The switch from Gd-DTPA to Gd-DOTA is not associated with decrease of the T1 signal intensity of the pallidus and dentate in a pediatric population.

BACKGROUND: The switch from the linear gadolinium-based contrast agent (GBCA) gadopentate dimeglumine (Gd_DTPA) to the macrocyclic GBCA gadobutrol is associated with a decrease of the T1 signal intensity (SI) in brain gray matter nuclei. The effects of the switch to other macrocyclic GBCAs are not yet established. PURPOSE: To explore the effects of switching from Gd-DTPA to the macrocyclic GBCA gadoterate meglumine (Gd-DOTA) in pediatric patients. MATERIAL AND METHODS: We measured the pallidus/middle cerebellar peduncle (MCP) SI ratio and the dentate/MCP SI ratio in pre-contrast sagittal T1-weighted spin-echo images in nine patients who had received ≥6 administrations of Gd-DTPA and then of Gd-DOTA, in 18 patients who had received ≥6 administrations of Gd-DOTA alone, and in nine age-matched controls without prior GBCA administrations. Serial assessment was performed in patients who switched from Gd-DTPA to Gd-DOTA. Finally, the rate of change of pallidal/MCP and dentate/MCP SI ratios between the first and last Gd-DOTA administrations was compared. RESULTS: The pallidal/MCP and dentate/MCP SI ratios were (P < 0.05) higher in patients with prior Gd-DTPA and Gd-DOTA administrations compared to the controls. After the switch, the pallidal/MCP SI ratio increased in nine patients and the dentate/MCP ratio in seven patients. The rate of change of pallidal/MCP SI ratio after Gd-DOTA was higher (P < 0.01) in patients who had previously received Gd-DTPA (mean 2.89 ± 2.6%) than in patients who had received Gd-DOTA alone (mean 0.53 ± 0.89%). CONCLUSION: T1 SI in gray matter nuclei does not decrease after switching from Gd-DTPA to Gd-DOTA. The switch effects from Gd-DTPA to each macrocyclic GBCA should be individually evaluated.

Quantitative Analysis of Apparent Diffusion Coefficient for Disease Assessment in Paediatric Inflammatory Bowel Disease.

OBJECTIVE: The aim of the study was to establish an apparent diffusion coefficient (ADC) cut-off value to classify active and non-active lesions in inflammatory bowel disease. METHODS: We reviewed 167 paediatric magnetic resonance enterographies executed for suspected inflammatory bowel disease by using a 1.5- and 3-T scanner. We assessed the presence and activity of the disease by using morphologic and functional parameters such as the ADC. Each patient could have more than 1 examinations. Quantitative assessment of disease activity in the ADC map was measured placing 3 regions of interest in the areas of highest inflammation and the mean value was calculated, patients without sign of inflammation were assessed at 2 standardised site. Ileocolonoscopy, esophagogastroduodenoscopy, surgery, and video-capsule endoscopy were used as standards of reference. RESULTS: We enrolled 34 patients and 35 examinations: radiological findings of disease were identified in 29 examinations and 44 lesions were detected. Six patients had negative results and ADC assessment was taken at the terminal ileum and cecum. A total of 56 bowel segments were included in the study. Image analysis revealed 39 active lesions (69.6%) and their ADC values were lower compared to the ones of non-active segments. For each scanner a cut-off value was found (sensitivity: 0.91, specificity: 0.89 for 1.5 T and 0.81 for 3 T). Inter-rater agreement on disease activity between ADC values and magnetic resonance enterography results and between ADC values and the standard of reference were very good. CONCLUSIONS: ADC can provide a scanner-based quantitative measurement of disease activity.

Spontaneous non-aortic retroperitoneal hemorrhage: etiology, imaging characterization and impact of MDCT on management. A multicentric study.

PURPOSE: The purpose of this multicentric study is to assess the usefulness of multiphasic Computed tomography in the identification of spontaneous non-traumatic retroperitoneal hematoma (SRH) and its management, with references to the role of interventional radiology. MATERIALS AND METHODS: From January 2011 to June 2014, 27 patients with SRH were selected. Patients with aortic, traumatic, or iatrogenic source of bleeding were excluded. All the patients were studied with multiphasic MDCT after injection of intravenous contrast. Digital Subtraction angiography and percutaneous embolization treatment were performed. RESULTS: CT identified SRH in all cases (100%), showing the source of bleeding in 11 cases (40%) and pointing out the source of bleeding in 15 cases (55%). In one case (5%), the bleeding origin was recognized only at surgery as adrenal source. CT has identified a contrast medium extravasation in the arterial phase in 17 patients (63%), treated successfully by percutaneous embolization in 13 and by open-surgery in two cases. Two patients died before undergoing intervention and surgery, respectively. Ten patients (37%) were non-operatively treated successfully with clinical, laboratory, and imaging follow-up. CONCLUSIONS: Multiphasic CT is the gold standard for the identification of a SRH. Recognition of CT signs of active bleeding is the crucial feature influencing the timing of therapeutic treatment. Urgent embolization should be performed in cases of arterial bleeding or contained vascular injuries supplying the retroperitoneal hematoma. Surgery is to be addressed in cases of actively bleeding hematomas associated with complication. Finally, an initial more conservative approach can be adopted in patients without signs of contrast extravasation or low-flow active bleeding. Technical skill, expertise, and recognition of CT signs of arterial active bleeding are critical features influencing patients management.

Identification of responders to sorafenib in hepatocellular carcinoma: is tumor volume measurement the way forward?

OBJECTIVES: Early assessment of hepatocellular carcinoma (HCC) response during sorafenib (SO) treatment is challenging, since tumor necrosis, extension and radiological appearance can be inhomogeneous. We evaluated the predictive value of different imaging criteria - such as Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, European Association for the Study of the Liver (EASL), modified RECIST (mRECIST), tumor density and volume variations - in the early follow-up of SO treatment. METHODS: The study included 22 patients. CT images from baseline and 2 months were reviewed to assess response according to RECIST 1.1, mRECIST, EASL, Choi's criteria (decreased tumor density by ≥15%) and arterial-enhancing tumor volume ratio; α-fetoprotein (AFP) variations were expressed as AFP ratio. RESULTS: The response criteria and volume measurements were reproducible (k > 0.80). The overall disease control rate was 40.9% by EASL and mRECIST, and 27.3% by RECIST 1.1; a ≥15% decrease in tumor density was observed in 9 patients (40.9%). The mean volume ratio was 1.73 ± 2.12, the mean AFP ratio 14 ± 37. The 1-year survival rate was 65.9%. Volume ratio was the only predictive factor for survival, with 1-year cumulative survival rates of 90% for volume ratios ≤1.1 and of 45.4% for volume ratios >1.1 (p = 0.04). CONCLUSIONS: Tumor volume measurements are reproducible and might provide an early predictive marker of response in HCC patients treated with SO.