Kasim Abul-Kasim

Intradural spinal tumors: current classification and MRI features

The differential diagnosis of intradural spinal tumors is primarily based on location, but the clinical presentation, age, and gender of the patient are also important factors in determining the diagnosis. This comprehensive review focuses on the current classification, clinical symptoms, and MRI features of the more common intradural extramedullary and intramedullary neoplastic lesions. This review does not include extradural lesions.

The Neuroanatomic Localization of Epstein-Barr Virus Encephalitis May Be a Predictive Factor for Its Clinical Outcome: A Case Report and Review of 100 Cases in 28 Reports.

Encephalitis is one of the manifestations of infection with Epstein-Barr virus with clinical outcome varying from complete recovery to death. A 16-year-old boy with Epstein-Barr virus encephalitis with global cortical and subcortical gray matter involvement and a full clinical recovery is reported. The case inspired a literature review which yielded 100 cases of Epstein-Barr virus encephalitis subjected to radiological investigation and published in 28 reports. Cerebellum and basal ganglia were reported to be equally involved by Epstein-Barr virus infection, next to cerebral hemisphere. Patients with isolated hemispheric gray or white matter involvement were reported to achieve good recovery while almost half of the patients with thalamic involvement developed sequelae. The highest mortality rate was among patients with isolated brain stem involvement. In conclusion, neuroanatomic distribution of the radiological abnormalities in Epstein-Barr virus encephalitis may be useful as a prognostic marker.

Computed tomography measurements of different dimensions of maxillary and frontal sinuses.

BackgroundWe have previously proposed the use of Doppler ultrasound to non-invasively stage sinus infection, as we showed that acoustic streaming could be generated in nonpurulent sinus secretions and helped to distinguish it from mucopurulent sinus secretions. In order to continue this development of a clinically applicable Doppler equipment, we need to determine different dimensions of the paranasal sinuses, especially the thickness of the anterior wall of the maxillary sinus (at the canine fossa). To the best of our knowledge, this is the first report on the thickness of the canine fossa. This study aimed to (a) estimate different dimensions of the maxillary and frontal sinuses measured on computed tomography (CT) of the head, (b) define cut-off values for the normal upper and lower limits of the different measured structures, (c) determine differences in age, side and gender, (d) compare manually and automatically estimated maxillary sinuses volumes, and (e) present incidental findings in the paranasal sinuses among the study patients.MethodsDimensions of 120 maxillary and frontal sinuses from head CTs were measured independently by two radiologists.ResultsThe mean value of the maxillary sinus volume was 15.7 ± 5.3 cm3 and significantly larger in males than in females (P = 0.004). There was no statistically significant correlation between the volume of maxillary sinuses with age or side. The mean value of the bone thickness at the canine fossa was 1.1 ± 0.4 mm. The automatically estimated volume of the maxillary sinuses was 14-17% higher than the calculated volume. There was high interobserver agreement with regard to the different measurements performed in this study. Different types of incidental findings of the paranasal sinuses were found in 35% of the patients.ConclusionWe presented different dimensions of the maxillary and frontal sinuses on CTs. We believe that our data are necessary for further development of a clinically applicable Doppler equipment for staging rhinosinusitis.

Reliability of Low-Radiation Dose CT in the Assessment of Screw Placement After Posterior Scoliosis Surgery, Evaluated With a New Grading System

Study Design. A retrospective study. Objective. To evaluate the reliability of computed tomography (CT) with low radiation dose in the assessment of implant status in patients with adolescent idiopathic scoliosis (AIS). Summary of Background Data. The use of all-pedicle screw construct in scoliosis corrective surgery continues to gain increasing popularity since their introduction 1994 although their use in the thoracic spine carries a potential risk for neurovascular complications. CT is the method widely used to evaluate screw placement. Methods. Retrospective analysis of 46 consecutive low-dose spine CT in patients with AIS after posterior corrective surgery. Status of 809 titanium screws (642 thoracic) was evaluated. The degree of interobserver and intraobserver agreements about implant status was used as an indicator of the reliability of the low-dose spine CT in the assessment of accuracy of pedicle screw insertion. A new grading system has been developed for this purpose. Five types of misplacement have been evaluated: lateral, medial, and anterior cortical perforations; endplate perforation; and foraminal perforation. Results. The analysis has shown a substantial interobserver and intraobserver agreements (&kgr;: 0.69 and 0.76, respectively) in differentiating pedicle screws with acceptable placement from screws with partial or total cortical perforation. None of the examinations was subjectively classified as unreliable. Conclusion. The study has shown that low-dose spine CT is a reliable method in evaluating screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the here proposed grading system. The new grading system of screw misplacement was feasible and in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. The reliability of low-dose spine CT in evaluation of lateral and medial cortical perforations was substantial. To reduce the radiation load, the postoperative assessment of titanium implants should be performed with low-dose CT.

Optimization of Radiation Exposure and Image Quality of the Cone-beam O-arm Intraoperative Imaging System in Spinal Surgery.

Study Design Retrospective study. Objectives To optimize the radiation doses and image quality for the cone-beam O-arm surgical imaging system in spinal surgery. Summary of Background Neurovascular compromise has been reported after screw misplacement during thoracic pedicle screw insertion. The use of O-arm with or without navigation system during spinal surgery has been shown to lower the rate of screw misplacement. The main drawback of such imaging surgical systems is the high radiation exposure. Methods Chest phantom and cadaveric pig spine were examined on the O-arm with different scan settings: 2 were recommended by the O-arm manufacturer (120 kV/320 mAs, and 120 kV/128 mAs), and 3 low-dose settings (80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs). The radiation doses were estimated by Monte Carlo calculations. Objective evaluation of image quality included interobserver agreement in the measurement of pedicular width in chest phantom and assessment of screw placement in cadaveric pig spine. Results The effective dose/cm for 120 kV/320 mAs scan was 13, 26, and 69 times higher than those delivered with 80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs scans, respectively. Images with 60 kV/40 mAs were unreliable. Images with 80 kV/80 mAs were considered reliable with good interobserver agreement when measuring the pedicular width (random error 0.38 mm and intraclass correlation coefficient 0.979) and almost perfect agreement when evaluating the screw placement (&kgr; value 0.86). Conclusions The radiation doses of the O-arm system can be reduced 5 to 13 times without negative impact on image quality with regard to information required for spinal surgery.

Swirl sign in intracerebral haemorrhage: definition, prevalence, reliability and prognostic value

BackgroundSwirl sign has previously been described in epidural hematomas as areas of low attenuation, radiolucency or irregular density. The aims of this study were to describe swirl sign in ICH, study its prevalence, study the reliability of the subjective evaluation on computed tomography (CT), and to explore its prognostic value.MethodsCTs of 203 patients with ICH were retrospectively evaluated for the presence of swirl sign. Association between swirl sign and different clinical and radiological variables was studied.ResultsInter- and intraobserver agreement with regard to the occurrence of swirl sign was substantial (К 0.80) and almost perfect (К 0.87), respectively. Swirl sign was found in 30% of the study population. 61% of patients with swirl sign were dead at one month compared with 21% of those with no swirl sign (p < 0.001). Only 19% of patients with swirl sign exhibited favorable outcome at three months compared with 53% of those with no swirl sign (p < 0.001). Patients with swirl sign exhibited larger ICHs with average ICH-volume 52 ± 50 ml (median 42 ml) compared with 15 ± 25 ml (median 6) in patients whose CT did not show swirl sign (p < 0.001). Swirl sign was independent predictor of death at one month (p = 0.03; adjusted odds ratio 2.6, 95% CI 1.1 – 6), and functional outcome at three months (p = 0.045; adjusted odds ratio 2.6, 95% CI 1.02 – 6.5).ConclusionsAs swirl sign showed to be an ominous sign, we recommend identification of this sign in cases of ICHs.

Low-dose computed tomography of the paranasal sinuses: radiation doses and reliability analysis

PURPOSE The study aimed to (1) optimize the radiation doses of computed tomography (CT) of paranasal sinuses, (2) compare the radiation doses of different CT protocols with that of plain radiography, and (3) evaluate the reliability of low-dose CT in the detection of pathology and characterization of the detected pathology. MATERIALS AND METHODS A head phantom was examined with different scan parameters to define a cutoff value to which the radiation dose can be reduced without negative impact on image quality. Kruskal-Wallis test and Wilcoxon W test were performed to compare the effective doses of the plain radiography in 30 patients with that of 3 different CT protocols in a total of 90 patients. The interobserver and intraobserver agreement in the detection of pathologic findings and in characterization of the pathology was estimated by calculating κ value. RESULTS The effective doses of plain radiography and low-dose CT were 0.098 and 0.045 mSv, respectively (P < .001). The effective dose of standard CT of sinuses (0.371 mSv) was 3.8 times higher than that of plain radiography and 8.2 times higher than that of low-dose CT (P < .001). The interobserver and intraobserver agreement on CT with regard to detection of pathology and pathology characterization was almost perfect (κ values 0.81-1) compared to fair (κ values 0.38-0.39) in plain radiography. CONCLUSIONS The here proposed low-dose CT means significant dose reduction and is a reliable method in the investigation of the paranasal sinuses.

Hyperdense middle cerebral artery sign is an ominous prognostic marker despite optimal workflow.

Abul‐Kasim K, Brizzi M, Petersson J. Hyperdense middle cerebral artery sign is an ominous prognostic marker despite optimal workflow.
Acta Neurol Scand: DOI: 2010: 122: 132–139.
© 2009 The Authors Journal compilation

Early do-not-resuscitate orders in intracerebral haemorrhage; frequency and predictive value for death and functional outcome. A retrospective cohort study

IntroductionIn former studies from North America early Do-Not–Resuscitate orders (DNR orders) in patients with intracerebral haemorrhage (ICH) had negative prognostic impact on mortality. The influence of DNR orders on functional outcome and whether DNR orders are grounded on relevant patient characteristics is unknown. We aimed to determine the frequency and predictive factors of DNR-orders and its association to prognosis, in ICH patients, in Scandinavia.MethodsIn 197 consecutive ICH patients admitted to Skåne University Hospital, Malmö, Sweden, between January 2007 and June 2009, information of the presence of DNR orders within 48 hours, clinical and radiological characteristics was retrieved by review of patient medical journal and computed tomography scans. Determinants of DNR-orders, one-month case fatality and bad functional outcome (modified Rankin Scale, grade 4–6) were assessed by logistic regression analysis.ResultsDNR orders were made in 41% of the cases. After adjustment for confounding factors, age ≥ 75 years (Odds Ratio (95% confidence interval) 4.2(1.8-9.6)), former stroke (5.1(1.9-3.1)), Reaction Level Scale grade 2–3 and 4 (7.0(2.8-17.5) and (4.1(1.2-13.5), respectively) and intraventricular haemorrhage (3.8(1.6-9.4)) were independent determinants of early DNR orders. Independent predictors of one-month case fatality was age ≥ 75 years (3.7(1.4-9.6)) volume ≥ 30 ml (3.5(1.3-9.6)) and DNR orders (3.5(1.5-8.6)). Seizure (6.0(1.04-34.2) and brain stem hemorrhage (8.0(1.1-58.4)) were related to bad functional outcome, whereas early DNR order was not (3.5(0.99-12.7)).ConclusionsWell known prognostic factors are determinants for DNR orders, however DNR orders are independently related to one-month case fatality. In addition to improvements of the local routines, we welcome a change of attitude with an enhanced awareness of the definition of, and a more careful approach with respect to DNR orders.

Increased rod stiffness improves the degree of deformity correction by segmental pedicle screw fixation in adolescent idiopathic scoliosis

BackgroundThere are limited reports in literature studying the impact of rod diameter and stiffness on the degree of deformity correction in patients with AIS.AimsThe aims of this study were to evaluate the 3-dimentional deformity correction achieved by segmental pedicle screw fixation in patients with adolescent idiopathic scoliosis, and to find out if learning or the change to stiffer rods had any positive impact on deformity correction.Study designRetrospective study.MethodsPlain radiographs and low-dose spine CTs of 116 consecutive patients (aged 15.9 ± 2.8 years) operated during the period 2005-2009 (group 1: patients operated autumn 2005-2006; group 2: 2007; group 3: 2008; group 4: 2009) were retrospectively evaluated.ResultsThere was no statistically significant difference between the correction of the Cobb angle (P = 0.425) or lower end vertebra tilt (P = 0.298) in patients operated during the first versus the remaining periods of the study. No restoration of the sagittal kyphosis was reported in the first period compared with 5.9° in the last study period (P < 0.001). The correction of vertebral rotation was also improved from 4.2° to 7.8° (P < 0.001) for the same periods. For the whole study population, there was statistically significant correlation between the order of the operation (patient number) and the restoration of sagittal kyphosis (r = -0.344, P = 0.001), and the correction of vertebral rotation (r = 0.370, P < 0.001), but not for the Cobb angle or LEVT. However, there was no significant difference in restoration of sagittal kyphosis and the vertebral rotation in the first 17 patients compared with the last 17 patients operated with rods of 5.5 mm diameter (P = 0.621, and 0.941, respectively), indicating that rod stiffness had more impact on the deformity correction than did learning.ConclusionsThis study showed that rod stiffness had more impact on the deformity correction than did learning.