Normalized signal intensity (SI) obtained from magnetic resonance imaging (MRI) has been used to track anterior cruciate ligament (ACL) postoperative remodeling. We aimed to assess the effect of MRI sequence (PD: proton density-weighted; T2: T2-weighted; CISS: constructive interference in steady state) on postoperative changes in healing ACLs/grafts. We hypothesized that CISS is better at detecting longitudinal SI and texture changes of the healing ACL/graft compared to the common clinical sequences (PD and T2). MR images of patients who underwent ACL surgery were evaluated and separated into groups based on surgical procedure (Bridge-Enhanced ACL Repair (BEAR; n = 50) versus ACL reconstruction (ACLR; n = 24)). CISS images showed decreasing SI across all timepoints in both the BEAR and ACLR groups (p < 0.01), PD and T2 images showed decreasing SI in the 6-to-12- and 12-to-24-month postoperative timeframes in the BEAR group (p < 0.02), and PD images additionally showed decreasing SI between 6- and 24-months postoperation in the ACLR group (p = 0.02). CISS images showed texture changes in both the BEAR and ACLR groups, showing increases in energy and decreases in entropy in the 6-to-12- and 6-to-24-month postoperative timeframes in the BEAR group (p  < $\\lt $  0.04), and increases in energy, decreases in entropy, and increases in homogeneity between 6 and 24 months postoperation in the ACLR group (p < 0.04). PD images showed increases in energy and decreases in entropy between 6- and 24-months postoperation in the ACLR group (p < 0.008). Finally, CISS was estimated to require a smaller sample size than PD and T2 to detect SI differences related to postoperative remodeling.

We report a rare case of idiopathic spinal cord herniation (ISCH) with a history of cerebrospinal fluid (CSF) leakage. ISCH is a protrusion of the spinal cord through a dural defect. Thin constructive interference in steady-state (CISS) images clearly demonstrated the herniated cord in the present case. The myelopathy worsened and the patient underwent surgery for reduction of herniated spinal cord; the dural defect was filled by placing collagen matrix graft (DuraGen®) between the inner and outer dural layers. The patient\'s symptoms have improved without relapse for 8 months since surgery. This method may be a good surgical option for cases of spinal cord herniation.

The aim of this study is to evaluate signal alteration in the inner ear using three-dimensional (3D)-constructive interference in steady state (CISS) sequence in patients with Ménière\'s disease and labyrinthitis and its correlation with clinical and audiological parameters.
The medical records of the department of otorhinolaryngology were searched for patients with Ménière\'s disease or labyrinthitis who underwent MRI with 3D-CISS sequence. Blinded analysis of these patients and of MRI from control subjects without middle or inner ear symptoms was performed to detect any signal asymmetry of the inner ear structures. The results were correlated with clinical symptoms and results of audiological and vestibular tests.
Fifty-eight patients with definite Ménière\'s disease and 5 patients with labyrinthitis as well as 41 control exams were included. A separate analysis was performed for patients with probable Ménière\'s disease (n = 68). A total of 172 3D-CISS sequences were analyzed by 2 blinded independent neuroradiologists. A CISS-hypointense signal of the inner ear structures was found in 3 patients with definite Ménière\'s disease (5.2%), in 4 patients with probable Ménière\'s disease (5.9%), and 2 patients with labyrinthitis (40%). No CISS hypointensity was found in the control group. Although no significant difference in symptoms or audiological test results was found between patients with and without this signal change, the side of hypointensity was frequently correlated with the symptomatic side and with hearing impairment.
CISS hypointensity of the inner ear structures was evident in patients with clinical conditions other than vestibular schwannoma - more frequently in labyrinthitis than in Ménière\'s disease. This signal alteration was frequently encountered on the same symptomatic side as that of the pathological audiology tests, but it is not a predictor for hearing or vestibular impairment.

UNASSIGNED: Due to surgical advancements, the accurate detection of perineural disease spread has become increasingly important in the management and prognostication of head and neck cancers, though MR evaluation has thus far been limited by technical and logistic challenges. The purpose of this study was to specifically evaluate the relative capability of 3D CISS and 3D T2-SPACE imaging to delineate the proximal intracranial divisions of the normal trigeminal nerve, an area important in determining the resectability of intracranial perineural disease.
METHODS: A single center HIPAA-compliant, IRB approved retrospective review of 40 patients with clinical temporal bone/internal auditory canal MR imaging was conducted. 20 patients with 3D CISS images and 20 patients with 3D T2-SPACE images met inclusion criteria. Two radiologists scored the sequences on a 3-point scale based on ability to visualize anatomic structures surrounding the trigeminal nerve in Meckel\'s cave, intracranial trigeminal divisions, skull base neuroforamina, and proximal extracranial mandibular division.
RESULTS: The following anatomic locations scored significantly better in the T2-SPACE sequence compared to the CISS sequence for both raters: intracranial V3 (p < .05), foramen ovale (p < .05), and extracranial V3 (p < .01). The average scores for the anterior Meckel\'s cave and foramen rotundum were higher for the T2-SPACE sequence, although not significantly. Percent interobserver agreement ranged from 50 to 90% and 65-100% for the different anatomic locations on the CISS and T2-SPACE sequences, respectively.
CONCLUSIONS: 3D T2-SPACE was found to be superior to 3D CISS in the evaluation of the distal intracranial and extracranial portions of the normal trigeminal nerve.

Preoperatively determining the extent of parasellar invasion of pituitary macroadenomas is useful for surgical planning and patient counseling. Here, the authors compared constructive interference in steady state (CISS), a T2-weighted gradient-echo MRI sequence, to volume-interpolated breath-hold examination (VIBE), a T1-weighted gradient-echo MRI sequence, for evaluation of cavernous sinus invasion (CSI) by pituitary macroadenomas.
VIBE and CISS images of 98 patients with pituitary macroadenoma were retrospectively analyzed and graded using the modified Knosp classification. The Knosp grades were correlated to surgical findings of CSI, which were determined intraoperatively using 0° and 30° endoscopes. The predictive accuracies for CSI according to the Knosp grades derived from the CISS and VIBE images were compared using receiver operating characteristic (ROC) curves. Postoperative MRI was used to evaluate the gross-total resection (GTR) rates.
The CSI rate by pituitary macroadenomas was 27.6% (27 of 98 cases). Of 196 assessments (left and right sides of 98 macroadenomas), 45 (23.0%) had different Knosp grades when scored using VIBE versus CISS images. For the VIBE images, 0% of Knosp grade 0, 4.5% of grade 1, 23.8% of grade 2, 42.1% of grade 3A, 100% of grade 3B, and 83.3% of grade 4 macroadenomas were found to have CSI intraoperatively. For the CISS images, 0% of Knosp grade 0, 2.1% of grade 1, 31.3% of grade 2, 56.3% of grade 3A, 100% of grade 3B, and 100% of grade 4 macroadenomas were found to have CSI intraoperatively. Two pituitary macroadenomas were classified as grade 4 on VIBE sequences but grades 3A and 2 on CISS sequences; CSI was not observed intraoperatively in both cases. The GTR rate was 64.3% and 60.0% for high-grade (3A, 3B, and 4) macroadenomas classified using VIBE and CISS sequences, respectively. The areas under the ROC curves were 0.94 and 0.97 for VIBE- and CISS-derived Knosp grades (p = 0.007), respectively.
Knosp grades determined using CISS sequence images are better correlated with intraoperative CSI than those determined using VIBE sequence images. CISS sequences may be valuable for the preoperative assessment of pituitary macroadenomas.

BACKGROUND: We investigated the additive value of the 3T 3D constructive interference in steady state (CISS) sequence to conventional MRI for the evaluation of spinal dural arteriovenous fistulae (SDAVF).
METHODS: We included 16 consecutive patients (15 men, 1 woman; age range 42-81 years; mean 64 years) with SDAVF who underwent 3T MRI and digital subtraction angiography (DSA) before treatment. Two neuroradiologists independently evaluated the presence of abnormal vessels on 3D CISS-, T2- and T1-weighted images (T1WI, T2WI), and contrast-enhanced T1WI using a 3-point grading system. Interobserver agreement was assessed by calculating the κ coefficient.
RESULTS: The SDAVF site was the cervical region in one patient, the thoracic region in 12 patients, the lumbar region in two, and the sacral region in one. For the visualization of abnormal vessels, the mean score was significantly higher for 3D CISS than the other sequences (P < 0.05). In 12 of 16 cases (75%) both readers made definite positive findings on additional 3D-CISS images. Interobserver agreement was excellent for 3D CISS images (κ = 1.0), good for T1WI (κ = 0.78; 95% confidence interval [CI] 0.54-1.00) and T2WI (κ = 0.74; 95% CI 0.48-1.00) and moderate for contrast-enhanced T1WI (CET1WI) (κ = 0.50; 95% CI 0.21-0.80).
CONCLUSIONS: For the assessment of abnormal vessels of SDAVF, the 3T 3D CISS sequence adds value to conventional MRI.

BACKGROUND: Lipomyelomeningocele (LMMC) is defined by a low-lying tethered spinal cord protruding posteriorly from the spinal canal and terminating in a lipomatous mass in the subcutaneous meningeal sac. The coexistence of LMMC with split cord malformation (SCM) is rare.
METHODS: We report on a patient with laterally protruded LMMC arising from the hemicord of SCM type I. Direct coronal and axial views (instead of sagittal views) of 3D heavily T2-weighted MR imaging (3D-hT2WI) clearly demonstrated the topographical relationship between both of the hemicords, the bony septum, and nerve roots in the right subcutaneous meningeal sac.
CONCLUSIONS: Combined use of axial and coronal images of 3D-hT2W is useful for visualization and surgery of such a complicated anomaly.

BACKGROUND: Symptomatic extensive spinal extradural meningeal cyst (SEMC) developing after traumatic brachial plexus injury (TBPI) is rare. We discuss the mechanism of extensive SEMC development, surgical strategies, and preventive measures against SEMC after TBPI.
METHODS: A 58-year-old man with TBPI 16 years previously developed spastic paraparesis of the lower limbs, sensory disturbance below the periumbilical level, and dysfunction of bladder and bowel over 2 years. The patient couldn\'t walk and was wheelchair bound. Magnetic resonance imaging (MRI) revealed an extensive multilocular extradural cyst posterior to the spinal cord ranging from the C4 to Th6 level, associated with severe spinal cord compression. On constructive interference in steady-state MRI, the cyst was divided, with many septa, and extended to the root sleeves. During the operation, transdural communication sites of cerebrospinal fluid (CSF) into the cyst were revealed at C5/6, C6/7, and C7/Th1 levels around the nerve root sleeves. Treatment involved unroofing of the cyst wall and closure of the transdural CSF communication without cyst removal. Autologous muscle pieces were placed over the defect to close the transdural communication. Two weeks postoperatively, MRI showed decreased cyst size and reduced spinal cord compression, and the patient could walk without support. It was thought that the patient\'s daily lifting of heavy weights at work and an excessive exercise regimen increased CSF pressure and cyst size after TBPI.
CONCLUSIONS: For patients with TBPI, it is necessary to prevent greater CSF pressure and to perform long-term follow-up MRI after injury.