3D CISS Research Articles

Radiologic evaluation of pediatric hydrocephalus

The aim of this review is to present the contemporary role of radiology in evaluating pediatric hydrocephalus. Although conventional brain imaging with ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) reveal the degree of ventricular enlargement and often the etiology of the hydrocephalus, the diagnosis and management of hydrocephalus present common problems in pediatric populations. US, usually sufficient to assess and monitor ventricular size, is used most commonly in preterm infants who have germinal matrix hemorrhages and not able to tolerate transport to the radiology department. Although CT can demonstrate gross dilatation of ventricles, in most cases, it will be necessary to more closely define the nature of the obstruction, either functionally or anatomically. MRI is the best imaging modality to provide such functional and anatomic information. However, since identification of obstructive pathologic processes at any level through the cerebrospinal fluid (CSF) pathway in patients with hydrocephalus is of significant importance because it can change the treatment options, avoiding shunt insertion, a more sophisticated MRI approach is needed instead of obtaining a routine cranial MRI. Furthermore, the outcome after neuroendoscopic procedures is clearly related to patient selection under guidance of neuroimaging. Therefore, the article focuses mainly on the effective usage of various MRI sequences in both diagnosis and follow-up of pediatric hydrocephalus, such as 3D CISS, cine PC, TSE, and GRE T2* sequences, to be able to investigate all possible obstructive pathology through the CSF pathway and to assess the efficiency of treatment in a standardized way.

Combined Electric and Acoustic Stimulation: Successful Treatment Option for Partial Deafness

Combined Electric and Acoustic Stimulation: Successful Treatment Option for Partial Deafness

Estudio por resonancia magnética del contacto neurovascular en el espasmo hemifacial esencial: empleo de secuencia CISS y angiografía por resonancia magnética

Background and purpose The purpose of this article is to assess the validity of the magnetic resonance imaging (MRI) CISS 3D sequence associated with 3D time of flight (TOF) angiographic sequence in order to detect neurovascular contact (NVC) between the facial nerve and neighbouring arteries in patients with essential hemifacial spasm (HFS) and to determine the relationship between HFS symptoms and NVC and NVC image features (type, number and site). Materials and methods We prospectively enrolled 120 cerebellopontine angle (CPA) MRI studies, 44 cases with HFS symptoms and 76 which were asymptomatic (controls), using axial T2-weighted (CISS) and axial 3D TOF series with associated Maximal intensity (MIP) reconstructions. Prior TOF angiographic studies were available for 56 cases without associated CISS images and the results obtained from that study were compared with the results of the current study. Results The diagnostic values obtained significantly favoured the protocol used in this study, which demonstrated a sensitivity of 77.27% and a specificity of 75%. There was a statistically significant relationship between the presence of NVC and HFS symptoms (p < 0,0001). Only one statistically significant relationship was found between facial nerve displacement (in type of NVC) and HFS symptoms (p = 0.019). Conclusions The proposed MRI protocol is sensitive and valid for detecting NVC in patients with HFS. The results of our study support a relationship between NVC and HFS symptoms. It is not a simple relationship, however. It may be influenced by other factors, such as displacement of the facial nerve due to NVC.

New approaches in imaging of the brachial plexus

Imaging plays an essential role for the detection and analysis of pathologic conditions of the brachial plexus. Currently, several new techniques are used in addition to conventional 2D MR sequences to study the brachial plexus: the 3D STIR SPACE sequence, 3D heavily T2w MR myelography sequences (balanced SSFP = CISS 3D, True FISP 3D, bFFE and FIESTA), and the diffusion-weighted (DW) neurography sequence with fiber tracking reconstruction (tractography). The 3D STIR sequence offers complete anatomical coverage of the brachial plexus and the ability to slice through the volume helps to analyze fiber course modification and structure alteration. It allows precise assessment of distortion, compression and interruption of postganglionic nerve fibers thanks to the capability of performing maximum intensity projections (MIP) and multiplanar reconstructions (MPRs). The CISS 3D, b-SSFP sequences allow good visualization of nerve roots within the spinal canal and may be used for MR myelography in traumatic plexus injuries. The DW neurography sequence with tractography is still a work in progress, able to demonstrate nerves tracts, their structure alteration or deformation due to pathologic processes surrounding or located along the postganglionic brachial plexus. It may become a precious tool for the understanding of the underlying molecular pathophysiologic mechanisms in diseases affecting the brachial plexus and may play a role for surgical planning procedures in the near future.

Study of neurovascular contact in essential hemifacial spasm: an example of CISS sequence and magnetic resonance angiography

Background and purpose The purpose of this article is to assess the validity of the magnetic resonance imaging (MRI) CISS 3D sequence associated with 3D time of flight (TOF) angiographic sequence in order to detect neurovascular contact (NVC) between the facial nerve and neighbouring arteries in patients with essential hemifacial spasm (HFS) and to determine the relationship between HFS symptoms and NVC and NVC image features (type, number and site). Materials and methods We prospectively enrolled 120 cerebellopontine angle (CPA) MRI studies, 44 cases with HFS symptoms and 76 which were asymptomatic (controls), using axial T2-weighted (CISS) and axial 3D TOF series with associated Maximal intensity (MIP) reconstructions. Prior TOF angiographic studies were available for 56 cases without associated CISS images and the results obtained from that study were compared with the results of the current study. Results The diagnostic values obtained significantly favoured the protocol used in this study, which demonstrated a sensitivity of 77.27% and a specificity of 75%. There was a statistically significant relationship between the presence of NVC and HFS symptoms (p < 0.0001). Only one statistically significant relationship was found between facial nerve displacement (in type of NVC) and HFS symptoms (p = 0.019). Conclusions The proposed MRI protocol is sensitive and valid for detecting NVC in patients with HFS. The results of our study support a relationship between NVC and HFS symptoms. It is not a simple relationship, however. It may be influenced by other factors, such as displacement of the facial nerve due to NVC.

Vascular compression of the trigeminal nerve is a frequent finding in asymptomatic individuals: 3-T MR imaging of 200 trigeminal nerves using 3D CISS sequences

The aim of this study was to assess whether individuals without symptoms of trigeminal neuralgia exhibit vascular compression of the trigeminal nerve. This was investigated using ultra-high-field MR imaging. One hundred subjects were imaged using a 3-T magnet and high-spatial-resolution three-dimensional (3D) MR imaging with 3D constructive interference in steady-state sequences. Neurovascular compression (NVC) was detected in 92 of the individuals, with 83 cases bilateral and 9 unilateral. In total, 175 (87.5%) of the 200 nerves examined showed NVC. In 58% of the affected individuals, the vessel was compressing a site in the proximal third of the trigeminal nerve. Eighty-six percent of the compressing vessels were arteries, and 14% were veins. Ours is the first study to have evaluated NVC of the trigeminal nerve in asymptomatic individuals using 3-T MR imaging. The high prevalence of compression we observed is close to rates of NVC that have been documented in large series of microvascular decompression for trigeminal neuralgia. Our findings strongly suggest that vascular compression of the trigeminal nerve is not necessarily pathological.

Orbital Cysticercosis: Comparing Multi-Slice CT and Steady State MR to Identify Scolex

Orbital cysticercosis with both ocular and extraocular involvement is common in endemic areas. The presence of scolex is considered diagnostic of cysticercosis. We sought to compare multi-slice CT and 3D steady state MR in the identification of scolex in orbital cysticercosis. Three patients with orbital cysticercosis (two extra-ocular, one ocular) were studied using multi-slice CT with thin coronal and sagittal reformations and 3D steady state MR (CISS 3D - Constructive Interference in Steady State) sequence.

Detection of Root Avulsion in the Dominant C7 Obstetric Brachial Plexus Lesion: Experience with Three-dimensional Constructive Interference in Steady-state Magnetic Resonance Imaging and Electrophysiology

Preoperative, reliable detection by ancillary investigations of spinal nerve root avulsions in infants with severe obstetric brachial plexus lesions to avoid ineffective operative repair from deceivingly intact but actually avulsed nerve roots. Ten infants were selected with an infrequent, severe dominant C7 lesion, primarily because of the anatomically distinct supraclavicular course of this spinal nerve. Three-dimensional constructive interference in steady-state magnetic resonance imaging (3D CISS MRI) studies under mild sedation were performed and evaluated for detection of avulsed nerve roots by two experienced neuroradiologists. Preoperative electrodiagnostics (electromyography and somatosensory evoked potentials) as well as intraoperative somatosensory potentials and muscle contractions after electrostimulation were recorded. Preoperative and intraoperative ancillary investigations were correlated with intraoperative findings in eight patients and clinical status in two children who recovered spontaneously. Despite two minor motion artifacts, the quality of the 3D CISS MRI studies was good. In 8 of 10 patients, prediction of root continuity was consistent with operative or clinical findings, and 2 remained doubtful. Preoperative and intraoperative electrodiagnostics tended not to correlate with intraoperative findings in this small, selected group. 3D CISS MRI provides good images of anterior and posterior spinal roots in infants with obstetric brachial plexus lesions. Images seem to allow accurate prediction of root avulsion in the majority of patients. In this study, electrodiagnostics were of limited value.

Neurovascular relationship at the trigeminal root entry zone in persistent idiopathic facial pain: findings from MRI 3D visualisation

Background: Patients with atypical neuralgia or atypical facial pain have been surgically treated with microvascular decompression (MVD) of the trigeminal root entry zone (TREZ). There are no data regarding the...

The Optic Canal in Basal Meningioma—The Value of CISS 3D Sequences in Preoperative Planning

The Optic Canal in Basal Meningioma—The Value of CISS 3D Sequences in Preoperative Planning

Magnetic resonance imaging study of lumbosacral spinal cord nerves before artificial somatic-central nervous system-autonomic reflex pathway establish ment

目的 探讨MRI在人工体神经-内脏神经反射弧建立术前腰骶部脊神经评估的价值.方法对10例神经源性膀胱患者均采用常规MRI、稳态构成干扰序列(constructive inference in steady state,CISS)成像,并对T2W CISS三维(3D)原始数据进行多平面重组(multiple planar reformation, MPR).结果 MRI发现,脊髓栓系综合征5例,其中1例合并脊髓血管畸形,脊神经返折走行,出硬脊膜处脊神经数目异常;脊髓损伤4例,椎管内占位病变1例,脊神经漂浮下行,神经根数目正常.结论常规MRI及T2W CISS 3D检查对人工体神经-内脏神经反射弧建立术前脊神经的评估具有重要价值.MPR可以清晰的显示脊神经的走行及前后根的排列。

Spontaneous regression of experimental gliomas—An immunohistochemical and MRI study of the C6 glioma spheroid implantation model

Objective: The orthotopic C6 glioma spheroid implantation model has been used to examine factors of neoangiogenesis, growth factor release, and protease expression as well the effect of antitumor agents. The present study systematically investigates the long-term course of orthotopically implanted C6 spheroid gliomas. Methods: Reaggregated C6 spheroid tumors were implanted into the forebrain of 48 male Sprague–Dawley rats (32 immunocompetent, 16 thymectomized). The animals were examined by MRI at postoperative day (POD) 7, 14, 21, 28, 32, 45, 60, and 70. The MRI protocol included a T2-w and T1-w SE sequence before and after application of contrast medium and a CISS 3D sequence for volumetry. A total of six animals were selected after each MR exam from both groups and sacrificed for HE light microscopy and CD8+ T-lymphocyte, ED1+ macrophage, CD31+ endothelial cell immunohistochemistry. Results: The tumors progressed to reach a maximum volume on day 28: 0.23 ± 0.05 ml in the thymectomized and 0.16 ± 0.021 ml in the immunocompetent group. Tumors then consistently regressed to vanish completely by POD 70. The influx of cytotoxic CD8+ T-lymphocytes correlated with tumor progression and the tumors reached a larger size in the thymectomized group. However, the time course of tumor regression was the same for both groups. Conclusion: The present data suggest that the orthotopic C6 glioma implanted into Sprague–Dawley rats will progress within a time span of approximately 4 weeks and can then retrogress again spontaneously. This finding has to be taken into account when deciding on a study protocol and the appropriate animal model. The C6 glioma model may be suitable to study the cell biological steps involved in the phenomenon of spontaneous tumor regression.

The integrated three-dimensional image of SPECT and MRI in malignant glioma

Objective: The orthotopic C6 glioma spheroid implantation model has been used to examine factors of neoangiogenesis, growth factor release, and protease expression as well the effect of antitumor agents. The present study systematically investigates the long-term course of orthotopically implanted C6 spheroid gliomas. Methods: Reaggregated C6 spheroid tumors were implanted into the forebrain of 48 male Sprague–Dawley rats (32 immunocompetent, 16 thymectomized). The animals were examined by MRI at postoperative day (POD) 7, 14, 21, 28, 32, 45, 60, and 70. The MRI protocol included a T2-w and T1-w SE sequence before and after application of contrast medium and a CISS 3D sequence for volumetry. A total of six animals were selected after each MR exam from both groups and sacrificed for HE light microscopy and CD8+ T-lymphocyte, ED1+ macrophage, CD31+ endothelial cell immunohistochemistry. Results: The tumors progressed to reach a maximum volume on day 28: 0.23 ± 0.05 ml in the thymectomized and 0.16 ± 0.021 ml in the immunocompetent group. Tumors then consistently regressed to vanish completely by POD 70. The influx of cytotoxic CD8+ T-lymphocytes correlated with tumor progression and the tumors reached a larger size in the thymectomized group. However, the time course of tumor regression was the same for both groups. Conclusion: The present data suggest that the orthotopic C6 glioma implanted into Sprague–Dawley rats will progress within a time span of approximately 4 weeks and can then retrogress again spontaneously. This finding has to be taken into account when deciding on a study protocol and the appropriate animal model. The C6 glioma model may be suitable to study the cell biological steps involved in the phenomenon of spontaneous tumor regression.

MR Volumetrie des N. trigeminus bei Patienten mit einseitigen Gesichtsschmerzen

Purpose: To assess whether MRI can detect atrophy of the trigeminal nerve in patients with trigeminal neuralgia. Materials and Methods: A prospective MRI study was conducted in 39 patients (trigeminal neuralgia, trigeminal neuropathy, or atypical facial pain) and 25 volunteers. Using a coronal orientation (T1 Flash 3D; T2 CISS 3D), regions of interest were delineated in the cisternal part of the trigeminal nerve along the border of the nerve to calculate the volume of the nerve. The volume of the nerve was compared side-by-side in each patient (t-test, p < 0.05) and the volume difference compared between patients and volunteers. Results: The volume of the compromised trigeminal nerve in patients with trigeminal neuralgia was lower than on the contralateral healthy side, with the difference between healthy and compromised side statistically significant (p<0.05). In all other patients and in all volunteers, no significant difference was found between the volume of the healthy and compromised nerve. The volume difference between the healthy and compromised side in patients with trigeminal neuralgia was significantly higher (p<0.05) than in all other patients and volunteers. Conclusion: Atrophy of the trigeminal nerve caused by a nerve-vessel conflict can be detected by MRI. Only patients with trigeminal neuralgia show this unilateral atrophy. Therefore, it is possible to demonstrate the result of the nerve-vessel conflict and to determine the consequences of such a conflict.

MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences

To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5 T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage.

MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences.

To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5 T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage.

Virtual rendering techniques in otologic imaging

Virtual postprocessing techniques combine the advantages of condensing the large amounts of data provided by high-resolution (HR) cross-sectional imaging modalities with those of three-dimensional (3D) imaging. The techniques and indications for virtual representations in imaging of the middle ear (ME), internal ear (IE), and cerebellopontine angle (CPA) are presented together with practical examples. HR data sets acquired by computed tomography (CT) and magnetic resonance imaging (MRI) in patients with ME, IE, and CPA pathologies were transferred to a workstation via an internal network to generate endo- or extraluminal 3D views by means of the volume rendering technique (VRT). The source data were acquired using scanners and imaging protocols with the highest resolution available at present: a multislice spiral CT (MSCT) with a slice thickness of 0.5 mm and a reconstruction increment of 0.2 mm and a 3D CISS sequence with a slice thickness of 0.5 mm for MRI. Virtual endoscopy was superior to cross-sectional images for assessing ME pathologies like dysplasia, postoperative changes, and destructive bone processes with extensive soft-tissue involvement; fibrous obliterations of the internal ear and labyrinthine dysplasia were depicted with a superior image quality on 3D renderings compared to conventional reconstruction techniques. Virtual endoscopy of the CPA and external acoustic meatus (EAM) was helpful in detecting and visualizing neurovascular conflicts and in assigning small intrameatal tumors to components of the acousticofacial bundle. A common feature of all applications was that the large numbers of source images could be reduced to a few 3D reconstructions for documentation and optimized communication of the findings between the radiologist and otologist. Virtual rendering makes an important contribution towards establishing, presenting, and documenting the findings when certain otologic pathologies have to be assessed. It can be used for routine imaging and allows for more efficient handling of the large amounts of imaging data generated by high-resolution cross-sectional imaging modalities.

Visualization of cranial nerves I-XII: value of 3D CISS and T2-weighted FSE sequences.

The aim of this study was to evaluate the sensitivity of the three-dimensional constructive interference of steady state (3D CISS) sequence (slice thickness 0.7 mm) and that of the T2-weighted fast spin echo (T2-weighted FSE) sequence (slice thickness 3 mm) for the visualization of all cranial nerves in their cisternal course. Twenty healthy volunteers were examined using the T2-weighted FSE and the 3D CISS sequences. Three observers evaluated independently the cranial nerves NI-NXII in their cisternal course. The rates for successful visualization of each nerve for 3D CISS (and for T2-weighted FSE in parentheses) were as follows: NI, NII, NV, NVII, NVIII 40 of 40 (40 of 40), NIII 40 of 40 (18 of 40), NIV 19 of 40 (3 of 40), NVI 39 of 40 (5 of 40), NIX, X, XI 40 of 40 (29 of 40), and NXII 40 of 40 (4 of 40). Most of the cranial nerves can be reliably assessed when using the 3D CISS and the T2-weighted FSE sequences. Increasing the spatial resolution when using the 3D CISS sequence increases the reliability of the identification of the cranial nerves NIII-NXII.

The value of T2(*)-weighted MR images for the diagnosis of acoustic neuromas

The aim of this study was to evaluate high resolution T2(*)-weighted MRI—in our case a 3D CISS sequence—for the diagnosis of acoustic neuromas. Especially to be clarified was if high-resolution T2-weighted sequences can substitute T1-weighted contrast-enhanced sequences, and in which circumstances they can give important additional information when compared with contrast-enhanced T1-weighted sequences. Methods and patients: The MR examinations were performed using a 1.5-Tesla unit with a circularly polarized head coil. All 20 patients (11 females, nine males, aged from 12 to 80 years) with acoustic neuromas underwent preoperative MRI with T2*-weighted 3D CISS (slice thickness, 0.7 mm; acquisition time, 8 min) and pre- and postcontrast T1-weighted 3D MP-RAGE (slice thickness, 0.9 mm; acquisition time, 8 min) sequences. The detectability of acoustic neuromas was evaluated following the consensus of three radiologists using a 3D work station (parameters: tumor presence, extent, nerve attribution). Results: All tumors were detected by both contrast-enhanced 3D MP-RAGE and 3D CISS and the diameters of the lesions were equally well measured. 3D CISS was the best sequence for the attribution of a lesion to a certain nerve. Labyrinthine involvement could be better detected using 3D CISS than contrast-enhanced 3D MP-RAGE. Conclusion: High-resolution T2(*)-weighted MRI is a very sensitive method for tumor screening which can also detect even small meatal and labyrinthine neuromas. In the case of abnormal findings (other pathology or variations, e.g. vascular loops); however, contrast-enhanced T1-weighted MRI is necessary in order to confirm the presence of a tumor with typical enhancement.

Correlation of 3d mri and clinical findings in patients with sensorineural hearing loss and/or vertigo

The aim of the study was to correlate clinical and magnetic resonance imaging (MRI) (3D CISS and MP-RAGE) findings in patients with sensorineural hearing loss (SNHL) and/or vertigo. We found a high correlation of MRI and symptoms (17 out of 18 patients, 13 out of 13, respectively) concerning detectability of tumors and acute labyrinthitis. In the case of labyrinthine fibrosis, the correlation between clinical and MRI findings was lower. In conclusion, high-resolution MRI is very suitable in patients with SNHL or vertigo caused by tumors or acute labyrinthitis.