Prolonged T2 Research Articles

Osteomyelitis of the Fifth Toe after Human Bite

Human bite wounds are the third leading cause of bite wounds seen in the emergency departments. Osteomyelitis due to animal bite is well known. However there are very few reports of osteomyelitis secondary to human bite. We present a case of osteomyelitis of the fifth toe due to a human bite. A 13 year old previously healthy Male developed severe pain, redness and swelling with oozing from the wound, 2 days after sustaining a human bite to the right foot. The Magnetic Resonance Imaging (MRI) showed a mild T2 prolongation and enhancement within the proximal phalanx of the fifth digit consistent with osteomyelitis. He was treated for 4 weeks: Ampicillin/Sulbactam for 5 days followed by 11 days of Amoxicillin/Clavulanic and Clindamycin for 25 days. Human bite wounds are a source of serious morbidity with hand and foot wounds due to higher risk of infection. The oral cavity harbors more than 300 different bacterial species. The most common bacteria isolated from bite wounds are Streptococcus sp., Staphylococcal epidermis and Staphylococcus aureus. Anaerobes such as Eikenella, Fusobacterium, Peptostreptococcus, Prevotella and Porphyromonas species are also common. The teeth can cause a deep laceration implanting oral and skin organisms into the joint capsules causing septic arthritis or osteomyelitis with signs and symptoms appearing within 24 to 72 hours. The absence of fever or laboratory evidence of serious bacterial infection in our patient is due to non-hematogenous, contiguous nature of spread of infection. Without imaging by MRI, osteomyelitis would have been missed in this case. Though rare, human bites to the distal extremities should be suspected and assessed for underlying osteomyelitis using MRI to guide appropriate length of antibiotic treatment.

New Findings, Classification and Long-Term Follow-Up Study Based on MRI Characterization of Brainstem Encephalitis Induced by Enterovirus 71.

BackgroundTo report the diversity of MRI features of brainstem encephalitis (BE) induced by Enterovirus 71. This is supported by implementation and testing of our new classification scheme in order to improve the diagnostic level on this specific disease.MethodsNeuroimaging of 91 pediatric patients who got EV71 related BE were hospitalized between March, 2010 to October, 2012, were analyzed retrospectively. All patients underwent pre- and post-contrast MRI scan. Thereafter, 31 patients were randomly called back for follow-up MRI study during December 2013 to August 2014. The MRI signal patterns of BE primary lesion were analyzed and classified according to MR signal alteration at various disease stages. Findings in fatal and non-fatal cases were compared, and according to the MRI scan time point during the course of this disease, the patients’ conditions were classified as 1) acute stage, 2) convalescence stage, 3) post mortem stage, and 4) long term follow-up study.Results103 patients were identified. 11 patients did not undergo MRI, as they died within 48 hours. One patient died on 14th day without MR imaging. 2 patients had postmortem MRI. Medical records and imaging were reviewed in the 91 patients, aged 4 months to 12 years, and two cadavers who have had MRI scan. At acute stage: the most frequent pattern (40 patients) was foci of prolonged T1 and T2 signal, with (15) or without (25) contrast enhancement. We observed a novel pattern in 4 patients having foci of low signal intensity on T2WI, with contrast enhancement. Another pattern in 10 patients having foci of contrast enhancement without abnormalities in T1WI or T2WI weighted images. Based on 2 cases, the entire medulla and pons had prolonged T1 and T2 signal, and 2 of our postmortem cases demonstrated the same pattern. At convalescence stage, the pattern observed in 4 patients was foci of prolonged T1 and T2 signal without contrast enhancement. Follow-up MR study of 31 cases showed normal in 26 cases, and demonstrated foci of prolonged T1 and T2 signal with hyper-intensity on FLAIR in 3 cases, or of prolonged T1 and T2 signal with hypo-intensity on FLAIR in 2 cases. Most importantly, MR findings of each case were thoroughly investigated and classified according to phases and MRI signal alteration.ConclusionsThis study has provided enhanced and useful information for the MRI features of BE induced by EV71, apart from common practice established by previous reports. In addition, a classification scheme that summarizes all types of features based on the MRI signal at the four different stages of the disease would be helpful to improve the diagnostic level.

Quantitative Liver Function Analysis: Volumetric T1 Mapping with Fast Multisection B1 Inhomogeneity Correction in Hepatocyte-specific Contrast-enhanced Liver MR Imaging.

Purpose To determine whether B1 inhomogeneity-corrected volumetric T1 maps of gadoxetic acid-enhanced liver magnetic resonance (MR) imaging are able to demonstrate global liver function and functional heterogeneity in patients with cirrhosis and to investigate their relationship with the development of hepatic insufficiency and decompensation. Materials and Methods This institutional review board-approved retrospective study with waiver of informed consent included 234 consecutive patients who underwent gadoxetic acid-enhanced liver MR imaging, including B1 inhomogeneity-corrected volumetric T1 mapping. For all patients, T1 relaxation times of the liver and liver volumes were measured on T1 maps. Liver T1 and functional liver volume-to-weight ratio (liver volume divided by liver T1 and the patient's weight) were compared between Child-Pugh class A and class B cirrhosis. Associations between serum markers, MR parameters, hepatic insufficiency, and decompensation were investigated by using Cox proportional hazards analysis. Results Patients with Child-Pugh class B disease showed significantly longer liver T1 (548.2 msec ± 257.7 vs 372.2 msec ± 77.5, P < .0001) and lower kurtosis of liver T1 (29.1 ± 39.6 vs 43.9 ± 64.9, P = .016) than patients with Child-Pugh class A disease. Prolonged liver T1 (≥462 msec) (hazard ratio [HR], 5.9; 95% confidence interval [CI]: 1.1, 62.8) and an albumin level of less than 3.5 g/dL (HR, 20.7; 95% CI: 3.9, 221.9) were independently associated with the development of hepatic insufficiency. Functional liver volume-to-weight ratio was associated with the development of hepatic decompensation in patients with Child-Pugh class A disease (HR, 0.03; 95% CI: 0.004, 0.23). Conclusion B1 inhomogeneity-corrected volumetric T1 mapping provided information on global liver function and demonstrated functional heterogeneity. In addition, prolonged liver T1 (≥462 msec) was associated with the development of hepatic insufficiency, and functional liver volume-to-weight ratio was negatively related with the development of decompensation in compensated cirrhosis. © RSNA, 2016 Online supplemental material is available for this article.

Pancreatic tumors in children and young adults with tuberous sclerosis complex.

Pancreatic neuroendocrine tumors are not included in the diagnostic criteria for tuberous sclerosis complex, although an association has been described. To investigate the association of pancreatic neuroendocrine tumor in children and young adults with tuberous sclerosis complex and define MRI characteristics of the tumor. We retrospectively evaluated the abdominal MRI scans of 55 children and young adults with tuberous sclerosis complex for the presence of a pancreatic mass. The scans were performed over a period of 7years to monitor renal pathology. We obtained each patient's clinical history and treatment protocol from the hospital's electronic medical records. A solid pancreatic mass was identified in 5/55 (9%, 95% confidence interval [CI] 3-20%) patients (4 male) with a mean age of 12.6years. Four of the lesions were located in the pancreatic tail and one in the pancreatic body. All of the lesions were solid, ovoid and well demarcated, with a mean diameter of 3.1cm. The masses uniformly demonstrated T1 and T2 prolongation, but their diffusion behavior and post-contrast enhancement varied. The two surgically resected lesions were synaptophysin (+) non-functional pancreatic neuroendocrine tumors on pathology. Two of the patients who did not have surgery were treated with everolimus; one of the lesions has shown interval decrease in size and the other has remained stable. Pancreatic tumor is relatively common in children and young adults with tuberous sclerosis complex.

Feasibility of fat fraction quantification by measuring J-coupling related signal modulation in multi echo fast spin echo sequences

Introduction Echo spacing in Fast Spin Echo techniques can affect signal intensity mainly of fatty tissue and is presented as effectively prolonged T2 relaxation time (magnetic fat liquefaction). Purpose The aim of this study is to measure signal intensity in multi echo Fast Spin Echo techniques with variable echo spacing in order to examine the feasibility of fat quantification from J-coupling related signal modulation. T2 maps were calculated from all different acquisition schemes. Materials and methods A phantom containing porcine fat, vegetable oils, gadolinium doped agarose gels that mimic fat magnetic relaxation properties, double distilled water at controlled temperature of 36–38 °C was scanned at 1.5 T utilizing a single slice multi echo SE technique with equidistant echoes of variable TE intervals (6.7–40 ms). Results Fat signal modulation as a function of echo spacing varied significantly between short and long echo spacing acquisitions (28.97–56.26%) and this dependence could be approximated by a linear sequence ( Δ S fat = S short ESP - S long ESP = 3.38*n*TE + 27.18, residual 7,88 for n ranging from 1 to 12) for a wide range of routinely used TEs in clinical practice (13.4–160.8 ms) while effect on water was minimal ( Δ S water = 22.11%, SD for same TE range: 0.53). Difference of calculated T2 relaxation times between sequences with different echo spacing ranged from 9.5 to 35%. Conclusion Echo spacing in MESE sequences may serve as a metric of signal manipulation and fat quantification. Bright fat sequences should be avoided for T2 relaxation parametric maps.

Chemical exchange saturation transfer of the cervical spinal cord at 7 T.

High-magnetic-field (7 T) chemical exchange saturation transfer (CEST) MRI provides information on the tissue biochemical environment. Multiple sclerosis (MS) affects the entire central nervous system, including the spinal cord. Optimal CEST saturation parameters found via simulation were implemented for CEST MRI in 10 healthy controls and 10 patients with MS, and the results were examined using traditional asymmetry analysis and a Lorentzian fitting method. In addition, T1 - and T2 *-weighted images were acquired for lesion localization and the transmitted B1 (+) field was evaluated to guide imaging parameters. Distinct spectral features for all tissue types studied were found both up- and downfield from the water resonance. The z spectra in healthy subjects had the expected z spectral shape with CEST effects apparent from 2.0 to 4.5 ppm. The z spectra from patients with MS demonstrated deviations from this expected normal shape, indicating this method's sensitivity to known pathology as well as to tissues appearing normal on conventional MRI. Examination of the calculated CESTasym revealed increased asymmetry around the amide proton resonance (Δω = 3.5 ppm), but it was apparent that this measure is complicated by detail in the CEST spectrum upfield from water, which is expected to result from the nuclear Overhauser effect. The z spectra upfield (negative ppm range) were also distinct between healthy and diseased tissue, and could not be ignored, particularly when considering the conventional asymmetry analysis used to quantify the CEST effect. For all frequencies greater than +1 ppm, the Lorentzian differences (and z spectra) for lesions and normal-appearing white matter were distinct from those for healthy white matter. The increased frequency separation and signal-to-noise ratio, in concert with prolonged T1 at 7 T, resulted in signal enhancements necessary to detect subtle tissue changes not possible at lower field strengths. This study presents CEST imaging metrics that may be sensitive to the extensive and temporally varying biochemical neuropathology of MS in the spinal cord. Copyright © 2016 John Wiley & Sons, Ltd.

Quantitative T2 mapping of white matter: applications for ageing and cognitive decline

In MRI, the coherence lifetime T2 is sensitive to the magnetic environment imposed by tissue microstructure and biochemistry in vivo. Here we explore the possibility that the use of T2 relaxometry may provide information complementary to that provided by diffusion tensor imaging (DTI) in ageing of healthy controls (HC), Alzheimer’s disease (AD) and mild cognitive impairment (MCI). T2 and diffusion MRI metrics were quantified in HC and patients with MCI and mild AD using multi-echo MRI and DTI. We used tract-based spatial statistics (TBSS) to evaluate quantitative MRI parameters in white matter (WM). A prolonged T2 in WM was associated with AD, and able to distinguish AD from MCI, and AD from HC. Shorter WM T2 was associated with better cognition and younger age in general. In no case was a reduction in T2 associated with poorer cognition. We also applied principal component analysis, showing that WM volume changes independently of T2, MRI diffusion indices and cognitive performance indices. Our data add to the evidence that age-related and AD-related decline in cognition is in part attributable to WM tissue state, and much less to WM quantity. These observations suggest that WM is involved in AD pathology, and that T2 relaxometry is a potential imaging modality for detecting and characterising WM in cognitive decline and dementia.

T2 relaxometry improves detection of non-sclerotic epileptogenic hippocampus

ObjectThe use of T2 relaxometry was investigated to detect non-sclerotic epileptogenic abnormality of the hippocampus in presurgical evaluation of temporal lobe epilepsy (TLE). MethodsThis prospective study included 30 patients who underwent hippocampectomy as part of surgical treatment of refractory TLE. Ten patients had structural epileptogenic lesions in the extra-hippocampal temporal lobe. Twelve patients underwent intracranial electroencephalography (iEEG) study before surgery. Visual assessment of atrophy and increased T2 signal intensity, volumetry, and T2 relaxometry of hippocampus were performed pre-operatively using 3T magnetic resonance imaging, and compared with the neuropathological findings and iEEG findings. Magnetic resonance imaging of 30 age- and sex-matched healthy controls was used to establish normal values, which were defined as z score within 2. ResultsVisual assessment, volumetry, and T2 relaxometry detected hippocampal abnormalities on the surgical side in 16 (53%), 16 (53%), and 26 (87%) patients, respectively. Hippocampal volume loss was always associated with prolonged T2 relaxation time, and supported by histopathological diagnosis of HS in all cases except one. Hippocampal abnormality was detected only by T2 relaxometry in nine patients (30%). Pathological diagnosis of these cases included mild HS in one, microdysgenesis in one, and granule cell pathology in three. Four patients with normal hippocampal volume and T2 relaxation time had no HS or granule cell pathology. Prolonged T2 relaxation time was associated with medial temporal seizure onset in iEEG (p<0.05). ConclusionsT2 relaxometry improves the detection of non-sclerotic epileptogenic abnormality of the hippocampus.

Quantitative evaluation of cerebral white matter in patients with multiple sclerosis using multicomponent T2 mapping

Objects: A standard magnetic resonance imaging (MRI) investigation of white matter (WM) areas with visible or expected pathology does not explain satisfactorily the relation between pathology and clinical outcome. Therefore, we focused on multicomponent T2 mapping of WM with the intention to characterize the WM, including normal-appearing white matter that has normal and prolonged T2 and lesions, including degenerated tissue.Materials and Methods: Twenty-nine patients with clinically diagnosed MS and 27 healthy controls underwent MRI examination. T2 mapping of the WM across the two whole MRI slices was carried out. The relative abundance of biologically relevant T2 regions was correlated with age and the expanded disability status scale (EDSS).Results: The relative abundance of the T2 values of water trapped in myelin increased with age in both healthy subjects (p < 0.05) and MS patients (p < 0.05). The relative abundance of intermediate T2 assigned to intra- and extracellular water decreased with age in both groups (p < 0.05) and with EDSS (p < 0.005) in the MS patients. The mixed water pools with a T2 above 110 ms were not related to age, but strongly increased with EDSS (p < 0.000005).Conclusion: Our results suggest that multicomponent T2 mapping of the WM can be a useful parameter for monitoring the progression of MS in patients.

Early Cartilage Changes After Anterior Cruciate Ligament Injury: Evaluation With Imaging and Serum Biomarkers—A Pilot Study

To determine if magnetic resonance imaging markers of cartilage matrix and morphology and circulating serum biomarkers of inflammation and matrix degradation differ over time in patients with anterior cruciate ligament (ACL) injury and bone marrow edema lesions (BMELs) when compared with matched control subjects. We performed a case-control study, in which 11 ACL-injured subjects scheduled to undergo reconstruction and 11 matched control subjects were scheduled for testing. Participants were selected for the ACL reconstruction (ACLR) group if they injured their ACL while participating in sports, were aged 14 to 30 years, had 1 or more BMELs, and were scheduled to undergo bone-patellar tendon-bone ACLR. Testing required patients to undergo magnetic resonance imaging for measurement of T2 relaxation times in standardized regions of interest over the medial and lateral tibial plateaus and femoral condyles and have blood drawn for measurement of cartilage oligomeric matrix protein (COMP) and C-reactive protein levels before ligament reconstruction and 1 year after surgery. ACL patients had prolonged T2 relaxation times, indicative of cartilage matrix degradation, in the superficial central lateral tibial plateau (P= .02) and deep medial tibial plateau when compared with control subjects (P= .0001). Prolonged T2 relaxation times were also noted over the lateral femoral condyle at baseline for ACL patients compared with control subjects (P= .001), but the differences resolved by 1 year (P= .98). Circulating serum COMP levels were greater in ACL patients (233.23 ± 88.26 ng/mL) compared with control subjects (169.05 ± 64.53 ng/mL, P= .05). T2 mapping showed prolonged relaxation times in the lateral compartment of the knee in ACLR patients with lateral BMELs. Furthermore, prolonged T2 relaxation times were apparent in the medial compartment of the knee in ACL-injured patients where bone marrow lesions were not present. Higher serum COMP levels were present in ACL-injured subjects when compared with control subjects. Level II, prospective case-control study.

MRI signal intensity differentiation of brainstem encephalitis induced by Enterovirus 71: a classification approach for acute and convalescence stages.

BackgroundThe objective of this study is to assess standardized histograms of signal intensities of T1 signal and T2 signal on sagittal view without enhancement during (1) acute stage, and (2) convalescence stage of pediatric patients with Enterovirus 71 related brainstem encephalitis (BE), and with respect to (3) healthy normal.MethodsOur subjects were hospitalized between March 2010 and October 2012, and underwent pre- and post-contrast MRI studies. The research question to be answered is whether the comparison of the MRI image intensity histograms and relevant statistical quantification can add new knowledge to the diagnosis of BE patients. So, both 25 cases in acute stage with prolonged T1 and T2 signal, without enhancement, and 13 cases in convalescence stage were introduced. In additional, a healthy group with 25 cases was recruited for comparison.ResultsMRI signal intensity histogram changes of the lesions were compared at the acute and convalescence stages of the disease. Our preliminary results suggest that standardized histograms of signal intensities and their statistical properties are able to provide diagnostic information for the clinical assessment of the disease. Different stages pertaining to the histogram plots comparison showed that overall T1 signal intensity values increase as we traverse from the acute stage to the convalescence stage. And then for the healthy subjects, the T2 signal intensity values changed their magnitudes in a reverse direction. However, exceptions of this can happen in four cases where the primary lesions occurred in the brainstem that developed encephalomalacia resulting in a lower signal in T1WI and higher signal in T2WI. Statistical analysis revealed there was significant difference of T1 signal intensity among the three groups; and also, the T2 signal intensity was lower than other two groups.ConclusionsStandardized histogram of T1 and T2 intensity provide valuable and useful information for disease diagnosis and evaluation, which can potentially help medical doctors to save the lives of children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12938-016-0136-7) contains supplementary material, which is available to authorized users.

MR imaging biomarkers for evaluating therapeutic effects shortly after near infrared photoimmunotherapy.

Near infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that combines the specificity of antibodies for targeting tumors with the toxicity induced by photon absorbers after irradiation with NIR light. The purpose of this study was to determine if MR imaging can detect changes in the MR properties of tumor within several hours of NIR-PIT. A431 cells were injected subcutaneously in the right and left dorsi of 12 mice. Six days later, the mice were injected with a photon absorber, IR700, conjugated to panitumumab, an antibody targeting epidermal growth factor receptor. One day later, only right sided tumor was exposed to NIR light (treated tumor). MRI was performed 1 day before and 1-2 hours after NIR-PIT using gadofosveset for six mice and gadopentetate dimeglumine for another six mice. T2 relaxation times, the apparent diffusion coefficient (ADC) for the following combinations of b-values: 0-1000, 200-1000 and 500-1000 s/mm2 and enhancement indices were compared before and after NIR-PIT using a two-sided paired t-test. For treated tumors, T2 relaxation time increased after NIR-PIT (p < 0.01) and all three ADC values decreased after NIR-PIT (p < 0.01). Moreover, the enhancement area under the curve (AUC) using gadofosveset increased after NIR-PIT (p = 0.02). In conclusion, prolongation of T2, reductions in ADC and increased enhancement using gadofosveset are seen within 2 hours of NIR-PIT treatment of tumors. Thus, MRI can be a useful imaging biomarker for detecting early therapeutic changes after NIR-PIT.

Assessment of cortical damage in early multiple sclerosis with quantitative T2 relaxometry.

T2 relaxation time is a quantitative MRI in vivo surrogate of cerebral tissue damage in multiple sclerosis (MS) patients. Cortical T2 prolongation is a known feature in later disease stages, but has not been demonstrated in the cortical normal appearing gray matter (NAGM) in early MS. This study centers on the quantitative evaluation of the tissue parameter T2 in cortical NAGM in a collective of early MS and clinically isolated syndrome (CIS) patients, hypothesizing that T2 prolongation is already present at early disease stages and variable over space, in line with global and focal inflammatory processes in MS. Additionally, magnetization transfer ratio (MTR) mapping was performed for further characterization of the expected cortical T2 alteration. Quantitative T2 and MTR maps were acquired from 12 patients with CIS and early MS, and 12 matched healthy controls. The lesion-free part of the cortical volume was identified, and the mean T2 and MTR values and their standard deviations within the cortical volume were determined. For evaluation of spatial specificity, cortical lobar subregions were tested separately for differences of mean T2 and T2 standard deviation. We detected significantly prolonged T2 in cortical NAGM in patients. T2 prolongation was found across the whole cerebral cortex and in all individual lobar subregions. Significantly higher standard deviations across the respective region of interest were found for the whole cerebral cortex and all subregions, suggesting the occurrence of spatially inhomogeneous cortical damage in all regions studied. A trend was observed for MTR reduction and increased MTR variability across the whole cortex in the MS group, suggesting demyelination. In conclusion, our results suggest that cortical damage in early MS is evidenced by spatially inhomogeneous T2 prolongation which goes beyond demyelination. Iron deposition, which is known to decrease T2, seems less prominent.

Subcutaneous sacrococcygeal ependymoma in a child

A nine-year-old girl presented with a sacral mass. The mass had been present since the first year of life and gradually increased in size. Physical examination revealed a palpable soft tissue mass at the midline over the sacrococcygeal region. Neurologic examination was unremarkable. The magnetic resonance imaging showed a well-defined, lobulated nonlipomatous mass with T1 and T2 prolongation (Fig. 1, Left, Middle). The overlying subcutaneous fat was intact and

Right Ventricular Involvement and Recovery After Acute Stress-Induced (Tako-tsubo) Cardiomyopathy

Acute stress-induced (Tako-tsubo) cardiomyopathy is an increasingly recognized but insufficiently characterized syndrome. Here, we investigate the pathophysiology of right ventricular (RV) involvement in Tako-tsubo and its recovery time course. We prospectively recruited 31 patients with Tako-tsubo with predominantly ST-elevation electrocardiogram and 18 controls of similar gender, age, and co-morbidity distribution. Patients underwent echocardiography and cardiac magnetic resonance (CMR) imaging on a 3T Philips scanner in the acute phase (day 0 to 3 after presentation) and at 4-months follow-up. Visually, echocardiography was able to identify only 52% of patients who showed RV wall motion abnormalities on CMR. Only CMR-derived RV ejection fraction (p = 0.01) and echocardiography-estimated pulmonary artery pressure (p = 0.01) identify RV functional involvement in the acute phase. Although RV ejection fraction normalizes in most patients by 4 months, acutely there is RV myocardial edema in both functioning and malfunctioning segments, as measured by prolonged native T1 mapping (p = 0.02 for both vs controls), and this persists at 4 months in the acutely malfunctioning segments (p = 0.002 vs controls). The extracellular volume fraction was significantly increased acutely in all RV segments and remained increased at follow-up compared with controls (p = 0.004 for all). In conclusion, in a Tako-tsubo population presenting predominantly with ST-elevation electrocardiogram, we demonstrate that although RV functional involvement is seen in only half of the patients, RV myocardial edema is present acutely throughout the RV myocardium in all patients and results in microscopic fibrosis at 4-month follow-up.

Eccentric exercise slows in vivo microvascular reactivity during brief contractions in human skeletal muscle

Unaccustomed exercise involving eccentric contractions results in muscle soreness and an overall decline in muscle function, however, little is known about the effects of eccentric exercise on microvascular reactivity in human skeletal muscle. Fourteen healthy men and women performed eccentric contractions of the dorsiflexor muscles in one leg, while the contralateral leg served as a control. At baseline, and 24 and 48 h after eccentric exercise, the following were acquired bilaterally in the tibialis anterior muscle: 1) transverse relaxation time (T2)-weighted magnetic resonance images to determine muscle cross-sectional area (mCSA) and T2; 2) blood oxygen level-dependent (BOLD) images during and following brief, maximal voluntary contractions (MVC) to monitor the hyperemic responses with participants positioned supine in a 3T magnet; 3) muscle strength; and 4) pain pressure threshold. Compared with the control leg, eccentric exercise resulted in soreness, decline in strength (∼20%), increased mCSA (∼7%), and prolonged T2 (∼7%) at 24 and 48 h (P < 0.05). The BOLD response to a brief MVC was altered 24 and 48 h after eccentric exercise, such that time-to-peak (∼35%, P < 0.05) and time-to-half-recovery (∼23%, P < 0.05) were prolonged. The altered contraction-induced hyperemic response suggests slowed microvascular reactivity and altered matching of O2 delivery to O2 utilization within muscle tissue showing signs of muscle damage. These changes in microvascular regulation after eccentric exercise may impede rapid adjustments in muscle blood flow at exercise onset and during activities involving brief bursts of muscle activation, which may impair O2 delivery and contribute to reduced muscle function after eccentric exercise.

Magnetic resonance imaging and spectroscopy in Fukuyama-type congenital muscular dystrophy

Fukuyama-type congenital muscular dystrophy (FCMD) is an autosomal recessive disorder characterized by congenital muscular dystrophy and associated with neuropathological anomalies such as polymicrogyria and pachygria. Cerebral abnormalities in FCMD have been well documented by neuropathological examinations and cranial imaging studies. However, the pathologic mechanism of white matter lesions remains controversial. In the present study, magnetic resonance imaging (MRI) of a 7-month-old boy with FCMD showed the previously reviewed characteristic morphological features such as thick cortices with shallow sulci corresponding to polymicrogyria involving the frontal lobe. MRI also showed markedly prolonged T1 and T2 signals in the white matter, while diffusion-weighted images showed no abnormalities. The results of magnetic resonance spectroscopy showed an increase in choline and N-acetylaspartate resonances but normal myo -inositol resonance. The simulation of these findings with those of merosin-negative congenital muscular dystrophy should suggest a further study with larger population using a combination of different imaging techniques.

Hypoglycemia associated with brain damage: a case report

We report a case of a 7-month-old infant with serial magnetic resonance imaging (MRI) confirmation of the neonatal hypoglycemia induced brain damage. Cranial MRI on day 17 revealed T1 and T2 prolongation of cortical and white matter in the parietal and occipital lobes bilaterally. A control cranial MRI on the seventh month showed shrunken and atrophied cortex and underlying white matter of the occipital and parietal lobes. Early and accurate diagnosis is critical in these patients, brain MRI is useful to assess the severity of brain damage associated with neonatal hypoglycemia. Besides detection of hypoglycemia, it is very important to find out underlying disorder to prevent sequelae.

Extra-ocular muscle MRI in genetically-defined mitochondrial disease.

ObjectivesConventional and quantitative MRI was performed in patients with chronic progressive external ophthalmoplegia (CPEO), a common manifestation of mitochondrial disease, to characterise MRI findings in the extra-ocular muscles (EOMs) and investigate whether quantitative MRI provides clinically relevant measures of disease.MethodsPatients with CPEO due to single mitochondrial DNA deletions were compared with controls. Range of eye movement (ROEM) measurements, peri-orbital 3 T MRI T1-weighted (T1w) and short-tau-inversion-recovery (STIR) images, and T2 relaxation time maps were obtained. Blinded observers graded muscle atrophy and T1w/STIR hyperintensity. Cross-sectional areas and EOM mean T2s were recorded and correlated with clinical parameters.ResultsNine patients and nine healthy controls were examined. Patients had reduced ROEM (patients 13.3°, controls 49.3°, p < 0.001), greater mean atrophy score and increased T1w hyperintensities. EOM mean cross-sectional area was 43 % of controls and mean T2s were prolonged (patients 75.6 ± 7.0 ms, controls 55.2 ± 4.1 ms, p < 0.001). ROEM correlated negatively with EOM T2 (rho = −0.89, p < 0.01), whilst cross-sectional area failed to correlate with any clinical measures.ConclusionsMRI demonstrates EOM atrophy, characteristic signal changes and prolonged T2 in CPEO. Correlation between elevated EOM T2 and ROEM impairment represents a potential measure of disease severity that warrants further evaluation.Key Points• Chronic progressive external ophthalmoplegia is a common clinical manifestation of mitochondrial disease.• Existing extra-ocular muscle MRI data in CPEO reports variable radiological findings.• MRI confirmed EOM atrophy and characteristic signal changes in CPEO.• EOM T2 was significantly elevated in CPEO and correlated negatively with ocular movements.• EOM T2 represents a potential quantitative measure of disease severity in CPEO.

MRI findings in Fukuyama-type congenital muscular dystrophy of Chinese

Objective To investigate the MRI features of Fukuyama-type congenital muscular dystrophy(FCMD) in Chinese. Methods The MRI and clinical data of 3 patients with FCMD which had been diagnosed by gene analysis were retrospectively analyzed.Two females and one male were included in this study, and they underwent MR examination at 0.5,2.3,5.0 years old respectively. The main clinical manifestations were muscular hypotonia and severe developmental delay. Abnormalities on MR images were analyzed and recorded by two experienced radiologists. Results Unlayerdpoly microgyria involved in frontal lobes, numerous intraparenchymal cysts at the peripheral hemispheres and prolonged T1 and T2 signal in the white matter were found in all the 3 cases. Disorganized cerebellar folia, lissencephaly of cerebral cortices, flattened pons were detected in 2 cases. Cystic region of white matter incerebral cortices and enlarged fourth ventricle could be seen in one case. Conclusion There are typical MR imaging featuresof FCMD, and preliminary diagnosis can be made by the combination with clinical symptoms and biochemical analysis. Key words: Muscular dystrophies; Brain; Magnetic resonance imaging