Area Of Abnormal Signal Intensity Research Articles

Presence of Auditory Pathway Abnormalities in Children With Neurofibromatosis Type 1 With Brainstem Focal Areas of Abnormal Signal Intensity: Diffusion Tensor Imaging Features

Background: To investigate whether there is a difference in mean diffusivity (MD) and fractional anisotropy (FA) values in the auditory pathways of neurofibromatosis type 1 patients with and without focal areas of abnormal signal intensity (FASI) compared to healthy controls by using diffusion tensor imaging (DTI). Methods: Patients were classified as group 1 with focal areas of abnormal signal intensity in the brainstem, group 2 without focal areas of abnormal signal intensity, and healthy control group 3 according to the MRI findings. Mean diffusivity and fractional anisotropy values of lateral lemniscus, inferior colliculus, corpus geniculatum mediale, Heschl gyrus, and brainstem were compared between groups. The correlation between mean diffusivity and fractional anisotropy values of auditory pathways and age was investigated. Results: There was a significant difference between group 1 and group 2 in terms of mean diffusivity and fractional anisotropy values at lateral lemniscus, inferior colliculus, corpus geniculatum mediale, and Heschl gyrus. Increased mean diffusivity and decreased fractional anisotropy values at brainstem were found in group 1. There was a significant difference between group 1 and group 3 in terms of mean diffusivity values at all auditory pathways. Fractional anisotropy values obtained from lateral lemniscus, inferior colliculus, and Heschl gyrus decreased in group 1 compared with group 3. There was a negative correlation between mean diffusivity values and positive correlation between fractional anisotropy values at lateral lemniscus, inferior colliculus, Heschl gyrus, and age. Conclusions: Our diffusion tensor imaging findings show that the neuronal integrity of the auditory pathways is affected in neurofibromatosis type 1 patients with brainstem focal areas of abnormal signal intensity. We think that the disappearance of brainstem focal areas of abnormal signal intensity associated with myelin repair and the regression of diffusion tensor imaging changes in the auditory pathways occur simultaneously with advancing age in patients with neurofibromatosis type 1.

Hemispheric encephalitis secondary to HAV

A 2-year male child, presented to National Institute of Child Health (NICH), with acute onset high grade fever and focal left sided seizures for 1 day, followed by left hemiparesis and encephalopathy. Developmental and family history was unremarkable. On physical examination, patient’s body temperature rose up to 38.7 °C. Though he had pallor along with hepatomegaly, there were no signs of jaundice or ascites. Central nervous system examination showed encephalopathy as well as positive neck stiffness. Motor system examination revealed generalized decrease in bulk of upper and lower limbs, but rest of the findings were localized to left side of the body, showing hypertonia, decreased power, brisk muscle stretch reflex, and positive ankle clonus and left Babinski sign.
 Blood investigations showed anemia (hemoglobin 9.1g/dl), leukocytosis (white blood cells 22.1 cells/μL) and raised aspartate aminotransferase (AST) levels (826 IU/L). Total bilirubin and direct bilirubin levels were normal (0.3 mg/dL and 0.1 mg/dL, respectively). Serum ammonia (64 μg/dL) and lactic acid (1.6 μg/dL) levels were also within normal ranges. The cerebrospinal fluid (CSF) was also clear, with 0 leukocytes/μL, protein levels of 25 mg/dL, and normal glucose levels (82 mg/dL), no organism was seen on gram stain. Hepatitis A Ig M antibody came out to be reactive.
 Brain computed tomography showed large hypo density along with effacement of sylvian fissure, sulci, gyri on right side involving frontal, parietal, and temporal and occipital lobe on ipsilateral side. On post contrast, there was remarkable meningeal enhancement on right side. MRI brain revealed cortical and subcortical large area of abnormal signal intensity seen in fronto-parietal and occipital cortex on the right side along with laminar necrosis.
 Seizures were controlled by given intravenous injection phenytoin and leviteracetam in bolus and then maintenance doses. Intravenous acyclovir was started
 due to clinical suspicion of herpes encephalitis but was stopped after observing clinical improvement and identification of Ig M antibody of HAV. Patient conscious level improved after 2 weeks. AST levels also decreased to 20 IU/L and he was discharged with advice to follow up after 14 days

Platelet-rich plasma combined with allograft to treat osteochondritis dissecans of the knee: a case report

BackgroundOsteochondritis dissecans of the knee is a prevalent pathology in young, active people that is brought about by either traumatic, developmental, or iatrogenic etiologies.Case presentationA 40-year-old Caucasian man reporting pain, swelling, and functional reduction was evaluated and diagnosed with internal condyle osteochondritis dissecans of the knee. Harnessing the trophic, chondroprotective, anti-inflammatory, and immunomodulatory properties of platelet-rich plasma, we carried out a knee open-sky surgical technique in which we combined autologous therapy with osteochondral allograft to treat the focal, large, and deep traumatic-iatrogenic osteochondritis dissecans of the knee. The axial computed tomographic scan taken 1 year after surgery revealed an area of abnormal signal intensity that was reduced on a computed tomographic scan 2 years later. The computed tomographic scan obtained 2 years later and the magnetic resonance imaging scan 3 years later also showed a clear reattachment and incorporation of the graft. Seven years after the surgery, the patient resumed his daily routine without any recurrent symptoms.ConclusionPlatelet-rich plasma application in osteochondral allograft implantation open surgery could enhance the healing process of medial condyle osteochondritis dissecans of the knee.

Diffusion weighted MR imaging in the diagnosis of acute pyelonephritis and its complications: A prospective observational study

Introduction: In diagnosing complicated pyelonephritis, imaging is essential for which traditionally computed tomography (CT) has been in use but in renal failure patients contrast enhanced CT can't be performed due to elevated serum creatine levels. This can be overcome with the help of Diffusion weighted (DW) magnetic resonance imaging (MRI). Purpose: To assess the morphological changes and signal abnormalities, in kidneys in patients with acute pyelonephritis (APN) on conventional MRI and DWI and to measure the ADC values in areas of abnormal signal intensity in DWI so as to differentiate between abscess and nephritis. Materials and Methods: In our study, 32 patients with clinical and laboratory diagnosis of pyelonephritis underwent conventional and Diffusion weighted MRI. Diffusion images were obtained by using a non-breath-hold, single-shot echo-planar sequence with b values of 50/400/800 s/mm2. Circular regions of interest were drawn in the areas of normal renal parenchyma, nephritis and abscesses. The ADC values of three tissue types were compared by using the paired t-test and ANOVA.P value Results: In our study, areas of normal renal parenchyma showed ADC values of (1.83 ± 0.06) × 10-3 mm2/s while areas of nephritis had ADC values of (1.20 ± 0.08) × 10-3 mm2/s which was significantly lower (P Conclusion: Diffusion weighted MR imaging is useful to diagnose abscess formation in patients with pyelonephritis without using IV contrast medium.

Radiation Necrosis and White Matter Lesions in Pediatric Patients With Brain Tumors Treated With Pencil Beam Scanning Proton Therapy

To assess the rate of radiation necrosis (RN) and white matter lesions (WMLs) in pediatric patients with primary brain tumors treated with pencil beam scanning (PBS) proton therapy (PT) with or without concomitant chemotherapy at the PSI. Between 1999 and 2015, 171 pediatric patients (age <18years) were treated with PT. Median age at diagnosis was 3.3years (range, 0.3-17.0years), and the median delivered dose was 54Gy (relative biological effectiveness) (range, 40.0-74.1Gy). Radiation necrosis and WMLs were defined as a new area of abnormal signal intensity on T2-weighted images or increased signal intensity on T2-weighted images, and contrast enhancement on T1 occurring in the brain parenchyma included in the radiation treatment field, which did not demonstrate any abnormality before PT. Radiation necrosis and WMLs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The median follow-up period for the surviving patients was 49.8months (range, 5.9-194.7months). Twenty-nine patients (17%) developed RN at a median time of 5months (range, 1-26months), most of them (n = 17; 59%) being asymptomatic (grade 1). Grade 2, 4, and 5 toxicities occurred in 8, 2, and 2 patients, respectively. Eighteen patients (11%) developed WMLs at a median time of 14.5months (range, 2-62months), most of them (n = 13; 72%) being asymptomatic (grade 1). White matter lesion grade 2 and 3 toxicities occurred in 4 and 1 patient(s), respectively. The 5-year RN-free andWML-free survival was 83% and 87%, respectively. In univariate analysis, neoadjuvant (P = .025) or any (P = .03) chemotherapy, hydrocephalus before PT (P = .035), and ependymoma (P = .026) histology were significant predictors of RN. Children treated with PT demonstrated a low prevalence of symptomatic RN (7%) or WML (3%) compared with similar cohorts treated with either proton or photon radiation therapy. Chemotherapy, ependymomal tumors and hydrocephalus as an initial symptom were significant risk factors for RN.

Differentiation of acute osteoporotic from malignant vertebral compression fractures with conventional MRI and diffusion MR imaging

AimTo evaluate the role of using a single shot spin echoplanar DW sequence (SSSEP-DWI) compared to conventional MRI and contrast enhanced T1WI in differentiation between vertebral osteoporotic fractures and malignant compression fractures. The sensitivity and specificity of (SSSEP-DWI) will also be calculated. Patients and methodsSixty-eight acute vertebral compression fractures in 41 patients were imaged using conventional MRI, fat suppressed contrast enhanced T1WI and DW sequence on a 1.5T MR machine. Quantitative assessment of the abnormal signal intensity was done by measuring apparent diffusion coefficients (ADCs). Also, the areas of abnormal signal intensity were compared to adjacent normal marrow. ResultsWe had 38 benign fractures, and 30 malignant fractures. Post contrast enhancement showed sensitivity of 92% and specificity of 70% for malignant compression fractures. The hyperintense signal on DWI has 89% PPV for malignancy, while the sensitivity and specificity were 86% and 91% respectively. The mean ADC for malignant fractures was significantly lower than those of osteoporotic fractures (p=0.0002). ConclusionsSSSEP-DWI is a reliable adjunct parameter that supports conventional MRI in differentiating benign and malignant vertebral fractures.

Neuromyelitis Optica: Atypical Clinical and Neuroradiological Presentation

The extreme variability of clinical and MRI findings in the suspicion of Devic's disease always requires the detection of specific antibodies (AQP4). MRI scans were performed with a high-field MRI scanner (1.5T General Electric Signa Horizon): the MRI protocol of the brain employed axial DP, T2, T1, FLAIR and DWI weighted images (wi) and coronal T2-wi. After intravenous administration of contrast medium axial and sagittal T1-weighted images of the brain were repeated. The spine protocol employed after contrast medium included sagittal T2-wi, T2-wi with fat suppression and T1-wi. In May 2004, a 64-year-old healthy Caucasian woman began to suffer loss of motor and thermal sensitivity in the left lower limb. MRI showed non-specific areas of abnormal signal intensity on the deep left frontal and right frontoparietal white matter with no pathological enhancement after contrast medium and a small intramedullary area of altered signal at metameric level C2-C4 with a diagnosis of post-viral transverse myelitis. The patient had two similar episodes years later so the neurologist decided to search for circulating IgG AQP4 with the definitive diagnosis of neuromyelitis optica. In this case, compared to a clinical presentation of atypical deficit neurological involvement, the neuroradiological results of a progressive diffuse involvement of the white matter were atypical.

Abstract MP27: Cardiovascular Biomarkers and MRI-defined Small Vessel Disease of the Brain in the Atherosclerosis Risk in Communities (ARIC) Study

Background: Cerebrovascular and cardiovascular disease share common risk factors. Thus, biomarkers associated with subclinical cardiac injury may also be associated with silent cerebral injury. We hypothesized that levels of N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin T measured with a highly sensitive assay (hs-cTnT) are associated with silent brain infarcts (BI) and white matter lesions (WML) on magnetic resonance imaging (MRI) in the Atherosclerosis Risk In Communities (ARIC) study. Methods: Brain MRI was performed at ARIC visit 3 (1993-1995) on 1920 participants. NT-proBNP and hs-cTnT were measured in all individuals at ARIC visit 4 (1996-1998). A subset (N=1112) of those individuals who had the initial MRI at Visit 3, had a follow up MRI in 2004-2006. We analyzed the association of NT-proBNP and hs-cTnT with the presence of MRI defined BI and WML on the initial MRI and on the follow-up MRI in participants without coronary heart disease and stroke. BI was defined as an area of abnormal signal intensity in a vascular distribution, ≥ 3 millimeters in size, and without mass effect. WML were estimated as the total volume of periventricular and subcortical white matter-signal abnormality. Results: In the adjusted model, individuals in the highest NT-proBNP quartile had significantly more BI and WML on the baseline MRI and more incident BI and WML progression on the follow up MRI when compared to the lowest quartile (Table). In the same model, individuals in the highest hs-cTnT category had significantly more BI and WML on the initial MRI and more WML progression on the follow up MRI when compared to the lowest category. Incident BIs were significantly more common in the 0.009 to ≤0.013 μg/L troponin category but not in the highest one, when compared to the lowest category (Table). Conclusion: NT-proBNP and hs-cTnT are independently associated with silent MRI-defined BI and WML suggesting that biomarkers for subclinical cardiac injury may also be useful to identify individuals with subclinical cerebral injury.

Cerebellar Gliomatosis in a Toddler

Gliomatosis confined to the cerebellum is most unusual. We report such a case in a 20-month-old male who presented with unsteadiness. Magnetic resonance imaging revealed a diffuse area of abnormal signal intensity within both cerebellar hemispheres, which did not enhance after contrast administration. The patient underwent a biopsy, which revealed a diffuse glioma infiltrating the cerebellum. Overall, the tumor cells had oligodendroglioma-like features and exhibited only focal vimentin immunoreactivity. They were negative for glial fibrillary acidic protein, synaptophysin, βIII-tubulin, and neurofilament protein. Immunofluorescence, performed on primary biopsy explants maintained in cell culture without exposure to growth factors or differentiation-promoting agents, revealed widespread nestin immunoreactivity and immunolabeling of occasional cells with antibodies to platelet-derived growth factor-α and O1/O4, markers of oligodendrocyte precursor-cells and immature oligodendrocytes, respectively. Fluorescent in situ hybridization performed on explants, touch preparations, and paraffin sections failed to reveal loss of heterozygosity for either 1p36 or 19q13. The patient was treated with temozolomide and remains stable, albeit with residual quiescent tumor, more than 3 years after surgery. This report calls attention to an unusual presentation of gliomatosis confined to the cerebellum of a toddler and addresses salient aspects of clinical and radiological differential diagnosis, as well as therapeutic challenges encountered.

Can Necrotizing Infectious Fasciitis Be Differentiated from Nonnecrotizing Infectious Fasciitis with MR Imaging?

To retrospectively evaluate whether magnetic resonance (MR) imaging findings can be used to differentiate necrotizing infectious fasciitis (NIF) from nonnecrotizing infectious fasciitis (non-NIF). Institutional review board approval was obtained, but patient consent was not required for this retrospective review of records and images because patient anonymity was preserved. Thirty patients (seven with NIF, 23 with non-NIF) were included in the study. The following imaging findings were analyzed on fat-suppressed T2-weighted MR images: (a) signal intensity in the deep fascia (low, high, or mixed high and low), (b) thickness of abnormal signal intensity in the deep fascia (≥3 mm or <3 mm), (c) pattern of abnormal signal intensity in muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity), (d) degree of deep fascia involvement (partial or extensive), and (e) degree of compartment involvement (fewer than three compartments or three or more compartments). On contrast material-enhanced fat-suppressed T1-weighted images, the contrast enhancement patterns of the abnormal deep fascia (no enhancement, enhancement, or enhancement with nonenhancing portion) and the muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity) were evaluated. The presence of abscesses in the subcutaneous fat layer was evaluated with all sequences. The patients with NIF had a significantly greater frequency of (a) thick (≥3 mm) abnormal signal intensity on fat-suppressed T2-weighted images, (b) low signal intensity in the deep fascia on fat-suppressed T2-weighted images, (c) a focal or diffuse nonenhancing portion in the area of abnormal signal intensity in the deep fascia, (d) extensive involvement of the deep fascia, and (e) involvement of three or more compartments in one extremity (P < .05). MR imaging is potentially helpful for differentiating NIF from non-NIF. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101164/-/DC1.

Transient supranuclear paresis of the abduction in viral encephalitis of the brainstem

The supranuclear paresis of the abducens system, also known as posterior internuclear ophthalmoplegia of abduction, is a very rare disorder clinically characterized by unilateral or bilateral abduction paresis sometimes associated with nystagmus of the contralateral adducting eye, slowing of abduction saccades, and intact horizontal vestibulo-ocular reflex. Here, we report a 35-year-old woman who presented transient left side abduction deficit in conjunction, as the only symptom of self-limited viral encephalitis of the brainstem. Brain MRI including DWI and ADC maps showed an area of abnormal signal intensity in the mid-right ponto-mesencephalic junction. PCR analysis of cerebrospinal fluid showed an enterovirus infection. Spontaneous clinical recovery rapidly occurred 2 days after onset. The brainstem lesion was undetectable at 5-week brain MRI follow-up.

Neuroimaging in myotonic dystrophy type 1

A 56-year-old woman with a 10-year history of myotonic dystrophy type 1 (MD) presented with progressive lower extremity weakness. MRI showed multiple discrete and confluent areas of abnormal signal intensity throughout the subcortical white matter with predominant involvement of …

Magnetoencephalographic Findings in Two Cases of Juvenile Myoclonus Epilepsy

The aim of this study is to investigate the electromagnetic sources of epileptic activity in two patients with juvenile myoclonus epilepsy (JME). The first patient was a 22-year old female with JME diagnosis by the age of 17 years old. Her initial EEG recording showed characteristic paroxysmal generalized activity with polyspike-wave complexes. She was on remission for 9 months. The second patient was a 29-year old male with JME diagnosis by the age 18 of years old. He showed an EEG recording with generalized spike-wave complexes of 3.5-4 Hz and presented a great improvement after therapeutic treatment. The MRI examinations for both patients did not disclose any focal lesions or areas of abnormal signal intensity or enhancement by contrast media. Magnetoencephalography (MEG) was recorded with a 122-channel whole-head system, 5 years after the disease onset for the first patient and 11 years for the second patient. For the first patient dipolar sources of MEG paroxysmal activity were localised at the vermis with extension up to the occipital region, whereas, for the second patient dipolar sources of MEG paroxysmal activity were localised at the cerebellar area (vermis and hemisphere). Implication of the cerebellum in JME, as suggested by MEG data in this study, is in accordance with previous reports employing functional MRI or cerebral blood flow evaluation in JME.

Cerebral vasculitis and unilateral sixth-nerve palsy in acute post-streptococcal glomerulonephritis

Cerebral vasculitis associated with acute post-streptococcal glomerulonephritis (APSGN) is rare. A 13-year-old girl presented with severe headache, vomiting, oedema and macroscopic haematuria. There was a history of upper respiratory infection 2 weeks previously. A diagnosis of APSGN was made. On admission, she was normotensive and biochemically well balanced. She experienced a tonic-clonic seizure 2 hours later. An MRI brain scan demonstrated multiple areas of abnormal signal intensity in the cerebral and cerebellar white matter, and subarachnoid haemorrhage consistent with vasculitis was diagnosed. A sixth-nerve palsy developed on the 6th day of admission. An elevated anti-streptolysin titre and low serum C3 complement level together with typical features on renal biopsy supported the diagnosis of APSGN. All clinical and laboratory abnormalities improved with corticosteroid therapy, pulse methyl-prednisolone. APSGN can present with central nervous system abnormalities without hypertension, uraemia and electrolyte disturbance.

Targeting optimal biopsy location in basal ganglia germinoma using 11C-methionine positron emission tomography

Background Approximately 5% to 10% of intracranial germinomas arise from the basal ganglia or thalamus. Diagnosis is usually made by stereotactic biopsy, and precise location of the biopsy target is crucial because germinoma in these sites is potentially curable. We herein describe a case with germinoma in the basal ganglia that showed nonspecific clinical and radiological findings. The usefulness of MET-PET in locating an optimal biopsy target and monitoring treatment efficacy in this case is presented. Case Description A 9-year-old boy presented with a 4-month history of dystonia in his left upper extremity. Magnetic resonance imaging of the brain showed abnormal signal intensity in the right basal ganglia, internal capsule, and corona radiata without mass formation and enhancement effect. He had been treated as having multiple sclerosis without improvements on clinical and radiological findings. The MET-PET study showed increased tracer uptake in the areas of abnormal signal intensity on the MR images, and the MRI-PET co-registered images exhibited the highest tracer uptake in the anterior limb of the internal capsule. A stereotactic biopsy targeting the highest tracer uptake lesion was performed with histologic verification of germinoma. He was intensively treated with combined chemotherapy and radiotherapy according to the MR images and MET-PET findings. After the treatment, the area of abnormal signal intensity significantly reduced in size on the follow-up MRI and lesional tracer uptake was also decreased on MET-PET images. Conclusion The MET-PET study is very useful for locating a precise biopsy target and provides useful information in monitoring treatment efficacy in the basal ganglia germinoma that showed nonspecific radiological findings.

22q13 microduplication in two patients with common clinical manifestations: A recognizable syndrome?

We report here on two unrelated patients (Patients 1 and 2) with a cryptic microduplication involving a 22q13 segment. Both patients manifested infantile hypotonia, developmental delay, and growth deficiency. In addition, an abnormal signal intensity area was detected in the frontal white matter of Patient 2 by brain MRI. Whole-genome microarray comparative genomic hybridization for Patient 1 and fluorescence in situ hybridization analysis with 22q-subtelomeric probes performed in both patients showed a submicroscopic 22q13 duplication that involved the SHANK3 gene. The duplication in Patient 1 was de novo type, while that in Patient 2 was derived from a familial 17;22 translocation. The presence of common clinical manifestations in the two patients with the common duplicated region led to a conclusion that 22q terminal duplication is a recognizable clinical entity, that is, the 22q13 microduplication syndrome.

Magnetic resonance imaging and positron emission tomography findings in status epilepticus following severe hypoglycemia

We recently experienced a case with asymmetrical cortical abnormality on MRI with focal status epilepticus following severe hypoglycemia. The cerebral blood flow and metabolisms for oxygen and glucose were determined using positron emission tomography (PET) during focal status epilepticus following severe hypoglycemia and at the follow-up period. Prolonged seizure activity produced profound glucose hypermetabolism and mild hyperemia in the region of the presumed cortical focus of epilepsy and in structures anatomically remote from the focus, corresponding to the areas of abnormal signal intensity on the MRI. The patient remained comatose and exhibited a diffuse hypoperfusion/hypometabolism and symmetrical brain atrophy on the follow-up PET and MRI, respectively. Cytotoxic brain edema due to profound glucose metabolism without compensatory increase of the blood flow during status epilepticus may account for the brain abnormality observed on the early MRI. Simultaneous examination of the cerebral blood flow and metabolism using PET can provide useful information about the pathology in patients with status epilepticus.

Differentiation of Recently Infarcted Myocardium from Chronic Myocardial Scar: The Value of Contrast-Enhanced SSFP-Based Cine MR Imaging

The purpose of this study is to demonstrate whether the signal intensity (SI) of myocardial infarction (MI) on contrast enhanced (CE)-cine MRI is useful for differentiating recently infarcted myocardium from chronic scar. This study included 24 patients with acute MI (36-84 years, mean age: 57) and 19 patients with chronic MI (44-80 years, mean age: 64). The diagnosis of acute MI was based on the presence of typical symptoms, i.e. elevation of the cardiac enzymes and the absence of any remote infarction history. The diagnosis of chronic MI was based on a history of MI or coronary artery disease of more than one month duration and on the absence of any recent MI within the previous six months. Retrospectively, the ECG-gated breath-hold cine imaging was performed in the short axis plane using a segmented, balanced, turbo-field, echo-pulse sequence two minutes after the administration of Gd-DTPA at a dose of 0.2 mmol/kg body weight. Delayed contrast-enhanced MRI (DCE MRI) in the same plane was performed 10 to 15 minutes after contrast administration, and this was served as the gold standard of reference. The SI of the infarcted myocardium on the CE-cine MRI was compared with that of the normal myocardium on the same image. The area of abnormal SI on the CE-cine MRI was compared with the area of hyperenhancement on the DCE MRI. The area of high SI on the CE-cine MRI was detected in 23 of 24 patients with acute MI (10 with homogenous high SI, 13 high SI with subendocardial low SI, and one with iso SI). The area of high SI on the CE-cine MRI was larger than that seen on the DCE MRI (p < 0.05). In contrast, the areas of chronic MI were seen as iso-SI with thin subendocardial low SI on the CE-cine MR in all the chronic MI patients. The presence of high SI on both the CE-cine MRI and the DCE MRI is more sensitive (95.8%) for determining the age of a MI than the presence of myocardial thinning (66.7%). This study showed the different SI patterns between recently infarcted myocardium and chronic scar on the CE-cine MRI. CE-cine MRI is thought to be quite useful for determining the age of myocardial infarction, in addition to its utility for assessing myocardial contractility.

Two Cases of Subacute Combined Degeneration: Magnetic Resonance Findings

We report two cases of subacute combined degeneration. Both patients had undergone total gastrectomy. The chief complaints were numbness in both upper extremities in case 1 and numbness in both the upper and lower extremities and gait disturbance in case 2. The pain, temperature, and vibration senses of both patients were decreased. Laboratory examinations showed macrocytic anemia and a decreased serum vitamin B12 level in both cases. In both cases T2-weighted magnetic resonance images showed an area of hyperintensity in the dorsal columns of the cervical spinal cord. The patients were treated with vitamin B12. The abnormal signals had disappeared on follow-up magnetic resonance examination 1 year later in case 1 and 3 months later in case 2. These patients showed neurological improvement, but the numbness in the upper extremities persisted even after the area of abnormal signal intensity had disappeared in case 1.

MAGNETIC RESONANCE IMAGING FINDINGS IN THE EQUINE DEEP DIGITAL FLEXOR TENDON AND DISTAL SESAMOID BONE IN ADVANCED NAVICULAR DISEASE—AN EX VIVO STUDY

We describe the abnormal magnetic resonance (MR) imaging findings in the deep digital flexor tendon (DDFT) and distal sesamoid bone in horses with radiographic changes compatible with navicular syndrome. Thirteen postmortem specimens were examined using a 1.5-T magnetic field, with spin echo (SE) T1-weighted, turbo SE (TSE) proton density-weighted (with and without fat saturation), and fat saturation TSE T2-weighted sequences. The limbs were then dissected to compare the MR findings with the gross assessment and histologic examination of the DDFT and distal sesamoid bones. Tendonous abnormalities were detected by MR imaging in 12 DDFTs and confirmed at necropsy. Most tendon lesions were located at the level of the distal sesamoid bone and the proximal recess of the podotrochlear bursa. Tendon lesions were classified based on their MR imaging features as core lesions, dorsal lesions, dorsal abrasions, and parasagittal splits. Areas of increased MR signal in the DDFTs were characterized by tendon fiber disturbance and lack of continuity of the collagen fibers, foci of edema, hemorrhages, and formation of lakes containing eosinophilic plasma-like material or amphophilic material of low density. Bone marrow signal alterations in the distal sesamoid bone were seen in all digits. Two main phenomena were responsible for the abnormal signal, respectively, in T1-weighted (decreased signal) and in T2-weighted fat-suppressed images (increased signal): a decrease in the fat marrow content in the trabecular spaces and an increase in the fluid content. Histologic examination revealed foci of bone marrow edema, hemorrhage, necrosis, and fibrosis. Cyst formation and trabecular abnormalities (disorganization, thinning, remodelling) were also observed in areas of abnormal signal intensity. Increased bone density because of trabecular thickening induced a decrease in signal in all sequences.