MRI-serum-based score accurately identifies patients undergoing liver transplant without rejection avoiding the need for liver biopsy: A multisite European study.

Serum liver tests (serum tests) and histological assessment for T-cell-mediated rejection are essential for post-liver transplant monitoring. Liver biopsy carries a risk of complications that are preferably avoided in low-risk patients. Multiparametric magnetic resonance imaging (mpMRI) is a reliable noninvasive diagnostic method that quantifies liver disease activity and has prognostic utility. Our aim was to determine whether using mpMRI in combination with serum tests could noninvasively identify low-risk patients who underwent liver transplants who are eligible to avoid invasive liver biopsies. In a multicenter prospective study (RADIcAL2), including 131 adult and pediatric (children and adolescent) patients with previous liver transplants from the Netherlands, Portugal, and the United Kingdom, concomitant mpMRI and liver biopsies were performed. Biopsies were centrally read by 2 expert pathologists. T-cell-mediated rejection was assessed using the BANFF global assessment. Diagnostic accuracy to discriminate no rejection versus indeterminate or T-cell-mediated liver transplant rejection was performed using the area under the receiver operating characteristic curve. In this study, 52% of patients received a routine (protocol) biopsy, while 48% had a biopsy for suspicion of pathology. Thirty-eight percent of patients had no rejection, while 62% had either indeterminate (21%) or T-cell-mediated rejection (41%). However, there was a high interobserver variability (0 < Cohen's Kappa < 0.85) across all histology scores. The combined score of mpMRI and serum tests had area under the receiver operating characteristic curve 0.7 (negative predictive value 0.8) to identify those without either indeterminate or T-cell-mediated rejection. Combining both imaging and serum biomarkers into a composite biomarker (imaging and serum biomarkers) has the potential to monitor the liver graft to effectively risk stratify patients and identify those most likely to benefit from a noninvasive diagnostic approach, reducing the need for liver biopsy.

Diagnostic value of morphological enhancement patterns in the hepatobiliary phase of gadoxetic acid-enhanced MRI to distinguish focal nodular hyperplasia from hepatocellular adenoma.

OBJECTIVES: To describe the different morphological enhancement patterns of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI (Gd-EOB-DTPA MRI) and to determine their added value in their differential diagnosis. METHODS: A retrospective analysis of imaging findings in 185 benign hepatocellular lesions (154 FNH; 31 HCA) in 108 patients who underwent Gd-EOB-DTPA MRI was performed by two independent reviewers. Six patterns on HBP were recorded: 1) homogeneous enhancement; 2) peripheral ring-like enhancement with hypointense central core; 3) peripheral ring-like enhancement with hyperintense central core; 4) central core enhancement with hypointense periphery; 5) heterogeneous enhancement; and 6) the absence of enhancement. RESULTS: Peripheral ring-like enhancement with hypointense central core and peripheral ring-like enhancement with hyperintense central core showed the highest specificity for the diagnosis of FNH (100% and 96.8%, respectively). The absence of enhancement and central core enhancement with hypointense periphery were only present in 0.6% and 1.9% of FHN, respectively. All other patterns were observed with similar frequencies in FNH (22.1% to 26.6%). Six HCA showed contrast uptake on the HBP: homogeneous (6.5%), peripheral ring-like enhancement with hyperintense central core (3.2%) and heterogeneous (9.7%). CONCLUSION: Both FNH and HCA may demonstrate enhancement in the HBP of Gd-EOB-DTPA MRI, limiting its specificity. A significant improvement in specificity can be achieved by the evaluation of morphological enhancement patterns: Peripheral ring-like enhancement with hypointense or hyperintense central core was highly specific for FNH diagnosis. On the other hand, the absence of HBP enhancement makes the diagnosis of FNH unlikely.

Bioenergetic adaptations of the human liver in the ALPPS procedure - how liver regeneration correlates with mitochondrial energy status.

BACKGROUND: The Associating Liver Partition and Portal Ligation for Staged Hepatectomy (ALPPS) depends on a significant inter-stages kinetic growth rate (KGR). Liver regeneration is highly energy-dependent. The metabolic adaptations in ALPPS are unknown. AIMS: i) Assess bioenergetics in both stages of ALPPS (T1 and T2) and compare them with control patients undergoing minor (miHp) and major hepatectomy (MaHp), respectively; ii) Correlate findings in ALPPS with volumetric data; iii) Investigate expression of genes involved in liver regeneration and energy metabolism. METHODS: Five patients undergoing ALPPS, five controls undergoing miHp and five undergoing MaHp. Assessment of remnant liver bioenergetics in T1, T2 and controls. Analysis of gene expression and protein content in ALPPS. RESULTS: Mitochondrial function was worsened in T1 versus miHp; and in T2 versus MaHp (p < 0.05); but improved from T1 to T2 (p < 0.05). Liver bioenergetics in T1 strongly correlated with KGR (p < 0.01). An increased expression of genes associated with liver regeneration (STAT3, ALR) and energy metabolism (PGC-1α, COX, Nampt) was found in T2 (p < 0.05). CONCLUSION: Metabolic capacity in ALPPS is worse than in controls, improves between stages and correlates with volumetric growth. Bioenergetic adaptations in ALPPS could serve as surrogate markers of liver reserve and as target for energetic conditioning.

Morphologic and Molecular Features of Hepatocellular Adenoma with Gadoxetic Acid-enhanced MR Imaging.

PURPOSE: To evaluate the diagnostic performance of imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging to differentiate among hepatocellular adenoma (HCA) subtypes by using the histopathologic results of the new immunophenotype and genotype classification and to correlate the enhancement pattern on the hepatobiliary phase (HBP) with the degrees of expression of organic anion transporting polypeptide (OATP1B1/3), multidrug resistance-associated protein 2 (MRP) (MRP2), and MRP 3 (MRP3) transporters. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, and the requirement for informed consent waived. MR imaging findings of 29 patients with 43 HCAs were assessed by two radiologists independently then compared with the histopathologic analysis as the standard of reference. Receiver operating characteristic curves and Spearman rank correlation coefficient were used to test the diagnostic performance of gadoxetic acid-enhanced MR imaging features, which included the retention or washout at HBP and degree of transporter expression. Interreader agreement was assessed by using the κ statistic with 95% confidence interval. RESULTS: The area under the curve for the diagnosis of inflammatory HCA was 0.79 (95% confidence interval: 0.64, 0.90); for the steatotic type, it was 0.90 (95% confidence interval: 0.77, 0.97); and for the ß-catenin type, it was 0.87 (95% confidence interval: 0.74, 0.95). There were no imaging features that showed a significant statistical correlation for the diagnosis of unclassified HCAs. On immunohistochemical staining, OATP1B1/3 expression was the main determinant for the retention, whereas MRP3 was the key determinant for washout of gadoxetic acid at HBP (P < .001). MRP2 appeared to have no role. CONCLUSION: Gadoxetic acid-enhanced MR imaging features may suggest the subtype of HCA. The degree of OATP1B1/3 and MRP3 expression correlated statistically with gadoxetic acid retention and washout, respectively, in the HBP.

Cardiovascular magnetic resonance imaging assessment of diastolic dysfunction in a population without heart disease: a gender-based study.

OBJECTIVES: Asymptomatic left ventricular (LV) diastolic dysfunction is increasingly recognised as an important diagnosis. Our goal was to study the prevalence and gender differences in subclinical LV diastolic dysfunction, using cardiovascular magnetic resonance imaging (CMR) at 3 T. METHODS: We prospectively studied 48 volunteers (19 male and 29 female, mean age 49 ± 7 years) with no evidence of cardiovascular disease. We used CMR to measure left atrium (LA) and LV volumes, LV peak filling rate and transmitral flow. RESULTS: The overall prevalence of LV diastolic dysfunction in our cohort varied between 20 % (based on evaluation of LV filing profiles) and 24 % (based on the evaluation of the transmitral flow). The prevalence of diastolic dysfunction was higher in men than in women, independently of the criteria used (P between 0.004 and 0.022). Indexed LV end-diastolic volume, indexed LV stroke volume, indexed LV mass, indexed LA minimum volume and indexed LA maximum volume were significantly greater in men than in women (P < 0.05). All the subjects had LV ejection fractions within the normal range. CONCLUSIONS: It is clinically feasible to study diastolic flow and LV filling with CMR. CMR detected diastolic dysfunction in asymptomatic men and women. KEY POINTS: • CMR imaging offers new possibilities in assessing left ventricular diastolic function. • The prevalence of diastolic dysfunction is higher in men than in women. • The prevalence of some diastolic dysfunction in a normal population is 24 %.

Left atrial dysfunction in type 2 diabetes mellitus: insights from cardiac MRI.

OBJECTIVES: The left atrium (LA) modulates left ventricular filling through reservoir, conduit and booster pump functions. Only limited data exist on LA involvement in type 2 diabetes mellitus (DM2). This study sought to assess LA function in asymptomatic DM2 with cardiac MRI. We hypothesized that cardiac MRI can detect LA dysfunction in asymptomatic DM2. METHODS: Forty-five patients with asymptomatic DM2 and 24 normoglycaemic controls were studied. MRI cine imaging was performed to measure LA maximal and minimal volumes. A flow-sensitive phase-contrast gradient-echo sequence was used for flow measurements perpendicular to the orifice of the mitral valve, to quantify active LA stroke volume. LA total, passive and active emptying volumes and fractions were calculated. RESULTS: LA reservoir function, namely LA total ejection fraction, was significantly greater in controls compared to patients with DM2 (62.2 ± 5.2 vs 57.0 ± 7.6 %, P = 0.004). LA passive ejection fraction was also greater in the controls (26.2 ± 9.5 vs 16.1 ± 11.0 %, P < 0.001). Regarding parameters of LA booster pump function, LA active ejection fraction was not significantly different between groups. DM2 was demonstrated to be an independent determinant of LA function. CONCLUSIONS: Cardiac MRI enables the detection of LA dysfunction in asymptomatic DM2, characterized by a reduction in LA reservoir and conduit functions. KEY POINTS: • Evaluation of left atrial function is feasible with cardiac MRI • Type 2 diabetes mellitus is associated with left atrial dysfunction • Left atrial function modulates left ventricular filling.

Left ventricular diastolic function in type 2 diabetes mellitus and the association with coronary artery calcium score: a cardiac MRI study.

OBJECTIVE: The purpose of this study was to compare cardiac MRI-derived parameters of left ventricular (LV) diastolic function between uncomplicated type 2 diabetes mellitus (DM2) and normoglycemic control subjects and to evaluate whether these parameters of LV diastolic function are related to coronary atherosclerosis. SUBJECTS AND METHODS: We prospectively studied 41 subjects with DM2 and 21 normoglycemic control subjects (30 women and 32 men; mean age, 57.2 ± 7.1 [SD] years) with no evidence of overt cardiovascular disease. We used cardiac MRI to measure LV volumes, LV peak filling rate (PFR), and transmitral flow and CT to determine coronary artery calcium scores. RESULTS: Absolute values of the peak filling rate (PFR) were significantly lower in DM2 patients than in control subjects (mean ± SD, 293.2 ± 51.7 vs 375.7 ± 102.8 mL/s, respectively; p < 0.001). Mitral peak E velocities (mean ± SD, 42.8 ± 10.7 vs 48.8 ± 10.4 cm/s; p = 0.040) and peak E velocity-to-peak A velocity ratios (0.88 ± 0.3 vs 1.1 ± 0.3; p = 0.002) were also lower in DM2 patients compared with control subjects. DM2 patients with coronary artery calcification showed a lower PFR normalized to stroke volume (SV) (mean ± SD, 4.4 ± 1.0 vs 5.3 ± 1.4, respectively; p = 0.038) and lower mitral peak E velocities (40.1 ± 11.3 vs 48.0 ± 7.3 cm/s; p = 0.024) than DM2 patients without coronary calcification. PFR normalized to SV was independently associated with the presence of coronary artery calcification (ß = -1.5, p = 0.005). CONCLUSION: DM2 decreases cardiovascular MRI-derived parameters of LV diastolic function. Patients with DM2 and coronary atherosclerosis show a more impaired LV diastolic function than patients without coronary atherosclerosis.

Magnetic resonance imaging for the clinical management of rectal cancer patients: recommendations from the 2012 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting.

OBJECTIVES: To develop guidelines describing a standardised approach regarding the acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for clinical staging and restaging of rectal cancer. METHODS: A consensus meeting of 14 abdominal imaging experts from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) was conducted following the RAND-UCLA Appropriateness Method. Two independent (non-voting) chairs facilitated the meeting. Two hundred and thirty-six items were scored by participants for appropriateness and classified subsequently as appropriate or inappropriate (defined by ≥ 80 % consensus) or uncertain (defined by < 80 % consensus). Items not reaching 80 % consensus were noted. RESULTS: Consensus was reached for 88 % of items: recommendations regarding hardware, patient preparation, imaging sequences, angulation, criteria for MRI assessment and MRI reporting were constructed from these. CONCLUSIONS: These expert consensus recommendations can be used as clinical guidelines for primary staging and restaging of rectal cancer using MRI. KEY POINTS: • These guidelines recommend standardised imaging for staging and restaging of rectal cancer. • The guidelines were constructed through consensus amongst 14 abdominal imaging experts. • Consensus was reached by in 88 % of 236 items discussed.

Diffusion-weighted imaging of the liver: usefulness of ADC values in the differential diagnosis of focal lesions and effect of ROI methods on ADC measurements.

OBJECT: By measuring the apparent diffusion coefficient (ADC) of liver parenchyma and focal hepatic lesions (FHL) we proposed to investigate the utility of ADC in the differential diagnosis of hepatic disease and to determine the influence of region of interest (ROI) characteristics in those measurements. MATERIALS AND METHODS: Ninety-three patients with at least one supracentimetric FHL, or parenchymal abnormality, were retrospectively evaluated. Diagnosis was based on histopathologic data or, alternatively, on a combination of consensus between imaging methods and 24 months of follow-up. Ninety lesions were evaluated with respiratory-triggered diffusion-weighted imaging (b values: 50 and 700 s/mm(2)): 14 hepatocellular carcinomas, 18 metastases, 10 focal nodular hyperplasias, four adenomas, 30 hemangiomas and 14 cysts. ADC of hepatic parenchyma was measured by placing ROIs in four different segments, and in FHLs by using three circular 1 cm(2) ROIs and one ROI encompassing the full lesion. Data was statistically analyzed (p < 0.05 considered significant), and a receiver operating characteristic curve was assessed to evaluate the accuracy for the diagnosis of malignancy. RESULTS: Our measurements showed that parenchyma ADC was significantly higher in segment II and that ADCs of malignant lesions were significantly lower than those of benign lesions (p < 0.001). There was significant overlap between benign solid lesions and malignant lesions and the area under the curve for malignancy was 0.939 (sensitivity 89.7 %, specificity 90.6 %), using a cutoff of 1.43 × 10(-3) mm(2)/s. No significant difference was found between ROIs of different characteristics. CONCLUSION: ADC measurements can help to characterize FHLs and differentiate normal from pathological parenchyma. Any ROI above 1 cm(2) can provide accurate ADC measurements in homogenous lesions.

[Cardiac magnetic resonance stress perfusion: a single-center study]. / Ressonância magnética cardíaca de perfusão em stress: a experiência de um centro nacional.

INTRODUCTION AND OBJECTIVES: Myocardial ischemia can be assessed with cardiac magnetic resonance perfusion imaging (MRPI). This study aimed to analyze the clinical utility of MRPI in the diagnosis of significant coronary artery disease. METHODS: Fifty-five patients were examined with a 1.5 T MR scanner (Siemens Symphony), with a first pass of 0.10 mmol/kg gadolinium chelate, at rest and during adenosine vasodilatation (140µg/kg/min for 4min) using an inversion recovery steady-state free precession sequence. The results were compared with coronary angiography and with SPECT myocardial perfusion images. Agreement for qualitative diagnosis was measured by the kappa coefficient, taking statistical significance as 95%. Minimum clinical follow-up was 12 months. RESULTS: In 19 patients (34.5%) MRPI was negative for myocardial ischemia and necrosis, in 17 (30.9%) it was negative for ischemia but positive for necrosis, in 7 (12.7%) only ischemia was present and in 12 (21.8%) the ischemic area was larger than the necrotic area. The correlation between MRPI and coronary angiography for ischemia detection by coronary artery territory was very good: left anterior descending and right coronary - k=0.8571 (0.59-1), circumflex - k=0.8108 (0.59-1). By contrast, there was no correlation in terms of myocardial ischemia detection between MRPI and SPECT. CONCLUSIONS: MRPI is able to diagnose significant coronary disease in a high risk population, by detection of myocardial ischemia.

One-shot diagnostic and prognostic assessment in intermediate- to high-risk acute pulmonary embolism: the role of multidetector computed tomography.

INTRODUCTION: Contrast-enhanced multidetector computed tomography (MDCT) is useful for the diagnosis of pulmonary embolism (PE). However, current guidelines do not support its use for risk assessment in acute PE patients. OBJECTIVES: We compared the prognostic impact of MDCT-derived indices regarding medium-term mortality in a population of intermediate- to high-risk PE patients, mostly treated by thrombolysis. METHODS: Thirty-nine consecutive patients admitted to an intensive care unit with acute PE were studied. All patients had a pulmonary MDCT on admission to the emergency room as part of the diagnostic algorithm. We assessed the following MDCT variables: right ventricular/left ventricular diameter (RV/LV) ratio, arterial obstruction index, pulmonary artery-to-aorta diameter ratio and azygos vein diameter. A 33-month follow-up was performed. RESULTS: Mean age was 59.1±19.6 years, with 80% of patients receiving thrombolysis. Follow-up all-cause mortality was 12.8%. Of the MDCT-derived variables, only the RV/LV ratio had significant predictive value, being higher in patients who suffered the endpoint (1.6±0.5 vs. 1.9±0.4, p=0.046). Patients with an RV/LV ratio ≥1.8 had 11-fold higher medium-term all-cause mortality (3.8% vs. 38.8%, p<0.001). Regarding this endpoint, the c-statistic was 0.78 (95% CI, 0.60-0.96) for RV/LV ratio and calibration was good (goodness-of-fit p=0.594). No other radiological index was predictive of mortality. CONCLUSIONS: MDCT gives the possibility, in a single imaging procedure, of diagnosing and assessing the prognosis of patients with intermediate- to high-risk PE. Although further studies are needed, the simple-to-calculate RV/LV ratio has good discrimination and calibration for predicting poorer outcomes in patients with acute PE.

Spectral CT: Current Liver Applications.

Using two different energy levels, dual-energy computed tomography (DECT) allows for material differentiation, improves image quality and iodine conspicuity, and allows researchers the opportunity to determine iodine contrast and radiation dose reduction. Several commercialized platforms with different acquisition techniques are constantly being improved. Furthermore, DECT clinical applications and advantages are continually being reported in a wide range of diseases. We aimed to review the current applications of and challenges in using DECT in the treatment of liver diseases. The greater contrast provided by low-energy reconstructed images and the capability of iodine quantification have been mostly valuable for lesion detection and characterization, accurate staging, treatment response assessment, and thrombi characterization. Material decomposition techniques allow for the non-invasive quantification of fat/iron deposition and fibrosis. Reduced image quality with larger body sizes, cross-vendor and scanner variability, and long reconstruction time are among the limitations of DECT. Promising techniques for improving image quality with lower radiation dose include the deep learning imaging reconstruction method and novel spectral photon-counting computed tomography.

Analysis of 665 thyroid nodules using both EU-TIRADS and ACR TI-RADS classification systems.

BACKGROUND: Ultrasound-based classification systems allow stratification of thyroid nodules to recommend fine-needle aspiration (FNA) based on their malignancy risk. However, these have discrepancies that may have an impact in thyroid cancer detection. We aimed to compare European Thyroid Association (EU-TIRADS) and American College of Radiology (ACR TI-RADS), in terms of FNA indication and diagnostic performance. METHODS: Retrospective study of 665 thyroid nodules from 598 patients who underwent ultrasound and fine-needle aspiration at a tertiary-care institution between January 1st of 2016 and July 31st of 2019. Based on their sonographic features they were classified according to the EU-TIRADS and ACR TI-RADS classification and then their cytological results were obtained. Differences in FNA indications according to these two classifications were analysed. In patients who underwent surgical removal of the nodules, the final pathological diagnosis was obtained. RESULTS: A statistically significant association was found between EU-TIRADS and ACR TI-RADS classification systems (p < 0.001). ACR TI-RADS allowed greatest reduction in FNA performed (32% vs 24.5%). A different risk category was obtained in 174 (26.1%) nodules, mostly higher with EU-TIRADS. The indication to FNA changed in 54 (8.1%) nodules (49 only indicated following EU-TIRADS recommendations), of which 4 had Bethesda IV and 5 had Bethesda III cytology. The FNA indication in a higher number of nodules using EU-TIRADS was due to difference in the dimensional threshold for FNA on low-risk nodules; to the fact that hypoechogenicity in a mixed nodule ascribes it moderate risk, while using ACR TI-RADS it would only be considered of low risk, and to the use of isolated sonographic features, namely marked hypoechogenicity, microcalcifications and irregular margins, to automatically categorize a nodules as high risk in EU-TIRADS, while ACR TI-RADS requires a group of potentially suspicious features to consider a nodule of high risk. The analysis of pathology proven nodules revealed equally good sensitivity of both systems in the detection of malignancy, but weak specificity, slightly greater with ACR TI-RADS (27.1% vs 18.6%). CONCLUSIONS: The EU-TIRADS and ACR TI-RADS are both suitable to assess thyroid nodules and through risk stratification avoid unnecessary FNA. FNA was less performed using ACR TI-RADS, which was slightly more efficiency in excluding malignancy.

Diffusion-weighted MRI in rectal cancer: apparent diffusion coefficient as a potential noninvasive marker of tumor aggressiveness.

PURPOSE: To assess the value of diffusion-weighted MR imaging (DWI) as a potential noninvasive marker of tumor aggressiveness in rectal cancer, by analyzing the relationship between tumoral apparent diffusion coefficient (ADC) values and MRI and histological prognostic parameters. MATERIALS AND METHODS: Fifty rectal cancer patients underwent primary staging MRI including DWI before surgery and neo-adjuvant therapy. In 47, surgery was preceded by short-course radiation therapy (n = 28) or long-course chemoradiation therapy (n = 19). Mean tumor ADC was measured and compared between subgroups based on pretreatment CEA levels, MRI parameters (mesorectal fascia - MRF - status; T-stage; N-stage) and histological parameters (differentiation grade: poorly differentiated, poorly moderately differentiated, moderately differentiated, moderately well differentiated, well-differentiated; lymphangiovascular invasion). RESULTS: Mean tumor ADCs differ between MRF-free versus MRF-invaded tumors (P = 0.013), the groups of cN0 versus cN+ cancers (P = 0.011), and between the several groups of histological differentiation grades (P = 0.025). There was no significant difference in mean ADCs between the various groups of CEA levels, the T stage, and the presence of lymphangiovascular invasion. CONCLUSION: Lower ADC values were associated with a more aggressive tumor profile. Significant correlations were found between mean ADC values and radiological MRF status, N stage and differentiation grade. ADC has the potential to become an imaging biomarker of tumor aggressiveness profile.

Congenital cystic lesions of the biliary tree.

OBJECTIVE: The purpose of this essay is to illustrate the imaging findings of congenital cystic lesions of the biliary tract. CONCLUSION: Congenital cystic lesions of the biliary tract include ductal plate malformations and choledochal cysts and can be recognized with characteristic imaging findings and basic knowledge of the embryologic development of the biliary tree.

The accuracy of magnetic resonance imaging in predicting the size of pure ductal carcinoma in situ: a systematic review and meta-analysis.

Ductal carcinoma in situ (DCIS) is a putative precursor of invasive breast cancer and MRI is considered the most sensitive imaging technique for its detection. This study aims to evaluate the accuracy of MRI measuring the pure DCIS size, against pathology, to better understand the role of MRI in the management of this intraductal neoplasm.Potentially eligible studies in MEDLINE, Embase and Google Scholar, up to January 2021 were considered, and a systematic review and meta-analysis according to the published protocol (Prospero-CRD42021232228) was performed. Outcomes of mean differences and accuracy rates were analysed using IBM® SPSS® v26 and random-effect models in platform R v3.3.Twenty-two cross-sectional studies were selected and 15 proceeded to meta-analysis. MRI accurately predicted 55% of the tumours' sizes and, according to Bland-Altman plots, concordance between MRI and pathology was greater for smaller tumours. In the meta-analysis, difference of the means between MRI and pathology was 3.85 mm (CI 95% [-0.92;8.60]) with considerable heterogeneity (I2 = 96.7%). Subgroup analysis showed similar results for sizes between different MRI fields, temporal resolution, slice thickness and acquisition times, but lower heterogeneity in studies using 3-T MRI (I2 = 57.2%). Results were concordant with low risk of bias studies (2.46, CI 95% [0.57-4.36]), without heterogeneity (I2 = 0%).Therefore, MRI is shown to be an accurate method in pure DCIS size assessment. Once the best MRI protocol is established, evaluation of the impact of pure DCIS size in predicting treatment outcomes will contribute to clarifying current issues related to intraductal breast carcinoma.

Rectal cancer: assessment of complete response to preoperative combined radiation therapy with chemotherapy--conventional MR volumetry versus diffusion-weighted MR imaging.

PURPOSE: To determine diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging for assessment of complete tumor response (CR) after combined radiation therapy with chemotherapy (CRT) in patients with locally advanced rectal cancer (LARC) by means of volumetric signal intensity measurements and apparent diffusion coefficient (ADC) measurements and to compare the performance of DW imaging with that of T2-weighted MR volumetry. MATERIALS AND METHODS: A retrospective analysis of 50 patients with LARC, for whom clinical and imaging data were retrieved from a previous imaging study approved by the local institutional ethical committee and for which all patients provided informed consent, was conducted. Patients underwent pre- and post-CRT standard T2-weighted MR and DW MR. Two independent readers placed free-hand regions of interest (ROIs) in each tumor-containing section on both data sets to determine pre- and post-CRT tumor volumes and tumor volume reduction rates (volume). ROIs were copied to an ADC map to calculate tumor ADCs. Histopathologic findings were the standard of reference. Receiver operating characteristic (ROC) curves were generated to compare performance of T2-weighted and DW MR volumetry and ADC. The intraclass correlation coefficient (ICC) was used to evaluate interobserver variability and the correlation between T2-weighted and DW MR volumetry. RESULTS: Areas under the ROC curve (AUCs) for identification of a CR that was based on pre-CRT volume, post-CRT volume, and volume, respectively, were 0.57, 0.70, and 0.84 for T2-weighted MR versus 0.63, 0.93, and 0.92 for DW MR volumetry (P = .15, .02, .42). Pre- and post-CRT ADC and ADC AUCs were 0.55, 0.54, and 0.51, respectively. Interobserver agreement was excellent for all pre-CRT measurements (ICC, 0.91-0.96) versus good (ICC, 0.61-0.79) for post-CRT measurements. ICC between T2-weighted and DW MR volumetry was excellent (0.97) for pre-CRT measurements versus fair (0.25) for post-CRT measurements. CONCLUSION: Post-CRT DW MR volumetry provided high diagnostic performance in assessing CR and was significantly more accurate than T2-weighted MR volumetry. Post-CRT DW MR was equally as accurate as volume measurements of both T2-weighted and DW MR. Pre-CRT volumetry and ADC were not reliable.

Duodenal imaging on the spotlight: from A to Z.

Abdominal computed tomography (CT) is frequently performed to evaluate gastrointestinal pathologic conditions. The majority of the gastrointestinal radiology literature has concentrated on the colon, stomach, and distal small bowel. The duodenum is often overlooked on imaging, namely on CT, but its anatomy (intra and retroperitoneal) and location in such close proximity to other viscera results in involvement by a multitude of primary and secondary processes, some of them exclusive to this bowel segment. While some conditions, like duplications, lipomas, and diverticula, are usually asymptomatic and are incidentalomas that have no pathologic significance, others are symptomatic and very relevant and should be recognized by every general radiologist: development conditions such as annular pancreas and gut malrotation; inflammatory processes such as ulcers and secondary involvement from pancreatitis; neoplastic conditions such as adenocarcinoma, lymphoma, or local extension from adjacent malignancies. They all can be reliably diagnosed with CT. In this article, we demonstrate the typical imaging features of various diseases involving the duodenum, such as developmental, traumatic, inflammatory, infectious, neoplastic, and postsurgical pathologic conditions in alphabetical order, focusing mainly on upper gastrointestinal series (UGIS) and CT but also some radiography, ultrasound, and magnetic resonance (MR) imaging.

The hypointense liver lesion on T2-weighted MR images and what it means.

The vast majority of focal liver lesions are hyperintense on T2-weighted magnetic resonance (MR) images. Rarely, however, hepatic nodules may appear totally or partially hypointense on those images. Causes for this uncommon appearance include deposition of iron, calcium, or copper and are related to the presence of blood degradation products, macromolecules, coagulative necrosis, and other conditions. Although rare, low signal intensity relative to surrounding liver on T2-weighted images may be seen in a wide spectrum of lesions. Examples include cases of focal nodular hyperplasia, hepatocellular adenoma, hepatocellular carcinoma, metastases, leiomyoma, siderotic or dysplastic nodules, nodules in Wilson disease, granuloma, and hydatid cyst. On fat-suppressed T2-weighted images, nodules with a lipomatous component, such as lipoma, angiomyolipoma, hepatocellular adenoma, and hepatocellular carcinoma may also appear partially or totally hypointense. The conjunction of other MR imaging findings and their integration in the clinical setting may allow a correct diagnosis in a considerable proportion of cases. The cause for T2-weighted hypointensity may not be, however, always recognized, and only pathologic correlation may provide the answer. The aims of this work are to discuss the causes and mechanisms of hypointensity of liver lesions on T2-weighted images and proposing an algorithm for classification that may be useful as a quick reminder for the interested reader.

Gastroenterologic and radiologic approach to obscure gastrointestinal bleeding: how, why, and when?

Gastrointestinal (GI) bleeding is a common clinical condition that is increasingly seen in an aging population and frequently requires hospitalization and intervention, with significant morbidity and mortality. Obscure GI bleeding (OGIB) is defined as loss of blood with no source identified after upper endoscopy and colonoscopy. Whether an obscure site of bleeding is clinically evident or silent, it constitutes a diagnostic and therapeutic challenge for the clinician. Gastroenterology and radiology provide the essential diagnostic tools used to evaluate suspected OGIB, each with its strengths and weaknesses. Small bowel series and conventional enteroclysis have a limited role in OGIB. Computed tomographic (CT) enterography and CT enteroclysis are noninvasive techniques with promising results in evaluation of small bowel disease and silent OGIB. CT angiography is a useful triaging tool for diagnosing or excluding active GI hemorrhage, localizing the site of bleeding, and guiding subsequent treatment. Tagged red blood cell scanning is the most sensitive technique for detection of active GI bleeding and allows imaging over a prolonged period, making it useful for detecting intermittent bleeding. Capsule endoscopy has emerged as an important tool for investigating OGIB, but it may soon have competition from double-balloon enteroscopy, a diagnostic technique that can also facilitate therapy.