Chronic kidney disease and its association with cerebral small vessel disease in the general older hypertensive population.

BACKGROUND: Cerebral small vessel disease can be identified using magnetic resonance imaging, and includes white matter hyperintensities, lacunar infarcts, cerebral microbleeds, and brain atrophy. Cerebral small vessel disease and chronic kidney disease share many risk factors, including hypertension. This study aims to explore an association between chronic kidney disease and cerebral small vessel disease, and also to explore the role of hypertension in this relationship. METHODS: With a cross sectional study design, data from 390 older adults was retrieved from the general population study Good Aging in Skåne. Chronic kidney disease was defined as glomerular filtration rate < 60 ml/min/1,73m2. Associations between chronic kidney disease and magnetic resonance imaging markers of cerebral small vessel disease were explored using logistic regression models adjusted for age and sex. In a secondary analysis, the same calculations were performed with the study sample stratified based on hypertension status. RESULTS: In the whole group, adjusted for age and sex, chronic kidney disease was not associated with any markers of cerebral small vessel disease. After stratification by hypertension status and adjusted for age and sex, we observed that chronic kidney disease was associated with cerebral microbleeds (OR 1.93, CI 1.04-3.59, p-value 0.037), as well as with cortical atrophy (OR 2.45, CI 1.34-4.48, p-value 0.004) only in the hypertensive group. In the non-hypertensive group, no associations were observed. CONCLUSIONS: In this exploratory cross-sectional study, we observed that chronic kidney disease was associated with markers of cerebral small vessel disease only in the hypertensive subgroup of a general population of older adults. This might indicate that hypertension is an important link between chronic kidney disease and cerebral small vessel disease. Further studies investigating the relationship between CKD, CSVD, and hypertension are warranted.

Associations of carotid artery flow parameters with MRI markers of cerebral small vessel disease and patterns of brain atrophy.

OBJECTIVES: A growing body of evidence links age related brain pathologies to systemic vascular processes. We aimed to study the prevalence and interrelations between magnetic resonance imaging (MRI) markers of cerebral small vessel disease and patterns of brain atrophy, and their association to carotid duplex ultrasound flow parameters. MATERIALS AND METHODS: We investigated a population based randomised cohort of older adults (n=391) aged 70-87, part of the Swedish Good Aging in Skåne Study. Peak systolic and end diastolic velocities of the carotid arteries were measured by ultrasound, and resistivity- and pulsatility indexes were calculated. Subjects with increased peak systolic velocity indicating carotid stenosis were excluded from analysis. Nine MRI findings were rated by visual scales: white matter changes, pontine white matter changes, microbleeds, lacunar infarctions, medial temporal lobe atrophy, global cortical atrophy, parietal atrophy, precuneus atrophy and central atrophy. RESULTS: MRI pathologies were found in 80% of subjects. Mean end diastolic velocity in common carotid arteries was inversely associated with white matter hyperintensities (OR=0.92; p=0.004), parietal lobe atrophy (OR=0.94; p=0.039), global cortical atrophy (OR=0.90; p=0.013), precuneus atrophy (OR=0.94; p=0.022), "number of CSV pathologies" (ß=-0.07; p<0.001) and "MRI-burden score" (ß=-0.11; p<0.001), after adjustment for age and sex. The latter three were also associated with pulsatility and resistivity indexes. CONCLUSIONS: Low carotid end diastolic velocity, as well as increased carotid resistivity and pulsatility, were associated with signs of cerebral small vessel disease and patterns of brain atrophy, indicating a vascular component in the process of brain aging.

Simulated Dose Reduction for Abdominal CT With Filtered Back Projection Technique: Effect on Liver Lesion Detection and Characterization.

OBJECTIVE: Previous studies have shown the possibility to reduce radiation dose in abdominal CT by 25-50% without negatively affecting detection of liver lesions. How radiation dose reduction affects characterization of liver metastases is not as well known. The objective of this study was to investigate how different levels of simulated dose reduction affect the detection and characterization of liver lesions, primarily hypovascular metastases. A secondary objective was to analyze the relationship between the lesion size and contrast-to-noise ratio (CNR) and the detection rate. MATERIALS AND METHODS: Thirty-nine patients (19 with metastases and 20 without) were retrospectively selected. The following radiation dose levels (DLs) were simulated: 100% (reference level), 75%, 50%, and 25%. Five readers were asked to mark liver lesions and rate the probability of malignancy on a 5-grade Likert scale. Noninferiority analysis using the jackknife free-response ROC (JAFROC) method was performed as well as direct comparison of detection rates and grades. RESULTS: JAFROC analysis showed noninferior detection and characterization of metastases at DL75 as compared with DL100. However, the number of benign lesions and false-positive localizations rated as "suspected malignancy" was significantly higher at DL75. CONCLUSION: Radiation dose can be reduced by 25% without negatively affecting diagnosis of hypovascular liver metastases. Characterization of benign lesions, however, is impaired at DL75, which may lead to unnecessary follow-up examinations. Finally, increased image noise seems to affect the detection of small lesions to a degree that cannot be explained solely by the reduction in CNR.

Evaluation of reproducibility in MRI quantitative volumetric assessment and its role in the prediction of overall survival and progression-free survival in glioblastoma.

BACKGROUND: Residual tumor volume (RTV) and extent of resection (EOR) have previously been shown to affect survival in glioblastoma (GB) patients. Quantitative radiological assessment (QRA) of these factors could potentially affect clinical decision-making in the postoperative period. PURPOSE: The first aim was to evaluate the reproducibility of different volume estimation methods of RTV and EOR by comparing QRA with subjective visual estimation and with objective volume estimations. The second aim was to clarify whether QRA of RTV and EOR would provide accuracy in predicting progression-free survival (PFS) and overall survival (OS) in GB patients. MATERIAL AND METHODS: Seventy GB patients were studied retrospectively. Reproducibility of QRA was compared to conventional visual analysis. Intra-rater agreement between two repeated measurements of 25 patients was calculated. QRA for RTV and EOR was made for the entire study population. Survival analysis was performed by multivariate cox-regression analysis. RESULTS: QRA of RTV and EOR gave superior intra-rater agreement compared to subjective evaluation. Multivariate survival analysis showed prognostic significance on 18 months PFS (hazard ratio [HR] = 0.44, P = 0.003) and OS (HR = 0.42, P = 0.012) at RTV < 1.6 mL and with EOR > 96% on PFS (HR = 2.152, P = 0.005) but not on OS (HR = 1.92, P = 0.053). CONCLUSION: QRA of tumor volumes is more robust compared to standard evaluation methods. Since EOR and RTV are correlated to the prognosis in GB, quantitative analysis of tumor volumes could aid decision-making and patient management postoperatively.

Three-dimensional pelvic incidence is much higher in (thoraco)lumbar scoliosis than in controls.

PURPOSE: The pelvic incidence (PI) is used to describe the sagittal spino-pelvic alignment. In previous studies, radiographs were used, leading to less accuracy in establishing the three-dimensional (3D) spino-pelvic parameters. The purpose of this study is to analyze the differences in the 3D sagittal spino-pelvic alignment in adolescent idiopathic scoliosis (AIS) subjects and non-scoliotic controls. METHODS: Thirty-seven female AIS patients that underwent preoperative supine low-dose computed tomography imaging of the spine, hips and pelvis as part of their general workup were included and compared to 44 non-scoliotic age-matched female controls. A previously validated computerized method was used to measure the PI in 3D, as the angle between the line orthogonal to the inclination of the sacral endplate and the line connecting the center of the sacral endplate with the hip axis. RESULTS: The PI was on average 46.8° ± 12.4° in AIS patients and 41.3° ± 11.4° in controls (p = 0.025), with a higher PI in Lenke type 5 curves (50.6° ± 16.2°) as compared to controls (p = 0.042), whereas the Lenke type 1 curves (45.9° ± 12.2°) did not differ from controls (p = 0.141). CONCLUSION: Lenke type 5 curves show a significantly higher PI than controls, whereas the Lenke type 1 curves did not differ from controls. This suggests a role of pelvic morphology and spino-pelvic alignment in the pathogenesis of idiopathic scoliosis. Further longitudinal studies should explore the exact role of the PI in the initiation and progression of different AIS types. These slides can be retrieved under Electronic Supplementary Material.

Tumor Necrosis Factor Receptor 1 and 2 Are Associated With Risk of Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Raised plasma concentrations of tumor necrosis factor receptors (TNFR) have been linked to arterial stiffness, cerebral microbleeds, and vascular events. The aim of this study was to investigate the association of circulating levels of TNFR1 and TNFR2 with risk for future intracerebral hemorrhage (ICH). METHODS: The population-based MDCS cohort (Malmö Diet and Cancer Study; n=28 449) was conducted in 1991 to 1996. A nested case-control study was performed in the MDCS, including 220 cases who experienced ICH during the follow-up period (mean age at inclusion 62 years, 48% men) and 244 matched controls. Of the 220 ICH cases, 68 died within 28 days. Conditional logistic regression was used to study the association between plasma levels of TNFR1 and TNFR2 and incident ICH, adjusting for known ICH risk factors. RESULTS: Concentrations of both TNFR1 and TNFR2 were significantly higher in subjects who developed ICH during the follow-up. The associations remained after adjustment for ICH risk factors (TNFR1: odds ratio [OR], 2.28; 95% confidence interval [CI], 1.26-4.11; P=0.006; TNFR2: OR, 1.77; CI, 1.16-2.70; P=0.008). ORs were somewhat higher for nonlobar ICH (3.04; CI, 1.29-7.14 and 2.39; CI, 1.32-4.32, respectively) than for lobar ICH (2.03; CI, 0.93-4.41 and 1.35; CI, 0.78-2.37, respectively). TNFR1 and TNFR2 were also associated with increased risk of fatal ICH (TNFR1: OR, 4.42; CI, 1.67-11.6; TNFR2: OR, 2.90; CI, 1.50-5.58) and with poor functional outcome according to the modified Rankin Scale. CONCLUSIONS: High plasma levels of TNFR1 and TNFR2 were associated with incident ICH, most clearly with ICH of nonlobar location. The results suggest that tumor necrosis factor-mediated inflammation could be associated with vascular changes preceding ICH.

Measurement of vascular water transport in human subjects using time-resolved pulsed arterial spin labelling.

Most approaches to arterial spin labelling (ASL) data analysis aim to provide a quantitative measure of the cerebral blood flow (CBF). This study, however, focuses on the measurement of the transfer time of blood water through the capillaries to the parenchyma (referred to as the capillary transfer time, CTT) as an alternative parameter to characterise the haemodynamics of the system. The method employed is based on a non-compartmental model, and no measurements need to be added to a common time-resolved ASL experiment. Brownian motion of labelled spins in a potential was described by a one-dimensional general Langevin equation as the starting point, and as a Fokker-Planck differential equation for the averaged distribution of labelled spins at the end point, which takes into account the effects of flow and dispersion of labelled water by the pseudorandom nature of the microvasculature and the transcapillary permeability. Multi-inversion time (multi-TI) ASL data were acquired in 14 healthy subjects on two occasions in a test-retest design, using a pulsed ASL sequence and three-dimensional gradient and spin echo (3D-GRASE) readout. Based on an error analysis to predict the size of a region of interest (ROI) required to obtain reasonably precise parameter estimates, data were analysed in two relatively large ROIs, i.e. the occipital lobe (OC) and the insular cortex (IC). The average values of CTT in OC were 260 ± 60 ms in the first experiment and 270 ± 60 ms in the second experiment. The corresponding IC values were 460 ± 130 ms and 420 ± 139 ms, respectively. Information related to the water transfer time may be important for diagnostics and follow-up of cerebral conditions or diseases characterised by a disrupted blood-brain barrier or disturbed capillary blood flow.

CT angiography in non-traumatic subarachnoid hemorrhage: the importance of arterial attenuation for the detection of intracranial aneurysms.

BACKGROUND: Computed tomography angiography (CTA) is today the primary method for the detection of intracranial aneurysms. The technique has evolved considerably during the last decade, and it is important to establish criteria for high image quality, especially with regard to improving the diagnosis of small aneurysms. PURPOSE: To evaluate diagnostic accuracy and image quality by arterial attenuation of CTA in patients with non-traumatic subarachnoid hemorrhage (SAH). MATERIAL AND METHODS: Between 2005 and 2011, CTA and digital subtraction angiography (DSA) were performed in 326 patients with non-traumatic SAH. Sensitivity and specificity for aneurysm detection were evaluated per patient, per aneurysm, and per ruptured aneurysm. The image quality of CTA was evaluated by arterial attenuation measurements (mean Hounsfield units [HU]) in the internal carotid artery (ICA). RESULTS: In all, 285 aneurysms in 235 patients were detected by DSA, 19 aneurysms were missed on CTA, and 223 aneurysms were classified as ruptured. In 91 patients, no aneurysm was found. Correct diagnosis with CTA was made in 28 patients with perimesencephalic hemorrhage. Sensitivity and specificity (95% confidence interval) calculated per patient were 91.6% (87.3-94.9) and 87.9% (79.8-93.6), respectively, per aneurysm 93.3% (89.7-95.9) and 88% (79.9-93.6), and per ruptured aneurysm 94.9% (91.3-97.3) and 96.7% (90.7-99.3). Arterial attenuation (in HU) in CTA revealing true positive ruptured aneurysms and true negative aneurysms (mean 535 ± 110 HU) differed significantly (P = 0.02) from false negative ruptured aneurysms (mean 424 ± 30 HU). CONCLUSION: CTA has high sensitivity and specificity for the detection of ruptured aneurysms. The sensitivity is related to arterial attenuation in the ICA.

Incidence of cerebral small vessel disease-related MR markers in the Swedish general population 'Good Aging in Skåne'(GÅS) study.

BACKGROUND AND OBJECTIVES: Cerebral small vessel disease (CSVD) is associated to cognitive decline and dementia. Neuroimaging changes of CSVD are highly prevalent above 80 years. Only few studies report on incidence of CSVD in high age. We have investigated the incidence and prevalence of magnetic resonance imaging (MRI) markers of CSVD and risk factors in the general older population. METHODS: As part of the general population Good Aging in Skåne cohort study (GÅS), 241 persons (mean age 76.3 years) underwent two brain MRI, 3-T scanner with a mean interval of 5.9 years. The incidence of white matter hyperintensities (WMH), lacunar infarction, cerebral atrophies and cerebral microbleeds (CMB) were calculated and the relationship to risk factors analysed by a multivariate regression analysis. Medial temporal lobe atrophy (MTA) was graded according to Scheltens'18 scale and CMB were defined as having > 1 small (0.2-0.5 cm) hypointense lesion. RESULTS: The 6-year incidence of CMB, WMH and MTA were, 19%, 17% and 13% respectively, corresponding to 170/1,000 py., 172/1,000 py., and respectively 167/1,000 py. The incidence of CSVD according to the modified STRIVE score was 33%, 169/1,000 py and the prevalence at baseline was 73%. Moderate to high intake of alcohol was related to increased incidence of MTA and higher STRIVE score. Exposure to smoking was related to higher incidence of CMB and higher STRIVE score, adjusted for other known risk factors. CONCLUSION: CSVD is highly prevalent in the general older population and the 6-year incidence of WMH, CMB and MTA ranges from 13 to 19 percent. The modifiable lifestyle factors: smoking, and moderate alcohol intake are related to incident CSVD.

A Novel Radiographic Pattern Related to Poor Prognosis in Patients with Prostate Cancer with Metastatic Spinal Cord Compression.

Background: Prostate cancer spinal bone metastases can have a radiographic profile that mimics multiple myeloma. Objective: To analyse the presence and prognostic value of myeloma-like prostate cancer bone metastases and its relation to known clinical, molecular, and morphological prognostic markers. Design setting and participants: A cohort of 110 patients with prostate cancer who underwent surgery for metastatic spinal cord compression (MSCC) was analysed. Spinal bone metastases were classified as myeloma like (n = 20) or non-myeloma like (n = 90) based on magnetic resonance imaging prior to surgery. An immunohistochemical analysis of metastasis samples was performed to assess tumour cell proliferation (percentage of Ki67-positive cells) and the expression levels of prostate-specific antigen (PSA) and androgen receptor (AR). The metastasis subtypes MetA, MetB, and MetC were determined from transcriptomic profiling. Outcome measurements and statistical analysis: Survival curves were compared with the log-rank test. Univariate and multivariate Cox proportional hazard models were used to assess the effects of prognostic variables. Groups were compared using the Mann-Whitney U test for continuous variables and the chi-square test for categorical variables. Results and limitations: Patients with the myeloma-like metastatic pattern had median survival after surgery for MSCC of 1.7 (range 0.1-33) mo, while the median survival period of those with the non-myeloma-like pattern was 13 (range 0-140) mo (p < 0.001). The myeloma-like appearance had an independent prognostic value for the risk of death after MSCC surgery (adjusted hazard ratio 2.4, p = 0.012). Postoperative neurological function was significantly reduced in the myeloma-like group. No association was found between the myeloma-like pattern and morphological markers of known relevance for this patient group: the transcriptomic subtypes MetA, MetB, and MetC; tumour cell proliferation; and AR and PSA expression. Conclusions: A myeloma-like metastatic pattern identifies an important subtype of metastatic prostate cancer associated with poor survival and neurological outcomes after surgery for MSCC. Patient summary: This study describes a novel radiographic pattern of prostate cancer bone metastases and its relation to poor patient prognosis.

Vertebral Hemangiomas: Prevalence, new classification and natural history. magnetic resonance imaging-based retrospective longitudinal study.

BACKGROUND AND PURPOSE: To determine the prevalence of vertebral hemangiomas (VHs), establish a new classification of VHs based on their MRI-signal pattern, and study their natural history. METHODS: MRI of 1000 consecutive patients who underwent at least two MRI with an interval of at least 3 years. Growth rate and change of MRI-signal pattern during the follow-up period were the parameters included in studying the natural history of VHs. RESULTS: The prevalence of VHs was 41%. VHs were classified as type I-IV with fat-rich VHs (type I), constituted 79% of all VHs. VHs were more common among females 43% versus males 39%, p = .22. The most affected vertebra was L1. Occurrence rates for cervical (1%), thoracic (7%), and lumbar spine (10%) differed significantly (p < .001). The prevalence of VHs increased with age regardless of gender or spinal part involved (p < .001). Only 26% of VHs changed their size and 4% changed their signal during the average follow-up of 7 years. All VHs were slowly growing lesions (average expected growth of <3 mm/10 years). No significant difference between growth rate of VHs type I (0.25 mm/year) and other types of VHs. None of the VHs that were initially reported as "metastases cannot be rule out" showed alarming change in signal or size. CONCLUSIONS: VH can be classified into four types based on their MRI-signal pattern. Regardless of their type, VHs are slowly growing lesions. The presence of typical morphological pattern should enable radiologists to confidently differentiate them from vertebral metastases.

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

BACKGROUND: Swirl 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. METHODS: CTs 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. RESULTS: Inter- 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). CONCLUSIONS: As swirl sign showed to be an ominous sign, we recommend identification of this sign in cases of ICHs.

Intracranial manifestations in SAPHO syndrome: the first case report in literature.

A 41-year-old woman with SAPHO syndrome presented with numbness of her left arm followed by a generalized seizure. Computed tomography and magnetic resonance imaging of the brain revealed a small ring enhancing lesion in the right parietal lobe with adjacent meningeal thickening and enhancement. Surgical removal and histopathology showed evidence of severe chronic sterile inflammation and no malignant cell. Symptoms recurred and a lesion were again detected on radiological follow-up, but improvement occurred following treatment with antibiotics and biphosphonate, achieving a low inflammatory activity, reduction in CNS lesions and relative clinical well-being. This is a first report in literature about the central nervous system involvement in a patient with SAPHO syndrome.

Patients with adolescent idiopathic scoliosis of Lenke type-1 curve exhibit specific pedicle width pattern.

INTRODUCTION: Study aim was to find out if patients with Lenke type 1 curve exhibit smaller pedicles and specific pedicle width pattern compared with individuals with no scoliosis. MATERIALS AND METHODS: 4,828 pedicle width measurements (T1-L5) in 61 consecutive patients with adolescent idiopathic scoliosis of Lenke type 1 curve, 61 control subjects, and 20 patients with Lenke type 5 curve, were retrospectively performed by an experienced neuroradiologist. RESULTS: Among patients with Lenke type 1 curve, the differences between the width of right and left upper thoracic pedicles were statistically significant; smallest at right T4 (2.6 mm). At scoliotic apex, the pedicles on the concave (left) side were significantly smaller than those on the convex (right) side; smallest at left T7 (3.2 mm). Among patients with Lenke type 1 curve, 97% had pedicle width <4 mm. CONCLUSIONS: Our study showed that patients with Lenke type 1 curve exhibit smaller pedicles and asymmetric pedicle width compared with control subjects.

Spinal epidural lipomatosis: a common imaging feature in Scheuermann disease.

STUDY DESIGN: Retrospective study. OBJECTIVES: To find out if spinal epidural lipomatosis (SEL) occurs more commonly among patients with Scheuermann disease than in the general population. SUMMARY AND BACKGROUND: On the basis of our own radiologic and operative observation, SEL seems to occur frequently in patients with Scheuermann disease. METHODS: Magnetic resonance imaging of 87 individuals (72% male, average age 19±6 y) from 2 centers (29 consecutive patients with Scheuermann disease and 58 controls) were retrospectively evaluated by 2 neuroradiologists. Spinal epidural fat (EF) at seventh thoracic vertebra (EF7), maximum EF (EFmax), dural sac diameter at T7 and at the level of maximum EF (DS7 and DSmax) were measured. EF ratios at T7 (EFR7) and at maximum EF (EFRmax) were calculated as EF/DS. Body mass index (BMI) for study population and kyphosis severity for the patients were recorded. Mann-Whitney, Spearman correlation, and χ tests were performed dependent on the variable in question. RESULTS: EF7, DS7, EFmax, EFR7, and EFRmax was significantly higher among patients with Scheuermann disease (EFmax 5.7±2.4 mm) than among controls (EFmax 3.8±1.1 mm), P<0.001. Twelve patients with Scheuermann disease (41%) fulfilled our proposed criteria for the diagnosis of SEL (EFmax>6 mm+EFRmax>0.51) compared with 2 (3%) among controls (P<0.001). Patients with Scheuermann disease exhibited higher BMI than controls (24.9±5 kg/m vs. 22.9±4 kg/m, P=0.138). Logistic regression showed that the occurrence of SEL among patients with Scheuermann disease was independent of BMI (P=0.880). The degree of kyphosis in patients with Scheuermann's disease (62±20°) was correlated to the amount of the EF. CONCLUSIONS: As SEL occurs more frequently among patients with Scheuermann disease, spine magnetic resonance imaging should be routinely performed to screen each of these patients to avoid impending neurological injury during surgery, especially in those exhibiting SEL.

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 (κ 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.

Patients having surgery for ulnar nerve compression at the elbow rarely have affection of the spinal nerve root at C8-Th1 levels.

Cervical pathology may contribute to residual problems after surgery for ulnar nerve compression. We aimed to evaluate the presence of pathological conditions in spinal cord and cervical spinal nerve roots in patients surgically treated for ulnar nerve compression at elbow. In a cohort of patients, surgically treated for ulnar nerve compression at elbow, magnetic resonance images (MRI; performed 3 years pre/postoperatively) were evaluated by a neuroradiologist blinded to patient characteristics and outcome of surgery. Cervical conditions were assessed and related to patient characteristics, preoperative McGowan grade, and outcome. Among 62 patients (45 unilaterally and 17 bilaterally), only one had spinal nerve root affection of nerve roots contributing to the ulnar nerve (C8-Th1). About half of the patients, mainly those at higher age, had alterations affecting C3-C7 spinal nerve roots at both surgically treated and contralateral, non-surgically treated, sides. Only few other changes were observed at cervical levels. A high McGowan grading was related to a high frequency of spinal nerve root affection. Smokers were more frequently observed among those with spinal nerve root affection at C3-C7 levels at surgically treated side. Residual problems, expressed as patient dissatisfaction and DASH score ≥40, were common. Spinal nerve roots, contributing to the ulnar nerve, are rarely affected in surgically treated patients with ulnar nerve compression at elbow even though pathology is often observed at other cervical levels. Pathology is often detected at other cervical spinal nerve root levels at surgically treated and contralateral sides, particularly among older patients, smokers, and in conjunction with worse preoperative McGowan grade. No relation between cervical pathology and outcome of ulnar nerve surgery is seen.

A pilot study of methods for prediction of poor outcome by head computed tomography after cardiac arrest.

INTRODUCTION: In Sweden, head computed tomography (CT) is commonly used for prediction of neurological outcome after cardiac arrest, as recommended by guidelines. We compare the prognostic ability and interrater variability of routine and novel CT methods for prediction of poor outcome. METHODS: Retrospective study including patients from Swedish sites within the Target Temperature Management after out-of-hospital cardiac arrest trial examined with CT. Original images were assessed by two independent radiologists blinded from clinical data with eye-balling without pre-specified criteria, and with a semi-quantitative assessment. Grey-white-matter ratios (GWR) were quantified using models with 4-20 manually placed regions of interest. Prognostic abilities and interrater variability were calculated for prediction of poor outcome (modified Rankin Scale 4-6 at 6 months) for early (<24 h) and late (≥24 h) examinations. RESULTS: 68/106 (64 %) of included patients were examined < 24 h post-arrest. Eye-balling predicted poor outcome with 89-100 % specificity and 15-78 % sensitivity. GWR < 24 h predicted neurological outcome with unsatisfactory to satisfactory Area Under the Receiver Operating Characteristics Curve (AUROC: 0.54-0.64). GWR ≥ 24 h yielded very good to excellent AUROC (0.80-0.93). Sensitivities increased > 2-3-fold in examinations performed after 24 h compared to early examinations. Combining eye-balling with GWR < 1.15 predicted poor outcome without false positives with sensitivities remaining acceptable. CONCLUSION: In our cohort, qualitative and quantitative CT methods predicted poor outcome with high specificity and low to moderate sensitivity. Sensitivity increased relevantly after the first 24 h after CA. Interrater variability poses a problem and indicates the need to standardise brain CT evaluation to increase the methods' safety.

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

BACKGROUND: We 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. METHODS: Dimensions of 120 maxillary and frontal sinuses from head CTs were measured independently by two radiologists. RESULTS: The 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. CONCLUSION: We 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.

Reduction of flow velocities in patients with ischemic events in the middle cerebral artery--long-term follow-up with ultrasound.

Data concerning the persistent reduction of flow velocities measured by transcranial color-coded sonography (TCCS) in relation to the clinical and radiological outcome among patients with ischemic events in middle cerebral artery (MCA) territory is scarce. Patients with > or = 50% reduction of peak systolic velocities (PSV-MCA) as compared to the contralateral MCA were prospectively included in follow-up by TCCS (mean 404 days). Out of 849 patients with stroke admitted to our stroke unit, 25 patients showed reduced PSV-MCA and included in the analyses of this study. Ten (40%) survivors showed persistent reduction of PSV-MCA. None of the patients with normalized PSV-MCA suffered an ischemic event compared with three patients with persistent reduction of PSV-MCA (all had ipsilateral occlusion of the internal carotid artery caused by dissection). Patients with persistently reduced PSV-MCA exhibited significantly (Mann-Whitney test, p = 0.02) larger infarct volumes on CT (mean +/- SD 38 +/-50 cm3) compared to those with normalized PSV-MCA (6 +/- 7 cm3). The functional outcome were, however, similar in patients with normalized and those with persistently reduced PSV-MCA. We found that a relatively high percentage (40%) of patients suffered ischemic event in the MCA territory with initial reduction of flow velocity on TCCS showed persistent reduction on long term follow-up.