A method for rapid morphologic phenotyping is demonstrated by using magnetic resonance microscopy. Whole fixed C57BL/6J mice were imaged at 110-μm isotropic resolution; limited volumes of the intact specimen, at 50-μm isotropic resolution; and isolated organs, at 25-μm isotropic resolution. The three-dimensional imaging technique was applied to uricase knockout mice to demonstrate the method for the evaluation of morphologic phenotype. Supplemental material: (radiology.rsnajnls.org/cgi/content/full/2223010531/DC1) © RSNA, 2002

Morphologic phenotyping with MR microscopy: the visible mouse.

http://www.paul-tofts-phd.org.uk/CV/reprints/B143_2DqMT_2002.pdf

Precise estimate of fundamental in-vivo MT parameters in human brain in clinically feasible times

The purpose of this study was to determine if MnSO4/doxorubicin (DOX) loaded liposomes could be used for in vivo monitoring of liposome concentration distribution and drug release using MRI. In vitro results show that T1 shortening correlates with MnSO4 concentration. Using a temperature-sensitive liposome formulation, it was found that MnSO4 release significantly shortened T1. This feature, therefore, suggests that content release can also be measured with these MnSO4-loaded liposomes. The feasibility of monitoring this drug delivery and release-imaging agent was shown in a murine tumor model. Upon tumor heating, nonthermally sensitive liposomes selectively but heterogeneously accumulated in the tumor region. The thermally sensitive liposomes showed a clear pattern of accumulation at the periphery of the tumor, concordant with the release temperature of this formulation (39 – 40°C). This liposome contrast agent has potential for use with hyperthermia by providing individualized monitoring of tissue drug concentration distribution during or after treatment. This would allow for: 1) modification of treatment variables to improve the uniformity of drug delivery, and 2) provide a means to select patients most likely to benefit from this liposomal drug treatment. Additionally, the drug-loading method used for this liposome is applicable to a wide range of drugs, thereby broadening its applicability. The method is also applicable to other liposomal formulations with triggered release mechanisms. Magn Reson Med 51: 1153–1162, 2004. © 2004 Wiley-Liss, Inc.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/mrm.20074

In vivo monitoring of tissue pharmacokinetics of liposome/drug using MRI: Illustration of targeted delivery

Purpose: To investigate the use of a three-pool relaxation model to measure myelin, myelinated-axon, and mixed water-pool fractions in white matter (WM) during myelination Materials and Methods: MRI at 19 Tesla, and conventional spin-echo imaging were used to acquire T1 and T2 relaxation data in 15 normal children ranging in age from 3 months to 13 years 4 months Three equations with three unknowns were solved to calculate three water-pool fractions for each child in a frontal association-fiber area and a frontal-parietal projection-fiber area The temporal trend of the fractions was compared with a theoretical three-pool myelination model Results: The myelin level in the projection-fiber area rose earlier than in the association-fiber area following the standard caudal-to-rostral trend The temporal trend of the three-pool fractions followed that predicted by the theoretical myelination model in both brain areas The myelinatedaxon and mixed pool sizes were significantly different in the two WM areas following early myelination, although their myelin pools were similar T1 values correlated more highly with the myelinated-axon and mixed pool fractions than with the myelin pool fraction

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmri.10230

Three-pool model of white matter.

Effective cancer chemotherapy depends on the delivery of therapeutic drugs to cancer cells at cytotoxic concentrations. However, physiologic barriers, such as variable vessel permeability, high interstitial fluid pressure, and heterogeneous perfusion, make it difficult to achieve that goal. Efforts to improve drug delivery have been limited by the lack of noninvasive tools to evaluate intratumoral drug concentration and distribution. Here we demonstrate that tumor drug concentration can be measured in vivo using T1‐weighted MRI, following systemic administration of liposomes containing both drug (doxorubicin (DOX)) and contrast agent (manganese (Mn)). Mn and DOX concentrations were calculated using T1 relaxation times and Mn:DOX loading ratios, as previously described. Two independent validations by high‐performance liquid chromatography (HPLC) and histologic fluorescence in a rat fibrosarcoma (FSA) model indicate a concordant linear relationship between DOX concentrations determined using T1 and those measured invasively. This method of imaging exhibits potential for real‐time evaluation of chemotherapeutic protocols and prediction of tumor response on an individual patient basis. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.

Chemodosimetry of Invivo Tumor Liposome/Drug Concentration Using MRI

Biomedical Magnetic Resonance Imaging: Principles, Methodology, and Applications

There is great interest at present in incorporating image-management systems popularly referred to as picture archiving and communication systems (PACS) into imaging departments. This paper will describe various aspects of local area networks (LANs) for medical images and will give a definition of terms and classification of devices by describing a possible system which links various digital image sources through a high-speed data link and a common image format, allows for viewing and processing of all images produced within the complex, and eliminates the transport of films. The status of standards governing LAN and particularly PACS systems along with a proposed image exchange format will be given. Prototype systems, particularly a system for nuclear medicine images, will be presented, as well as the prospects for the immediate future in terms of installations started and commercial products available. A survey of the many questions that arise in the development of a PACS for medical images and also a survey of the presently suggested/adopted answers will be given.

Local area networks in an imaging environment.

Nuclear Medicine Annual 1989

The authors describe their 18 month experience operating an all digital nuclear medicine department, which led to the development of a system that allows multiple users to access patient reports and images through terminals located in various parts of the hospital. All user interactions are mediated through protocols that automatically acquire, process, display, and archive data. This approach offers distinct advantages over film and paper methods and is applicable in theory to any digital image format.

Modus operandi for a picture archiving and communication system.

A Nuclear Medicine Department has implemented a central computer system which stores all gamma camera images on hard disc. Multiple terminals allow simultaneous acquisition, processing and archiving of these images from various narts of the hospital. Downtime has been negligible and a month's work of patient studies is easily stored on line.

William A. Erdman

Papers

Biomedical Magnetic Resonance Imaging: Principles, Methodology, and Applications

Local area networks in an imaging environment.

Nuclear Medicine Annual 1989

Modus operandi for a picture archiving and communication system.

Development Of A Digital Nuclear Medicine System