[show abstract][hide abstract] ABSTRACT: A recent paradigm shift in radiology has focused on the globalization of so-called P4 radiology. P4 radiology represents delivery of imaging results that are predictive, personalized, pre-emptive and participatory. The combination of the P4 approach and biomarkers is particularly pertinent to MRI, especially with technological advances such as diffusion-weighted imaging. The development of new liver-specific MRI contrast media, particularly gadoxetic acid, demonstrate specific pharmacokinetic properties, which provide combined morphologic and functional information in the same setting. The evaluation of hepatobiliary pathology beyond morphology gives rise to the possibilty of using gadoxetic acid-enhanced MRI as an imaging biomarker of hepatobiliary diseases. The integration of functional imaging with an understanding of complex disease mechanisms forms the basis for P4 radiology, which may ultimately lead to individualized, cost-effective, targeted therapy for patients. This will enable radiologists to determine the prognosis of the disease and estimate early response to treatment, with the participation of all the required medical disciplines.
Expert review of gastroenterology & hepatology 02/2014; 8(2):147-60.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE. The purpose of this study was to use second-generation dual-source CT to assess the influence of size, degree of stenosis, luminal contrast attenuation, and plaque geometry on stenosis quantification in a coronary artery phantom. MATERIALS AND METHODS. Six vessel phantoms with three outer diameters (2, 3, and 4 mm), each containing three radiolucent plaques (72.2 HU) that simulated eccentric and concentric 43.8%, 75%, and 93.8% stenoses were made with a 3D printer system. These phantoms were filled with an iodine-saline solution mixture at luminal attenuations of 150, 200, 250, 300, and 350 HU and were attached to a cardiac motion simulator. Dual-source CT was performed with a standardized ECG-gated protocol (120 kV, 360 mAs per rotation) at a simulated heart rate of 70 beats/min. Two independent readers quantified the degree of stenosis using area-based measurements. RESULTS. All measurements were highly reproducible (intraclass correlation, ≥ 0.791; p < 0.001). The mean measured degree of stenosis for a phantom with a 3-mm outer diameter at 250-HU luminal attenuation was 49.0% ± 10.0% for 43.8% stenosis, 71.7% ± 9.6% for 75.0% stenosis, and 85.4% ± 5.9% for 93.8% stenosis. With decreasing phantom size, measurement error increased for all degrees of stenosis. The absolute error increased for measurements at a low luminal attenuation of 150 HU (p < 0.001) and for low-grade stenoses compared with medium-and high-grade stenoses (p < 0.001). CONCLUSION. The results are an overview of factors that influence stenosis quantification in simulated coronary arteries. Dual-source CT is highly reproducible and accurate for quantification of low-density stenosis in vessels with a diameter of 3 mm and attenuation of at least 200 HU for different degrees of stenosis and plaque geometry.
American Journal of Roentgenology 08/2013; 201(2):W227-34. · 2.90 Impact Factor
[show abstract][hide abstract] ABSTRACT: Oncologic imaging includes the morphological description of the primary tumor region for an accurate classification of the tumor and lymph node stage and whether distant metastases have occurred according to the TNM staging system. Knowing the stage of the disease helps to plan the treatment and to estimate the prognosis. In clinical routine this is accomplished by conventional imaging techniques, such as ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI). Additionally, oncologic imaging is essential in treatment monitoring to visualize and quantify the effect of cancer therapy according to response evaluation criteria in solid tumors (RECIST) and World Health Organization (WHO) criteria. The tremendous development in oncology and technical innovations in imaging represent a particular challenge for radiology.
[show abstract][hide abstract] ABSTRACT: Abstract Objectives: To evaluate the fetal magnetic resonance imaging findings of lymphangiomas. Methods: The magnetic resonance scans of eight fetuses with lymphangiomas were evaluated. Magnetic resonance evaluation included: number; size; signal intensities of the lesions; thickness of the septae; configuration of the margins; presence of blood breakdown products; change in size or signal intensity (in four patients with multiple examinations); exact expansion of the lesions to the adjacent anatomical structures; and concomitant pathological findings. Results were compared with postpartum clinical assessment and imaging in seven patients and with autopsy in one patient. Results: Two retroperitoneal, three thoracic, and three cervical lymphangiomas (diameters between 3.3 and 15.6 cm) were included. All lesions consisted of macrocysts, and additional microcystic parts were found in three lymphangiomas. Blood breakdown products were found in one lesion. Agreement with postpartum imaging was excellent. One patient received intrauterine drainage for chylothorax, and one pregnancy was terminated. Conclusions: Fetal lymphangiomas display the same magnetic resonance imaging features as postnatal lymphangiomas. Intrauterine magnetic resonance characterization of lymphangiomas provides the exact delineation, detection of associated and/or concomitant pathologies, and differential diagnosis among other cystic pathologies. Patient management may be altered with respect to the type and/or time of treatment, and with regard to the continuation or termination of pregnancy.
Journal of Perinatal Medicine 01/2013; · 1.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: PURPOSE: The aim of this study was to survey the current CT protocols used by members of the European Society of Thoracic Imaging (ESTI) to evaluate patients with interstitial lung diseases (ILD). METHODS: A questionnaire was e-mailed to 173 ESTI members. The survey focussed on CT acquisition and reconstruction techniques. In particular, questions referred to the use of discontinuous HRCT or volume CT protocols, the acquisition of additional acquisitions in expiration or in the prone position, and methods of radiation dose reduction and on reconstruction algorithms. RESULTS: The overall response rate was 37 %. Eighty-five percent of the respondents used either volume CT alone or in combination with discontinuous HRCT. Forty-five percent of the respondents adapt their CT protocols to the patient's weight and/or age. Expiratory CT or CT in the prone position was performed by 58 % and 59 % of the respondents, respectively. The number of reconstructed series ranged from two to eight. CONCLUSION: Our survey showed that radiologists with a special interest and experience in chest radiology use a variety of CT protocols for the evaluation of ILD. There is a clear preference for volumetric scans and a strong tendency to use the 3D information. KEY POINTS: • Experienced thoracic radiologists use various CT protocols for evaluating interstitial lung diseases. • Most workers prefer volumetric CT acquisitions, making use of the 3D information • More attention to reducing the radiation dose appears to be needed.
[show abstract][hide abstract] ABSTRACT: To determine, in patients with melanoma, the dependence of PET sensitivity on pulmonary metastasis size, and to determine patients who require further evaluation for definite staging.
Of 183 melanoma patients who underwent (18)F-fluorodeoxyglucose PET/computed tomography (CT) for staging or follow-up between January 2008 and June 2011, 38 patients (18 women and 20 men; mean age 62.0 ± 14.7 years) with one or more pulmonary metastases visible on CT were included in the retrospective study. Each pulmonary metastasis was rated as positive or negative on PET, and lesion size (maximum transverse diameter) was assessed on CT. PET sensitivity was calculated according to the lesions' size, in 2-mm steps.
A total of 181 pulmonary metastases were analysed. PET sensitivity was 7.9 % for lesions of 4-5 mm; 33.3 % for lesions of 6-7 mm; 56.8 % for lesions of 8-9 mm; 63.6 % for lesions of 10-11 mm; 100 % for lesions of 12-14 mm; and 100 % for lesions of at least 15 mm. The differences in sensitivity between the size groups were significant (P < 0.001)
With current state-of-the-art PET/CT technology, additional tests are necessary for definitive staging of melanoma patients who have one or more PET-negative lung nodules less than 12 mm in diameter on expiratory CT. KEY POINTS : • PET cannot rule out malignancy in pulmonary nodules less than 12 mm on expiratory CT. • Melanoma patients with PET-negative pulmonary nodules less than 12 mm require additional tests. • Knowledge of these factors can help interpretation of PET and PET/CT findings.
European Radiology 06/2012; 22(11):2451-7. · 3.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC).
Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0-1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n=43) or a venous phase, were retrospectively analyzed. Mean attenuation was measured within regions of interest of the phantoms and in different tissue types of the patients within the corresponding VNC and TNC images. Paired t-tests and Pearson correlation were used for statistical analysis.
For all phantoms, mean attenuation in VNC was 5.3±18.4 HU, with respect to water. In 86 patients overall, 2637 regions were measured in TNC and VNC images, with a mean difference between TNC and VNC of -3.6±8.3 HU. In 91.5% (n=2412) of all cases, absolute differences between TNC and VNC were under 15HU, and, in 75.3% (n=1986), differences were under 10 HU.
Second-generation dual-energy CT based VNC images provide attenuation values close to those of TNC. To avoid possible outliers multiple measurements are recommended especially for measurements in the spleen, the mesenteric fat, and the aorta.
European journal of radiology 03/2012; 81(3):e398-405. · 2.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Purpose: To evaluate the stand-alone performance of a computer-aided detection (CAD) algorithm for colorectal polyps in a large heterogeneous CT colonography (CTC) database that included both tagged and untagged datasets.
Methods: Written, informed consent was waived for this institutional review board-approved, HIPAA-compliant retrospective study. CTC datasets from 2063 patients were assigned to training (n = 374) and testing (n = 1689). The test set consisted of 836 untagged and 853 tagged examinations not used for CAD training. Examinations were performed at 15 sites in the United States, Asia, and Europe, using 4- to 64-multidetector-row computed tomography and various acquisition parameters. CAD sensitivities were calculated on a per-patient and per-polyp basis for polyps measuring ≥6 mm. The reference standard was colonoscopy in 1588 (94%) and consensus interpretation by expert radiologists in 101 (6%) patients. Statistical testing employed χ2, logistic regression, and Mann-Whitney U tests.
Results: In 383 of 1689 individuals, 564 polyps measuring ≥6 mm were identified by the reference standard (347 polyps: 6–9 mm and 217 polyps: ≥10 mm). Overall, CAD per-patient sensitivity was 89.6% (343/383), with 89.0% (187/210) for untagged and 90.2% (156/173) for tagged datasets (P = 0.72). Overall, per-polyp sensitivity was 86.9% (490/564), with 84.4% (270/320) for untagged and 90.2% (220/244) for tagged examinations (P = 068). The mean false-positive rate per patient was 5.14 (median, 4) in untagged and 4.67 (median, 4) in tagged patient datasets (P = 0.353).
Conclusion: Stand-alone CAD can be applied to both tagged and untagged CTC studies without significant performance differences. Detection rates are comparable to human readers at a relatively low false-positive rate, making CAD a useful tool in clinical practice.
[show abstract][hide abstract] ABSTRACT: To evaluate the accuracy of multidetector computed tomography with water filling (Hydro-MDCT) in the T-staging of patients with oesophageal cancer.
There were 131 consecutive patients who were preoperatively and prospectively examined in the prone position on arterial phase contrast-enhanced MDCT, after ingestion of 1,000-1,500 ml tap water and effervescent granules. Two readers staged the local tumour growth (T-staging) independently. They assessed tumour location, size, presence of stenosis, and morphology of the outer border of the oesophageal wall and perioesophageal fat planes on CT. CT findings were compared with histopathological results from resected specimens. Data were analyzed using the SPSS statistical package.
Both readers obtained a high sensitivity of 95% and a high positive predictive value of 96%. Accurate local staging was achieved in 76.3% and 68.7% for readers 1 and 2, respectively. Inter-reader agreement was excellent (weighted κ value of 0.93 and un-weighted κ of 0.89).
Using the hydro-technique and applying specific assessment criteria, MDCT appears to be an accurate, non-invasive diagnostic tool for local tumour staging of oesophageal cancer.
European Radiology 06/2011; 21(11):2326-35. · 3.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: A 33-year-old male patient was admitted to our nephrology department with rapidly deteriorating general health, fever, respiratory difficulties, and acute renal failure. Computed tomography of the thorax revealed interstitial edema with thickening of the interlobular septa, peribronchial cuffing, ground-glass opacities, and small pleural and pericardial effusions. Polymerase chain reaction tests verified Puumala virus infection. The patient recovered with supportive treatment. Hantavirus infection should be considered in the differential diagnosis of young patients who present with acute renal failure of an unknown origin and the nonspecific radiologic finding of noncardiogenic interstitial edema, which in combination with typical clinical symptoms and laboratory parameters, can be indicative of this disease.
Journal of thoracic imaging 05/2011; 26(2):W51-3. · 1.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: Non-traumatic chest pain is a common symptom in patients who present in the emergency department. From a clinical point of view, it is important to differentiate cardiac chest pain from non-cardiac chest pain (NCCP). Among the plethora of potential causes of NCCP, life-threatening diseases, such as aortic dissection, pulmonary embolism, tension pneumothorax, and esophageal rupture, must be differentiated from non-life threatening causes. The majority of NCCP, however, is reported to be benign in nature. The presentation of pain plays an important role in narrowing the differential diagnosis and initiating further diagnostic management and treatment. As the benign causes tend to recur, and may lead to patient anxiety and great costs, a meticulous evaluation of the patient is necessary to diagnose the underlying disorder or disease.
European journal of radiology 04/2011; · 2.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pneumonia is one of the most frequent causes of morbidity and mortality throughout the world. It is the most prevalent community-acquired
infection and the second most common nosocomial infectious disorder. Infections may occur in healthy people or individuals
with concomitant intrapulmonary or extrathoracic diseases. Pneumonia may develop into a life-threatening condition, especially
in immunocompromised patients, in children, and in the elderly.
[show abstract][hide abstract] ABSTRACT: To retrospectively assess the rate of detection of skull fractures at cranial computed tomography (CT) achieved with the use of curved maximum intensity projections (MIPs) compared with that achieved by reading transverse sections only.
The institutional review board approved this research and waived informed consent. A curved thin (3-mm) MIP of the skull cap and a curved thick (50-mm) MIP of the skull base were obtained from the cranial CT data in 200 consecutive patients with head trauma. Four radiologists (two residents without experience in cranial CT and two consultants) independently evaluated all cases. Each radiologist reported findings in 100 patients by using transverse sections only and findings in the other 100 patients by using the unfolded view. The radiologists were blinded to patient names, and patient and group orders were randomized. The results were compared with a standard of reference established by two experts from all prior reading results, all reconstructions, and high-spatial-resolution multiplanar reformats. Logistic regression with repeated measurements was used for statistical analysis.
The experts found 63 fractures in 30 patients. When transverse sections only were used, the mean patient-based fracture detection rate was 43% (13 of 30) for inexperienced and 70% (21 of 30) for experienced readers; with curved MIPs, the rates were 80% (24 of 30) and 87% (26 of 30), respectively. Overall sensitivity was higher with curved MIPs (P < .001); specificity was higher with transverse sections (P < .001).
Curved MIPs enable a significantly higher fracture detection rate than transverse sections. They also considerably close the experience gap in fracture detection rate between residents and experts.