Three-dimensional Constructive Interference Research Articles

Three-Dimensional Constructive Interference in Steady State Sequences and Phase-Contrast Magnetic Resonance Imaging of Arrested Hydrocephalus

To evaluate the role of three-dimensional constructive interference in steady state (3D-CISS) sequences and phase-contrast magnetic resonance imaging (PC-MRI) in patients with arrested hydrocephalus. A prospective study of 20 patients with arrested hydrocephalus was carried out. All patients underwent PC-MRI and 3D-CISS for assessment of the aqueduct. Axial (through-plane), sagittal (in-plane) PC-MRI, and sagittal 3D-CISS were applied to assess the cerebral aqueduct and the spontaneous third ventriculostomy if present. Aqueductal patency was graded using 3D-CISS and PC-MRI. Quantitative analysis of flow through the aqueduct was performed using PC-MRI. The causes of obstruction were aqueductal obstruction in 75% (n= 15), third ventricular obstruction in 5% (n= 1), and fourth ventricular obstruction in 20% (n= 4). The cause of arrest of hydrocephalus was spontaneous third ventriculostomy in 65% (n= 13), endoscopic third ventriculostomy in 10% (n= 2), and ventriculoperitoneal shunt in 5% (n= 1), and no cause could be detected in 20% of patients (n= 4). There is a positive correlation (r= 0.80) and moderate agreement (κ= 0.509) of grading with PC-MRI and 3D-CISS sequences. The mean peak systolic velocity of cerebrospinal fluid was 1.86 ± 2.48 cm/second, the stroke volume was 6.43 ± 13.81 μL/cycle, and the mean flow was 0.21 ± 0.32 mL/minute. We concluded that 3D-CISS and PC-MRI are noninvasive sequences for diagnosis of the level and cause of arrested hydrocephalus.

Is Quasi-moyamoya Disease a Uniform Disease Entity? A Three-Dimensional Constructive Interference in Steady State Imaging Study

Quasi-moyamoya disease (MMD) or moyamoya syndrome is based on various underlying diseases and radiologically simulates MMD, but its disease entity is still unclear. Recent studies have proven specific shrinkage of the involved arteries in MMD. Using 3-dimensional constructive interference in steady state (3D-CISS), therefore, this study aimed to analyze the outer diameter of the involved arteries in quasi-MMD. This study included 9 patients with quasi-MMD (unilateral type, n = 2; bilateral type, n = 7). Using 3D-CISS, the outer diameter was quantified in the internal carotid artery distal to the posterior communicating artery (C1), the horizontal portion of the middle and anterior cerebral arteries (M1 and A1, respectively), and the basilar artery. Control values were obtained from 17 healthy subjects. In 7 of 9 patients, the outer diameters of C1, M1, and A1 were significantly smaller than those of the controls. On the other hand, the values were normal in other 2 patients. There was no significant difference in the underlying disorders between the 2 groups. All 3 pediatric patients are categorized into the arterial shrinkage group, but 2 of 6 adult patients were not. These findings strongly suggest that quasi-MMD is not a uniform disease entity and includes at least 2 pathophysiologically different groups: the arterial shrinkage group and the nonarterial shrinkage group. A certain subgroup of MMD patients may be misdiagnosed as quasi-MMD because of the patients' comorbid disorders and mixed up with the patients who present angiographic findings similar to MMD in spite of the lack of arterial shrinkage.

Three-dimensional constructive interference in steady-state magnetic resonance imaging diagnosis of isolated unilateral facial nerve hypoplasia.

Three-dimensional constructive interference in steady-state magnetic resonance imaging diagnosis of isolated unilateral facial nerve hypoplasia.

MRI 3D C ISS – A Novel Imaging Modality in Diagnosing Trigeminal Neuralgia – A Review

Trigeminal Neuralgia (TN) is considered as one of the most painful neurologic disorders affecting oro-facial region. TN is often diagnosed clinically based on the patients complete history of pain (severity, duration, episodes etc), relief of pain on test dose of Carbamazepine, regional block of long acting anaesthetic. However, Magnetic Resonance Imaging (MRI) plays an important and confirmatory role in showing Neuro Vascular Conflict (NVC) which is the commonest causative factor for TN. This article reviews the effectiveness of three-dimensional constructive interference in steady-state (3D-CISS) MRI in diagnosing the exact location, degree of neurovascular conflict responsible for classical as well as atypical TN and possible pre-treatment evaluation and treatment outcome.

Specific Shrinkage of Carotid Forks in Moyamoya Disease: A Novel Key Finding for Diagnosis.

This study was aimed to analyze the outer diameter of the involved arteries in moyamoya disease, using three-dimensional (3D) constructive interference in steady state (CISS) and direct surgical inspection. Radiological evaluation was performed in 64 patients with moyamoya disease. As the controls, six patients with severe middle cerebral artery (MCA) stenosis and 17 healthy subjects were also recruited. On 3D-CISS, the outer diameter was quantified in the supraclinoid portion of internal carotid artery (C1), the horizontal portions of MCA (M1) and anterior cerebral artery (A1), and basilar artery. The involved carotid fork was directly observed during surgery in another series of three adult patients with moyamoya disease. In 53 adult patients with moyamoya disease, the outer diameters of C1, M1, and A1 segments were 2.3 ± 0.7 mm, 1.3 ± 0.5 mm, and 1.0 ± 0.4 mm in the involved side (n = 91), being significantly smaller than the control (n = 17), severe M1 stenosis (n = 6), and non-involved side in moyamoya disease (n = 15, P < 0.01). There were significant correlations between Suzuki’s angiographical stage and the outer diameters of C1, M1, and A1 (P < 0.001). The laterality ratio of C1 and M1 was significantly smaller in unilateral moyamoya disease (n = 20) than the controls and severe MCA stenosis (P < 0.01). Direct observations revealed a marked decrease in the outer diameter of the carotid fork (n = 3). These findings strongly suggest specific shrinkage of the involved arteries in moyamoya disease, which may provide essential information to distinguish moyamoya disease from other intracranial arterial stenosis and shed light on the etiology and novel diagnosis cue of moyamoya disease.

Three dimensional MRI study: Safety of short versus long needle peribulbar anesthesia

BackgroundThe standard technique of Peribulbar block is to use 25g 25mm needle at the junction between the lateral one third and medial two third of the lower orbital rim in the infero-temporal quadrant of the orbit. Theoretically, insertion of longer needles increases the potential of injury to important structure; however, safety of the shorter needle had never been demonstrated. This study describes the anatomy of the orbital structures with magnetic resonance imaging (MRI) using the three-dimensional constructive interference in steady state (3D CISS) sequence to present a morphological basis for needle entry at 12.5 and 25mm lengths. Statistical comparisons were performed at the 12.5 versus 25mm depths. Statistical significance was indicated by P<0.05. MethodFifty patients free of orbital pathology with normal axial length were selected for MRI with the 3D CISS sequence. Original axial and multiplanar image reconstruction (MPR) images were selected for image interpretation. Orbital structures were identified at 12.5 and 25mm depths from the orbital rim to compare significant differences in anatomy between the two imaging planes at the expected needle depth and to assess the size of the globe and the orbit. ResultsThe cross sectional area of the extraocular muscles were statistically significantly smaller at the 12.5mm plane (P=0.001). The area of inferotemporal fat was statistically significantly larger at the 12.5mm plane (P=0.033). There was no statistical difference in the inferonasal and superonasal fat areas at different depths (P=0.34, P=0.35 respectively). The size of the orbit and globe was significantly larger at 12.5mm (P=0.001). There was no difference between depths in the presence or absence of neurovascular bundles and supporting structures including the intramuscular septae. ConclusionThere is a larger structure-free space at a depth of 12.5mm than at 25mm. Therefore, the inference is that a needle inserted in the infero-temporal zone to a depth of 12.5mm is less likely to injure the eyeball or extra-ocular muscles than one advanced to 25mm.

Osteoma of the Internal Auditory Canal Mimicking Vestibular Schwannoma: Case Report and Review of 17 Recent Cases

Osteoma of the internal auditory canal (IAC) is an uncommon benign bone tumor. Its imaging features may be similar to other IAC lesions, such as vestibular schwannomas that are benign and usually slow-growing but sometimes life-threatening tumors. Thus, detecting IAC lesions and differentiating osteoma from other IAC lesions are both important clinically. We report a case of misdiagnosis of an IAC osteoma as an IAC schwannoma based on magnetic resonance (MR) imaging using the three-dimensional constructive interference in steady state (CISS) sequence instead of T1-weighted MR imaging with gadolinium. We also review 17 cases of IAC osteomas reported in the past 22 years. A 61-year-old female was admitted to our department with IAC lesion incidentally discovered by the CISS sequence. The lesion was diagnosed as an IAC schwannoma, and was followed up annually under "wait and scan" management. Follow-up T1-weighted MR imaging with gadolinium showed no enhancement of the tumor, and additional computed tomography (CT) of the temporal bone showed a solitary pedunculated bony lesion, resulting in the diagnosis of IAC osteoma. The CISS sequence is useful for detecting small IAC lesions, such as vestibular schwannomas. However, the CISS sequence has limitations for qualitative diagnosis and can misdiagnose osteomas as schwannomas. Use of the CISS sequence without T1-weighted MR imaging with gadolinium for the screening of a lesion of the IAC and cerebellopontine angle should consider the possibility of IAC osteomas, and temporal bone CT or T1-weighted MR imaging with gadolinium should be performed when an IAC lesion is detected.

Syringomyelia

Syringomyelia is an etiologically diverse affliction caused by disturbance of normal cerebrospinal fluid flow dynamics. An evaluation by comprehensive imaging, using advanced three-dimensional constructive interference in steady state and four-dimensional phase contrast imaging techniques, should be focused on finding the causative lesion because this determines which surgical strategy could be employed. This review discusses the pathogenesis and various etiologies of syringomyelia, and focuses on the specific surgical approach for each, mentioning aspects of surgical complications and prognosis. Particular attention is given to the "persistent central canal," a normal anatomical variant of the persistent fetal configuration of the central canal, as this is increasingly seen nowadays on routine magnetic resonance imaging.

Advanced virtual magnetic resonance imaging (MRI) techniques in neurovascular conflict: bidimensional image fusion and virtual cisternography

The aim of this study was to evaluate the advantages and limits of virtual magnetic resonance techniques in planning surgery for microvascular decompression in patients with neurovascular conflict. Between December 2010 and December 2011, we prospectively observed 32 patients (30 with trigeminal neuralgia and two with hemifacial spasm), with a suspected clinical diagnosis of neurovascular conflict. To assess the contact between nerve and vessel, magnetic resonance imaging (MRI) by three-dimensional (3D) constructive interference in steady state (CISS) and high-resolution MR angiography (MRA) were performed in all cases. Moreover, we performed presurgical simulation of microvascular decompression using MR two-dimensional image fusion and virtual cisternography. The neuroradiological findings were compared with the surgical findings. In all cases, we demonstrated the anatomical relations between cranial nerves and offending vessels with an optimal correlation between radiological and surgical patterns. Advanced virtual MRI techniques, such as image fusion and virtual cisternography, are able to depict the complex anatomical relationships between neural and vascular structures within the cisternal spaces of the skull base. These techniques can be considered an optimal presurgical tool to support traditional MRI evaluation of this region.

Microvascular decompression of the root emerging zone for hemifacial spasm: evaluation by fusion magnetic resonance imaging and technical considerations

The root exit zone (RExZ) of the facial nerve has been considered to be the target in microvascular decompression (MVD) for hemifacial spasm. However, more proximal segments with oligodendrocyte-derived myelin, where the facial nerve root emerges at the pontomedullary sulcus and adheres to the brainstem surface (root emerging zone [REmZ]), may also be susceptible to neurovascular compression. This study evaluated the predictive value of magnetic resonance (MR) imaging in detecting and assessing the features of vascular compression, especially in the pontomedullary sulcus, and describes the technical considerations of MVD procedures for the more proximal segments of the facial nerve. Twenty patients treated with MVD underwent three-dimensional constructive interference in steady-state MR imaging and three-dimensional time-of-flight MR angiography. Their fusion images were used to evaluate the anatomical neurovascular relationships and intraoperative findings were analyzed. Most offending arteries at the REmZ and the RExZ of the facial nerve were correctly identified by fusion MR imaging. During surgery, neurovascular contacts were identified at one or more segments of the facial nerve in all patients. The REmZ of the facial nerve was affected in 55 % of the patients. The most common offending vessel at the REmZ was the posterior inferior cerebellar artery rather than the anterior inferior cerebellar artery. The key procedure to explore the deep-seated REmZ in the pontomedullary sulcus was full dissection of the lower cranial nerves to the brainstem origin. Our definition more correctly describes the specific anatomical relationship of the facial nerve origin from the brainstem and the clinically relevant target for MVD surgery. Fusion MR imaging is very useful to identify neurovascular contacts at both the RExZ and the REmZ of the facial nerve.

The role of the cerebellopontine angle cistern area and trigeminal nerve length in the pathogenesis of trigeminal neuralgia: a prospective case-control study

The aim of this prospective study was to evaluate whether the cerebellopontine angle (CPA) cistern area and trigeminal nerve cisternal length play a role in the pathogenesis of trigeminal neuralgia (TN). High-resolution 1.5 T magnetic resonance imaging of the posterior fossa was performed in 26 patients with TN and 18 age-matched healthy controls. Axial T2-weighted, three-dimensional constructive interference in steady-state (3D-CISS) was used to measure bilaterally the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length. In patients, the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length was smaller on the affected side (p = 0.04). Healthy controls tended to have larger cisternal areas and longer trigeminal nerve lengths than patients (p = 0.059, p = 0.071, respectively). Larger CPA cisternal areas tended to be seen in older patients. There was a strong correlation between the cross-sectional area of the CPA cistern and the length of the trigeminal nerve (p = 0.000). Smaller CPA cisterns and short cisternal trigeminal nerves impact the pathogenesis of essential TN by facilitating the neurovascular conflict, especially in younger patients. Trigeminal nerve cisternal measurement provides an easy and direct estimation of the CPA area. This information can be used for surgical planning and potentially for outcome prediction.

Outer-diameter narrowing of the internal carotid and middle cerebral arteries in moyamoya disease detected on 3D constructive interference in steady-state MR image: is arterial constrictive remodeling a major pathogenesis?

To obtain information on affected vessels in moyamoya disease (MMD), we analyzed the vascular morphological characteristics of MMD using three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance imaging (MRI). The population of this 3D-CISS MRI study consisted of 51 patients with MMD: 16 patients with atherosclerotic middle cerebral artery (MCA) stenosis or occlusion, 42 MRI control patients, and 28 control digital subtraction angiography (DSA) patients. We measured the outer diameters of the terminal portion of the internal carotid artery (ICA) and the proximal portion of the MCA (M1 portion). We evaluated the inner diameter as the relative value (%) obtained from magnified DSA images and analyzed these data. The outer diameters of the ICA and M1 portions were significantly smaller in the MMD group than in the other two groups, while the M1 outer diameter of the atherosclerosis group was not significantly different compared to the control (ICA: MMD, 2.61 ± 0.46 mm vs. control, 4.04 ± 0.50 mm and M1: MMD, 1.92 ± 0.43 mm vs. control, 3.34 ± 0.54 mm vs. atherosclerosis, 3.45 ± 0.56 mm). Furthermore, in MMD patients, the outer diameter was unrelated to the progression of the luminal stenosis grade estimated by DSA. This is the first report that the outer diameters of both the ICA and M1 decrease in MMD patients. Our findings suggest that the vascular constrictive changes of the affected arteries are an important phenomenon reflecting MMD pathology.

Response to: Prognostic indicators of hearing after complete resection of cholesteatoma causing a labyrinthine fistula by Stephenson MF and saliba I. Eur Arch Otorhinolaryngol 2011 Mar 9 [epub ahead of print

Recently, Stephenson and Saliba [1] reported their data on preoperative CT-scanning in cholesteatoma patients with labyrinthine fistula in the article ‘‘Prognostic indicators of hearing after complete resection of cholesteatoma causing a labyrinthine fistula’’. The authors state that high-resolution preoperative CT-scan is very precise in diagnosing labyrinthine fistulas and that its radiologic size helps to predict the type of the fistula. This study is generally well designed and well reported, but we have several comments. The authors mention: ‘‘a further study is needed to identify if a diffusion-weighted sequence for magnetic resonance imaging of labyrinthine cholesteatomatous fistula can predict the effect of the depth on the postoperative hearing outcome after a complete removal of the cholesteatoma’’. Although we consider non-echo-planar diffusion-weighted MRI as an essential tool in the preoperative work-up (and postoperative follow-up) of the cholesteatoma patient, its usefulness for the work-up of labyrinthine fistula in the cholesteatoma patient is limited [2]. Indeed, this sequence does not allow for discrimination of both cholesteatoma and other tissues, such as bone. However, other MRI sequences can be useful. Earlier studies on T1and T2-weighted imaging, gadolinium-enhanced spin-echo, three-dimensional Fourier transformation constructive interference in steady state (3DFT-CISS), and fluid-attenuated inversion recovery (FLAIR) were reported, respectively by Casselman et al. [3], Smadja et al. [4], and Sone et al [5]. In our department, we routinely perform preoperative temporal bone cone-beam CT-scans combined with a full MRI protocol (including non-echo-planar diffusion-weighted MRI) in the cholesteatoma patient [2]. In case of a lateral canal fistula, as diagnosed on CT, we use T2-weighted imaging to evaluate the presence of the labyrinthine fluid. If the labyrinthine fluid in the part of the lateral semicircular canal adjacent to the cholesteatoma is absent (no signal on T2 MRI), this will probably be due to reactive fibrosis. In such cases, the risk for perioperative sensorineural hearing loss is lower because the matrix and perimatrix of the cholesteatoma are not directly in contact with the membranous labyrinth. In case the fluid is still present (high signal on T2 MRI), the risk for a perioperative sensorineural hearing loss is higher because the matrix and perimatrix of the cholesteatoma can be in direct contact with the fluid contents of the membranous labyrinth, depending on the extent of the fistula. Our preoperative counseling of the patient is based on this policy [6]. A further study on the use of preoperative MRI in lateral canal fistula is definitely feasible and should, in our opinion, focus on T2-weighted imaging instead of diffusionweighted imaging. Additionally, the role of the cone-beam CT-scan should be further studied because of the increased spatial resolution and the significant decrease in radiation dosage. V. Van Rompaey E. Offeciers (&) University Department of Otorhinolaryngology and Head and Neck Surgery, Sint Augustinus Hospital, Oosterveldlaan 24, Wilrijk, 2610 Antwerp, Belgium e-mail: erwin.offeciers@gza.be

Idiopathic Hypoglossal Nerve Laceration Detected by High-Resolution Three-Dimensional Constructive Interference in Steady State Magnetic Resonance Imaging

A 55-year-old man presented with acute onset dysarthria caused by left hypoglossal palsy. He had neither surgery nor injury prior to the onset of his symptoms. We detected no abnormalities with conventional magnetic resonance imaging (MRI) except for a slight gadolinium enhancement of the left hypoglossal nerve. Three-dimensional constructive interference in steady state MRI (CISS MRI) showed curling and thickening of the left hypoglossal nerve and fluid accumulation in the hypoglossal nerve canal. A systemic survey found no malignancies. After 8 months, sustained left hypoglossal palsy and no change in the MRI led to the diagnosis of idiopathic hypoglossal nerve laceration with evulsion. In such patients, the cause of the defect is not always apparent and 3-dimensional CISS MRI may resolve this issue.

Accuracy of 3.0 Tesla magnetic resonance imaging in the diagnosis of intracochlear schwannoma

Intracochlear schwannomas (ICSs) are rare tumors. The diagnosis of ICS is based on high-resolution magnetic resonance imaging (MRI), which should be used for the accurate determination of the location of tumors. Recent advancements in imaging technologies and software enable the precise regional diagnosis of ICS. We experienced a case of intracochlear schwannoma with a diagnosis of progressive hearing loss and tinnitus. Audiometry revealed severe hearing loss in the right ear with remaining low-frequency hearing. MRI showed an abnormal lesion in the cochlea. Three-dimensional real inversion recovery (3D rIR) and constructive interference in steady state (CISS) MRI revealed the size and shape of the tumor via identification of the cochlear nerve and cochlear fluid space. CISS and 3D rIR sequences provide useful information regarding the boundaries of tumors and the tissues that surround them.

Phase-contrast MRI and 3D-CISS versus contrast-enhanced MR cisternography for the detection of spontaneous third ventriculostomy

To compare the diagnostic efficacies of phase-contrast MRI (PC-MRI) and three-dimensional constructive interference in steady-state (3D-CISS) sequence for the detection of spontaneous third ventriculostomy (STV) on the basis of contrast-enhanced MR cisternography (MRC). Eleven obstructive hydrocephalus patients with clinically-radiologically suspected STV and ten controls were examined by PC-MRI, 3D-CISS and MRC. PC-MRI and 3D-CISS sequence were applied to view the third ventricle and basal cisterns. Following injection of 0.5-1ml intrathecal Gd-DTPA injection, postcontrast MRC images were obtained in three planes. Presence of STV was scored as follows: grade 0, no existence of STV; grade 1, STV present. Results of PC-MRI and 3D-CISS were compared with the MRC findings. In PC-MRI, five patients were assessed as grade 0 and six cases grade 1. As a result of 3D-CISS sequence, eight cases were evaluated as grade 0 and three cases grade 1. Based on MRC, nine cases were assessed as grade 0 and two cases grade 1. False positivity was found in four cases by PC-MRI and in one case by 3D-CISS. The sensitivity, specificity and accuracy of PC-MRI and 3D-CISS sequence regarding demonstration of STV, were 100, 100, 56, 89, 64, and 91% respectively. PC-MRI and 3D-CISS are helpful in confirming the STV. PC-MRI and 3D-CISS should be the first preference. If PC-MRI and 3D-CISS give negative results, then MRC is not required. MRC should be performed on patients who demonstrate suspected STV findings on PC-MRI and 3D-CISS sequences. MRC may prevent false positive results.

MRI and MR sialography of juvenile recurrent parotitis

Juvenile recurrent parotitis (JRP) is the second most common inflammatory salivary gland disease of childhood, after mumps. Diagnosis of JRP is usually based on clinical history of recurrent unilateral or bilateral parotid swelling and demonstration of sialectasis. Conventional sialography, digital sialography, US, MRI and sialoendoscopy have been used as investigative tools for the diagnosis of JRP. MR sialography is increasingly recognized as a useful supplement to sialography in salivary duct disorders. To describe the MRI and MR sialographic findings in children with JRP. MR Sialography was performed using T2-weighted three-dimensional constructive interference in steady-state (CISS) and half fourier acquisition single-shot turbo spin-echo (HASTE) sequences in 62 children with inflammatory salivary gland disease. Out of these 62 children, 6 had JRP. Axial T1- and T2-W images were also performed. The main parotid duct was normal in all six children with JRP. High signal intensity focal lesions suggestive of sialectasis were seen involving both parotid glands in all six children. CISS sequence demonstrated the intraglandular ducts and sialectasis better than HASTE images. MRI and MR sialography can non-invasively delineate the parenchymal and ductal system abnormalities of the parotid glands in children with JRP. Although MR and MR sialography cannot substitute US, they can accurately depict findings such as sialectasis and signal intensity changes in the parotid gland depending upon the phase of the disease (acute vs. chronic inflammation). The radiologist should be familiar with MR findings of JRP.

High resolution MR for evaluation of lower urogenital tract malformations in infants and children: Feasibility and preliminary experiences

Introduction This retrospective study aimed to assess the value of supplementing heavily T2-weighted, high resolution MR-imaging for detailed anatomic assessment in paediatric lower urogenital tract (UGT) malformations. Patients/methods Sixteen patients (6 male and 10 female, median age = 1.8 years, range = 0–9 years) with suspected malformations of the lower UGT who were retrospectively identified from the PACS underwent a clinically indicated standard MR-urography study. In order to facilitate a better anatomic assessment of questioned specific lower UGT structures, an additional three-dimensional Constructive Interference in Steady State-sequence (3D-CISS) had been acquired in these patients. The final diagnosis was established by all imaging results and surgical or laprascopic findings. The findings from the CISS-sequence were compared to the results from standard MR-urography for complementary anatomic information and conspicuity. Results Diagnostic 3D-CISS image quality was achieved in all patients. The 3D-CISS confirmed an ectopic ureteral insertion in six patients and reliably excluded ectopic insertion in 10 patients, whereas conventional MR-urography showed an ectopic insertion of the ureter in one case. In six patients with retrovesical complex formations (suspicious for an ectopic cystic renal bud or a cystic genital structure) the 3D-CISS showed increased conspicuity scores for image quality. Conclusion The additional 3D-CISS-sequence increases the diagnostic yield in the pelvis in children with complex malformations of the lower UGT such as ectopic ureteral insertion or suspected cystic renal or genital malformations at only minimal additional time, compared to standard MR-urography.

Evaluation of cochlear nerve size by magnetic resonance imaging in elderly patients with sensorineural hearing loss

We aimed to determine any differences, if present, between the cross-sectional area of the cochlear nerve (CN) of elderly patients with sensorineural hearing loss (SNHL) and of young patients with normal hearing. The study group included ten patients with age-related SNHL. Fourteen volunteer individuals with normal hearing were recruited as the control group. T1-weighted, T2-weighted and parasagittal three-dimensional Fourier transformation constructive interference in steady state (3DFT-CISS) reconstruction images of all cases were evaluated. Images were examined for any abnormality of CN. The data obtained for each ear with clinical, radiological and audiometric examinations were evaluated. The mean CN cross-sectional area was measured as 0.0252 cm(2) in the control group, whereas that in the SNHL group was 0.0232 cm(2). Although speech discrimination scores showed significant differences, no statistically significant difference was observed for the CN cross-sectional area (p=0.0616). Likewise, there was no difference in CN calibre between male and female patients. The 3DFT-CISS sequence yields superior results in CN imaging. Acquired SNHL may not present with significant changes in CN size on magnetic resonance imaging (MRI).

Phase-contrast MRI and 3D-CISS versus contrast-enhanced MR cisternography on the evaluation of the aqueductal stenosis

In the current study, we aimed to compare the diagnostic efficacies of phase-contrast magnetic resonance imaging (PC-MRI) and three-dimensional constructive interference in steady-state (3D-CISS) sequence over detection of aqueductal stenosis (AS) on the basis of contrast-enhanced magnetic resonance cisternography (MRC). Twenty-five patients with clinically and radiologically suspected AS were examined by PC-MRI, 3D-CISS, and MRC. Axial-sagittal PC-MRI and sagittal 3D-CISS were applied to view the cerebral aqueduct. Following injection of 0.5-1 ml intrathecal gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) injection, postcontrast MRC images were obtained in three planes in early and late phases. Aqueductal patency was scored as follows: grade 0, normal; grade 1, partial narrowing; and grade 2, complete obstruction. Results of PC-MRI and 3D-CISS were compared with the findings of MRC. In PC-MRI, seven cases were assessed as grade 0, 16 cases grade 1, and two cases grade 2. As a result of 3D-CISS sequence, eight cases were evaluated as grade 0, 12 cases grade 1, and five cases grade 2. Based on MRC, nine cases were assessed as grade 0, whereas nine and seven cases were evaluated to be grades 1 and 2, respectively. Five cases that demonstrated partial patency in PC-MRI or 3D-CISS showed complete obstruction by MRC. PC-MRI is helpful in confirming the AS. However, positive flow does not necessarily exclude the existence of AS. 3D-CISS sequence provides excellent cerebrospinal fluid-to-aqueduct contrast, allowing detailed study of the anatomic features of the aqueduct. MRC should be performed on patients who demonstrate suspected AS findings on PC-MRI and/or 3D-CISS sequences.