Diagnostic imaging of AIDS in China: current status and clinical application
LI Hong-jun
AIDS, Acquired Immunodeficiency Syndrome, has been a serious worldwide
problem threatening the health of human being. It has been listed as one of major
infectious diseases and is considered as the new plague of the 21st century. In China,
AIDS has a generally low prevalence, but a high prevalence in certain groups of
population and in some local areas, which constitutes a tough challenge for its
prevention and treatment. It was estimated that the global number of infected cases of
AIDS amount up to 33.2 million by the end of 2007; in the year of 2007, there has
been 2.5 million newly infected cases and death cases from AIDS were 2.1 million,
the newly infected having a daily mean increase of 7.4 thousand. The joint estimate
by Health Ministry of China, United Nations Programme on HIV and AIDS
(UNAIDS) and World Health Organization (WHO) showed that by the end of Dec.,
2007, the total cases of infected AIDS in China are about 0.7 million (ranging from
0.55-0.85 million), with a total infection rate of 0.05%. Efforts have been
continuously made to control the AIDS infected cases within 1.5 million by the year
of 2010. The severe challenge of preventing and treating AIDS has attracted extensive
attention from both the government and the public and it has been attached great
importance.
The keys for improving the therapeutic efficacy of AIDS and life quality of
AIDS patients are early identification of HIV carriers, advanced prevention of AIDS
complications and accurate diagnosis of AIDS. Therefore, diagnostic radiology has
been an irreplaceable role in the early diagnosis of AIDS complications. In recent
years, there has been a flood of research articles and monographs on AIDS related
complications approached through diagnostic radiology and its clinical application
and its application in basic medical science research have great achievements.
Essentialities of diagnostic imaging of AIDS
Due to the extremely compromised or even destroyed immune system of HIV
carriers, various pathogens take opportunities to invade, causing opportunistic
infections or related neoplasms to impair organs, with following occurrence of organ
failure or even death. Therefore, the complications of AIDS are the main causes of
death in AIDS patients.
Because of a lack of accurate diagnosis of AIDS complications, antibiotics is
unreasonably administered. Therefore, the diagnosis and the following treatment are
usually delayed to cause death.
No matter in specialised infectious diseases hospitals or general hospitals, AIDS
patients are usually found to know nothing about the 5 years to 10 years latency
period of AIDS after HIV infection, hospitalized till complications occur. Full
knowledge of AIDS complications spectrum by radiologists will facilitate their
identification of suspectabel HIV carriers and recommend further HIV detection,
which has great clinical significance. Thus, surgical plan alterations due to
preoperative HIV positive findings by immunological examinations can be avoided.
The value of diagnostic radiology in imaging diagnosis and differential diagnosis
of AIDS complications should not be underestimated.
Present imaging studies of AIDS
AIDS patients in China receive therapies mainly in primary hospitals of some
areas with insufficient techniques and facilities. The clinicians and radiologists
appreciate insufficient knowledge of AIDS radiology. In highly rated general hospitals,
HIV positive findings in routine tests before operations or before special examinations
cause reanalysis of imaging diagnosis. Therefore, it has been realized the importance
of adding AIDS radiology into our diseases spectrum of diagnostic radiology to avoid
missed diagnosis and misdiagnosis. On the basis of diseases spectrum of imaging
differential diagnosis, we should extend our thinking for backward reasoning of the
suspected HIV infected or AIDS cases who are unaware of their infection and
recommend clinical HIV detection. Therefore, widespread application of recent
achievements of AIDS radiology is important for spreading individualized therapy
and reasonably administering antibiotics. In developed countries of Europe and
America, the life quality of AIDS patients is close to that of the healthy population
and AIDS patients rarely die from AIDS complications. The death usually occurs due
to the naturally developed failure, which is closely related to how much the national
general therapeutic guideline of AIDS has put on the effective prevention and accurate
diagnosis of its complications. The treatment of AIDS includes 2 steps, firstly
antiviral therapy and then treatment of its complications. A scientific, general and
rigorous treatment should be planned according to the specific conditions of an
individual patient. And it should be advocated to use imaging techniques for early
diagnosis to decrease the occurrence of complications and death.
Complexity of AIDS complications radiology
Imaging demonstrations of AIDS complications are extremely complex and
characteristically include implications of one system or one organ during the whole
developing course of AIDS with occasional invasion of multiple systems, increased
occurrence of various pathogens infections with gradual decrease of immunity and
increase of survival period with multiple imaging demonstrations, the relationship
between diseases before HIV infection and newly occurred diseases after HIV
infection, the relationship between diseases caused by HIV infection and AIDS related
complications, imaging demonstration alterations before and after HAART therapy
for AIDS patients.
Classification of AIDS complications imaging
According to the causes of the disease, AIDS complications can be classified into
diseases caused by HIV infections, opportunistic infections and related neoplasms.
According to the focus of diseases, AIDS complications can be classified into nervous
system complications, respiratory system complications, ophthalmopathy
complications of eye sockets and ocular fundus, cardiovascular complications,
gastrointestinal complications, osteomuscular complications and skin complications.
Clinical applications of AIDS complications radiology
Inflammation, tuberculosis and neoplasms of AIDS related nervous system
complications can be diagnosed by Magnetic Resonance Imaging (MRI) and CT
scanning to define their location, size and range, and their qualitative diagnosis can be
made combined with immunologic indices or pathological analysis. Such diseases
include Herpes simplex virus encephalitis, CMV encephalitis, tuberculosis,
Toxoplasma gondii abscess and lymphoma. By comparing the natural density of the
lung by DR and CT scanning, the respiratory complications can be diagnosed, such as
pulmonary tuberculosis, fungal pneumonia, bacterial pneumonia, viral pneumonia,
protozoa (Karnofsky cysticercosis, Toxoplasma) pneumonia and KS sarcoma, which
can be diagnosed with AIDS complications radiology combined with laboratory and
biopsy findings. Ophthalmoscopy and fluorescein angiography (FFA) can be used to
define the location and range of ocular fundus diseases, combining with laboratory
findings. Gastrointestinal endoscopy and barium meal combined with biopsy could be
used to definitely diagnose such diseases as gastrointestinal fungal inflammation,
ulcers, tuberculosis, related lymphoma and KS sarcoma.
MRT has a widespread clinical application due to its excellent spatial resolution
in AIDS related inflammation of skeletal muscle and neoplasms.
Random movement of free water molecules is the underlying foundation of
Diffusion Weighted Imaging (DWI) which is highly dependent on its environment.
Diffusion degree of tissues is directly influenced by the shape, size, arrangement,
location and permeability of histocytes, as well as extracellular space and cellular
liquid. Different diffusion occurs with variations in tissues, such as swollen or
destroyed cells, abnormal changes of nucleolus, permeability of cells and distribution
of intracellular and extracellular fluid. Besides, ACD value differs in AIDS related
neoplasms and inflammation, proving differential diagnosis.
Demonstrations
reflected in DWI spectrum assist doctors in differential diagnosis of benign or
malignant transformation of AIDS related neoplasms. For example, increase of Cr and
decrease of NAA shown in MR spectrum indicate an infectious disease. Such
demonstrations can also district consolidation of sac of tumor and edema areas around
the tumor; by detecting ADC value and metabolic rate such as Cho／Cr, NAA／Cr,
NAA／Cho in brain parenchyma, doctors can evaluate imaging diagnosis ,differential
diagnosis and therapeutic efficacy; DWI can as well correctly define AIDS related
cerebral infraction.
PWT, through imaging mode of MRT, demonstrates condition of horizontal
blood perfusion of capillary, evaluating viability and function of local tissues in
regards to MRT. Therefore, evaluation on hemodynamics in capillary vessel of
AIDS related brain diseases can be made.
DIT is a new MRI technology developed in recent years, with a growing clinical
application and scientific research on pathological changes of alba overseas.
Research papers on large samples of clinical application on DIT are hardly seen in
China, but early diagnosis can be realized by determining the FA value and its
influences on the boundaries of white matter fasciculus, the pathological parts of
AIDS related brain diseases, as well as how it is pressed and displaced around
neoplasms.
PET (WB-DWI), classified as MR, can evaluate forms and functions of all
lymph notes in AIDS patients, define the primary and metastasis of AIDS related
malignant neoplasms and estimate its therapeutic efficacy. However, it enjoys
limited clinical application in China with insufficient researches, and further studies
are needed to appreciate more information about it.
PET-CT or PET-MR is combination of PET imaging and CT scanning or MR
imaging, simultaneously mirroring the pathological and psychological variations and
morphological structures of the nidus. Therefore, reference of treatment can be
reached with the located and qualitative diagnosis, apparrantly increasing accuracy in
diagnosis and rationality in treatment. There are some research articles and
monographs on AIDS related diseases abroad, in which differential diagnosis of AIDS
related nervous system infections and related neoplasms are highly appreciated, such
as differential diagnosis of cerebral toxoplasmosis, lymphoma, body-related infectious
diseases, neoplasms and assessment on forms and functions of all lymph notes in
AIDS patients.
Clinical applications of new imaging technologies in the future
With the development of imaging technologies, people obtain a more objective,
impressive and obvious understanding about diseases and their causes. Such new
technologies are ESysfMRI and DynaSuite applied in nervous system, Torso Coil
used to effectively diagnose pathological variation in body organs in the future, Breast
Coil and DynaCAD with a more accurate diagnosis and individualized puncture
therapy of breast diseases, and so forth. The aforementioned scientific researches
will be gradually popularize through clinical applications, facilitating early diagnosis
and differential diagnosis in a convenient, quick, and accurate way based on series of
functions of MR. Thus, nowadays, the new imaging technologies represent the
highest in its field, a perfect combination of functional imaging and anatomic imaging,
an advocacy in modern technologies of imaging diagnosis.
The specialty topics concerns with AIDS complications spectrum and their
characteristic imaging demonstrations in MRI are reported as the references to
specialists of this field. We hope it can drive the widespread clinical applications of
AIDS complications radiology, promote awareness of AIDS complications spectrum
and better clinical diagnosis and differential diagnosis.
Chair of Chinese Association of STD & AIDS Prevention, Care and treatment
working committees and AIDS Clinical Imaging Group
Director of Department of Diagnostic Radiology, Affiliated Beijing You’an
Hospital, Capitcal Medical University
Supported by National funding project, Special Supported Project of National
Eleventh five years for major infectious diseases. No. 2008ZX10001-006
Correspondence to: Professor Li Hong-jun, with specialty in Diagnostic Imaging
of Infectious Diseases and the pathological basic research of Infectious Diseases.
E-mail:lihongjun00113@126.com, Tel: 010-83997337