NLS-Method In Vascular Pathology Diagnosis
S.M. Patrushev,
A.D. Sluzky, V.M. Vagulin
Today the world faces a constant trend of a growing rate of mortality caused by occlusive
vascular diseases, especially by cerebro-vascular disorders which are in the third place
among death causes. On the one hand the trend is caused by a growing number of elderly
and aged patients. On the other hand many men even already at 45 have atherosclerotic
damage of main head arteries, causing the need for a medical observation.
The most simple and at the same time informative method of non-invasive diagnosis of
occlusive damage of peripheral vessels appeared to be the NLS-method which has been
used in clinical practice for a short time. The first NLS devices equipped with analog
trigger sensors, operating in 1.4 GHz frequency mode and used in clinical practice since
the late 90-s have not lost their importance yet. They can help determine the condition of
certain sections of the main vessels in the lower limbs and that of the brachio-caphalic
vessels.
Not only the condition of the vessels but also that of the valve system within deep veins
can be studied. 102 patients were examined in 1997-1998 to detect valve insufficiency of
deep veins affected by varicosis. The patients were from 21 to 67 years old. The
examined patients included 25 men (24.5%) and 77 women (75.5%). The study was
carried out by means of a NLS device using a 1.4GHz analog trigger sensor. In 32
patients a valve insufficiency of the femoral vein was detected, in 44 patients failure of
both femoral and popliteal veins. NLS enables to assess the condition of the valve
system of deep veins in low limbs on a noninvasive and objective basis. This enables
appropriate surgical intervention and can be used as an alternative to phlebography
analysis.
The NLS-digital spectral analysis method has no contra-indications and in terms of
informational content is comparable to angiography. It can be used to perform screening
in the course of poly-clinical examination with a view to detect early or latent forms of
vascular pathology and also as a preliminary method for selecting patients for angiosurgical treatment, since according to some specialists, angiography should only be
performed on candidates for surgery picked out after a preliminary NLS investigation.
However, this method does not assess the bulk index of the bloodstream, because NLS
does not provide a vessel’s image and thus is unable to measure the vessel’s diameter.
This kind of information may be acquired with the help of Doppler systems with 3Dimaging, that offer duplex and triplex scanning (the so-called Doppler chromatic
charting).
The NLS-method was developed in the mid 90-s and played an essential role in vascular
pathology diagnosis. The main advantage of the NLS-method was that it facilitated
search and location of the vessels and facilitated rapid differentiation of vessels from
nonvascular structures, arteries from veins and very accurate detection of signs of
19disturbed vascular permeability caused by stenosis or occlusion of the vessel lumen by an
atherosclerotic patch or a thrombus: both of which are generally not visible at scanning in
B-mode alone.
In addition the NLS-method enables diagnose of portal hypertension, the extent of its
intensity, and permeability of Porto systemic bypasses. NLS is very sensitive in defining the
extent of peri-pancreatic vessel involvement with pancreatic cancer: essential in
selecting the approach for surgical treatment. NLS facilitates detection of the damaged
renal vessels (both veins and arteries): invaluable for the correct choice of a hypotensive
drug at arterial hypertension.
Some efficient hypotensive drugs, i.e. inhibitors of angiotensin converting enzyme (ACE)
such as capoten, enalapril, bezlipril, etc., have became very popular lately, but they have
counter-indications at renal artery stenosis. So physicians should bear in mind that
checking for stenosis is a must before prescribing this kind of medicine. The NLSmethod is likely to be the choice method in such cases.
The NLS-method is indispensable for differential diagnosis of benign and malignant
hepatic diseases. Its sensitivity is comparable with the potentials of conventional or
digitial angiography and computer-assisted amplified tomography. In addition, the
NLSmethod is much cheaper, simpler and more intelligible. It can be employed directly at the
patient’s bedside if required. The NLS-method may be used in opthalmology to check ocular
hemodynamics before or after surgical intervention, in obstetrics to detect the disturbed
blood current in umbilical cord arteries with a view to diagnose a retarted
fetus development and predict a negative perinatal produce.
Yet another potential of NLS method lies in cranial scanning which enables to detect
intracranial hematomas, aneurisms, cysts and tumors in the encephalon.
These are far from all potentials of the NLS method.
Summing up, the NLS-method is one of the most dynamic techniques and within the next few
years it is bound to bring some new discoveries.