Dynamic Magnetic Resonance Imaging Studies Research Articles

Diagnosis and treatment of chronic subdural hematomas in elderly and senile age patients (own experience and current global trends)

Objective ‒ to improve the treatment of chronic subdural hematoma (CSDH) in older people.Materials and methods. Retrospective analysis of the results of diagnosis and treatment of patients with CSDH treated in the Department of Neurotrauma of Romodanov Institute of Neurosurgery NAMS of Ukraine and Zaporizhzhya City Hospital for Emergency and Emergency Medicine in 2010–2019 was performed. The distribution by age was as follows: elderly patients – 80, patients senile age – 32, long-lived – 6. Multislice computed tomography was made in 86.7 % of patients, magnetic resonance imaging ‒ in 13.3 %. In 118 cases different types and volumes of surgical intervention were performed, in 58 ‒ conservative treatment.Results. The indication for surgery in elderly and senile patients with CSDH is the presence of hematoma ≥100 cm3 in the absence of dislocation syndrome. Concomitant somatic diseases were revealed in 95 % of cases. Treatment efficacy was monitored by dynamic magnetic resonance imaging studies (in 73.5 % cases) and multislice computed tomography (in 26.5 %). A comprehensive clinical and neurological examination was performed according to the modified Rankine scale, the Glasgow extended consequences scale, calculation of the Barthel index, after 1, 3 and 6 months. Postoperative complications: CSDH recurrence in 10 (6.0%) patients, mostly older than 60 years, pneumocephalus ‒ in 1 (0.84 %), meningoencephalitis ‒ in 1 (0.84 %) patients. Postoperative mortality was 6.8 % (8 cases). Conclusions. When choosing a method of treatment should be considered etiopathogenetic factors of hematoma formation, the severity of neuroimaging characteristics of CSDH, the degree of displacement of midline structures and neurological symptoms, somatic risks and the patient’s consent. The choice of treatment tactics for the elderly and senile is based not only on the Glasgow consequences scale and Markwalder grading score, but also on the scale of A.K. Thotakura et al. (Displacement of median structures and hematoma density (on the Hounsfield scale)). Removal of the hematoma is the main method of treating CSDH, aspiration of CSDH through burr holes followed by passive drainage is the method of choice. Conservative treatment of CSDH according to clear indications can be used both alone and in combination with surgical treatment.

Perfusion Defects and Collateral Flow Patterns in Acute Small Subcortical Infarction: a 4D Dynamic MRI Study

The hemodynamic changes of acute small subcortical infarction (SSI) are not well understood. We evaluate the hemodynamic changes and collaterals in acute SSI using perfusion magnetic resonance imaging (MRI). A total of 103 patients with acute SSI in penetrating artery territories were recruited and underwent MRI within 24 h of stroke onset. Using 4D dynamic perfusion MRI, they were divided into three patterns: 25 (24%) with normal perfusion, 31 (30%) with compensated perfusion, and 47 (46%) with hypoperfusion. The development of anterograde or retrograde collaterals was also evaluated. Patients with hypoperfusion pattern had the highest rate of early neurological deterioration (32%, p = 0.007), the largest initial and final infarction volumes (p < 0.001 and p = 0.029), the lowest relative cerebral blood flow (0.63, p < 0.001), and the lowest rate of anterograde and retrograde collaterals (19%, p < 0.001; 66%, p = 0.002). The anterograde collaterals were associated with higher relative cerebral blood volume (0.91 vs. 0.77; p = 0.024) and a higher rate of deep cerebral microbleeds (48 vs. 21%; p = 0.028), whereas retrograde collaterals were associated with higher systolic and diastolic blood pressure (p = 0.031 and 0.020), smaller initial infarction volume (0.81 vs. 1.34 ml, p = 0.031), and a higher rate of lobar cerebral microbleeds (30 vs. 0%; p = 0.013). Both anterograde and retrograde collaterals may play a critical role in maintaining cerebral perfusion and can have an impact on patient clinical outcomes. Further studies are warranted to verify these findings and to investigate effective treatments.

Evaluation of Golden-Angle-Sampled Dynamic Contrast-Enhanced MRI Reconstruction Using Objective Image Quality Measures: A Simulated Phantom Study.

We aim to extend the use of image quality metrics (IQMs) from static magnetic resonance imaging (MRI) applications to dynamic MRI studies. We assessed the use of 2 IQMs, the root mean square error and structural similarity index, in evaluating the reconstruction of quantitative dynamic contrast-enhanced (DCE) MRI data acquired using golden-angle sampling and compressed sensing (CS). To address the difficulty of obtaining ground-truth knowledge of parameters describing dynamics in real patient data, we developed a Matlab simulation framework to assess quantitative CS-DCE-MRI. We began by validating the response of each IQM to the CS-MRI reconstruction process using static data and the performance of our simulation framework with simple dynamic data. We then extended the simulations to the more realistic extended Tofts model. When assessing the Tofts model, we tested 4 different methods of selecting a reference image for the IQMs. Results from the retrospective static CS-MRI reconstructions showed that each IQM is responsive to the CS-MRI reconstruction process. Simulations of a simple contrast evolution model validated the performance of our framework. Despite the complexity of the Tofts model, both IQM scores correlated well with the recovery accuracy of a central model parameter for all reference cases studied. This finding may form the basis of algorithms for automated selection of image reconstruction aspects, such as temporal resolution, in golden-angle-sampled CS-DCE-MRI. These further suggest that objective measures of image quality may find use in general dynamic MRI applications.

Evaluation of the effect of abdominal sacrocolpopexy (ASC) on urethral anatomy and continence mechanism using dynamic MRI.

Treatment of pelvic organ prolapse (POP) associated with stress urinary incontinence (SUI) is a surgical challenge. Surgeons may perform combined prolapse and incontinence surgery or may correct prolapse first and evaluate incontinence afterwards. We present a prospective study to evaluate the effect of abdominal sacrocolpopexy (ASC) on urethral anatomy and continence using dynamic magnetic resonance imaging (MRI). Twenty females with concomitant apical prolapse and SUI due to urethral hypermobility were included. Patients with intrinsic sphincteric deficiency (ISD) were excluded. All patients underwent ASC operation as a sole treatment without anti-incontinence procedure. Patients were informed they may need anti-incontinence procedure afterwards. Symptom-specific questionnaires assessing prolapse, incontinence, sexual function and quality of life (QoL), dynamic MRI and pressure flow urodynamic study were administered before and after surgery. Mean age was 53years. All patients had apical prolapse; four with cystocele, and five with rectocele. Urethral hypermobility was positive in all patients. After performing ASC, all patients reported significant improvement of all prolapse and incontinence questionnaires as well as QoL and sexual function. Significant improvement of incontinence parameters on dynamic MRI (bladder neck descent, posterior urethrovesical angle and urethral inclination angle) was observed after ASC. Similarly, significant change in the position of the leading edge of prolapse and anorectal junction was observed. In patients with prolapse and urethral hypermobility, ASC may return bladder neck and urethral anatomy towards normal as proved by dynamic MRI. However, further studies on larger number of patients with longer follow-up period are required.

Multiple Burr-Hole Surgery for the Treatment of Moyamoya Disease and Quasi-Moyamoya Disease in Children: Preliminary Surgical and Imaging Results

Moyamoya disease (MMD) is characterized by a progressive spontaneous occlusion of distal internal carotid arteries and its main branches. It is necessary to promptly diagnose and treat this condition, especially in children, because of the high risk of stroke and consequent severe disability. In this study, we examine the role of multiple burr-hole surgery (MBHS) in the treatment of pediatric patients with MMD and quasi-MMD and the role of perfusion magnetic resonance imaging (MRI) in the surgical indication and during follow-up. We reviewed preoperative, early postoperative, and late postoperative MRI perfusion and digital subtraction angiography images together with clinical and surgical outcomes in 10 children with MMD treated by MBHS. Fourteen MBHS procedures (6 unilateral, 2 bilateral, and 2 single-setting bilateral) were performed in 10 children. Clinical and radiologic follow-up for all patients ranges from 16 months to 7 years. No ischemic events (transient ischemic attacks or stroke) occurred during the follow-up period. Postoperative digital subtraction angiography showed good revascularization around the burr-hole sites in all patients. The functional efficacy of the surgery was confirmed by dynamic susceptibility contrast perfusion MRI studies in 8 patients. Our data underline the good rate of success of MBHS in pediatric MMD and quasi-MMD. This technique results in good collateral revascularization, improved cerebral perfusion and excellent short and long-term symptoms control, with low perioperative risk. Postoperative changes of perfusion parameters and ivy sign MRI finding seem to show a positive correlation and mainly occur in posterior middle cerebral artery territory.

Evaluation of the effect of electrical stimulation combined with biofeedback therapy for postpartum pelvic organ prolapse: a static and dynamic magnetic resonance imaging study

Objective: To explore the clinical value of static and dynamic magnetic resonance imaging (MRI) in evaluating the effect of electrical stimulation combined with biofeedback in the treatment of pelvic organ prolapse postpartum. Methods: A total of 50 primiparas diagnosed as pelvic organ prolapse postpartum from February 2016 to November 2017 were randomly divided into treatment group (24 cases) and control group (26 cases). The control group recovered spontaneously, and the treatment group received electric stimulation combined with biofeedback therapy (6 weeks). All subjects underwent static and dynamic MRI before and after treatment. The thickness of bilateral puborectal muscles, levator ani hiatus area (LHA), H line, M line and levator ani plate angle (LPA) were respectively measured in rest state and strain state at 42 days and 12 weeks postpartum, and the differences of parameters were compared between two groups. Results: (1) Compared with 42 days postpartum, the effective rate of pelvic organ prolapse was 15.4% (4/26) in the control group and 62.5% (15/24) in the treatment group, which was significantly higher than that of the control group (P<0.01). (2) Compared with 42 days postpartum, the thickness of bilateral puborectal muscles in the treatment group increased at 12 weeks postpartum, while that of the H line, LHA, M line and LPA in strain state decreased. (3) At 12 weeks postpartum, the thickness of the bilateral puborectal muscle in the treatment group was greater, and LHA, M line, and LPA in strain state were less than that in the control group (all P<0.05). Conclusion: Electrical stimulation combined with biofeedback therapy can improve pelvic organ prolapse due to vaginal delivery, and the static and dynamic MRI can objectively evaluate the effect of pelvic floor rehabilitation therapy on improving the pelvic floor supporting structure and function, providing an important support and guidance for restoration of postpartum pelvic organ prolapse.

A Dynamic Magnetic Resonance Imaging Study of Changes in Severity of Cervical Spinal Stenosis in Flexion and Extension.

ObjectiveTo evaluate changes in the severity of cervical spinal stenosis (CSS) in flexion and extension and determine whether the rate of change with motion varied with severity.MethodsThe study included 92 symptomatic patients with a mean age of 57.80±10.41, who underwent cervical spine dynamic magnetic resonance imaging. The severity of stenosis was evaluated using a semi-quantitative CSS score, ranging from 0 (no spinal stenosis) to 18 (severe stenosis). Radiological evaluation included flexion, neutral, and extension measurements, as determined by the C2–C7 Cobb angle. The severity of stenosis was represented by the total CSS score. The total CSS score in flexion, neutral, and extension positions was compared using repeated measures one-way analysis of variance. The change rate of stenosis per angle motion (CRSPAM) was defined as change in total CSS score divided by change in Cobb angle. The correlation of CRSPAM with severity of stenosis, represented by total CSS score in neutral position, was evaluated using Pearson correlation analysis.ResultsThe total CSS score was significantly higher in extension (6.04±2.68) than in neutral position (5.25±2.47) (p<0.001), and significantly higher in neutral than in flexion position (4.40±2.45) (p<0.001). The CRSPAM was significantly and positively correlated with total CSS score in neutral position in the flexion-extension range (r=0.22, p=0.04) and flexion-neutral range (r=0.27, p=0.01).ConclusionIn symptomatic CSS patients, the radiological severity of stenosis increases with extension and decreases with flexion. In patients with CSS, the rate of variation in spinal stenosis increases with increased severity.

Can Dynamic MRI Be Used to Accurately Identify Velopharyngeal Closure Patterns?

Dynamic magnetic resonance imaging (MRI) has been proposed as a non-invasive, child-friendly, reproducible, and repeatable imaging method providing a 3-dimensional view of the velopharyngeal structures and function during speech. However, the value of dynamic MRI as compared to imaging methods such as nasopharyngoscopy is not well understood. The aim of this study was to compare the ability of nasopharyngoscopy and dynamic MRI to accurately identify velopharyngeal closure patterns among adults without cleft palate. Participants included 34 healthy adults with normal anatomy between 19 and 33 years of age (mean = 23 years; SD = 4.1 years). Participants underwent dynamic MRI and nasopharyngoscopy studies and comparisons were performed to determine the intra- and inter-rater reliability for accurately determining closure pattern. The MRI acquisition was a dynamic acquisition of a 2D plane. Strong inter- (κ = .824; P < .001) and intra-rater (Rater 1: κ = 0.879, P < .001, 94% agreement between ratings; Rater 2 with 100% agreement) agreement was observed for the identification of closure pattern using nasopharyngoscopy. Inter-rater agreement for ratings using MRI demonstrated moderate agreement (κ = .489; P < .004). Examining point agreement revealed only 27 of the 33 ratings of MRI showed agreement (80%). This demonstrates that inter-rater reliability for determining closure patterns from nasopharyngoscopy is good; however, ratings using MRI was less reliable at determining closure patterns. It is likely that future improvements in dynamic imaging with MRI to enable 3D visualizations are needed for improved diagnostic accuracy for assessing velopharyngeal closure patterns.

Detailed magnetic resonance imaging features of a case series of primary gliosarcoma.

Objective We aimed to characterise the magnetic resonance imaging (MRI) features of a case series of primary gliosarcoma, with the inclusion of diffusion-weighted imaging and perfusion imaging with dynamic susceptibility contrast MRI. Materials and methods We conducted a retrospective study of cases of primary gliosarcoma from the Pathology Department database from January 2006 to December 2014. Clinical and demographic data were obtained. Two neuroradiologists, blinded to diagnosis, assessed tumour location, signal intensity in T1 and T2-weighted images, pattern of enhancement, diffusion-weighted imaging and dynamic susceptibility contrast MRI studies on preoperative MRI. Results Seventeen patients with primary gliosarcomas had preoperative MRI study: seven men and 10 women, with a mean age of 59 years (range 27-74). All lesions were well demarcated, supratentorial and solitary (frontal n = 5, temporal n = 4, parietal n = 3); 13 tumours abutted the dural surface (8/13 with dural enhancement); T1 and T2-weighted imaging patterns were heterogeneous and the majority of lesions (12/17) showed a rim-like enhancement pattern with focal nodularities/irregular thickness. Restricted diffusion (mean apparent diffusion coefficient values 0.64 × 10-3 mm2/s) in the more solid/thick components was present in eight out of 11 patients with diffusion-weighted imaging study. Dynamic susceptibility contrast MRI study ( n = 8) consistently showed hyperperfusion in non-necrotic/cystic components on relative cerebral volume maps. Conclusions The main distinguishing features of primary gliosarcoma are supratentorial and peripheral location, well-defined boundaries and a rim-like pattern of enhancement with an irregular thick wall. Diffusion-weighted imaging and relative cerebral volume map analysis paralleled primary gliosarcoma with high-grade gliomas, thus proving helpful in differential diagnosis.

Dynamic 3-D MR Visualization and Detection of Upper Airway Obstruction During Sleep Using Region-Growing Segmentation.

We demonstrate a novel and robust approach for visualization of upper airway dynamics and detection of obstructive events from dynamic 3-D magnetic resonance imaging (MRI) scans of the pharyngeal airway. This approach uses 3-D region growing, where the operator selects a region of interest that includes the pharyngeal airway, places two seeds in the patent airway, and determines a threshold for the first frame. This approach required 5 s/frame of CPU time compared to 10 min/frame of operator time for manual segmentation. It compared well with manual segmentation, resulting in Dice Coefficients of 0.84 to 0.94, whereas the Dice Coefficients for two manual segmentations by the same observer were 0.89 to 0.97. It was also able to automatically detect 83% of collapse events. Use of this simple semiautomated segmentation approach improves the workflow of novel dynamic MRI studies of the pharyngeal airway and enables visualization and detection of obstructive events. Obstructive sleep apnea (OSA) is a significant public health issue affecting 4-9% of adults and 2% of children. Recently, 3-D dynamic MRI of the upper airway has been demonstrated during natural sleep, with sufficient spatiotemporal resolution to noninvasively study patterns of airway obstruction in young adults with OSA. This study makes it practical to analyze these long scans and visualize important factors in an MRI sleep study, such as the time, site, and extent of airway collapse.

Usefulness of dynamic contrast-enhanced MRI in the evaluation of the viability of acute scaphoid fracture

To evaluate the usefulness of dynamic gadolinium-enhanced magnetic resonance imaging (MRI) for assessing the viability of the proximal pole of the scaphoid in patients with acute scaphoid fractures. Eighteen consecutive patients with acute scaphoid fracture who underwent dynamic gadolinium-enhanced MRI 7days or less before surgery were prospectively included between August 2011 and December 2012. All patients underwent MR imaging with unenhanced images, enhanced images, and dynamic enhanced images. A radiologist first classified the MRI results as necrotic or viable based on T1- and T2-weighted images only, followed by a second blinded interpretation, this time including analysis of pre- and post-gadolinium administration images and a third blinded interpretation based on the time-intensity curve of the dynamic enhanced study. The standard of reference was the histologic assessment of a cylindrical specimen of the proximal pole obtained during surgery in all patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for unenhanced, enhanced, and dynamic gadolinium-enhanced MRI studies. The sensitivity, specificity, PPV, and NPV were 67, 67, 50, and 80% for unenhanced images, 83, 100, 100, and 92 for enhanced images, and 83, 92, 83, and 92 for dynamic contrast-enhanced images. Our data are consistent with previously reported data supporting contrast-enhanced MRI for assessment of viability, and showing that dynamic imaging with time-intensity curve analysis does not provide additional predictive value over standard delayed enhanced imaging for acute scaphoid fracture.

Image based measurements for evaluation of pelvic organ prolapse

Magnetic resonance imaging (MRI) measurements are essential for the diagnosis of pelvic organ prolapse given the inaccuracy of clinical examination. However, MRI pelvic floor measurements are currently performed manually and can be inconsistent and time-consuming. In this paper, we present a scheme for semi-automatic measurement modeling on MRI based on image segmentation and intersecting point identification methods. The segmentation algorithm is a multi-stage mechanism based on block grouping, support vector machine classification, morphological operation and prior shape information. Block grouping is achieved by classifying blocks as bone or background based on image texture features. The classified blocks are then used to find the initial segmentation by the first phase morphological opening. Prior shape information is incorporated into the initial segmentation to obtain the final segmentation using registration with the similarity type transformation. After segmentation, points of reference that are used for pelvic floor measurements are identified using morphological skeleton operation. The experiments on the MRI images show that the presented scheme can detect the points of reference on the pelvic floor structure to determine the reference lines needed for the assessment of pelvic organ prolapse. This will lead towards more consistent and faster pelvic organ prolapse diagnosis on dynamic MRI studies, and possible screening procedures for predicting predisposition to pelvic organ prolapse by radiologic evaluation of pelvic floor measurements.

Leiomyoma of the nipple diagnosed by MRI

Leiomyoma of the nipple is a rare, benign, non-epithelial tumor that is thought to arise from smooth muscle fibers in the subareolar tissue of the breast. We report an unusual case of leiomyoma of the nipple in a 32-year-old woman in whom the diagnosis was made by ultrasound-guided core needle biopsy. She came to our hospital complaining of a recently enlarged nipple with discharge and erosion in the region of the left nipple-areolar complex. This mass was evaluated by mammography, ultrasonography, and magnetic resonance imaging (MRI). To the best of our knowledge, this is the first case of a leiomyoma of the nipple examined by MRI. MRI showed an oval mass with circumscribed margins that appeared as an intermediate signal intensity on both T1- and T2-weighted images. A dynamic MRI study showed a rim-enhancing oval mass with delayed persistent enhancement. Ultrasound-guided core needle biopsy revealed spindle cell proliferation consistent with leiomyoma of the nipple.

Determination of Metastatic Axillary Lymph Node in Breast Cancer: Differentiation with Dynamic MRI Examination by Signal Intensity-Time Curves

Purpose: We aimed to evaluate the role of dynamic magnetic resonance imaging (MRI) in the detection of axillary lymph node metastasis based on the signal intensity-time curves. Materials and Methods: The data of 120 patients (benign patients, n = 91; malignant patients, n = 29) who underwent dynamic breast MRI were reviewed. The lymph nodes with the strongest criteria for malignancy (morphological-dynamic properties) were included in the analysis. Signal intensity-time curves were plotted by the software. Results: Of 29 patients with breast cancer, axillary lymph nodes were involved in 21 and not involved in the remaining 8. There was no significant difference between benign and malignant cases in terms of the distributions of Type Ia, Type Ib and Type IV curves (p = 0.12), whereas a significant difference was found between benign and malignant cases in terms of the distributions of Type II and III curves (p Conclusion: On dynamic MRI studies, benign and metastatic lymph nodes display different signal intensity-time curves.

McConnell Taping Shifts the Patella Inferiorly in Patients With Patellofemoral Pain: A Dynamic Magnetic Resonance Imaging Study

Patellar taping is widely used clinically to treat patients with patellofemoral pain syndrome (PFPS). Although patellar taping has been demonstrated to reduce patellofemoral pain in patients with PFPS, the kinematic source for this pain reduction has not been identified. The purpose of this study was to quantify the changes in the 6-degrees-of-freedom patellofemoral kinematics due to taping in patients with PFPS. A within-subject design and a sample of convenience were used. Fourteen volunteers (19 knees) who were diagnosed with patellofemoral pain that was present for a year or longer were included. Each knee had to meet at least 1 of the following inclusion criteria: Q-angle of > or =15 degrees, a positive apprehension test, patellar lateral hypermobility (> or =10 mm), or a positive "J sign." Each knee underwent 2 randomly ordered testing conditions (untaped and taped). A full fast-phase contrast (PC) magnetic resonance image set was acquired for each condition while the participants volitionally extended and flexed their knee. Three-dimensional displacements and rotations were calculated through integration of the fast-PC velocity data. Statistical comparisons between baseline patellofemoral kinematics and the change in kinematics due to taping were performed using a 2-tailed paired Student t test. Correlations between baseline patellofemoral kinematics and the change in kinematics due to taping also were quantified. Patellar taping resulted in a significant patellofemoral inferior shift. The strongest correlation existed between the change in lateral-medial displacement with taping and baseline (r=-.60). The inferior shift in patellar displacement with taping partially explains the previously documented decrease in pain due to increases in contact area. The lack of alteration in 5 of the 6 kinematic variables with taping may have been due to the fact that post-taping kinematic alterations are sensitive to the baseline kinematic values.

Small field of view imaging using wavelet encoding with 2 dimensional RF pulses and gradient echo: phantom results

The objective of this work is to propose an imaging sequence based upon the wavelet encoding approach to provide MRI images free from folding artifacts, in the small field of view (FOV) regime, such as dynamic magnetic resonance imaging (MRI) studies. The method consists of using a 2D spatially selective RF excitation pulse inserted into a gradient- echo pulse sequence to excite spins within a determined plane where wavelet encoding is achieved in one direction and slice selection is performed in the second direction. Wavelet encoding allows for spatially localized excitation and consequently restricts the spins excited within a reduced FOV. It consists of varying, according to a predetermined scheme, the width and position of the profile of the so-called fast RF pulse of the 2D RF excitation pulse, to obey wavelet encoding translation and dilation conditions. This sequence is implemented on a 3 Tesla whole body Siemens scanner. Compared to Fourier encoding, the proposed technique tested on phantoms with different shapes and structures, is able to provide gradient-echo reduced FOV images free from aliased signals. Wavelet encoding is suitable for small FOV imaging in dynamic MRI studies.

Magnetic Resonance Assessment of Response to Therapy: Tumor Change Measurement, Truth Data and Error Sources

This article describes methods and issues that are specific to the assessment of change in tumor characteristics as measured using quantitative magnetic resonance (MR) techniques and how this relates to the establishment of quantitative MR imaging (MRI) biomarkers of patient response to therapy. The initial focus is on the various sources of bias and variance in the measurement of microvascular parameters and diffusion parameters as such parameters are being used relatively commonly as secondary or exploratory end points in current phase 1/2 clinical trails of conventional and targeted therapies. Several ongoing initiatives that seek to identify the magnitude of some of the sources of measurement variations are then discussed. Finally, resources being made available through the National Cancer Institute Reference Image Database to Evaluate Response (RIDER) project that might be of use in investigations of quantitative MRI biomarker change analysis are described. These resources include 1) data from phantom-based assessment of system response, including short-term (1 hour) and moderate-term (1 week) contrast response and relaxation time measurement, 2) data obtained from repeated dynamic contrast agent-enhanced MRI studies in intracranial tumors, and 3) data obtained from repeated diffusion MRI studies in both breast and brain. A concluding section briefly discusses issues that must be addressed to allow the transition of MR-based imaging biomarker measures from their current role as secondary/exploratory end points in clinical trials to primary/surrogate markers of response and, ultimately, in clinical application.

Vocal Tract in Female Registers—A Dynamic Real-Time MRI Study

The area of vocal registers is still unclarified. In a previous investigation, dynamic real-time magnetic resonance imaging (MRI), which is able to produce up to 10 frames per second, was successfully applied for examinations of vocal tract modifications in register transitions in male singers. In the present study, the same MRI technique was used to study vocal tract shapes during four professional young sopranos' lower and upper register transitions. The subjects were asked to sing a scale on the vowel /a/ across their transitions. The transitions were acoustically identified by four raters. In neither of these transitions, clear vocal tract changes could be ascertained. However, substantial changes, that is, widening of the lips, opening of the jaw, elevation of the tongue dorsum, and continuous widening of the pharynx, were observed when the singers reached fundamental frequencies that were close to the frequency of the first formant of the vowel sung. These findings suggest that in these subjects register transition was not primarily the result of modifications of the vocal tract.

Lung Motion and Volume Measurement by Dynamic 3D MRI Using a 128-Channel Receiver Coil

The authors present their initial experience using a 3-T whole-body scanner equipped with a 128-channel coil applied to lung motion assessment. Recent improvements in fast magnetic resonance imaging (MRI) technology have enabled several trials of free-breathing three-dimensional (3D) imaging of the lung. A large number of image frames necessarily increases the difficulty of image analysis and therefore warrants automatic image processing. However, the intensity homogeneities of images of prior dynamic 3D lung MRI studies have been insufficient to use such methods. In this study, initial data were obtained at 3 T with a 128-channel coil that demonstrate the feasibility of acquiring multiple sets of 3D pulmonary scans during free breathing and that have sufficient quality to be amenable to automatic segmentation. Dynamic 3D images of the lungs of two volunteers were acquired with acquisition times of 0.62 to 0.76 frames/s and an image matrix of 128 x 128, with 24 to 30 slice encodings. The volunteers were instructed to take shallow and deep breaths during the scans. The variation of lung volume was measured from the segmented images. Dynamic 3D images were successfully acquired for both respiratory conditions for each subject. The images showed whole-lung motion, including lifting of the chest wall and the displacement of the diaphragm, with sufficient contrast to distinguish these structures from adjacent tissues. The average time to complete segmentation for one 3D image was 4.8 seconds. The tidal volume measured was consistent with known tidal volumes for healthy subjects performing deep-breathing maneuvers. The temporal resolution was insufficient to measure tidal volumes for shallow breathing. This initial experience with a 3-T whole-body scanner and a 128-channel coil showed that the scanner and imaging protocol provided dynamic 3D images with spatial and temporal resolution sufficient to delineate the diaphragmatic domes and chest wall during active breathing. In addition, the intensity homogeneities and signal-to-noise ratio were adequate to perform automatic segmentation.

Pilomatricoma

Pilomatricoma is an asymptomatic, slowly growing, benign skin tumor that is typically located in the regions of head and neck. We present 1 case of pilomatricoma studied with dynamic magnetic resonance imaging and bone scintigraphy. Our case revealed late enhancement in the dynamic magnetic resonance imaging study that is a common pattern more in a benign soft tissue tumor and caused dramatic uptake in the bone scintigraphy. These findings are not ever reported in published articles. Surgical excision of the lesions was performed, and the pathological evaluation revealed a pilomatricoma.