Quantification of Liver Iron Overload with MRI: Review and Guidelines from the ESGAR and SAR.

Accumulation of excess iron in the body, or systemic iron overload, results from a variety of causes. The concentration of iron in the liver is linearly related to the total body iron stores and, for this reason, quantification of liver iron concentration (LIC) is widely regarded as the best surrogate to assess total body iron. Historically assessed using biopsy, there is a clear need for noninvasive quantitative imaging biomarkers of LIC. MRI is highly sensitive to the presence of tissue iron and has been increasingly adopted as a noninvasive alternative to biopsy for detection, severity grading, and treatment monitoring in patients with known or suspected iron overload. Multiple MRI strategies have been developed in the past 2 decades, based on both gradient-echo and spin-echo imaging, including signal intensity ratio and relaxometry strategies. However, there is a general lack of consensus regarding the appropriate use of these methods. The overall goal of this article is to summarize the current state of the art in the clinical use of MRI to quantify liver iron content and to assess the overall level of evidence of these various methods. Based on this summary, expert consensus panel recommendations on best practices for MRI-based quantification of liver iron are provided.

Indexing Imaging Reports for Data Sharing: A Study of Mapping Using RadLex Playbook and LOINC.

New use cases and the need for quality control and imaging data sharing in health studies require the capacity to align them to reference terminologies. We are interested in mapping the local terminology used at our center to describe imaging procedures to reference terminologies for imaging procedures (RadLex Playbook and LOINC/RSNA Radiology Playbook). We performed a manual mapping of the 200 most frequent imaging report titles at our center (i.e. 73.2% of all imaging exams). The mapping method was based only on information explicitly stated in the titles. The results showed 57.5% and 68.8% of exact mapping to the RadLex and LOINC/RSNA Radiology Playbooks, respectively. We identified the reasons for the mapping failure and analyzed the issues encountered.

Proton pump inhibition for secondary hemochromatosis in hereditary anemia: a phase III placebo-controlled randomized cross-over clinical trial.

Iron overload is a severe general complication of hereditary anemias. Treatment with iron chelators is hampered by important side-effects, high costs, and the lack of availability in many countries with a high prevalence of hereditary anemias. In this phase III randomized placebo-controlled trial, we assigned adults with non-transfusion-dependent hereditary anemias with mild-to-moderate iron overload to receive esomeprazole (at a dose of 40 mg twice daily) or placebo for 12 months in a cross-over design. The primary end point was change of liver iron content measured by MRI. A total of 30 participants were enrolled in the trial. Treatment with esomeprazole resulted in a statistically significant reduction in liver iron content that was 0.55 mg Fe/g dw larger than after treatment with placebo (95%CI [0.05 to 1.06]; p = 0.03). Median baseline liver iron content at the start of esomeprazole was 4.99 versus 4.49 mg Fe/g dw at start of placebo. Mean delta liver iron content after esomeprazole treatment was -0.57 (SD 1.20) versus -0.11 mg Fe/g dw (SD 0.75) after placebo treatment. Esomeprazole was well tolerated, reported adverse events were mild and none of the patients withdrew from the study due to side effects. In summary, esomeprazole resulted in a significant reduction in liver iron content when compared to placebo in a heterogeneous group of patients with non-transfusion-dependent hereditary anemias. From an international perspective this result can have major implications given the fact that proton pump inhibitors may frequently be the only realistic therapy for many patients without access to or not tolerating iron chelators.

Practical guide to quantification of hepatic iron with MRI.

Our intention is to demystify the MR quantification of hepatic iron (i.e., the liver iron concentration) and give you a step-by-step approach by answering the most pertinent questions. The following article should be more of a manual or guide for every radiologist than a classic review article, which just summarizes the literature. Furthermore, we provide important background information for professional communication with clinicians. The information regarding the physical background is reduced to a minimum. After reading this article, you should be able to perform adequate MR measurements of the LIC with 1.5-T or 3.0-T scanners. KEY POINTS: • MRI is widely accepted as the primary approach to non-invasively determine liver iron concentration (LIC). • This article is a guide for every radiologist to perform adequate MR measurements of the LIC. • When using R2* relaxometry, some points have to be considered to obtain correct measurements-all explained in this article.

Whole-Body CT after Motor Vehicle Crash: No Benefit after High-Energy Impact and with Normal Physical Examination.

Background Debate continues about the risks and benefits of systematic whole-body CT when no injury is clinically suspected. Risks of whole-body CT include high radiation exposure and iodine contrast agent, but its effectiveness in reducing mortality in low-risk motor vehicle crashes is unclear. Purpose To assess unsuspected injuries revealed at whole-body CT in patients following motor vehicle crash (MVC) meeting only kinetic elements of the Vittel criteria for the severity of trauma, with no evidence of trunk injury and a Glasgow Coma Scale score of 15. Materials and Methods This retrospective study included all consecutive adult patients who consulted an emergency department of a level 1 trauma center between August 2016 and July 2017 if they underwent whole-body CT for one or more kinetic elements of the Vittel criteria, had a normal examination of the trunk, and had a Glasgow Coma Scale score of 15. Data of the MVC mechanism and physical and biologic examinations were collected, as well as patient treatment data after whole-body CT. Whole-body CT examinations were read by two double-blinded readers to help detect unsuspected injuries. Results Ninety-three patients were included; 72 were men with a mean age of 30.8 years ± 12.0 (standard deviation). Sixty-nine patients were occupants of a car. Seventeen patients were hit by a car while on motorbikes, three while on bicycles, and four as pedestrians. Unsuspected injuries were depicted at 11 whole-body CT examinations: eight lung contusions, one acetabular fracture, one sternal fracture, and one adrenal hematoma. None of these injuries required a specific treatment. One patient with lung contusion of more than 30% of lung volume was followed without requiring further treatment. Conclusion In this population, whole-body CT did not lead to any change in patient treatment. These results suggest whole-body CT should not be systematically performed when no evidence of trunk injury is observed in patients following motor vehicle crash meeting only kinetic elements of Vittel criteria. © RSNA, 2019 See also the editorial by Munera and Durso in this issue.

Non-invasive measurement of liver iron concentration using 3-Tesla magnetic resonance imaging: validation against biopsy.

OBJECTIVES: To evaluate the performance and limitations of the R2* and signal intensity ratio (SIR) methods for quantifying liver iron concentration (LIC) at 3 T. METHODS: A total of 105 patients who underwent a liver biopsy with biochemical LIC (LICb) were included prospectively. All patients underwent a 3-T MRI scan with a breath-hold multiple-echo gradient-echo sequence (mGRE). LIC calculated by 3-T SIR algorithm (LICSIR) and by R2* (LICR2*) were correlated with LICb. Sensitivity and specificity were calculated. The comparison of methods was analysed for successive classes. RESULTS: LICb was strongly correlated with R2* (r = 0.95, p < 0.001) and LICSIR (r = 0.92, p < 0.001). In comparison to LICb, LICR2* and LICSIR detect liver iron overload with a sensitivity/specificity of 0.96/0.93 and 0.92/0.95, respectively, and a bias ± SD of 7.6 ± 73.4 and 14.8 ± 37.6 µmol/g, respectively. LICR2* presented the lowest differences for patients with LICb values under 130 µmol/g. Above this value, LICSIR has the lowest differences. CONCLUSIONS: At 3 T, R2* provides precise LIC quantification for lower overload but the SIR method is recommended to overcome R2* limitations in higher overload. Our software, available at www.mrquantif.org , uses both methods jointly and selects the best one. KEY POINTS: • Liver iron can be accurately quantified by MRI at 3 T • At 3 T, R2* provides precise quantification of slight liver iron overload • At 3 T, SIR method is recommended in case of high iron overload • Slight liver iron overload present in metabolic syndrome can be depicted • Treatment can be monitored with great confidence.

MRI for the measurement of liver iron content, and for the diagnosis and follow-up of iron overload disorders.

MRI is now the reference method for detecting and quantifying hepatic and extrahepatic iron overload, regardless of its cause. The decrease of the hepatic signal is proportional to the amount of iron in the tissues. It is more pronounced with T2*-weighted gradient echo sequences. It increases proportionally with the strength of the magnetic field. Thus a 3-T MRI is be more sensitive and probably more accurate to detect a slight iron overload, as seen in dysmetabolic hepatosiderosis. Conversely, a 1.5-T MRI better estimates a high overload. Quantification can be done with the calculation of T2* (or R2*) or by using the liver to muscle signal intensity ratio (SIR). Today with a single multi-echo gradient-echo sequence, obtained in a unique apnea, the two methods can be used simultaneously. An associated quantification of steatosis is also obtained. This same type of sequence is proposed for quantification of iron in other tissues and in particular for the myocardium.

Comparison of Choi criteria and Response Evaluation Criteria in Solid Tumors (RECIST) for intrahepatic cholangiocarcinoma treated with glass-microspheres Yttrium-90 selective internal radiation therapy (SIRT).

OBJECTIVE: To compare Choi criteria with Response Evaluation Criteria in Solid Tumors (RECIST) for the prediction of overall survival (OS) in patients treated with glass-microspheres, Yttrium-90 selective internal radiation therapy (SIRT) for intrahepatic cholangiocarcinoma (ICC). METHODS: Between 2010 and 2014, 45 adult patients with locally advanced ICC treated with SIRT were retrospectively analyzed. Computed tomography scans performed before and after treatment were analyzed using both RECIST 1.1 and Choi criteria. Response was correlated with survival. RESULTS: Patients who achieved an objective response according to Choi had a longer OS than non-responders (median OS 19.9 months [95% CI, 1.1-38.7 months] vs. 7.5 months if stable disease [uncountable CI] and 3 months if progressive disease [95% CI, 0-6.2 months], log-rank test: p=0.003) whereas there was no significant survival difference according to the RECIST response (p=0.339). Among the 39 RECIST non-responding patients, those identified as responders by Choi (n=31) had significantly better OS than Choi non-responders (median OS 19.9 months (95% CI, 5.1-34.7 months) and 5.4 months (95% CI, 0-11.6 months), p=0.005). CONCLUSIONS: Choi criteria appear more appropriate than RECIST to identify responders with long survival among patients who received SIRT for ICC.

Acoustic radiation force impulse imaging for assessing liver fibrosis in alcoholic liver disease.

AIM: To evaluate the performance of elastography by ultrasound with acoustic radiation force impulse (ARFI) in determining fibrosis stage in patients with alcoholic liver disease (ALD) undergoing alcoholic detoxification in relation to biopsy. METHODS: Eighty-three patients with ALD undergoing detoxification were prospectively enrolled. Each patient underwent ARFI imaging and a liver biopsy on the same day. Fibrosis was staged according to the METAVIR scoring system. The median of 10 valid ARFI measurements was calculated for each patient. RESULTS: Sixty-nine males and thirteen females (one patient excluded due to insufficient biopsy size) were assessed with a mean alcohol consumption of 132.4 ± 128.8 standard drinks per week and mean cumulative year duration of 17.6 ± 9.5 years. Sensitivity and specificity were respectively 82.4% (0.70-0.95) and 83.3% (0.73-0.94) (AUROC = 0.87) for F ≥ 2 with a cut-off value of 1.63m/s; 82.4% (0.64-1.00) and 78.5% (0.69-0.89) (AUROC = 0.86) for F ≥ 3 with a cut-off value of 1.84m/s; and 92.3% (0.78-1.00] and 81.6% (0.72-0.90) (AUROC = 0.89) for F = 4 with a cut-off value of 1.94 m/s. CONCLUSION: ARFI is an accurate, non-invasive and easy method for assessing liver fibrosis in patients with ALD undergoing alcoholic detoxification.

Dynamic contrast-enhanced MRI: Study of inter-software accuracy and reproducibility using simulated and clinical data.

PURPOSE: To test the reproducibility and accuracy of pharmacokinetic parameter measurements on five analysis software packages (SPs) for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), using simulated and clinical data. MATERIALS AND METHODS: This retrospective study was Institutional Review Board-approved. Simulated tissues consisted of pixel clusters of calculated dynamic signal changes for combinations of Tofts model pharmacokinetic parameters (volume transfer constant [K(trans) ], extravascular extracellular volume fraction [ve ]), longitudinal relaxation time (T1 ). The clinical group comprised 27 patients treated for rectal cancer, with 36 3T DCE-MR scans performed between November 2012 and February 2014, including dual-flip-angle T1 mapping and a dynamic postcontrast T1 -weighted, 3D spoiled gradient-echo sequence. The clinical and simulated images were postprocessed with five SPs to measure K(trans) , ve , and the initial area under the gadolinium curve (iAUGC). Modified Bland-Altman analysis was conducted, intraclass correlation coefficients (ICCs) and within-subject coefficients of variation were calculated. RESULTS: Thirty-one examinations from 23 patients were of sufficient technical quality and postprocessed. Measurement errors were observed on the simulated data for all the pharmacokinetic parameters and SPs, with a bias ranging from -0.19 min(-1) to 0.09 min(-1) for K(trans) , -0.15 to 0.01 for ve , and -0.65 to 1.66 mmol.L(-1) .min for iAUGC. The ICC between SPs revealed moderate agreement for the simulated data (K(trans) : 0.50; ve : 0.67; iAUGC: 0.77) and very poor agreement for the clinical data (K(trans) : 0.10; ve : 0.16; iAUGC: 0.21). CONCLUSION: Significant errors were found in the calculated DCE-MRI pharmacokinetic parameters for the perfusion analysis SPs, resulting in poor inter-software reproducibility. J. Magn. Reson. Imaging 2016;43:1288-1300.

The effect of water suppression on the hepatic lipid quantification, as assessed by the LCModel, in a preclinical and clinical scenario.

OBJECTIVE: To investigate the effect of water suppression on the hepatic lipid quantification, using the LCModel. MATERIALS AND METHODS: MR spectra with and without water suppression were acquired in the liver of mice at 4.7 T and patients at 3 T, and processed with the LCModel. The Cramér-Rao Lower Bound (CRLB) values of the seven lipid resonances were determined to assess the impact of water suppression on hepatic lipid quantification. A paired t test was used for comparison between the CRLBs obtained with and without water suppression. RESULTS: For the preclinical data, in the high (low) fat fraction subset an overall impairment in hepatic lipid quantification, i.e. an increase of CRLBs (no significant change of CRLBs) was observed in spectra acquired with water suppression. For the clinical data, there were no substantial changes in the CRLB with water suppression. Because (1) the water suppression does not overall improve the quantification of the lipid resonances and (2) the MR spectrum without water suppression is always acquired for fat fraction calculation, the optimal data-acquisition strategy for liver MRS is to acquire only the MR spectrum without water suppression. CONCLUSION: For quantification of hepatic lipid resonances, it is advantageous to perform MR spectroscopy without water suppression in a clinical and preclinical scenario (at moderate fields).

A simple system to predict perihilar cholangiocarcinoma resectability.

BACKGROUND: The aim of this study was to retrospectively validate a new system to predict perihilar cholangiocarcinoma (PHC) resectability. We hypothesized that when the left lateral section (segments II-III) duct confluence (LLC) is free, the left lateral section might be preserved for curative resection. When the LLC is invaded, vascular invasion is frequent and radical resection might often be impossible without complex vascular reconstruction. METHOD: Radiological files of patients operated for PHC at our institution were reviewed and PHC was classified depending on whether LLC was invaded (type X) or free (type Y). Peroperative findings and follow-up were then matched with our XY classification. RESULTS: Thirty-seven patients were included, 28 (78 %) type Y and nine (22 %) type X PHCs. Hepatic artery (HA) invasion was present in 14 % of type Y and 100 % of type X PHCs (P < 0.001). Left HA was never involved in type Y and always involved in type X. Portal vein invasion was present in 25 and 78 % of type Y and type X PHC, respectively (P = 0.014). Complete resection rates without HA in type Y and X patients were 89 % (84 % R0 and 16 % R1) and 33 % (37.5 % R0 and 12.5 % R1), respectively (P = 0.01). Sensitivity, specificity, and precision of the XY classification to predict resectability were 84, 67, and 84 %, respectively. CONCLUSION: XY classification for PHCs suggests that in type Y (free LLC), the tumor is most often resectable, while in type X (LLC involved), the tumor is only resectable using complex vascular reconstructions.

Localized hypertrophic neuropathy of the sciatic nerve in children: MRI findings.

BACKGROUND: Localized hypertrophic neuropathy (LHN) of the sciatic nerve in children is a rare condition characterized by a painless neurological deficit in the sciatic nerve territory. OBJECTIVE: To demonstrate the role of MRI using a specific protocol and describe the primary findings in LHN. MATERIALS AND METHODS: Imaging in four children (age 2 years to 12 years) is presented. All children presented with lower limb asymmetry. Three had a steppage gait. LHN was confirmed by electrophysiological studies and by MRI of the whole sciatic nerve with a dedicated protocol covering the lumbar spine and the lower limb. RESULTS: There were four direct MRI findings: (1) linear and focal hypertrophy with progressive enlargement of a peripheral nerve or plexus diameter, (2) abnormal hyperintensity of the nerve on T2-weighted images, (3) preserved fascicular configuration, and (4) variable enhancement after intravenous gadolinium administration. In addition there were atrophy and fatty infiltration of innervated muscles. MRI was helpful for determining the extent of lesions and in excluding peripheral nerve compression or tumour. CONCLUSION: MRI of the whole sciatic nerve is the method of choice for diagnosing LHN of the sciatic nerve.

MRI quantification of splenic iron concentration in mouse.

PURPOSE: To quantify hepatic and splenic iron load, which is a critical issue for iron overload disease diagnosis. MRI is useful to noninvasively determine liver iron concentration, but not proven to be adequate for robust evaluation of splenic iron load. We evaluated the usefulness of MRI-derived parameters to determine splenic iron concentration in mice. MATERIALS AND METHODS: A mouse model of experimental iron load was used. Multi-echo spin-echo images of liver and spleen were acquired at 4.7 Tesla. The parameters were tested at all echoes with and without an external reference. Splenic and hepatic iron concentrations were determined using biochemical assay as the gold standard. RESULTS: Our results show that (i) use of an internal or external reference is essential; (ii) optimal echo times were TE = 19.5 ms and TE = 32.5 ms for the liver and spleen, respectively; (iii) in the liver, the relationship between biochemical and MRI iron concentration determinations is logarithmic; (iv) in the spleen, the best relationship is an inverse function. CONCLUSION: A single spin-echo sequence allows robust estimation of hepatic and splenic iron content. Parameters classically used for hepatic iron concentration cannot be applied to splenic iron determination, which requires both the specific sequence and the adapted fitting function.

Assessment of water enema computed tomography: an effective imaging technique for the diagnosis of colon cancer: Colon cancer: computed tomography using a water enema.

AIM: The aim of this study was to assess the accuracy of water enema computed tomography (WECT) for the diagnosis of colon cancer. METHODS: A total of 191 patients referred for clinically suspected colon cancer were prospectively evaluated by WECT in a multicenter trial. Examination was contrast enhanced helical CT after colon filling through a rectal tube. For all the cases, final diagnosis was obtained by colonoscopy and/or surgery. CT data were interpreted both locally and at a centralized site by a specialized and general radiologist. RESULTS: Seventy-one patients were diagnosed with colon cancer. Overall, WECT sensitivity and specificity were 98.6 and 95.0%, respectively. Positive and negative predictive values were 92.1 and 99.1%, respectively. In a subgroup of 33 patients with unclean bowel, the sensitivity and specificity of WECT were 95.0 and 92.3%, respectively. The correlation between local radiologists and the specialized radiologist was excellent (Kappa = 0.87) as was the correlation between the general radiologist and the specialist (Kappa = 0.92). CONCLUSION: This prospective analysis demonstrates that WECT is an effective, safe, and simple imaging technique for the diagnosis of colon cancer and can be proposed when a strong clinical suspicion of colon cancer is present, especially in frail patients.

[Posttraumatic pancreatic fistula: successful endoscopic stent placement]. / Fistule pancréatique post-traumatique: succès du traitement endoscopique par endoprothèse.

INTRODUCTION: The risk of complications and the severity of pancreatic trauma depend on the status of the main pancreatic duct. Endoscopic retrograde pancreatography (ERCP) has emerged as the technique of reference for assessing pancreatic ductal anatomy, and it also permits therapeutic intervention by the endoscopic placement of an endoprosthesis. CASE: We report a pancreatic fistula attributable to posttraumatic rupture of the main duct, undiagnosed before ERCP and successfully treated by endoscopic stent placement. DISCUSSION: ERCP has emerged as a tool for both diagnosis and treatment. Major traumatic pancreatic duct disruptions can be diagnosed more easily and managed successfully by endoscopic stent placement, thereby avoiding surgical morbidity. ERCP is impractical in emergency settings for many reasons. Magnetic resonance pancreatography may be useful for establishing the type and extent of pancreatic lesions and for selecting patients for endoscopic treatment.

[Diagnosis of iron overload]. / Diagnostic d'une surcharge en fer.

Hepatic iron overload conditions can be classified as genetic, mainly related to HFE haemochromatosis, and secondary, mainly associated with haematological and hepatic disorders and with metabolic syndrome. The strict affirmation of iron excess relies upon liver biopsy, MRI or calculation of the amount of iron removed through phlebotomies. Determination of its cause relies upon the assessment of transferrin saturation which, when increased, suggests the diagnosis of either haemochromatosis--implying HFE testing--or overload secondary to dysmyelopoiesis or to end-stage cirrhosis, and, when normal, suggests the diagnosis of dysmetabolic iron overload syndrome.