Preface: Diffusion Imaging: From Head to Toe ................... xi
L. Celso Hygino Cruz
Basic Concepts of MR Imaging, Diffusion MR Imaging, and
Diffusion Tensor Imaging ........................................ 1
Eduardo H.M.S.G. de Figueiredo, Arthur F.N.G. Borgonovi,
and Thomas M. Doring
MR image contrast is based on intrinsic tissue properties and
specific pulse sequences and parameter adjustments. A growing
number of MRI imaging applications are based on diffusion
properties of water. To better understand MRI diffusion-
weighted imaging, a brief overview of MR physics is presented
in this article followed by physics of the evolving techniques
of diffusion MR imaging and diffusion tensor imaging.
Diffusion MR Imaging in Central Nervous System ................. 23
Claudio de Carvalho Rangel, L. Celso Hygino Cruz Jr., Tatiana
Chinem Takayassu, Emerson L. Gasparetto, and Romeu Cortes
Domingues
Diffusion-weighted imaging has been used extensively in
clinical practice for the early diagnosis of central
nervous system conditions that restrict the diffusion of
water molecules because it provides information about
tumor cellularity or abscesses containing viscous fluid.
DTI can detect brain lesions before any conventional
imaging. Even though the role of these modalities is well
defined for many neurologic lesions that affect the
brain, its clinical application in spinal cord diseases
is increasing. This article discusses the several central
nervous system conditions that may be diagnosed with
diffusion imaging.
Diffusion Magnetic Resonance Imaging in the Head and Neck ...... 55
James Schaf er, Ashok Srinivasan, and Suresh Mukherji
Diffusion weighting (DW) represents a magnetic resonance
imaging contrast distinct from T1 and T2 in terms of
imaging physics and its relationship to underlying
physiology and pathophysiology. DW imaging has become
a sine qua non of neuroimag-ing because of its exquisite
sensitivity to the molecular motion of water that is
altered in many pathologic conditions including acute
ischemia. This article reviews the physical principles of
DW imaging in the head and neck and describes how it can
help to solve this and several other related problems.
Diffusion-Weighted Imaging of the Chest ........................ 69
Antonio Luna, Javier Sanchez-Gonzalez, and Pilar Caro
Diffusion-weighted imaging (DWI) is feasible in the chest
with currently available MR imaging scanners, although it
is technically demanding. Although there is scarce
clinical experience, the use of DWI has shown promising
results in the characterization of pulmonary nodules, in
lung cancer characterization and staging, and in the
evaluation of mediastinal and pleural pathology. Ongoing
research opens a door to noninvasive evaluation of heart
fibers by means of diffusion-tensor imaging. Another area
under investigation is the use of DWI of hyperpolarized
gases as an early biomarker of pulmonary disease.
Diffusion Magnetic Resonance Imaging of the Breast ............. 95
Fernanda Philadelpho Arantes Pereira, Gabriela Martins,
and Raquel deVasconcellos Carvalhaes de Oliveira
Several studies have investigated the role of advanced
magnetic resonance imaging (MRI) techniques, such as
diffusion-weighted imaging (DWI), to improve the
specificity of MRI for the evaluation of breast lesions.
Potential roles for DWI and the apparent diffusion
coefficient in characterizing breast tumors and
distinguishing malignant from benign tissues have been
reported. This article discusses the clinical applications
of breast DWI, including literature results, technical
issues and limitations, and the potential applications.
The analysis of DWI at our institution is also discussed.
The establishment of standard DWI protocols and diagnostic
criteria is necessary to ensure accuracy and reproducibility
at different centers.
Diffusion-Weighted Magnetic Resonance Imaging in the Upper
Abdomen: Technical Issues and Clinical Applications ........... 111
Leonardo K. Bittencourt, Celso Matos, and Antonio
C. Coutinho Jr.
Recent technological achievements have enabled the
transposition of diffusion-weighted imaging (DWI) with good
diagnostic quality into other body regions, especially the
abdomen and pelvis. Many emerging and established
applications are now being evaluated on the upper abdomen,
the liver being the most studied organ. This article
discusses imaging strategies for DWI on the upper abdomen,
describes the clinical protocol, and reviews the most
common clinical applications of DWI on solid abdominal
organs.
Pelvic Applications of Diffusion Magnetic Resonance Images .... 133
Antonio C. Coutinho Jr., Arun Krishnaraj, Cintia E. Pires,
Leonardo K. Bittencourt, and Alexander R. Guimarães
Diffusion-weighted imaging (DWI) is a powerful imaging
technique in neuroimaging; its value in abdominal and
pelvic imaging has only recently been appreciated as
a result of improvements in magnetic resonance imaging
technology. There is growing interest in the use of DWI for
evaluating pathology in the pelvis. Its ability to
noninvasively characterize tissues and to depict changes at
a cellular level allows DWI to be an effective complement to
conventional sequences of pelvic imaging, especially in
oncologic patients. The addition of DWI may obviate contrast
material in those with renal insufficiency or contrast
material allergy.
Diffusion-Weighted Magnetic Resonance Imaging for the
Evaluation of Musculoskeletal Tumors .......................... 159
Flávia Martins Costa, Elisa Carvalho Ferreira, and Evandro
Miguelote Vianna
Conventional MR imaging provides low specificity in the
differential diagnosis of musculoskeletal (MSK) tumors and
is unable to offer information about the extent of tumoral
necrosis and the presence of viable cells, information
crucial to assess treatment response and prognosis.
Therefore, diffusion-weighted imaging (DWI) is now used
with conventional MR imaging to improve diagnostic
accuracy and treatment evaluation. This article discusses
the technical aspects of DWI, particularly the quantitative
and qualitative interpretation of images in MSK tumors.
The clinical application of DWI for tumor detection,
characterization, differentiation of tumor tissue from
others, and assessment of treatment response are emphasized.
sion MR Imaging for Monitoring of Treatment Response .......... 181
Anwar R. Padhani and Dow-Mu Koh
Functional imaging techniques are increasingly being used to
monitor response to therapies, often predicting the success
of therapy before conventional measurements are changed.
This review focuses on magnetic resonance imaging (MRI)
depicted water diffusivity as a tumor response parameter.
Response assessments are undertaken by noting changes in
signal intensity on high b-value images or by using
measurements of apparent diffusion coefficient values. The
different diffusion-weighted (DW)-MRI appearances in
response to treatment of soft tissue
disease and bone metastases are discussed. DW-MRI changes
observed in response to cytotoxics, radiotherapy,
antiangiogenics, embolization, and thermocoagulation are
detailed.
Index ......................................................... 211
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