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1.
J Clin Neurosci ; 50: 129-131, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29422362

ABSTRACT

Cervical artery dissection is an underrecognized cause of lower cranial neuropathies and diagnosis can remain elusive if not properly investigated. We present a case of an internal carotid artery dissection that was initially missed in a 48-year-old man who presented with subacute-onset of dysarthria, dysphagia, and unilateral tongue weakness. Knowledge of the most common presenting symptoms, relevant neuroanatomy, and neuroimaging techniques is essential to avoid misdiagnosis. Pseudoaneurysm formation from subadventitial carotid artery dissection may result in compressive neuropathies of cranial nerves IX, X, XI, and XII without associated cerebral ischemia. The absence of intraluminal narrowing on CT or MR angiography should not dissuade the clinician; T1-weighted axial cervical MRI with fat-saturation provides the highest sensitivity and specificity to identify these lesions.


Subject(s)
Carotid Artery, Internal, Dissection/complications , Cranial Nerve Diseases/etiology , Aneurysm, False/etiology , Deglutition Disorders/etiology , Dysarthria/etiology , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Nerve Compression Syndromes/etiology
2.
Acta Radiol Open ; 6(11): 2058460117743279, 2017 Nov.
Article in English | MEDLINE | ID: mdl-29225924

ABSTRACT

BACKGROUND: Dental hardware produces streak artifacts on computed tomography (CT) images reconstructed with the standard weighted filtered back projection (wFBP) method. PURPOSE: To perform a preliminary evaluation of an iterative metal artifact reduction (IMAR) technique to assess its ability to improve anatomic visualization over wFBP in patients with dental amalgam or other hardware. MATERIAL AND METHODS: CT images from patients with dental hardware were reconstructed using wFBP and IMAR software and soft-tissue or bone window/level settings. The anatomy most affected by metal artifacts was identified. Two neuroradiologists determined subjective and objective imaging features, including overall metal artifact score (1 = severe artifacts, 5 = no artifacts), soft-tissue visualization score of the most-compromised structure, and artifact length along the skin surface. CT numbers were used to quantify artifact severity. RESULTS: Twenty-four patients were included. IMAR improved overall metal artifact score in 18/24 cases (median =2 ± 0.9 vs. 1 ± 0.6, P < 0.001). Mean CT number in the most-affected anatomical structure significantly improved with IMAR (94.6 vs. 219 HU, P = 0.002) and length of affected skin surface decreased (40.4 mm vs. 118.7 mm, P < 0.001). However, osseous/dental artifactual defects were found in 22/24 cases with IMAR vs. 11/24 with wFBP. CONCLUSION: IMAR software reduced metal artifact both subjectively and objectively and improved visualization of adjacent soft tissues. However, it produced a higher rate of artifactual defects in the teeth and bones than wFBP. Our findings support the use of IMAR as a valuable complement to, but not a replacement for, standard wFBP image reconstruction.

4.
Mayo Clin Proc ; 86(9): 851-6, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21878596

ABSTRACT

OBJECTIVE: To assess the prevalence, clinical presentations, and neuroimaging abnormalities in a series of patients treated for eclampsia at Mayo Clinic in Rochester, MN. PATIENTS AND METHODS: We reviewed the records of all pregnant patients diagnosed as having eclampsia at Mayo Clinic in Rochester, MN, between January 1, 2001, and December 31, 2008. All patients who underwent neuroimaging were identified, and all studies were reviewed by an independent neuroradiologist. Comparisons were made between groups who did and did not undergo imaging to identify differentiating clinical or laboratory variables. RESULTS: Thirteen cases of eclampsia were found, with neuroimaging studies available for 7: magnetic resonance imaging (n=6) and computed tomography (n=1). All 7 patients developed eclamptic seizures, and 2 of 7 patients had severe hypertension, with recorded systolic blood pressures exceeding 180 mm Hg. Neuroimaging showed characteristic changes of posterior reversible encephalopathy syndrome (PRES) in all patients. Follow-up imaging showed resolution in 2 of 3 patients; 1 patient had residual neuroimaging abnormalities. CONCLUSION: Our results suggest that the clinical syndrome of eclampsia is associated with an anatomical substrate that is recognizable by neuroimaging as PRES. The levels of blood pressure elevation are lower than those reported in cases of PRES because of hypertensive encephalopathy. Further studies are needed to determine whether more aggressive blood pressure control and early neuroimaging may have a role in the management of these patients.


Subject(s)
Eclampsia/diagnosis , Eclampsia/therapy , Hypertensive Encephalopathy/diagnosis , Hypertensive Encephalopathy/therapy , Prenatal Diagnosis/methods , Adult , Blood Pressure , Brain Mapping , Female , Humans , Hypertensive Encephalopathy/complications , Medical Records/statistics & numerical data , Pregnancy , Retrospective Studies , Risk Factors , Syndrome
5.
AJR Am J Roentgenol ; 194(2): W193-201, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20093573

ABSTRACT

OBJECTIVE: The purpose of our study was to evaluate the dose and image quality performance of a dedicated cone-beam CT (CBCT) scanner in comparison with an MDCT scanner. MATERIALS AND METHODS: The conventional dose metric, CT dose index (CTDI), is no longer applicable to CBCT scanners. We propose to use two dose metrics, the volume average dose and the mid plane average dose, to quantify the dose performance in a circular cone-beam scan. Under the condition of equal mid plane average dose, we evaluated the image quality of a CBCT scanner and an MDCT scanner, including high-contrast spatial resolution, low-contrast spatial resolution, noise level, CT number uniformity, and CT number accuracy. RESULTS: For the sinus scanning protocol, the CBCT system had comparable high-contrast resolution and inferior low-contrast resolution to those obtained with the MDCT scanner when the doses were matched (mid plane average dose 9.2 mGy). The CT number uniformity and accuracy were worse on the CBCT scanner. The image artifacts caused by beam hardening and scattering were also much more severe on the CBCT system. CONCLUSION: With a matched radiation dose, the CBCT system for sinus study has comparable high-contrast resolution and inferior low-contrast resolution relative to the MDCT scanner. Because of the more severe image artifacts on the CBCT system due to the small field of view and the lack of accurate scatter and beam-hardening correction, the utility of the CBCT system for diagnostic tasks related to soft tissue should be carefully assessed.


Subject(s)
Cone-Beam Computed Tomography/instrumentation , Cone-Beam Computed Tomography/methods , Head , Tomography, X-Ray Computed/instrumentation , Tomography, X-Ray Computed/methods , Humans , Phantoms, Imaging , Radiation Dosage
6.
J Digit Imaging ; 20(2): 105-13, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17505869

ABSTRACT

In this study, we present preliminary data on the effect of automated 3D image alignment on the time to arrive at a decision about an imaging finding, the agreement of multiple of multiple observers, the prevalence of comparison examinations, and technical success rates for the image alignment algorithm. We found that automated image alignment reduced the average time to make a decision by 25% for cases where the structures are rigid, and when the scanning protocol is similar. For cases where these are not true, there is little or no benefit. In our practice, 54% of cases had prior examinations that could be automatically aligned. The overall benefit seen in our department for highly similar exams might be 20% for neuro and 10% for body; the benefit seen in other practices is likely to vary based on scanning practices and prevalence of prior examinations.


Subject(s)
Decision Making , Diagnostic Imaging , Image Interpretation, Computer-Assisted/methods , Radiology , Algorithms , Data Display , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging , Radiology Information Systems , Time Factors , Tomography, X-Ray Computed
7.
J ECT ; 23(1): 36-7, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17435574

ABSTRACT

Electroconvulsive therapy (ECT) is often considered relatively contraindicated in patients with intracranial space-occupying lesions, especially those with increased intracranial pressure, edema, or mass effect. We describe the safe use of ECT in 6 patients with arachnoid cysts. We conclude that such lesions are probably not associated with increased morbidity in ECT but that neurological evaluation pretreatment is indicated.


Subject(s)
Arachnoid Cysts/complications , Electroconvulsive Therapy , Mental Disorders/therapy , Adult , Contraindications , Female , Humans , Male , Middle Aged
9.
Radiographics ; 26(1): 115-24, 2006.
Article in English | MEDLINE | ID: mdl-16418247

ABSTRACT

Many anatomic structures of the middle and inner ear are not optimally depicted at computed tomography (CT) with image reconstruction in the standard axial and coronal planes. Recent advances in multidetector CT, including the development of scanners with 32 detector rows, allow the acquisition of isotropic voxels that can be reconstructed in any plane of section. This technique gives radiologists the opportunity to visualize the anatomic structures of the middle and inner ear (the ossicular chain, stapedial footplate-oval window complex, round window, cochlea, vestibular aqueduct, and bones of the superior semicircular canal and facial nerve canal) in greater detail and may help increase the accuracy of CT for the diagnosis of diseases of the middle and inner ear.


Subject(s)
Ear Diseases/diagnostic imaging , Ear, Inner/diagnostic imaging , Ear, Middle/diagnostic imaging , Image Processing, Computer-Assisted , Tomography, X-Ray Computed/methods , Humans , Temporal Bone/diagnostic imaging
10.
Neurology ; 65(3): 486-8, 2005 Aug 09.
Article in English | MEDLINE | ID: mdl-16087925
12.
AJNR Am J Neuroradiol ; 24(8): 1615-7, 2003 Sep.
Article in English | MEDLINE | ID: mdl-13679281

ABSTRACT

We describe a case demonstrating reversible MR imaging findings, including diffusion-weighted imaging changes in association with metronidazole (Flagyl) toxicity. The diagnosis of metronidazole toxicity was made clinically and supported by the MR imaging findings. Quantitative apparent diffusion coefficient (ADC) maps demonstrated edema with associated increased ADC values within the dentate nuclei of the cerebellum on initial imaging. Follow-up imaging performed 8 weeks after cessation of metronidazole therapy demonstrated resolution of imaging findings, including diffusion changes.


Subject(s)
Abdominal Abscess/drug therapy , Abdominal Neoplasms/secondary , Anti-Infective Agents/toxicity , Carcinoid Tumor/secondary , Cerebellar Ataxia/chemically induced , Diffusion Magnetic Resonance Imaging , Drug Therapy, Combination/toxicity , Dysarthria/chemically induced , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Metronidazole/toxicity , Neurotoxicity Syndromes/diagnosis , Abdominal Neoplasms/complications , Aged , Amoxicillin/administration & dosage , Anti-Infective Agents/administration & dosage , Carcinoid Tumor/complications , Cerebellar Ataxia/diagnosis , Cerebellar Nuclei/drug effects , Cerebellar Nuclei/pathology , Dose-Response Relationship, Drug , Drug Administration Schedule , Drug Therapy, Combination/administration & dosage , Dysarthria/diagnosis , Follow-Up Studies , Humans , Male , Metronidazole/administration & dosage , Ofloxacin/administration & dosage , Remission, Spontaneous
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