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Recent years have seen a resurgence of interest in inexpensive low magnetic field (< 0.3 T) MRI systems mainly due to advances in magnet, coil and gradient set designs. Most of these advances have focused on improving hardware and signal acquisition strategies, and far less on the use of advanced image reconstruction methods to improve attainable image quality at low field. We describe here the use of our end-to-end deep neural network approach (AUTOMAP) to improve the image quality of highly noise-corrupted low-field MRI data. We compare the performance of this approach to two additional state-of-the-art denoising pipelines. We find that AUTOMAP improves image reconstruction of data acquired on two very different low-field MRI systems: human brain data acquired at 6.5 mT, and plant root data acquired at 47 mT, demonstrating SNR gains above Fourier reconstruction by factors of 1.5- to 4.5-fold, and 3-fold, respectively. In these applications, AUTOMAP outperformed two different contemporary image-based denoising algorithms, and suppressed noise-like spike artifacts in the reconstructed images. The impact of domain-specific training corpora on the reconstruction performance is discussed. The AUTOMAP approach to image reconstruction will enable significant image quality improvements at low-field, especially in highly noise-corrupted environments.

Spatially fractionated radiotherapy (SFRT) is characterized by the coexistence of multiple hot and cold dose subregions throughout the treatment volume. In preclinical studies using single-fraction treatment, SFRT can achieve a significantly higher therapeutic index than conventional radiotherapy (RT). Published clinical studies of SFRT followed by RT have reported promising results for bulky tumors. Several clinical trials are currently underway to further explore the clinical benefits of SFRT. However, we lack the important understanding of the correlation between dosimetric parameters and treatment response that we have in RT. In this work, we reviewed and analyzed this important correlation from previous preclinical SFRT studies. We reviewed studies prior to 2022 that treated animal-bearing tumors with minibeam radiotherapy (MBRT) or microbeam radiotherapy (MRT). Eighteen studies met our selection criteria. Increased lifespan (ILS) relative to control was used as the treatment response. The preclinical SFRT dosimetric parameters analyzed were peak dose, valley dose, average dose, beam width, and beam spacing. We found that valley dose was the dosimetric parameter with the strongest correlation with ILS (p-value < 0.01). For studies using MRT, average dose and peak dose were also significantly correlated with ILS (p-value < 0.05). This first comprehensive review of preclinical SFRT studies shows that the valley dose (rather than the peak dose) correlates best with treatment outcome (ILS).

The differential diagnosis of parkinsonian syndromes is considered one of the most challenging in neurology and error rates in the clinical diagnosis can be high even at specialized centres. Despite several limitations, magnetic resonance imaging (MRI) has undoubtedly enhanced the diagnostic accuracy in the differential diagnosis of neurodegenerative parkinsonism over the last three decades. This review aims to summarize research findings regarding the value of the different MRI techniques, including advanced sequences at high- and ultra-high-field MRI and modern image analysis algorithms, in the diagnostic work-up of Parkinson’s disease. This includes not only the exclusion of alternative diagnoses for Parkinson’s disease such as symptomatic parkinsonism and atypical parkinsonism, but also the diagnosis of early, new onset, and even prodromal Parkinson’s disease.

Purpose 68 Ga-labelled HBED-CC-PSMA is a highly promising tracer for imaging recurrent prostate cancer (PCa). The intention of this study was to evaluate the feasibility of PET/MRI with this tracer. Methods Twenty patients underwent PET/CT 1 h after injection of the 68 Ga-PSMA ligand followed by PET/MRI 3 h after injection. Data from the two investigations were first analysed separately and then compared with respect to tumour detection rate and radiotracer uptake in various tissues. To evaluate the quantification accuracy of the PET/MRI system, differences in SUVs between PET/CT and corresponding PET/MRI were compared with differences in SUVs between PET/CT 1 h and 3 h after injection in another patient cohort. This cohort was investigated using the same PET/CT system. Results With PET/MRI, different diagnostic sequences, higher contrast of lesions and higher resolution of MRI enabled a subjectively easier evaluation of the images. In addition, four unclear findings on PET/CT could be clarified as characteristic of PCa metastases by PET/MRI. However, in PET images of the PET/MRI, a reduced signal was observed at the level of the kidneys (in 11 patients) and around the urinary bladder (in 15 patients). This led to reduced SUVs in six lesions. SUV mean values provided by the PET/MRI system were different in muscles, blood pool, liver and spleen. Conclusion PCa was detected more easily and more accurately with Ga-PSMA PET/MRI than with PET/CT and with lower radiation exposure. Consequently, this new technique could clarify unclear findings on PET/CT. However, scatter correction was challenging when the specific 68 Ga-PSMA ligand was used. Moreover, direct comparison of SUVs from PET/CT and PET/MR needs to be conducted carefully.

Brain diseases including neurological disorders and tumors remain under treated due to the challenge to access the brain, and blood-brain barrier (BBB) restricting drug delivery which, also profoundly limits the development of pharmacological treatment. Focused ultrasound (FUS) with microbubbles is the sole method to open the BBB noninvasively, locally, and transiently and facilitate drug delivery, while translation to the clinic is challenging due to long procedure, targeting limitations, or invasiveness of current systems. In order to provide rapid, flexible yet precise applications, we have designed a noninvasive FUS and monitoring system with the protocol tested in monkeys (from in silico preplanning and simulation, real-time targeting and acoustic mapping, to post-treatment assessment). With a short procedure (30 min) similar to current clinical imaging duration or radiation therapy, the achieved targeting (both cerebral cortex and subcortical structures) and monitoring accuracy was close to the predicted 2-mm lower limit. This system would enable rapid clinical transcranial FUS applications outside of the MRI system without a stereotactic frame, thereby benefiting patients especially in the elderly population.

Skeletal muscle is the most abundant tissue in the body and serves various physiological functions including the generation of movement and support. Whole body motor function requires adequate quantity, geometry, and distribution of muscle. This raises the question: how do muscles scale with subject size in order to achieve similar function across humans? While much of the current knowledge of human muscle architecture is based on cadaver dissection, modern medical imaging avoids limitations of old age, poor health, and limited subject pool, allowing for muscle architecture data to be obtained in vivo from healthy subjects ranging in size. The purpose of this study was to use novel fast-acquisition MRI to quantify volumes and lengths of 35 major lower limb muscles in 24 young, healthy subjects and to determine if muscle size correlates with bone geometry and subject parameters of mass and height. It was found that total lower limb muscle volume scales with mass (R2=0.85) and with the height–mass product (R2=0.92). Furthermore, individual muscle volumes scale with total muscle volume (median R2=0.66), with the height–mass product (median R2=0.61), and with mass (median R2=0.52). Muscle volume scales with bone volume (R2=0.75), and muscle length relative to bone length is conserved (median s.d.=2.1% of limb length). These relationships allow for an arbitrary subject's individual muscle volumes to be estimated from mass or mass and height while muscle lengths may be estimated from limb length. The dataset presented here can further be used as a normative standard to compare populations with musculoskeletal pathologies.

Cerebello-thalamo-cortical network is suggested to be involved in the pathophysiology of Essential Tremor (ET). 23 patients with ET and 23 matched HC underwent a 3T-MRI with acquisition of a resting state sequence. Connectivity was investigated using a seed-based regression analyses approach. In ET patients were observed: Reduced connectivity between left primary motor cortex (M1) seed and right premotor cortex and cerebellum and bilateral premotor, parietal areas, supplementary motor area (SMA); I ncreased connectivity between left somatosensory cortex (S1) seed and parietal areas, M1, premotor cortex, SMA; reduced connectivity of this seed with cerebellum. Increased connectivity of SMA seed with premotor cortex and decreased with parietal and precentral areas; Increased connectivity between left thalamus seed and cerebellum; Reduced connectivity between right cerebellum seeds and other cerebellar areas, precentral and premotor areas . ET showed altered connectivity within the cortical sensory-motor network and between cerebral cortex and cerebellum. The increased connectivity between cerebellum and thalamus is consistent with their crucial role in tremor generation. These findings support the dynamical entrainment of multiple central oscillators throughout the cerebello-thalamo-cortical network in ET. This evidence is strengthened by the finding that this network is altered also when the core symptom is absent.

Salmonella spp., Escherichia coli, and Staphylococcus aureus are common microbial contaminants within the homology of medicine and food that can cause serious food poisoning. This study describes a highly efficient, sensitive, specific, and simple multiplex real‐time quantitative PCR (mRT‐qPCR) method for the simultaneous detection of viable Salmonella spp., E. coli, and S. aureus. Primers and probes were designed for the amplification of the target genes invA, uidA, and nuc. Dead bacterial genetic material was excluded by propidium monoazide (PMA) treatment, facilitating the detection of only viable bacteria. This method was capable of detecting Salmonella spp., E. coli, and S. aureus at 102, 102, and 101 CFU/ml, respectively, in pure culture. PMA combined with mRT‐qPCR can reliably distinguish between dead and viable bacteria with recovery rates from 95.7% to 105.6%. This PMA‐mRT‐qPCR technique is a highly sensitive and specific method for the simultaneous detection of three pathogens within the homology of medicine and food. This study established an efficient, sensitive, specific, and simple multiplex real‐time quantitative PCR (mRT‐qPCR) method for the simultaneous detection of viable Salmonella spp., Escherichia coli, and Staphylococcus aureus in bird's nest, donkey‐hide gelatin, and wolfberry. This method was capable of detecting Salmonella spp., E. coli, and S. aureus at 102, 102, and 101 CFU/ml, respectively, in pure culture. And, the PMA combined with mRT‐qPCR can reliably distinguish between dead and viable bacteria with recovery rates from 95.7% to 105.6%. This study describes a highly efficient, sensitive, specific, and simple multiplex real‐time quantitative PCR (mRT‐qPCR) method for the simultaneous detection of viable Salmonella spp., E. coli, and S. aureus.

Objectives To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. Methods After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Results Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Conclusion Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. Key points • Contrast-enhanced spectral mammography (CESM) is slowly being introduced into clinical practice. • Access to breast MRI is limited by availability and lack of reimbursement. • Initial results show a better sensitivity of CESM and MRI than conventional mammography. • CESM showed a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography offers promise, seemingly providing information comparable to MRI.

Molecular radiotherapy (MRT) has demonstrated unique therapeutic advantages in the treatment of an increasing number of cancers. As with other treatment modalities, there is related toxicity to a number of organs at risk. Despite the large number of clinical trials over the past several decades, considerable uncertainties still remain regarding the optimization of this therapeutic approach and one of the vital issues to be answered is whether an absorbed radiation dose–response exists that could be used to guide personalized treatment. There are only limited and sporadic data investigating MRT dosimetry. The determination of dose–effect relationships for MRT has yet to be the explicit aim of a clinical trial. The aim of this article was to collate and discuss the available evidence for an absorbed radiation dose–effect relationships in MRT through a review of published data. Based on a PubMed search, 92 papers were found. Out of 79 studies investigating dosimetry, an absorbed dose–effect correlation was found in 48. The application of radiobiological modelling to clinical data is of increasing importance and the limited published data on absorbed dose–effect relationships based on these models are also reviewed. Based on National Cancer Institute guideline definition, the studies had a moderate or low rate of clinical relevance due to the limited number of studies investigating overall survival and absorbed dose. Nevertheless, the evidence strongly implies a correlation between the absorbed doses delivered and the response and toxicity, indicating that dosimetry-based personalized treatments would improve outcome and increase survival.