Unenhanced Brain CT Research Articles

Assessment of a New CT Detector and Filtration Technology: Part 2-Image Quality in Phantoms, Cadavers, and Patients.

The purpose of this work was to evaluate the image quality of a commercial CT scanner equipped with a novel detector and filtration technology called PureVision Optics (PVO). CT number, noise, contrast-to-noise ratio (CNR), modulation transfer function (MTF), and noise power spectrum (NPS) were assessed using the ACR CT Accreditation phantom scanned with various acquisitions at 80 kV, 100 kV, 120 kV, and 135 kV, each with multiple CTDIvol values of 20 mGy, 40 mGy, and 65 mGy. Artifacts were evaluated in an anthropomorphic head phantom, a cadaver head, and in patient studies. Two neuroradiologists assessed image quality features in various patients who were examined with unenhanced brain CT on both scanners. Compared with the conventional scanner, for the same CTDIvol, the PVO scanner produced 20.3% less image noise (P < 0.001), 18.9% higher CNR (P < 0.01), and 24.6% higher spatial resolution (P < 0.001). Streak artifacts were less severe with the PVO scanner for the phantom, cadaver, and patient scans (P < 0.05). Radiologists scored the PVO scanner as significantly better for visualization of the cerebrospinal fluid space over the cerebral sulci in high convexity, image noise in gray and white matter, and artifacts in the posterior fossa. They also significantly preferred the PVO scanner for visualization of the border between brain gray and white matter, cerebrospinal fluid space around the mesencephalon, and overall diagnostic acceptability. For matched CTDIvol values, the scanner equipped with PVO technology produced better objective and subjective image quality metrics in brain CT imaging compared with a conventional CT scanner without PVO. In clinical settings, PVO may allow for lower doses while enhancing imaging through dense areas, improving visualization of subtle details, and offering more effective options for examining obese patients.This research received financial support from Canon Medical Systems USA. The study design and data were fully controlled by the coauthors, of which none are employees or consultants of Canon Medical Systems USA.

Waldenstrom Macroglobulinemia Recurrence with Bing–Neel Syndrome Presentation

Bing–Neel syndrome (BNS) is a rare condition that may occur in patients with Waldenstrom macroglobulinemia (WM) and is caused by lymphoplasmacytic infiltration into the central nervous system. BNS is an extramedullary manifestation of WM which may present with various neurological signs and symptoms that make the diagnosis difficult to achieve. We present a case of BNS in a 60-year-old patient diagnosed 6 years after recovering from Waldenstrom’s macroglobulinemia. We observed the patient for a secondary generalized focal motor seizure. Unenhanced brain CT revealed slight hyperdensity of left parietal subarachnoid spaces. The MRI of the brain and spinal cord showed leptomeningeal enhancement in both parietal lobes. The presence of monoclonal bands (light chain k and IgM) was found in cerebrospinal fluid, leading to the diagnosis of BNS. The patient started treatment with ibrutinib and remains clinically stable during a 1-year follow-up. However, the MRI showed the appearance of a new subcortical left parietal lesion. BNS is an extremely rare presentation of WM that should be recognized and considered early in the presence of unexplained neurological symptoms in patients with a history of WM, even if the patient appears to have recovered.

Analysis of image quality and radiation dose in routine adult brain helical and wide-volume computed tomography procedures

ObjectivesTo evaluate and compare image quality and radiation dose between the helical and wide-volume scans to determine the protocol that provides a lower radiation dose without loss in image quality. MethodsThe study was prospectively conducted on consented adult patients that presented for routine brain CT. Image quality and radiation dose were compared between the helical and wide-volume scans on the Toshiba 160-slice Aquilion Prime CT scanner. The volume computed tomography dose index (CTDIvol) and dose length product (DLP) for each scan mode were collected and compared. Image quality was quantitatively and qualitatively evaluated using the unenhanced brain CT images. The data were analysed using a statistical package for social sciences (SPSS) software version 20 for both the descriptive and inferential statistics. A significant difference in image quality and radiation dose between the helical and wide-volume scans was determined based on a p-value of <0.05. ResultsA total of 54 participants were included, with two groups of 27 participants. The CTDIvol and DLP values were significantly p < 0.05 higher in the helical scan (CTDIvol: 65 mGy; DLP: 1597 mGy.cm) compared to the wide-volume scan (CTDIvol: 54 mGy; DLP: 1133 mGy.cm). The grey and white matters show a better signal-to-noise ratio (SNR) for the helical scan. Meanwhile, the contrast-to-noise ratio (CNR) was significantly p < 0.05 higher in the wide-volume scan. The results from the visual grading methods were compared and showed superior image quality in helical over the wide-volume scan. ConclusionWide-volume provides a lower dose compared to helical and therefore, could be adopted as the routine protocol for brain CT for in house dose optimisation. Where clinical conditions warrant the need for a helical scan, the protocol should be optimised in line with the as low as reasonable achievable (ALARA) principle.

Thin Slice Unenhanced Brain CT Can Detect Aneurysms Larger than 7 mm.

Purpose:To evaluate the detection rate of intracranial aneurysms on reconstructed thin slice non enhanced CT (NECT) scans.Methods:NECT scans from 34 patients with 35 aneurysms and 35 individuals without aneurysms were collected. Thin slice maximum intensity projections of the NECT scans were reconstructed. One observer evaluated the native images twice with a time interval of six month between both passes with respect to the prevalence and location of an aneurysm. The size and location of the aneurysms were evaluated in corresponding CT-Angiography and Time of flight datasets. A logit regression analysis was performed with size and location as dependent variables. 2 × 2 tables were constructed. The sensitivity and false negative rate were calculated for aneurysms with 0–6.9 mm, 7–9.9 mm and 10–20 mm and the under the curve (AUC) was calculated.Results:The overall detection rate of the aneurysms was 63% for the first pass and 66% for the second pass in the reconstructed NECT scans. The detection rate of aneurysms is size dependent. The sensitivity to detect aneurysms with a size of 0–6.9 mm was 0.09 and 0.03, for aneurysms with a size of 7–9.9. mm was 0.8 and 0.7 and for aneurysms with a size of 10–20 mm was 0.92 for both passes.The AUC was 0.77 for the first pass and 0.78 for the second pass.Conclusions:NECT scans can be used to detect a significant proportion of intracranial aneurysms larger than 7 mm if properly displayed and reconstructed. These patients should receive further vascular imaging to prevent future aneurysm related subarachnoid hemorrhage.

Stroke Mimics in the Acute Setting: Role of Multimodal CT Protocol.

Ischemic stroke can be mimicked by nonischemic conditions. Due to emphasis on the rapid treatment of acute ischemic stroke, it is crucial to identify these conditions to avoid unnecessary therapies and potential complications. We investigated the performance of the multimodal CT protocol (unenhanced brain CT, CTA, and CTP) to discriminate stroke mimics from acute ischemic stroke. We retrospectively selected multimodal CT studies performed for clinical suspicion of acute ischemic stroke in our center in a 24-month period, including patients with at least 1 follow-up imaging study (brain CT or MR imaging). Hemorrhagic strokes were excluded. We measured the performance of multimodal CT, comparing the original diagnostic results with the final clinical diagnosis at discharge. Among 401 patients, a stroke mimic condition was diagnosed in 89 (22%), including seizures (34.8%), migraine with aura attack (12.4%), conversion disorder (12.4%), infection (7.9%), brain tumor (7.9%), acute metabolic condition (6.7%), peripheral vertigo (5.6%), syncope (5.6%), transient global amnesia (3.4%), subdural hematoma (1.1%), cervical epidural hematoma (1.1%), and dural AVF (1.1%). Multimodal CT sensitivity, specificity, and accuracy were 24.7%, 99.7%, and 83%. Multimodal CT revealed peri-ictal changes in 13/31 seizures and diagnosed 7/7 brain tumors, 1/1 dural AVF, and 1/1 subdural hematoma. CT perfusion played a pivotal diagnostic role. Multimodal CT demonstrated low sensitivity but high specificity in the diagnosis of stroke mimics in the acute setting. The high specificity of multimodal CT allows ruling out stroke and thereby avoiding unnecessary revascularization treatment in patients with diagnosis of a stroke mimic.

Acute Severe Bilateral Visual Loss as Presenting Symptom of COVID-19 Infection

Introduction: Coronavirus disease 2019 (COVID-19) has emerged as a pandemic and is accompanied by extraordinary morbidity and mortality. Critically ill COVID-19 patients have frequent thrombotic problems and laboratory evidence of hypercoagulability. The spectrum of presentations and complications of COVID-19 is still evolving. We describe a patient with unusual visual symptoms as the presenting signs of COVID-19. Case Presentation: In this case report, we describe a patient who presented with acute severe bilateral visual loss and headache. On neurological examination, cranial nerves were normal. There was no motor and sensorial abnormality. While the patient was in the emergency room, he was tested positive for COVID-19 via nasopharyngeal swab polymerase chain reaction (PCR) as part of COVID-19 surveillance. An unenhanced brain CT scan showed infarction in the occipital cortex bilaterally due to ischemic stroke involving the Posterior Cerebral Artery (PCA). A few hours later, oxygen saturation was 42%, and a sudden decline of consciousness was observed, progressing to coma. The neurosurgery intervention failed to change the patient's status, and he was pronounced dead in the next few hours. Conclusions: This case illuminates a wide range of COVID-19-related symptomatology and highlights the need for clinicians to be aware of different clinical appearances associated with this infection.

Accuracy of unenhanced CT in the diagnosis of cerebral venous sinus thrombosis.

To evaluate the diagnostic performance of unenhanced brain CT (NECT) in identifying patients with cerebral venous sinus thrombosis (CVT). Forty-eight consecutive patients with CVT and 48 healthy controls were included in our retrospective study. All patients underwent NECT and CT/MR angiography within 24h. Two radiologists independently evaluated NECT images for the presence of sinus hyperdensity; discrepancies were solved by consensus. Sinus attenuation was measured in seven sites. The obtained data were compared with the presence of CVT at CT/MR angiography and with patients' hematocrit. Interobserver agreement in sinus hyperdensity detection was good (k = 0.64). The presence of sinus hyperdensity at NECT enabled to detect patients with CVT with 81% sensitivity, 77% specificity, 78% PPV, and 80% NPV. Mean attenuation was significantly higher in sinus segments involved by CVT than in patent ones (62.4 ± 10 versus 55.6 ± 6 HU, p < 0.0001). ROC analysis showed that a cutoff value of 63HU enables to detect patients with CVT with 52% sensitivity and 88% specificity. Hematocrit values were significantly correlated with patent sinus segments attenuation (r = 0.19). The presence of sinus hyperdensity at NECT enables to detect patients with CVT with 81% sensitivity and 77% specificity. A sinus attenuation cutoff value of 63HU can be used in order to increase specificity, but lowering sensitivity.

Imaging of Neurologic Disease in Hospitalized Patients with COVID-19: An Italian Multicenter Retrospective Observational Study.

Of 725 consecutive hospitalized patients with coronavirus disease 2019, 108 (15%) had acute neurologic symptoms necessitating neurologic imaging.

Cranial falling bullet injuries, a series of 30 cases in Iraq

Purpose: The purpose of this study is to highlight the importance of cranial falling bullet injuries and raise awareness about them. We studied the clinical and radiological findings, and their relation to the treatment and outcome. There are limited studies in this field.Materials and methods: Thirty patients, (aged 8–55 years) with cranial falling bullet injury were included in this study. They were followed during their hospitalization and up to 6 months thereafter. Post-resuscitation clinical findings, unenhanced brain CT scan findings, treatment and outcome (Glasgow Outcome Scale) were studied.Results: Male to female ratio was (1.73:1). Median age of all patients was: 17.5 years. 20(66.7%) patients had a GCS of 13–15, 3(10%) had 9–12, 2(6.7%) had 6–8, and 5(16.6%) had 3–5 at presentation. 23(76.7%) patients had normal pupillary reaction and symmetry whereas 7(23.3%) had poor reaction and/or asymmetry. On CT scan, 13 had a unilobar injury, six had multilobar or bihemispheric injuries, 10 had a bullet through the deep midline structures of the brain, seven had transventricular with IVH, four had SAH, none had large intracranial hematomas. All patients received medical treatment. Local wound care and/or extraction of extracranial subgaleal bullets were performed in 24 patients (80%). More extensive surgery was performed in six patients (20%). There was significant correlation (using Correlation Coefficient) between GCS, pupillary reaction/symmetry and CT imaging findings with the patient outcome. Low GCS, poor pupillary reaction and/or asymmetry, CT findings of central area injury, transventricular, IVH, or multilobar injury were associated with poor outcome.Conclusions: Cranial falling bullet injuries are uncommon, but they can cause significant morbidity and mortality. More studies are needed to document the impact of these injuries and to raise awareness among the society to support the efforts aiming at controlling the irrational use of guns in different countries of the world.

Et si l’imagerie neurologique nous était expliquée ?

Brain CT Perfusion (CTP) is an X-ray imaging technique for the assessment of brain tissue perfusion, which can be used in several different entities. The aim of this study is the evaluation of the radiation dose to patients during a comprehensive brain CT prescription protocol (CPP) consisting of an unenhanced brain CT, a brain CT angiography and a CTP scan.Eighteen patients were studied using an 80-slice CT system, with an iterative reconstruction algorithm. The volume Computed Tomography Dose Index (CTDIvol) and dose length product (DLP) were recorded from the dose report of the system. The calculation of effective dose (ED) was accomplished using the DLP values.For the CTP examinations, the CTDIvol ranged from 116.0 to 134.8 mGy, with the mean value 119.5 mGy. The DLP ranged from 463.9 to 539.2 mGy·cm, with the mean value 478 mGy·cm. For the CPP, the total ED ranged from 3.31 to 5.07 mSv, with the mean value 4.37 mSv.These values are lower than the values reported in corresponding studies, including studies utilizing CT systems with more slices.

Prevalence and vascular risk factors of basal ganglia calcifications in patients at risk for cerebrovascular disease

Background and purposeRisk factors for and meaning of basal ganglia calcifications outside Fahr syndrome are poorly understood. We aimed to assess the prevalence of basal ganglia calcifications and the association with vascular risk factors. Materials and methods1133 patients suspected of acute ischemic stroke from the Dutch acute stroke (DUST) study who underwent thin-slice unenhanced brain CT were analyzed. Basal ganglia calcifications were scored bilaterally as absent, mild (dot), moderate (multiple dots or single artery) and severe (confluent). Uni- and multivariable logistic regression analysis was used to determine possible risk factors (age, gender, history of stroke, smoking, hypertension, diabetes mellitus, hyperlipidemia, body mass index (BMI), renal function and family history of cardiovascular disease under 60 years) for presence of basal ganglia calcifications and ordinal regression analysis for severity of basal ganglia calcifications. ResultsMean age was 67.4 years (SD: 13.8), 56.8% were male. 337 (29.7%) patients had basal ganglia calcifications, of which 196 (58%) were mild, 103 (31%) moderate, 38 (11%) severe. In multivariable logistic regression analysis, age (OR: 1.02, 95% CI 1.01–1.03, P < 0.01) and BMI (OR: 0.95, 95% CI 0.91–0.98, p 0.01) were significantly associated with the presence of basal ganglia calcifications. Ordinal regression analysis gave comparable results. Age (OR: 1.02, 95% CI 1.01–1.03, P < 0.01) and BMI (OR: 0.95, 95% CI 0.92–0.99, P 0.01) were significantly associated with severity of basal ganglia calcifications. ConclusionsIn this study with patients suspected of acute ischemic stroke, basal ganglia calcifications were common and significantly associated with older age and lower BMI.

Trombosis de senos venosos durales: análisis clínico y neuroradiológico de 10 casos consecutivos en el hospital México entre enero y diciembre del 2013.

La trombosis de senos venosos durales (TSVD) es una emergencia neurológica poco común y potencialmente mortal. Su incidencia anual se estima entre 2-7 casos por millón de habitantes. La oclusión repentina de un seno venoso por un trombo causa un incremento agudo de la presión intracraneal provocando hipertensión intracraneal. Debido a la ruptura de venas corticales tanto hemorragia cerebral parenquimatosa como hemorragia subaracnoidea pueden estar presentes en el TAC de cerebro sin contraste. Su diagnóstico puede ser un reto. Una alta sospecha clínica se requiere para su diagnóstico temprano. Actualmente con el uso de la venografía por TAC o por RM su diagnóstico es menos difícil. La mayoría de los pacientes se recuperan sin ninguna lesión neurológica residual. En TVSD el inicio rápido de la anticoagulación es mandatoria para repermeabilizar el seno venoso ocluido. Ni la hemorragia cerebral parenquimatosa ni la hemorragia subaracnoidea contraindican la anticoagulación. Se describen las principales características demográficas, factores de riesgo, hallazgos clínicos, características neuroradiológicas, tratamiento y evolución de 10 pacientes consecutivos con el diagnóstico de TVSD en un único hospital público de Costa Rica.

Patient dose in brain perfusion imaging using an 80-slice CT system

Background and purposeBrain CT Perfusion (CTP) is an X-ray imaging technique for the assessment of brain tissue perfusion, which can be used in several different entities. The aim of this study is the evaluation of the radiation dose to patients during a comprehensive brain CT prescription protocol (CPP) consisting of an unenhanced brain CT, a brain CT angiography and a CTP scan. Materials and methodsEighteen patients were studied using an 80-slice CT system, with an iterative reconstruction algorithm. The volume Computed Tomography Dose Index (CTDIvol) and dose length product (DLP) were recorded from the dose report of the system. The calculation of effective dose (ED) was accomplished using the DLP values. ResultsFor the CTP examinations, the CTDIvol ranged from 116.0 to 134.8mGy, with the mean value 119.5mGy. The DLP ranged from 463.9 to 539.2mGy·cm, with the mean value 478mGy·cm. For the CPP, the total ED ranged from 3.31 to 5.07mSv, with the mean value 4.37mSv. ConclusionsThese values are lower than the values reported in corresponding studies, including studies utilizing CT systems with more slices.

Dual-energy CT of the brain: Comparison between DECT angiography-derived virtual unenhanced images and true unenhanced images in the detection of intracranial haemorrhage.

To evaluate the diagnostic performance of virtual non-contrast (VNC) images in detecting intracranial haemorrhages (ICHs). Sixty-seven consecutive patients with and 67 without ICH who underwent unenhanced brain CT and DECT angiography were included. Two radiologists independently evaluated VNC and true non-contrast (TNC) images for ICH presence and type. Inter-observer agreement for VNC and TNC image evaluation was calculated. Sensitivity and specificity of VNC images for ICH detection were calculated using Fisher's exact test. VNC and TNC images were compared for ICH extent (qualitatively and quantitatively) and conspicuity assessment. On TNC images 116 different haemorrhages were detected in 67 patients. Inter-observer agreement ranged from 0.98-1.00 for TNC images and from 0.86-1.00 for VNC images. VNC sensitivity ranged from 0.90-1, according to the different ICH types, and specificity from 0.97-1. Qualitatively, ICH extent was underestimated on VNC images in 11.9% of cases. Haemorrhage volume did not show statistically significant differences between VNC and TNC images. Mean haemorrhage conspicuity was significantly lower on VNC images than on TNC images for both readers (p < 0.001). VNC images are accurate for ICH detection. Haemorrhages are less conspicuous on VNC images and their extent may be underestimated. • VNC images represent a reproducible tool for detecting ICH. • ICH can be identified on VNC images with high sensitivity and specificity. • Intracranial haemorrhages are less conspicuous on VNC images than on TNC images. • Intracranial haemorrhages extent may be underestimated on VNC images.

Adaptive statistical iterative reconstruction reduces patient radiation dose in neuroradiology CT studies

Adaptive statistical iterative reconstruction (ASIR) can decrease image noise, thereby generating CT images of comparable diagnostic quality with less radiation. The purpose of this study is to quantify the effect of systematic use of ASIR versus filtered back projection (FBP) for neuroradiology CT protocols on patients' radiation dose and image quality. We evaluated the effect of ASIR on six types of neuroradiologic CT studies: adult and pediatric unenhanced head CT, adult cervical spine CT, adult cervical and intracranial CT angiography, adult soft tissue neck CT with contrast, and adult lumbar spine CT. For each type of CT study, two groups of 100 consecutive studies were retrospectively reviewed: 100 studies performed with FBP and 100 studies performed with ASIR/FBP blending factor of 40 %/60 % with appropriate noise indices. The weighted volume CT dose index (CTDIvol), dose-length product (DLP) and noise were recorded. Each study was also reviewed for image quality by two reviewers. Continuous and categorical variables were compared by t test and free permutation test, respectively. For adult unenhanced brain CT, CT cervical myelography, cervical and intracranial CT angiography and lumbar spine CT both CTDIvol and DLP were lowered by up to 10.9 % (p < 0.001), 17.9 % (p = 0.005), 20.9 % (p < 0.001), and 21.7 % (p = 0.001), respectively, by using ASIR compared with FBP alone. Image quality and noise were similar for both FBP and ASIR. We recommend routine use of iterative reconstruction for neuroradiology CT examinations because this approach affords a significant dose reduction while preserving image quality.

CT Density Measurement and H:H Ratio Are Useful in Diagnosing Acute Cerebral Venous Sinus Thrombosis

Brain CT is widely used to exclude or confirm acute cerebral venous sinus thrombosis. The purpose of this study was to assess the value of attenuation measurement and the H:H ratio on unenhanced brain CT scans in the diagnosis of acute cerebral venous sinus thrombosis. This retrospective study evaluated 20 patients with acute cerebral venous sinus thrombosis and 20 age- and sex-matched control participants without thrombosis. Three experienced observers independently evaluated the unenhanced brain CT scan for the presence of cerebral venous sinus thrombosis and measured the attenuation in the dural sinuses. Interreader differences were examined, as well as densities and H:H ratio between patients with acute cerebral venous sinus thrombosis and control participants. A significant difference in the average sinus attenuation was found between patients with acute cerebral venous sinus thrombosis (73.9 ± 9.2 HU) and the control group (52.8 ± 6.7 HU; P < .0001). A similar difference was found for the H:H ratio (1.91 ± 0.32 vs 1.33 ± 0.12 in patients with and without cerebral venous sinus thrombosis, respectively; P < .0001). Optimal thresholds of 62 HU and 1.52 lead to accuracies of 95% for average sinus attenuation and 97.5% for the H:H ratio, respectively. Hyperattenuation and the H:H ratio in the dural sinuses on unenhanced brain CT scans have a high accuracy in the detection of acute cerebral venous sinus thrombosis.

Cerebral sinovenous thrombosis in pediatric practice

Cerebral sinovenous thrombosis (CSVT) in the pediatric population is a relatively uncommon yet under-appreciated and potentially life-threatening neurological condition. Early symptoms and signs are often vague and the clinician requesting a cranial imaging study might not even suspect sinovenous thrombosis. If left undiagnosed, or if the diagnosis of CSVT is delayed, progressive neurological deterioration, coma and death can follow. The purpose of this review is to highlight pertinent development of the cerebral venous system, discuss the causal factors of cerebral sinovenous thrombosis in the pediatric population, review practical imaging strategies using cranial sonography augmented with color and pulsed Doppler, unenhanced brain CT, CT venography, cerebral MRI, and MR venography (MRV). Finally, this review will illustrate the imaging features of sinovenous thrombosis, including a discussion of the common causes of false-positive and false-negative CT and MRI studies.

Basilar artery thrombosis: imaging and endovascular therapy

Basilar artery thrombosis represents a rare type of ischaemic stroke with a mortality rate of 80%-90% if not promptly treated. The aim of our study was to review our experience with computed tomography angiography (CTA) in the diagnosis of basilar artery thrombosis and its treatment with endovascular procedures. Our retrospective study is based upon 59 nontrauma patients with episodes of sudden loss of consciousness. Patients were investigated using unenhanced brain CT followed by intracranial CTA (16-slice CT) when no parenchymal haemorrhage was detected. Patients with a CTA diagnosis of basilar artery thrombosis were considered for endovascular treatment. CTA accuracy was evaluated by considering the 12 patients who underwent endovascular angiography (the gold standard). The success of endovascular therapy was evaluated by considering the degree of microcirculatory reperfusion. After the exclusion of 33 patients affected by parenchymal or subarachnoid haemorrhage, the final study consisted of 26 patients who underwent CTA. Basilar artery thrombosis was diagnosed in 15 of them, and 12 were treated at our institution. The comparison between CTA and endovascular angiography showed 100% agreement in evaluating occlusion site and extension. Seven patients underwent intra-arterial lysis, and five underwent mechanical clot removal. CTA, with its wide availability and rapid execution times, is the most indicated examination in the case of suspected basilar artery thrombosis. Although there is a lack of randomised controlled prospective studies suggesting the most appropriate therapeutic approach to basilar artery thrombosis, our study lends weight to the role of interventional neuroradiology in the treatment of this condition.

Isolated cortical vein thrombosis - the cord sign.

Isolated cortical vein thrombosis is an uncommon condition and often difficult to diagnose, both clinically and radiologically. We report a case of a 38 years old man who presented with headache of new onset and clinical examination was unremarkable. The unenhanced brain CT did not reveal any abnormality. In view of unrelenting headache and partial seizures, we performed magnetic resonance imaging (with axial T1, T2 and gradient echo sequences, coronal FLAIR, diffusion weighted imaging as well as Gadolinium contrast-enhanced images) and magnetic resonance venography of the brain that revealed an isolated parietal cortical vein thrombosis with the rarely reported 'cord sign'. We report the clinical and radiological findings in our patient with isolated parietal cortical vein thrombosis.

CT angiography versus colour-Doppler US in acute dissection of the vertebral artery

Conventional digital subtraction angiography (DSA) still represents the criterion standard for the diagnosis of vertebral artery dissection (VAD), but the main drawbacks of this technique include invasiveness, patient discomfort and risk of complications. We evaluated the potential of multidetector computed tomography angiography (CTA) as a noninvasive tool providing high-resolution images of the arterial lumen and wall by comparing the diagnostic accuracy of CTA and colour-Doppler ultrasonography (CDUS) in detecting acute VAD. We retrospectively reviewed 15 cases of VAD in 15 patients (five men and ten women, age range 28-58 years) who came to our attention between August 2001 and September 2005. The diagnosis was made on the basis of appropriate clinical presentation, absence of atherosclerotic disease in the cerebrovascular circulation and evidence of distinctive CT features, which were subsequently confirmed by conventional angiography used as reference standard. All patients with a clinical suspicion of VAD underwent CDUS of the neck vessels prior to CTA. Accuracy, sensitivity and specificity of CDUS and CTA were expressed as percentages of agreement with the reference angiographic procedure. Interreader concordance for detection of VAD by CTA was calculated with the Cohen K value. The CDUS examinations revealed ten out of 15 VAD, with a sensitivity of 66%, a specificity of 60%, a positive predictive value of 55.5% and a negative predictive value of 70.5%. In five cases, CDUS revealed nonspecific wall and flow alterations; in eight patients, high resistance obstructive flow; and in two patients, intimal flap with demonstration of the true and false lumen. CTA enabled the correct identification of all 15 VAD. The reported sensitivity, specificity, positive predictive value and negative predictive value were 100%, 95%, 93.7% and 100%, respectively. With regard to localisation of VAD, CTA showed 100% correlation with DSA. The differences in CTA and CDUS sensitivity (100% vs 66%), specificity (95% vs 60%), and overall diagnostic accuracy (97% vs 62.8%), assessed by cross tabulations and compared by using the McNemar's two-sided test, were significant (p<0.05). Multidetector CTA is a sensitive technique for the diagnosis of VAD. Used as a complement to unenhanced brain CT, it has the advantage of being readily available and easy to perform.