Radiography and Computed Tomography Detection of Intimal and Medial Calcifications in Leg Arteries in Comparison to Histology.

Calcifications are common in the tunica intima and tunica media of leg arteries. There is growing interest in medial arterial calcifications, as they may be modifiable with treatment. We aimed to investigate radiography and computed tomography (CT) for the detection and characterization of both types of arterial calcification in leg arteries in relation to histology. In a postmortem study we therefore investigated 24 popliteal and 24 tibial arteries. The reference standard was presence of arterial calcification and the dominance of intimal or medial calcification on histology. Radiographs and CT scans were scored for presence of calcification and for dominant intimal or medial pattern based on prespecified criteria (annularity, thickness, continuity). Both radiography and CT detected 87% of histologically proven calcifications but missed mild calcifications in 13%. When only the arteries with detected calcifications were included, a moderate agreement was observed on intimal/medial location of calcifications between histology and radiography (correct in 19/24 arteries (79%); Kappa 0.58) or CT (correct in 33/46 arterial segments (72%); Kappa 0.48). With both modalities there was a slight tendency to classify intimal calcifications as being located in the media and to miss media calcification. Our study demonstrates the potential and limitations of both radiography and CT to detect and classify arterial calcifications in leg arteries.

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

BACKGROUND AND PURPOSE: Risk 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 METHODS: 1133 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. RESULTS: Mean 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. CONCLUSIONS: In this study with patients suspected of acute ischemic stroke, basal ganglia calcifications were common and significantly associated with older age and lower BMI.

Risk factors for atherosclerotic and medial arterial calcification of the intracranial internal carotid artery.

BACKGROUND AND AIMS: Calcifications of the intracranial internal carotid artery (iICA) are an important risk factor for stroke. The calcifications can occur both in the intimal and medial layer of the vascular wall. The aim of this study is to assess whether medial calcification in the iICA is differently related to risk factors for cardiovascular disease, compared to intimal calcification. METHODS: Unenhanced thin slice computed tomography (CT) scans from 1132 patients from the Dutch acute stroke study cohort were assessed for dominant localization of calcification (medial or intimal) by one of three observers based on established methodology. Associations between known cardiovascular risk factors (age, gender, body mass index, pulse pressure, eGFR, smoking, hypertension, diabetes mellitus, hyperlipidemia, previous vascular disease, and family history) and the dominant localization of calcifications were assessed via logistic regression analysis. RESULTS: In the 1132 patients (57% males, mean age 67.4 years [SD 13.8]), dominant intimal calcification was present in 30.9% and dominant medial calcification in 46.9%. In 10.5%, no calcification was seen. Age, pulse pressure and family history were risk factors for both types of calcification. Multivariably adjusted risk factors for dominant intimal calcification only were smoking (OR 2.09 [CI 1.27-3.44]) and hypertension (OR 2.09 [CI 1.29-3.40]) and for dominant medial calcification diabetes mellitus (OR 2.39 [CI 1.11-5.14]) and previous vascular disease (OR 2.20 [CI 1.30-3.75]). CONCLUSIONS: Risk factors are differently related to the dominant localizations of calcifications, a finding that supports the hypothesis that the intimal and medial calcification represents a distinct etiology.

Hippocampal Calcifications: Risk Factors and Association with Cognitive Function.

Purpose To identify risk factors for hippocampal calcifications and to investigate the association between hippocampal calcifications and cognitive function. Materials and Methods For this retrospective study, consecutive patients visiting a memory clinic at a Dutch general hospital between April 2009 and April 2015 were identified. All individuals underwent a standard diagnostic work-up including cognitive tests and brain CT. The following vascular risk factors were assessed: hypertension, diabetes mellitus, hyperlipidemia, and smoking. Cognitive screening consisted of the Cambridge Cognitive Examination, which includes the Mini-Mental State Examination. CT scans were analyzed for the presence and severity (absent, mild, moderate, severe) of hippocampal calcifications. One measure per patient, only the most severe score, was used. Logistic regression was used to identify risk factors for hippocampal calcifications, and linear regression was used for the association between hippocampal calcifications (patient level) and cognitive function. Results A total of 1991 patients (mean age, 78 years; range, 45-96 years) were included. The mean age of women was 79 years (range, 47-96 years), and the mean age of men was 77 years (range, 45-95 years). Of the 1991 patients, 380 (19.1%) had hippocampal calcifications. Older age (odds ratio [OR] per year, 1.05; 95% confidence interval [CI]: 1.03, 1.06), diabetes mellitus (OR, 1.50; 95% CI: 1.12, 2.00), and smoking (OR, 1.49; 95% CI: 1.05, 2.10) were associated with the presence of hippocampal calcifications. No associations were found between presence and severity of hippocampal calcifications and cognitive function. Conclusion Older age, diabetes mellitus, and smoking were associated with an increased risk of hippocampal calcifications. A greater degree of hippocampal calcifications was not associated with lower cognitive function in patients with memory complaints.

Histological validation of calcifications in the human hippocampus as seen on computed tomography.

BACKGROUND: Calcifications within the hippocampus were recently described for the first time on computed tomography (CT). These calcifications appeared in patients older than 50 years, the prevalence increases with age and they may be associated with cognitive decline. The aim of this study was to determine the histological basis (the presence, severity and location) of these CT-detected hippocampal calcifications of post-mortem brains. METHODS: CT scans of seven post-mortem brains were scored for the presence and severity (mild, moderate, severe) of hippocampal calcification. After this, samples from nine hippocampi (bilateral in two brains, unilateral in five brains) were stained with hematoxylin and eosin (HE) to indicate the cytoarchitecture, with Elastica van Gieson to analyse the elastic connective tissue of the vessel walls and with von Kossa for detection of calcium. RESULTS: In four brains (six hippocampi), calcifications were both found on CT and in corresponding histology. In three brains (three hippocampi), calcifications were absent on CT and corresponding histology. In histology, mild calcifications were located in the tail and severe calcifications involved the tail, body and sometimes the head of the hippocampus. The calcifications co-localised with precapillaries, capillaries and arteries of the molecular and granular layers of the dentate gyrus and the Cornu Ammonis 1. CONCLUSIONS: In this study, calcifications of the hippocampus as seen on CT scans were histologically located in vascular structures of the tail, body and head of the hippocampus.

Hippocampal calcification on brain CT: prevalence and risk factors in a cerebrovascular cohort.

OBJECTIVES: Recently, hippocampal calcification as observed on brain CT examinations was identified in over 20% of people over 50 years of age and a relation between hippocampal calcification and cognitive decline was shown. We determined the prevalence and investigated the vascular risk factors of hippocampal calcification in patients with cerebrovascular disease. METHODS: Hippocampal calcification was scored bilaterally on presence and severity on CT examinations in a cohort of 1130 patients with (suspected) acute ischaemic stroke. Multivariable logistic regression analysis, adjusting for age and gender as well as adjusting for multiple cardiovascular disease risk factors, was used to determine risk factors for hippocampal calcification. RESULTS: Hippocampal calcification was present in 381 (34%) patients. Prevalence increased with age from 8% below 40 to 45% at 80 years and older. In multivariable logistic regression analysis, age per decile (OR 1.41 [95% CI 1.26-1.57], p < 0.01), hypertension (OR 0.74 [95% CI 0.56-0.99], p = 0.049), diabetes mellitus (OR 1.57 [95% CI 1.10-2.25], p = 0.01) and hyperlipidaemia (OR 1.63 [95% CI 1.20-2.22], p < 0.01) were significantly associated with hippocampal calcification. CONCLUSIONS: Hippocampal calcification was a frequent finding on CT in this cohort of stroke patients and was independently positively associated with hyperlipidaemia and diabetes mellitus, suggesting an atherosclerotic origin. KEY POINTS: • Hippocampal calcification is prevalent in over 30% of cerebrovascular disease patients. • Prevalence increases from 8% below 40 to 45% over 80 years. • Hippocampal calcification is associated with cardiovascular risk factors hyperlipidaemia and diabetes mellitus.

Validation of an imaging based cardiovascular risk score in a Scottish population.

OBJECTIVES: A radiological risk score that determines 5-year cardiovascular disease (CVD) risk using routine care CT and patient information readily available to radiologists was previously developed. External validation in a Scottish population was performed to assess the applicability and validity of the risk score in other populations. METHODS: 2915 subjects aged ≥40 years who underwent routine clinical chest CT scanning for non-cardiovascular diagnostic indications were followed up until first diagnosis of, or death from, CVD. Using a case-cohort approach, all cases and a random sample of 20% of the participant's CT examinations were visually graded for cardiovascular calcifications and cardiac diameter was measured. The radiological risk score was determined using imaging findings, age, gender, and CT indication. RESULTS: Performance on 5-year CVD risk prediction was assessed. 384 events occurred in 2124 subjects during a mean follow-up of 4.25 years (0-6.4 years). The risk score demonstrated reasonable performance in the studied population. Calibration showed good agreement between actual and 5-year predicted risk of CVD. The c-statistic was 0.71 (95%CI:0.67-0.75). CONCLUSIONS: The radiological CVD risk score performed adequately in the Scottish population offering a potential novel strategy for identifying patients at high risk for developing cardiovascular disease using routine care CT data.

Computed Tomographic Distinction of Intimal and Medial Calcification in the Intracranial Internal Carotid Artery.

BACKGROUND: Intracranial internal carotid artery (iICA) calcification is associated with stroke and is often seen as a proxy of atherosclerosis of the intima. However, it was recently shown that these calcifications are predominantly located in the tunica media and internal elastic lamina (medial calcification). Intimal and medial calcifications are thought to have a different pathogenesis and clinical consequences and can only be distinguished through ex vivo histological analysis. Therefore, our aim was to develop CT scoring method to distinguish intimal and medial iICA calcification in vivo. METHODS: First, in both iICAs of 16 cerebral autopsy patients the intimal and/or medial calcification area was histologically assessed (142 slides). Brain CT images of these patients were matched to the corresponding histological slides to develop a CT score that determines intimal or medial calcification dominance. Second, performance of the CT score was assessed in these 16 patients. Third, reproducibility was tested in a separate cohort. RESULTS: First, CT features of the score were circularity (absent, dot(s), <90°, 90-270° or 270-360°), thickness (absent, ≥1.5mm, or <1.5mm), and morphology (indistinguishable, irregular/patchy or continuous). A high sum of features represented medial and a lower sum intimal calcifications. Second, in the 16 patients the concordance between the CT score and the dominant calcification type was reasonable. Third, the score showed good reproducibility (kappa: 0.72 proportion of agreement: 0.82) between the categories intimal, medial or absent/indistinguishable. CONCLUSIONS: The developed CT score shows good reproducibility and can differentiate reasonably well between intimal and medial calcification dominance in the iICA, allowing for further (epidemiological) studies on iICA calcification.

Hippocampal Calcification on Computed Tomography in Relation to Cognitive Decline in Memory Clinic Patients: A Case-Control Study.

BACKGROUND: It was recently shown that calcification of the hippocampus can be detected on computed tomography (CT) images and these calcifications occur in up to 20% of people over 50 years of age. However, little is known about hippocampal calcification and its relation to cognition and cognitive decline. Therefore, the aim of this study was to (1) determine the prevalence of hippocampal calcification on CT in memory clinic patients controls, and (2) to assess its relation with cognitive decline. METHODS: 67 patients from a memory clinic (cases) were matched by age and gender to a control group. In both groups, hippocampal calcification was assessed by two raters on thin slice, non-contrast enhanced brain CT images. Calcifications were scored bilaterally on presence and severity (absent, mild, moderate, severe). Mini Mental State Exam (MMSE) score was determined in cases. RESULTS: Hippocampal calcification presence was significantly higher in cases (N = 26, 38.8%) compared to controls (N = 9, 13.4%) (P < .01) with an odds ratio of 4.40 (95%CI: 1.63-14.87). In cases, MMSE score was significantly lower in those with hippocampal calcification compared to those without (21.6 vs 24.5, p = .02). CONCLUSION: In this case-control study we found significantly more hippocampal calcification in patients with cognitive decline as compared to controls. Furthermore, within the cases, MMSE score was significantly lower in those with hippocampal calcification.

Predominance of Nonatherosclerotic Internal Elastic Lamina Calcification in the Intracranial Internal Carotid Artery.

BACKGROUND AND PURPOSE: Calcification of the intracranial internal carotid artery (iICA) is an independent risk factor for stroke. These calcifications are generally seen as manifestation of atherosclerosis, but histological investigations are limited. The aim of this study is to determine whether calcifications in the iICA are present in atherosclerotic plaques, or in other parts of the arterial wall. METHODS: Thirty-nine iICAs were histologically assessed, using digital microscopy to quantify the amount of calcification in the different layers of the arterial wall. RESULTS: Calcifications were found in the intima, around the internal elastic lamina and in the medial layer of the arterial wall. In 71% of the arteries, internal elastic lamina calcification contributed most to the total calcified cross-sectional surface area. Internal elastic lamina calcification was unrelated to the occurrence of atherosclerotic intimal lesions. Intimal calcifications were most often associated with atherosclerotic lesions, but also many noncalcified atherosclerotic lesions were found. CONCLUSIONS: In the iICA, calcifications are predominantly present around the internal elastic lamina, suggesting that this nonatherosclerotic type of calcification contributes to the previously observed increased risk of stroke in patients with iICA calcifications.

Low-Dose Pelvic Computed Tomography Using Adaptive Iterative Dose Reduction 3-Dimensional Algorithm: A Phantom Study.

OBJECTIVE: To evaluate the image quality and radiation dose reduction in pelvic computed tomography (CT) achieved with an adaptive iterative dose reduction 3-dimensional (AIDR 3D) algorithm using a phantom model. METHODS: Two phantoms were scanned using a 320-detector row CT scanner with 8 tube current levels, and the images were reconstructed with a standard filtered back projection (FBP) algorithm and with an AIDR 3D algorithm. RESULTS: Compared with FBP, AIDR 3D reduced image noise and improved contrast-to-noise ratios. The diagnostic performance for detection of low-contrast targets of AIDR 3D images obtained with 100 mA at 120 kVp was almost as good as that of the FBP images obtained with 200 mA. CONCLUSIONS: The AIDR 3D algorithm substantially reduced image noise and improved the image quality of pelvic CT images compared with those obtained with the FBP algorithm and can thus be considered a promising technique for low-dose pelvic CT examinations.