Pituitary Apoplexy in Macroadenoma After Minor Surgery: An Unusual Case and Literature Review.

Pituitary apoplexy is a rare and severe complication of pituitary adenoma that may present with new-onset headache, ocular palsy, visual disturbances, life-threatening electrolyte imbalance, and endocrinological disturbances due to pituitary hemorrhage and/or infarction. We report the case of a 58-year-old previously healthy patient who developed isolated mild oculomotor nerve palsy of the left eye following osteosynthesis of a traumatic right distal radius fracture. Initial cerebral magnetic resonance imaging showed a pituitary macroadenoma without characteristic signs of pituitary infarction or hemorrhage. The patient presented to the neurology department on the fifth postoperative day with malaise and fatigue due to pituitary insufficiency, deteriorated rapidly and required intensive care monitoring. Clinical stabilization was achieved through the administration of hydrocortisone, and transsphenoidal resection of the pituitary lesion was performed on the 10th day after acute symptom onset. Histological examination revealed a necrotic pituitary adenoma. Pituitary apoplexy may occur after minor surgery in patients with pituitary adenoma. Clinicians should pay particular attention to laboratory signs of pituitary insufficiency in new-onset oculomotor nerve palsy associated with sellar lesions, as cerebral imaging may miss pituitary apoplexy and therefore delay diagnosis and treatment. In our case, delayed decompressive transsphenoidal resection resulted in the normalization of the oculomotor nerve palsy while the pituitary insufficiency persisted. The potential impact of an earlier surgical intervention on the outcome of pituitary function remains uncertain.

Meningeal Metastasis Causing Chronic Subdural Hematoma in a Cancer Patient with Bilateral Papilledema and Suspected Cerebral Venous Thrombosis: A Case Report.

Meningeal metastasis has been reported as a very rare cause of chronic subdural hematoma (CSH). Here, we report a female patient who had undergone initial burr hole drainage of a CSH at an outside hospital. Postoperatively, the patient additionally suffered from visual impairment due to bilateral papilledema and the patient was eventually transferred to our neurosurgical department for additional treatment. A craniotomy was performed and due to intraoperative suspicious findings, histopathologic samples were obtained that revealed a metastasis of thus far undiagnosed triple negative breast cancer. Furthermore, the patient was suspected to have a partial cerebral venous thrombosis (CVT). Our case report addresses this extremely rare clinical constellation. We provide a detailed overview on our patient's clinical and radiologic course, and discuss the potential association of CSH with meningeal metastasis and bilateral papilledema.

Evaluation of a novel flow diverter, the DiVeRt system, in an animal model.

BACKGROUND: Using a surgical aneurysm model, this study assessed the performance of a new flow diverter (FD), the DiVeRt, and evaluated the angiographic and histologic features at different periods after stent deployment. METHODS: Fifteen New Zealand White rabbits were treated 3 days prior to intervention and until euthanization with dual antiplatelets. DiVeRt was implanted in bilateral carotid aneurysms (n=30) as well as in the aorta (n=15). The rate of technical success, assessment of aneurysm occlusion (measured by the O'Kelly-Marotta grading (OKM) scale), and stent patency were examined using angiography and histologic examinations in three groups at 1, 3, and 6 months follow-up (FU). In each FU group one control animal was included and treated with the XCalibur stent (n=3). RESULTS: Overall, DiVeRt placement was successful and without apparent intraprocedural complications. In total, four stents in the carotid artery were occluded and in-stent stenosis was registered in two carotid (7%) and one aortic (6%) vessels. Complete or near complete aneurysm occlusion (OKM scale D1 and C3) was seen in 100% in the 1-month FU group, 70% in the 2-month FU group, and 100% in the 3-month FU group. Histology showed loose, organizing fibrous tissue matrix within the sac and adequate neck endothelialization in all vessels. All branches covered by the DiVeRt remained patent. CONCLUSIONS: The DiVeRt system appears to be feasible and effective for the treatment of aneurysms with high rates of complete aneurysm occlusion, excellent vessel patency, and evidence of high biocompatibility. Occurrences of parent artery occlusion at follow-up did not result in clinical consequences.

Tetravalent Influenza Vaccine Is Not Associated With Neuroaxonal Damage in Multiple Sclerosis Patients.

Background: Efficacy of vaccines and disease activity linked to immunization are major concerns among people with multiple sclerosis (pwMS). Objective: To assess antibody responses to seasonal influenza antigens and vaccine-associated neuroaxonal damage utilizing serum neurofilament light chain (sNfL) in pwMS receiving dimethyl fumarate (DMF). Methods: In this prospective study, the 2020/2021 seasonal tetravalent influenza vaccine was administered to 20 pwMS treated with DMF and 15 healthy controls (HCs). The primary endpoints were responder rate of strain-specific antibody production (seroconversion or significant (4-fold) increase in influenza-antibody titers for ≥2/4 strains) at 30 days post-vaccination and changes in sNfL levels. Results: All patients treated with DMF fulfilled the responder criteria for immunization compared with 53% of the controls. However, higher proportions of HCs already had influenza-antibody titers ≥1:40 at baseline (53% vs. 41%, p = 0.174). sNfL levels were comparable among both groups at baseline and did not increase 34 days after vaccination. In addition, no clinical or radiological disease reactivation was found. Conclusion: DMF-treated patients mount an adequate humoral immune response to influenza vaccines. Within the limits of the small cohort investigated, our data suggest that influenza immunization is not associated with clinical or subclinical disease reactivation.

Neck-MRI experience for investigation of survived strangulation victims.

For the medicolegal evaluation of victims of survived strangulation, a neck-magnetic resonance imaging (MRI) can be performed for assessing lesions in the inner soft tissues (fat, muscles or lymph nodes, for example). In our institute, such MRI examinations have been performed for a test period of 4 years with the aim of evaluating the use of this tool by forensic pathologists and identifying medicolegal indicators for the performance of neck-MRI in surviving victims of strangulation. We retrospectively reviewed medicolegal reports from all victims examined during the test period. We extracted objective lesions (e.g. petechiae, bruising and abrasions) and reported clinical symptoms (e.g. vision disorder, dysphasia) from the reports. These findings were compared to those reported from the neck-MRI. In total, 112 victims were clinically examined after suspected strangulation. Eleven of these victims underwent an MRI examination of the neck. Eighty-four of the victims presented objective lesions during the clinical examination, with eight showing signs of both petechiae and bruising. Neck-MRI was performed in four of these eight victims and three of them showed lesions visible in MRI. Of 76 victims with bruising as the only objective finding, 66 victims described clinical symptoms. Of those 66 victims, seven were examined by MRI and two demonstrated lesions in MRI. When MRI was performed, relevant findings were detected in 45% of the cases. This leads to the suspicion that many more findings could have been detected in the other victims, if an MRI had been performed in those cases. Our results lead us to the conclusion that an MRI examination of victims of suspected strangulation is useful, and strict indications for its application should be established.

Postmortem CT Angiography Compared with Autopsy: A Forensic Multicenter Study.

Purpose To determine if postmortem computed tomography (CT) and postmortem CT angiography help to detect more lesions than autopsy in postmortem examinations, to evaluate the strengths and weaknesses of each method, and to define their indications. Materials and Methods Postmortem CT angiography was performed on 500 human corpses and followed by conventional autopsy. Nine centers were involved. All CT images were read by an experienced team including one forensic pathologist and one radiologist, blinded to the autopsy results. All findings were recorded for each method and categorized by anatomic structure (bone, organ parenchyma, soft tissue, and vascular) and relative importance in the forensic case (essential, useful, and unimportant). Results Among 18 654 findings, autopsies helped to identify 61.3% (11 433 of 18 654), postmortem CT helped to identify 76.0% (14 179 of 18 654), and postmortem CT angiography helped to identify 89.9% (16 780 of 18 654; P < .001). Postmortem CT angiography was superior to autopsy, especially at helping to identify essential skeletal lesions (96.1% [625 of 650] vs 65.4% [425 of 650], respectively; P < .001) and vascular lesions (93.5% [938 of 1003] vs 65.3% [655 of 1003], respectively; P < .001). Among the forensically essential findings, 23.4% (1029 of 4393) were not detected at autopsy, while only 9.7% (428 of 4393) were missed at postmortem CT angiography (P < .001). The best results were obtained when postmortem CT angiography was combined with autopsy. Conclusion Postmortem CT and postmortem CT angiography and autopsy each detect important lesions not detected by the other method. More lesions were identified by combining postmortem CT angiography and autopsy, which may increase the quality of postmortem diagnosis. Online supplemental material is available for this article.

Fat-free muscle mass in magnetic resonance imaging predicts acute-on-chronic liver failure and survival in decompensated cirrhosis.

Muscle mass seems to be a prognostic marker in patients with liver cirrhosis. However, reported methods to quantify muscle mass are heterogeneous, consented cutoff values are missing, and most studies have used computed tomography. This study evaluated fat-free muscle area (FFMA) as a marker of sarcopenia using magnetic resonance imaging (MRI) in patients with decompensated cirrhosis with transjugular intrahepatic portosystemic shunt (TIPS). The total erector spinae muscle area and the intramuscular fat tissue area were measured and subtracted to calculate the FFMA in 116 patients with cirrhosis by TIPS and MRI. The training cohort of 71 patients compared computed tomography-measured transversal psoas muscle thickness with FFMA. In 15 patients MRI was performed before and after TIPS, and in 12 patients follistatin serum measurements were carried out. The results on FFMA were confirmed in a validation cohort of 45 patients. FFMA correlated with follistatin and transversal psoas muscle thickness and showed slightly better association with survival than transversal psoas muscle thickness. Gender-specific cutoff values for FFMA were determined for sarcopenia. Decompensation (ascites, overt hepatic encephalopathy) persisted after TIPS in the sarcopenia group but resolved in the nonsarcopenia group. Sarcopenic patients showed no clinical improvement after TIPS as well as higher mortality, mainly due to development of acute-on-chronic liver failure. FFMA was an independent predictor of survival in these patients. CONCLUSION: This study offers an easy-to-apply MRI-based measurement of fat-free muscle mass as a marker of sarcopenia in decompensated patients; while TIPS might improve sarcopenia and thereby survival, persistence of sarcopenia after TIPS is associated with a reduced response to TIPS and a higher risk of acute-on-chronic liver failure development and mortality. (Hepatology 2018;67:1014-1026).

Influence of model based iterative reconstruction algorithm on image quality of multiplanar reformations in reduced dose chest CT.

BACKGROUND: Model-based iterative reconstruction (MBIR) reduces image noise and improves image quality (IQ) but its influence on post-processing tools including maximal intensity projection (MIP) and minimal intensity projection (mIP) remains unknown. PURPOSE: To evaluate the influence on IQ of MBIR on native, mIP, MIP axial and coronal reformats of reduced dose computed tomography (RD-CT) chest acquisition. MATERIAL AND METHODS: Raw data of 50 patients, who underwent a standard dose CT (SD-CT) and a follow-up RD-CT with a CT dose index (CTDI) of 2-3 mGy, were reconstructed by MBIR and FBP. Native slices, 4-mm-thick MIP, and 3-mm-thick mIP axial and coronal reformats were generated. The relative IQ, subjective IQ, image noise, and number of artifacts were determined in order to compare different reconstructions of RD-CT with reference SD-CT. RESULTS: The lowest noise was observed with MBIR. RD-CT reconstructed by MBIR exhibited the best relative and subjective IQ on coronal view regardless of the post-processing tool. MBIR generated the lowest rate of artefacts on coronal mIP/MIP reformats and the highest one on axial reformats, mainly represented by distortions and stairsteps artifacts. CONCLUSION: The MBIR algorithm reduces image noise but generates more artifacts than FBP on axial mIP and MIP reformats of RD-CT. Conversely, it significantly improves IQ on coronal views, without increasing artifacts, regardless of the post-processing technique.

Performance of post-mortem CT compared to autopsy in children.

INTRODUCTION: Radiological techniques such as non-enhanced post-mortem computed tomography (PMCT) play an increasingly important role in death investigations, especially in cases of non-medicolegal context of death, where the consent of the next of kin is required to perform autopsy. Such consent is often difficult to obtain for deceased children, and radiological methods may be an acceptable alternative. The aim of our study was to evaluate the performance of PMCT explorations compared to medicolegal conventional autopsies in children and its potential usefulness in non-medicolegal situations. METHODS: We retrospectively reviewed a group of 26 children aged 0-12 years who died of different causes, which were investigated by both conventional autopsy and PMCT. We compared the findings extracted from radiological and autopsy reports. All findings were grouped according to their importance with respect to cause of death and to the anatomical structure they covered: organs, vascular system, soft tissue, and skeletal system. RESULTS: A significantly larger number of findings were detected by autopsy compared to PMCT. Autopsy proved to be superior to PMCT, notably at detecting organ, soft tissue, and vascular findings, while PMCT was superior at detecting bone findings. However, no statistically significant differences were found between the methods concerning the essential findings used to define the cause of death. CONCLUSIONS: In children, PMCT was less sensitive than conventional autopsy for detecting general findings. However, most essential findings were detected by both methods. PMCT was superior to autopsy for the detection of bone lesions in children. ADVANCES IN KNOWLEDGE: Up to today, very rare literature exists concerning PMCT in children, especially in a forensic setting. This article investigates the advantages and limitations of PMCT compared to autopsy in a unique study group and discusses possibilities for future developments.

Application of contrast media in post-mortem imaging (CT and MRI).

The application of contrast media in post-mortem radiology differs from clinical approaches in living patients. Post-mortem changes in the vascular system and the absence of blood flow lead to specific problems that have to be considered for the performance of post-mortem angiography. In addition, interpreting the images is challenging due to technique-related and post-mortem artefacts that have to be known and that are specific for each applied technique. Although the idea of injecting contrast media is old, classic methods are not simply transferable to modern radiological techniques in forensic medicine, as they are mostly dedicated to single-organ studies or applicable only shortly after death. With the introduction of modern imaging techniques, such as post-mortem computed tomography (PMCT) and post-mortem magnetic resonance (PMMR), to forensic death investigations, intensive research started to explore their advantages and limitations compared to conventional autopsy. PMCT has already become a routine investigation in several centres, and different techniques have been developed to better visualise the vascular system and organ parenchyma in PMCT. In contrast, the use of PMMR is still limited due to practical issues, and research is now starting in the field of PMMR angiography. This article gives an overview of the problems in post-mortem contrast media application, the various classic and modern techniques, and the issues to consider by using different media.

Pathomorphological and CT-angiographical characteristics of coronary atherosclerotic plaques in cases of sudden cardiac death.

The goal of this study was to assess the localization and types of thrombosed plaques in cases of sudden cardiac death attributed to coronary artery disease and to evaluate possible correlations with body mass index (BMI) and increased heart weight. This retrospective study was performed on forensic cases for which the cause of death was attributed to coronary artery disease. A complete autopsy and a multi-phase postmortem computed tomography (CT) angiography (MPMCTA) were performed in all cases. Eighty-five cases were selected (mean age, 55.18 ± 11.04 years; 72 men and 13 women). MPMCTA performed prior to autopsy enabled an evaluation of coronary artery perfusion before dissection of the body and helped therefore to guide sampling for histology. An acute coronary thrombosis was found in 57 cases, which included plaque erosion in 26 cases (mean age, 46.73 ± 8.33 years) and rupture or intra-plaque hemorrhage in 31 cases (mean age, 58.23 ± 10.62 years). Erosions were most frequently found in the left anterior descending artery (61.5%), while only 35.48% of ruptures were observed in this artery. Chronic coronary pathology was considered as the main cause of death in 28 cases (mean age, 59.64 ± 9.47 years). Sixty-two of the cases (72.94%) had a BMI in the overweight category (BMI ≥25), with the highest mean BMI in patients with chronic coronary pathology without acute thrombosis found at autopsy. The heart weight was above the predicted reference values in 52 cases (61.18%). Our results are in accordance with previously published studies on the spatial distribution of vulnerable plaques. We observed a higher percentage of eroded plaques than previously reported. Patients with coronary erosions were significantly younger than those with plaque rupture or those without an acute coronary thrombosis (p values <0.0001). BMI and heart weight were significantly higher for cases without thrombosis in comparison with those with plaque rupture (p values 0.028 and 0.003, respectively). Our results indicating that increased BMI and overweight hearts are associated with chronic ischemic heart disease are compatible with clinical studies. Performing more postmortem studies on forensic autopsies, including modern radiological examinations with MPMCTA, can enhance the detection of vulnerable plaques in living patients and prevent sudden cardiac death.

Computed tomography angiography vs 3 T black-blood cardiovascular magnetic resonance for identification of symptomatic carotid plaques.

BACKGROUND: The purpose of this prospective study was to perform a head-to-head comparison of the two methods most frequently used for evaluation of carotid plaque characteristics: Multi-detector Computed Tomography Angiography (MDCTA) and black-blood 3 T-cardiovascular magnetic resonance (bb-CMR) with respect to their ability to identify symptomatic carotid plaques. METHODS: 22 stroke unit patients with unilateral symptomatic carotid disease and >50% stenosis by duplex ultrasound underwent MDCTA and bb-CMR (TOF, pre- and post-contrast fsT1w-, and fsT2w- sequences) within 15 days of symptom onset. Both symptomatic and contralateral asymptomatic sides were evaluated. By bb-CMR, plaque morphology, composition and prevalence of complicated AHA type VI lesions (AHA-LT6) were evaluated. By MDCTA, plaque type (non-calcified, mixed, calcified), plaque density in HU and presence of ulceration and/or thrombus were evaluated. Sensitivity (SE), specificity (SP), positive and negative predictive value (PPV, NPV) were calculated using a 2-by-2-table. RESULTS: To distinguish between symptomatic and asymptomatic plaques AHA-LT6 was the best CMR variable and presence / absence of plaque ulceration was the best CT variable, resulting in a SE, SP, PPV and NPV of 80%, 80%, 80% and 80% for AHA-LT6 as assessed by bb-CMR and 40%, 95%, 89% and 61% for plaque ulceration as assessed by MDCTA. The combined SE, SP, PPV and NPV of bb-CMR and MDCTA was 85%, 75%, 77% and 83%, respectively. CONCLUSIONS: Bb-CMR is superior to MDCTA at identifying symptomatic carotid plaques, while MDCTA offers high specificity at the cost of low sensitivity. Results were only slightly improved over bb-CMR alone when combining both techniques.

Differentiation of heroin and cocaine using dual-energy CT-an experimental study.

OBJECTIVE: To evaluate if heroin and cocaine can be distinguished using dual-energy CT. MATERIALS AND METHODS: Twenty samples of heroin and cocaine at different concentrations and standardized compression (SC) were scanned in dual-energy mode on a newest generation Dual Energy 64-row MDCT scanner. CT number, spectral graphs, and dual-energy index (DEI) were evaluated. Results were prospectively tested on six original samples from a body packer. Wilcoxon's test was used for statistical evaluation. RESULTS: Values are given as median and range. Under SC, the CT number of cocaine samples (-29.87 Hounsfield unit (HU) [-125.85; 16.16 HU]) was higher than the CT number of heroin samples (-184.37 HU [-199.81; -159.25 HU]; p < 0.01). Slope of spectral curves for cocaine was -2.36 HU/keV [-7.15; -0.67 HU/keV], and for heroin, 1.75 HU/keV [1.28; 2.5 HU/keV] (p < 0.01). DEI was 0.0352 [0.0081; 0.0528] for cocaine and significantly higher than for heroin samples (-0.0127 [-0.0097; -0.0159]; p < 0.001). While CT number was inconclusive, all six original packs were correctly classified after evaluation of the spectral curve and DEI. In contrast to the CT number, slope of the spectral curve and DEI were independent of concentration and compression. CONCLUSION: The slope of the spectral curve and the DEI from dual-energy CT data can be used to distinguish heroin and cocaine in vitro; these results are independent of compression and concentration in the measured range.

Iterative image reconstruction techniques: cardiothoracic computed tomography applications.

Iterative image reconstruction algorithms provide significant improvements over traditional filtered back projection in computed tomography (CT). Clinically available through recent advances in modern CT technology, iterative reconstruction enhances image quality through cyclical image calculation, suppressing image noise and artifacts, particularly blooming artifacts. The advantages of iterative reconstruction are apparent in traditionally challenging cases-for example, in obese patients, those with significant artery calcification, or those with coronary artery stents. In addition, as clinical use of CT has grown, so have concerns over ionizing radiation associated with CT examinations. Through noise reduction, iterative reconstruction has been shown to permit radiation dose reduction while preserving diagnostic image quality. This approach is becoming increasingly attractive as the routine use of CT for pediatric and repeated follow-up evaluation grows ever more common. Cardiovascular CT in particular, with its focus on detailed structural and functional analyses, stands to benefit greatly from the promising iterative solutions that are readily available.

Endoleak and in-stent thrombus detection with CT angiography in a thoracic aortic aneurysm phantom at different tube energies using filtered back projection and iterative algorithms.

PURPOSE: To determine the lower limit of dose reduction with hybrid and fully iterative reconstruction algorithms in detection of endoleaks and in-stent thrombus of thoracic aorta with computed tomographic (CT) angiography by applying protocols with different tube energies and automated tube current modulation. MATERIALS AND METHODS: The calcification insert of an anthropomorphic cardiac phantom was replaced with an aortic aneurysm model containing a stent, simulated endoleaks, and an intraluminal thrombus. CT was performed at tube energies of 120, 100, and 80 kVp with incrementally increasing noise indexes (NIs) of 16, 25, 34, 43, 52, 61, and 70 and a 2.5-mm section thickness. NI directly controls radiation exposure; a higher NI allows for greater image noise and decreases radiation. Images were reconstructed with filtered back projection (FBP) and hybrid and fully iterative algorithms. Five radiologists independently analyzed lesion conspicuity to assess sensitivity and specificity. Mean attenuation (in Hounsfield units) and standard deviation were measured in the aorta to calculate signal-to-noise ratio (SNR). Attenuation and SNR of different protocols and algorithms were analyzed with analysis of variance or Welch test depending on data distribution. RESULTS: Both sensitivity and specificity were 100% for simulated lesions on images with 2.5-mm section thickness and an NI of 25 (3.45 mGy), 34 (1.83 mGy), or 43 (1.16 mGy) at 120 kVp; an NI of 34 (1.98 mGy), 43 (1.23 mGy), or 61 (0.61 mGy) at 100 kVp; and an NI of 43 (1.46 mGy) or 70 (0.54 mGy) at 80 kVp. SNR values showed similar results. With the fully iterative algorithm, mean attenuation of the aorta decreased significantly in reduced-dose protocols in comparison with control protocols at 100 kVp (311 HU at 16 NI vs 290 HU at 70 NI, P ≤ .0011) and 80 kVp (400 HU at 16 NI vs 369 HU at 70 NI, P ≤ .0007). CONCLUSION: Endoleaks and in-stent thrombus of thoracic aorta were detectable to 1.46 mGy (80 kVp) with FBP, 1.23 mGy (100 kVp) with the hybrid algorithm, and 0.54 mGy (80 kVp) with the fully iterative algorithm.

Low-dose CT in body-packers: delineation of body packs and radiation dose in a porcine model.

PURPOSE: To compare low-dose computed tomography (CT) with standard CT and conventional radiography (CR) regarding delineation of body packs and radiation dose. METHODS: Nine samples of illicit drugs including cocaine, heroin, and hashish were positioned in the rectum of a 121.5 kg pig cadaver. Each sample was scanned on a 64-row MDCT with 120 kV: one standard modulated pelvic protocol (STD), and without modulation at 80 mA (LD80), 30 mA (LD30), and 10 mA (LD10). Additionally, conventional abdominal anterior-posterior radiographs (77 kV and 106 ± 13 mA) were taken. Body pack characteristics (wrapping, content, shape) were rated independently by two radiologists and summarized to a delineation score from 0 to 9 with scores ≥6 representing sufficient delineation. Mean delineation scores were calculated for CR and CT protocols. These were additionally differentiated for readings in soft tissue (S), lung (L), user defined, variable window settings (V), and in cumulative window evaluation including all the other window settings (SLV). Effective doses were calculated (mSv). RESULTS: The CR delineation score was insufficient (3.1 ± 2.5; 2.4 ± 0.3 mSv). For CT, the SLV window setting performed best (p < 0.01). Its score significantly (p < 0.01) declined with decreasing effective radiation doses: STD (8.8 ± 0.5; 10.6 mSv), LD80 (8.2 ± 0.7; 2.6 mSv), LD30 (6.8 ± 1.3; 1.0 mSv), and LD10 (4.6 ± 1.9; 0.3 mSv). Thus, LD30 was the protocol using the lowest but sufficient dose. Moreover, for LD30 further differentiation between the particular window settings resulted in scores of 6.4 ± 1.3 (L), 6.3 ± 1.2 (V), and 3.1 ± 1.0 (S). CONCLUSIONS: With appropriate window settings, low-dose CT at 30 mA allowed for sufficient body-pack delineation below the dose of CR, which itself performed insufficient.

Comparison of symptomatic and asymptomatic atherosclerotic carotid plaques using parallel imaging and 3 T black-blood in vivo CMR.

BACKGROUND: To determine if black-blood 3 T cardiovascular magnetic resonance (bb-CMR) can depict differences between symptomatic and asymptomatic carotid atherosclerotic plaques in acute ischemic stroke patients. METHODS: In this prospective monocentric observational study 34 patients (24 males; 70 ±9.3 years) with symptomatic carotid disease defined as ischemic brain lesions in one internal carotid artery territory on diffusion weighted images underwent a carotid bb-CMR at 3 T with fat-saturated pre- and post-contrast T1w-, PDw-, T2w- and TOF images using surface coils and Parallel Imaging techniques (PAT factor = 2) within 10 days after symptom onset. All patients underwent extensive clinical workup (lab, brain MR, duplex sonography, 24-hour ECG, transesophageal echocardiography) to exclude other causes of ischemic stroke. Prevalence of American Heart Association lesion type VI (AHA-LT6), status of the fibrous cap, presence of hemorrhage/thrombus and area measurements of calcification, necrotic core and hemorrhage were determined in both carotid arteries in consensus by two reviewers who were blinded to clinical information. McNemar and Wilcoxon's signed rank tests were use for statistical comparison. A p-value <0.05 was considered statistically significant. RESULTS: Symptomatic plaques showed a higher prevalence of AHA-LT6 (67.7% vs. 11.8%; p < 0.001; odds ratio = 12.5), ruptured fibrous caps (44.1% vs. 2.9%; p < 0.001; odds ratio = 15.0), juxtaluminal thrombus (26.5 vs. 0%; p < 0.01; odds ratio = 7.3) and intraplaque hemorrhage (58.6% vs. 11.8%; p = 0.01; odds ratio = 3.8). Necrotic core and hemorrhage areas were greater in symptomatic plaques (14.1 mm2 vs. 5.5 mm2 and 13.6 mm2 vs. 5.3 mm2; p < 0.01, respectively). CONCLUSION: 3 T bb-CMR is able to differentiate between symptomatic and asymptomatic carotid plaques, demonstrating the potential of bb-CMR to differentiate between stable and vulnerable lesions and ultimately to identify patients with low versus high risk for cardiovascular complications. Best predictors of the symptomatic side were a ruptured fibrous cap, AHA-LT 6, juxtaluminal hemorrhage/thrombus, and intraplaque hemorrhage.

Filtered back projection, adaptive statistical iterative reconstruction, and a model-based iterative reconstruction in abdominal CT: an experimental clinical study.

PURPOSE: To compare objective and subjective image quality parameters of three image reconstruction algorithms of different generations at routine multidetector computed tomographic (CT) examinations of the abdomen. MATERIALS AND METHODS: This institutional review board-approved study included 22 consecutive patients (mean age, 56.1 years ± 15.8 [standard deviation]; mean weight, 79.1 kg ± 14.8) who underwent routine CT examinations of the abdomen. A low-contrast phantom was used for objective quality control. Raw data sets were reconstructed by using filtered back projection (FPB), adaptive statistical iterative reconstruction (ASIR), and a model-based iterative reconstruction (MBIR). Radiologists used a semiquantitative scale (-3 to +3) to rate subjective image quality and artifacts, comparing both FBP and MBIR images with ASIR images. The Wilcoxon test and the intraclass correlation coefficient were used to evaluate the data. Measurements of objective noise and CT numbers of soft tissue structures were compared with analysis of variance. RESULTS: The phantom study revealed an improved detectability of low-contrast targets for MBIR compared with ASIR or FBP. Subjective ratings showed higher image quality for MBIR, with better resolution (median value, 2; range, 1 to 3), lower noise (2; range, 1 to 3), and finer contours (2; range, 1 to 2) compared with ASIR (all P < .001). FBP performed inferiorly (0, range, -2 to 0]; -1 [range, -3 to 0]; 0 [range, -1 to 0], respectively; all, P < .001). Mean interobserver correlation was 0.9 for image perception and 0.7 for artifacts. Objective noise for FBP was 14%-68% higher and for MBIR was 18%-47% lower than that for ASIR (P < .001). CONCLUSION: The MBIR algorithm considerably improved objective and subjective image quality parameters of routine abdominal multidetector CT images compared with those of ASIR and FBP.