Unveiling the Temporal Aspect of MRI Tattoo Reactions: A Prospective Evaluation of a Newly-Acquired Tattoo with Multiple MRI Scans.

BACKGROUND Over the past 30 years, painful reactions during magnetic resonance imaging (MRI) in tattooed individuals have been sporadically reported. These complications manifest as burning pain in tattooed skin areas, occasionally with swelling and redness, often leading to termination of the scanning. The exact cause is unclear, but iron oxide pigments in permanent make-up or elements in carbon black tattoos may play a role. Additionally, factors like tattoo age, design, and color may influence reactions. The existing literature lacks comprehensive evidence, leaving many questions unanswered. CASE REPORT We present the unique case of a young man who experienced recurring painful reactions in a recently applied black tattoo during multiple MRI scans. Despite the absence of ferrimagnetic ingredients in the tattoo ink, the patient reported intense burning sensations along with transient erythema and edema. Interestingly, the severity of these reactions gradually decreased over time, suggesting a time-dependent factor contributing to the problem. This finding highlights the potential influence of pigment particle density in the skin on the severity and risk of MRI interactions. We hypothesize that the painful sensations could be triggered by excitation of dermal C-fibers by conductive elements in the tattoo ink, likely carbon particles. CONCLUSIONS Our case study highlights that MRI-induced tattoo reactions may gradually decrease over time. While MRI scans occasionally can cause transient reactions in tattoos, they do not result in permanent skin damage and remain a safe and essential diagnostic tool. Further research is needed to understand the mechanisms behind these reactions and explore preventive measures.

Magnetite Alters the Metabolic Interaction between Methanogens and Sulfate-Reducing Bacteria.

It is known that the presence of sulfate decreases the methane yield in the anaerobic digestion systems. Sulfate-reducing bacteria can convert sulfate to hydrogen sulfide competing with methanogens for substrates such as H2 and acetate. The present work aims to elucidate the microbial interactions in biogas production and assess the effectiveness of electron-conductive materials in restoring methane production after exposure to high sulfate concentrations. The addition of magnetite led to a higher methane content in the biogas and a sharp decrease in the level of hydrogen sulfide, indicating its beneficial effects. Furthermore, the rate of volatile fatty acid consumption increased, especially for butyrate, propionate, and acetate. Genome-centric metagenomics was performed to explore the main microbial interactions. The interaction between methanogens and sulfate-reducing bacteria was found to be both competitive and cooperative, depending on the methanogenic class. Microbial species assigned to the Methanosarcina genus increased in relative abundance after magnetite addition together with the butyrate oxidizing syntrophic partners, in particular belonging to the Syntrophomonas genus. Additionally, Ruminococcus sp. DTU98 and other species assigned to the Chloroflexi phylum were positively correlated to the presence of sulfate-reducing bacteria, suggesting DIET-based interactions. In conclusion, this study provides new insights into the application of magnetite to enhance the anaerobic digestion performance by removing hydrogen sulfide, fostering DIET-based syntrophic microbial interactions, and unraveling the intricate interplay of competitive and cooperative interactions between methanogens and sulfate-reducing bacteria, influenced by the specific methanogenic group.