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.

Does gamma-glutamyltransferase correlate with liver tumor burden in neuroendocrine tumors?

PURPOSE

In patients with neuroendocrine tumors (NETs) and liver metastases, increased gamma-glutamyltransferase (GGT) is commonly assumed as an indicator for progressive disease. To date, however, empirical data are lacking. This study aimed to investigate associations between GGT and liver tumor burden. In longitudinal analyses, associations of GGT and radiographic responses of liver metastases under therapy were investigated.

METHODS

The cross-sectional sample consisted of 104 patients who were treated at the University Medical Center Hamburg-Eppendorf from 2008 to 2021 (mean age 62.3 ± 12.6 years, 58.7% male). GGT and liver imaging were identified in a time range of 3 months. Radiologic reassessments were performed to estimate liver tumor burden. In a separate longitudinal sample (n = 15), the course of GGT levels under chemotherapy was analyzed. Data were retrospectively analyzed with a univariate ANOVA, linear regression analyses, and Wilcoxon tests.

RESULTS

Of 104 cross-sectionally analyzed patients, 54 (51.9%) showed a GGT elevation. GGT levels and liver tumor burden were positively correlated (p < 0.001), independently from age, gender, primary tumor location, grading, and cholestasis. Notably, GGT increase was associated with a liver tumor burden of >50%. In the longitudinal sample, 10 of 11 patients with progressive disease showed increasing GGT, whereas 4 of 4 patients with regressive disease showed declining GGT.

CONCLUSION

Our findings indicate that GGT is associated with liver tumor burden. Over the course of therapy, GGT appears to change in line with radiographic responses. Further longitudinal studies with larger sample sizes are required to define GGT as a reliable marker for tumor response.

Longitudinal follow-up by MR angiography reveals progressive dilatation of the distal aorta after aortic root replacement in Marfan syndrome

OBJECTIVES

To define and compare growth rates of the distal aorta in Marfan patients with and without aortic root replacement using serial MR angiography (MRA).

METHODS

We retrospectively included 136 Marfan patients with a total of 645 MRAs who underwent a median of five MRAs (range: 2-13) at 1.5 T and 3 T in annual intervals. Of these, 41 patients (34.8 ± 12 years) had undergone aortic root replacement. The remaining 95 patients (29.0 ± 17 years) still had a native aorta and served as the control group. Thoracic aortic diameters were independently measured at eleven predefined levels. Estimated growth rates were calculated using a mixed effects model adjusted for sex, age, BMI, and medication.

RESULTS

Marfan patients with aortic root replacement revealed the highest mean estimated growth rate in the proximal descending aorta (0.77 mm/year, CI: 0.31-1.21). Mean growth rates at all levels of the distal thoracic aorta were significantly higher in patients with aortic root replacement (0.28-0.77 mm/year) when compared to patients without aortic root replacement (0.03-0.07 mm/year) (all p < 0.001). Antihypertensive medication, gender, and BMI had no significant impact on the distal aortic growth rates.

CONCLUSION

Distal thoracic aortic diameters increase at a significantly higher rate in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. Further studies are warranted to investigate if the increased growth rate of the distal thoracic aorta after aortic root replacement is caused by altered hemodynamics due to the rigid aortic root graft or due to the general genetic disposition of post-operative Marfan patients.

CLINICAL RELEVANCE STATEMENT

High growth rates of the distal aorta after aortic root replacement underline the need for careful life-long aortic imaging of Marfan patients after aortic root replacement.

KEY POINTS

• Aortic growth rates in Marfan patients with aortic root replacement are highest in the mid-aortic arch, the proximal- and mid-descending aorta. • Growth rates of the distal thoracic aorta are significantly higher in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. • Antihypertensive medication, gender, and BMI have no significant impact on distal aortic growth rates in Marfan patients.

Association of medial collateral ligament complex injuries with anterior cruciate ligament ruptures based on posterolateral tibial plateau injuries

BACKGROUND

The combined injury of the medial collateral ligament complex and the anterior cruciate ligament (ACL) is the most common two ligament injury of the knee. Additional injuries to the medial capsuloligamentous structures are associated with rotational instability and a high failure rate of ACL reconstruction. The study aimed to analyze the specific pattern of medial injuries and their associated risk factors, with the goal of enabling early diagnosis and initiating appropriate therapeutic interventions, if necessary.

RESULTS

Between January 2017 and December 2018, 151 patients with acute ACL ruptures with a mean age of 32 ± 12 years were included in this study. The MRIs performed during the acute phase were analyzed by four independent investigators-two radiologists and two orthopedic surgeons. The trauma impact on the posterolateral tibial plateau and associated injuries to the medial complex (POL, dMCL, and sMCL) were examined and revealed an injury to the medial collateral ligament complex in 34.4% of the patients. The dMCL was the most frequently injured structure (92.2%). A dMCL injury was significantly associated with an increase in trauma severity at the posterolateral tibial plateau (p < 0.02) and additional injuries to the sMCL (OR 4.702, 95% CL 1.3-133.3, p = 0.03) and POL (OR 20.818, 95% CL 5.9-84.4, p < 0.0001). Isolated injuries to the sMCL were not observed. Significant risk factors for acquiring an sMCL injury were age (p < 0.01) and injury to the lateral meniscus (p < 0.01).

CONCLUSION

In about one-third of acute ACL ruptures the medial collateral ligament complex is also injured. This might be associated with an increased knee laxity as well as anteromedial rotational instability. Also, this might be associated with an increased risk for failure of revision ACL reconstruction. In addition, we show risk factors and predictors that point to an injury of medial structures and facilitate their diagnosis. This should help physicians and surgeons to precisely diagnose and to assess its scope in order to initiate proper therapies. With this in mind, we would like to draw attention to a frequently occurring combination injury, the so-called "unlucky triad" (ACL, MCL, and lateral meniscus). Level of evidence Level III Retrospective cohort study.

Spleen volume and length determined by computed tomography impact outcome after allogeneic stem cell transplantation for myelofibrosis

Splenomegaly is a hallmark of myelofibrosis (MF), and reports on the impact of spleen size on the outcome of allo-HSCT have been conflicting, possibly due to differences in methods of assessment. We retrospectively analysed the impact of spleen volume and length measured by computed tomography on allo-HSCT outcome in 93 patients, 74% of whom had prior ruxolitinib treatment. Median spleen volume and length were 1.58 dm3 and 20 cm, respectively. We found a strong correlation between spleen volume and length (Pearson's r = 0.95, p < 0.001), Spearman (rho = 0.96, p < 0.001). After a median follow-up of 41.7 months, 5-year overall and disease-free survival were 66% and 59%, respectively. Spleen size did not impact overall survival or non-relapse mortality. Larger spleen volume and length as continuous variables were associated with slower platelet and leucocyte engraftment and a higher risk of disease relapse in univariate and multivariate analyses. Spleen length measured precisely by imaging is a good surrogate for spleen volume. In the era of JAK inhibitors, larger spleen size reflects advanced disease in MF and is associated with an increased risk of relapse but has no impact on non-relapse mortality and overall survival after allo-HSCT.

Bi-planar calibration method for templating of hip joint arthroplasty: phantom study and proof of concept

PURPOSE

Calibration of radiographs is a critical step in digital templating for hip arthroplasty. Calibration errors of > 1.5% lead to over- or undersizing of the templated implants and may affect logistics and patient safety. Contemporary calibration methods are known to be imprecise with average errors of 6.5% and wide variance. A novel bi-planar radiograph-based calibration method is proposed, and a phantom study was conducted as proof of concept.

METHODS

A spherical external calibration marker (ECM) is placed in front of the pubic symphysis of a pelvic bone model at twelve different positions. For each marker position, standard anteroposterior radiographs and four corresponding lateral radiographs with different degrees of rotation (0°-30°) are taken (overall, 60 radiographs). Calibration factors are calculated for an internal calibration marker (ICM) at the centre of the right hip (reference) and the ECM using a novel algorithm. Rotation and marker positions simulate foreseeable use errors and misplacements and aim to test robustness of the method against these errors.

RESULTS

ECM calibration factor was 125.9% (range 124.7-127.2), and the mean ICM calibration factor was 126.6% (range 126.2-127.1) ([Formula: see text]). Four images (8.3%) were beyond the 1% error threshold (all with 30° rotation). The mean difference was 0.79% (SD 0.49).

CONCLUSION

The bi-planar method precisely predicts the true calibration factor of the hip joint plane under various conditions. In lateral radiographs, rotation of up to 20° did not adversely affect the precision and all images had calibration errors below the threshold for clinical significance.

Pre-interventional assessment of right renal to right adrenal vein distance: Impact on procedure time and radiation dose in adrenal vein sampling

PURPOSE

Adrenal vein sampling (AVS) is the reference standard for evaluation of lateralized hormone production in primary aldosteronism. We aimed to investigate the impact of pre-interventional right renal vein (RRV) to right adrenal vein (RAV) distance measurement on fluoroscopy time, contrast agent exposure and radiation dose during AVS.

MATERIALS AND METHODS

Forty-five patients with primary aldosteronism undergoing AVS were enrolled in our retrospective study and divided into three groups. In the group "ruler" (n = 14), RRV-RAV-distances were determined pre-interventionally by cross-sectional imaging (CT/MRI) and AVS was performed by one interventional radiologist with limited experience in AVS. CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances were correlated for aimed cannulation of the RAV. Patients in group "no ruler" (n = 24, three interventional radiologists with limited experience in AVS) and in group "expert", (n = 7, one expert interventional radiologist) underwent AVS without pre-interventional estimation of RRV-RAV-distances. Procedure parameters (fluoroscopy time, contrast agent volume, radiation dose) of group "ruler" were compared to both other groups by Kruskal-Wallis rank-sum test.

RESULTS

Correlation of CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances was good (r = 0.74;p = 0.003). The median RRV-RAV-distance was 4.5cm at CT/MRI (95%-CI:4.2-5.0cm) and 4.0cm at fluoroscopy (95%-CI:3.8-4.5cm). Fluoroscopy time (p<0.0001), contrast agent exposure (p = 0.0003) and radiation dose (air kerma and dose area product both p = 0.038) were significantly lower in group "ruler" compared to group "no ruler" (all p<0.05), and similar to group "expert" (all p>0.05).

CONCLUSIONS

CT/MRI-derived pre-interventional renal-adrenal vein distance measurements correlate well with angiographic distance measurements. Pre-interventional estimation of the RRV-RAV-distance allows for aimed cannulation of the RAV with potential reduction of fluoroscopy time, contrast agent exposure and radiation-dose during AVS.

The Influence of Surgical Realignment Procedures on Dynamic Patellar Tracking: A Dynamic Magnetic Resonance Imaging-Controlled Feasibility Study

Persisting patellar maltracking following surgical realignment often remains unseen. The aim of this study was to analyze the effects of realignment procedures on patellofemoral kinematics in patients with patellofemoral instability (PFI) and patellofemoral maltracking (PM) by using dynamic magnetic resonance imaging (MRI). Patients planned for surgical patellar realignment due to PFI and a clinically and radiologically apparent PM between December 2019 and May 2022 were included. Patients without PM, limited range of motion, joint effusion, or concomitant injuries were excluded. Dynamic mediolateral translation (dMPT) and patella tilt (dPT) were measured preoperatively and three months postoperatively. In 24 patients (7 men, 17 women; mean age 23.0 years), 10 tibial tubercle transfers, 5 soft tissue patella tendon transfers, 6 trochleoplasties, 3 lateral lengthenings, 1 varizating distal femoral osteotomy (DFO), and 1 torsional DFO were performed. At final follow-up, dMPT (from 10.95 ± 5.93 mm to 4.89 ± 0.40 mm, p < 0.001) and dPT (from 14.50° ± 10.33° to 8.44° ± 7.46°, p = 0.026) were significantly improved. All static radiological parameters were corrected to physiological values. Surgical patellar realignment contributed to the significant improvement of patellofemoral kinematics, with an approximation to normal values. The postoperative application of dynamic MRI allowed for a quantification of the performed correction, allowing for a postoperative control of success.

[Intimal pulmonary sarcoma: A case report of a rare differential diagnosis of chronic thromboembolic pulmonary hypertension]

Pulmonary angiosarcoma is a rare and malignant disease of the blood vessels. Initially, it can be misdiagnosed as chronic thromboembolic hypertension (CTEPH). In CTEPH, there is increased pressure and resistance of the pulmonary arteries following persistent obstruction of pulmonary circulation from (recurrent) thromboembolism despite adequate anticoagulative treatment.A 76-year-old patient was referred to our centre for pulmonary hypertension after a central, left-sided, subacute pulmonary thromboembolism had been observed 7 months earlier. It was treated with apixaban, but the patient described persistent dyspnoea and cough. We observed severely reduced diffusion capacity, ineffective ventilation during cardiopulmonary exercise testing and right heart strain on echocardiograph, signs that are in agreement with suspected CTEPH. Computer tomography of the chest showed a persistent, size-constant obliteration of the left main pulmonary artery, and ventilation perfusion scan confirmed complete interruption of perfusion. We suspected malignancy; PET-CT scan confirmed metabolically active lesions. Histopathological examination of a sample obtained from the lesion by endobronchial ultrasound-guided needle aspiration showed a sarcomatous tumour with amplification of the MDM2-gene. We diagnosed an intimal angiosarcoma of the left pulmonary artery and referred the patient to pneumectomy.Angiosarcoma of the pulmonary arteries is a rare differential diagnosis of persistent thrombotic lesion and suspected CTEPH. In 2015 there were less than 300 cases described.Pulmonary angiosarcoma should be considered if: lesion occupies the entire lumen of pulmonary arteries with dilatation, contrast enhancement and infiltration of the wall in radiological examination, FDG-PET CT reveals metabolically active lesions, no pulmonary thromboembolism was documented in the anamnesis, increase in size is seen despite anticoagulation, patient presents with B symptoms.Diagnosis confirmed by biopsy, resection of tumour and removal of metastases is the therapeutic standard. Median survival remains poor. Further research is needed for improved diagnosis and treatment.

Magnetic resonance angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome

Background

To identify magnetic resonance (MR) angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome.

Material and methods

We retrospectively included 111 patients (32.7±16.5 years, range: 7–75 years) with a total of 446 MR angiographies. Aortic diameter growth rates of the entire thoracic aorta and Z-scores were estimated from annual diameter measurements. Aortic root shape was subdivided into three different types: (T0) normal; (T1) localized dilatation; (T2) generalized aortic root dilatation. Aortic diameter, Z-score, age, and aortic root shape at baseline were tested as predictors of aortic root dilatation using a multivariate logistic regression model.

Results

The highest aortic growth rate was observed at the level of the sinuses of Valsalva. Higher aortic root diameters and Z-scores at baseline predicted an increased growth of the aortic root (p = 0.003 and p<0.001). Young age (<30 years) was a predictor for the increase of Z-scores when compared to patients ≥30 years (p = 0.019). 25/111 patients (22.5%) had a T0 aortic root shape, 59/111 patients (53.2%) had a T1 aortic root shape, and 27/111 patients (24.3%) had a T2 aortic root shape. Aortic root shape did not predict further aortic growth (p>0.05). However, significantly more patients undergoing surgery had a generalized aortic dilatation (19/28, 76.9%) than a localized aortic root dilatation (9/28, 32.1%) (p = 0.001).

Conclusion

Larger baseline aortic root diameter and Z-score as well as young age predict solely progressive aortic root dilatation in Marfan patients. MR angiography derived type of aortic root shape does not predict aortic growth, but patients with generalized aortic root dilatation are referred more frequently for aortic surgery.

Localization Defines Streptozotocin/5-FU Response in Primary Pancreatic Neuroendocrine Tumours

INTRODUCTION

Incidence of pancreatic neuroendocrine tumours (pNETs) is on the rise. The only curative treatment is surgical resection in localized or oligo-metastatic disease. However, patients may present with locally advanced or unresectable primary tumours. So far, no conversion therapy to achieve resectability has been established, which is partly due to lack of data on primary tumour response to therapies. Here, we specifically evaluate the primary tumour response to streptozocin/5-FU in a large cohort of metastatic pNET patients.

METHODS

Five ENETS centres in Germany contributed 84 patients to the study cohort for retrospective analysis.

RESULTS

Overall response rate (ORR) in primary tumours was 34% and disease control rate (DCR) 88%. ORR was different in metastases at 44% and DCR at 70%. Partial remission in primary tumours was more frequent among those located in pancreatic tail than that in pancreatic head (49% vs. 14%, p = 0.03). Correspondingly, metastases from tumours originating from pancreatic tail responded more frequently than metastases originating from pancreatic head (88.5% vs. 41.7%, p = 0.005). The median PFS of the primary tumours was longer than that in metastases (31 months vs. 16 months; p = 0.04). Considerable downsizing of the primary tumour was rare and occurred primarily in tumours located in the pancreatic tail.

CONCLUSION

STZ/5-FU can achieve disease stabilization in a high proportion of metastatic pNET patients. In the majority of cases however it does not induce substantial downsizing of the primary tumour, thus possibly limiting its potential as conversion chemotherapy. Furthermore, the difference in response rate observed between different primary tumour locations warrants further exploration.

Diagnostic yield of cone beam computed tomography for small foreign body detection in the hand in comparison with radiography, MSCT and MRI: an ex vivo study

INTRODUCTION

Detection of symptomatic foreign bodies (FB) after penetrating hand injuries can be challenging. Multiplanar radiography is most frequently used for FB detection and may be complemented by multislice computed tomography (MSCT) if suspected FBs cannot be identified and clinical symptoms are persisting. Cone beam computed tomography (CBCT) is a promising imaging modality for traumatology aside from fracture detection. The aim of this study was to evaluate the diagnostic yield of CBCT for different small FBs in the hand in comparison with radiography, MSCT and magnetic resonance imaging (MRI).

METHODS

In ten cadaveric hands of voluntary body donors, 20 different FBs (metal, glass, stone, wood, thorn) in predefined sizes (0.5, 1 and 2mm) were randomly placed in the central hand and the basal phalanges. All hands were imaged using radiography, 256-slice CT, CBCT, and 3T MRI. A total of 200 subcutaneous and intramuscular particles were analyzed for their visibility by two observers at two time points. The Cohens Kappa coefficient was calculated as a measure of interobserver agreement and intraobserver reliability. The particle detection rate between different imaging modalities was compared using McNemar Chi²-tests.

RESULTS

CBCT and MSCT provided a higher detection rate (94.6% and 86.3%) for detecting metal, glass and stone particles compared to standard radiography (70.0%; each p<0.001). MRI did not provide a diagnostic benefit. Wood particles and thorns were not reliably recognizable by any imaging technique. The interobserver agreement (K=0.768; p<0.001) and the intraobserver reliability for both observers (K₁=0.914 and K₂=0.907; p<0.001) were good. The dose length product (DLP) was 2-fold lower in CBCT than in MSCT (39.2 ± 2.1 vs. 81.4 ± 2.9 mGy*cm; p<0.001).

CONCLUSIONS

In this ex vivo study, CBCT provided a high detection rate for small metal, glass, and stone particles while the radiation exposure was significantly lower compared to MSCT. These results suggest that CBCT instead of MSCT seems a reasonable option in supplementary diagnostics to exclude of FBs. The primary use of CBCT instead of radiography may be considered for symptomatic patients with expected small radiopaque particles <1mm. Organic FBs can be visualized indirectly in MRI and CBCT/MSCT by entrapped surrounding air.

LEVEL OF EVIDENCE

Level I, diagnostic study.

Accuracy of preoperative CT staging of acute colonic diverticulitis using the classification of diverticular disease (CDD) - Is there a beneficial impact of water enema and visceral obesity?

PURPOSE

We evaluated the accuracy of preoperative CT in staging colonic diverticulitis (ACD) by using the classification of diverticular disease (CDD) and investigated the diagnostic impact of water enema (WE) and visceral obesity.

METHODS

In this retrospective study, the radiological and hospital information system was searched for patients who underwent CT for clinically suspected ACD prior to surgery between 2009 and 2019. From the initial population (n = 164), we included 155 patients (94.5 %) (85 women; mean age: 58 ± 13 years) matching the following inclusion criteria: i.) clinically suspected ACD, ii.) i.v. contrast-enhanced CT, iii.) surgery for ACD within 1 week after CT, iv.) histopathological report that proved ACD. The remaining 9 patients (5.5 %) were excluded because histopathological reports were lacking (n = 3) or CT was performed without intravenous contrast agent (n = 6). WE (+ butylscopolamine i.v.) was performed in 93 patients (group A, 60 %). 62 patients (group B, 40 %) had no WE. Visceral-to-subcutaneous fat ratio (V/S) was determined for each patient. Two radiologists blinded for final diagnosis independently staged ACD according to CDD and assessed prevalence and confidence ratings of ACD-related CT-findings: pericolonic fat stranding, covered- and free-perforation, local and generalized peritonitis, abscess. Interobserver-agreement of CT-findings were assessed and effects of WE and V/S ratio on the diagnostic accuracy of CT with surgical and histopathological findings as reference were determined by calculating a logistic regression model.

RESULTS

CT-staging showed high accuracy (94 %) and excellent interrater-correlation (ICC 0.96) for staging ACD. WE had no positive impact neither on diagnostic accuracy of staging, nor on confidence ratings of ACD-related CT-findings (all p > 0.5). Confidence ratings were significantly higher in examinations without WE for perforation, peritonitis as well as abscesses (all p < 0.5). Confidence ratings for the assessment of local peritonitis improved significantly with higher V/S (p = 0.049). The increase of V/S significantly correlated with the probability for correct CDD staging of ACD in CT (p = 0.023).

CONCLUSION

Increase of visceral obesity significantly improves accuracy of CT in preoperative staging acute colonic diverticulitis. However, independently of the degree of visceral obesity, water enema has no diagnostic benefit and may therefore be omitted. Overall, CT proves high accuracy in preoperative staging ACD using the classification of diverticular disease.

LEVEL OF EVIDENCE

Retrospective study, observational study.

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.

Non-contrast MR angiography at 1.5 Tesla for aortic monitoring in Marfan patients after aortic root surgery

BACKGROUND

Contrast-enhanced cardiovascular magnetic resonance angiography (CE-CMRA) is the established imaging modality for patients with Marfan syndrome requiring life-long annual aortic imaging before and after aortic root replacement. Contrast-free CMRA techniques avoiding side-effects of contrast media are highly desirable for serial imaging but have not been evaluated in the postoperative setup of Marfan patients. The purpose of this study was to assess the feasibility of non-contrast balanced steady-state free precession (bSSFP) magnetic resonance imaging for aortic monitoring of postoperative patients with Marfan syndrome.

METHODS

Sixty-four adult Marfan patients after aortic root replacement were prospectively included. Fourteen patients (22%) had a residual aortic dissection after surgical treatment of type A dissection. bSSFP imaging and CE-CMRA were performed at 1.5 Tesla. Two radiologists evaluated the images regarding image quality (1 = poor, 4 = excellent), artifacts (1 = severe, 4 = none) and aortic pathologies. Readers measured the aortic diameters at defined levels in both techniques. Statistics included observer agreement for image scoring and diameter measurements and ROC analyses for comparison of the diagnostic performance of bSSFP and CE-CMRA.

RESULTS

Both readers observed no significant differences in image quality between bSSFP and CE-CMRA and found a median image quality score of 4 for both techniques (all p > .05). No significant differences were found regarding the frequency of image artifacts in both sequences (all p > .05). Sensitivity and specificity for detection of aortic dissections was 100% for both readers and techniques. Compared to bSSFP imaging, CE-CMRA resulted in higher diameters (mean bias, 0.9 mm; p < .05). The inter-observer biases of diameter measurements were not significantly different (all p > .05), except for the distal graft anastomosis (p = .001). Using both techniques, the readers correctly identified a graft suture dehiscence with aneurysm formation requiring surgery.

CONCLUSION

Unenhanced bSSFP CMR imaging allows for riskless aortic monitoring with high diagnostic accuracy in Marfan patients after aortic root surgery.

Early time-related course of image findings in postmortem MRI: Typical findings and observer agreement in a porcine model

PURPOSE

To assess early time-related image findings in postmortem magnetic resonance imaging (MRI) and to evaluate observer agreement in a porcine model.

MATERIAL AND METHODS

Three pigs were examined by MRI at 15 different time points in the first 36h after death. Two observers independently recorded the postmortem interval (PMI) to the appearance of fluid collection (pleural space, interlobar and interlobular pulmonary fissures and hepatic interlobar fissures), gas accumulation (intrahepatic and intracardial) and blood clotting (aorta and intrahepatic venous vessels). Cohen's Kappa statistics and intraclass correlation coefficient (ICC) were used to evaluate intra- and interobserver agreement.

RESULTS

Intrahepatic gas was evident after 12, 17 and 30h. Also, intracardiac gas was present in all animals. However, no chronological appearance has been observed. Blood clotting in the hepatic vein was observed within 3min, aortic clotting with a delay of 2-12h after death. Interlobular pulmonary fluid (median PMI: 2h, range 2-2h), pleural effusion (median PMI: 10.5h, range 9-12h) and hepatic interlobar fissure fluid (median PMI: 11.5h, range 11-12h) displayed a chronological appearance pattern. Qualitative and quantitative detection of most postmortem findings showed excellent intra- and interobserver agreement with Kappa values>0.8 or ICC>0.75.

CONCLUSION

Pulmonary and hepatic fissural fluid collection as well as intravasal gas accumulation are early time-related image findings in postmortem MRI. The chronological appearance of these findings can be assessed with excellent observer agreement in a porcine model.

CT angiography in the setting of suspected acute mesenteric ischemia: prevalence of ischemic and alternative diagnoses

PURPOSE

The purpose of the study was to determine the prevalence of ischemic and alternative diagnoses and the diagnostic accuracy of CT angiography (CTA) in the setting of suspected acute mesenteric ischemia (AMI).

MATERIAL AND METHODS

We included 959 patients undergoing CTA for the evaluation of suspected AMI. The final clinical diagnosis was used to determine the prevalence of ischemic and alternative diagnoses and to calculate the diagnostic accuracy of CTA. Prevalence of diagnoses by age, sex, and admission status was compared using Cochran-Armitage and χ ² tests.

RESULTS

Prevalence was 18.8% (180/959) for AMI and 61.2% (587/959) for specific alternative diagnoses. In the remaining 20.0% (192/959), no clear clinical diagnosis was established. The most frequent alternative diagnoses were small-bowel obstruction (10.4%; 61/587), infectious colitis (8.7%; 51/587), pneumonia (6.5%; 38/587), cholecystitis (6.1%; 36/587), and diverticulitis (5.6%; 33/587). Prevalence of specific alternative diagnoses varied significantly according to both age (p < .013) and admissions status (p < 0.001). CTA had a sensitivity and specificity for diagnosing AMI of 89.4%/99.5% and for alternative diagnoses of 86.7%/96.9%, respectively.

CONCLUSION

In the setting of suspected AMI, the prevalence of ischemic and alternative diagnoses varies significantly by age, sex, and admission status. CTA provides for rapid and non-invasive assessment of ischemic and alternative diagnoses with high diagnostic accuracy.

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.

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.

Comparison of conventional radiography and MDCT in suspected scaphoid fractures

AIM: To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography (MDCT) in suspected scaphoid fractures.

METHODS: One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities.

RESULTS: Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients (42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT (P < 0.01) concerning scaphoid fracture detection. The mean effective dose of MDCT was 0.1 mSv compared to 0.002 mSv of conventional radiography.

CONCLUSION: Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma.

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

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.

Detection of occult vertebral fractures by quantitative assessment of bone marrow attenuation values at MDCT

OBJECTIVES

To determine a cut-off value of Hounsfield attenuation units (HU) at multidetector computed tomography (MDCT) for valid and reliable detection of bone marrow oedema (BME) related to occult vertebral fractures.

METHODS

36 patients underwent both MDCT and Magnetic Resonance Imaging (MRI) for evaluation of vertebral fractures of the thoracolumbar spine and were included in this retrospective study. Two readers independently assessed HU values at MDCT in a total of 196 vertebrae. Reliability was assessed by intraclass correlation coefficient and Bland-Altman analysis. For each patient we determined the vertebra with the lowest HU value and calculated the HU-difference to each other vertebral body. HU-differences were subjected to receiver operating characteristic (ROC) curve analysis to determine the diagnostic accuracy for detection of BME as determined by MRI, which served as the reference standard. Results of HU-measurements were compared with standard visual evaluation of MDCT.

RESULTS

HU measurements demonstrated a high interrater reliability (ICC=0.984). ROC curve analysis (AUC=0.978) exhibited an ideal cut-off value of 29.6 HU for detection of BME associated with vertebral fractures with an accuracy of 97.4% as compared to 93.4% accuracy of visual evaluation. Particularly, HU-measurements increased the sensitivity for detection of vertebral fractures from 78.0% to 92.7% due to the detection of 7 of 9 occult fractures that were missed by visual evaluation alone.

CONCLUSIONS

Assessing bone marrow density by HU measurements using the cut-off of 29.6 HU is a valid and reliable tool for detection of BME related to occult vertebral fractures in MDCT. The introduced technique may allow more accurate treatment decisions and may make further diagnostic work-up with MRI unnecessary.

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%.

The degree of articular depression as a predictor of soft-tissue injuries in tibial plateau fracture

PURPOSE

Magnetic resonance imaging (MRI) provides sufficient information with regard to specific soft-tissue injuries in the knee, but it is not generally used to evaluate acute tibial plateau fractures. The aim of the present study was to determine whether the amount of tibial plateau fracture depression on multi-detector computed tomography (MDCT) scans correlates with the incidence of associated soft-tissue injuries on MRI.

METHODS

A total of 54 consecutive patients with a mean age of 51.2 years (SD = 18.3) were included in this retrospective study. All patients were admitted to the emergency department of a university clinic with acute tibial plateau fracture. The amount of articular depression was assessed from MDCT scans. Magnetic resonance images were evaluated for crucial and collateral ligament injury, meniscal tears, and patellar retinaculum lesions.

RESULTS

Logistic regression revealed a significant impact of increasing tibial plateau fracture depression on the incidence of meniscus lateralis tears (P = 0.025) and anterior cruciate ligament lesions (P = 0.018). Analysis of covariance demonstrated a significant correlation between the amount of articular depression and absolute number of soft-tissue injuries (P = 0.001).

CONCLUSIONS

Articular depression is a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture. Magnetic resonance imaging is generally recommended with respect to associated soft-tissue injuries, especially in cases with distinct tibial plateau fracture depression on multi-detector computed tomography scans.

LEVEL OF EVIDENCE

Case series, Level IV.

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.

Magnetic resonance imaging in patients with granulomatosis with polyangiitis (Wegener's) and subglottic stenosis

OBJECTIVE

To evaluate the ability of MRI to detect subglottic stenosis and to differentiate between active and inactive subglottic inflammation in patients with granulomatosis with polyangiitis (GPA).

MATERIALS AND METHODS

MRI studies of the larynx of 18 GPA patients with suspected SGS were included. The MRI protocol included T1- and T2-weighted and STIR-sequences, dynamic contrast enhancement (DCE) and diffusion weighted imaging (DWI). Two independent observers reviewed the MR images. SGS were identified and quantified, inflammatory activity was assessed using edema imaging, DCE and DWI. Final MRI diagnoses were compared to the clinical, laryngoscopic and histopathologic results.

RESULTS

MRI confirmed SGS in all GPA patients with significant narrowing of the airway lumen and thickening of subglottic wall. Assessing the subglottic inflammatory activity, MRI showed a sensitivity of 87.5 % and a specificity of 60.0 %. Interrater agreement was κ = 0.769. Of the different MR technical approaches tested, edema imaging was most sensitive and specific. DWI led to significant differences in the apparent diffusion coefficient between active and inactive subglottic inflammation. No significant differences were found with DCE imaging.

CONCLUSION

MR imaging has shown the ability to detect and grade SGS in patients with GPA. It non-invasively assesses the status of inflammatory activity utilizing edema sensitive sequences and DWI.

Diffusion-weighted MR-imaging for the detection of pulmonary nodules at 1.5 Tesla: intraindividual comparison with multidetector computed tomography

INTRODUCTION

To investigate the feasibility of diffusion-weighted imaging (DWI) MRI for detecting pulmonary nodules at 1.5 Tesla in comparison with standard multidetector computed tomography (MDCT).

METHODS

Twenty patients with disseminated cancer disease in which MDCT had assured the presence of at least one pulmonary nodule were examined using a respiratory-gated DWI MR-sequence. Grey scale inverted source images and coronal maximum intensity projection (MIP) images were consensually analysed by two experienced radiologists. Size and location of any nodule detected were assessed. Additionally, the readers evaluated each hemithorax for the presence of at least one nodule and applied a four-point conspicuity scale (1-hemithorax definitely affected; 4-hemithorax definitely not affected). MDCT data served as reference.

RESULTS

At MDCT, a total of 71 pulmonary noduIes was found (size 3-5mm, n=16; 6-9mm, n=22; ≥10mm, n=33). For the DWI MR-sequence, a sensitivity of 86.4% was calculated for nodules ranging 6-9mm and 97% for nodules ≥10mm. In contrast, only 43.8% of lesions ≤5mm was detected. The separate analysis of each hemithorax for the presence of at least one pulmonary nodule revealed a specificity rate, PPV and NPV of DWI-MR of 92.3%, 96% and 80%, respectively.

CONCLUSIONS

The presented study is the first to confirm the diagnostic potential of DWI-MR in the detection of solid lung nodules. This technique allows for the detection of nodules ≥6mm with reasonably high sensitivity rates (>86%). The observation of false positive findings decreases the accuracy of this approach compared with MDCT.

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.

Correlation of serum level of high mobility group box 1 with the burden of granulomatous inflammation in granulomatosis with polyangiitis (Wegener's)

OBJECTIVES

To investigate the correlation of serum levels of high mobility group box 1 (HMGB1) with the extent of granulomatous inflammation in granulomatosis with polyangiitis (GPA).

METHODS

From 169 patients with GPA, 17 patients with granulomatous inflammation, without evidence of vasculitis were identified and 36 patients without measurable 'granuloma' formation. HMGB1 serum levels were determined and compared between the two groups, using a Mann-Whitney U test. Serum levels of 26 healthy individuals served as controls. In a further 21 patients with GPA with a pulmonary granulomatous manifestation from the study population, CT volumetry of 'granuloma' was performed. Volumes were compared with serum levels of HMGB1 (Spearman rank order test).

RESULTS

Serum levels of HMGB1 were significantly higher in patients with predominant granulomatous disease than in patients without measurable 'granuloma' manifestations (6.44 ± 4.53 ng/ml vs 3.85 ± 2.88 ng/ml; p=0.0107). In both groups, levels of HMGB1 were significantly higher than in controls (2.34 ± 2.01 ng/ml; p<0.01). A positive correlation of HMGB1 serum levels with volumes of pulmonary 'granuloma' (r=0.761, p<0.0017) was seen.

CONCLUSIONS

HMGB1 serum levels are significantly higher in GPA with predominant granulomatous manifestations and correlate with volumes of pulmonary 'granuloma'. HMGB1 may be used as a marker of the burden of granulomatous inflammation in GPA.

Intraindividual comparison of contrast-enhanced MRI and unenhanced SSFP sequences of stenotic and non-stenotic pulmonary artery diameters

PURPOSE

To evaluate the agreement of pulmonary artery diameters assessed with 3D contrast-enhanced MR angiography (CE-MRA) and a 2D balanced steady-state-free precession sequence (bSSFP) in non-stenotic and stenotic pulmonary arteries (PA).

METHODS AND MATERIALS

44 right and left PAs (30 non-stenotic and 14 stenotic) were examined in 23 consecutive patients by performing CE-MRA as well as bSSFP. Two independent readers determined the transverse diameters of the PA.

RESULTS

No significant difference in diameter measurements was found between CE-MRA and bSSFP (p = 0.8608 for the stenotic and p = 0.6208 for the non-stenotic PA). Bland-Altman analysis revealed good agreement between CE-MRA and bSSFP for both the non-stenotic (mean bias, 0.07 cm; with 95 % limits of agreement, ± 0.34 cm) and the stenotic (mean bias, 0.05 cm; with 95 % limits of agreement, ± 0.30 cm) PA.

CONCLUSION

bSSFP allows rapid and accurate determination of PA diameters without the use of ionizing radiation and the risk of contrast media-associated side-effects.