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Current Medical
Imaging Reviews
ISSN: 1573-4056
Current Medical Imaging Reviews
Volume 3, Number 1, February
2007
Contents
Editorial Pp. 1
The Use of PET for Radiotherapy Pp.
3-16
Yusuf Emre Erdi
[Abstract] [Full
text article]
Renal Cell Cancer and Positron Emission Tomography-
an Evolving Diagnostic and Therapeutic Relationship
Pp. 17-26
Nathan Lawrentschuk, Damien M. Bolton, Ian D. Davis and
Andrew M. Scott
[Abstract] [Full
text article]
Diagnostic Methods in the Detection of Prostate Cancer:
Prospective Observational Study Pp. 27-35
Juan-Bosco Lopez-Saez, Milagros Otero, Margarita Dominguez
Villar, Antonio Lorenzo Peñuelas, Pedro Rodríguez
Navarro, Pedro Gallurt Moreira and Avelino Senra-Varela
[Abstract] [Full
text article]
Detection of Liver Metastases with Contrast Enhanced
Ultrasonography Pp. 37-44
Michele Bertolotto, Tommaso Vincenzo Bartolotta, Manuel
Belgrano, Elena Trincia, Stefano Cernic, Roberta Zappetti
and Maria Assunta Cova
[Abstract] [Full
text article]
Small Animal Computed Tomography Imaging
Pp. 45-59
Soenke H. Bartling, Wolfram Stiller, Wolfhard Semmler
and Fabian Kiessling
[Abstract] [Full
text article]
Percutaneous Laser Ablation of Small Hepatocellular
Carcinoma Pp. 61-65
Giampiero Francica and Claudio Maurizio Pacella
[Abstract] [Full
text article]
Facts and Artefacts in Bone Densitometry
Pp. 67-75
Gopinath Gnanasegaran, Glen M. Blake, Fiona M. Crane,
Dwight Dulnoan, Susan E. Clarke and Ignae Fogelman
[Abstract] [Full
text article]
Abstracts
[Back to top]
Editorial
Targeted Imaging-Guided Cancer Treatment,
Detection, and Artefacts of Bone Density Meassurement
Cancer remains one of the major causes of death in
the Western world, and it is increasing in developing countries
as well as in the industrial world. The overall costs of cancer
management relentlessly increase year on year. Therefore,
there are huge challenges ahead for all those involved in
the care of cancer patients that include the development of
new and more effective therapies and the development of new
technologies to diagnose cancer at an earlier stage, to define
the presence and extent of established tumors more accurately,
and to monitor new therapies directed at specific biological
targets. Imaging is now recognized as pivotal to the management
of cancer patients, and oncologic imaging is an increasingly
large component of the general workload in the radiologic
department.
The multichannel computed tomography (CT) is transforming
axial CT into a 3D modality, and the positron emission tomography
(PET) integrated with CT provides a precise tumor localization
combined with exquisite anatomical and morphological details.
The important development in ultrasonography is an introduction
of non-destructive microbubble contrast agents for enhancing
vascular structures or lesions.
In this issue there are seven excellent updated review articles
including three dealing with evaluation of various cancers
utilizing different imaging modalities (restaging renal cell
cancer with F-18 FDG PET, diagnosing prostate cancer in Spain
using color doppler ultrasonography and detection of hepatic
metastases with contrasted ultrasonography), one summarizing
use of micro-CT in basic animal research, one reporting safe
and effective laser thermal ablation (LTA) therapy of small
hepatocellular carcinoma, and one demonstarting variants and
artefacts of bone mineral density (BMT) study using dual-energy
X-ray absorptiometry (DEXA) which is widely used in clinical
practice for the management of osteoporosis. The demand for
BMD and physician visits related to osteoporosis has seen
a dramatic increase with a significant publicity. The precision
of DEXA analysis is what makes the technology such a clinically
useful tool.
The interpreter should be vigilant with regard to the proper
bone margins and the presence of mettallic hardware or artefacts.
Dr. E. Edmund Kim
(Editor-in-Chief)
Division of Diagnostic Imaging
The University of Texas M.D.
Anderson Cancer Center
Box59, 1515 Holcombe Blvd
Houston, TX 77030-4009
USA
Email: ekim@di.mdacc.tmc.edu
[Back to top]
The Use of PET for Radiotherapy
Yusuf Emre Erdi
[Full
text article]
The rapidly growing field of PET imaging is providing
new opportunities to define target volumes for radiotherapy.
For multiple disease sites, PET has become a tool to provide
a way to locate the most rapidly metabolizing portions of
the lesion mass and to detect unsuspected metastases over
conventional CT imaging. This made PET a desirable imaging
modality for radiotherapy treatment planning. In addition
to improved staging and target definition, radiotherapy has
benefitted from the use of PET as a therapy response tool.
Introduction of combined PET/CT units has accelerated the
proliferation of PET into treatment planning. Today there
are many radiation therapy departments either has a PET scanner
of their own or access to PET images. We are, now, in the
era of solving problems of PET imaging for smooth integration
into radiotherapy. However, in the future we will be beyond
hyper-metabolic tissue characterization and incorporation
of this information into functional treatment planning. New
lesion markers under development in animal models today will
inevitably be translated into clinical studies. With advances
in computer and biotechnology, in the near future, it may
be possible to give a cocktail of tracers to patients so as
to generate multi-dimensional information, to further improve
the radiobiological characterization of the target volume
for consideration in the radiation treatment planning. This
review provides an introduction to the subject of the use
of PET for radiotherapy for clinicians. It also outlines today’s
and tomorrows challenges for successful integration of PET
imaging into radiotherapy.
[Back to top]
Renal Cell Cancer and Positron Emission
Tomography- an Evolving Diagnostic and Therapeutic Relationship
Nathan Lawrentschuk, Damien M. Bolton, Ian D. Davis and
Andrew M. Scott
[Full
text article]
The incidence of Renal Cell Carcinoma (RCC) is increasing
at all stages. Thus, there is a need to develop more accurate
and reliable methods of diagnosing, staging and treating the
disease. The role of positron emission tomography (PET) is
still evolving with regard to the diagnosis, staging and management
of RCC. At present, the assessment of renal masses and primary
staging of RCC are reasonably well investigated using computed
tomography and ultrasound. However, many masses are still
excised that are benign or understaged. PET with 18F-Fluorodeoxyglucose
(FDG) has been useful with re-staging RCC and in certain cases
where conventional studies, including bone scan, are inconclusive.
The value of PET radiotracers in RCC other than FDG, the standard
one used in oncology, is under investigation. We review the
current status of PET in RCC and examine the recent development
of PET/CT with its impact on renal mass imaging due to its
ability to contemporaneously acquire and co-register data,
to localize elevated FDG uptake with improved anatomic specificity.
New radiotracers, such as those created by radiolabelling
of antibodies (e.g. labelled G250, a protein overexpressed
in RCC cells) and how they may impact on the diagnosis and
future treatment of RCC are also outlined.
[Back to top]
Diagnostic Methods in the Detection of Prostate
Cancer: Prospective Observational Study
Juan-Bosco Lopez-Saez, Milagros Otero, Margarita Dominguez
Villar, Antonio Lorenzo Peñuelas, Pedro Rodríguez
Navarro, Pedro Gallurt Moreira and Avelino Senra-Varela
[Full
text article]
Objective: The last decade has seen numerous modifications
in the way the prostate cancer is diagnosed. Current diagnostic
methods in prostate cancer lacking the ability to predict
individual patient outcome, which highlights the need for
more sensitive approaches. We investigated the value of digital
rectal examination (DRE), transrectal ultrasonography (TRUS)
and prostatic specific antigen (PSA) analysis as aids in general
clinical practice and in the early detection of prostate cancer.
The purpose of this paper is to evaluate the efficiency and
effectiveness of analytical and imaging methods for diagnosing
prostate cancer in the north-west Spain.
Material and Methods: We investigated prospectively two groups
of patients (in all 760) with pathological DRE or PSA. Sensitivity
(Se), specificity (Sp), Positive predictive Value (PPV), Negative
Predictive Value (NPV), Receiver Operating Characteristics
(ROC) curves and other analyses were performed to determine
the relative contributions of PSA, DRE, TRUS, Colour Doppler
Ultrasound (CDUS), symptoms and patient age to cancer prediction.
Results: The presence of prostatic disease symptoms did not
distinguish between subjects with and without cancer (p=0.8450).
The most sensitive (98%) was total PSA (>4 ng/ml) and the
most specific were DRE (78%) and TRUS (65%). The contribution
of PSA, DRE and TRUS to the diagnosis of prostate cancer was
significant (p<0.05). In patients with a PSA of 4-10 ng/ml,
using a threshold PSA specificity increased, using a free/total
PSA ratio of 15%. Both echographic methods were effective
(p<0.05), with greater specificity for CDUS.
Conclusion: The PSA continues to be the most sensitive method
for prostate cancer diagnosis. DRE tends to be more negative
at early stages of cancer detection. Comparing the conventional
TRUS echography with the CDUS, the latter is a better detector
in the diagnosis of cancer.
[Back to top]
Detection of Liver Metastases with Contrast Enhanced
Ultrasonography
Michele Bertolotto, Tommaso Vincenzo Bartolotta, Manuel
Belgrano, Elena Trincia, Stefano Cernic, Roberta Zappetti
and Maria Assunta Cova
[Full
text article]
Detection of liver metastases is one of the most common
problems in evaluating patients with primary neoplasms. Gray-scale
and color Doppler ultrasonography have limited accuracy with
a sensitivity ranging between 53% and 77%. Isoechoic metastases
and nodules under 1 cm in size may not be detectable. Occasionally,
non-metastatic liver lesions can be identified in neoplastic
patients which must be correctly characterized.
Microbubble contrast agents overcome many limitations of gray-scale
ultrasonography to detect liver metastases and increase the
possibility to differentiate them from other focal liver lesions.
In this review article we discuss the current role of contrast
enhanced ultrasonography in detection of liver metastases
using specialized destructive and non-destructive modes. Using
air-filled microbubbles and destructive modes the sensitivity
of contrast enhanced ultrasonography to detect liver metastases
ranges between 80% and 98%. The ease of use of the non-destructive
approach makes it much more attractive and is particularly
helpful for lesion characterization. An increasing number
of studies is being published regarding the diagnostic performance
of perfluorocarbon- or sulfur hexafluoride-filled microbubbles
with non-destructive modes to detect liver metastases, and
the general agreement is that sensitivity and specificity
of the non-destructive modes approach those of the destructive
approach and of helical CT.
[Back to top]
Small Animal Computed Tomography Imaging
Soenke H. Bartling, Wolfram Stiller, Wolfhard Semmler
and Fabian Kiessling
[Full
text article]
Micro Computed Tomography (micro-CT) was suggested in
biomedical research to investigate tissues and small animals.
Its use to characterize bone structures, vessels (e.g. tumor
vascularization), tumors and soft tissues such as lung parenchyma
has been shown. When co-registered, micro-CT can add structural
information to other small animal imaging modalities. However,
due to fundamental CT principles, high-resolution imaging
with micro-CT demands for high x-ray doses and long scan times
to generate a sufficiently high signal-to-noise ratio. Long
scan times in turn make the use of extravascular contrast
agents difficult. Recently introduced flat-panel based mini-CT
systems offer a valuable trade-off between resolution (~200
µm), scan time (0.5 s), applied x-ray dose and scan
field-of-view. This allows for angiography scans and follow-up
examinations using iodinated contrast agents having a similar
performance compared to patient scans. Furthermore, dynamic
examinations such as perfusion studies as well as retrospective
motion gating are currently implemented using flat-panel CT.
This review summarizes applications of experimental CT in
basic research and provides an overview of current hardware
developments making CT a powerful tool to study tissue morphology
and function in small laboratory animals such as rodents.
[Back to top]
Percutaneous Laser Ablation of Small Hepatocellular
Carcinoma
Giampiero Francica and Claudio Maurizio Pacella
[Full
text article]
Hepatocellular Carcinoma (HCC) arising in cirrhosis is
one of the most common malignant tumors in the world showing
wide geographical variations in prevalence. In this review
we will focus on Percutaneous Laser Ablation (PLA), the ablative
method of choice for HCC nodules (up to 4 cm) at our Institutions.
PLA was performed with a continuous-wave neodymium yttrium-aluminium-garnet
laser that operated at a wavelength of 1.064 µm. According
to lesion volume, one to four 300 ?m optic fiber (s) advanced
in 21-g needle were positioned into the target lesions under
US guide. A single optimal laser illumination was considered
when 1800 Joules/fiber were delivered in 6 min. at 5 W. The
interventional procedure was performed under conscious sedation,
on an inpatient basis. Spiral triphasic TC was used to assess
effectiveness of treatment.
According to our observation high rates of tumor necrosis
(90%) may be achieved in small HCC nodule (up to 4 cm) with
1 to 3 illuminations in 1 to 2 sessions.
In our study the mortality rate turned out to be 0.6% whereas
major complications occurred in 0.4% of cases.
Local tumor progression rate was of 15% and 49% respectively
patients who developed new lesions within five years of follow-up.
The 1-, 2-, 3-, 4-, and 5-year cumulative survival rates were
89%, 75%, 52%, 43%, and 27%, respectively. The independent
predictors of survival were found to be tumor grading, bilirubin
levels = 2.5 mg/dl and the achievement of complete tumor ablation.
On the other hand, complete necrosis could be achieved more
frequently due to some factors such as HCC grading (well differentiated
forms at histology), lesion location, easy to reach operator’s
skills and in case the HCC nodule was naïve (newly diagnosed
and not previously treated).
Our findings suggested that PLA is an effective and safe percutaneous
treatment modality for HCC nodules up to 4 cm.
[Back to top]
Facts and Artefacts in Bone Densitometry
Gopinath Gnanasegaran, Glen M. Blake, Fiona M. Crane,
Dwight Dulnoan, Susan E. Clarke and Ignae Fogelman
[Full
text article]
Measurement of bone mineral density (BMD) with dual-energy
X-ray absorptiometry (DXA) is widely used in clinical practice
for the diagnosis of osteoporosis and assessment of fracture
risk. However, variants and artefacts such as, osteophytes
and metallic objects can affect the BMD results of the spine
and hip. We demonstrate a spectrum of clinical examples that
may impact on BMD evaluation. Recognition of such artefacts
is important for the correct interpretation of these studies.
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