Search

Purpose To compare attenuation measurements and image quality of virtual unenhanced phase (VUP) images with those of conventional true unenhanced phase (TUP) images on spectral dual energy computed tomography (DECT) with dual layer detector on abdominal tissues and to assess potential reduction in radiation dose. Material and method A total of 295 patients (185 men, 110 women; mean age 61 ± 17.6 [SD] years [range: 17–95 years]) who had undergone abdominal or thoraco-abdominal CT with pre- and post-contrast imaging (portal phase) with spectral DECT with dual layer detector were retrospectively analyzed. VUP images based on portal-venous phase DECT acquisition were generated. Regions of interest were defined in abdominal tissues (liver, spleen, kidney, muscle and fat) by two independent readers. Inter-technique agreement (VUP images vs. TUP images) on attenuation measurements was assessed. Signal-to noise ratio (SNR) and image quality of TUP and VUP images were compared. The radiation dose delivered to patients was compared with the radiation dose of protocols without TUP images. Results A total of 9880 ROIs were drawn in the abdominal tissues. The difference in mean attenuation values between TUP and VUP images was less than 15 HU in 98.3% and less than 10 HU in 92.3% of all measurements. VUP images overestimated attenuation in fat comparatively to TUP images. Image quality was evaluated as good or excellent in 77% (37/48) of TUP images and 54% (26/48) of VUP images. Using VUP images instead of TUP images could decrease the radiation dose by 32%. Conclusion VUP images demonstrate good agreement with TUP images in different abdominals tissues and can be obtained with similar image quality as TUP. VUP images appear as an alternative to TUP images, resulting in reduction of radiation dose delivered to the patient.

Whether segmental or diffuse, a hepatofugal blood flow is almost always pathological. Over the years, Doppler ultrasonography has retained its position as one of the most accessible and physiological imaging techniques to evaluate the direction of the portal blood flow. Detection of a reverse flow is important as it may change patient care and outcome.

OBJECTIVES: Intramammary mass lesions are reportedly present in up to 5.8% of all contrast enhanced CT-examinations of the female chest. We aimed to assess whether their biological relevance can be estimated using spectral CT-datasets. METHODS: In this bicentric retrospective study patients with breast masses visualized on spectral CT-examinations from 07/2017 to 06/2019 were included. Lesions were characterized as malignant or benign based on histology and/or a stable follow-up of >2 years. Conventional CT-images, iodine density-maps, virtual monoenergetic-images (40 keV, 100 keV) and Zeffective-maps were evaluated by two independent readers. Statistical analysis derived from the Regions of interest (ROIs) was done by calculating the Areas under the Receiver operating characteristic (ROC) curve (AUC) and Youden-indices. RESULTS: 106 breast masses (malignant/benign: 81/25, 76.4%/23.6%) were included. The mean AUCs of the variables "iodine content" (reader 1/2:0.97;0.98), "monoenergetic curve-slope" (0.97;0.96) and "Zeffective" (0.98;0.98) measured in the target lesions (TL) showed superior results compared to those derived from the variable "density" (0.92;0.93) (p < 0.001). The ratios "TL to aorta" calculated for the variables "iodine content", "monoenergetic curve-slope" and "Zeffective" showed superior results compared to normal breast tissue and muscle (p < 0.001). The optimal cutpoint for the "iodine content" in the TL was 0.7-0.9 mg/ml (sensitivity 96.6%, specificity 91.7%). The best diagnostic results were achieved by normalizing the iodine content in the TL to that in the aorta (optimal cutpoint 0.1, sensitivity 95.5%, 98.9%, specificity 91.7%). CONCLUSIONS: Our preliminary results suggest that spectral CT-datasets might allow to estimate the biological dignity of breast masses detected on clinically indicated chest-examinations.

Coronavirus disease 2019 (COVID-19) is commonly associated with kidney damage, and the angiotensin converting enzyme 2 (ACE2) receptor for SARS-CoV-2 is highly expressed in the proximal tubule cells. Whether patients with COVID-19 present specific manifestations of proximal tubule dysfunction remains unknown. To test this, we examined a cohort of 49 patients requiring hospitalization in a large academic hospital in Brussels, Belgium. There was evidence of proximal tubule dysfunction in a subset of patients with COVID-19, as attested by low-molecular-weight proteinuria (70-80%), neutral aminoaciduria (46%), and defective handling of uric acid (46%) or phosphate (19%). None of the patients had normoglycemic glucosuria. Proximal tubule dysfunction was independent of pre-existing comorbidities, glomerular proteinuria, nephrotoxic medications or viral load. At the structural level, kidneys from patients with COVID-19 showed prominent tubular injury, including in the initial part of the proximal tubule, with brush border loss, acute tubular necrosis, intraluminal debris, and a marked decrease in the expression of megalin in the brush border. Transmission electron microscopy identified particles resembling coronaviruses in vacuoles or cisternae of the endoplasmic reticulum in proximal tubule cells. Among features of proximal tubule dysfunction, hypouricemia with inappropriate uricosuria was independently associated with disease severity and with a significant increase in the risk of respiratory failure requiring invasive mechanical ventilation using Cox (adjusted hazard ratio 6.2, 95% CI 1.9-20.1) or competing risks (adjusted sub-distribution hazard ratio 12.1, 95% CI 2.7-55.4) survival models. Thus, our data establish that SARS-CoV-2 causes specific manifestations of proximal tubule dysfunction and provide novel insights into COVID-19 severity and outcome., Graphical abstract

Teaching point: Intra-osseous access for contrast medium injection represents an alternative route for emergency CT in patients with compromised venous access.

Objectives As severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) pandemic is increasing its victims on a global scale with recurring outbreaks, it remains of outmost importance to rapidly identify people requiring an intensive care unit (ICU) hospitalization. The aim of this study was to identify Coronavirus Disease 2019 (COVID-19) biomarkers, to investigate their correlation with disease severity and to evaluate their usefulness for follow-up. Methods Fifty patients diagnosed with SARS-Cov-2 were included in March 2020. Clinical and biological data were collected at admission, during hospitalization and one month after discharge. Patients were divided into two severity groups: non-ICU (28) and ICU and/or death (22) to stratify the risk. Results Blood parameters in COVID-19 patients at admission showed increased C-reactive protein (CRP) (100%), ferritin (92%), lactate dehydrogenase (LDH) (80%), white blood cell (WBC) count (26%) with lymphopenia (52%) and eosinopenia (98%). There were significant differences in levels of CRP, ferritin, D-dimers, fibrinogen, lymphocyte count, neutrophil count and neutrophil-to-lymphocyte ratio (NLR) among the two severity groups. Mapping of biomarker’s kinetics distinguished early and late parameters. CRP, ferritin, LDH, lymphopenia and eosinopenia were present upon admission with a peak at the first week. Late biomarkers such as anemia, neutrophilia and elevated liver biomarkers appeared after one week with a peak at three weeks of hospitalization. Conclusions We confirmed that high-values of CRP, NLR, D-dimers, ferritin as well as lymphopenia and eosinopenia were consistently found and are good markers for risk stratification. Kinetics of these biomarkers correlate well with COVID-19 severity. Close monitoring of early and late biomarkers is crucial in the management of critical patients to avoid preventable deaths.

Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections. The most commonly encountered pathogens during this period are gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa …), but gram-positive coccus such as Staphylococcus aureus or Streptococcus pneumoniae and anaerobic bacteria can also be found. Empirical antibiotic therapy should be guided by previous colonisation of the recipient and bacterial resistance pattern in the hospital. Six months after transplantation, pneumonias are mostly due to community-acquired bacteria (S. pneumonia, H. influenza, Mycoplasma, Chlamydia and others). Opportunistic pathogens take advantage of the state of immunosuppression which is usually highest from one to six months after transplantation. During this period, but also occurring many years later in the setting of a chronically depressed immune system, bacterial pathogens with low intrinsic virulence can cause pneumonia. The diagnosis of pneumonia caused by opportunistic pathogens can be challenging. The delay in diagnosis preventing the early instauration of adequate treatment in kidney transplant recipients with a depressed immune system, frequently coupled with co-morbid conditions and a state of frailty, will affect prognosis and outcome, increasing morbidity and mortality. This review will focus on the most common opportunistic bacterial pathogens causing pneumonia in kidney transplant recipients: Legionella, Nocardia, Mycobacterium tuberculosis/nontuberculous, and Rhodococcus. Recognition of their specificities in the setting of immunosuppression will allow early diagnosis, crucial for initiation of effective therapy and successful outcome. Interactions with immunosuppressive therapy should be considered as well as reducing immunosuppression if necessary.

Fungal pneumonia is a dreaded complication encountered after kidney transplantation, complicated by increased mortality and often associated with graft failure. Diagnosis can be challenging because the clinical presentation is non-specific and diagnostic tools have limited sensitivity and specificity in kidney transplant recipients and must be interpreted in the context of the clinical setting. Management is difficult due to the increased risk of dissemination and severity, multiple comorbidities, drug interactions and reduced immunosuppression which should be applied as an important adjunct to therapy. This review will focus on the main causes of fungal pneumonia in kidney transplant recipients including Pneumocystis, Aspergillus, Cryptococcus, mucormycetes and Histoplasma. Epidemiology, clinical presentation, laboratory and radiographic features, specific characteristics will be discussed with an update on diagnostic procedures and treatment.

Spectral photon-counting CT (SPCCT) is an emerging X-ray imaging technology that extends the scope of available diagnostic imaging tools. The main advantage of photon-counting CT technology is better sampling of the spectral information from the transmitted spectrum in order to benefit from additional physical information being produced during matter interaction, including photo-electric and Compton effects, and the K-edge effect. The K-edge, which is specific for a given element, is the increase in X-ray absorption of the element above the binding energy between its inner electronic shell and the nucleus. Hence, the spectral information contributes to better characterization of tissues and materials of interest, explaining the excitement surrounding this area of X-ray imaging. Other improvements of SPCCT compared with conventional CT, such as higher spatial resolution, lower radiation exposure and lower noise are also expected to provide benefits for diagnostic imaging. In this review, we describe multi-energy CT imaging, from dual energy to photon counting technology, and our initial experience results using a clinical-scale spectral photon counting CT (SPCCT) prototype system in vitro and in vivo. In addition, possible clinical applications are introduced.

In the context of experimental development of vascularized composite tissue allotransplantation (VCA), the auricular model has been described in rats and humans, but not in pigs. A porcine ear transplant, however, represents an interesting experimental composite facial subunit allotransplant because of its reduced morbidity and its translational nature but mostly because it is composed of very different tissues. In this perspective, we studied the anatomical and surgical aspects of an ear subunit VCA in pigs. Our study was performed on 18 pigs: auricular and cervical regions were dissected without preparation (n = 12) or after latex injections (n = 2) in the common carotid artery (CCA). The angiosomes of the caudal auricular artery and superficial temporal artery were studied with selective injections (n = 2). The surgical harvesting protocol was established using the caudal auricular artery as arterial pedicle, and tissue perfusion was studied with injection of Indian ink (n = 1) and angio-CT (n = 1). Finally, two in vivo orthotopic allotransplantations in four pigs were performed, followed by a short observation period. The caudal auricular artery was shown to be the dominant artery to the auricle ensure complete ear perfusion. Venous drainage relied on the caudal and rostral auricular veins, dissected down to the maxillary and external jugular veins. In vivo allotransplantations confirmed proper auricular vascularization on the sole caudal auricular artery under physiological conditions. We have described a new subunit model for experimental face VCA in large animals. Our study reports a reliable harvesting method and easily performed transplantation with a single-based arterial pedicle.

To evaluate how pulmonary artery (PA) distensibility performs in detecting pulmonary hypertension due to left heart disease (PH-LHD) in comparison with parameters from ungated computed tomography (CT) and echocardiography. One hundred patients (79 men, mean age = 63 ± 17 years) with either severe heart failure with reduced ejection fraction (HFrEF), aortic stenosis, or primary mitral regurgitation prospectively underwent right heart catheterization, ungated CT, ECG-gated CT, and echocardiography. During the ECG-gated CT, the right PA distensibility was calculated. In ungated CT, dPA, dPA/AA, the ratio of dPA to the diameter of the vertebra, segmental PA diameter, segmental PA-to-bronchus ratio, and the main PA volume were measured; the egg-and-banana sign was recorded. During echocardiography, the tricuspid regurgitation (TR) gradient was measured. The areas under the ROC curves (AUC) of these signs were computed and compared with DeLong test. Correlation between PA distensibility and PA pressure (PAP) was investigated through Pearson’s coefficient. PA distensibility was lower in patients with PH than in those without PH (11.4 vs. 21.2%, p

Computed tomography (CT) has been the first choice of imaging technique in the emergency department and has a crucial role in many acute conditions. Since its implementation, spectral CT has gained widespread application with the potential to improve diagnostic performance and impact patient care. In spectral CT, images are acquired at two different energy levels allowing this technique to differentiate tissues by exploiting their energy-dependent attenuation properties. Dual-layer spectral CT provides additional information with its material decomposition applications that include virtual non-contrast imaging, iodine density, and effective atomic number (Zeff) maps along with virtual monoenergetic images without the need for preselection of a protocol. This review aims to demonstrate its added value in the emergency department in different organ systems enabling better evaluation of inflammatory and ischaemic conditions, assessment of organ perfusion, tissue/lesion characterisation and mass detection, iodine quantification, and the use of lower volumes of contrast medium. With improved diagnostic performance, spectral CT could also aid in rapid decision-making to determine the treatment method in many acute conditions without increased radiation dose to the patient.

Aim We hypothesized that multiple-choice questions written by radiology residents (MCQresident) for their weekly case presentations during radiology staff meetings could be used along with multiple-choice questions written by radiology teachers (MCQteacher) for their annual evaluation. The current prospective study aimed at determining the educational characteristics of MCQresident and at comparing them with those of MCQteacher. Methods Fifty-one radiology residents of the first to the fifth year of training took the 2017 exam that contained 58 MCQresident and 63 of MCQteacher. The difficulty index, the discrimination power, and the distractor’s quality were calculated in the two series of MCQs and were compared by using Student t test. Two radiologists classified each MCQ according to Bloom’s taxonomy and frequencies of required skills of both MCQ series were compared. Results The mean ± SD difficulty index of MCQresident was statistically significantly higher than that of MCQteacher (0.81 ± 0.1 vs 0.64 ± 0.2; p < 0.0001). The mean ± SD discrimination index of MCQresident was statistically significantly higher than that of MCQteacher (0.34 ± 0.2 vs 0.23 ± 0.2; p = 0.0007). The mean number of non-functional distractors per MCQresident was statistically significantly higher than that per MCQteacher (1.36 ± 0.9 vs 0.86 ± 0.9; p = 0.0031). MCQresident required recalling skills more frequently than MCQteacher which required more advanced skills to obtain a correct answer. Conclusions Educational characteristics of MCQresident differ from those of MCQteacher. This study highlights the characteristics to optimize the writing of MCQs by radiology residents.

Multiphase post-mortem computed tomography (CT) was performed in a 71-year old womanwho died of unknown cause. The corpse was used in the context of forensic expertise withthe goal of optimizing administration of contrast material. CT parameters were as follows:Definition 40®(Siemens Healthineers); beam collimation, 40 × 0.6 mm; tube voltage, 120kVp; tube current, 350 mAs. Vascular opacification was performed using a multiphase post-mortem CT protocol as described elsewhere using 3500 mL of a liposoluble iodine-basedagent (Angiofil®[Fumedica AG], 6% mixed with paraffin oil) [...]

Background COVID-19 pandemic resulted in an unprecedented number of hospitalizations in general wards and intensive care units (ICU). Severe and critical COVID-19 patients suffer from extensive pneumonia; therefore, long-term respiratory sequelae may be expected. Research question We conducted a cohort study to determine respiratory sequelae in patients with severe and critical COVID-19. We aimed at evaluating the proportion of patients with persisting respiratory symptoms and/or abnormalities in pulmonary function tests (PFT) or in lung imaging. Study design and methods: This is a single center cohort study including COVID-19 survivors who underwent a three-month follow-up with clinical evaluation, PFT and lung high-resolution computed tomography (HRCT). All clinical, functional, and radiological data were centrally reviewed. Multiple linear regression analysis was performed to identify factors associated with residual lesions on HRCT. Results Full clinical evaluation, PFT and lung HRCT were available for central review in 126, 122 and 107 patients, respectively. At follow-up, 25% of patients complained from dyspnea and 35% from fatigue, lung diffusion capacity (DLCO) was decreased in 45%, 17% had HRCT abnormalities affecting more than 5% of their lung parenchyma while signs of fibrosis were found in 21%. In multiple linear regression model, number of days in ICU were related to the extent of persisting lesions on HRCT, while intubation was associated with signs of fibrosis at follow-up (P = 0.0005, Fisher's exact test). In contrast, the severity of lung imaging or PFT changes were not predictive of fatigue and dyspnea. Interpretation Although most hospitalized COVID-19 patients recover, a substantial proportion complains from persisting dyspnea and fatigue. Impairment of DLCO and signs suggestive of fibrosis are common but are not strictly related to long-lasting symptoms.

Lung tumor response to therapy may be evaluated in most instances by morphological criteria such as RECIST 1.1 on computed tomography (CT) or magnetic resonance imaging (MRI). However, those criteria are limited because they are based on tumoral dimensional changes and do not take into account other morphologic criteria such as density evaluation, functional or metabolic changes that may occur following conventional or targeted chemotherapy. New techniques such as dual-energy CT, PET-CT, MRI including diffusion-weighted MRI has to be considered into the new technical armamentarium for tumor response evaluation. Integration of all informations provided by the different imaging modalities has to be integrated and represents probably the future goal of tumor response evaluation. The aim of the present paper is to review the current and emerging imaging criteria used to evaluate the response of therapy in the field of lung cancer.

To evaluate the diagnostic performance of brain CT images reconstructed with a model-based iterative algorithm performed at usual and reduced dose. 115 patients with histologically proven lung cancer were prospectively included over 15 months. Patients underwent two CT acquisitions at the initial staging, performed on a 256-slice MDCT, at standard (CTDIvol: 41.4 mGy) and half dose (CTDIvol: 20.7 mGy). Both image datasets were reconstructed with filtered back projection (FBP) and iterative model-based reconstruction (IMR) algorithms. Brain MRI was considered as the reference. Two blinded independent readers analysed the images. Ninety-three patients underwent all examinations. At the standard dose, eight patients presented 17 and 15 lesions on IMR and FBP CT images, respectively. At half-dose, seven patients presented 15 and 13 lesions on IMR and FBP CT images, respectively. The test could not highlight any significant difference between the standard dose IMR and the half-dose FBP techniques (p-value = 0.12). MRI showed 46 metastases on 11 patients. Specificity, negative and positive predictive values were calculated (98.9–100 %, 93.6–94.6 %, 75–100 %, respectively, for all CT techniques). No significant difference could be demonstrated between the two CT reconstruction techniques. • No significant difference between IMR100 and FBP50 was shown. • Compared to FBP, IMR increased the image quality without diagnostic impairment. • A 50 % dose reduction combined with IMR reconstructions could be achieved. • Brain MRI remains the best tool in lung cancer staging.

The cost-effectiveness of clinical interventions is often assessed using current care as comparator. However, evidence suggests practice variation in stroke imaging across countries. For the purpose of feeding into cost-effectiveness analysis, this research aims to describe the patterns of stroke imaging, examine practice variations across countries and, as such, obtain results reflecting current care.A systematic literature review was conducted to identify original studies reporting the imaging workup used in acute stroke care in clinical practice in Hungary, Germany, Sweden and the UK. Information regarding the type and frequency of stroke imaging was analysed. Computed Tomography (CT) was reported as the main diagnostic imaging modality used in stroke care (78-98% across patient profiles and time periods). This review revealed patterns that were not observed in individual studies. Comparisons of UK studies revealed considerable variations in the proportion of scanned patients and timing of imaging.While the evidence about thrombectomy is difficult to translate in clinical practice, the evidence regarding the optimal imaging approach to diagnose stroke patients is lacking. The heterogeneity in stroke imaging reinforces the need to compare the quality of stroke care within and between countries.

OBJECTIVE During the last decade, face allotransplantation has been shown to be a revolutionary reconstructive procedure for severe disfigurements. However, offer to patients remains limited due to lifelong immunosuppression. To move forward in the field, a new pathway in tissue engineering is proposed. BACKGROUND Our previously reported technique of matrix production of a porcine auricular subunit graft has been translated to a human face model. METHODS 5 partial and 1 total face grafts were procured from human fresh cadavers. After arterial cannulation, the specimens were perfused using a combined detergent/polar solvent decellularization protocol. Preservation of vascular patency was assessed by imaging, cell and antigen removal by DNA quantification and histology. The main extracellular matrix proteins and associated cytokines were evaluated. Lip scaffolds were cultivated with dermal, muscle progenitor and endothelial cells, either on discs or in a bioreactor. RESULTS Decellularization was successful in all facial grafts within 12 days revealing acellular scaffolds with full preservation of innate morphology. Imaging demonstrated a preservation of the entire vascular tree patency. Removal of cells and antigens was confirmed by reduction of DNA and antigen markers negativation. Microscopic evaluation revealed preservation of tissue structures as well as of major proteins. Seeded cells were viable and well distributed within all scaffolds. CONCLUSIONS Complex acellular facial scaffolds were obtained, preserving simultaneously a cell-friendly extracellular matrix and a perfusable vascular tree. This step will enable further engineering of postmortem facial grafts, thereby offering new perspectives in composite tissue allotransplantation.

We report the computed tomography (CT) and magnetic resonance imaging (MRI) aspects of a rare case of a patient with a large abdominal hemophilic pseudotumor, a chronic, encapsulated, slowly expanding hematoma occurring in severe hemophilia, without involvement of iliopsoas muscles and iliac bones.

OBJECTIVES: Because of the limited availability of pulmonary homografts (PH), porcine stentless xenografts (SX) have been proposed as an alternative for pulmonary valve replacement in the Ross operation. However, it is unknown whether they have similar good long-term durability. Therefore, we compared mid- to long-term outcomes between those two right ventricular outflow tract (RVOT) substitutes. METHODS: In 288 adults (>18 years) undergoing a Ross operation between 1991 and 2012, Freestyle(®) SX was used in 18 patients and a cryopreserved PH was used in 270 for RVOT reconstruction. Only patients with follow-up >2 years were included. According to the operative period, gender and age, 37 patients with PH could be matched with 17 SX patients. Clinical and echocardiographic follow-up were obtained. In a subset of patients (SX, n = 11 and PH, n = 25), a cardiac computed tomographic (CT) scan was performed to analyse graft calcification. RESULTS: The mean follow-up period was 8.2 ± 4.0 (range 2-14.6 years). During this period, 3 patients died from cancer, 2 in the SX group and 1 in the PH group (P = 0.15). No patient needed RVOT reoperation. At follow-up, RVOT peak gradient was 21 ± 5.9 mmHg in the SX and 16.3 ± 8.7 in the PH groups (P = 0.07). Peak gradient >40 mmHg was observed in only 1 patient in the PH group. Mean RVOT regurgitation was 0.1 ± 0.4 in the SX group and 0.8 ± 0.6 in the PH group (P = 0.008). CT scan analyses showed progressive calcification mainly of the graft wall, while the valve remained relatively free of calcium. Patients with the SX presented significantly higher calcium scores than those with PH (P = 0.01). CONCLUSIONS: In adult patients having the Ross operation, calcic degeneration is observed in both the PH and the SX used as pulmonary substitutes. Calcification progresses more rapidly in the SX compared with the PH. In both grafts, calcifications affect mainly the wall, while the valve remains relatively free of calcium. As a consequence, both grafts show good and similar haemodynamic outcomes at mid- to long-term follow-up. The Freestyle(®) SX can be considered as an acceptable alternative for RVOT reconstruction when PH is not available.

To compare image quality [low contrast (LC) detectability, noise, contrast-to-noise (CNR) and spatial resolution (SR)] of MDCT images reconstructed with an iterative reconstruction (IR) algorithm and a filtered back projection (FBP) algorithm. The experimental study was performed on a 256-slice MDCT. LC detectability, noise, CNR and SR were measured on a Catphan phantom scanned with decreasing doses (48.8 down to 0.7 mGy) and parameters typical of a chest CT examination. Images were reconstructed with FBP and a model-based IR algorithm. Additionally, human chest cadavers were scanned and reconstructed using the same technical parameters. Images were analyzed to illustrate the phantom results. LC detectability and noise were statistically significantly different between the techniques, supporting model-based IR algorithm (p

PURPOSE: The aim of this study was to validate a gradient-based segmentation method for GTV delineation on FDG-PET in NSCLC through surgical specimen, in comparison with threshold-based approaches and CT. MATERIALS AND METHODS: Ten patients with stage I-II NSCLC were prospectively enrolled. Before lobectomy, all patients underwent contrast enhanced CT and gated FDG-PET. Next, the surgical specimen was removed, inflated with gelatin, frozen and sliced. The digitized slices were used to reconstruct the 3D macroscopic specimen. GTVs were manually delineated on the macroscopic specimen and on CT images. GTVs were automatically segmented on PET images using a gradient-based method, a source to background ratio method and fixed threshold values at 40% and 50% of SUV(max). All images were finally registered. Analyses of raw volumes and logarithmic differences between GTVs and GTV(macro) were performed on all patients and on a subgroup excluding the poorly defined tumors. A matching analysis between the different GTVs was also conducted using Dice's similarity index. RESULTS: Considering all patients, both lung and mediastinal windowed CT overestimated the macroscopy, while FDG-PET provided closer values. Among various PET segmentation methods, the gradient-based technique best estimated the true tumor volume. When analysis was restricted to well defined tumors without lung fibrosis or atelectasis, the mediastinal windowed CT accurately assessed the macroscopic specimen. Finally, the matching analysis did not reveal significant difference between the different imaging modalities. CONCLUSIONS: FDG-PET improved the GTV definition in NSCLC including when the primary tumor was surrounded by modifications of the lung parenchyma. In this context, the gradient-based method outperformed the threshold-based ones in terms of accuracy and robustness. In other cases, the conventional mediastinal windowed CT remained appropriate.

OBJECTIVE: The right ventricle is often overlooked on chest and even cardiac MDCT studies. This article will review the normal anatomy of the right ventricle on MDCT and the signs of its functional alterations. CONCLUSION: MDCT signs of right ventricular dysfunction should be known and checked in relevant cases, such as pulmonary embolism in particular, and in any disease that affects both the structure and function of the lungs in general.

The positron emission tomography in combination with CT in hybrid, cross-modality imaging systems (PET/CT) gains more and more importance as a part of the treatment-planning procedure in radiotherapy. Positron emission tomography (PET), as a integral part of nuclear medicine imaging and non-invasive imaging technique, offers the visualization and quantification of pre-selected tracer metabolism. In combination with the structural information from CT, this molecular imaging technique has great potential to support and improve the outcome of the treatment-planning procedure prior to radiotherapy. By the choice of the PET-Tracer, a variety of different metabolic processes can be visualized. First and foremost, this is the glucose metabolism of a tissue as well as for instance hypoxia or cell proliferation. This paper comprises the system characteristics of hybrid PET/CT systems. Acquisition and processing protocols are described in general and modifications to cope with the special needs in radiooncology. This starts with the different position of the patient on a special table top, continues with the use of the same fixation material as used for positioning of the patient in radiooncology while simulation and irradiation and leads to special processing protocols that include the delineation of the volumes that are subject to treatment planning and irradiation (PTV, GTV, CTV, etc.). General CT acquisition and processing parameters as well as the use of contrast enhancement of the CT are described. The possible risks and pitfalls the investigator could face during the hybrid-imaging procedure are explained and listed. The interdisciplinary use of different imaging modalities implies a increase of the volume of data created. These data need to be stored and communicated fast, safe and correct. Therefore, the DICOM-Standard provides objects and classes for this purpose (DICOM RT). Furthermore, the standard DICOM objects and classes for nuclear medicine (NM, PT) and computed tomography (CT) are used to communicate the actual image data created by the modalities. Care must be taken for data security, especially when transferring data across the (network-) borders of different hospitals. Overall, the most important precondition for successful integration of functional imaging in RT treatment planning is the goal orientated as well as close and thorough communication between nuclear medicine and radiotherapy departments on all levels of interaction (personnel, imaging protocols, GTV delineation, and selection of the data transfer method).

The most common presentations of nontuberculous mycobacterial infections in kidney transplant recipients (KTR) are cutaneous and disseminated diseases. Pleuropulmonary infection not associated with disseminated disease is rare. Its diagnosis can be difficult, requiring a combination of clinical, radiological, and bacteriological criteria. We report on a Mycobacterium avium complex pulmonary infection in a KTR with underlying chronic obstructive pulmonary disease. Chest computed tomography showed an excavated lesion of the right upper lobe, similar to a typical lesion of pulmonary tuberculosis. Evolution was favorable with multiple-drug therapy including rifampicin, ethambutol, and clarithromycin, along with a slight reduction in immunosuppression. We review the literature and discuss the epidemiology, diagnosis, management, and follow-up of this uncommon post-transplant complication.

Lung cancer is a major problem in public health and constitutes the leading cause of cancer-related mortality in the world. Lung cancer screening with low-dose computed tomography is promising but needs to overcome many difficulties, such as the large number of incidentally discovered nodules, the radiation dose delivered to the patient during a whole screening program and its cost. The ultimate target point represented by the reduction of lung cancer-related mortality needs to be proved in large, well-designed, randomized, multicenter, prospective trials. Lung cancer staging by morphological tools seems to be limited owing to the presence of metastases in normal-sized lymph nodes. In this context, multidetector computed tomography cannot be used alone but is useful in conjunction with molecular imaging and MRI. Today, flurodeoxglucose PET-CT appears to be the most accurate method for lung cancer staging and may prevent unnecessary thoracotomies. For treatment planning, flurodeoxglucose PET-CT is playing an increasing role in radiotherapy planning at the target selection and definition steps.

Introduction. Bochdalek hernia is a congenital defect of the diaphragm that is usually diagnosed in the neonatal period and incidentally in asymptomatic adults. Small bowel incarceration in a right-sided Bochdalek hernia is exceptional for an adult.Case Presentation. A 54-year-old woman was admitted for acute dyspnea, tachycardia, hypotension, and fever. Five days before, she had been experiencing an episode of diffuse abdominal pain. The admission chest X-ray was interpreted as right pleural effusion and pneumothorax with left mediastinal shift. Chest tube drainage was purulent. The thoracoabdominal CT examination suspected an intestinal incarceration through a right diaphragmatic defect. At laparotomy, a right-sided Bochdalek hernia was confirmed with a complete necrosis of the incarcerated caecum. Ileocaecal resection was performed, but the patient died from delayed septic complications.Conclusion. Intrathoracic perforation of the caecum is a rare occurrence; delayed diagnosis due to misleading initial symptoms may lead to severe complications and poor prognosis.

The last decade has seen a changing pattern of utilization of multidetector CT (MDCT) versus lung perfusion scintigraphy in the investigation of pulmonary venous thromboembolism (VTE). In response to this the International Atomic Energy Agency (IAEA) determined that the subject required an overview. The IAEA has invited a group of five specialists in the relevant fields to review the current status and optimum role of scintigraphy, to explore some of the facts and controversies surrounding the use of both modalities and to make recommendations about the continued role of nuclear medicine for the investigation of pulmonary embolism. This paper identifies the relative merits of each technique, highlights benefits, focuses on complementary roles and seeks a nonadversarial symbiosis. The consultants reached a consensus that the continued use of scintigraphy for diagnosis of thromboembolic disease is recommended, particularly in scenarios where scintigraphy confers specific benefits and is complementary to MDCT.

Although the thrombotic risk of heparin-induced thrombocytopaenia (HIT) is well recognized and may affect any vascular bed, the involvement of adrenal veins has been less commonly described. We report the case of a 86-year-old woman who developed bilateral massive adrenal haematoma associated with HIT, resulting in acute adrenal insufficiency. After immediate discontinuation of heparin and starting therapy with danaparoid and hydrocortisone, the clinical evolution was favourable, although adrenal failure was irreversible. When abdominal pain, hypotension and fever occur during heparin therapy, associated with a drop in platelet count, acute adrenal insufficiency secondary to HIT should be considered, as early diagnosis is essential for the treatment of this life-threatening complication.

Vascular calcification (VC) is prevalent and progressive in renal transplant recipients (RTRs). Recent cross-sectional data suggest that activated Wnt signaling contributes to VC.The objective was to investigate whether circulating levels of the Wnt antagonist sclerostin associate with progression of VC.This was a post hoc analysis of the longitudinal observational Brussels Renal Transplant Cohort study.The setting was a tertiary care academic hospital.Coronary artery calcification and aorta calcification were measured by multislice spiral computerized tomography in 268 prevalent RTRs (age, 53 ± 13 y; 61% male) at baseline and remeasured in 189 patients after a median follow-up of 4.4 years. Baseline serum sclerostin levels were assessed on stored blood samples. Regression analysis was performed to identify determinants of baseline VC and progression.The main outcome measure was progression of VC.VC was present in up to 84% of participants at baseline. Almost half of the patients showed progression of VC, according to Hokanson criteria. The cross-sectional analysis at baseline demonstrated a direct association between sclerostin levels and VC score in univariate analysis, which became inverse after adjustment for age, gender and PTH level. Remarkably, a lower sclerostin level was identified as an independent determinant of a higher baseline aorta calcification score in the final regression model. Moreover, baseline sclerostin levels showed an inverse association with VC progression, at least after adjustment for traditional risk factors.Serum sclerostin levels inversely associated with VC burden and progression in prevalent RTRs after adjustment for traditional risk factors. Our data corroborate previous findings in nontransplanted chronic kidney disease patients and support the notion that sclerostin may be up-regulated in the vascular wall during the VC process as part of a local counterregulatory mechanism directed to suppress VC. Additional clinical and experimental data are required for confirmation.

Background: A 57-year-old patient was admitted for high-grade fever, asthenia, sweating, dry cough and diffuse arthro-myalgias. Two years earlier, elevated titers of anticytoplasmic antibodies (ANCA) of anti-proteinase 3 specificity and renal biopsy led to a diagnosis of granulomatosis with polyangiitis (GPA) with lung and renal involvement. GPA was treated by steroids, cyclophosphamide and rituximab with subsequent clinical and biological remission. The current chest CT scan was performed for a lung opacity that eventually was proved to be an organising pneumonia. CT also showed an unsuspected pattern of the spleen that was compared with a previous chest CT.

OBJECTIVES: The purpose of this research was to compare the diagnostic accuracy of three-dimensional navigator-gated magnetic resonance (MR) imaging and 16-slice multidetector row computed tomography (MDCT) versus quantitative coronary angiography (QCA) for the detection of coronary artery stenosis in patients. BACKGROUND: Both MR and MDCT are novel non-invasive tests, which have been proposed for noninvasive detection of coronary artery disease. Yet their diagnostic accuracy has not been directly compared in the same population. METHODS: Fifty-two patients underwent coronary MR and 16-slice MDCT before invasive coronary angiography. Diameter stenosis (DS) severity in vessels >1.5-mm reference diameter were graded visually and measured quantitatively on both MR and MDCT images. Diagnostic accuracy of both methods was compared using QCA as the reference test. RESULTS: According to QCA, 81 of 452 (18%) coronary segments with >1.5 mm diameter had >50% DS. By visual analysis, MR and MDCT had similar sensitivity (75% vs. 82%, p = NS), specificity (77% vs. 79%, p = NS), and diagnostic accuracy (77%, vs. 80%, p = NS) for detection of >50 % DS. Quantitative measures of DS by MR (r = 0.60, p < 0.001) and MDCT (r = 0.75, both p < 0.001) correlated well with QCA. Receiver-operating characteristic analysis demonstrated that quantification of DS severity improved the diagnostic accuracy of MDCT (area under curve [AUC] 0.81 vs. 0.92, p < 0.001) but not that of MR (AUC 0.78 vs. 0.83, p = NS). CONCLUSIONS: Visual assessment of coronary diameter stenosis severity by MR or MDCT allows identification of significant coronary artery disease with a similar high diagnostic accuracy. Quantitative analysis significantly further improves the diagnostic accuracy of MDCT but not that of MR.

This study aimed to assess the feasibility of cardiac global function evaluation during a whole-chest multi-slice CT (MSCT) acquisition in patients referred for suspicion of pulmonary embolism (PE), and to compare the results with planar equilibrium radionuclide ventriculography (ERNA). Ten consecutive haemodynamically stable patients (six female, four male; mean age 69.7 years; heart rate 65-99 bpm) with suspicion of PE underwent an MSCT and ERNA within a 6 h period. CT acquisition was performed after contrast medium injection by using 16x1.5 mm collimation and retrospective ECG gating. Left ventricular (LVEF) and right ventricular (RVEF) ejection fractions were calculated using dedicated three-dimensional software. Relationships between measurements obtained with MSCT and ERNA were assessed using linear regression analysis and reliability of MSCT was assessed with intra-class correlation coefficient. Bland-Altman analysis was performed to calculate limits of agreement between MSCT and ERNA. MSCT was performed successfully in ten patients with a mean acquisition time of 16.5+/-2.8 s. Functional cardiac evaluation was possible on CT for all patients except for one due to poor opacification of right ventricle. Linear regression analysis showed a good correlation between MSCT and ERNA for the LVEF (R=0.91) and the RVEF (R=0.89) measurements. Intra-class correlation was superior for LVEF (0.92) than for the RVEF (0.68). Bland-Altman plots demonstrated that MSCT substantially overestimated the ERNA RVEF. Morphological CT data demonstrated PE in four of ten of patients and alternative diagnoses in five of ten patients. Our study reveals that MSCT with retrospective ECG gating may provide in one modality a morphological and a functional cardiopulmonary evaluation. Comparison with ERNA demonstrated a good correlation for both ventricular ejection fractions.

PURPOSE: To prospectively compare the diagnostic accuracy of multi-detector row computed tomography (CT) and of three-dimensional (3D) navigator magnetic resonance (MR) imaging in patients referred for conventional coronary angiography for detection of coronary artery stenosis. MATERIALS AND METHODS: All patients gave written informed consent for the study, which was approved by the local ethics committee. Twenty-seven patients underwent multi-detector row CT and 3D navigator free-breathing MR imaging a mean of 5 days before undergoing invasive coronary angiography. The acquired multi-detector row CT and MR images were graded for the presence of greater than 50% stenosis in vessels larger than 1.5 mm in diameter. The diagnostic accuracies of the two examinations were compared with that of quantitative coronary angiography (QCA) by using the McNemar test. RESULTS: Owing to claustrophobia, MR images were not acquired in one patient; thus, 26 patients were included for analysis. According to QCA findings, 21 of the 26 patients had significant coronary artery disease and 58 (20%) of a total of 294 coronary artery segments larger than 1.5 mm in diameter had significant (>50%) stenosis. Multi-detector row CT had significantly higher sensitivity (46 [79%] of 58 segments) than MR imaging (36 [62%] segments, P < .05) for detection of segments with significant stenosis. Conversely, MR imaging had significantly higher specificity (198 [84%] of 236 segments) than did CT (168 [71%] segments, P < .001) for exclusion of segmental coronary artery stenosis. Both examinations had high negative predictive value for exclusion of segmental stenosis: 93% (168 of 180 segments) for CT and 90% (198 of 220 segments) for MR imaging. The overall diagnostic accuracy of MR imaging (80% [234 of 294 segments]) was significantly higher than that of CT (73% [214 segments], P < .05). CONCLUSION: MR imaging had significantly higher diagnostic accuracy than multi-detector row CT in the evaluation of coronary artery stenosis. Both techniques have high negative predictive value, making them particularly useful for ruling out coronary artery disease in symptomatic patients.

PURPOSE: To compare multi-detector row computed tomography (CT) and ventilation-perfusion (V-P) scintigraphy in the diagnosis of acute pulmonary embolism (PE) in outpatients who were cared for in the emergency department. MATERIALS AND METHODS: Ninety-four nonconsecutive patients, in whom acute PE was suspected, underwent thin-collimation multi-detector row CT (collimation, 4 x 1 mm; pitch, 1.25; scanning time, 0.5 second) and V-P scintigraphy. Concordance between CT and scintigraphic images was used in the diagnosis of PE. Pulmonary angiography was performed within 24 hours if interpretations of V-P and spiral CT images were inconclusive or discordant. Sensitivity and specificity values were calculated for V-P scintigrams and CT scans of the lungs. The rates of conclusive results for scintigraphy and CT were compared. RESULTS: The sensitivity of thin-collimation multi-detector row CT and V-P scintigraphy for the detection of PE was 96% (27 of 28; CI: 82%, 99%) and 98% (65 of 66; CI: 92%, 99%), respectively. The specificity of CT and V-P scintigraphy was 86% (24 of 28; CI: 67%, 96%) and 88% (58 of 66; CI: 77%, 94%), respectively. Seven V-P scintigrams were of intermediate probability, and one spiral CT study was indeterminate. Examinations with spiral CT yielded conclusive results more often than examinations with planar V-P scintigraphy (P

Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries.

Objective: To describe CT features associated with severe exacerbations of Chronic Obstructive Pulmonary Disease (COPD).In this prospective ethical-committee-approved study, 44 COPD patients (34 men, 10 women, age range 49-83 years) who provided written informed consent were included at the time of hospital admission for severe exacerbation. Pulmonary function tests (PFT) and chest CT scans were performed at admission and after resolution of the episode following a minimum of 4 weeks free of any acute symptom. For each CT scan, two radiologists independently scored 15 features in each lobe and side. CT features and PFT results were compared for exacerbation and control through Mac-Nemar tests and paired t-tests, respectively.Forced expiratory volume in 1 second and vital capacity improved significantly after exacerbation (p = 0.023 and 0.012, respectively). Bronchial wall thickening and lymphadenopathy were graded significantly higher at exacerbation than at control by both readers (p ranging from0.001 to 0.028). Other CT features were not observed during exacerbation, or were so only by one reader (p ranging from0.001 to 0.928).Only lymphadenopathy and bronchial wall thickening are CT features associated with severe COPD exacerbation, respectively in 25% and 50% of patients. Our findings do not advocate a role for CT in the routine work-up of patients with severe COPD exacerbation.

Background: A 42-year-old male presented with dyspnea following a syncopal episode a few hours before admission. He had completed his military service 2 months previously. Electrocardiogram showed a complete heart branch block with severe bradycardia measured at 30 bpm. Imaging included chest radiography, CT scan of the chest, heart and abdomen and MRI of the heart.

A 19-year-old man was admitted with acute dyspnoea. Physical examination revealed subcutaneous emphysema in the cervical and thoracic area. This was further confirmed by the total body computed tomography that also demonstrated mediastinal emphysema. Epidural pneumatosis of the thoracis spine was also evident. There was no history of trauma, but well of a recent oral ecstasy consumption during a techno rave party, associated with intense dancing and jumping. Clinical course was favourable with conservative therapy.

Purpose Cardiac perforations due to pacing and implantable defibrillator lead displacement are rare and their detection may be difficult. The goal of this study was to review the clinical and imaging presentation of cardiac perforation related to pacing lead displacement. Patients and methods The clinical and imaging files of four patients (two men and two women) who experienced cardiac perforation related to pacing lead displacement were reviewed. The four patients were investigated in our radiology department over a 24-month-period. Results Two patients had clinical symptoms at the time lead displacement was detected and the other two were free of symptoms. In all patients, lead displacement was visible on imaging examinations in retrospect but was not detected prospectively. Conclusion Radiologists should pay attention to the position of the tips of the leads on chest X-ray and CT, even late after the implantation and in asymptomatic patients.