Influence of leg axis alignment on MRI T2* mapping of the knee in young professional soccer players.

BACKGROUND: Investigation of the association between leg axis alignment and biochemical MRI in young professional soccer players in order to identify a potential influence of the leg axis on cartilage regions at risk. METHODS: Sixteen professional soccer players (21 ± 3 years) underwent static and dynamic leg axis analysis via radiation free DIERS formetric 4 D as well as 3-T MRI examination of both knees. Quantitative T2* mapping of the knee cartilage was performed and T2* values were evaluated as 144 regions of interest. Subgroup analysis was performed in players with severe varus alignment (> 6°). RESULTS: Analysis of the leg axis geometry revealed a mean static alignment of 6.6° ± 2.5 varus and a mean dynamic alignment of 5.1° ± 2.6 varus. Quantitative T2* mapping showed significantly increased T2* values in the superficial cartilage layer compared to the deeper region (p < 0.001) as well as a significant increase in relaxation times in the femoral cartilage from anterior to intermediate to posterior (p < 0.001). Combination of both methods revealed a significant correlation for the degree of varus alignment and the femoral, posterior, deep region of the medial knee compartment (r = 0.4; p = 0.03). If severe varus alignment was present this region showed a significant increase in relaxation time compared to players with a less pronounced leg axis deviation (p = 0.003). CONCLUSION: This study demonstrates that varus alignment in young soccer players is associated with elevated T2* relaxation times in the deep cartilage layer of the medial, posterior, femoral compartment and might therefore be a contributing factor in the early pathogenesis of manifest cartilage lesions. Therefore, these findings should be considered in the development of preventive training programs.

Comparison of meniscal T1rho- and T2*-relaxation times in professional female volleyball players and healthy controls using 3T MRI: A pilot study.

PURPOSE: Comparison of meniscal T1rho- and T2*-relaxation times in professional female volleyball players and healthy controls to determine if relaxation times are prolonged in athletes due to compositional meniscal alterations based on extensive and repetitive joint loading. METHODS: The right knee of 20 asymptomatic professional female volleyball players and 20 female controls were examined at 3T MRI. T1rho- and T2*-measurements were performed in sagittal orientation. For quantitative measurements, two readers independently defined two consecutive central slices with the greatest area of the anterior and posterior horn of the lateral (AHLAT; PHLAT) and medial meniscus (AHMED; PHMED). Both readers repeated measurements after a six-week interval on the original MR images. Statistical analysis included intraclass correlation coefficient (ICC), Wilcoxon signed-rank-, Shapiro-Wilk- & Kolmogorov-Smirnov- and Mann-Whitney U-tests. RESULTS: Mean T1rho-relaxation times in the PHMED were significantly prolonged in professional female volleyball players when compared to controls (24.2 ± 4.0 vs 21.1 ± 2.6 ms; p < 0.005). There were no significant differences for the remaining three meniscal horns. T2*-relaxation times revealed no significant differences between athletes and controls. Prolonged T1rho-relaxation times in the PHMED of female volleyball players did not correlate with significant change in T2*-relaxation times within all meniscal subregions. Reproducibility levels were excellent in all segments (Interobserver-ICC: 0.93-0.97 and intraobserver-ICC: 0.97-0.99). CONCLUSION: T1rho-relaxation times were significantly increased in the PHMED of female volleyball players, potentially indicating a predilection to early degenerative meniscal changes. T1rho may serve as a sensitive biomarker at detecting early compositional meniscal alterations in athletes.

Correlation of T2* relaxation times of the retropatellar cartilage with tibial tuberosity-trochlea groove distance in professional soccer players.

The tibial tuberosity-trochlear groove (TT-TG) distance is a radiographic measurement that is used to quantify malalignment of the patellofemoral joint (PFJ) in cross-sectional imaging. There is an ongoing debate about the impact of the TT-TG-distance on lateral patellar instability and the initiating of cartilage degeneration. In this prospective study, the association of T2* relaxation times and TT-TG distances in professional soccer players was analyzed. 36 knees of 18 professional soccer players (age: 21 ± 2.8 years) were evaluated. Participants underwent knee MRI at 3 T. For qualitative image analysis, fat-saturated 2D PD-weighted Fast Spin Echo (FSE) and T1-weighted FSE sequences were used. For quantitative analysis, T2* measurements in 3D data acquisitions were performed. In a qualitative analysis there was no structural cartilage damage and no abnormalities of the patellar and trochlea shape. The highest T2* values (26.7 ± 5.9 ms) were observed in the central compartment of the patella. The mean TT-TG distance was 10 ± 4 mm (range 3-20 mm). There was no significant correlation between TT-TG distance and T2* relaxation times in all three compartments of the retropatellar cartilage. Our study shows that so long as patellar and trochlear morphology is normal, TT-TG distance alone does not affect the tissue structure of the retropatellar cartilage in professional soccer players.

Comparison of T2* relaxation times of articular cartilage of the knee in elite professional football players and age-and BMI-matched amateur athletes.

OBJECTIVE: Recent investigation has underlined the potential of quantitative MR imaging to be used as a complementary tool for the diagnosis of cartilage degeneration at an early state. The presented study analyses T2* relaxation times of articular cartilage of the knee in professional athletes and compares the results to age- and BMI (Body Mass Index)-matched healthy amateur athletes. MATERIALS AND METHODS: 22 professional football players and 22 age- and BMI-matched individuals were underwent knee Magnetic Resonance Imaging (MRI) at 3T including qualitative and quantitative analysis. Qualitative analysis included e.g. meniscal tears, joint effusion and bone edema. For quantitative analysis T2* (22 ET: 4.6-53.6ms) measurements in 3D data acquisition were performed. Deep and superficial layers of 22 predefined cartilage segments were analysed. All data sets were postprocessed using a dedicated software tool. Statistical analysis included Student t-test, confidence intervals and a random effects model. RESULTS: In both groups, T2* relaxation times were significantly higher in the superficial compared to the deep layers (p<0.001). Professional athletes had significantly higher relaxation times in eight superficial and three deep cartilage layers in the predefined cartilage segments (p<0.05). Highly significant differences were found in the weight-bearing segments of the lateral superficial femoral condyle (p<0.001). CONCLUSION: Elevated T2* values in cartilage layers of professional football players compared to amateur athletes were noted. The effects seem to predominate in superficial cartilage layers.

Performance of cone-beam computed tomography and multidetector computed tomography in diagnostic imaging of the midface: A comparative study on Phantom and cadaver head scans.

PURPOSE: To compare multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) regarding radiation, resolution, image noise, and image quality. METHODS: CBCT and 256-MDCT were compared based on three scan protocols: Standard-dose (≈24 mGy), reduced-dose (≈9 mGy), and low-dose (≈4 mGy). MDCT images were acquired in standard- and high-resolution mode (HR-MDCT) and reconstructed using filtered back projection (FBP) and iterative reconstruction (IR). Spatial resolution in linepairs (lp) and objective image noise (OIN) were assessed using dedicated phantoms. Image quality was assessed in scans of 25 cadaver heads using a Likert scale. RESULTS: OIN was markedly higher in FBP-MDCT when compared to CBCT. IR lowered the OIN to comparable values in standard-mode MDCT only. CBCT provided a resolution of 13 lp/cm at standard-dose and 11 lp/cm at reduced-dose vs. 11 lp/cm and 10 lp/cm in HR-MDCT. Resolution of 10 lp/cm was observed for both devices using low-dose settings. Quality scores of MDCT and CBCT did not differ at standard-dose (CBCT, 3.4; MDCT, 3.3-3.5; p > 0.05). Using reduced- and low-dose protocols, CBCT was superior (reduced-dose, 3.2 vs. 2.8; low dose, 3.0 vs. 2.3; p < 0.001). CONCLUSION: Using the low-dose protocol, the assessed CBCT provided better objective and subjective image quality and equality in resolution. Similar image quality, but better resolution using CBCT was observed at higher exposure settings. KEY POINTS: • The assessed CBCT device provided better image quality at lower doses. • Objective and subjective image quality were comparable using higher exposure settings. • CBCT showed superior spatial resolution in standard-dose and reduced-dose settings. • Modern noise-reducing tools are used in CBCT devices currently. • MDCT should be preferred for assessment of soft-tissue injuries and oncologic imaging.

Thoracic Pathologies on Scout Views and Bolus Tracking Slices for Computed Tomographic Cerebral Angiography.

PURPOSE: To evaluate the incidence of additional thoracic pathologic findings (TPF) detected on scout views and corresponding bolus tracking slices (SVBT) for computed tomographic cerebral angiography (CTCA) and to test the reliability and accuracy of these findings. MATERIALS AND METHODS: The study collective included 505 consecutive patients who underwent multidetector CTCA. Appendant SVBT of all patients were reviewed for any pathologic findings and patient medical reports were analyzed, if any medical treatment was initiated for the detected pathologic findings. In 18 patients thoracic CT scans were performed in the same session. These were additionally reviewed by two blinded observers to test for intra- and interobserver reliability as well as for accuracy of detecting thoracic pathologies on SVBT. RESULTS: TPF were detected in 165 (33%) SVBT. The five most common pathologic findings were: pleural effusion, 12%; pneumonia, 8%; atelectasis/dystelecatsis, 6%; pericardial effusion, 2% and elevated diaphragm, 1%. For 48 % of these findings medical treatment was initiated. SVBT showed a sensitivity of 53%, a specificity of 99%, a positive predictive value of 89%, a negative predictive value of 94% and accuracy of 94% for the detection of TPF. The intraobserver reliability was very good and the interobserver reliability showed moderate agreement. CONCLUSION: SVBT for CTCA should be reviewed with care by radiologists, since additional TPF can affect patient management. Nevertheless, despite a high specificity of SVBT for detecting TPF, an only moderate sensitivity has to be taken into account. KEY POINTS: Thoracic pathologies are frequently found on scout views for cerebral CTA. Reviewing additional bolus trigger slices will improve diagnostic sensitivity. Despite high specificity, scout views and trigger slices offer a moderate sensitivity. Evaluation of scout views and trigger slices can result in medical treatment.

Age-related differences in the activity of arterial mineral deposition and regional bone metabolism: a 18F-sodium fluoride positron emission tomography study.

UNLABELLED: Functional (18)F-fluoride PET demonstrated an inverse relationship between the activity of arterial mineral deposition and regional bone metabolism. While bone metabolism decreases with age, the activity of arterial mineral deposition increases. INTRODUCTION: The extent of arterial calcification increases with age, whereas bone mineral density decreases, evidencing a well-known inverse correlation on morphological basis. The aim of this study was to evaluate the functional relationship between the activity of arterial mineral deposition and regional bone metabolism as assessed by (18)F-sodium fluoride (NaF) PET/CT. METHODS: Three hundred four subjects were examined by (18)F-NaF PET/CT. Tracer accumulation in the femoral arteries was analyzed both qualitatively and semiquantitatively by measuring the blood-pool-corrected standardized uptake value (target-to-background ratio). Uptake was compared with cardiovascular risk factors (RFs), calcified plaque burden, and regional bone metabolism as assessed by PET/CT. RESULTS: The activity of arterial mineral deposition significantly increased with age (p < 0.001), whereas regional bone metabolism significantly decreased (p < 0.001). There was a significant inverse correlation between bone metabolism and arterial mineral deposition (unadjusted, p < 0.001); that association was not significant (p = 0.79) when controlled for age and other RFs. Both high activity of arterial mineral deposition and low bone metabolism were significantly associated with cardiovascular events and other RFs. CONCLUSION: (18)F-NaF PET/CT provides a tool to visualize and quantify the activity of arterial mineral deposition and regional bone metabolism. In this study, we observed an inverse correlation between the activity of arterial mineral deposition and regional bone metabolism. While the activity of arterial mineral deposition significantly increases with age, regional bone metabolism decreases.

Significance of clinical examination, CT and MRI scan in the diagnosis of posterior pelvic ring fractures.

INTRODUCTION: Patients with a fracture in the anterior pelvic ring often simultaneously demonstrate pain in the posterior pelvic ring. The aim of the present prospective study was to assess the sensitivity of CT, MRI and clinical examination in the detection of fractures in the posterior pelvic ring in patients with fractures of the anterior pelvic ring diagnosed in conventional radiographs. METHODS: Sixty patients with radiographic signs of an anterior pelvic ring injury were included in this prospective analysis. Following a focused clinical examination of the posterior pelvis, all patients underwent both a CT and then a MRI scan of their pelvis. Two board certified radiologists evaluated the CT and MRI scans independently. To estimate the presence of osteoporosis the Hounsfield units of the vertebral body of L5 were measured in each case. RESULTS: Fifty-three women and seven men, with a mean age of 74.7+/-15.6 years were included into the study. A fracture of the posterior pelvic ring was found in fourty-eight patients (80%) patients using MRI. Fractures of the posterior pelvic ring would have been missed in eight cases (17%), if only CT had been used. Eighty-five percent of the patients with a posterior fracture had an osteoporosis. The majority of the cases suffered from a low energy trauma. Thirty-eight patients (83%) with positive clinical signs at the posterior pelvic ring actually had a fracture of the posterior pelvic ring in the MRI. The clinical examination proved to be equally effective to CT in detecting posterior pelvic ring fractures. CONCLUSION: The significance of both, clinical examination and CT was confirmed in the detection of fractures in the posterior pelvic ring. MRI examination of the pelvis however, was found to be superior in detecting undislocated fractures in a cohort of patients with a high incidence of osteoporosis. Using MRI may be beneficial in select cases, especially when reduced bone density is suspected.

Impact of a 4th generation iterative reconstruction technique on image quality in low-dose computed tomography of the chest in immunocompromised patients.

PURPOSE: To determine the image quality of an iterative reconstruction (IR) technique in low-dose MDCT (LDCT) of the chest of immunocompromised patients in an intraindividual comparison to filtered back projection (FBP) and to evaluate the dose reduction capability. MATERIALS AND METHODS: 30 chest LDCT scans were performed in immunocompromised patients (Brilliance iCT; 20-40 mAs; mean CTDIvol: 1.7 mGy). The raw data were reconstructed using FBP and the IR technique (iDose4™, Philips, Best, The Netherlands) set to seven iteration levels. 30 routine-dose MDCT (RDCT) reconstructed with FBP served as controls (mean exposure: 116 mAs; mean CDTIvol: 7.6 mGy). Three blinded radiologists scored subjective image quality and lesion conspicuity. Quantitative parameters including CT attenuation and objective image noise (OIN) were determined. RESULTS: In LDCT high iDose4™ levels lead to a significant decrease in OIN (FBP vs. iDose7: subscapular muscle 139.4 vs. 40.6 HU). The high iDose4™ levels provided significant improvements in image quality and artifact and noise reduction compared to LDCT FBP images. The conspicuity of subtle lesions was limited in LDCT FBP images. It significantly improved with high iDose4™ levels (> iDose4). LDCT with iDose4™ level 6 was determined to be of equivalent image quality as RDCT with FBP. CONCLUSION: iDose4™ substantially improves image quality and lesion conspicuity and reduces noise in low-dose chest CT. Compared to RDCT, high iDose4™ levels provide equivalent image quality in LDCT, hence suggesting a potential dose reduction of almost 80%.

Shiga toxin-producing E. coli O104:H4 outbreak 2011 in Germany: radiological features of enterohemorrhagic colitis.

PURPOSE: In 2011 a nationwide outbreak of Shiga toxin-producing E. coli (STEC) O104:H4 infection occurred in Germany with severe hemorrhagic colitis and hemolytic-uremic syndrome (HUS). We defined abdominal radiologic findings in these patients and correlated them with clinical parameters. MATERIALS AND METHODS: 23 patients (7 men; age: 48 ± 19 years) with O104:H4 colitis and/or HUS received abdominal CT (n = 12) or radiographs (n = 11). Colonic distension, air-fluid levels, and free intraabdominal air were assessed. Colonic wall thickening, contrast enhancement, pericolic stranding, and ascites were evaluated on CT. Laboratory parameters and clinical presentation were reviewed. Chi-square test, Student's t-test, McNemar's test and Spearman correlation were performed. RESULTS: Colonic lumen distension was seen in 16/23 patients (69.6 %). The ascending colon (11/23 patients; 47.8 %) and transverse colon (12/23 patients; 52.2 %) were dilated significantly more often (p = 0.006 and p = 0.003, respectively) than the descending colon (1/23; 4.3 %). All 12 patients undergoing CT scanning had abnormally thickened colonic wall segments, 3 (25 %) had pancolic involvement and 9 (75 %) had segmental involvement. The descending colon was predominantly affected (11/12 patients; 91.7 %) and thickened significantly more often than other colonic segments (p < 0.001). CONCLUSION: The segmental type of STEC O104:H4 colitis mainly affects the descending colon with upstream distension of the transverse/ascending colon and differs from other types of colitis.

Quantitative assessment of bone marrow attenuation values at MDCT: an objective tool for the detection of bone bruise related to occult sacral insufficiency fractures.

OBJECTIVES: To prove the feasibility of using Hounsfield attenuation values at MDCT to detect bone bruises related to sacral insufficiency fractures. METHODS: Twenty-two patients with acute sacrum trauma and no fracture findings at MDCT were included in our prospective study. Two observers independently reviewed CTs regarding visual signs of bone bruises in 132 defined regions of the sacral alae. Interobserver agreement was tested by κ statistics. Subsequently, HU values were obtained in the same regions, and attenuation differences between the two sides were calculated. Validity and reliability were assessed by intraclass correlation coefficient and Bland-Altman analysis. HU differences were subjected to ROC curve analysis to determine sensitivity, specificity, PPV and NPV. MRI served as standard reference. RESULTS: MRI revealed 19 regions with bone bruises and associated sacral insufficiency fractures. HU measurements demonstrated good validity and reliability (r = 0.989). ROC curve analysis exhibited an ideal cutoff value of 35.7 HU density difference between affected and non-affected regions. Visual evaluation revealed moderate agreement (κ = 0.48); diagnostic accuracy was inferior to objective evaluation. CONCLUSIONS: Assessment of differences in bone marrow density by HU measurements is an objective and reliable tool for detection of bone bruises associated with occult sacral insufficiency fractures. KEY POINTS : • Bone bruising is associated with occult sacral insufficiency fractures. • Assessment of differences in bone marrow CT attenuation appears valid and reliable. • Comparative HU measurements of bone marrow allow detection of bone bruises. • Comparative HU measurements have high specificity and negative predictive values. • Comparative HU measurements may make further diagnostic workup with MRI unnecessary.

Age-related incidence of pulmonary embolism and additional pathologic findings detected by computed tomography pulmonary angiography.

OBJECTIVE: To compare the incidence of pulmonary embolism (PE) and additional pathologic findings (APF) detected by computed tomography pulmonary angiography (CTPA) according to different age-groups. MATERIALS AND METHODS: 1353 consecutive CTPA cases for suspected PE were retrospectively reviewed. Patients were divided into seven age groups: ≤29, 30-39, 40-49, 50-59, 60-69, 70-79 and ≥80 years. Differences between the groups were tested using Fisher's exact or chi-square test. A p-value<0.0024 indicated statistical significance when Bonferroni correction was used. RESULTS: Incidence rates of PE ranged from 11.4% to 25.4% in different age groups. The three main APF were pleural effusion, pneumonia and pulmonary nodules. No significant difference was found between the incidences of PE in different age groups. Furthermore, APF in different age groups revealed no significant differences (all p-values>0.0024). CONCLUSION: The incidences of PE and APF detected by CTPA reveal no significant differences between various age groups.

Comparison of diagnostic accuracy of Magnetic Resonance Imaging and Multidetector Computed Tomography in the detection of pelvic fractures.

OBJECTIVE: To compare diagnostic accuracy and interobserver reliability of Magnetic Resonance Imaging (MRI) and Multidetector Computed Tomography (MDCT) in the detection of acute pelvic fractures. MATERIALS AND METHODS: In 38 consecutive patients (mean age 74.7 years) with a positive finding of anterior pelvis fracture in the conventional X-rays, pelvic MRI and MDCT were performed for further evaluation of pelvic ring fractures. Two radiologists independently read all data sets. Sensitivity and specificity were calculated based on mean scores for each method. Sensitivities of CT and MRI were compared using a paired proportion test (McNemar). Diagnostic validity of both methods was assessed by the interobserver variability using kappa statistics. Combined clinical data and findings from all imaging studies served as the reference standard. RESULTS: 122 fractures were identified in the reference standard (37 sacral, 58 pubic, 22 acetabular, 1 ischial, 4 ilial). On average, MRI detected 96.3% whereas CT detected 77% of all fractures. With regard to sensitivity, MRI proved to be significantly better compared to MDCT (observer 1, p=0.0009; observer 2, p=0.0003 by observer 2). In particular, MRI performed better in the depiction of sacral fractures, reaching a sensitivity of 98.6% compared to 66.1% at CT. The interobserver variability was determined to be very good (k=0.955 for MRI and 0.902 for MDCT). CONCLUSION: MRI reaches a significantly higher sensitivity than CT in the detection of acute pelvic fractures, particularly of the sacrum. Especially in elderly patients with suspicion of a sacral fracture and negative results at MDCT, MRI may be considered as the next step in diagnostic workup.

Accuracy of thoracic aortic measurements assessed by contrast enhanced and unenhanced magnetic resonance imaging.

AIM: To assess, whether unenhanced balanced steady-state-free precession sequences provide axial thoracic aortic measurements comparable to contrast enhanced magnetic resonance angiography with good intra- and interobserver agreement. MATERIALS AND METHODS: Enhanced and unenhanced sequences of the thoracic aorta in 23 consecutive patients were evaluated. Axial thoracic aortic diameters were measured at predefined levels by two independent readers. Pearson's correlation coefficient and Bland-Altman analysis were used to compare enhanced and unenhanced sequences. t-Test was used to determine possible significant differences between the measurements obtained by enhanced and unenhanced sequences. A p-value of less than .05 indicated statistical significance. Intraclass correlation coefficient and Bland-Altman were used for inter- and intraobserver correlation and agreement. RESULTS: There was no significant difference in diameter measurements between enhanced and unenhanced sequences (ascending aorta, p=0.98; descending aorta, p=0.52). Bland-Altman revealed good agreement between enhanced and unenhanced sequences for ascending (mean bias, -0.01cm; with 95% limits of agreement, ±0.30cm) and descending aortic diameters (mean bias, 0.05cm; with 95% limits of agreement, ±0.30cm). Inter- and intraobserver agreement (mean bias, less than ±0.15; with 95% limits of agreement, less than ±0.42cm for all measurements) as well as correlation (r>0.8 for all measurements) were excellent. CONCLUSION: Unenhanced balanced steady-state-free precession sequences enable rapid and accurate determination of axial thoracic aortic diameters with excellent inter- and intraobserver agreement, but without the risk of contrast media associated side-effects.

Diffusion weighted MRI and 18F-FDG PET/CT in non-small cell lung cancer (NSCLC): does the apparent diffusion coefficient (ADC) correlate with tracer uptake (SUV)?

INTRODUCTION: To investigate the potential correlation of the apparent diffusion coefficient assessed by diffusion-weighted MRI (DWI) and glucose metabolism determined by the standardized uptake value (SUV) at 18F-FDG PET/CT in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: 18F-FDG PET/CT and DWI (TR/TE, 2000/66 ms; b-values, 0 and 500 s/mm(2)) were performed in 41 consecutive patients with histologically verified NSCLC. Analysing the PET-CT data calculation of the mean (SUV(mean)) and maximum (SUV(max)) SUV was performed. By placing a region-of-interest (ROI) encovering the entire tumor mean (ADC(mean)) and minimum ADC (ADC(min)) were determined by two independent radiologists. Results of 18F-FDG PET-CT and DWI were compared on a per-patient basis. For statistical analysis Pearson's correlation coefficient, Bland-Altman and regression analysis were assessed. RESULTS: Data analysis revealed a significant inverse correlation of the ADC(min) and SUV(max) (r=-0.46; p=0.032). Testing the correlation of the ADC(min) and SUV(max) for each histological subtype separately revealed that the inverse correlation was good for both adenocarcinomas (r=-0.47; p=0.03) and squamouscell carcinomas (r=-0.71; p=0.002), respectively. No significant correlation was found for the comparison of ADC(min) and SUV(mean) (r=-0.29; p=0.27), ADC(mean) vs. SUV(mean) (r=-0.28; p=0.31) or ADC(mean) vs. SUV(max) (r=-0.33; p=0.23). The κ-value of 0.88 indicated a good agreement between both observers. CONCLUSION: This preliminary study is the first to verify the relation between the SUV and the ADC in NSCLC. The significant inverse correlation of these two quantitative imaging approaches points out the association of metabolic activity and tumor cellularity. Therefore, DWI with ADC measurement might represent a new prognostic marker in NSCLC.