Magnetic resonance imaging findings of redundant nerve roots of the cauda equina

BACKGROUND Redundant nerve roots(RNRs)of the cauda equina are often a natural evolutionary part of lumbar spinal canal stenosis secondary to degenerative processes characterized by elongated,enlarged,and tortuous nerve roots in the superior and/or inferior of the stenotic segment.Although magnetic resonance imaging(MRI)findings have been defined more frequently in recent years,this condition has been relatively under-recognized in radiological practice.In this study,lumbar MRI findings of RNRs of the cauda equina were evaluated in spinal stenosis patients.AIM To evaluate RNRs of the cauda equina in spinal stenosis patients.METHODS One-hundred and thirty-one patients who underwent lumbar MRI and were found to have spinal stenosis between March 2010 and February 2019 were included in the study.On axial T2-weighted images(T2WI),the cross-sectional area(CSA)of the dural sac was measured at L2-3,L3-4,L4-5,and L5-S1 levels in the axial plane.CSA levels below 100 mm^2 were considered stenosis.Elongation,expansion,and tortuosity in cauda equina fibers in the superior and/or inferior of the stenotic segment were evaluated as RNRs.The patients were divided into two groups:Those with RNRs and those without RNRs.The CSA cut-off value resulting in RNRs of cauda equina was calculated.Relative length(RL)of RNRs was calculated by dividing the length of RNRs at mid-sagittal T2WI by the height of the vertebral body superior to the stenosis level.The associations of CSA leading to RNRs with RL,disc herniation type,and spondylolisthesis were evaluated.RESULTS Fifty-five patients(42%)with spinal stenosis had RNRs of the cauda equina.The average CSA was 40.99±12.76 mm^2 in patients with RNRs of the cauda equina and 66.83±19.32 mm^2 in patients without RNRs.A significant difference was found between the two groups for CSA values(P<0.001).Using a cut-off value of 55.22 mm^2 for RNRs of the cauda equina,sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)values of 96.4%,96.1%,89.4%,and 98.7%were obtained,respectively.RL was 3.39±1.31(range:0.93-6.01).When the extension of RNRs into the superior and/or inferior of the spinal canal stenosis level was evaluated,it was superior in 54.5%,both superior and inferior in 32.8%,and inferior in 12.7%.At stenosis levels leading to RNRs of the cauda equina,29 disc herniations with soft margins and 26 with sharp margins were detected.Disc herniation type and spondylolisthesis had no significant relationship with RL or CSA of the dural sac with stenotic levels(P>0.05).As the CSA of the dural sac decreased,the incidence of RNRs observed at the superior of the stenosis level increased(P<0.001).CONCLUSION RNRs of the cauda equina are frequently observed in patients with spinal stenosis.When the CSA of the dural sac is<55 mm^2,lumbar MRIs should be carefully examined for this condition.

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors(SGTs)make up a small portion(approximately 5%)of all head and neck tumors.Most of them are located in the parotid glands,while they are less frequently located in the submandibular glands,minor salivary glands or sublingual gland.The incidence of malignant or benign tumors(BTs)in the salivary glands varies according to the salivary gland from which they originate.While most of those detected in the parotid gland tend to be benign,the incidence of malignancy increases in other glands.The use of magnetic resonance imaging(MRI)in the diagnosis of SGTs is increasing every day.While conventional sequences provide sufficient data on the presence,localization,extent and number of the tumor,they are insufficient for tumor specification.With the widespread use of advanced techniques such as diffusion-weighted imaging,semiquantitative and quantitative perfusion MRI,studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes.With diffusion MRI,differentiation can be made by utilizing the cellularity and microstructural properties of tumors.For example,SGTs such as high cellular Warthin’s tumor(WT)or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors.Contrast agent uptake and wash-out levels of tumors can be detected with semiquantitative perfusion MRI.For example,it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out.On quantitative perfusion MRI studies using perfusion parameters such as Ktrans,Kep,and Ve,it is reported that WTs can show higher Kep and lower Ve values than other tumors.In this study,the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.

Radiological imaging findings of scheuermann disease

AIM To find accompanying anomalies of typical and atypical Scheuermann's disease(SD) is reported in the present study. METHODS Study included 20 patients(16 men and 4 women) who had radiological imaging radiography, magnetic resonance imaging(MRI) and computed tomography, if available, due to back pain, curved back and low back pain in November 2011-February 2016 period. Patients were categorized into typical and atypical patterns based on the region involved. Thoracic kyphosis values were measured using real Cobb angle. Accompanying disc degeneration, herniations and spinal cord pathologies were studied using MRI.RESULTS Age of the patients ranged from 11.0 to 23.0(mean 17.2 ± 3.0). Typical pattern of SD were detected in 15 patients while atypical pattern were detected in 5 patients. Cobb angle range was 40.2-67.2(mean 55.5 ± 8.7) in typical Scheuermann's patients and 24.7-49.9(mean 36.7 ± 10.8) in atypical ones. Intervertebral level was affected and had the measures of 3-8(mean 5.3 ± 1.6) and 7-9(mean 8.2 ± 0.8) in typical and atypical Scheuermann's patients, respectively. Level of degenerative disc disease in MRI was 1-7 discs(mean 4.1 ± 1.7) in typical patients and 5-10 discs(mean 7.6 ± 1.9) in atypical patients.CONCLUSION SD can be seen in typical and atypical patterns, typical being more frequent. Because degenerative disc diseases,herniations and cord pathologies such as syringomyelia can accompany SD(albeit more common in atypical pattern), it is necessary to evaluate these patients with plain radiography and MRI together.

Evaluation of ischemic lesions after carotid artery stenting with diffusion-weighted imaging

BACKGROUND Almost 90%of cerebral thromboembolism cases are caused by atherosclerosis.Craniocervical atherosclerosis is often observed at the carotid bifurcation and is responsible for 20%-30%of all stroke cases.The course of atherosclerotic carotid artery stenosis varies depending on the grade of stenosis and characteristics of the plaque.Carotid artery stenting(CAS)can be used as a less invasive method in patients with symptomatic and asymptomatic high-grade carotid artery stenosis.Diffusion-weighted imaging(DWI)is an effective method for detection of silent or symptomatic acute ischemic lesions that may arise due to CAS or carotid endarterectomy.The number and volume of new ischemic lesions are determined using DWI.AIM To evaluate the number and volume of ischemic lesions and their cerebral parenchymal and vascular distribution after CAS using DWI.METHODS Forty-seven male(73.4%)and seventeen female(26.6%)patients(total,n=64)aged 42-84 years(mean 67.96±8.03 years)diagnosed with carotid stenosis between October 2006 and July 2012 were included in this retrospective study.Twelve of the cases(18.8%)were asymptomatic,while fifty-two(81.2%)were symptomatic.The area where the stenosis was highest was measured,and the stenosis rate was determined using the North American Symptomatic Carotid Endarterectomy Trial method.DWI of the cases was evaluated by two radiologists experienced in neuroradiology(B.A.with more than 15 years of experience,E.G.with more than 10 years of experience).Routine DWI examinations were carried out by a 1.5 T MR device 1 h before and after the operation.Since the ischemic lesions that developed in the first hour and in the follow-up period of 5-24 h were assumed to be due to CAS,all lesions within the first 24 h were considered as new ischemias.RESULTS In the present study,39 new ischemic lesions were detected in 20 cases.The average number of new lesions after all CAS operations was 0.62.They were mostly located in the occipital lobes,followed by the frontal and parietal lobes.These new ischemic lesions were most common in the middle cerebral artery territory,followed by the posterior cerebral artery territory and middle cerebral artery-posterior cerebral artery watershed areas.New lesions were found in 31.2%(20/64)of patients,including 17(26.5%)in ipsilateral and three(4.6%)in contralateral hemispheres.New bilateral lesions were detected in one case(1.5%).The average volume of the new ischemic lesions detected by the two observers was 1.10 cm³.The numbers of newly appearing ischemic lesions in DWI after CAS were significantly higher in cases where stenting was applied on the left side of the carotid artery and in cases where longer plaques(>1 cm)were responsible for the narrowing in symptomatic patients.The stenosis rate was low in the group with ulcerated plaques.CONCLUSION New ischemic lesions due to CAS appear mostly in the main arterial territory but they may also occur in watershed areas.

Diagnostic efficacy of diffusion-weighted imaging and semiquantitative and quantitative dynamic contrast-enhanced magnetic resonance imaging in salivary gland tumors

BACKGROUND Increased use of functional magnetic resonance imaging(MRI)methods such as diffusion-weighted imaging(DWI)and dynamic contrast-enhanced(DCE)MRI consisting of sequential contrast series,allows us to obtain more information on the microstructure,cellularity,interstitial distance,and vascularity of tumors,which has increased the discrimination power for benign and malignant salivary gland tumors(SGTs).In the last few years,quantitative DCE MRI data containing T1 perfusion parameters(K_(trans),K_(ep)and V_(e)),were reported to contribute to the differentiation of benign or malignant subtypes in SGTs.AIM To evaluate the diagnostic efficacy of DWI and semiquantitative and quantitative perfusion MRI parameters in SGTs.METHODS Diffusion MRI[apparent diffusion coefficient(ADC)value]with a 1.5 T MR machine,semiquantitative perfusion MRI[time intensity curve(TIC)pattern],and quantitative perfusion MRI examinations(K_(trans),K_(ep)and V_(e))of 73 tumors in 67 patients with histopathological diagnosis performed from 2017 to 2021 were retrospectively evaluated.In the ADC value and semiquantitative perfusion MRI measurements,cystic components of the tumors were not considered,and the region of interest(ROI)was manually placed through the widest axial section of the tumor.TIC patterns were divided into four groups:Type A=T_(peak)>120 s;type B=T_(peak)≤120 s,washout ratio(WR)≥30%;type C=T_(peak)≤120 s,WR<30%;and type D=flat TIC.For the quantitative perfusion MRI analysis,a 3D ROI was placed in the largest solid component of the tumor,and the K_(trans),K_(ep)and V_(e)values were automatically generated.RESULTS The majority of SGTs were located in the parotid glands(86.3%).Of all the SGTs,68.5%were benign and 31.5%were malignant.Significant differences were found for ADC values among pleomorphic adenomas(PMAs),Warthin's tumors(WTs),and malignant tumors(MTs)(P<0.001).PMAs had type A and WTs had type B TIC pattern while the vast majority of MTs and other benign tumors(OBTs)(54.5%and 45.5%,respectively)displayed type C TIC pattern.PMAs showed no washout,while the highest mean WR was observed in WTs(59%±11%).K_(trans)values of PMAs,WTs,OBTs,and MTs were not significantly different.K_(ep)values of PMAs and WTs were significantly different from those of OBTs and MTs.Mean V_(e)value of WTs was significantly different from those of PMAs,OBTs,and MTs(P<0.001).CONCLUSION The use of quantitative DCE parameters along with diffusion MRI and semiquantitative contrastenhanced MRI in SGTs could improve the diagnostic accuracy.

Evaluation of pineal cysts with magnetic resonance imaging

AIM To evaluate radiological imaging findings of patients who had been found to have pineal cyst(PC) in brain magnetic resonance imaging(MRI).METHODS A total of 9546 patients who had brain MRI examination in March 2010-January 2018 period were studied.Fiftysix patients(44 female and 12 male) found to have PC were evaluated.Eighteen of the patients had had follow-up examinations of 2-94 mo(mean 30.50 ± 28.83).PC dimensions and volume,radiological imaging features(signal intensities,contours,internal septationloculation and contrast-enhancement features) and natural history in cases who had been followed-up were evaluated by two radiologists.RESULTS Of 9546 patients,5555 were female(58.2%) and 3991 male(41.8%).Age range was 1-99(mean 43.18 ± 20.94).PC frequency was calculated to be 0.58%.Forty-four of the 56 patients(78.57%) with PC were female and 12 male(21.43%),and their age range was 5-61(mean 31.26 ± 12.73).Thirty-five of the PCs were typical(62.50%) and 21(37.50%) were atypical.No significant difference was found between initial and final imaging sizes of PCs which were monitored by follow-up examinations(P > 0.05).CONCLUSION PCs are cysts which do not show clear size and natural changes and are more frequently observed in females and in adult ages.Most of them are isointense with cerebrospinal fluid on T1 and T2 A weighted images,hyperintense compared to cerebrospinal fluid on fluidattenuated inversion recovery; sequence and smoothly contoured.Their typical forms have peripheral rim and multilocular ones may have septal contrast-enhancement.