High resolution propagation-based lung imaging at clinically relevant X-ray dose levels.

Absorption-based clinical computed tomography (CT) is the current imaging method of choice in the diagnosis of lung diseases. Many pulmonary diseases are affecting microscopic structures of the lung, such as terminal bronchi, alveolar spaces, sublobular blood vessels or the pulmonary interstitial tissue. As spatial resolution in CT is limited by the clinically acceptable applied X-ray dose, a comprehensive diagnosis of conditions such as interstitial lung disease, idiopathic pulmonary fibrosis or the characterization of small pulmonary nodules is limited and may require additional validation by invasive lung biopsies. Propagation-based imaging (PBI) is a phase sensitive X-ray imaging technique capable of reaching high spatial resolutions at relatively low applied radiation dose levels. In this publication, we present technical refinements of PBI for the characterization of different artificial lung pathologies, mimicking clinically relevant patterns in ventilated fresh porcine lungs in a human-scale chest phantom. The combination of a very large propagation distance of 10.7 m and a photon counting detector with [Formula: see text] pixel size enabled high resolution PBI CT with significantly improved dose efficiency, measured by thermoluminescence detectors. Image quality was directly compared with state-of-the-art clinical CT. PBI with increased propagation distance was found to provide improved image quality at the same or even lower X-ray dose levels than clinical CT. By combining PBI with iodine k-edge subtraction imaging we further demonstrate that, the high quality of the calculated iodine concentration maps might be a potential tool for the analysis of lung perfusion in great detail. Our results indicate PBI to be of great value for accurate diagnosis of lung disease in patients as it allows to depict pathological lesions non-invasively at high resolution in 3D. This will especially benefit patients at high risk of complications from invasive lung biopsies such as in the setting of suspected idiopathic pulmonary fibrosis (IPF).

Increased Inflammatory Markers Detected in Nasal Lavage Correlate with Paranasal Sinus Abnormalities at MRI in Adolescent Patients with Cystic Fibrosis.

Chronic rhinosinusitis (CRS) is a characteristic feature of cystic fibrosis (CF) multiorgan disease and develops early in the life of patients with CF. The study aimed to correlate the inflammatory markers and the presence of structural abnormalities detected by MRI in the paranasal sinuses of patients with CF. Methods: Nasal lavage and MRI of the paranasal sinuses was performed in a cohort of 30 CF patients (median age 14 y; range 7-20 y). Morphological abnormalities characteristic of CF were evaluated with a dedicated CRS MRI scoring system and correlated with different inflammation parameters measured in nasal lavage. Inflammation of the paranasal sinuses was positively associated with structural abnormalities in MRI. The concentration of the pro-inflammatory markers neutrophil elastase (NE) and the neutrophil elastase/alpha1-antitrypsin (NE/A1AT) complex correlated significantly with CRS-MRI sum score (p < 0.05, r = 0.416 and p < 0.05, r = 0.366, respectively). S. aureus infection was associated with the increased pro-inflammatory cytokine activity of IL-6 and IL-8, and increased levels of NE/A1AT complex in our patients (p < 0.05, respectively). CRS-MRI sum score and individual sinus MRI scores were positively associated with inflammatory activity as a sign of CRS pathology present in CF.

Mesopolysaccharides: The extracellular surface layer of visceral organs.

The mesothelium is a dynamic and specialized tissue layer that covers the somatic cavities (pleural, peritoneal, and pericardial) as well as the surface of the visceral organs such as the lung, heart, liver, bowel and tunica vaginalis testis. The potential therapeutic manipulation of visceral organs has been complicated by the carbohydrate surface layer-here, called the mesopolysaccharide (MPS)-that coats the outer layer of the mesothelium. The traditional understanding of MPS structure has relied upon fixation techniques known to degrade carbohydrates. The recent development of carbohydrate-preserving fixation for high resolution imaging techniques has provided an opportunity to re-examine the structure of both the MPS and the visceral mesothelium. In this report, we used high pressure freezing (HPF) as well as serial section transmission electron microscopy to redefine the structure of the MPS expressed on the murine lung, heart and liver surface. Tissue preserved by HPF and examined by transmission electron microscopy demonstrated a pleural MPS layer 13.01±1.1 um deep-a 100-fold increase in depth compared to previously reported data obtained with conventional fixation techniques. At the base of the MPS were microvilli 1.1±0.35 um long and 42±5 nm in diameter. Morphological evidence suggested that the MPS was anchored to the mesothelium by microvilli. In addition, membrane pits 97±17 nm in diameter were observed in the apical mesothelial membrane. The spatial proximity and surface density (29±4.5%) of the pits suggested an active process linked to the structural maintenance of the MPS. The striking magnitude and complex structure of the MPS indicates that it is an important consideration in studies of the visceral mesothelium.

Impact of MRI, CT, and Clinical Characteristics on Microbial Pathogen Detection Using CT-Guided Biopsy for Suspected Spondylodiscitis.

Spondylodiscitis accounts for 2-7% of osteomyelitis cases and is characterized by pain, systemic inflammation, and permanent neurological deficits. We aimed to identify imaging characteristics and clinical parameters to successfully predict microbiological pathogens by computed tomography (CT)-guided biopsy in suspected spondylodiscitis cases. Forty consecutive patients (mean age 65.1 years) with suspected spondylodiscitis underwent CT-guided biopsy. CT features (non-sclerotic endplate erosions (NSEs)), magnetic resonance criteria (paravertebral/epidural abscess (PA/EA) formation), and clinical data (C-reactive protein (CRP) > 50 mg/L) were assessed for their predictive potential. NSEs were detected in 6/11 (54.5%) and 1/29(3.4%) patients with positive and negative microbiology, respectively. PA and EA, respectively, were present in 7/11(63.6%) and 3/11 patients with positive microbiology and 7/29 (24.1%) and 2/29 patients with negative microbiology. CRP > 50 was observed in 7/11 (63.6%) and in 7/29 (24.1%) patients with positive and negative microbiology, respectively. Three double combinations possessed near-perfect specificity (PA + NSE, 100%; PA + CRP > 50, 96.6%; NSE + CRP > 50, 96.6%). The top three Youden indices included combinations with NSE. Since CT/magnetic resonance (MR) imaging and CRP are routinely used to evaluate spondylodiscitis, the presented diagnostic criteria and combinations can aid decision-making for biopsy.

Modern Cartilage Imaging of the Ankle.

Background Talar osteochondral lesions are an important risk factor for the development of talar osteoarthritis. Furthermore, osteochondral lesions might explain persistent ankle pain. Early diagnosis of accompanying chondral defects is important to establish the optimal therapy strategy and thereby delaying or preventing the onset of osteoarthritis. The purpose of this review is to explain modern cartilage imaging with emphasis of MR imaging as well as the discussion of more sophisticated imaging studies like CT-arthrography or functional MR imaging. Methods Pubmed literature search concerning: osteochondral lesions, cartilage damage, ankle joint, talus, 2 D MR imaging, 3 D MR imaging, cartilage MR imaging, CT-arthrography, cartilage repair, microfracture, OATS, MACT. Results and Conclusion Dedicated MR imaging protocols to delineate talar cartilage and the appearance of acute and chronic osteochondral lesions were discussed. Recent developments of MR imaging, such as isotropic 3 D imaging that has a higher signal-to noise ratio when compared to 2 D imaging, and specialized imaging methods such as CT-arthrography as well as functional MR imaging were introduced. Several classifications schemes and imaging findings of osteochondral lesions that influence the conservative or surgical therapy strategy were discussed. MRI enables after surgery the non-invasive assessment of the repair tissue and the success of implantation. Key points · Modern MRI allows for highly resolved visualization of the articular cartilage of the ankle joint and of subchondral pathologies.. · Recent advances in MRI include 3 D isotropic ankle joint imaging, which deliver higher signal-to-noise ratios of the cartilage and less partial volume artifacts when compared with standard 2 D sequences.. · In case of osteochondral lesions MRI is beneficial for assessing the stability of the osteochondral fragment and for this discontinuity of the cartilage layer is an important factor.. · CT-arthrography can be used in case of contraindications of MRI and in unclear MRI findings as further diagnostic approach.. Citation Format · Weber MA, Wünnemann F, Jungmann PM et al. Modern Cartilage Imaging of the Ankle. Fortschr Röntgenstr 2017; 189: 945 - 956.