Specific Magnetic Resonance Imaging Sequences Research Articles

Magnetic resonance imaging in pediatric epilepsy patients: two different protocols

AimThe magnetic resonance imaging (MRI) has a crucial position in the diagnostic routine of epilepsy patients. The aim of this study is to demonstrate, in pediatric epilepsy patients, the greater effectiveness of the HARNESS-MRI Protocol compared to the Standard 3 mm-MRI Protocol, in terms of acquisition times.Materials and methodsIn this study, 30 pediatric patients (17 males and 13 females) with clinical suspicion of epilepsy who underwent MRI (Achieva Philips 1.5 T) at the University Clinics of Sassari in the years 2021–2023 were evaluated. The duration of both MRI protocols was analyzed, and they were composed of specific MRI sequences characterized by three-dimensional (3D) volumetric and isotropic voxels, using the 1.5/3 Tesla (T) MRI scanners. If present, the epileptogenic focus has been highlighted.ResultsThe statistical analysis demonstrates a different time and standard deviation (sd) between the two study protocols: 36.93 ± 16.46 sd for “Standard 3 mm-MRI Protocol” and 29.93 ± 10.41 sd for the “HARNESS-MRI Protocol”. This analysis showed a difference between the acquisition times of 7 min in favor of the HARNESS-MRI Protocol, with the same diagnostic accuracy.ConclusionThe HARNESS-MRI Protocol would guarantee a greater patient comfort and the possibility of performing more MRI with reduced healthcare costs. Furthermore, the routine use of the same protocol and MRI sequences could guarantee better standardization and homogeneity of diagnostic procedures and the follow-up of epilepsy pediatric patients.

The design of a sample rapid magnetic resonance imaging (MRI) acquisition protocol supporting assessment of multiple articular tissues and pathologies in knee osteoarthritis

ObjectiveThis expert opinion paper proposes a design for a state-of-the-art magnetic resonance image (MRI) acquisition protocol for knee osteoarthritis clinical trials in early and advanced disease. Semi-quantitative and quantitative imaging endpoints are supported, partly amendable to automated analysis. Several (peri-) articular tissues and pathologies are covered, including synovitis. MethodA PubMed literature search was conducted, with focus on the past 5 years. Further, osteoarthritis imaging experts provided input. Specific MRI sequences, orientations, spatial resolutions and parameter settings were identified to align with study goals. We strived for implementation on standard clinical scanner hardware, with a net acquisition time ≤30 ​min. ResultsShort- and long-term longitudinal MRIs should be obtained at ≥1.5T, if possible without hardware changes during the study. We suggest a series of gradient- and spin-echo-sequences, supporting MOAKS, quantitative analysis of cartilage morphology and T2, and non-contrast-enhanced depiction of synovitis. These sequences should be properly aligned and positioned using localizer images. One of the sequences may be repeated in each participant (re-test), optimally at baseline and follow-up, to estimate within-study precision. All images should be checked for quality and protocol-adherence as soon as possible after acquisition. Alternative approaches are suggested that expand on the structural endpoints presented. ConclusionsWe aim to bridge the gap between technical MRI acquisition guides and the wealth of imaging literature, proposing a balance between image acquisition efficiency (time), safety, and technical/methodological diversity. This approach may entertain scientific innovation on tissue structure and composition assessment in clinical trials on disease modification of knee osteoarthritis.

The Impact of Body Fat Distribution on COVID-19 Vaccine Response: An MRI-Based Study

Objective: Subcutaneous and visceral adipose tissue have distinct physiological roles. The correlation between the amount of visceral tissue and the immunity response following vaccination remains unclear, despite its known effects on immunity. The purpose of this study is to examine the relationship between SARS-CoV-2 IgG antibody levels after vaccination and body fat tissue values measured using a specialized software on specific magnetic resonance imaging sequences.
 Methods: After ethics committee approval, prospectively 60 volunteers (27 males, 33 females; median age of 33 years) were vaccinated with inactivated SARS-CoV-2 vaccine and tested for IgG levels. Abdominal MRI was performed to measure subcutaneous and visceral fat tissue areas using a semiautomatic application.
 Results: The median value of IgG antibody titers after vaccination was 1039 (113 – 6613). Median subcutaneous adipose tissue(cm2), visceral adipose tissue (cm2), SAT index (SATI) (cm2/m2), VAT index (VATI) (cm2/m2), total fat area (TFA) (cm2), and SAT/VAT (cm2) were 178.5 (38.1-552.5), 51.5 (7.1-273.2), 61.4 (14.3-213.1), 19.1 (2.7-90.6), 251.3 (45.3-683.2), and 3.3 (0.4-12.3) respectively. There was no significant
 correlation between the adipose tissue measurements and antibody titers (p>.05).
 Conclusion: This study demonstrated that automated software can efficiently and accurately evaluate body fat distribution using MRI. However, the results showed no significant association between fat distribution and the immunization response to the SARS-CoV-2 vaccine.

Congruence and incongruence on the radiological and functional examination of inner ear hemorrhage

Background Inner ear hemorrhage (IEH) is an increasingly recognized cochlear lesion that can cause sensorineural hearing loss (SNHL). Magnetic resonance imaging (MRI) is known to be the best imaging modality for clarifying the causes of SNHL and providing images that point to those causes. Aims Evaluate the lesional patterns in patients with presumed Inner ear hemorrhage (IEH) from radiological and functional aspects. Material and Methods We retrospectively reviewed 10 patients performed in our institution from 2014 to 2020, with suspected labyrinthine hemorrhage based on radiological and functional examination. Results We included 8 patients with IEH and sensorineural hearing loss (SNHL). The median age was 55 years (range: 3 months − 78 years). The results from the MRI and functional tests were compared for each end-organ. Only three cases (37.5%) showed a correlation between signal abnormalities and dysfunction in the labyrinthine apparatus. Conclusions In patients with SNHL inner ear hemorrhage needs to be ruled out in the differential diagnosis, so specific MRI sequences should be requested. It represents a way to a better understanding of the disorder and the variety of findings claim for a complete auditory and vestibular testing.

Different patterns of Locus Coeruleus MRI alteration in Alzheimer's and Dementia with Lewy bodies.

the integrity of Locus Coeruleus can be evaluated in vivo using specific Magnetic Resonance Imaging sequences. While this nucleus has been shown to be degenerated both in post-mortem and in vivo studies in Alzheimer's Disease, for other neurodegenerative dementias such as Dementia with Lewy Bodies this has only been shown ex-vivo. to evaluate the integrity of the Locus Coeruleus through Magnetic Resonance Imaging in patients suffering from Dementia with Lewy Bodies and explore the possible differences with the Locus Coeruleus alterations occurring in Alzheimer's Dementia. eleven patients with Dementia with Lewy Bodies and 35 with Alzheimer's Dementia were recruited and underwent Locus Coeruleus Magnetic Resonance Imaging, along with 52 cognitively intact, age-matched controls. Images were analyzed applying an already developed template-based approach; Locus Coeruleus signal was expressed through the Locus Coeruleus Contrast Ratio parameter, and a locoregional analysis was performed. both groups of patients showed significantly lower values of Locus Coeruleus Contrast Ratio when compared to controls. A different pattern of spatial involvement was found; patients affected by Dementia with Lewy bodies showed global and bilateral involvement of the Locus Coeruleus, whereas the alterations in Alzheimer's Dementia patients were more likely to be localized in the rostral part of the left nucleus. Magnetic Resonance Imaging successfully detects widespread Locus Coeruleus degeneration in patients suffering from Dementia with Lewy Bodies. Further studies, in larger cohorts and in earlier stages of the disease, are needed to better disclose the potential diagnostic and prognostic role of this neuroradiological tool.

1.5 T MRI with a Dedicated Dental Signal-Amplification Coil as Noninvasive, Radiation-Free Alternative to CBCT in Presurgical Implant Planning Procedures.

Cone beam computed tomography (CBCT) is considered both reliable and safe and provides reproducible results in guided dental implant planning procedures. However, it has weaknesses in soft tissue contrast and is associated with radiation exposure. Recent studies showed promising results with magnetic resonance imaging (MRI) as a possible noninvasive, radiation-free, alternative imaging modality for dental indications. The purpose of this study was to evaluate the quality of 1.5 T MRI with a dedicated dental signal-amplification coil in comparison to CBCT for dental implant planning procedures. Sixteen subjects undergoing preoperative MRI (3D HR T1w TSE and 3D HR T1w FFE) and CBCT were included in this prospective study. All imaging data were used for dental implant planning procedures using commercially available software. Two experts scored the planning as "ideal," "improvable," or "unacceptable." Furthermore, quantitative distances according to EuCC recommendations were collected. Finally, discrepancies between CBCT and 3D HR T1w TSE were analyzed. Statistical analysis was performed using the Mann-Whitney U test and analysis of variance (ANOVA). The dental implant planning procedure was technically feasibly using all imaging data. CBCT allowed for "ideal" placement in all cases. Ratings for 3D HR T1w TSE and 3D HR T1w FFE were 81.9%, 18.1%, and 0% and 54.2%, 30.0%, and 15.3% for ideal, improvable, and unacceptable, respectively, identifying 3D HR T1w TSE as superior compared with 3D HR T1w FFE. Head-to-head comparison between CBCT and 3D HR T1w TSE revealed no significant differences regarding the apical position of the implant of 1.2 ± 0.7 mm and 1.3 ± 0.5 mm coronally, respectively (P = .287). The deviation of the planed angle was 3.0 ± 1.2 degrees. In these merged data sets, the distance to the mandibular canal was significantly higher with 1.3 ± 0.8 mm, indicating better utilization of the existing bone. Within the limits of this pilot study, it can be reported that the dental image planning procedure is feasible using 1.5 T MRI with a dedicated dental coil and specific MRI sequences.

Automatic discrimination of different sequences and phases of liver MRI using a dense feature fusion neural network: a preliminary study.

To develop and validate a dense feature fusion neural network (DFuNN) to automatically recognize different sequences and phases of liver magnetic resonance imaging (MRI). In total, 3869 sequences and phases from 384 liver MRI examinations, divided into training/validation (n = 2886 sequences from 287 patients) and test (n = 983 sequences from 97 patients) sets, were used in this retrospective study. Ten unenhanced sequences and enhanced phases were included. Manual sequence recognition, performed by two radiologists (20 and 10years of experience) in a consensus reading, was used as the reference standard. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were calculated to evaluate the performance of the DFuNN on an identical unseen test set. Finally, we evaluated the factors impacting the model precision. A fusion block improved the performance of the DFuNN. DFuNN with a fusion block achieved good recognition performance for both complete and incomplete sequences and phases in the test set. The average sensitivity of recognition performance for complete sequence and phase inputs ranged from 88.06 to 100%, the average specificity ranged from 99.12 to 99.94%, and the median accuracy ranged from 98.02 to 99.95%. The DFuNN prediction accuracy for patients without cirrhosis were significantly higher than those for patients with cirrhosis (P = 0.0153). No significant difference was found in the accuracy across other factors. DFuNN can automatically and accurately identify specific unenhanced MRI sequences and enhanced MRI phases.

A 3D cine-MRI acquisition technique and image analysis framework to quantify bowel motion demonstrated in gynecological cancer patients.

PurposeMagnetic resonance imaging (MRI) is increasingly used in radiation oncology for target delineation and radiotherapy treatment planning, for example, in patients with gynecological cancers. As a consequence of pelvic radiotherapy, a part of the bowel is irradiated, yielding risk of bowel toxicity. Existing dose‐effect models predicting bowel toxicity are inconclusive and bowel motion might be an important confounding factor. The exact motion of the bowel and dosimetric effects of its motion are yet uncharted territories in radiotherapy. In diagnostic radiology methods on the acquisition of dynamic MRI sequences were developed for bowel motility visualization and quantification. Our study aim was to develop an imaging technique based on three‐dimensional (3D) cine‐MRI to visualize and quantify bowel motion and demonstrate it in a cohort of gynecological cancer patients.MethodsWe developed an MRI acquisition suitable for 3D bowel motion quantification, namely a balanced turbo field echo sequence (TE = 1.39 ms, TR = 2.8 ms), acquiring images in 3.7 s (dynamic) with a 1.25 × 1.25 × 2.5 mm3 resolution, yielding a field of view of 200 × 200 × 125 mm3. These MRI bowel motion sequences were acquired in 22 gynecological patients. During a 10‐min scan, 160 dynamics were acquired. Subsequent dynamics were deformably registered using a B‐spline transformation model, resulting in 159 3D deformation vector fields (DVFs) per MRI set. From the 159 DVFs, the average vector length was calculated per voxel to generate bowel motion maps. Quality assurance was performed on all 159 DVFs per MRI, using the Jacobian Determinant and the Harmonic Energy as deformable image registration error metrics. In order to quantify bowel motion, we introduced the concept of cumulative motion–volume histogram (MVH) of the bowel bag volume. Finally, interpatient variation of bowel motion was analyzed using the MVH parameters M10%, M50%, and M90%. The M10%/M50%/M90% represents the minimum bowel motion per frame of 10%/50%/90% of the bowel bag volume.ResultsThe motion maps resulted in a visualization of areas with small and large movements within the bowel bag. After applying quality assurance, the M10%, M50%, and M90% were 4.4 (range 2.2–7.6) mm, 2.2 (range 0.9–4.1) mm, and 0.5 (range 0.2–1.4) mm per frame, on average over all patients, respectively.ConclusionWe have developed a method to visualize and quantify 3D bowel motion with the use of bowel motion specific MRI sequences in 22 gynecological cancer patients. This 3D cine‐MRI‐based quantification tool and the concept of MVHs can be used in further studies to determine the effect of radiotherapy on bowel motion and to find the relation with dose effects to the small bowel. In addition, the developed technique can be a very interesting application for bowel motility assessment in diagnostic radiology.

Lower Locus Coeruleus MRI intensity in patients with late-life major depression.

BackgroundThe locus coeruleus (LC) is the major noradrenergic source in the central nervous system. Structural alterations in the LC contribute to the pathophysiology of different neuropsychiatric disorders, which may increase to a variable extent the likelihood of developing neurodegenerative conditions. The characterization of such alterations may therefore help to predict progression to neurodegenerative disorders. Despite the LC cannot be visualized with conventional magnetic resonance imaging (MRI), specific MRI sequences have been developed to infer its structural integrity.MethodsWe quantified LC signal Contrast Ratios (LCCRs) in late-life major depressive disorder (MDD) (n = 37, 9 with comorbid aMCI), amnestic Mild Cognitive Impairment (aMCI) (n = 21, without comorbid MDD), and healthy controls (HCs) (n = 31), and also assessed the putative modulatory effects of comorbidities and other clinical variables.ResultsLCCRs were lower in MDD compared to aMCI and HCs. While no effects of aMCI comorbidity were observed, lower LCCRs were specifically observed in patients taking serotonin/norepinephrine reuptake inhibitors (SNRIs).ConclusionOur results do not support the hypothesis that lower LCCRs characterize the different clinical groups that may eventually develop a neurodegenerative disorder. Conversely, our results were specifically observed in patients with late-life MDD taking SNRIs. Further research with larger samples is warranted to ascertain whether medication or particular clinical features of patients taking SNRIs are associated with changes in LC neurons.

Elevated Circulating Microparticle Subpopulations in Incidental Cerebral White Matter Hyperintensities: A Multimodal Study.

Asymptomatic (or “silent”) manifestations of cerebral small vessel disease (CSVD) are widely recognized through incidental findings of white matter hyperintensities (WMHs) as a result of magnetic resonance imaging (MRI). This study aims to examine the potential associations of surrogate markers for the evaluation of white matter integrity in CSVD among asymptomatic individuals through a battery of profiling involving QRISK2 cardiocerebrovascular risk prediction, neuroimaging, neurocognitive evaluation, and microparticles (MPs) titers. Sixty asymptomatic subjects (mean age: 39.83 ± 11.50 years) with low to moderate QRISK2 scores were recruited and underwent neurocognitive evaluation for memory and cognitive performance, peripheral venous blood collection for enumeration of selected MPs subpopulations, and 3T MRI brain scan with specific diffusion MRI (dMRI) sequences inclusive of diffusion tensor imaging (DTI). WMHs were detected in 20 subjects (33%). Older subjects (mean age: 46.00 ± 12.00 years) had higher WMHs prevalence, associated with higher QRISK2 score and reduced processing speed. They also had significantly higher mean percentage of platelet (CD62P)- and leukocyte (CD62L)-derived MPs. No association was found between reduced white matter integrity—especially at the left superior longitudinal fasciculus (LSLF)—with age and neurocognitive function; however, LSLF was associated with higher QRISK2 score, total MPs, and CD62L- and endothelial cell-derived MPs (CD146). Therefore, this study establishes these multimodal associations as potential surrogate markers for “silent” CSVD manifestations in the well-characterized cardiocerebrovascular demographic of relatively young, neurologically asymptomatic adults. Furthermore, to the best of our knowledge, this study is the first to exhibit elevated MP counts in asymptomatic CSVD (i.e., CD62P and CD62L), which warrants further delineation.

Differential diagnosis of gallbladder abnormalities : Ultrasound, computed tomography, and magnetic resonance imaging

Due to the high prevalence of clinically suspected cholecystitis or cholecystolithiasis the gallbladder is one of the organs examined the most by imaging. In most clinical settings ultrasound is the primary imaging method because of its wide availability, speed and superior spatial resolution. In cases of ambiguous findings or potential complications computed tomography (CT) and magnetic resonance imaging (MRI) are used. When specific problems arise these imaging modalities may be enhanced by special techniques, e. g. contrast-enhanced ultrasound or dual-energy CT, and specific MRI sequences. Special variants of cholecystitis, such as xanthogranulomatous cholecystitis and adenomyomatosis, may pose aparticularly difficult diagnostic problem as they may resemble other diseases. Sequelae of cholecystolithiasis, such as the Mirizzi syndrome and acute bowel obstruction, may complicate the imaging algorithm as the location and the symptoms shift. Cases of neoplastic diseases of gallbladder cancer and other malignancies require abroad spectrum of imaging modalities. Although the gallbladder can easily be examined with ultrasound, some cases require amore thorough ultrasound examination. In some cases only acombination of multiple imaging modalities yield the diagnosis. Further developments regarding technical issues and the diagnostic algorithm can be expected. Ultrasound is the best first imaging modality. In cases of ambiguous findings or clinical complications CT or MRI are recommended.

Chapter 17 - Other cerebrovascular occlusive disease

In this chapter we review the optimal imaging modalities for subacute and chronic stroke. We discuss the utility of computed tomography (CT) and multimodal CT imaging. Further, we analyze the importance of specific magnetic resonance imaging sequences, such as diffusion-weighted imaging for acute ischemic stroke, T2/fluid-attenuated inversion recovery for subacute and chronic stroke, and susceptibility imaging for detection of intracranial hemorrhages. Different ischemic stroke mechanisms are reviewed, and how these imaging modalities may aid in the determination of such. Further, we analyze how topographic patterns in ischemic stroke may provide important clues to the diagnosis, in addition to the temporal evolution of the stroke. Lastly, specific cerebrovascular occlusive diseases are reviewed, with emphasis on the optimal imaging modalities and their findings in each condition.

Conversion paralysis after cervical spine arthroplasty: A case report and literature review

We report a case of conversion paralysis after cervical spine arthroplasty performed in a 45-year-old woman to treat cervico-brachial neuralgia due to a left-sided C6–C7 disc herniation. Upon awakening from the anaesthesia, she had left hemiplegia sparing the face, with normal sensory function. Magnetic resonance imaging (MRI) of the brain ruled out a stroke. MRI of the spinal cord showed artefacts from the cobalt-chrome prosthesis that precluded confident elimination of mechanical spinal cord compression. Surgery performed on the same day to substitute a cage for the prosthesis ruled out spinal cord compression, while eliminating the source of MRI artefacts. Findings were normal from follow-up MRI scans 1 and 15days later, as well as from neurophysiological testing (electromyogram and motor evoked potentials). The deficit resolved fully within the next 4days. A psychological assessment revealed emotional distress related to an ongoing divorce. The most likely diagnosis was conversion paralysis. Surgeons should be aware that conversion disorder might develop after a procedure on the spine, although the risk of litigation requires re-operation. Familiarity with specific MRI sequences that minimise artefacts can be valuable. A preoperative psychological assessment might improve the detection of patients at high risk for conversion disorder.

Hybrid PET/MRI as a tool to detect brown adipose tissue: Proof of principle

The purpose of this study was to assess the performance of (18)F-FDG hybrid PET/MRI to detect and localise the presence of metabolically active brown adipose tissue (BAT). We retrospectively analyzed 197 consecutive (18)F-flurodeoxyglucose ((18)F-FDG) positron-emission tomographic (PET) and magnetic resonance imaging (MRI) images performed with a hybrid whole-body PET-MRI tomography in 192 patients. These patients were originally investigated mainly for oncological staging, in the absence of a cooling protocol. The presence of BAT was defined as a soft tissue structure that was larger than 4mm in diameter, had the characteristics of fat tissue on MRI and had a maximal standardised uptake value (SUV) of (18)F-FDG of at least 2.0. No specific MRI sequences for BAT detection were acquired. PET/MRI identified the presence of metabolically active BAT in 5 out of 192 patients (2.6%). BAT positive subjects were all female, significantly younger and with significantly lower body weight than BAT negative subjects. Whole body hybrid PET/MRI allowed for the identification of BAT, with a low prevalence, comparable to previous retrospective PET/CT studies realised in the absence of a cooling protocol. The main advantages of the PET/MRI hybrid technique, as compared with PET/CT, includes a lower radiation burden, and the possibility to combine a multiparameter fat characterization by dedicated MRI sequences. Hybrid PET/MRI might represent the ideal tool for BAT evaluation.

Pituitary stalk thickening on MRI: when is the best time to re-scan and how long should we continue re-scanning for?

Magnetic resonance imaging (MRI) has proved to be an essential tool in the assessment of pituitary stalk lesions including lymphocytic infundibulo-hypophysitis, Langerhans cell histiocytosis (LCH), germ cell tumours, nongerminomatous germ cell tumours, pituicytomas and other tumours, metastases from lymphoma or breast cancer, Wegener's hypophysitis, neurosarcoidosis and inflammatory infiltrations by infectious diseases. The diagnosis of lesions determining pituitary stalk thickness is challenging, and the identification of the underlying condition may require a long-term follow-up. Thus, clinicians should readily recognize that, when the diagnosis of central diabetes insipidus has been established, specific MRI sequences should be used in the assessment of the hypothalamic-pituitary region, and whole-brain evaluation is recommended. For clinical practice, a timely diagnosis is advisable to avoid central nervous system damage, pituitary defects and the risk of dissemination of germ cell tumours or organ involvement by LCH. Proper aetiological diagnosis can be achieved via a series of steps that start with careful observation of several neuroimaging predictors and endocrine dysfunction and then progress to more sophisticated and advanced imaging techniques.

Chapter 17 - Current and future diagnostic tools for traumatic brain injury: CT, conventional MRI, and diffusion tensor imaging

Brain imaging plays a key role in the assessment of traumatic brain injury. In this review, we present our perspectives on the use of computed tomography (CT), conventional magnetic resonance imaging (MRI), and newer advanced modalities such as diffusion tensor imaging. Specifically, we address assessment for immediately life-threatening intracranial lesions (noncontrast head CT), assessment of progression of intracranial lesions (noncontrast head CT), documenting intracranial abnormalities for medicolegal reasons (conventional MRI with blood-sensitive sequences), presurgical planning for post-traumatic epilepsy (high spatial resolution conventional MRI), early prognostic decision making (conventional MRI with diffusion-weighted imaging), prognostic assessment for rehabilitative planning (conventional MRI and possibly diffusion tensor imaging in the future), stratification of subjects and pharmacodynamic tracking of targeted therapies in clinical trials (specific MRI sequences or positron emission tomography (PET) ligands, e.g., diffusion tensor imaging for traumatic axonal injury). We would like to emphasize that all of these methods, especially the newer research approaches, require careful radiologic-pathologic validation for optimal interpretation. We have taken this approach in a mouse model of pericontusional traumatic axonal injury. We found that the extent of reduction in the diffusion tensor imaging parameter relative anisotropy directly correlated with the number of amyloid precursor protein (APP)-stained axonal varicosities (r(2)=0.81, p<0.0001, n=20 injured mice). Interestingly, however, the least severe contusional injuries did not result in APP-stained axonal varicosities, but did cause reduction in relative anisotropy. Clearly, both the imaging assessments and the pathologic assessments will require iterative refinement.

Olfactory dysfunction in children with Kallmann syndrome: relation of smell tests with brain magnetic resonance imaging.

Kallmann syndrome (KS) is a genetic disorder with the distinctive features of hyposmia or anosmia and hypogonadotropic hypogonadism. Though hyposmia/anosmia can be evaluated by both objective and subjective smell tests, there is no study comparing these two methods in KS. The aim of the present case series was to discuss the results of objective and subjective smell tests and compare them to volumetric magnetic resonance imaging (MRI). A total of six adolescent males (aged between 14-18 years) with KS were examined by objective and subjective olfactometry to test smell function and by specific MRI sequences to measure the olfactory bulbs. The objective smell test showed anosmia in all six of the patients. However, the subjective test revealed anosmia in five patients and hyposmia in one patient. Brain MRI showed olfactory bulb aplasia in all six cases. MRI provides robust evaluation of the olfactory bulb volume. Our data show excellent compatibility between the results obtained via objective olfactometry and those obtained by measuring olfactory bulb volume as determined by MRI and therefore demonstrate that objective olfactometry remains a highly reliable test. Furthermore, although the number of subjects studied was small, these data also suggest that cheaper and more easily available subjective tests could be used in preference to the more expensive as well as labor-intensive and time-consuming objective smell tests. In the event of doubts as to the validity of the subjective tests, the objective olfactometry tests can confirm the diagnosis. The bulb volumetric MRI may be also used in difficult cases.

Magnetic resonance imaging, computed tomography, and gross anatomy of the canine tarsus.

To describe the normal anatomy of the soft tissues of the canine tarsus as identified on computed tomography (CT) and magnetic resonance imaging (MRI) and to evaluate specific MRI sequences and planes for observing structures of diagnostic interest. Prospective descriptive study. Canine cadavers (n = 3). A frozen cadaver pelvic limb was used to trial multiple MRI sequences using a 1.5 T superconducting magnet and preferred sequences were selected. Radiographs of 6 canine cadaver pelvic limbs confirmed the tarsi were radiographically normal. A 16-slice CT scanner was used to obtain 1 mm contiguous slices through the tarsi. T1-weighted, proton density with fat suppression (PD FS) and T2-weighted MRI sequences were obtained in the sagittal plane, T1-weighted, and PD FS sequences in the dorsal plane and PD FS sequences in the transverse plane. The limbs were frozen for one month and sliced into 4-5 mm thick frozen sections. Anatomic sections were photographed and visually correlated to CT and MR images. Most soft tissue structures were easiest to identify on the transverse MRI sections with cross reference to either the sagittal or dorsal plane. Bony structures were easily identified on all CT, MR, and gross sections. The anatomy of the canine tarsus can be readily identified on MR imaging.

Is Preoperative Detection of Neurovascular Conflict in Cranial Nerves Neuralgia Improving Clinical Results

s was already said in a previous comment on the efficacy of microvascular decompression in cases of trigeminal A neuralgia (TN) without any evidence of vascular conflict, the etiology of TN is far from established. Concerning glossopharyngeal neuralgia, the pathophysiologic hypothesis is the same as TN, although the offending vessel usually is easier to detect even without specific magnetic resonance imaging sequences because of the different diameter of the arteries involved.

Fetal MRI

Fetal magnetic resonance imaging (MRI) is used with increasing frequency as a complementary imaging modality to ultrasound (US) in prenatal diagnosis. Fetal MRI displays the fetal, uterine, and extrauterine anatomy in ways that allow confirmation of normal anatomy and the diagnosis of pathological entities that were formerly very difficult to detect prenatally. Comparison of US views with standard orthogonal plane MR images reinforces the understanding of fetal anatomy as visualized with US. Technological advances in US equipment have allowed the recent description of subtle fetal anatomical structures. Similarly, knowledge of the MRI appearances of pathological conditions has opened opportunities for the sonographic diagnosis of entities such as brainstem malformations and alterations in the normal transient laminar pattern that occur during development of the fetal cerebrum. Fetal MRI can confirm suspicious US findings and thus add confidence in a particular prenatal diagnosis before performing invasive and interventional procedures. Specific MRI sequences can be used to add information about the chemical composition of fetal structures, such as fat, blood, and meconium. Dynamic MRI sequences have increased understanding of gestational age-dependent behavior, and assist the sonographer in assessment of fetal structural anomalies that cause abnormal movement and behavior. The technological ability of US to demonstrate very small structures complements the lower resolution of fetal MR images, whereas the ability of MR to visualize the whole fetus improves the limited views necessitated by US. Therefore, both US and fetal MRI have complementary strengths and weaknesses that can be used to full advantage in prenatal diagnosis.