High-Resolution Head CTA: A Prospective Patient Study Comparing Image Quality of Photon-Counting Detector CT and Energy-Integrating Detector CT.

BACKGROUND AND PURPOSE: Photon-counting detector CT (PCD-CT) is now clinically available and offers ultra-high-resolution (UHR) imaging. Our purpose was to prospectively evaluate the relative image quality and impact on diagnostic confidence of head CTA images acquired by using a PCD-CT compared with an energy-integrating detector CT (EID-CT). MATERIALS AND METHODS: Adult patients undergoing head CTA on EID-CT also underwent a PCD-CT research examination. For both CT examinations, images were reconstructed at 0.6 mm by using a matched standard resolution (SR) kernel. Additionally, PCD-CT images were reconstructed at the thinnest section thickness of 0.2 mm (UHR) with the sharpest kernel, and denoised with a deep convolutional neural network (CNN) algorithm (PCD-UHR-CNN). Two readers (R1, R2) independently evaluated image quality in randomized, blinded fashion in 2 sessions, PCD-SR versus EID-SR and PCD-UHR-CNN versus EID-SR. The readers rated overall image quality (1 [worst] to 5 [best]) and provided a Likert comparison score (-2 [significantly inferior] to 2 [significantly superior]) for the 2 series when compared side-by-side for several image quality features, including visualization of specific arterial segments. Diagnostic confidence (0-100) was rated for PCD versus EID for specific arterial findings, if present. RESULTS: Twenty-eight adult patients were enrolled. The volume CT dose index was similar (EID: 37.1 ± 4.7 mGy; PCD: 36.1 ± 4.0 mGy). Overall image quality for PCD-SR and PCD-UHR-CNN was higher than EID-SR (eg, PCD-UHR-CNN versus EID-SR: 4.0 ± 0.0 versus 3.0 ± 0.0 (R1), 4.9 ± 0.3 versus 3.0 ± 0.0 (R2); all P values < .001). For depiction of arterial segments, PCD-SR was preferred over EID-SR (R1: 1.0-1.3; R2: 1.0-1.8), and PCD-UHR-CNN over EID-SR (R1: 0.9-1.4; R2: 1.9-2.0). Diagnostic confidence of arterial findings for PCD-SR and PCD-UHR-CNN was significantly higher than EID-SR: eg, PCD-UHR-CNN versus EID-SR: 93.0 ± 5.8 versus 78.2 ± 9.3 (R1), 88.6 ± 5.9 versus 70.4 ± 5.0 (R2); all P values < .001. CONCLUSIONS: PCD-CT provides improved image quality for head CTA images compared with EID-CT, both when PCD and EID reconstructions are matched, and to an even greater extent when PCD-UHR reconstruction is combined with a CNN denoising algorithm.

CellKine clinical trial: first report from a phase 1 trial of allogeneic bone marrow-derived mesenchymal stem cells in subjects with painful lumbar facet joint arthropathy.

Background: Lumbar facet joint arthropathy (LFJA) is a major cause of low back pain (LBP), with current treatments offering limited long-term benefits. Bone marrow-derived mesenchymal stem cells (BM-MSCs) show promise due to their immunomodulatory and trophic effects, potentially addressing underlying degenerative processes in LFJA. Objectives: This initial report describes the outcomes of the first treated patient in an ongoing mutidisciplinary phase 1 clinical trial evaluating the safety and feasibility of intra-articular allogeneic BM-MSCs for painful LFJA. Methods: Following enrollment in our IRB-approved protocol, symptomatic LFJA was confirmed through double blocks on L4 and L5 medial branches. Two 1-mL syringes, each containing 10 million BM-MSCs, were prepared in the cGMP facility and administered bilaterally to the patient's L4-L5 lumbar facet joints. The patient underwent standardized follow-ups, including clinical examinations and functional and imaging assessments for 2 years, utilizing patient-reported outcomes measurement information system-computer adaptive tests (PROMIS CATs), visual analogue scale, Oswestry disability index, work functional status and opioid pain medication use, and MR imaging Fenton-Czervionke score. Results: The patient tolerated the procedure well, with no drug-related adverse events during the study period. Pain, spine function, and work functional status improved at multiple follow-ups. This patient also reported improvements in mental and social health, along with a notable improvement in the grade of facet synovitis observed at the one-year follow-up MRI evaluation. Conclusions: This case report suggests the safety and feasibility of administering intra-articular allogeneic BM-MSCs, offering therapeutic benefits for pain management and functional activities.

A Standardized Approach to MRI-Guided Stereotactic Laser Corpus Callosotomy: Technical Description and Pediatric Case Series.

BACKGROUND AND OBJECTIVES: Corpus callosotomy is an effective procedure approach for treating medication-resistant drop seizures, which pose a significant challenge in patients with epilepsy. Laser interstitial thermal therapy offers an alternative to open surgery for performing corpus callosotomy that may limit approach-related comorbidities. Practices vary regarding the number of laser filaments used and staging; outcome data for pediatric patients remain relatively limited. METHODS: We illustrate a set of 4 standardized trajectories for performing MRI-guided stereotactic laser corpus callosotomy (SLCC). For this retrospective cohort study in a pediatric neurosurgery practice, the medical records and imaging were reviewed for 10 consecutive patients who had medication-refractory drop seizures and underwent SLCC. Data collected and analyzed included patient and epilepsy characteristics, procedural details, surgical approaches, and clinical follow-up results. RESULTS: Over 2 years, complete, single-stage SLCC was performed in 8 patients, and posterior completion SLCC was performed in 2 patients who had previously had open anterior corpus callosotomy. Four laser fibers were used in four-eighth complete SLCC, and 3 fibers were used in four-eighth complete SLCC. Seven of 10 patients were discharged from the hospital on postoperative day 1, with only 1 requiring a maximum stay of 6 days. Five of 9 evaluable patients reported no drop seizures at the last clinical follow-up. In the other 4 patients, 1 experienced them only rarely, another experienced less than 25% preoperative frequency, and the remaining 2 had less than a 50% improvement. In addition, improvement in other seizure types exceeded 50% in 8 of 9 patients. Notably, no perioperative or postoperative complications were observed, nor were there any sustained neurological deficits reported. CONCLUSION: Complete SLCC can be safely and effectively performed in pediatric patients. It is comparable in effectiveness with open surgery but has lower complication rates and shorter hospitalization.

Myelographic Techniques for the Localization of CSF-Venous Fistulas: Updates in 2024.

CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. Despite their relatively frequent occurrence, they can be exceedingly difficult to detect on imaging. Since the initial description of CVFs in 2014, the recognition and diagnosis of this type of CSF leak has continually increased. As a result of multi-institutional efforts, a wide spectrum of imaging modalities and specialized techniques for CVF detection is now available. It is important for radiologists to be familiar with the multitude of available techniques, because each has unique advantages and drawbacks. In this article, we review the spectrum of imaging modalities available for the detection of CVFs, explain the advantages and disadvantages of each, provide typical imaging examples, and discuss provocative maneuvers that may improve the conspicuity of CVFs. Discussed modalities include conventional CT myelography, dynamic myelography, digital subtraction myelography, conebeam CT myelography, decubitus CT myelography by using conventional energy-integrating detector scanners, decubitus photon counting CT myelography, and intrathecal gadolinium MR myelography. Additional topics to be discussed include optimal patient positioning, respiratory techniques, and intrathecal pressure augmentation.

Imaging Findings in Giant Cell Arteritis: Don't Turn a Blind Eye to the Obvious!

Giant cell arteritis (GCA) is the most common primary large vessel systemic vasculitis in the Western World. Even though the involvement of scalp and intracranial vessels has received much attention in the neuroradiology literature, GCA, being a systemic vasculitis, can involve multiple other larger vessels including the aorta and its major head and neck branches. Herein, the authors present a pictorial review of the various cranial, extracranial, and orbital manifestations of GCA. An increased awareness of this entity may help with timely and accurate diagnosis, helping expedite therapy and preventing serious complications.

High yield clinical applications for photon counting CT in neurovascular imaging.

Photon-counting CT (PCCT) uses a novel X-ray detection mechanism that confers many advantages over that used in traditional energy integrating CT. As PCCT becomes more available, it is important to thoroughly understand its benefits and highest yield areas for improvements in diagnosis of various diseases. Based on our early experience, we have identified several areas of neurovascular imaging in which PCCT shows promise. Here, we describe the benefits in diagnosing arterial and venous diseases in the head, neck, and spine. Specifically, we focus on applications in head and neck CT angiography (CTA), spinal CT angiography, and CT myelography for detection of CSF-venous fistulas. Each of these applications highlights the technological advantages of PCCT in neurovascular imaging. Further understanding of these applications will not only benefit institutions incorporating PCCT into their practices but will also help guide future directions for implementation of PCCT for diagnosing other pathologies in neuroimaging.

Beyond Anatomy: Fat-Suppressed MR and Molecular Imaging of Spinal Pain Generators.

Spine pain is highly prevalent and costly, but evaluation with clinical features and anatomic imaging remain limited. Fat-suppressed MR imaging and molecular imaging (MI) may help identify inflammatory, lesional, and malignant causes. Numerous MI agents are available, each with advantages and disadvantages. Herein, FDG PET, prostate-specific membrane antigen (PSMA), bone radiotracers, and others are highlighted. No specific pain MI agents have been identified, but mechanisms of key agents are shown in video format, and the mechanism of PSMA as a theranostic agent is displayed. A multidisciplinary approach is needed to master this topic.

MRI-guided focused ultrasound ablation of painful lumbar facet joints: a retrospective assessment of safety and tolerability in human subjects.

OBJECTIVE: To evaluate the safety and tolerability of MRI-guided focused ultrasound (MRgFUS) for the treatment of facet joint-mediated pain in human subjects for whom conventional treatment had failed. Secondarily, to evaluate effectiveness of the procedure. METHODS: Consecutive patients who underwent MRgFUS at our institution were retrospectively identified. Chart review was performed to obtain relevant clinical and technical data. All patients had chronic low back pain and positive comparative medial branch blocks. RESULTS: Twenty-six MRgFUS treatments in 20 patients were included. Mean sonication energy was 1436.6 Joules. The procedure was technically successful in all patients. Of the treated patients, 29.6% experienced short-term worsening of low back pain immediately after the procedure, all by 1-4 points on a 0-10 scale. One patient (3.8%) reported temporary worsening of preexisting radicular symptoms after the procedure. Of 21 treatments with clinical follow-up of at least 3 months available, 12 (57.1%) had >3 months' pain relief, 2 (10%) had <3 months' benefit, 6 (30%) reported no benefit, and 1 (5%) patient was lost to follow-up. In patients who reported at least some benefit with prior conventional radiofrequency ablation, 8/10 (80%) benefited from the MRgFUS procedure. CONCLUSION: The present study demonstrates that MRgFUS ablation of the lumbar facet joints is a safe and tolerable procedure in human subjects and could provide another option for patients for whom radiofrequency ablation had failed. More than half of all patients received significant durable pain relief, which jumped to 80% for patients who had experienced at least some benefit from prior radiofrequency ablations.

Laser Interstitial Thermal Therapy for Epilepsy.

Laser interstitial thermal therapy is an important new technique with a diverse use in epilepsy. This article gives an up-to-date evaluation of the current use of the technique within epilepsy, as well as provides some guidance to novice users appropriate clinical cases for its use.