leaks, and lateral decubitus digital subtraction myelography is increasingly being used to diagnose CSF-venous fistulas. Lateral decubitus digital subtraction myelography differs from typical CT and fluoroscopy-guided myelograms in many ways, including equipment, supplies, and injection and image-acquisition techniques. Operators should be familiar with techniques, common pitfalls, and artifacts to improve diagnostic yield and prevent nondiagnostic examinations.

Renal Contrast on CT Myelography: Diagnostic Value in Patients with Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: The significance of renal contrast on CT myelography is uncertain. This project examined different patient populations undergoing CT myelography for the presence of renal contrast to determine whether this finding is of diagnostic value in spontaneous intracranial hypotension. MATERIALS AND METHODS: Four groups of patients were analyzed for renal contrast on CT myelography. The control group underwent CT myelography for reasons other than spontaneous intracranial hypotension (n = 47). Patients in study group 1 had spontaneous intracranial hypotension but CT myelography negative for dural CSF leak and CSF venous fistula (n = 83). Patients in study group 2 had spontaneous intracranial hypotension and CT myelography positive for dural CSF leak (n = 44). Patients in study group 3 had spontaneous intracranial hypotension and CT myelography suggestive of CSF venous fistula due to a hyperdense paraspinal vein (n = 17, eleven surgically confirmed). RESULTS: Renal contrast was present on the initial CT myelography in 0/47 patients in the control group, 10/83 patients in group one, 1/44 patients in group 2, and 7/17 patients in group 3. Renal contrast on initial CT myelography in patients with suspected or surgically confirmed CSF venous fistula was significantly more likely than in patients with a dural CSF leak (P = .0003). CONCLUSIONS: Renal contrast on initial CT myelography was seen only in patients with spontaneous intracranial hypotension. This was more common in confirmed/suspected CSF venous fistulas compared with dural leaks. Early renal contrast in patients with spontaneous intracranial hypotension should prompt scrutiny for a hyperdense paraspinal vein, and, if none is found, potentially advanced diagnostic studies.

Predicting High-Flow Spinal CSF Leaks in Spontaneous Intracranial Hypotension Using a Spinal MRI-Based Algorithm: Have Repeat CT Myelograms Been Reduced?

BACKGROUND AND PURPOSE: We adopted an imaging algorithm in 2011 in which extradural fluid on spinal MR imaging directs dynamic CT myelography. We assessed algorithm compliance and its effectiveness in reducing repeat or unnecessary dynamic CT myelograms. MATERIALS AND METHODS: CT myelograms for CSF leaks from January 2011 to September 2014 were reviewed. Patients with iatrogenic leaks, traumatic brachial plexus injuries, or prior CT myelography within 2 years were excluded. Completion and results of spinal MR imaging, CT myelographic technique, and the need for repeat CT myelography or unnecessary dynamic CT myelograms were recorded. RESULTS: The algorithm was followed in 102 (79%) of 129 patients. No extradural fluid was detected in 75 (74%), of whom 70 (93%) had no leak, 4 (5%) had a slow leak, and 1 (1%) had a fast leak. Extradural fluid was detected in 27 (26%): 24 (89%) fast leaks, 1 (4%) slow leak, and 2 (7%) with no leaks. When the algorithm was followed, 1 (1%) required repeat CT myelography and 3 (3%) had unnecessary dynamic CT myelograms. The algorithm was breached in 27 (21%) cases, including no pre-CT myelogram MR imaging in 11 (41%), performing conventional CT myelography when extradural fluid was present in 13 (48%), and performing dynamic CT myelography when extradural fluid was absent in 3 (11%). Algorithm breaches resulted in 4 (15%) repeat CT myelograms and 3 (12%) unnecessary dynamic CT myelograms, both higher than with algorithm compliance. CONCLUSIONS: Using spinal MR imaging to direct CT myelography resulted in significant reduction in repeat CT myelograms to localize fast leaks with minimal unnecessary dynamic CT myelograms.

The posterior ligamentous complex inflammatory syndrome: spread of fluid and inflammation in the retrodural space of Okada.

The retrodural space of Okada is situated dorsal to the ligamentum flavum in the interlaminar space, and provides communication between contralateral facet joints. MRI will often demonstrate heterogeneous signal abnormality with contrast enhancement in this space and several communicating compartments of the posterior ligamentous complex: bilateral facet joints, adventitial interspinous bursae, or retrodural cysts penetrating the ligamentum flavum. Pars interarticularis defects are frequently present. This imaging pattern may be associated with axial low back pain and/or radicular pain. Recognition of this pattern at MRI has distinct implications for image interpretation, unifying prior reports of involvement of individual components of the posterior ligamentous complex. Its recognition will also affect planning for therapeutic interventional pain procedures. We refer to this constellation of imaging and clinical findings as posterior ligamentous complex inflammatory syndrome (PLCIS).