Assessment for Carotid Atherosclerotic Plaque Using Vessel Wall Magnetic Resonance Imaging: A Multireader ROC Study to Determine Optimal Sequence for Detecting Vessel Wall Calcification.

INTRODUCTION: We aimed to compare conventional vessel wall MR imaging techniques and quantitative susceptibility mapping (QSM) to determine the optimal sequence for detecting carotid artery calcification. METHODS: Twenty-two patients who underwent carotid vessel wall MR imaging and neck CT were enrolled. Four slices of 6-mm sections from the bilateral internal carotid bifurcation were subdivided into 4 segments according to clock position (0-3, 3-6, 6-9, and 9-12) and assessed for calcification. Two blinded radiologists independently reviewed a total of 704 segments and scored the likelihood of calcification using a 5-point scale on spin-echo imaging, FLASH, and QSM. The observer performance for detecting calcification was evaluated by a multireader, multiple-case receiver operating characteristic study. Weighted κ statistics were calculated to assess interobserver agreement. RESULTS: QSM had a mean area under the receiver operating characteristic curve of 0.85, which was significantly higher than that of any other sequence (p < 0.01) and showed substantial interreader agreement (κ = 0.68). A segment with a score of 3-5 was defined as positive, and a segment with a score of 1-2 was defined as negative; the sensitivity and specificity of QSM were 0.75 and 0.87, respectively. CONCLUSION: QSM was the most reliable MR sequence for the detection of plaque calcification.

Significance of Low Signal in Intracranial Vertebral Artery Wall Observed on Susceptibility-Weighted Angiography.

PURPOSE: We aimed to investigate the clinical significance of the low signal in the intracranial vertebral artery wall observed on susceptibility-weighted angiography. MATERIALS AND METHODS: We retrospectively reviewed susceptibility-weighted angiographies from 200 consecutive patients with acute ischemic stroke in the posterior circulation territory. The presence of eccentric or concentric low signals in the vertebral artery wall was examined and evaluated. The etiology of the low signal was also investigated as much as possible by referring to computed tomography and T1-weighted imaging (T1WI). We also compared its frequency in each stroke subtype. RESULTS: A low signal was observed in 128/200 patients (64%). The low signals (58%) corresponded to vessel wall calcification in 74 of 128 patients and to vessel wall thickening showing intermediate to low (n = 8) or high (n = 16) signals on T1WI in 24 (19%) patients. The low signal did not have vessel wall thickening or calcification in 1 patient, and the cause of the low signal could not be verified in 29 patients. According to stroke subtypes, a low signal was observed in 14/14 (100%) vertebral artery dissections, all of which corresponded to intramural hematoma. A low signal was observed in 51/65 (78%) atherothromboses, which were significantly more frequent than cardioembolism (34/66; 52%) and small-artery disease (18/39; 46%) (p < 0.01). In atherothrombosis, calcification was the most common cause of low signal (n = 32; 63%). CONCLUSION: Low signals on susceptibility-weighted angiography were frequently observed in vertebral artery dissection and atherothrombosis, reflecting intramural hematoma in all of the former and predominantly calcification in the latter.

Amide proton transfer MRI differentiates between progressive multifocal leukoencephalopathy and malignant brain tumors: a pilot study.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nerve system caused by the John Cunningham virus. On MRI, PML may sometimes appear similar to primary central nervous system lymphoma (PCNSL) and glioblastoma multiforme (GBM). The purpose of this pilot study was to evaluate the potential of amide proton transfer (APT) imaging for differentiating PML from PCNSL and GBM. METHODS: Patients with PML (n = 4; two men; mean age 52.3 ± 6.1 years), PCNSL (n = 7; four women; mean age 74.4 ± 5.8 years), or GBM (n = 11; 6 men; mean age 65.0 ± 15.2 years) who underwent APT-CEST MRI between January 2021 and September 2022 were retrospectively evaluated. Magnetization transfer ratio asymmetry (MTRasym) values were measured on APT imaging using a region of interest within the lesion. Receiver operating characteristics curve analysis was used to determine diagnostic cutoffs for MTRasym. RESULTS: The mean MTRasym values were 0.005 ± 0.005 in the PML group, 0.025 ± 0.005 in the PCNSL group, and 0.025 ± 0.009 in the GBM group. There were significant differences in MTRasym between PML and PCNSL (P = 0.023), and between PML and GBM (P = 0.015). For differentiating PML from PCNSL, an MTRasym threshold of 0.0165 gave diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of 100% (all). For differentiating PML from GBM, an MTRasym threshold of 0.015 gave diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 90.9%, 80.0%, and 100%, respectively. CONCLUSION: MTRasym values obtained from APT imaging allowed patients with PML to be clearly discriminated from patients with PCNSL or GBM.

Quantitative Chemical Exchange Saturation Transfer Imaging of Amide Proton Transfer Differentiates between Cerebellopontine Angle Schwannoma and Meningioma: Preliminary Results.

Vestibular schwannomas are the most common tumor at the common cerebellopontine angle, followed by meningiomas. Differentiation of these tumors is critical because of the different surgical approaches required for treatment. Recent studies have demonstrated the utility of amide proton transfer (APT)-chemical exchange saturation transfer (CEST) imaging in evaluating malignant brain tumors. However, APT imaging has not been applied in benign tumors. Here, we explored the potential of APT in differentiating between schwannomas and meningiomas at the cerebellopontine angle. We retrospectively evaluated nine patients with schwannoma and nine patients with meningioma who underwent APT-CEST MRI from November 2020 to April 2022 pre-operation. All 18 tumors were histologically diagnosed. There was a significant difference in magnetization transfer ratio asymmetry (MTRasym) values (0.033 ± 0.012 vs. 0.021 ± 0.004; p = 0.007) between the schwannoma and meningioma groups. Receiver operative curve analysis showed that MTRasym values clearly differentiated between the schwannoma and meningioma groups. At an MTRasym value threshold of 0.024, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive values for MTRasym were 88.9%, 77.8%, 80.0%, and 87.5%, respectively. Our results demonstrated the ability of MTRasym values on APT-CEST imaging to discriminate patients with schwannomas from patients with meningiomas.

Human immunodeficiency virus-associated vacuolar encephalomyelopathy with granulomatous-lymphocytic interstitial lung disease improved after antiretroviral therapy: a case report.

BACKGROUND: Vacuolar encephalomyelopathy, a disregarded diagnosis lately, was a major neurological disease in the terminal stages of human immunodeficiency virus (HIV)-1 infection in the pre-antiretroviral therapy (ART) era. Granulomatous-lymphocytic interstitial lung disease (GLILD) was classically identified as a non-infectious complication of common variable immunodeficiency; however, it is now being recognized in other immunodeficiency disorders. Here, we report the first case of GLILD accompanied by vacuolar encephalomyelopathy in a newly diagnosed HIV-infected man. CASE PRESENTATION: A 40-year-old Japanese man presented with chronic dry cough and progressing paraplegia. Radiological examination revealed diffuse pulmonary abnormalities in bilateral lungs, focal demyelinating lesions of the spinal cord, and white matter lesions in the brain. He was diagnosed with GLILD based on marked lymphocytosis detecting in bronchoalveolar lavage, and transbronchial-biopsy proven T-cellular interstitial lung disease with granulomas. Microbiological examinations did not reveal an etiologic agent. The patient was also diagnosed with HIV-associated vacuolar encephalomyelopathy on the basis of an elevated HIV viral load in cerebrospinal fluid. After initiating ART, the brain lesions and paraplegia improved significantly, and interstitial abnormalities of the lungs and cough disappeared. CONCLUSION: This report highlights that even in the post-ART era in developed countries with advanced healthcare services, HIV-associated vacuolar encephalomyelopathy should be considered in the differential diagnosis of a progressive neurological disorder during the first visit. Furthermore, GLILD may represent an HIV-associated pulmonary manifestation that can be treated by ART.

A homozygous splice site ROBO1 mutation in a patient with a novel syndrome with combined pituitary hormone deficiency.

The genetic causes of combined pituitary hormone deficiency remain elusive in most patients. Recently, incompletely penetrant heterozygous mutations in ROBO1 have been described in patients with pituitary stalk interruption syndrome. Herein, we identified a novel homozygous slice site mutation in ROBO1 (c.1342+1G>A) using a trio whole-exome sequencing strategy in a 5-year-old Japanese boy who had combined pituitary hormone deficiency, psychomotor developmental delay, severe intellectual disability, sensorineural hearing loss, strabismus, and characteristic facial features, including a broad forehead, micrognathia, and arched eyebrows. Magnetic resonance imaging delineated anterior pituitary hypoplasia, ectopic posterior pituitary, invisible pituitary stalk, thinning of the corpus callosum, and hypoplasia of the pons and midbrain. The phenotypically normal parents (first cousins) were heterozygous for the mutation. The results provide further evidence of ROBO1 being involved in the development of the pituitary gland. A recessive mutation of ROBO1 is a potential novel cause of a syndromic disorder associated with combined pituitary hormone deficiency.

Arterial Spin Labeling Magnetic Resonance Imaging Can Identify the Occlusion Site and Collateral Perfusion in Patients with Acute Ischemic Stroke: Comparison with Digital Subtraction Angiography.

BACKGROUND AND OBJECTIVES: Determining the occlusion site and collateral blood flow is important in acute ischemic stroke. The purpose of the current study was to test whether arterial spin labeling (ASL) magnetic resonance imaging (MRI) could be used to identify the occlusion site and collateral perfusion, using digital subtraction angiography (DSA) as a gold standard. METHOD: Data from 521 consecutive patients who presented with acute ischemic stroke at our institution from January 2012 to September 2014 were retrospectively reviewed. Image data were included in this study if: (1) the patient presented symptoms of acute ischemic stroke; (2) MRI was performed within 24 h of symptom onset; and (3) DSA following MRI was performed (n = 32 patients). We defined proximal intra-arterial sign (IAS) on ASL as enlarged circular or linear bright hyperintense signal within the occluded artery and distal IAS as enlarged circular or linear bright hyperintense signals within arteries inside or surrounding the affected region. The presence or absence of the proximal IAS and distal IAS were assessed, along with their inter-rater agreement and consistency with the presence of occlusion site and collateral flow on DSA images. RESULTS: The sensitivity and specificity for identifying occlusion site with ASL were 82.8 and 100%, respectively. Those for identifying collateral flow with ASL were 96.7 and 50%, respectively. The inter-rater reliability was excellent for proximal IAS (κ = 0.92; 95% CI 0.76-1.00) and substantial for distal IAS detection (κ = 0.78; 95% CI 0.38-1.00). CONCLUSIONS: Proximal IAS and distal IAS on ASL imaging can provide important diagnostic clues for the detection of arterial occlusion sites and collateral perfusion in patients with acute ischemic stroke.

[Middle Cerebral Artery Fenestration with M2 Fusion Detected during Aneurysm Clipping:A Case Report].

We report a unique case of middle cerebral artery fenestration with M2 fusion detected during an aneurysm clipping. A 72-year-old woman was diagnosed with an unruptured aneurysm of the right middle cerebral artery, and middle cerebral artery fenestration with M2 fusion was detected during the aneurysm clipping surgery. It was difficult to identify this unusual vascular anomaly before the surgery. Therefore, neurosurgeons should be cautious of such hidden vascular anomalies and be prepared for the possible complications during surgery.

Early Diagnosis of Infective Endocarditis by Brain T2*-Weighted Magnetic Resonance Imaging.

BACKGROUND: Because infective endocarditis (IE) carries a high risk of morbidity and mortality, rapid diagnosis and effective treatment are essential to achieving a good patient outcome. However, the diagnosis of IE is often difficult in patients presenting with nonspecific clinical manifestations. An association between IE and hypointense signal spots on brain T2*-weighted magnetic resonance imaging (MRI) has been reported, but the clinical significance remains unclear.Methods and Results:To assess the clinical importance of silent lesions in the brains of IE patients, hypointense signal spots detected on their brain T2*-weighted MRI scans were investigated in a retrospective review of 44 consecutive patients with definite or suspected IE evaluated by MRI between June 2006 and January 2014. Hypointense signal spots on T2*-weighted MRI were detected in 37 (84%) patients; of these, 21 (46%) had ischemic lesions, 10 (22%) had subarachnoid hemorrhage, 4 (9%) had intraparenchymal hemorrhage, and 4 (9%) had infectious aneurysm. The hypointense signal spots on T2*-weighted images were preferentially distributed in cortical areas. CONCLUSIONS: T2*-weighted hypointense signal spots are highly frequent in patients with IE and their presence may be informative in the monitoring of IE-associated brain lesions, even those that are neurologically asymptomatic. The strong association between IE and T2*-weighted hypointense signal spots supports the need to consider additional criteria in the diagnosis of IE.

[A Case of Moyamoya Disease Associated with SAPHO Syndrome].

Moyamoya disease is a unique occlusive disease of the internal carotid artery(ICA)with moyamoya vessels that can lead to transient ischemic attacks and hemorrhagic stroke. When other inherited or acquired disorders and conditions occur in conjunction with moyamoya disease, the syndrome is known as quasi-moyamoya disease. We report the case of a 34-year-old woman with a past history of SAPHO(Synovitis-Acne-Pustulosis-Hyperostosis-Osteomyelitis)syndrome, who presented with arm weakness and headache. Magnetic resonance angiography revealed severe terminal stenosis of the left ICA with moyamoya vessels, and she was diagnosed as moyamoya disease associated with SAPHO syndrome. She underwent superficial temporal artery-middle cerebral artery anastomosis and her arm weakness improved postoperatively. Postoperative course was uneventful, although she showed transient right paresthesia, which improved with conservative therapy. Autoimmune response could contribute to the development of this moyamoya disease, and we discuss its mechanism with a literature review.

Point-by-point parent artery/sinus obliteration using detachable, pushable, 0.035-inch coils.

BACKGROUND: Parent artery occlusion for intractable aneurysms or sinus packing for dural arteriovenous fistulas (DAVFs) is sometimes difficult and requires many expensive coils to accomplish complete occlusion. To help solve these problems, we reviewed our experience using 0.035-inch coil (0.035 coil; Boston Scientific, San Leandro, CA, USA), which has been used in cardiovascular and abdominal lesions. METHODS: These 0.035 coils were preferably used in addition to the detachable and fibered coils for patients with intractable aneurysms, traumatic vessel blowout, and DAVF. Our strategy was as follows: (1) detachable coils were deployed first for the ideal anchoring of the coils; (2) small fibered coils were additionally deployed to stabilize the coil mass; (3) 0.035 coils were deployed to complete the occlusion. RESULTS: From January 2012 to December 2013, seven consecutive patients were treated by endovascular embolization with 0.035 coils. Reasons for intervention were parent artery occlusion for carotid blowout (n = 1), internal carotid artery aneurysm (n = 2), traumatic vertebral artery injury (n = 2), vertebral AVF (n = 1), and transverse sinus-sigmoid sinus DAVF (n = 1). In our cases, a mean of 20.1 ± 8.5 coils per vessel were placed, and mean total coil length was 258.4 ± 91.5 cm per vessel. All procedures were safely performed and complete occlusions achieved. CONCLUSIONS: From our initial experience and treatment results, we believe endovascular parent artery occlusion or sinus packing with 0.035 coils to be useful in terms of reducing the number and expense of coils and also accomplishing immediate occlusion.

De novo ivy sign indicates postoperative hyperperfusion in moyamoya disease.

BACKGROUND AND PURPOSE: The ivy sign on fluid-attenuated inversion recovery MRI is a specific finding in moyamoya disease (MMD). This sign indicates decreased cerebral perfusion, dilated pial vasculature, and slow leptomeningeal collateral flow. This study aimed to clarify the characteristics of perioperative changes in the ivy sign in relation to cerebral hyperperfusion, which frequently occurs in MMD of unknown pathogenesis. METHODS: This prospective study included patients with MMD who underwent superior temporal artery-middle cerebral artery single bypass. Fluid-attenuated inversion recovery MRI was performed to evaluate the appearance of the ivy sign in the ipsilateral hemisphere preoperatively and on postoperative days 2 and 30. The ivy sign was assessed in combination with perioperative symptoms and cerebral hemodynamics using single-photon emission computed tomography. RESULTS: Of 42 consecutive patients (55 sides) who underwent bypass surgery, 32 (58.2%) showed an increase in the ivy sign (de novo ivy sign) on postoperative day 2; this had disappeared by day 30. Interestingly, these 32 patients had a significantly higher incidence of hyperperfusion on single-photon emission computed tomography and hyperperfusion syndrome, and there was no correlation between the de novo ivy sign and a preoperative ivy sign or the preoperative cerebral hemodynamics. In multivariate analysis, a de novo ivy sign was significantly correlated with postoperative hyperperfusion. CONCLUSIONS: In MMD, a de novo ivy sign could indicate postoperative hyperperfusion after bypass, which is not always correlated with preoperative hemodynamic impairment. Additional factors other than preoperative cerebral hemodynamics might be involved in postoperative hyperperfusion in MMD.

A case of iliac artery injury treated by covered stent during carotid artery stenting.

Here we describe a case of iliac artery injury during carotid artery stenting (CAS) treated by covered stent. A 74-year-old man underwent CAS for asymptomatic right carotid artery stenosis. Under local anesthesia, the right common femoral artery was punctured and an 8 Fr long sheath introducer was placed. However, the sheath kinked because the iliac artery was tortuous. We introduced the stylet to the sheath again and tried to extend the kinking. It failed, and the arterial dissection was identified at the lateral iliac artery. The kink was extended with triple coaxial system, i.e. guidewire, coaxial catheter, and a guiding catheter; CAS was performed with distal filter protection. Before removal of the sheath, the right iliac artery was examined, and extraversation of the contrast medium was observed. The balloon catheter was placed to the lesion and dilated for the hemostasis. However, it failed, and the covered stent was placed subsequently. Although blood tests revealed anemia and CT showed retroperitoneal hematoma after the treatment, further complication did not occur. Treatment with covered stent for the vessel injury was effective.

Pathophysiology of flow impairment during carotid artery stenting with an embolus protection filter.

OBJECTIVE: Carotid artery stenting (CAS) is a well-accepted treatment for atherosclerotic stenosis of carotid arteries. Since the occurrence of distal embolization with CAS is still a major concern embolus protection devices (EPD) are usually employed during the procedure. We examined two types of embolus protection filters (Angioguard XP (AG); Filterwire EZ (FW)) and evaluated the function. Thus, the filter was examined postoperatively and the cause of intraoperative flow impairment was evaluated. MATERIALS AND METHODS: CAS was performed for 54 patients with carotid artery stenosis (55 lesions: 25 AG; 27 FW; 3 others). After completing CAS the filter membrane was stained with hematoxylin-eosin (HE) solution and removed from the filter strut. Once mounted on a glass slide the filter was evaluated under a microscope. The area occupied with debris was measured and the relationship to intraoperative flow impairment was evaluated. Furthermore, the relationship between perioperative ischemic complications and intraoperative flow impairment was statistically analyzed. RESULTS: Microscopic observation of the slide revealed the pore density of the FW was 1.5 times higher than that of the AG and the filter area of the FW was 2.5 times wider than than the AG. HE staining facilitated characterization of the debris composition. The area occupied with debris was significantly more in the AG (0.241 ± 0.13 cm(2)) than in the FW (0.129 ± 0.093 cm(2)). Thus, fibrin was significantly more precipitated in the AG. Flow impairment occurred in 6 AG cases (24.0 %) and 4 FW cases (14.8 %). It was induced by filter obstruction in the AG and by vasospasms in the FW. Three cases treated with AG (12.0 %) were complicated with cerebral infarction and all of them were related to flow impairment. One FW case (3.7 %) was complicated with cerebral infarction in presence of preserved flow throughout the intervention. CONCLUSION: Filter function is different according to each design. The cause of flow impairment was attributable to filter obstruction in the AG group and to vasospasms in the FW group. Filter obstruction tends to result in cerebral infarction.

[Carotid blowout syndrome treated by parent artery occlusion using pushable coils: a case report].

OBJECTIVE: Here we report a case of carotid blowout syndrome (CBS) treated with parent artery occlusion using pushable coils. CASE PRESENTATION: A 68-year-old man with a history of surgery and chemoradiation therapy for esophageal cancer 9 years prior presented with a massive hemorrhage from a skin defect in the neck. Angiography revealed encasement of the right common carotid artery by radiation necrosis, and CBS was diagnosed. We performed emergent endovascular treatment, and the right common carotid artery was occluded using pushable coils and a detachable coil. The patient's postoperative course was uneventful. However, he died of esophageal cancer recurrence 6 months later. CONCLUSION: Pushable coils were useful for occluding the parent artery in this case of CBS.

[Carotid artery stenting with proximal and distal protection for radiation-induced carotid stenosis: a case report].

Here we report a case of radiation-induced carotid stenosis treated with carotid artery stenting and proximal and distal protection. A 62-year-old man with a history of radiation therapy for cervical malignant lymphoma at 31 years of age was diagnosed with left radiation-induced carotid stenosis. Angiography revealed left common carotid artery severe stenosis, and T1-weighted magnetic resonance imaging showed plaque hyperintensity. He was treated with carotid artery stenting and proximal and distal protection. Postoperative carotid ultrasonography showed moderate dilatation of the left common carotid artery and his postoperative course was uneventful. Carotid artery stenting and proximal and distal protection for radiation-induced carotid stenosis may be an effective treatment.

Quantitative evaluation of pulmonary hypertension using 4D flow MRI: A retrospective study.

Background: Pulmonary hypertension (PH) is a severe vascular disorder that may affect 50 % of patients with heart failure. Currently, right-sided heart catheterization is required to definitively diagnose PH. However, this method is invasive and thus may not be appropriate for repeated, long-term monitoring of PH patients. This retrospective study's aim was to evaluate whether 4D flow magnetic resonance imaging (MRI) can be used to quantitively measure flow parameters to identify patients with PH. Methods: The study cohort included 97 patients recruited from a single institution and divided into three groups based on echocardiographic estimate of pulmonary artery systolic pressure (PASP): normal group with PASP<36 mmHg, borderline PH group with PASP of 37-50 mmHg, and PH group with PASP>50 mmHg. 4D flow MRI was used to quantitively assess blood flow and velocity, regurgitation, wall shear stress (WSS) and kinetic energy in the pulmonary artery trunk, right main pulmonary artery, and left pulmonary artery. Two experienced radiologists independently analyzed the MR images, blinded to clinical details. Results: We found a significant difference in WSS in the pulmonary artery trunk, right main pulmonary artery and left main pulmonary artery among the three patient groups. We also found significant differences in the kinetic energy and average through velocity in the pulmonary artery trunk and right main pulmonary artery, and significant differences in the flow rate in the right main pulmonary artery. Conclusion: These data suggest that 4D flow MRI can quantitate pulmonary artery flow parameters and distinguish between patients with and without PH.

Measurement of carotid stenosis using duplex ultrasonography with a microconvex array transducer: a validation with cerebral angiography.

BACKGROUND: We aimed to evaluate the validity of duplex ultrasonography (DUS) using a microconvex array transducer (MAT) with enhanced flow imaging (EFI) for visualization of the distal, internal carotid artery (ICA) and the accurate assessment of ICA stenosis. METHODS: Patients who underwent both DUS and digital subtraction angiography (DSA) were registered for this study. DUS was performed by using a linear array transducer (LAT) and an MAT with EFI. The visibility of the ICA was compared between the 2 transducers. ICA stenosis was evaluated by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method on DUS, and the peak systolic flow velocity (PSV) was evaluated by using an MAT. These results were compared with DSA. RESULTS: In 238 internal carotid arteries, the average length of visualized ICA was longer for DUS using an MAT than an LAT (38.7±11.7 mm versus 25.8±9.8 mm, P<.0001). In 68 stenotic, internal carotid arteries, the degree of ICA stenosis detected by the NASCET method on DUS was correlated to that on DSA (P<.0001, r=.969, and adjusted r2=.938). PSV also correlated to NASCET method on DSA (P<.0001, r=.804, and adjusted r2=.640). CONCLUSIONS: DUS using an MAT with EFI technology could reveal more extended distal views of the ICA and was strongly correlated with NASCET method on DSA.

Amide Proton Transfer-Chemical Exchange Saturation Transfer Imaging of Intracranial Brain Tumors and Tumor-like Lesions: Our Experience and a Review.

Chemical exchange saturation transfer (CEST) is a molecular magnetic resonance imaging (MRI) method that can generate image contrast based on the proton exchange between labeled protons in solutes and free, bulk water protons. Amide proton transfer (APT) imaging is the most frequently reported amide-proton-based CEST technique. It generates image contrast by reflecting the associations of mobile proteins and peptides resonating at 3.5 ppm downfield from water. Although the origin of the APT signal intensity in tumors is unclear, previous studies have suggested that the APT signal intensity is increased in brain tumors due to the increased mobile protein concentrations in malignant cells in association with an increased cellularity. High-grade tumors, which demonstrate a higher proliferation than low-grade tumors, have higher densities and numbers of cells (and higher concentrations of intracellular proteins and peptides) than low-grade tumors. APT-CEST imaging studies suggest that the APT-CEST signal intensity can be used to help differentiate between benign and malignant tumors and high-grade gliomas and low-grade gliomas as well as estimate the nature of lesions. In this review, we summarize the current applications and findings of the APT-CEST imaging of various brain tumors and tumor-like lesions. We report that APT-CEST imaging can provide additional information on intracranial brain tumors and tumor-like lesions compared to the information provided by conventional MRI methods, and that it can help indicate the nature of lesions, differentiate between benign and malignant lesions, and determine therapeutic effects. Future research could initiate or improve the lesion-specific clinical applicability of APT-CEST imaging for meningioma embolization, lipoma, leukoencephalopathy, tuberous sclerosis complex, progressive multifocal leukoencephalopathy, and hippocampal sclerosis.

Impact of width of susceptibility vessel sign on recanalization following endovascular therapy.

BACKGROUND AND PURPOSE: We aimed to investigate the relationship between arterial recanalization following endovascular therapy and the susceptibility vessel sign (SVS) length and width on susceptibility-weighted imaging. METHODS: We retrospectively evaluated consecutive patients with anterior circulation ischemic stroke who underwent magnetic resonance imaging preceded endovascular therapy, and measured the SVS length and width. Successful recanalization was defined as expanded thrombolysis in cerebral infarction grade of 2b to 3. Logistic regression analysis was executed to determine the independent predictors of successful recanalization and first-pass reperfusion (FPR) after endovascular therapy. RESULTS: Among 100 patients, successful recanalization and FPR were observed in 77 and 34 patients, respectively. The median SVS length and width were 10.3 mm (interquartile range, 6.8-14.1 mm) and 4.2 mm (interquartile range, 3.1-5.2 mm), respectively. In multivariate logistic regression analysis, SVS width was associated with successful recanalization (odds ratio, 1.88; 95% confidence interval, 1.14-3.07; p = 0.005) and FPR (odds ratio, 1.38; 95% confidence interval, 1.01-1.89; p = 0.039). The optimal cutoff value for the SVS width to predict successful recanalization and FPR were 4.2 mm and 4.0 mm, respectively. CONCLUSIONS: Larger SVS width may predict successful recanalization and FPR following endovascular therapy.