Quality assurance in CT: implementation of the updated national diagnostic reference levels using an automated CT dose monitoring system.

AIM: To evaluate the implementation of the updated computed tomography (CT) diagnostic reference levels (DRLs) from the German Federal Office for Radiation Protection into clinical routine using an automatic CT dose monitoring system. METHODS AND MATERIALS: CT radiation exposure was analysed before and after implementing the updated national DRLs into routine clinical work in 2016. After the implementation process, institutional CT protocols were mapped to the anatomical regions for which DRLs were provided. Systematically, protocols that exceeded the thresholds were optimised and analysed in detail. The CT radiation output parameters analysed were volumetric CT dose index (CTDIvol) and dose-length product (DLP). Three radiologists evaluated subjective image quality using a three-point Likert scale. RESULTS: The study included 94,258 CT series (from 27,103 CT examinations) in adult patients performed in 2016. When averaged over all body regions with available DRL, institutional CTDIvol/DLP values were always below the DRLs (65.2±32.9%/67.3±41.5% initially; 59.4±32%/60.5±39.9% after optimisation). Values exceeding the national DRLs were found for pelvis (n=268; CTDIvol 107.7±65.7%/DLP 106.3±79.3%), lumbar spine (n=91; 160.8±74.7%/175.2±104.1%), and facial bones (n=527; 108±39%/152.7±75.7%). After optimisation, CTDIvol and DLP were 87.9±73%/87.8±80.8% for the pelvis, 67.8±33.2%/74.5±50.6% for the lumbar spine and 95.1±45.8%/133.3±74.6% for the viscerocranium. CONCLUSION: An automatic CT dose monitoring system enabled not only comprehensive monitoring of a DRL implementation process but can also help to optimise radiation exposure.

Iterative metal artefact reduction in CT: can dedicated algorithms improve image quality after spinal instrumentation?

AIM: To investigate the value of dedicated computed tomography (CT) iterative metal artefact reduction (iMAR) algorithms in patients after spinal instrumentation. MATERIALS AND METHODS: Post-surgical spinal CT images of 24 patients performed between March 2015 and July 2016 were retrospectively included. Images were reconstructed with standard weighted filtered back projection (WFBP) and with two dedicated iMAR algorithms (iMAR-Algo1, adjusted to spinal instrumentations and iMAR-Algo2, adjusted to large metallic hip implants) using a medium smooth kernel (B30f) and a sharp kernel (B70f). Frequencies of density changes were quantified to assess objective image quality. Image quality was rated subjectively by evaluating the visibility of critical anatomical structures including the central canal, the spinal cord, neural foramina, and vertebral bone. RESULTS: Both iMAR algorithms significantly reduced artefacts from metal compared with WFBP (p<0.0001). Results of subjective image analysis showed that both iMAR algorithms led to an improvement in visualisation of soft-tissue structures (median iMAR-Algo1=3; interquartile range [IQR]:1.5-3; iMAR-Algo2=4; IQR: 3.5-4) and bone structures (iMAR-Algo1=3; IQR:3-4; iMAR-Algo2=4; IQR:4-5) compared to WFBP (soft tissue: median 2; IQR: 0.5-2 and bone structures: median 2; IQR: 1-3; p<0.0001). Compared with iMAR-Algo1, objective artefact reduction and subjective visualisation of soft-tissue and bone structures were improved with iMAR-Algo2 (p<0.0001). CONCLUSION: Both iMAR algorithms reduced artefacts compared with WFBP, however, the iMAR algorithm with dedicated settings for large metallic implants was superior to the algorithm specifically adjusted to spinal implants.

Dose monitoring using the DICOM structured report: assessment of the relationship between cumulative radiation exposure and BMI in abdominal CT.

AIM: To perform a systematic, large-scale analysis using the Digital Imaging and Communication in Medicine structured report (DICOM-SR) to assess the relationship between body mass index (BMI) and radiation exposure in abdominal CT. MATERIALS AND METHODS: A retrospective analysis of DICOM-SR of 3121 abdominal CT examinations between April 2013 and March 2014 was performed. All examinations were conducted using a 128 row CT system. Patients (mean age 61 ± 15 years) were divided into five groups according to their BMI: group A <20 kg/m(2) (underweight), group B 20-25 kg/m(2) (normal weight), group C 25-30 kg/m(2) (overweight), group D 30-35 kg/m(2) (obese), and group E > 35 kg/m(2) (extremely obese). CT dose index (CTDIvol) and dose-length product (DLP) were compared between all groups and matched to national diagnostic reference values. RESULTS: The mean CTDIvol and DLP were 5.4 ± 2.9 mGy and 243 ± 153 mGy.cm in group A, 6 ± 3.6 mGy and 264 ± 179 mGy.cm in group B, 7 ± 3.6 mGy and 320 ± 180 mGy.cm in group C, 8.1 ± 5.2 mGy and 375 ± 306 mGy.cm in group D, and 10 ± 8 mGy and 476 ± 403 mGy.cm in group E, respectively. Except for group A versus group B, CTDIvol and DLP differed significantly between all groups (p<0.05). Significantly more CTDIvol values exceeded national diagnostic reference values in groups D and E (2.1% and 6.3%) compared to group B (0.5%, p<0.05). CONCLUSION: DICOM-SR is a comprehensive, fast, and reproducible way to analyse dose-related data at CT. It allows for automated evaluation of radiation dose in a large study population. Dose exposition is related to the patient's BMI and is increased by up to 96% for extremely obese patients undergoing abdominal CT.

Clinical impact of hyperattenuation of adrenal glands on contrast-enhanced computed tomography of polytraumatised patients.

OBJECTIVE: To evaluate the prognostic value of hyperattenuating adrenal glands on contrast-enhanced CT of polytraumatised patients. METHODS: Two hundred ninety-two patients (195 men and 97 women, mean age 45.3 ± 23.3 years) were included in this retrospective study. CT examinations were performed 60 s after intravenous injection of contrast material. Image analysis was performed by two radiologists. Patients were assigned to one of two groups according to the attenuation of the adrenal gland [group 1: adrenal glands ≥ inferior vena cava (IVC); group 2: adrenal glands < IVC]. RESULTS: Eighteen patients (42.2 years ± 24.2) were assigned to group 1 and 274 patients (48.4 years ± 22.4) to group 2. The average adrenal density was 150.8 ± 36.1 HU in group 1 and 83.7 ± 23.6 HU in group 2 (P < 0.0001). Eight of the 18 patients in group 1 (44.4%) and 33 of the 274 patients in group 2 (12.4%) died during hospitalisation (P < 0.05). Mean adrenal enhancement was significantly higher in patients who died (101.9 ± 40.6 HU) compared with survivors (86.1 ± 27.0 HU; P < 0.001). CONCLUSION: Hyperattenuation of adrenal glands is associated with a higher mortality rate in polytraumatised patients and may serve as a predictor of poor clinical outcome. KEY POINTS: • Hyperattenuating adrenal glands can be observed in 6.2% of polytraumatised patients. • Hyperattenuating adrenal glands indicate poor clinical outcome in polytraumatised patients. • In polytraumatised patients, hyperattenuating adrenal glands are associated with a high mortality rate. • Adrenal enhancement is higher amongst patients who died than amongst survivors.

Evaluation of automated attenuation-based tube potential selection in combination with organ-specific dose reduction for contrast-enhanced chest CT examinations.

AIM: To evaluate the influence of attenuation-based tube potential selection (ATPS) in combination with organ-specific dose reduction (OSDR) on radiation dose and image quality of contrast-enhanced chest computed tomography (CT) examinations. MATERIAL AND METHODS: Seventy consecutive patients (59.2 ± 16.1 years; 49 men; 21 women) were randomized into two groups and underwent contrast-enhanced chest CT using a 128 section CT scanner. CT examinations were performed as standard protocol in group A (n = 35) and with the activated novel dose-saving devices, OSDR and ATPS, in group B (n = 35). Objective [signal-to-noise (SNR) and contrast-to-noise ratio (CNR)] and subjective image quality (five-point scale; 1 = non diagnostic; 5 = excellent) as well as radiation dose (CTDIvol) were analysed. RESULTS: CTDIvol of the protocol using OSDR and ATPS was significantly lower than in standard chest CT examinations (3.4 ± 1 versus 6.1 ± 2.3 mGy; p < 0.001). Although the level of noise was slightly elevated in group B (14.1 ± 1.7 versus 11.4 ± 1.9 HU; p < 0.01), no significant differences in SNR (17.1 ± 5 versus 16.3 ± 4.7) or subjective image quality (mean score of 4.6 versus 4.4) were observed between both imaging protocols. CONCLUSION: Attenuation-based tube potential selection in combination with organ-specific dose reduction essentially reduces the dose of chest CT in patients with normal body mass index (BMI) in clinical routine while maintaining subjective and objective image quality.

Impact of organ-specific dose reduction on the image quality of head and neck CT angiography.

OBJECTIVES: Organ-specific dose reduction (OSDR) algorithms can reduce radiation on radiosensitive organs up to 59 %. This study evaluates the influence of a new OSDR algorithm on image quality of head and neck computed tomographic angiography (CTA) in clinical routine. METHODS: Sixty-two consecutive patients (68 ± 13 years) were randomised into two groups and imaged using 128-row multidetector CT. Group A (n = 31) underwent conventional CTA and group B (n = 31) CTA with a novel OSDR algorithm. Subjective and objective image quality were statistically compared. Subjective image quality was rated on a five-point scale. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated with region-of-interest measurements. RESULTS: The SNR of the common carotid artery and middle cerebral artery was 53.6 ± 22.7 and 43.3 ± 15.3 (group A) versus 54.1 ± 20.5 and 46.2 ± 14.6 (group B). The CNR was 40.0 ± 19.3 and 29.7 ± 12.0 (group A) compared with 40.7 ± 16.8 and 32.9 ± 10.9 (group B), respectively. Subjective image quality was excellent in both groups (mean score 4.4 ± 0.7 versus 4.4 ± 0.6). Differences between the two groups were not significant. CONCLUSIONS: The novel OSDR algorithm does not compromise image quality of head and neck CTA. Its application can be recommended for CTA in clinical routine to protect the thyroid gland and ocular lenses from unnecessary high radiation. KEY POINTS: • Organ-specific dose reduction (OSDR) can significantly reduce radiation exposure during CT • OSDR does not compromise image quality of head and neck CTA • OSDR can significantly lower the risk of radiation damage to sensitive organs • OSDR can easily be applied in routine clinical practice.

Splenic artery switch for revascularization of the liver: a salvage procedure for inflammatory arterial hemorrhage.

BACKGROUND: Hemorrhage caused by inflammatory vessel erosion represents a life-threatening complication after upper abdominal surgery such as pancreatic head resection. The gold standard therapeutic choice is an endovascular minimally invasive technique such as embolization or stent placement. Hepatic arterial hemorrhage in presence of pancreatitis and peritonitis is a particular challenge is if a standard therapeutic option is not possible. METHODS: The management of five patients with massive bleeding from the common hepatic artery is described. All patients underwent a splenic artery switch. The splenic artery was dissected close to the splenic hilum and transposed end-to-end to the common hepatic artery after resection of the eroded part. Patients' medical records, radiology reports, and images were reviewed retrospectively. Technical success was defined as immediate cessation of hemorrhage and preserved liver vascularization. Clinical success was defined as hemodynamic stability and adequate long-term liver function. RESULTS: Total pancreatectomy and splenectomy were performed in four of the five cases. Hemodynamic stability and good liver perfusion was achieved in these patients. CONCLUSIONS: Splenic artery switch is an effective, safe procedure for revascularization of the liver in case of hepatic arterial hemorrhage following pancreatic surgery, pancreatitis, and/or peritonitis. The technique is a promising option if a standard procedure-e.g., stent implantation, embolization and surgical repair with alloplastic prosthesis or autologous venous interposition graft-is not possible.

Pitfalls in radiation oncology. "Myocardial metastasis" in PET-CT after palliative radiation treatment of the left 5th rib.

BACKGROUND: Positron emission tomography-computed tomography (PET-CT) is a useful diagnostic tool to detect metastases in patients with malignancy. False positives have been reported in cases of inflammation and tissue regeneration. CASE REPORT: Over a period of 2 years, a 32-year-old woman with hepatocellular carcinoma and multiple bone metastases received three treatments of radiation therapy to a bone metastasis in the 5th left rib. Restaging with [18F]fluorodeoxyglucose (FDG) PET-CT showed increased uptake within the cardiac apex highly suspicious for a myocardial metastasis. Because the patient was asymptomatic, additional magnetic resonance imaging (MRI) of the heart was performed demonstrating radiation-associated changes but no evidence for metastases. CONCLUSION: PET-CT is a well-established diagnostic tool in metastatic diseases but its results should always be correlated with the clinical picture of the patient and previous treatments to rule out false positives.

Nonenhanced ECG-gated quiescent-interval single-shot MRA (QISS-MRA) of the lower extremities: comparison with contrast-enhanced MRA.

AIM: To evaluate electrocardiogram (ECG)-gated quiescent-interval single-shot magnetic resonance angiography (QISS-MRA) for nonenhanced assessment of peripheral artery occlusive disease (PAOD) using contrast-enhanced MRA (CE-MRA) as the reference standard. MATERIALS AND METHODS: Twenty-seven patients (mean age 66.6 ± 10.8 years) with PAOD were included in the study. QISS-MRA and CE-MRA of the lower extremity were performed using a 1.5 T MR scanner. In each patient, subjective image quality and the degree of stenosis were evaluated on a four-point scale for 15 predefined arterial segments. RESULTS: Twenty-five of the 27 patients were considered for analysis. Subjective image quality of QISS-MRA was significantly lower for the distal aorta, pelvic arteries, and femoral arteries as compared to CE-MRA (p < 0.01), while no significant difference was found for other vascular segments. The degree of stenosis was overestimated with QISS-MRA in 23 of 365 (6.3%) segments and underestimated in two of 365 (0.5%) segments. As compared to CE-MRA, QISS-MRA had a high sensitivity (98.6%), specificity (96%) as well as positive and negative predictive value (88.7 and 99.6%, respectively) for the detection of significant stenosis (≥50%). CONCLUSION: ECG-gated QISS-MRA is a promising imaging technique for reliable assessment of PAOD without the use of contrast material.

Quality indicators for the development and didactics of ultrasound courses in continuing medical education.

PURPOSE: Based on evaluation data from participant feedback, a concept was to be developed for introductory abdominal ultrasound courses lasting several days. This approach was to be developed incrementally with the intent of maximizing the learning effect per time. MATERIALS AND METHODS: This concept has been modified annually over several years based on the findings of educational research and the scores on final examinations in OSCE format. It has been modified with the aid of detailed questionnaires completed by approximately 2000 participating physicians and has thus undergone incremental optimization. RESULTS: Analysis of the most recent 1005 questionnaires has shown that participants recommend a modular course design with only brief lectures on theory (average optimal duration of 20 min., SD 9.6 min.). These should alternate with longer practical "hands-on" ultrasound exercises (60 - 90 min., accounting for at least 50 - 60 % of the course time), consolidating drawing exercises, and breaks. 51 % of the physicians specified 5 participants as the ideal group size for practical exercises, while 43 % specified only 4. The discussion presents 10 specific quality indicators for efficient ultrasound courses. It elucidates the feasibility and logistical prerequisites of this model, and compares it with other basic course concepts. Furthermore, this article presents a model for an evaluation covering the course concept and tutors as well as discussing a training program for tutors including a cost analysis. CONCLUSION: In summary, the participants estimate the course design to represent a mature concept that has demonstrated its feasibility and broad acceptance among physicians in CME.

[Polyostotic fibro-osseus lesions associated with intramuscular soft tissue neoplasms]. / Polyostotische Knochenveränderungen mit assoziierten intramuskulären Weichteiltumoren.

A 40-year-old female patient presented with progressive painful soft tissue lesions in the left upper arm. Conventional radiography showed multicystic bone tumors of the left humerus, radius and ulna. The computed tomography (CT) scan showed no paraosteal spread. Magnetic resonance imaging (MRI) detected intramuscular tumors in the deltoid muscle, biceps humeri muscle and triceps humeri muscle which were T2-weighted hyperintense and T1-weighted hypointense. Postcontrast images showed a marginal enhancement. The findings corresponded to the rare Mazabraud's syndrome in which polyostotic fibrous dysplasia is associated with intramuscular myxomas.

[Diagnosis of focal liver lesions in cirrhotic patients: comparison of contrast-enhanced ultrasound using sulphur hexafluoride (SF6) microbubbles and MRI using Gd-EOB-DTPA]. / Vergleich der kontrastverstärkten Sonografie und der MRT mit Gd-EOB-DTPA zur Diagnostik fokaler Leberläsionen bei Patienten mit Leberzirrhose.

AIM: The diagnostic accuracies of contrast-enhanced sonography and hepatobiliary contrast-enhanced MRI of the liver in evaluating focal liver lesions in patients with liver cirrhosis were compared. MATERIAL AND METHODS: In 33 patients (25 men, 8 women, mean age 63.2 ± 11.2 years) MRI of the liver using Gd-EOB-DTPA (Primovist®, Bayer Schering Pharma, Berlin) was performed. Axial T(2)-weighted, unenhanced T(1)-weighted and enhanced T(1)-weighted scans during arterial, portal venous and late phases were acquired, followed by coronary T(1)-weighted and axial fat-suppressed T(1)-weighted scans 15 minutes post contrast application. In all patients within 4 weeks contrast-enhanced sonography using sulfur hexafluoride microbubbles (SonoVue®, Nycomed, Germany) was obtained. RESULTS: Cirrhosis of the liver was related to viral infection in 45.4% and to alcoholism in 39.4%. All hepatic lesions were confirmed by histologic examination. Sensitivity and specificity of MRI were 90.2% and 83.3%, compared to contrast-enhanced sonography with 92.7 % and 50 %, respectively. Positive and negative predictive values were 97.4% and 55.5 % for MRI and 90.5% and 50% for contrast-enhanced sonography, respectively. DISCUSSION: In this retrospective study MRI using Gd-EOB-DTPA as well as contrast-enhanced sonography using sulfur hexafluoride microbubbles gave excellent results in detecting HCC in patients suffering from liver cirrhosis. Although the specificity was higher for MRI, the accuracy showed no significant difference between these two imaging techniques.

[Prevalence and clinical significance of incidental cardiac findings in non-ECG-gated chest CT scans]. / Prävalenz und klinische Bedeutung inzidenteller Herzbefunde im nicht EKG-getriggerten Thorax-CT.

BACKGROUND: The purpose of this study was to evaluate the prevalence and clinical significance of incidental cardiac findings in non-ECG-gated chest CT. PATIENTS AND METHODS: Non-ECG-gated chest CT examinations of 300 patients were retrospectively analyzed for incidental cardiac findings. Subsequently, these findings were evaluated for their clinical relevance by a cardiologist. RESULTS: A total of 107 out of 300 examined patients had 174 incidental cardiac findings including coronary calcification (90), aortic/mitral valve calcification (42), iatrogenic changes (23), pericardial effusion (6), dilatation of the heart (4), myocardial changes (3), thrombus in the left ventricle (2), constrictive pericarditis (2) and atrial myxoma (1). Of the cardiac findings 51% were described in the written report and in 53 out of the 107 patients the cardiac findings were unknown. Newly detected incidental findings from 8 patients were rated as clinically significant: pericardial effusion (4), constrictive pericarditis (1), thrombus in the left ventricle (1), atrial myxoma (1) and dilatation of the heart (1). CONCLUSION: Incidental cardiac findings are frequent in non-ECG-gated chest CT and may have a high clinical relevance.

[Case-based interactive PACS learning: introduction of a new concept for radiological education of students]. / Fallbasiertes interaktives "PACS-learning": Vorstellung eines neuen studentischen Lehrkonzepts für die Radiologie.

PURPOSE: Medical curricula are currently being reformed in order to establish superordinated learning objectives, including, e.g., diagnostic, therapeutic and preventive competences. This requires a shifting from traditional teaching methods towards interactive and case-based teaching concepts. Conceptions, initial experiences and student evaluations of a novel radiological course Co-operative Learning In Clinical Radiology (CLICR) are presented in this article. MATERIALS AND METHODS: A novel radiological teaching course (CLICR course), which combines different innovative teaching elements, was established and integrated into the medical curriculum. Radiological case vignettes were created for three clinical teaching modules. By using a PC with PACS (Picture Archiving and Communication System) access, web-based databases and the CASUS platform, a problem-oriented, case-based and independent way of learning was supported as an adjunct to the well established radiological courses and lectures. Student evaluations of the novel CLICR course and the radiological block course were compared. RESULTS: Student evaluations of the novel CLICR course were significantly better compared to the conventional radiological block course. Of the participating students 52% gave the highest rating for the novel CLICR course concerning the endpoint overall satisfaction as compared to 3% of students for the conventional block course. The innovative interactive concept of the course and the opportunity to use a web-based database were favorably accepted by the students. Of the students 95% rated the novel course concept as a substantial gain for the medical curriculum and 95% also commented that interactive working with the PACS and a web-based database (82%) promoted learning and understanding. CONCLUSION: Interactive, case-based teaching concepts such as the presented CLICR course are considered by both students and teachers as useful extensions to the radiological course program. These concepts fit well into competence-oriented curricula.

Dose Monitoring in Radiology Departments: Status Quo and Future Perspectives.

UNLABELLED: The number of computed tomography examinations has continuously increased over the last decades and accounts for a major part of the collective radiation dose from medical investigations. For purposes of quality assurance in modern radiology a systematic monitoring and analysis of dose related data from radiological examinations is mandatory. Various ways of collecting dose data are available today, for example the Digital Imaging and Communication in Medicine - Structured Report (DICOM-SR), optical character recognition and DICOM-modality performed procedure steps (MPPS). The DICOM-SR is part of the DICOM-standard and provides the DICOM-Radiation Dose Structured Report, which is an easily applicable and comprehensive solution to collect radiation dose parameters. This standard simplifies the process of data collection and enables comprehensive dose monitoring. Various commercial dose monitoring software devices with varying characteristics are available today. In this article, we discuss legal obligations, various ways to monitor dose data, current dose monitoring software solutions and future perspectives in regard to the EU Council Directive 2013/59/EURATOM. KEY POINTS: • Automated, systematic dose monitoring is an important element in quality assurance of radiology departments. • DICOM-RDSR-capable CT scanners facilitate the monitoring of dose data. • A variety of commercial and non-commercial dose monitoring software tools are available today. • Successful dose monitoring requires comprehensive infrastructure for monitoring, analysing and optimizing radiation exposure. Citation Format: • Boos J, Meineke A, Bethge OT et al. Dose Monitoring in Radiology Departments: Status Quo and Future Perspectives. Fortschr Röntgenstr 2016; 188: 443 - 450.

Cloud-Based CT Dose Monitoring using the DICOM-Structured Report: Fully Automated Analysis in Regard to National Diagnostic Reference Levels.

PURPOSE: To implement automated CT dose data monitoring using the DICOM-Structured Report (DICOM-SR) in order to monitor dose-related CT data in regard to national diagnostic reference levels (DRLs). MATERIALS AND METHODS: We used a novel in-house co-developed software tool based on the DICOM-SR to automatically monitor dose-related data from CT examinations. The DICOM-SR for each CT examination performed between 09/2011 and 03/2015 was automatically anonymized and sent from the CT scanners to a cloud server. Data was automatically analyzed in accordance with body region, patient age and corresponding DRL for volumetric computed tomography dose index (CTDIvol) and dose length product (DLP). RESULTS: Data of 36,523 examinations (131,527 scan series) performed on three different CT scanners and one PET/CT were analyzed. The overall mean CTDIvol and DLP were 51.3% and 52.8% of the national DRLs, respectively. CTDIvol and DLP reached 43.8% and 43.1% for abdominal CT (n=10,590), 66.6% and 69.6% for cranial CT (n=16,098) and 37.8% and 44.0% for chest CT (n=10,387) of the compared national DRLs, respectively. Overall, the CTDIvol exceeded national DRLs in 1.9% of the examinations, while the DLP exceeded national DRLs in 2.9% of the examinations. Between different CT protocols of the same body region, radiation exposure varied up to 50% of the DRLs. CONCLUSION: The implemented cloud-based CT dose monitoring based on the DICOM-SR enables automated benchmarking in regard to national DRLs. Overall the local dose exposure from CT reached approximately 50% of these DRLs indicating that DRL actualization as well as protocol-specific DRLs are desirable. The cloud-based approach enables multi-center dose monitoring and offers great potential to further optimize radiation exposure in radiological departments. KEY POINTS: • The newly developed software based on the DICOM-Structured Report enables large-scale cloud-based CT dose monitoring • The implemented software solution enables automated benchmarking in regard to national DRLs • The local radiation exposure from CT reached approximately 50 % of the national DRLs • The cloud-based approach offers great potential for multi-center dose analysis.

Impact of increasing levels of advanced iterative reconstruction on image quality in low-dose cardiac CT angiography.

PURPOSE: To investigate the effects of an advanced iterative reconstruction (IR) technique on subjective and objective image quality (IQ) in low-dose cardiac CT angiography (CCTA). MATERIALS AND METHODS: 30 datasets of prospectively triggered "step-and-shoot" CCTA scans acquired on a 256-slice CT scanner with optimized exposure settings were processed on a prototype IR system using filtered back-projection (FBP) and 4 levels of advanced IR (iDose4, Philips) providing incremental rates of IR (level 2, 4, 6, 7). In addition, the effects of different reconstruction kernels (semi-smooth [CB], standard with edge-enhancement [XCB]) and a "multi-resolution" feature [MR] to preserve the noise power spectrum were evaluated resulting in a total of n = 480 image sets. Contrast-to-noise ratios (CNR) were computed from regions of interest at 9 coronary locations. The subjective IQ was rated on a 4-point-scale with "classic" image appearance and noise-related artifacts as main criteria. RESULTS: At an effective dose of 1.7 ±â€Š0.7 mSv, the CNR significantly improved with every increasing level of IR (range: 14.2 - 27.8; p < 0.001) with the best objective IQ at the highest level of IR (level 7). The subjective IQ, however, was rated best at the medium level of IR (level 4) with minimal artifacts and a more "classic" image appearance when compared to higher IR levels. The XCB kernel provided better subjective ratings than CB (p < 0.05) and the MR feature further increased the IQ at a high level of IR. CONCLUSION: The objective IQ of low-dose CCTA progressively improves with an increasing level of IR. The best subjective IQ, however, is reached at medium levels of IR combined with an edge-enhancing kernel allowing for preservation of a "classic" image appearance suggesting application in the clinical routine. KEY POINTS: • iterative reconstruction (IR) improves image quality in low-dose coronary CTA• objective image quality (CNR) enhances with increasing level of IR• best subjective image quality is reached at medium level of IR• "multi-resolution" algorithm further improves image quality at a higher level of IR.

Predictive power of the ESUR scoring system for prostate cancer diagnosis verified with targeted MR-guided in-bore biopsy.

PURPOSE: This study evaluates the diagnostic value of the ESUR scoring system (PI-RADS) regarding prostate cancer detection using MR-guided in-bore biopsies (IB-GB) as the reference standard. METHODS: 566 lesions in 235 consecutive patients (65.7 ± 7.9 years, PSA 9.9 ± 8.5 ng/ml) with a multiparametric (mp)-MRI (T2WI, DWI, DCE) of the prostate at 3T were scored using the PI-RADS scoring system. PI-RADS single (PSsingle), summed (PSsum), and overall (PSoverall) scores were determined. All lesions were histologically verified by IB-GB. RESULTS: Lesions with a PSsum below 9 contained no prostate cancer (PCa) with Gleason score (GS) ≥ 4+3=7. A PSsum of 13-15 (PSoverall V) resulted in 87.8% (n=108) in PCa and in 42.3% (n=52) in GS ≥ 4+3=7. Transition zone (TZ) lesions with a PSsum of 13-15 (PSoverall V) resulted in 76.3% (n=36) in PCa and in 26.3% (n=10) in GS ≥ 4+3=7, whereas for peripheral zone (PZ) lesions cancer detection rate at this score was 92.9% (n=79) and 49.4% (n=42) for GS ≥ 4+3=7. Using a threshold of PSsum ≥ 10, sensitivity was 86.0%, and negative predictive value (NPV) was 86.2%. For higher grade PCa sensitivity was 98.6%, and NPV was 99.5%. CONCLUSION: A PSsum below 9 excluded a higher grade PCa, whereas lesions with a PSsum ≥ 13 (PSoverall V) represented in 88% PCa, and in 42% higher grade PCa. The PSsum or PSoverall demonstrated a better diagnostic value for PZ lesions with higher detection rates for higher grade PCa compared to TZ lesions.

The treatment of the acute Essex-Lopresti injury.

The Essex-Lopresti injury (ELI) of the forearm is a rare and serious condition which is often overlooked, leading to a poor outcome. The purpose of this retrospective case study was to establish whether early surgery can give good medium-term results. From a group of 295 patients with a fracture of the radial head, 12 patients were diagnosed with ELI on MRI which confirmed injury to the interosseous membrane (IOM) and ligament (IOL). They were treated by reduction and temporary Kirschner (K)-wire stabilisation of the distal radioulnar joint (DRUJ). In addition, eight patients had a radial head replacement, and two a radial head reconstruction. All patients were examined clinically and radiologically 59 months (25 to 90) after surgery when the mean Mayo Modified Wrist Score (MMWS) was 88.4 (78 to 94), the mean Mayo Elbow Performance Scores (MEPS) 86.7 (77 to 95) and the mean disabilities of arm, shoulder and hand (DASH) score 20.5 (16 to 31): all of these indicate a good outcome. In case of a high index of suspicion for ELI in patients with a radial head fracture, we recommend the following: confirmation of IOM and IOL injury with an early MRI scan; early surgery with reduction and temporary K-wire stabilisation of the DRUJ; preservation of the radial head if at all possible or replacement if not, and functional bracing in supination. This will increase the prospect of a good result, and avoid the complications of a missed diagnosis and the difficulties of late treatment.

Treatment of early and delayed esophageal perforation.

Esophageal perforations are life threatening emergencies associated with high morbidity and mortality. We report on 22 consecutive patients (age 20-86; 13 female and 9 male) with an oesophageal perforation treated at the university hospital Duesseldorf. The patients' charts were reviewed and follow-up was completed for all patients until demission, healed reconstruction or death. Patients' history, clinical presentation, time interval to surgical presentation, and treatment modality were recorded and correlated with patients' outcome. Six esophageal perforations were due to a Boerhaave-syndrome, eleven caused by endoscopic perforation, two after osteosynthesis of the cervical spine and three foreign body induced. In 7 patients a primary local suture was performed, in 4 cases a supplemental muscle flap was interposed, and 7 patients underwent an oesophageal resection. Four patients were treated without surgery (three esophageal stent implantations, one conservative treatment). Eleven patients (50 %) were presented within 24 h of perforation, and 11 patients (50 %) afterwards. Time delay correlates with survival. In 17 (80.9 %) cases a surgical sufficient reconstruction could be achieved. One (4.7 %) patient is waiting for reconstruction after esophagectomy. Four (18.2 %) patients died. A small subset of patients can be treated conservatively by stenting of the Esophagus, if the patient presents early. In the majority of patients a primary repair (muscle flap etc.) can be performed with good prognosis. If the patient presents delayed with extensive necrosis or mediastinitis, oesophagectomy and secondary repair is the only treatment option with high mortality.