MRI in addition to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): an international, multicentre, prospective, diagnostic accuracy trial.

BACKGROUND: Guidelines are inconclusive on whether contrast-enhanced MRI using gadoxetic acid and diffusion-weighted imaging should be added routinely to CT in the investigation of patients with colorectal liver metastases who are scheduled for curative liver resection or thermal ablation, or both. Although contrast-enhanced MRI is reportedly superior than contrast-enhanced CT in the detection and characterisation of colorectal liver metastases, its effect on clinical patient management is unknown. We aimed to assess the clinical effect of an additional liver contrast-enhanced MRI on local treatment plan in patients with colorectal liver metastases amenable to local treatment, based on contrast-enhanced CT. METHODS: We did an international, multicentre, prospective, incremental diagnostic accuracy trial in 14 liver surgery centres in the Netherlands, Belgium, Norway, and Italy. Participants were aged 18 years or older with histological proof of colorectal cancer, a WHO performance status score of 0-4, and primary or recurrent colorectal liver metastases, who were scheduled for local therapy based on contrast-enhanced CT. All patients had contrast-enhanced CT and liver contrast-enhanced MRI including diffusion-weighted imaging and gadoxetic acid as a contrast agent before undergoing local therapy. The primary outcome was change in the local clinical treatment plan (decided by the individual clinics) on the basis of liver contrast-enhanced MRI findings, analysed in the intention-to-image population. The minimal clinically important difference in the proportion of patients who would have change in their local treatment plan due to an additional liver contrast-enhanced MRI was 10%. This study is closed and registered in the Netherlands Trial Register, NL8039. FINDINGS: Between Dec 17, 2019, and July 31, 2021, 325 patients with colorectal liver metastases were assessed for eligibility. 298 patients were enrolled and included in the intention-to-treat population, including 177 males (59%) and 121 females (41%) with planned local therapy based on contrast-enhanced CT. A change in the local treatment plan based on liver contrast-enhanced MRI findings was observed in 92 (31%; 95% CI 26-36) of 298 patients. Changes were made for 40 patients (13%) requiring more extensive local therapy, 11 patients (4%) requiring less extensive local therapy, and 34 patients (11%) in whom the indication for curative-intent local therapy was revoked, including 26 patients (9%) with too extensive disease and eight patients (3%) with benign lesions on liver contrast-enhanced MRI (confirmed by a median follow-up of 21·0 months [IQR 17·5-24·0]). INTERPRETATION: Liver contrast-enhanced MRI should be considered in all patients scheduled for local treatment for colorectal liver metastases on the basis of contrast-enhanced CT imaging. FUNDING: The Dutch Cancer Society and Bayer AG - Pharmaceuticals.

Lesions hyper- to isointense to surrounding liver in the hepatobiliary phase of gadoxetic acid-enhanced MRI.

OBJECTIVES: Hyper- or isointensity in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI has high specificity for focal nodular hyperplasia (FNH) but may be present in hepatocellular adenoma and carcinoma (HCA/HCC). This study aimed to identify imaging characteristics differentiating FNH and HCA/HCC. MATERIALS AND METHODS: This multicenter retrospective cohort study included patients with pathology-proven FNH or HCA/HCC, hyper-/isointense in the HBP of gadoxetic acid-enhanced MRI between 2010 and 2020. Diagnostic performance of imaging characteristics for the differentiation between FNH and HCA/HCC were reported. Univariable analyses, multivariable logistic regression analyses, and classification and regression tree (CART) analyses were conducted. Sensitivity analyses evaluated imaging characteristics of B-catenin-activated HCA. RESULTS: In total, 124 patients (mean age 40 years, standard deviation 10 years, 108 female) with 128 hyper-/isointense lesions were included. Pathology diagnoses were FNH and HCA/HCC in 64 lesions (50%) and HCA/HCC in 64 lesions (50%). Imaging characteristics observed exclusively in HCA/HCC were raster and atoll fingerprint patterns in the HBP, sinusoidal dilatation on T2-w, hemosiderin, T1-w in-phase hyperintensity, venous washout, and nodule-in-nodule partification in the HBP and T2-w. Multivariable logistic regression and CART additionally found a T2-w scar indicating FNH, less than 50% fat, and a spherical contour indicating HCA/HCC. In our selected cohort, 14/48 (29%) of HCA were B-catenin activated, most (13/14) showed extensive hyper-/isointensity, and some had a T2-w scar (4/14, 29%). CONCLUSION: If the aforementioned characteristics typical for HCA/HCC are encountered in lesions extensively hyper- to isointense, further investigation may be warranted to exclude B-catenin-activated HCA. CLINICAL RELEVANCE: Hyper- or isointensity in the HBP of gadoxetic acid-enhanced MRI is specific for FNH, but HCA/HCC can also exhibit this feature. Therefore, we described imaging patterns to differentiate these entities. KEY POINTS: FNH and HCA/HCC have similar HBP intensities but have different malignant potentials. Six imaging patterns exclusive to HCA/HCC were identified in this lesion population. These features in liver lesions hyper- to isointense in the HBP warrant further evaluation.

Evaluation of National Surgical Practice for Lateral Lymph Nodes in Rectal Cancer in an Untrained Setting.

BACKGROUND: Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level. METHODS: Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either 'node-picking' (the removal of an individual LLN) or 'partial regional node dissection' (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (≥7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those  undergoing only rectal resection. RESULTS: Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7-3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2-2.5, p = 0.874). CONCLUSION: Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research.

Response to Letter: Intrapatient Comparison of the Hepatobiliary Phase of Gd-BOPTA and Gd-EOB-DTPA in the Differentiation of HCA From FNH.

LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3 J. Magn. Reson. Imaging 2020;52:1281-1282.

Intrapatient Comparison of the Hepatobiliary Phase of Gd-BOPTA and Gd-EOB-DTPA in the Differentiation of Hepatocellular Adenoma From Focal Nodular Hyperplasia.

BACKGROUND: Current imaging guidelines do not specify the preferred hepatobiliary contrast agent when differentiating hepatocellular adenoma (HCA) from focal nodular hyperplasia (FNH) on MRI. PURPOSE: To analyze intrapatient differences in the hepatobiliary phase (HBP) after use of both gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB-DTPA)-enhanced MRI to differentiate HCA from FNH. STUDY TYPE: Retrospective. POPULATION: Patients who underwent both Gd-BOPTA and Gd-EOB-DTPA-enhanced MRI, including 33 patients with 82 lesions (67 HCA; 15 FNH), with a step-down reference standard of pathology, 20% regression, identical appearance to earlier biopsied lesions, and stringent imaging findings. FIELD STRENGTH/SEQUENCE: 1.5T and 3T HBP of Gd-BOPTA and Gd-EOB-DTPA-enhanced MRI, precontrast fat-suppressed T1 -weighted sequence. ASSESSMENT: Signal intensities relative to the surrounding liver in the HBP were assessed by two observers. STATISTICAL TESTS: Sensitivity and specificity of HCA diagnosis were calculated for both contrast agents. Interobserver agreement was evaluated using Cohen's kappa; differences in degree of certainty for scoring a lesion were calculated by means of the Wilcoxon signed rank test. Differences in signal intensity between Gd-BOPTA and Gd-EOB-DTPA were calculated using McNemar's test. RESULTS: Almost perfect agreement was found between observers for scored signal intensities with both contrast agents. In 30 of the 82 lesions (37%) a difference was observed between contrast agents in the HBP, with Gd-EOB-DTPA proving correct in all but one of the discordant lesions. When distinguishing HCA from FNH, Gd-BOPTA showed a sensitivity of 46% (31/67) and a specificity of 87% (13/15), while the sensitivity and specificity of Gd-EOB-DTPA was 85% (57/67) and 100% (15/15), respectively. A risk of misclassifying HCA as FNH typically occurs for Gd-BOPTA when lesions are intrinsically hyperintense (P < 0.005). DATA CONCLUSION: The HBP of Gd-EOB-DTPA shows superior accuracy in ruling out HCA in comparison with Gd-BOPTA, especially when the lesion is intrinsically hyperintense on T1 -weighted imaging. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:700-710.

Bowel preparation in MRI for detection of endometriosis: Comparison of the effect of an enema, no additional medication and intravenous butylscopolamine on image quality.

PURPOSE: To compare the effect of three different patient preparation strategies for reducing bowel motion on image quality in pelvic MRI. METHODS: Retrospective study in which 95 consecutive patients undergoing pelvic MRI were subdivided based on preparation type for reduction of bowel motion: group 1 (N = 31) fasted 4 h and applied an enema (Bisacodyl 10 mg); group 2 (N = 32) received no medication; group 3 (N = 32) received intravenous butylscopolamine (Buscopan® 50 mg). Image quality was reviewed by visual assessment of delineation (3-point-scale) of pelvic structures: uterus, adnexa, bladder, rectum, sigmoid, uterosacral ligaments, round ligaments and small bowel. As secondary endpoint the presence of rectal wall edema was evaluated. Interobserver agreement was calculated, as well as relative diagnostic odds ratios (RDOR) for the protocols to provide an outcome in the best delineation category. RESULTS: Interobserver agreement proportions varied from 0.48 to 1.00. The rectum and sigmoid colon respectively have a 5.4 and 2.6 RDOR when butylscopolamine is applied compared to Bisacodyl (P = 0.051; P = 0.008), and a 4.2 and 5.7 times higher RDOR with Bisacodyl preparation compared to no medical preparation (P = 0.006; P < 0.01). Small bowel delineation was significantly better with butylscopolamine compared to Bisacodyl (P = 0.007). There was no significant difference in delineation of the other structures between protocols. There is a significant higher chance of observing rectal wall edema with Bisacodyl compared to the other protocols (both P < 0.001). CONCLUSIONS: Butylscopolamine provides better delineation of the small bowel and rectosigmoid compared to Bisacodyl, which in turn, provides better delineation of the rectosigmoid compared to no medication. Moreover, Bisacodyl causes rectal wall edema in the majority of cases.

[An infant with a bowed lower leg]. / Een zuigeling met een gebogen onderbeen.

The parents of a 5-month-old boy noticed bowing of his left leg. Radiographic survey showed an anterolateral bowing of the left tibia and fibula with intramedullary sclerosis, typical for neurofibromatosis type 1. As the mother had neurofibromatosis, this boy was diagnosed with neurofibromatosis type 1.