How to improve image quality of DWI of the prostate-enema or catheter preparation?

OBJECTIVES: To compare the impact of laxative enema preparation versus air/gas suction through a small catheter on image quality of prostate DWI. METHODS: In this single-center study, 200 consecutive patients (100 in each arm) with either enema or catheter preparation were retrospectively included. Two blinded readers independently assessed aspects of image quality on 5-point Likert scales. Scores were compared between groups and the influence of confounding factors evaluated using multivariable logistic regression. Prostate diameters were compared on DWI and T2-weighted imaging using intraclass correlation coefficients. RESULTS: Image quality was significantly higher in the enema group regarding the severity of susceptibility-related artifacts (reader 1: 0.34 ± 0.77 vs. 1.73 ± 1.34, reader 2: 0.38 ± 0.86 vs. 1.76 ± 1.39), the differentiability of the anatomy (reader 1: 3.36 ± 1.05 vs. 2.08 ± 1.31, reader 2: 3.37 ± 1.05 vs. 2.09 ± 1.35), and the overall image quality (reader 1: 3.66 ± 0.77 vs. 2.26 ± 1.33, Reader 2: 3.59 ± 0.87 vs. 2.23 ± 1.38) with almost perfect inter-observer agreement (κ = 0.92-0.95). In the enema group, rectal distention was significantly lower and strongly correlated with the severity of artifacts (reader 1: ρ = 0.79, reader 2: ρ = 0.73). Furthermore, there were significantly fewer substantial image distortions, with odds ratios of 0.051 and 0.084 for the two readers which coincided with a higher agreement of the prostate diameters in the phase-encoding direction (0.96 vs. 0.89). CONCLUSIONS: Enema preparation is superior to catheter preparation and yields substantial improvements in image quality. KEY POINTS: • Enema preparation is superior to decompression of the rectum using air/gas suction through a small catheter. • Enema preparation markedly improves the image quality of prostate DWI regarding the severity of susceptibility-related artifacts, the differentiability of the anatomy, and the overall image quality and considerably reduces substantial artifacts that may impair a reliable diagnosis.

Addressing intimate partner violence during the COVID-19 pandemic and beyond: how radiologists can make a difference.

Faced with the COVID-19 pandemic, many countries both in Europe and across the world implemented strict stay-at-home orders. These measures helped to slow the spread of the coronavirus but also led to increased mental and physical health issues for the domestically confined population, including an increase in the occurrence of intimate partner violence (IPV) in many countries. IPV is defined as behavior that inflicts physical, psychological, or sexual harm within an intimate relationship. We believe that as radiologists, we can make a difference by being cognizant of this condition, raising an alert when appropriate and treating suspected victims with care and empathy. The aim of this Special Report is to raise awareness of IPV among radiologists and to suggest strategies by which to identify and support IPV victims. KEY POINTS: • The COVID-19 pandemic led to a marked increase in the number of intimate partner violence (IPV) cases, potentially leading to increased emergency department visits and radiological examinations. • Most IPV-related fractures affect the face, fingers, and upper trunk, and may easily be misinterpreted as routine trauma. • Radiologists should carefully review the medical history of suspicious cases, discuss the suspicion with the referring physician, and proactively engage in a private conversation with the patient, pointing to actionable resources for IPV victims.

Direct communication between radiologists and patients improves the quality of imaging reports.

OBJECTIVES: We investigate in what percentage of cases and to what extent radiological reports change when radiologists directly communicate with patients after imaging examinations. METHODS: One hundred twenty-two consecutive outpatients undergoing MRI examinations at a single center were prospectively included. Radiological reports of the patients were drafted by two radiologists in consensus using only the clinical information that was made available by the referring physicians. Thereafter, one radiologist talked directly with the patient and recorded the duration of the conversation. Afterwards, the additional information from the patient was used to reevaluate the imaging studies in consensus. The radiologists determined whether the radiological report changed based on additional information and, if yes, to what extent. The degree of change was graded on a 4-point Likert scale (1, non-relevant findings, to 4, highly relevant findings). RESULTS: Following direct communication (duration 170.9 ± 53.9 s), the radiological reports of 52 patients (42.6%) were changed. Of the 52 patients, the degree of change was classified as grade 1 for 8 patients (15.4 %), grade 2 for 27 patients (51.9%), grade 3 for 13 patients (25%), and grade 4 for 4 patients (7.7%). The reasons leading to changes were missing clinical information in 50 cases (96.2%) and the lack of additional external imaging in 2 cases (3.8%). CONCLUSIONS: Radiologists should be aware that a lack of accurate information from the clinician can lead to incorrect radiological reports or diagnosis. Radiologists should communicate directly with patients, especially when the provided information is unclear, as it may significantly alter the radiological report. KEY POINTS: • Direct communication between radiologists and patients for an average of 170's resulted in a change in the radiological reports of 52 patients (42.6%). • Of the 42.6% of cases where the reports were changed, the alterations were highly relevant (grades 3 and 4) in 32.7%, indicating major changes with significant impact towards patient management.

Intimate partner violence crisis in the COVID-19 pandemic: how can radiologists make a difference?

KEY POINTS: • The COVID-19 crisis resulted in a variety of physical and mental health issues beyond the viral infection itself, as indicated by an increase in domestic violence.• Radiologists should be aware of typical intimate partner violence (IPV) injury patterns, actively ask potential IPV victims about the cause of injury, and be familiar with support systems for IPV victims of their institutions.• Emergency and radiology departments should review their protocols for identifying and supporting IPV victims, and train their staff to work together to implement these measures during and beyond the COVID-19 crisis.

Serum albumin, total bilirubin, and patient age are independent confounders of hepatobiliary-phase gadoxetate parenchymal liver enhancement.

PURPOSE: To identify independent confounding variables of gadoxetate-enhanced hepatobiliary-phase liver MRI using multiple regression analysis. MATERIALS AND METHODS: The institutional review board generally approved retrospective analyses and all patients provided written informed consent. One hundred ten patients who underwent a standardized 3.0-T gadoxetate-enhanced liver MRI between November 2008 and June 2013 were retrospectively reviewed. The gadoxetate liver enhancement normalized to enhancement in the erector spinae muscle (relative signal enhancement, SE) was related to biochemical laboratory parameters and descriptive patient characteristics (patient age, body mass index) using non-parametric univariate correlation analysis followed by a multiple linear regression model. RESULTS: Using univariate statistics, relative SE was inversely correlated with patient age, ALP, AST, total bilirubin, gamma-glutamyltransferase, INR, model of end-stage liver disease score, and proportionally with albumin and hemoglobin (all p < 0.01). In a multiple regression analysis, total bilirubin (p = 0.001), serum albumin (p = 0.016), and patient age (p = 0.018) were independently correlated with relative liver SE (n = 110). CONCLUSION: A multiple regression analysis showed that high total bilirubin, low serum albumin, or advanced age was associated with low hepatobiliary-phase gadoxetate parenchymal liver enhancement. In these patients, the lower contrast-to-noise ratio might impair diagnostic evaluation of non-enhancing liver lesions (e.g., HCC, liver metastasis). KEY POINTS: • A multiple regression analysis identified independent confounding variables of hepatobiliary-phase gadoxetate liver enhancement. • High bilirubin, low albumin, or advanced age was associated with low enhancement. • Diagnostic evaluation might be hampered in these patients.

Direct communication between radiologists and patients following imaging examinations. Should radiologists rethink their patient care?

OBJECTIVES: To investigate patients' perception of the radiology service when the radiologist communicates the findings to patients. METHODS: After routine MRI, patients in group 1 (n = 101) were given the opportunity to discuss the findings with the radiologist. Patients in group 2 (n = 101) left the radiology department without any personal communication. Subsequently, by means of a questionnaire designed by an expert psychologist, both groups were asked regarding their anxiety, emotional attachment to the institute and subjective assessment of competence. RESULTS: Overall 76 % of all patients were concerned about their imaging findings without significant difference between both groups (p = 0.179). Significantly more patients in group 1 (81%) versus group 2 (14%; p < 0.001) perceived the opportunity to discuss their imaging findings with a radiologist to be a characteristic of a good radiology consultation. A larger number of patients in group 1 experienced significantly higher bonding and only wanted in the future to be examined in the department with communication (p = 0.001) (93%/75%). Significantly more patients in group 1 regarded the radiology department they attended as being more competent (mean score 4.72/4.09, p < 0.001). CONCLUSION: Direct communication of imaging findings from radiologists to patients after an MRI examination leads to increased confidence in the radiology service and higher bonding between the patient and radiologist. Radiologists who refrain from direct communication have a lower bonding to patients and are assessed to have lower competence from the patient's point of view. KEY POINTS: • Communication between radiologists and patients leads to an increased bonding affinity. • Direct communication leads to increased patient confidence in the radiology service. • Patients perceived discussion with a radiologist of high value.

Would it be safe to have a dog in the MRI scanner before your own examination? A multicenter study to establish hygiene facts related to dogs and men.

OBJECTIVES: To determine whether it would be hygienic to evaluate dogs and humans in the same MRI scanner. METHODS: We compared the bacterial load in colony-forming units (CFU) of human-pathogenic microorganisms in specimens taken from 18 men and 30 dogs. In addition, we compared the extent of bacterial contamination of an MRI scanner shared by dogs and humans with two other MRI scanners used exclusively by humans. RESULTS: Our study shows a significantly higher bacterial load in specimens taken from men's beards compared with dogs' fur (p = 0.036). All of the men (18/18) showed high microbial counts, whereas only 23/30 dogs had high microbial counts and 7 dogs moderate microbial counts. Furthermore, human-pathogenic microorganisms were more frequently found in human beards (7/18) than in dog fur (4/30), although this difference did not reach statistical significance (p = 0.074). More microbes were found in human oral cavities than in dog oral cavities (p < 0.001). After MRI of dogs, routine scanner disinfection was undertaken and the CFU found in specimens isolated from the MRI scanning table and receiver coils showed significantly lower bacteria count compared with "human" MRI scanners (p < 0.05). CONCLUSION: Our study shows that bearded men harbour significantly higher burden of microbes and more human-pathogenic strains than dogs. As the MRI scanner used for both dogs and humans was routinely cleaned after animal scanning, there was substantially lower bacterial load compared with scanners used exclusively for humans. KEY POINTS: • Bearded men harbour significantly more microbes than dogs. • Dogs are no risk to humans if they use the same MRI. • Deficits in hospital hygiene are a relevant risk for patients.

Gadolinium Distribution in Cerebrospinal Fluid after Administration of a Gadolinium-based MR Contrast Agent in Humans.

Purpose To evaluate whether gadolinium penetrates human cerebrospinal fluid (CSF) after MR imaging (MRI) with a gadolinium-based contrast agent (GBCA). Materials and Methods For this retrospective study, the authors analyzed 60 CSF samples from 57 patients (median age, 50 years; range, 3-92 years) who underwent one contrast material-enhanced MRI examination with gadoterate meglumine within 60 days of CSF extraction between January and December 2016. CSF samples from patients who underwent MRI without contrast material administration (n = 22) or those who underwent contrast-enhanced MRI at least 1 year before extraction (n = 2) were analyzed and used as control samples. CSF measurements were performed with inductively coupled plasma mass spectrometry by monitoring the gadolinium 158 isotope. Statistical analyses were performed by using a preliminary Kruskal-Wallis test. Results Higher CSF gadolinium concentrations were detected within the first 8 hours after GBCA administration (mean concentration, 1152 ng/mL ± 734.6). Concentrations were lower between 8 and 48 hours (872 ng/mL ± 586). After 48 hours, gadolinium was almost completely cleared from CSF (121 ng/mL ± 296.3). All but two samples from the 24 control patients (median age, 60.5 years; range, 19-79 years) were negative for the presence of gadolinium. Those samples were from patients who had undergone GBCA-enhanced MRI examination more than a year before CSF extraction (0.1 and 0.2 ng/mL after 1 and 3 years, respectively). The concentrations in patients with chronic renal insufficiency (n = 3), cerebral toxoplasmosis (n = 1), and liver cirrhosis (n = 1) were higher than the mean concentrations. Conclusion Gadoterate meglumine can be detected in human CSF after intravenous administration.

Functional and Targeted Lymph Node Imaging in Prostate Cancer: Current Status and Future Challenges.

Patients with prostate cancer who have regional lymph node (LN) metastases face an increased risk of death from disease and are therefore treated aggressively. Surgical LN dissection is the established method of staging regional nodes; however, this invasive technique carries substantial morbidities and a noninvasive imaging method is needed to reduce or eliminate the need for extended pelvic LN dissections (ePLND). Conventional computed tomography and magnetic resonance (MR) imaging have proven insensitive and nonspecific because both use nodal size criteria, which is notoriously inaccurate. Novel imaging techniques such as functional MR imaging by using diffusion-weighted MR imaging, MR lymphography with iron oxide particles, and targeted positron emission tomography imaging are currently under development and appear to improve LN staging of prostate cancer. Although progress is being made in staging nodes with imaging, it has not reached the point of replacing ePLND. In this review, the strengths and limitations of these new functional and targeted LN imaging techniques for prostate cancer are discussed. © RSNA, 2017.

Comparison of Intravoxel Incoherent Motion Parameters across MR Imagers and Field Strengths: Evaluation in Upper Abdominal Organs.

Purpose To determine the reproducibility of intravoxel incoherent motion (IVIM) parameters measured in upper abdominal organs with magnetic resonance (MR) imagers from different vendors and with different field strengths. Materials and Methods This prospective study was approved by the independent ethics committees of Kanton Bern and Kanton Zurich, and signed informed consent was obtained from all participants. Abdominal diffusion-weighted images in 10 healthy men (mean age, 37 years ± 8 [standard deviation]) were acquired by using 1.5- and 3.0-T MR imagers from three different vendors. Two readers independently delineated regions of interest that were used to measure IVIM parameters (diffusion coefficient [Dt], perfusion fraction [Fp], and pseudodiffusion coefficient [Dp]) in the left and right lobes of the liver, and in the pancreas, spleen, renal cortex, and renal medulla. Measurement reproducibility between readers was assessed with intraclass correlation coefficients (ICCs). Variability across MR imagers was analyzed by using between- and within-subject coefficients of variation (CVs) and analysis of variance (ANOVA). Results Between-reader reproducibility was high for Dt (ICC, 94.6%), intermediate for Fp (ICC, 81.7%), and low for Dp (ICC, 69.5%). Between- and within-subject CVs of Dt were relatively high (>20%) in the left lobe of the liver and relatively low (<10%) in the renal cortex and renal medulla. CVs generally exceeded 15% for Fp values and 20% for Dp. ANOVA indicated significant differences (P < .05) between MR imagers. Conclusion IVIM parameters in the upper abdomen may differ substantially across MR imagers. (©) RSNA, 2015 Online supplemental material is available for this article.

Impact of the calculation algorithm on biexponential fitting of diffusion-weighted MRI in upper abdominal organs.

PURPOSE: To compare the variability, precision, and accuracy of six different algorithms (Levenberg-Marquardt, Trust-Region, Fixed-Dp , Segmented-Unconstrained, Segmented-Constrained, and Bayesian-Probability) for computing intravoxel-incoherent-motion-related parameters in upper abdominal organs. METHODS: Following the acquisition of abdominal diffusion-weighted magnetic resonance images of 10 healthy men, six distinct algorithms were employed to compute intravoxel-incoherent-motion-related parameters in the left and right liver lobe, pancreas, spleen, renal cortex, and renal medulla. Algorithms were evaluated regarding inter-reader and intersubject variability. Comparability of results was assessed by analyses of variance. The algorithms' precision and accuracy were investigated on simulated data. RESULTS: A Bayesian-Probability based approach was associated with very low inter-reader variability (average Intraclass Correlation Coefficients: 96.5-99.6%), the lowest inter-subject variability (Coefficients of Variation [CV] for the pure diffusion coefficient Dt : 3.8% in the renal medulla, 6.6% in the renal cortex, 10.4-12.1% in the left and right liver lobe, 15.3% in the spleen, 15.8% in the pancreas; for the perfusion fraction Fp : 15.5% on average; for the pseudodiffusion coefficient Dp : 25.8% on average), and the highest precision and accuracy. Results differed significantly (P < 0.05) across algorithms in all anatomical regions. CONCLUSION: The Bayesian-Probability algorithm should be preferred when computing intravoxel-incoherent-motion-related parameters in upper abdominal organs.

Pilot study on the detection of antiandrogen resistance using serial diffusion-weighted imaging of bone metastases in prostate cancer.

PURPOSE: To evaluate serial apparent diffusion coefficient (ADC) measurements of bone metastases in prostate cancer to determine whether antiandrogen resistance can be detected and time to progression estimated. MATERIALS AND METHODS: Diffusion-weighted imaging (DWI) was performed at 1.5T in nine patients with treatment-naïve metastatic prostate cancer (20 lesions) before antiandrogen treatment, after 1, 2, and 3 months of treatment, and thereafter every 4 months over 31 months or until antiandrogen resistance was detected. Tumor volumes were stable over time. Time courses of the ADCs when averaged over entire lesions and on functional diffusion maps (fDMs) were analyzed using marginal linear model (MLM) analysis. RESULTS: Starting at 1 month, MLM analysis revealed decreasing mean ADCs (P = 0.001) over time. Simultaneously, the percentage of voxels with significantly higher ADCs decreased (P = 0.004), whereas the percentage of voxels with significantly lower ADCs increased (P < 0.001) on fDMs. Both mean ADCs (P = 0.042) and percentages of voxels with significantly higher ADCs on fDMs (P = 0.039) decreased more rapidly over time in patients with a shorter progression-free interval (PFI). Likewise, higher (P = 0.001) and more rapidly increasing (P = 0.002) percentages of voxels with significantly lower ADCs on fDMs were associated with a shorter PFI. CONCLUSION: The results of our pilot study suggest that the evolution of ADCs over time may permit early identification of antiandrogen resistance in bone metastases. J. Magn. Reson. Imaging 2016;43:1407-1416.

Age dependence of spleen- and muscle-corrected hepatic signal enhancement on hepatobiliary phase gadoxetate MRI.

OBJECTIVES: To identify correlations of signal enhancements (SE) and SE normalized to reference tissues of the spleen, kidney, liver, musculus erector spinae (MES) and ductus hepatocholedochus (DHC) on hepatobiliary phase gadoxetate-enhanced MRI with patient age in non-cirrhotic patients. METHODS: A heterogeneous cohort of 131 patients with different clinical backgrounds underwent a standardized 3.0-T gadoxetate-enhanced liver MRI between November 2008 and June 2013. After exclusion of cirrhotic patients, a cohort of 75 patients with no diagnosed diffuse liver disease was selected. The ratio of signal intensity 20 min post- to pre-contrast administration (SE) in the spleen, kidney, liver, MES and DHC, and the SE of the kidney, liver and DHC normalized to the reference tissues spleen or MES were compared to patient age. RESULTS: Patient age was inversely correlated with the liver SE normalized to the spleen and MES SE (both p < 0.001) and proportionally with the SE of the spleen (p = 0.043), the MES (p = 0.030) and the kidney (p = 0.022). No significant correlations were observed for the DHC (p = 0.347) and liver SE (p = 0.606). CONCLUSION: The age dependence of hepatic SE normalized to the enhancement in the spleen and MES calls for a cautious interpretation of these quantification methods. KEY POINTS: • Patient age was inversely correlated with spleen- and MES-corrected liver rSE (p < 0.001). • Patient age was correlated with spleen (p = 0.043) and MES SE (p = 0.030). • Patient age may confound quantitative liver function assessment using gadoxetate-enhanced liver MRI.

Reduction in respiratory motion artefacts on gadoxetate-enhanced MRI after training technicians to apply a simple and more patient-adapted breathing command.

OBJECTIVE: To investigate whether a trained group of technicians using a modified breathing command during gadoxetate-enhanced liver MRI reduces respiratory motion artefacts compared to non-trained technicians using a traditional breathing command. MATERIALS AND METHODS: The gadoxetate-enhanced liver MR images of 30 patients acquired using the traditional breathing command and the subsequent 30 patients after training the technicians to use a modified breathing command were analyzed. A subgroup of patients (n = 8) underwent scans both by trained and untrained technicians. Images obtained using the traditional and modified breathing command were compared for the presence of breathing artefacts [respiratory artefact-based image quality scores from 1 (best) to 5 (non-diagnostic)]. RESULTS: There was a highly significant improvement in the arterial phase image quality scores in patients using the modified breathing command compared to the traditional one (P < 0.001). The percentage of patients with severe and extensive breathing artefacts in the arterial phase decreased from 33.3 % to 6.7 % after introducing the modified breathing command (P = 0.021). In the subgroup that underwent MRI using both breathing commands, arterial phase image quality improved significantly (P = 0.008) using the modified breathing command. CONCLUSION: Training technicians to use a modified breathing command significantly improved arterial phase image quality of gadoxetate-enhanced liver MRI. KEY POINTS: • A modified breathing command reduced respiratory artefacts on arterial-phase gadoxetate-enhanced MRI (P < 0.001). • The modified command decreased severe and extensive arterial-phase breathing artefacts (P = 0.021). • Training technicians to use a modified breathing command improved arterial-phase images.

Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study.

OBJECTIVE: Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. MATERIAL AND METHODS: The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. RESULTS: Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. CONCLUSION: Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. KEY POINTS: • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers.

PET/MRI and PET/CT in advanced gynaecological tumours: initial experience and comparison.

PURPOSE: To compare the diagnostic accuracy of PET/MRI and PET/CT for staging and re-staging advanced gynaecological cancer patients as well as identify the potential benefits of each method in such a population. MATERIAL AND METHODS: Twenty-six patients with suspicious or proven advanced gynaecological cancer (12 ovarian, seven cervical, one vulvar and four endometrial tumours, one uterine metastasis, and one primary peritoneal cancer) underwent whole-body imaging with a sequential trimodality PET/CT/MR system. Images were analysed regarding primary tumour detection and delineation, loco-regional lymph node staging, and abdominal/extra-abdominal distant metastasis detection (last only by PET/CT). RESULTS: Eighteen (69.2 %) patients underwent PET/MRI for primary staging and eight patients (30.8 %) for re-staging their gynaecological malignancies. For primary tumour delineation, PET/MRI accuracy was statistically superior to PET/CT (p < 0.001). Among the different types of cancer, PET/MRI presented better tumour delineation mainly for cervical (6/7) and endometrial (2/3) cancers. PET/MRI for local evaluation as well as PET/CT for extra-abdominal metastases had therapeutic consequences in three and one patients, respectively. PET/CT detected 12 extra-abdominal distant metastases in 26 patients. CONCLUSION: PET/MRI is superior to PET/CT for primary tumour delineation. No differences were found in detection of regional lymph node involvement and abdominal metastases detection. KEY POINTS: • PET/MRI is superior to PET/CT for primary tumour delineation • PET/CT represents a reliable tool to detect extra-abdominal distant metastasis • PET/MRI might be the preferred imaging modality for staging cervical and endometrial tumours • Whole-body staging for detection and evaluation of extra-abdominal metastases is mandatory.

Fairly direct hit! Advances in imaging of shotgun projectiles in MRI.

OBJECTIVES: To investigate the magnetic properties of different types of projectiles and qualify the metal artefact reduction technique for diagnostic and/or forensic MRI. MATERIALS AND METHODS: Ten different projectiles embedded in ordnance gelatine blocks underwent an in vitro 1.5-T MR study with seven sequences including a recently developed metal artefact reduction sequence (Advanced WARP) combining VAT (view-angle-tilting) and SEMAC (slice-encoding metal-artefact-correction). Resulting image quality (five-point scale: 1=best; 5=worst) was scored. Quantifiable magnetic characteristics were correlated with qualitative rating of the MR sequences and torque dislodgment. RESULTS: Metal artefact reduction sequence (median: 2.5) significantly (p < 0.001) improves depiction of projectiles in comparison to all other MR pulse sequences (median: 4.75). Images from diamagnetic composed bullets (median: 2) are much less disturbed compared to magnetic attracted ones (median: 5). Correlation (0.623) between deflection angle measurement (ferromagnetic mean 84.2°; paramagnetic 62°; diamagnetic mean 0°) and median qualitative image quality was highly significant (p = 0.027). Torque dislodgement was distinct for elongated magnetic attracted projectiles. CONCLUSIONS: Significant improvement of MR imaging of projectiles using metal artefact reduction techniques has important implications for diagnostic/forensic work-up. The correlations between magnetic attraction force, deflection-angle results and image properties demonstrate that the MR safety of projectiles can be estimated with one of these methods. KEY POINTS: • Metal artefact reduction sequence improves overall image quality of bullets (p < 0.001). • Deflection angle assessment significantly predicts image quality of bullets (p = 0.027). • Classification of projectiles' magnetic properties based on artefacts' characteristics is possible. • Classifying of bullets has important implications in diagnostic and forensic imaging. • Identification of projectiles' magnetic attributes improves estimation of patients' injury risk.