MRI in Pregnancy and Precision Medicine: A Review from Literature

Magnetic resonance imaging (MRI) offers excellent spatial and contrast resolution for evaluating a wide variety of pathologies, without exposing patients to ionizing radiations. Additionally, MRI offers reproducible diagnostic imaging results that are not operator-dependent, a major advantage over ultrasound. MRI is commonly used in pregnant women to evaluate, most frequently, acute abdominal and pelvic pain or placental abnormalities, as well as neurological or fetal abnormalities, infections, or neoplasms. However, to date, our knowledge about MRI safety during pregnancy, especially about the administration of gadolinium-based contrast agents, which are able to cross the placental barrier, is still limited, raising concerns about possible negative effects on both the mother and the health of the fetus. Contrast agents that are unable to cross the placenta in a way that is safe for the fetus are desirable. In recent years, some preclinical studies, carried out in rodent models, have evaluated the role of long circulating liposomal nanoparticle-based blood-pool gadolinium contrast agents that do not penetrate the placental barrier due to their size and therefore do not expose the fetus to the contrast agent during pregnancy, preserving it from any hypothetical risks. Hence, we performed a literature review focusing on contrast and non-contrast MRI use during pregnancy.

Diagnostic value of DWI-MRI for the detection of acute plaques in the relapse phase of multiple sclerosis

Background. The 2010 revision of the McDonald criteria, widely used for the diagnosis of multiple sclerosis (MS), has established that dissemination in time (DIT) can be demonstrated by the simultaneous presence of asymptomatic gadolinium-enhancing and non-enhancing plaques on a single magnetic resonance imaging (MRI). When the use of gadolinium contrast agents is contraindicated, diffusion-weighted imaging (DWI) is utilized to confirm diffusion alterations in active inflammatory plaques. This study intended to examine whether DWI can be a viable alternative to contrast-enhanced T1-weighted imaging for demonstrating DIT in MS. Material and methods.We assessed 30 previously diagnosed MS patients during acute relapse (based on the 2010 McDonald criteria) and evaluated their brain MRI via DWI‚ contrast-enhanced T1-weighted imaging, and FLAIR sequences. Asymptomatic plaques were defined as either hyperintense or non-hyperintense in DWI and enhancing or non-enhancing in T1GAD-MRI. Statistical indices for the prediction of plaque enhancement in T1 GAD-MRI via DWI-MRI were calculated and compared. Results. The 30 participants in our study had a total of 925 demyelinating plaques that were larger than 3mm in size and presented to be hyperintense in FLAIR-MRI. Diffusion hyperintensity and plaque enhancement were significantly correlated. The sensitivity‚ specificity, positive predictive value‚ negative predictive value, and accuracy of DWI were calculated to be 69.66%‚ 99.76%‚ 96.88%‚ 96.86%, and 96.86%, respectively. Conclusions. Hyperintense DWI findings do not necessarily overlap with contrast enhancements in T1 GAD-MRI. DWI was shown to produce a higher rate of false-positive results. Our study concludes that although T1 GAD-MRI should not be replaced by DWI to determine DIT due to its lower specificity, DWI’s continued use as a surrogate screening imaging sequence whenever the use of T1GAD-MRI is of concern is not without its merits.

An albumin-binding Gd-HPDO3A contrast agent for improved intravascular retention

Gadolinium contrast agents that bind to human serum albumin (HSA) can achieve significantly higher relaxivity values and show improved vascular retention time. Most contrast agents of this design are linear...

MRI for the diagnosis and staging of deeply infiltrating endometriosis: a national survey of BSGE accredited endometriosis centres and review of the literature

Objectives: Our objective was to establish the primary mode of imaging and MR protocols utilised in the preoperative staging of deeply infiltrating endometriosis in centres accredited by the British Society of Gynaecological Endoscopy (BSGE). Methods: The lead consultant radiologist in each centre was invited to complete an online survey detailing their protocols. Results Out of 49 centres, 32 (65%) responded to the survey. Two centres performed transvaginal ultrasound as the primary method for preoperative staging of deeply infiltrating endometriosis and the remainder performed MRI. 21/25 centres did not recommend a period of fasting prior to MRI and 22/25 administered hyoscine butylbromide. None of the centres routinely offered bowel preparation or recommended a specific pre-procedure diet. 21/25 centres did not time imaging according to the woman’s menstrual cycle, and instructions regarding bladder filling were varied. Rectal and vaginal opacification methods were infrequently utilised. All centres preferentially performed MRI in the supine position – six used an abdominal strap and four could facilitate prone imaging. Just under half of centres used pelvic-phased array coils and three centres used gadolinium contrast agents routinely. All centres performed T1W with fat-suppression and T2W without fat-suppression sequences. There was significant variation relating to other MR sequences depending on the unit. Conclusions: There was significant inconsistency between centres in terms of MR protocols, patient preparation and the sequences performed. Many practices were out of line with current published evidence. Advances in knowledge: Our survey demonstrates a need for evidence-based standardisation of imaging in BSGE accredited endometriosis centres.

New generation of oxide-based nanoparticles for the applications in early cancer detection and diagnostics

Hereby the possible applications of oxide nanoparticles in the cancer diagnostics and therapy are presented. Cancer diseases are nowadays one of the most common causes of death in the highly-developed countries. Discussed will be the current clinical cancer detection methods with their shortcomings. The role of nanomedicine in cancer medicine and the potential applications of nanoparticles debated in the literature will be critically evaluated. In the second part, the most common methods for the nanoparticle synthesis will be discussed. Finally, the system for cancer detection based on the enhanced permeation-retention of multimodal high-k oxide nanoparticles doped with lanthanides will be proposed for both for themagnetic resonance imaging (non-gadolinium contrast agents) and for fluorescence guided biopsy and surgery.