Mari Hagiwara

Advanced Liver Fibrosis: Diagnosis with 3D Whole-Liver Perfusion MR Imaging—Initial Experience

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively evaluate sensitivity and specificity of various estimated perfusion parameters at three-dimensional (3D) perfusion magnetic resonance (MR) imaging of the liver in the diagnosis of advanced liver fibrosis (stage >or= 3), with histologic analysis, liver function tests, or MR imaging as the reference standard. Whole-liver 3D perfusion MR imaging was performed in 27 patients (17 men, 10 women; mean age, 55 years) after dynamic injection of 8-10 mL of gadopentetate dimeglumine. The following estimated perfusion parameters were measured with a dual-input single-compartment model: absolute arterial blood flow (F(a)), absolute portal venous blood flow (F(p)), absolute total liver blood flow (F(t)) (F(t) = F(a) + F(p)), arterial fraction (ART), portal venous fraction (PV), distribution volume (DV), and mean transit time (MTT) of gadopentetate dimeglumine. Patients were assigned to two groups (those with fibrosis stage <or= 2 and those with fibrosis stage >or= 3), and the nonparametric Mann-Whitney test was used to compare F(a), F(p), F(t), ART, PV, DV, and MTT between groups. Receiver operating characteristic curve analysis was used to assess the utility of perfusion estimates as predictors of advanced liver fibrosis. There were significant differences for all perfusion MR imaging-estimated parameters except F(p) and F(t). There was an increase in F(a), ART, DV, and MTT and a decrease in PV in patients with advanced fibrosis compared with those without advanced fibrosis. DV had the best performance, with an area under the receiver operating characteristic curve of 0.824, a sensitivity of 76.9% (95% confidence interval: 46.2%, 94.7%), and a specificity of 78.5% (95% confidence interval: 49.2%, 95.1%) in the prediction of advanced fibrosis.

Neurosarcoidosis: presentations and management.

Background:Sarcoidosis affects the central nervous system more frequently than previously appreciated. The diagnosis of neurosarcoidosis is often delayed, potentially leading to serious complications. Symptoms, when present, are not specific, may be subtle and resemble those of other neurologic diseases. Review Summary:During the past decade, significant progress has been made in understanding the epidemiology and pathophysiology of neurosarcoidosis, as well as the ability to diagnose and treat this disease. Studies have shown that the optimal diagnostic imaging modality for neurosarcoidosis is magnetic resonance imaging with gadolinium as it enhances visualization of granulomatous infiltration in neural tissue. Subclinical neurosarcoidosis may not be uncommon in patients with sarcoidosis. It is now evident that neurosarcoidosis does not invariably present as a catastrophic event. Adverse effects associated with high-dose systemic corticosteroids, the standard therapy, have discouraged practitioners from initiating treatment in the absence of significant symptomatic neurologic disease. However, other immunosuppressive agents as well newer biologic agents have emerged as an effective, well-tolerated therapeutic alternative to corticosteroids, which are often effective in corticosteroid-recalcitrant cases. Conclusion:Neurologists should be aware of the varying presentations of neurosarcoidosis since early recognition of neurologic involvement in patients with undiagnosed or proven sarcoidosis is currently possible and critical to the prevention of disabling complications.

Imaging the Facial Nerve: A Contemporary Review

Imaging plays a critical role in the evaluation of a number of facial nerve disorders. The facial nerve has a complex anatomical course; thus, a thorough understanding of the course of the facial nerve is essential to localize the sites of pathology. Facial nerve dysfunction can occur from a variety of causes, which can often be identified on imaging. Computed tomography and magnetic resonance imaging are helpful for identifying bony facial canal and soft tissue abnormalities, respectively. Ultrasound of the facial nerve has been used to predict functional outcomes in patients with Bells palsy. More recently, diffusion tensor tractography has appeared as a new modality which allows three-dimensional display of facial nerve fibers.

Contrast-Enhanced Radial 3D Fat-Suppressed T1-Weighted Gradient-Recalled Echo Sequence Versus Conventional Fat-Suppressed Contrast-Enhanced T1-Weighted Studies of the Head and Neck

OBJECTIVE Traditional fat-suppressed T1-weighted spin-echo or turbo spin-echo (TSE) sequences (T1-weighted images) may be degraded by motion and pulsation artifacts in head-and-neck studies. Our purpose is to evaluate the role of a fat-suppressed T1-weighted 3D radial gradient-recalled echo sequence (radial-volumetric interpolated breath-hold examination [VIBE]) in the head and neck as compared with standard contrast-enhanced fat-suppressed T1-weighted images. MATERIALS AND METHODS We retrospectively evaluated 21 patients (age range, 9-67 years) who underwent head-and-neck MRI at 1.5 T. Both contrast-enhanced radial-VIBE and conventional fat-suppressed TSE contrast-enhanced T1-weighted imaging were performed. Two radiologists evaluated multiple parameters of image quality, graded on a 5-point scale. Mixed-model analysis of variance and interobserver variability assessment were performed. RESULTS The following parameters were scored as significantly better for the contrast-enhanced radial-VIBE sequence than for conventional contrast-enhanced T1-weighted imaging: overall image quality (p < 0.0001), degree of fat suppression (p = 0.006), mucosal enhancement (p = 0.004), muscle edge clarity (p = 0.049), vessel clarity (p < 0.0001), respiratory motion artifact (p = 0.002), pulsation artifact (p < 0.0001), and lesion edge sharpness (p = 0.004). Interobserver agreement in qualitative evaluation of the two sequences showed fair-to-good agreement for the following variables: overall image quality (intraclass correlation coefficient [ICC], 0.779), degree of fat suppression (ICC, 0.716), mucosal enhancement (ICC, 0.693), muscle edge clarity (ICC, 0.675), respiratory motion artifact (ICC, 0.516), lesion enhancement (ICC, 0.410), and lesion edge sharpness (ICC, 0.538). Excellent agreement was shown for vessel clarity (ICC, 0.846) and pulsation artifact (ICC, 0.808). CONCLUSION The radial-VIBE sequence is a viable motion-robust improvement on the conventional fat-suppressed T1-weighted sequence.

Potential Role of PET/MRI for Imaging Metastatic Lymph Nodes in Head and Neck Cancer

OBJECTIVE This article explores recent developments in PET and MRI, separately or combined, for assessing metastatic lymph nodes in patients with head and neck cancer. CONCLUSION The synergistic role of PET and MRI for imaging metastatic lymph nodes has not been fully explored. To facilitate the understanding of the areas that need further investigation, we discuss potential mechanisms and evidence reported so far, as well as future directions and challenges for continued development and clinical research.

MR assessment of oral cavity carcinomas.

Approximately half of head and neck carcinomas arise from the oral cavity. Imaging plays an essential role in the preoperative evaluation of oral cavity carcinomas. MR imaging is particularly advantageous in the evaluation of the oral cavity, with better depiction of the anatomy in this region and reduction of dental artifacts compared with CT. MR is also the preferred imaging modality for the evaluation of bone marrow invasion and perineural tumor spread, which are findings critical for treatment planning. Advanced MR imaging techniques may potentially better delineate true tumor extent, determine lymph node metastases, and predict treatment response.

Reformatted Computed Tomography to Assess the Internal Nasal Valve and Association With Physical Examination

OBJECTIVES To assess the cross-sectional area and angle of the internal nasal valve more accurately by reformatting computed tomography (CT) scans of the nasal airway according to a more appropriate orientation than scans traditionally sectioned in the coronal plane and then to compare the results with clinical data on the nasal valve obtained from physical examination. METHODS We performed a retrospective review of the medical records of 24 rhinoplasty patients treated at a private practice facial plastic surgery office affiliated with a tertiary care university hospital. The patients had fine-cut (0.75-mm section) CT scans ordered for nasal airway obstruction or nasal valve compromise at the same institution. These patients were evaluated from January 1, 2000, through December 31, 2010. The previously acquired CT scans were reformatted to obtain sections through the internal nasal valve at a more appropriate orientation. The internal nasal valve cross-sectional area and valve angle were measured through a standardized section (1 cut immediately anterior to the head of the inferior turbinate) from the reformatted scans. The cross-sectional area was also measured through the same point on the traditionally oriented CT scan, and the values were compared. The results from each patients scan were compared with data from the patients medical record and analyzed against the patients preoperative modified Cottle examination findings. RESULTS The CT scans oriented in the reformatted plane through the internal nasal valve provided a narrower valve angle than the traditionally oriented CT scans and more closely approximated the hypothesized true value of the internal nasal valve of 10° to 15° (P < .001). In a comparison of the same-side internal nasal valve angle and cross-sectional nasal valve area between the 2 different CT scan orientations, a statistically significant difference in the internal nasal valve angles between the 2 scan orientations was discovered, but this finding did not reach significance when distinguishing the nasal valve cross-sectional area. Finally, no correlation was found with regard to the preoperative modified Cottle maneuver scores for the internal nasal valve angle and cross-sectional valve area values in either scan orientation. CONCLUSIONS Precise preoperative evaluation of the internal nasal valve is critical to the workup for reconstruction or repair of problems that involve this area. Although tools such as acoustic rhinometry exist to evaluate the cross-sectional area of the nasal valve, many rhinoplasty surgeons do not have access to this expensive equipment. A CT scan with reformatting in the proper plane of the internal nasal valve can provide the surgeon with improved anatomical information to assess that region. With this in mind, however, the surgeon should always perform a thorough preoperative physical examination and treat the patient and his or her symptoms, not the imaging studies, when considering a candidate for a surgical intervention.

Evaluation of the orbit using contrast-enhanced radial 3D fat-suppressed T1 weighted gradient echo (Radial-VIBE) sequence

OBJECTIVE Contrast-enhanced fat-suppressed T1 weighted (T1W) two-dimensional (2D) turbo spin echo (TSE) and magnetization-prepared gradient echo (MPRAGE) sequences with water excitation are routinely obtained to evaluate orbit pathology. However, these sequences can be marred by artefacts. The radial-volume-interpolated breath-hold examination (VIBE) sequence is a motion-robust fat-suppressed T1W sequence which has demonstrated value in paediatric and body imaging. The purpose of our study was to evaluate its role in assessing the orbit and to compare it with routinely acquired sequences. METHODS A Health Insurance Portability and Accountability Act-compliant and institutional review board-approved retrospective study was performed in 46 patients (age range: 1-81 years) who underwent orbit studies on a 1.5-T MRI system using contrast-enhanced Radial-VIBE, MPRAGE and 2D TSE sequences. Two radiologists blinded to the sequence analysed evaluated multiple parameters of image quality including motion artefact, degree of fat suppression, clarity of choroidal enhancement, intraorbital vessels, extraocular muscles, optic nerves, brain parenchyma and evaluation of pathology. Each parameter was assessed on a 5-point scale, with a higher score indicating the more optimal examination. Mix model analysis of variance and interobserver variability were assessed. RESULTS Radial-VIBE demonstrated superior quality (p < 0.001) for all orbit parameters when compared with MPRAGE and 2D TSE. Interobserver agreement demonstrated average fair-to-good agreement for degree of motion artefact (0.745), fat suppression (0.678), clarity of choroidal enhancement (0.688), vessels (0.655), extraocular muscles (0.675), optic nerves (0.518), brain parenchyma (0.710) and evaluation of pathology (0.590). CONCLUSION Radial-VIBE sequence demonstrates superior image quality when evaluating the orbits as compared with conventional MPRAGE and 2D TSE sequences. ADVANCES IN KNOWLEDGE Radial-VIBE employs unique non-Cartesian k-space sampling in a radial or spoke-wheel fashion which provides superior image quality improving diagnostic capability in the evaluation of the orbits.

Identification of endolymphatic hydrops in Ménière's disease utilizing delayed postcontrast 3D FLAIR and fused 3D FLAIR and CISS color maps.

Objective The preferential delayed enhancement of the perilymphatic space enables detection of the non-enhancing endolymphatic hydrops present in patients with Ménière’s disease. The aim of this study was to evaluate the diagnostic utility of delayed postcontrast 3D FLAIR images and a color map of fused postcontrast FLAIR and constructive interference steady state (CISS) images in the identification of endolymphatic hydrops in patients with clinically diagnosed Ménière’s disease. Study Design Case control, blinded study. Setting Tertiary referral center. Patients Ten patients with Ménière’s disease and five volunteer controls. Intervention Diagnostic. Main Outcome Measure Two neuroradiologists blinded to the clinical history independently evaluated for the presence of endolymphatic hydrops on the images of both inner ears for test and control subjects. Both the standard gray-scale FLAIR images and the fused color map images were independently reviewed. Results The gray-scale 3D FLAIR images demonstrated 68.2% sensitivity and 97.4% specificity, and the fused color map images demonstrated 85.0% sensitivity and 88.9% specificity in the identification of endolymphatic hydrops in Ménière’s disease. There was significant correlation between the gray-scale 3D FLAIR images and fused color map images with the categorization of involvement (p = 0.002). Inter-evaluator reliability was excellent (kappa = 0.83 for gray-scale images, kappa = 0.81 for fused color map). Conclusion Delayed 3D FLAIR and fused 3D FLAIR-CISS color map images of the inner ears after intravenous contrast administration are potentially useful diagnostic tools in the evaluation of patients with suspected Ménière’s disease.

Spontaneous Intracranial Hypotension Presenting With Severe Sensorineural Hearing Loss and Headache

A 50-year-old woman presented with worsening right hearing loss, aural fullness, and bilateral tinnitus. Nine years before presentation, the patient was involved in 2 motor vehicle accidents and subsequently complained of chronic nonpostural headaches. Audiograms demonstrated an initial right mild low-frequency sensorineural hearing loss (SNHL) progressing to downsloping mildto-profound SNHL for 4 years (Fig. 1). Acoustic reflexes were absent. No abnormalities were noted on physical examination or laboratory testing, including basic chemistries, complete blood cell count, thyroid-stimulating hormone, rapid plasma reagin, fluorescent treponemal antibody absorption, Lyme titers, antinuclear antibodies, and erythrocyte sedimentation rate. Magnetic resonance image (MRI) revealed a caudally displaced brain, with descent of cerebellar tonsils, crowding of the foramen magnum and near complete effacement of the interpeduncular cisterns (Fig. 2A). There was diffuse dural enhancement and venous engorgement present on the gadolinium-enhanced T1-weighted image, notably extending into the right internal auditory canal (Fig. 2, B and C). There was no evidence of a mass lesion in the internal auditory canals or cerebellopontine angles (Fig. 2, C and D). Similar findings were noted on a previous MRI 1.5 years after her second motor vehicle crash.