Localization of spinal CSF leaks may require multiple myelograms when the initially suspected CSF leak type is not identified. We describe a salvage CT myelography (CTM) technique in which the patient is repositioned during the same myelographic session to evaluate for an alternative CSF leak type. Eleven patients underwent salvage CTM at three institutions. When the initially suspected CSF leak was not identified, the patient was repositioned with the lumbar puncture needle remaining in place, and additional small contrast boluses and targeted CT acquisitions were performed. Salvage CTM identified alternative CSF leak types across several diagnostic scenarios involving ventral, lateral, dorsal/dorsolateral, and sacral dural tears and CSF-venous fistulas. The mean procedural time was 55.9 minutes, mean contrast dose was 12.5 cc, and mean dose-length product was 2180 mGy-cm. Salvage CTM is an adaptive, same-session strategy that may reduce the need for repeat myelographic sessions and additional lumbar punctures while maintaining reasonable procedural times and contrast doses.

Spontaneous intracranial hypotension is a frequently debilitating condition that is most commonly caused by loss of cerebrospinal fluid (CSF) from the spine. The most frequently occurring types of spontaneous spinal CSF leaks that cause spontaneous intracranial hypotension are ventral dural tears, lateral dural tears, and CSF venous fistulas, but other leak types are recognized including sacral dural tears or fistulas into vascular malformations. Localization and characterization of spinal CSF leaks with CT myelography facilitates subsequent targeted treatment. A tailored approach based on the suspected leak type as determined at MRI of the spine is necessary to maximize the likelihood of a diagnostic study. The authors focus primarily on advanced CT myelographic techniques for leaks from dural tears and CSF venous fistulas. The importance of optimal patient positioning, typical and atypical appearances of the different leak types, and artifacts that can mimic a CSF leak are considered. ©RSNA, 2026 Supplemental material is available for this article. See the invited commentary by Madhavan in this issue.

Myelographic imaging evaluates the spinal canal, nerve roots, and subarachnoid space using intrathecal contrast with fluoroscopy and computed tomography (CT), or noninvasively with MR-myelography. Although MR imaging has largely replaced conventional myelography owing to its superior soft tissue contrast and noninvasive nature, CT myelography remains essential when MR imaging is contraindicated, limited by artifact, or inconclusive. It is particularly valuable for assessing nerve root compression, spinal stenosis, cerebrospinal fluid leaks, postoperative anatomy, and complex lesions. Myelography helps localize pathology to extradural, intradural extramedullary, or intramedullary compartments, guiding diagnosis and surgical planning.

Caudal regression syndrome (CRS) refers to a spectrum of congenital structural defects of the caudal region. We present a case of caudal regression syndrome with the objective of correlating the symptoms of caudal regression syndrome with the detailed imaging findings. A 05-year-old boy who was admitted to Mymensingh Medical College Hospital in August 2025 , presented with a post-urethroplasty state of hypospadias, complaining of urinary incontinence through the normal meatus and a urethrocutaneous fistula. He had dribbling of urine through hypospadias and deformed feet since birth. He also developed progressive lower limb weakness and walking difficulty at the age of 3 years. On clinical examination bilateral calf and hypothenar muscle wasting, reduced muscle power and tone, absent ankle and diminished knee jerks, diminished bulbocavernosus reflex, intact perianal sensation and anal tone were observed. Right-sided planovalgus (flat foot), left-sided cavus foot deformity, a smaller pelvic girdle with flat buttocks and hard swelling over the lower lumbar region were found. On x-ray lumbosacral spine both view, low-positioned L5 vertebra fused with a rudimentary S1 vertebra on the right with the absence of the rest of the sacral pieces and coccyx, broad spinous process of L5 were seen. Vertical talus, absent navicular bones and adducted forefeet and supinated great toes were seen on x-ray foot both view. RGU and MCU confirmed urethrocutaneous fistula. MRI of whole spine with contrast showed spinal cord and subarachnoid space termination at a slightly upper level with multifocal syrinx and anterior epidural lipoma. MR myelogram revealed short and thickened filum terminale. MR neurography demonstrated altered course of both sided lumbo-sacral plexus. Multifocal syrinx at cervical and dorso-lumbar vertebral levels resulted in lower motor type neuropathy and bladder incontinence. Though the patient had autonomic dysfunction of bladder due to the external urethral sphincter dysfunction, dribbling continued through the normal meatus and the weakest fistula tract evidenced by nil post voidal residue. This patient had no bowel incontinence due to intact inferior rectal nerve, a branch of pudendal nerve supplying the rectum.

Computed tomography (CT) and computed tomography-myelography (CT-myelography) are commonly used to evaluate intervertebral disc herniation in dogs. Qualitative CT and CT-myelography imaging criteria used to differentiate intervertebral disc extrusion (IVDE) from disc protrusion (IVDP) are often influenced by observer experience and subjective interpretation. Therefore, this prospective observational study aimed to assess qualitative imaging features, as well as quantitative morphometric indices, on CT and CT-myelography to provide more objective, measurable parameters for differentiating disc herniation type in 36 dogs with surgically confirmed thoracolumbar intervertebral disc disease. Qualitative characteristics, including extension of herniated material beyond the intervertebral disc space and lateralization of the lesion on both imaging modalities, were more frequently associated with IVDE. In contrast, midline disc herniation on both imaging modalities and degenerative bridging spondyloarthropathy on CT were more commonly observed in IVDP. The ratio of the maximum cross-sectional area of the herniated disc material to the area of the vertebral canal at the same level (area index) demonstrated moderate discriminatory ability on both imaging modalities, with high sensitivity, moderate accuracy, but lower specificity, especially on CT, reducing its reliability as a standalone classifier. The ratio of the total volume of herniated material to the total canal volume at the corresponding vertebral level (volume index) demonstrated excellent discriminatory ability with high sensitivity, specificity, and accuracy on both CT and CT-myelography. Overall, the V-index showed the highest diagnostic performance for differentiating disc herniation types, whereas the A-index was limited by lower specificity, with qualitative imaging features providing complementary information.