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Purpose@#This study aimed to evaluate angiographic and contrast enhancement (CE) patterns on three-dimensional (3D) black blood (BB) contrast-enhanced MRI in patients with acute medulla infarction. @*Materials and Methods@#From January 2020 to August 2021, we retrospectively analyzed stroke 3D BB contrast-enhanced magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) findings of patients visiting the emergency room for symptom evaluation of acute medulla infarction. In total, 28 patients with acute medulla infarction were enrolled in this study. Four types of 3D BB contrast-enhanced MRI and MRA were classified as follows: 1=unilateral contrast-enhanced vertebral artery (VA)+no visualization of VA on MRA; 2=unilateral enhanced VA+hypoplastic VA; 3=no enhanced VA+unilateral complete occlusion of VA; 4=no enhanced VA+normal VA (including hypoplasia) on MRA. @*Results@#Of the 28 patients with acute medulla infarction, 7 (25.0%) showed delayed positive findings after 24 hours on diffusion-weighted imaging (DWI). Of these patients, 19 (67.9%) showed CE of the unilateral VA on 3D BB contrast-enhanced MRI (type 1 and 2). Of the 19 patients with CE of VA on 3D BB contrast-enhanced MRI, 18 showed no visualization of enhanced VA on MRA (type 1), and 1 showed hypoplastic VA. Of the 7 patients with delayed positive findings on DWI, 5 showed CE of the unilateral VA and no visualization of the enhanced VA on MRA (type 1). Symptom onset to door time or initial MR check time was significantly shorter in the groups with delayed positive findings on DWI (P<0.05). @*Conclusion@#Unilateral CE on 3D BB contrast-enhanced MRI and no visualization of the VA on MRA are related to the recent occlusion of the distal VA. These findings suggest that the recent occlusion of the distal VA is related to acute medulla infarction, including delayed visualization on DWI.
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Purpose@#To investigate the diagnostic criteria of T1-weighted imaging (T1W) and time-of-flight (TOF) imaging for detecting intraplaque hemorrhage (IPH) of a vertebrobasilar artery (VBA) compared with simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) imaging. @*Materials and Methods@#Eighty-seven patients with VBA atherosclerosis who underwent high resolution MR imaging for evaluation of VBA plaque were reviewed. The presence and location of VBA plaque and IPH on SNAP were determined. The signal intensity (SI) of the VBA plaque on T1W and TOF imaging was manually measured and the SI ratio against adjacent muscles was calculated. The receiveroperating characteristic (ROC) curve was used to compare the diagnostic accuracy for detecting VBA IPH. @*Results@#Of 87 patients, 67 had IPH and 20 had no IPH on SNAP. The SI ratio between VBA IPH and temporalis muscle on T1W was significantly higher than that in the noIPH group (235.9 ± 16.8 vs. 120.0 ± 5.1, P < 0.001). The SI ratio between IPH and temporalis muscle on TOF was also significantly higher than that in the no-IPH group (236.8 ± 13.3 vs. 112.8 ± 7.4, P < 0.001). Diagnostic efficacies of SI ratios on TOF and TIW were excellent (AUC: 0.976 on TOF and 0.964 on T1W; cutoff value: 136.7% for TOF imaging and 135.1% for T1W imaging). @*Conclusion@#Compared with SNAP, cutoff levels of the SI ratio between VBA plaque and temporalis muscle on T1W and TOF imaging for detecting IPH were approximately 1.35 times.
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PURPOSE: To determine the value of the appearance of the high signal intensity halo sign for detecting carotid intraplaque hemorrhage (IPH) on maximum intensity projection (MIP) of time-of-flight (TOF) MR angiography (MRA), based on high signal intensity on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) sequencing. MATERIALS AND METHODS: A total of 78 carotid arteries in 65 patients with magnetization-prepared rapid acquisition gradient-echo (MPRAGE) positive on carotid plaque MR imaging were included in this study. High-resolution MR imaging was performed on a 3.0-T scanner prior to carotid endarterectomy or carotid artery stenting. Fast spin-echo T1- and T2-weighted axial imaging, TOF, and MPRAGE sequences were obtained. Carotid plaques with high signal intensity on MPRAGE > 200% that of adjacent muscle on at least two consecutive slices were defined as showing IPH. Halo sign of high signal intensity around the carotid artery was found on MIP from TOF MRA. Continuous and categorical variables were compared among groups using the Mann-Whitney test and Fisher's exact tests. RESULTS: Of these 78 carotid arteries, 53 appeared as a halo sign on the TOF MRA. The total IPH volume of patients with a positive halo sign was significantly higher than that of patients without a halo sign (75.0 ± 86.8 vs. 16.3 ± 18.2, P = 0.001). The maximum IPH axial wall area in patients with a positive halo sign was significantly higher than that of patients without a halo sign (11.3 ± 9.9 vs. 3.7 ± 3.6, P = 0.000). CONCLUSION: High signal intensity halo of IPH on MIP of TOF MRA is associated with total volume and maximal axial wall area of IPH.
Subject(s)
Humans , Angiography , Atherosclerosis , Carotid Arteries , Endarterectomy, Carotid , Hemorrhage , Magnetic Resonance Imaging , StentsABSTRACT
Superior oblique myokymia (SOM) is a rare disorder characterized by unilateral paroxysmal oscillopsia or diplopia. Recent studies revealed that SOM can be associated with neuro-vascular cross compression (NVCC) of the trunk of the trochlear nerve. Although it frequently occurs without any underlying systemic disease or concurrent neurologic sign, we need to consider this NVCC especially in cases with persistent disturbing symptoms. Hereby, we present two cases of SOM whose neuroimaging studies suggest NVCCs and, discuss recent update of the pathomechanism of SOM.
Subject(s)
Diplopia , Nerve Compression Syndromes , Neuroimaging , Neurologic Manifestations , Trochlear Nerve , Trochlear Nerve DiseasesABSTRACT
OBJECTIVE: To compare apparent diffusion coefficient (ADC) of the upper abdominal organs acquired with multiple b-value combinations and to investigate usefulness of normalization. MATERIALS AND METHODS: We retrospectively analyzed data, including 3T diffusion-weighted images, of 100 patients (56 men, 44 women; mean age, 63.9) that underwent liver magnetic resonance imaging. An ADC map was derived with the following six b-value combinations: b1 = 0, 50, 400, 800; b2 = 0, 800; b3 = 0, 50, 800; b4 = 0, 400, 800; b5 = 50, 800; and b6 = 50, 400, 800 s/mm2. ADC values of the right liver lobe, left liver lobe, spleen, pancreas, right kidney, and left kidney were measured. ADC values of the spleen were used for normalization. Intraclass correlation coefficients (ICCs), comparison of dependent ICCs, and repeated-measures analysis of variance were used for statistical analysis. RESULTS: Intraclass correlation coefficients of the original ADC revealed moderate to substantial agreement (0.5145–0.6509), while normalized ADCs revealed almost perfect agreement (0.8014–0.8569). ICC of normalized ADC for all anatomical regions revealed significantly less variability than that of the original ADC (p < 0.05). Coefficient of variance for normalized ADC was significantly lower than that for the original ADC (3.0.3.8% vs. 4.8.8.8%, p < 0.05). CONCLUSION: Normalization of the ADC values of the upper abdominal organs using the spleen as the reference organ significantly decreased variability in ADC measurement acquired with multiple b-value combinations.
Subject(s)
Female , Humans , Male , Diffusion , Kidney , Liver , Magnetic Resonance Imaging , Pancreas , Retrospective Studies , SpleenABSTRACT
PURPOSE@#The aim of this study was to determine the safety of the carotid artery stenting (CAS) procedure, using an embolic protection device which is based on the presence of unstable plaques on carotid MR imaging in patients who presented with severe carotid artery stenosis.@*MATERIALS AND METHODS@#This prospective study assessed 102 consecutive patients who had been noted with severe carotid stenosis. These patients underwent a preprocedural carotid MR imaging, and a periprocedural diffusion-weighted imaging (DWI) after the CAS. The unstable plaque on the carotid MR imaging was defined as characterized as intraplaque hemorrhage (IPH), thin/ruptured fibrous caps, or ulcers. We analyzed the incidence of the noted periprocedural ipsilateral ischemic events on the DWI, and noted the primary outcomes within 30 days of the CAS.@*RESULTS@#In the study, it is noted that 50 patients (49.0%) had IPH, 84 patients (82.4%) had thin/ruptured fibrous caps, and 43 patients (42.2%) had ulcers as seen on the carotid plaque MR imaging. The IPH was more common in the symptomatic group than in the asymptomatic group (58.7% vs. 41.1%, p = 0.12). Overall, the DWI was positive after CAS in 25.5% of cases. Additionally, the combined rate of 30-day stroke, myocardial infarction, or death was recorded at 3.9%. The new periprocedural ischemic lesions on the DWI were characteristically more frequently observed in the symptomatic group (17/46, 37.0%) than in the asymptomatic group (9/56, 16.1%) (p = 0.03). There was no significant difference in the primary outcome of the CAS, based on the type of unstable plaque of IPH, thin/ruptured fibrous caps, or ulcers.@*CONCLUSION@#The protected CAS appears to be safe, regardless of the noted unstable plaque findings as seen on the carotid MR imaging. In this case, because of the higher risk of periprocedural ipsilateral ischemic events, it is therefore recommended that the symptomatic patients should receive more careful treatment during the CAS placement going forward.
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Pupil-involving oculomotor nerve palsy (ONP) is frequently associated with compressive lesion such as intracranial aneurysm originating from the posterior communicating arteries. Vascular variant of posterior intracranial circulation is regarded as an uncommon cause and association between these vascular variants and intracranial hypertension has not been reported. We present an 18-year-old girl with pupil-involving ONP combined with idiopathic intracranial hypertension who revealed compression of oculomotor nerve by a vascular variant of superior cerebellar artery (SCA). This is a rare case of an ONP attributed to compressive effect from an aberrant SCA affected by intracranial hypertension.
Subject(s)
Adolescent , Female , Humans , Arteries , Intracranial Aneurysm , Intracranial Hypertension , Oculomotor Nerve Diseases , Oculomotor Nerve , Pseudotumor CerebriABSTRACT
OBJECTIVE: To compare the apparent diffusion coefficient (ADC) values of upper abdominal organs with 2 different 3.0 tesla MR systems and to investigate the usefulness of normalization using the spleen. MATERIALS AND METHODS: Forty-one patients were enrolled in this prospective study, of which, 35 patients (M:F, 27:8; mean age ± standard deviation, 62.3 ± 12.3 years) were finally analyzed. In addition to the routine liver MR protocol, single-shot spin-echo echo-planar diffusion-weighted imaging using b values of 0, 50, 400, and 800 s/mm2 in 2 different MR systems was performed. ADC values of the liver, spleen, pancreas, kidney and liver lesion (if present) were measured and analyzed. ADC values of the spleen were used for normalization. The Pearson correlation, Spearman correlation, paired sample t test, Wilcoxon signed rank test and Bland-Altman method were used for statistical analysis. RESULTS: For all anatomical regions and liver lesions, both non-normalized and normalized ADC values from 2 different MR systems showed significant correlations (r = 0.5196-0.8488). Non-normalized ADC values of both MR systems differed significantly in all anatomical regions and liver lesions (p < 0.001). However, the normalized ADC of all anatomical regions and liver lesions did not differ significantly (p = 0.065-0.661), with significantly lower coefficient of variance than that of non-normalized ADC (p < 0.009). CONCLUSION: Normalization of the abdominal ADC values using the spleen as a reference organ reduces differences between different MR systems, and could facilitate consistent use of ADC as an imaging biomarker for multi-center or longitudinal studies.
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Diffusion Magnetic Resonance Imaging , Echo-Planar Imaging , Image Processing, Computer-Assisted , Kidney/diagnostic imaging , Liver/diagnostic imaging , Pancreas/diagnostic imaging , Prospective Studies , Spleen/diagnostic imagingABSTRACT
OBJECTIVE: The purpose of our study was to assess prevalence of carotid intraplaque hemorrhage (IPH) and associations between territorial acute infarction and IPH on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) in patients with acute neurologic symptoms. METHODS: 83 patients with suspected acute neurologic symptoms were evaluated with both brain diffusion weighted imaging (DWI) and carotid MPRAGE sequences. Carotid plaque with high signal intensity on MPRAGE of >200% that of adjacent muscle was categorized as IPH. We analyzed the prevalence of IPH and its correlation with territorial acute infarction. RESULTS: Of 166 arteries, 39 had a carotid artery plaque. Of these arteries, 26 had carotid artery stenosis less than 50%. In all carotid arteries, MR-depicted IPH was found in 7.2% (12/166). High-signal intensity on DWI was found in 17.5% (29/166). Combined lesion with ipsilateral high-signal intensity on DWI and IPH on carotid MPRAGE sequence was found in 6 lesions (6/166, 3.6%). Of patients with carotid artery plaque, MR-predicted IPH was found in 30.8% (12/39) and match lesions with high-signal intensity on DWI and MPRAGE was found in 15.4% (6/39). MR-predicted IPH was significantly higher prevalence in high-grade stenosis group (p=0.010). Relative risk between carotid MPRAGE-positive signal and ipsilateral high-signal intensity on DWI in arteries with carotid artery plaques was 6.8 (p=0.010). CONCLUSION: Carotid MPRAGE-positive signal in patients was associated with an increased risk of territorial acute infarction as detected objectively by brain DWI. The relative risk of stroke was increased in high-grade stenosis categories.
Subject(s)
Humans , Arteries , Atherosclerosis , Brain , Carotid Arteries , Carotid Stenosis , Constriction, Pathologic , Diffusion , Hemorrhage , Infarction , Magnetic Resonance Imaging , Neurologic Manifestations , Prevalence , StrokeABSTRACT
Objective: We investigated whether circle of Willis (COW) morphology on 3D time-of-flight (TOF) MR angiography differs between young normal subjects, older normal subjects, and patients with carotid atherosclerotic plaques. Methods: One hundred seventy-seven subjects were grouped according to age into a young group (20 – 40 years; n = 91) and an older group (> 60 years; n = 86). Subjects underwent brain MR examination as part of a health check-up. Fifty-three patients with carotid atherosclerotic plaque were also included for evaluation in this study. COW morphology on 3D TOF MR angiography was analyzed in terms of completeness or incompleteness of the anterior and posterior components of the circle and completeness of the circle. Results: An incomplete pattern of anterior circulation was significantly more common in carotid atherosclerotic plaque patients (20.7%) than normal older subjects (5.5%) (p < 0.01). A complete posterior circulation pattern was more frequent in normal young subjects (46.5%) than in normal older subjects (16.5%) or the patient group (18.9%) (p < 0.01). Of patients with carotid artery stenosis, 18.9% had a bilateral incomplete connection and were significantly more likely to have an incomplete pattern than normal young (2.3%) or normal older subjects (2.2%) (p < 0.001). Conclusion: Young, healthy subjects were significantly more likely to have a complete pattern of posterior circulation than older subjects. Patients with carotid atherosclerotic plaques were significantly more likely to have incomplete anterior circulation and an incomplete circle than young, normal subjects.
Subject(s)
Circle of WillisABSTRACT
Tumarkin's otolithic crisis refers to drop attacks that are an unusual manifestation of Meniere's disease. It has been proposed that these drop attacks result from mechanical deformation of the otolithic organs related to the endolymphatic hydrops that occurs in Meniere's disease, as revealed by MRI with intratympanic gadolinium enhancement. Here we report a patient with Tumarkin's otolithic crisis in whom inner-ear MRI with intratympanic gadolinium administration during the acute attack did not reveal the presence of endolymphatic hydrops.
Subject(s)
Humans , Endolymphatic Hydrops , Gadolinium , Magnetic Resonance Imaging , Meniere Disease , Otolithic Membrane , SyncopeABSTRACT
Spontaneous intracranial vertebrobasilar dissection can manifest with various clinical symptoms, including subarachnoid hemorrhage or ischemic symptoms from impaired posterior circulation. A 29-year-old woman came to our emergency department with a sudden onset of left sided mild motor weakness and headache. Initial magnetic resonance imaging (MRI) showed mild luminal irregularities in the vertebrobasilar arteries with an eccentric periluminal hematoma. Follow-up MRI obtained 3 days later showed a progression of vertebrobasilar dissection to multifocal stenoses with an increased intramural hematoma.
Subject(s)
Adult , Female , Humans , Arteries , Constriction, Pathologic , Emergency Service, Hospital , Follow-Up Studies , Headache , Hematoma , Magnetic Resonance Imaging , Phenobarbital , Stroke , Subarachnoid HemorrhageABSTRACT
Spindle cell/pleomorphic lipoma is an uncommon benign adipose tissue tumor most frequently arising from the subcutaneous tissue of the back, shoulder, head and neck, and extremities. The deep cervical spaces are the rarely affected locations. Herein we report on the imaging findings of spindle cell/pleomorphic lipoma involving the retropharyngeal space in an elderly woman.
Subject(s)
Aged , Female , Humans , Lipoma/pathology , Pharyngeal Neoplasms/pathologyABSTRACT
Central pontine myelinolysis is a rare neurologic disorder that is defined by demyelination of longitudinally descending tracts and transversly crossing fibers in the basis pontis. Frequently observed clinical manifestations of this disorder include sudden weakness, dysphagia, loss of consciouness and locked-in syndrome. However, there have been a few studies that reported a benign course of this disease, which include cerebellar signs, such as ataxia, intention tremor, and dysarthria. Here we report on a 53-year-old male with a history of liver cirrhosis who showed the cerebellar type of central pontine myelinolysis. The patient was diagnosed with central pontine myelinolysis based on clinical presentations and magnetic resonance imaging findings after a liver transplantation. Conventional magenetic resonance imaging (MRI) revealed the preservation of the corticospinal tract and abnormal pontocerebellar fibers. However, these findings were not sufficient to define the pathophysiology of our patient. Electrophysiologic analysis and diffusion tensor imaging (DTI) were performed to investigate cerebellar signs in this case. Delayed central motor conduction time (CMCT) to the tibialis anterior muscle with transcranial magnetic stimulation (TMS) was observed, which indicated demyelination of the corticospinal tract. Also, diffusion tensor imaging showed abnormal pontocerebellar fibers, which might have been caused by cerebellar dysfunction in our patient. A combination of TMS and DTI was also used to determine the pathophysiology of this disease.
Subject(s)
Humans , Male , Ataxia , Cerebellar Diseases , Deglutition Disorders , Demyelinating Diseases , Diffusion Tensor Imaging , Dysarthria , Liver Cirrhosis , Liver Transplantation , Magnetic Resonance Imaging , Muscles , Myelinolysis, Central Pontine , Nervous System Diseases , Pyramidal Tracts , Quadriplegia , Transcranial Magnetic Stimulation , TremorABSTRACT
PURPOSE: We evaluated which phase was important to recognize local progression of an ablated zone after RFA on multiphase contrast-enhanced MRI (CE-MRI) in patients with unresectable lung malignancy. MATERIALS AND METHODS: Twenty patients who had unresectable lung malignancy underwent multiphase CE-MRI examinations immediately after RFA. We evaluated the enhancement patterns of the ablated zone on multiphase CE-MRI: type I, no enhancement of the ablated zone; type II, enhancement of the ablated margin; type III, heterogeneous enhancement of the ablated zone. We evaluated the association enhancement type with local progression of the ablated zone on the follow up CT using Spearman's ranked test. RESULTS: In complete ablation, the enhancement pattern was types I (11.1%) or II (88.9%). In unsuccessfully treated, type II (57.1%) or III (42.9%) pattern observed in the arterial phase. However, types II (21.4%) and III (78.6%) observed in the venous, and types II (7.1%) and III (92.9%) observed equilibrium phases. Local progression of the ablated zone was associated with the enhancement pattern in equilibrium phases (r=0.8, p < .05). CONCLUSION: Equilibrium phases on multiphase CE-MRI might play a more important role in evaluating an ablated zone for predicting local recurrence after RFA.
Subject(s)
Humans , Follow-Up Studies , Lung , Lung Neoplasms , RecurrenceABSTRACT
Dissection of the middle cerebral artery (MCA) is less frequent compared with dissection of the vertebrobasilar system or carotid artery. Recently, high-resolution cross sectional MR imaging (HRMRI) has emerged as a potential technique for atherosclerotic plaque imaging in MCA. We introduce the findings of HRMRI in a 56-year-old woman with traumatic MCA dissection. HRMRI showed an intimal flap and tapered pseudolumen with intraluminal hemorrhage. We performed stent deployment about MCA dissection after failed medical treatment. Three months later, there was no in-stent restenosis and no further neurological deficit were noted.