U.S. patent application number 12/119921 was filed with the patent office on 2008-10-23 for monitoring conditions of a patient's urinary system.
This patent application is currently assigned to P. SQUARE MEDICAL LTD.. Invention is credited to Ori SAHAR, Menashe SHAHAR.
Application Number | 20080262389 12/119921 |
Document ID | / |
Family ID | 38189078 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080262389 |
Kind Code |
A1 |
SHAHAR; Menashe ; et
al. |
October 23, 2008 |
MONITORING CONDITIONS OF A PATIENT'S URINARY SYSTEM
Abstract
A monitoring system and method are presented for use in
monitoring a condition of a patient's urinary system. The
monitoring system comprises an acoustic assembly comprising at
least one acoustic receiver adapted for continuously receiving
acoustic signals during a patient's urination and generating data
indicative thereof. The monitoring system also includes a control
unit that is in communication with said acoustic assembly. The
control unit is configured and operable for analyzing said
generated data indicative of the continuously received acoustic
signals during a patient's urination, obtaining a time variation of
the acoustic signal during the urination and determining a
corresponding spectral data of the acoustic signal. The control
unit further analyzes the spectral data and, upon detecting at
least one first signal peak corresponding to a condition of
turbulence in the urine flow, determining a relation between said
first signal peak and a second signal peak corresponding to a
condition of laminar urine flow. Based on said relation, the
control unit determines the condition of a patient's low urinary
system and generating output data indicative thereof.
Inventors: |
SHAHAR; Menashe; (Korazim,
IL) ; SAHAR; Ori; (Korazim, IL) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
P. SQUARE MEDICAL LTD.
Yorkneam
IL
|
Family ID: |
38189078 |
Appl. No.: |
12/119921 |
Filed: |
May 13, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/IL2006/001463 |
Dec 20, 2006 |
|
|
|
12119921 |
|
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Current U.S.
Class: |
600/586 |
Current CPC
Class: |
A61B 7/04 20130101; A61B
7/026 20130101; A61B 5/4381 20130101; A61B 5/208 20130101; A61B
2562/0204 20130101 |
Class at
Publication: |
600/586 |
International
Class: |
A61B 7/00 20060101
A61B007/00; A61B 5/00 20060101 A61B005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2005 |
IL |
172754 |
Claims
1. A monitoring system for use in monitoring a condition of a
patient's urinary system, the monitoring system comprising: (a) an
acoustic assembly comprising at least one acoustic receiver adapted
for continuously receiving acoustic signals during a patient's
urination and generating data indicative thereof; and (b) a control
unit in communication with said acoustic assembly, the control unit
being configured and operable for analyzing said generated data
indicative of the continuously received acoustic signals during a
patient's urination, obtaining a time variation of the acoustic
signal during the urination and determining a corresponding
spectral data of the acoustic signal, analyzing the spectral data
and, upon detecting at least one first signal peak corresponding to
a condition of turbulence in the urine flow, determining a relation
between said first signal peak and a second signal peak
corresponding to a condition of laminar urine flow, and based on
said relation determining the condition of a patient's low urinary
system and generating output data indicative thereof.
2. The system of claim 1, wherein said spectral data includes a
Strouhal frequency range.
3. The system of claim 1, wherein said spectral data includes a
frequency range of about 20-1000 Hz.
4. The system of claim 1, wherein the second signal peak
corresponding to condition of laminar urine flow is in a frequency
range of 70-150 Hz.
5. The system of claim 1, wherein the first signal peak
corresponding to the turbulent urine flow is in a frequency range
of 150-1000 Hz.
6. The system of claim 1, wherein the control unit is configured
and operable for analyzing the spectral data by determining a time
variation of the relation between the first and second signal
peaks, a frequency of at least the first signal peak varying with
time during the urination.
7. The system of claim 1, wherein the control unit is configured
and operable to determine the relation between the first and second
signal peaks by calculating at least one of the following: a ratio
between amplitudes of the first and second signals, and a ratio
between frequencies of the first and second signals, and time
variations of these ratios during urination and/or during
successive urinations.
8. The system of claim 1, wherein the control unit comprises a
memory utility for storing reference data comprising a given value
or a range of values for at least one of the following parameters:
an urethral diameter, urethral length, and elasticity of an
urethral wall.
9. The system of claim 1, wherein the control unit is configured
and operable to apply a predetermined model to the spectral data,
said model being based on a given value or a range of values for at
least one of the following parameters: an urethral diameter,
urethral length, and elasticity of an urethral wall.
10. The system of claim 1, wherein the control unit is configured
and operable to process and analyze the relation between the first
and second signals or a time variation of the relation between the
first and second signals during the urination, and calculate or
estimate at least one of the following parameters indicative of the
urinary system condition: amount of urinated urine during the
urination time; urinal flow velocity profile; urinary flow rate;
urethral obstruction degree; pressure in urinary bladder; and
detrusor pressure.
11. The system of claim 1, comprising a positioning unit for
positioning said at least one acoustic receiver in the vicinity of
the patient's urine flow such that an acoustic interface of the
receiver is in a position for receiving acoustic signals generated
during the patient's urination.
12. A method for use in monitoring a condition of a patient's
urinary system, the method comprising: (a) continuously detecting
acoustic signals originated by urine flow during the patient's
urination, and generating data indicative thereof; (b) analyzing
said data generated during the urination and determining spectral
data indicative thereof; (c) analyzing the spectral data and, upon
detecting at least one first signal peak corresponding to a
condition of turbulence in the urine flow, determining a relation
between said signal peak corresponding to the condition of
turbulence in the urine flow and a second signal peak corresponding
to a condition of laminar urine flow, and using said relation to
determine the condition of a patient's urinary system and generate
output data indicative thereof.
13. The method of claim 12, wherein said continuous detection of
the acoustic signals is carried out by at least one acoustic
receiver.
14. The method of claim 12, wherein said spectral data includes a
Strouhal frequency range.
15. The method of claim 12, wherein said spectral data includes a
frequency range of about 20-1000 Hz.
16. The method of claim 12, wherein the signal peak corresponding
to a condition of laminar urine flow is in a frequency range of
70-150 Hz.
17. The method of claim 12, wherein the signal peak corresponding
to the turbulent urine flow is in a frequency range of 150-1000
Hz.
18. The method of claim 12, wherein said analyzing of the spectral
data comprising determining a time variation of the relation
between the first and second signal peaks.
19. The method of claim 12, wherein said relation between the first
and second signal peaks is indicative of at least one of the
following: a ratio between amplitudes of the first and second
signals, and a ratio between frequencies of the first and second
signals.
20. The method of claim 12, wherein said analyzing of the spectral
data comprises applying to said data a predetermined model based on
a given value or a range of values for at least one of the
following parameters: an urethral diameter, urethral length, and
elasticity of an urethral wall.
21. The method of claim 12, wherein said output data indicative of
the condition of the urinary system comprises at least one of the
following: amount of urinated urine during the urination time,
urinal flow velocity profile, urinary flow rate, urethral
obstruction degree, urethral flow resistance, pressure in urinary
bladder and detrusor pressure.
22. A diagnostic kit for use in monitoring a condition of a
patient's urinary system configured and operable according to the
method of claim 12.
23. A method for use in monitoring a condition of a patient's
urinary system, the method comprising: analyzing spectral data
corresponding to acoustic signals originated by urine flow during
the patient's urination; and upon detecting at least one first
signal peak corresponding to a condition of turbulence in the urine
flow, determining a relation between said first signal peak and a
second signal peak corresponding to a condition of laminar urine
flow; and using said relation to determine the condition of a
patient's urinary system and generate output data indicative
thereof.
24. A computer system adapted for receiving data indicative of a
sequence of acoustic signals each corresponding to continuous
measurement during a respective urination time, said computer
system being configured and operable for processing said data to
determine spectral data corresponding to each of the acoustic
signals, analyzing the spectral data and, upon detecting at least
one first signal peak in the acoustic signal corresponding to a
condition of turbulence in the urine flow, determining a relation
between said first signal peak and a second signal peak in said
acoustic signal corresponding to a condition of laminar urine flow,
and based on said relation generating output data indicative of a
condition of a patient's urinary system from which said acoustic
signals have been originated.
Description
FIELD OF THE INVENTION
[0001] This invention is generally in the field of medical devices,
and relates to a device and method for monitoring conditions of a
patient's urinary system.
BACKGROUND OF THE INVENTION
[0002] Monitoring of a condition of a patient's urinary system is
needed for detecting various types of the urine system abnormality,
including inter alia prostate enlargement. The latter is a
widespread phenomenon developed in more than half men over age 50.
By age 80, about 80% of men have enlarged prostates. The prostate
enlargement is thought to be related to hormonal disorders typical
to the age, and is termed Benign Prostatic Hyperplasia or BPH. In a
minority of the cases, the prostate enlargement involves prostate
cancer.
[0003] Whatsoever be the cause, enlarged prostate may lead to
bladder control problems. This is because the prostate gland
encircles the urethra beneath the bladder neck. An enlarged
prostate exerts pressure on the urethra which may deform its shape
and reduce its cross sectional area. In acute circumstances, a
total obstruction of the urethra might occur.
[0004] A quantitative diagnosis of the urethral condition, such as
urethral obstruction, can help in early detection of prostate
problems, which in turn allows for anticipating medication or other
appropriate treatment. In cases where bladder control problems
exist already, a quantitative diagnosis may help in determining
severity of the case and in monitoring the effect of the treatment
procedures been taken.
[0005] From a broader perspective, a quantitative diagnosis of
urethral obstruction is only one of several common tests taken
during the somewhat complicated process of screening and diagnosing
for Lower Urinary Tract Symptoms (LUTS). Lower Urinary Tract
Symptoms may involve several factors, including disorders in the
somatic nervous system, in the bladder/urethral autonomic nervous
system, in the detrusor and in the sphincter muscles, and more.
Said screening process is therefore a must for distinguishing
between the plurality of medical situations that may cause a
patient to experience urinary problems.
[0006] Facilitating and simplifying the recognition and the
quantitative diagnosis of urethral condition may therefore be
essential not only in case an obstruction does exist, but also in
negating its existence in the opposite case thus leading toward a
correct diagnosis.
[0007] The methods commonly used for quantitative detection of
urethral and prostate conditions include the following techniques:
a digital rectal exam to feel for prostate enlargement; cystoscopy
(under local anesthetic) consisting of passing a lens into the
urethra and bladder to examine if any abnormalities are present;
intravenous pyelogram consisting of X-ray irradiation of the
urinary tract as a dye is injected into a vein that shows up tumors
or obstructions; transrectal ultrasonography that uses a rectal
probe for assessing the prostate; transabdominal ultrasonography
that uses a device placed over the abdomen; and urodynamic
technique including measurements of a urine flow speed
(uroflowmetry) for quantitative detection of urethral, bladder and
prostate conditions. The latter test, however, cannot determine the
cause of obstruction, which can be due not only to BPH, but
possibly also to abnormalities in the urethra, weak bladder
muscles, or other causes.
[0008] Various techniques have been developed, for determining the
prostate related conditions, based on acoustic methods. These
techniques are disclosed for example in the following patents and
patent publications: U.S. Pat. No. 6,063,043; U.S. Pat. No.
6,428,479; WO 05/067392; WO 05/004726; and RU 2224464.
[0009] WO 07/072484, by the inventors of the present application,
discloses a system and method for the determination of urethral
blockage, utilizing a transducer arrangement for locating in the
vicinity of the patient's urine flow, and a control unit in
communication with the transducer arrangement. The transducer
arrangement has at least one acoustic transducer capable of at
least receiving acoustic waves, generated by the patient's urine
flow, and producing an output signal indicative thereof. The
control unit receives and processes the output signal and
determines a change in the output signal indicative of the urethral
blockage.
GENERAL DESCRIPTION
[0010] There is a need in the art for a novel technique for
non-invasive instant indication of parameters indicative of a
patient's urinary system condition (in particular, urinal flow
velocity profile, urethral obstruction degree, pressure in urinary
bladder and detrusor pressure), capable of shortening and
facilitating the process of screening and diagnosing for Lower
Urinary Tract Symptoms (LUTS), even before any physical symptoms
have actually been experienced by the patient.
[0011] The currently used non-invasive methods are practically
incapable of determining an urethral obstruction or performing a
quantitative measurement thereof. As mentioned above, uroflowmetry
can not necessarily teach of the obstruction and/or of its severity
unless the internal bladder pressure is also known. This is because
on the one hand a low urinary flow rate may be an indication of a
detrusor problem rather than of an urethral obstruction, while on
the other hand a normally detected flow rate should not necessarily
indicate of a normal urethra since it may result from extra
abdominal/bladder pressures compensating against certain flow
resistance caused by urethral obstruction. Uroflowmetry combined
with simultaneous measurement of internal bladder pressure is thus
required in order to allow for discrimination between the different
factors (i.e. the urethra flow resistance and the abdominal/bladder
pressure). Internal bladder pressure measurement involves however
invasive procedure--inserting a catheter into the bladder. The
inconvenience and infection risks accompanied to the procedure make
its use rare and appropriate for special cases only.
[0012] The present invention takes advantage of the fact that a
urine flow generates acoustic signals of unique Strouhal
frequencies, and provides a novel technique based on continuous
measuring and analyzing these acoustic signals and extracting data
indicative of various parameters characterizing the patient's
urinary system condition. These parameters include an urination
time, amount of urinated urine, urinal flow velocity profile,
urinary flow rate; urethral obstruction degree, pressure in urinary
bladder and detrusor pressure from a patient. In particular, the
urethral obstruction causes a turbulent-like urine flow through the
urethra, which is of a differing nature than that of laminar-like
urine flow in a non-obstructed urethral part. The inventors have
found that such a turbulence-like flow of the urine generates
additional acoustic signals in the Strouhal frequencies' range.
Accordingly, the recognition of signals typical to a turbulent-like
flow is indicative of the obstructed urine flow through the
urethra, the frequency and magnitude of which may be indicative of
the obstruction range and of the distance between the transducer
interface and the obstruction's location.
[0013] It should be understood that the expressions
"turbulent-like" or "turbulent" and "laminar-like" or "laminar"
used herein to describe the urine flow behavior, refer to the urine
flows which, while being not absolutely turbulent and laminar,
differ from one another towards respectively turbulence and laminar
behavior of the flow.
[0014] According to the invention, acoustic signals are
continuously detected during the patient's urination and data
indicative of these acoustic signals is analyzed. The data analysis
comprises determination of spectral data indicative of the
continuously detected acoustic signals, and further analysis of
this spectral data to identify whether the spectral data includes
at least one first signal peak corresponding to a condition of
turbulence in the urine flow. In case such a first peak exists, a
relation between this first signal peak and a second signal peak
corresponding to a condition of laminar urine flow is determined.
Based on the so-determined relation, the condition of a patient's
urinary system can be determined and output data indicative thereof
can be generated.
[0015] The present invention, according to its one broad aspect,
provides a monitoring system for use in monitoring a condition of a
patient's urinary system. The monitoring system comprises at least
one acoustic receiver adapted for continuously detecting acoustic
signals during the patient's urination and generating data
indicative thereof; and a control unit in communication with the
acoustic receiver(s). The control unit is configured and operable
for analyzing said generated data. This is aimed at determining
spectral data indicative of the acoustic-signals data, and further
analyzing the spectral data. Upon detecting at least one first
signal peak corresponding to a condition of turbulence in the urine
flow, a relation between said first signal peak and a second signal
peak corresponding to a condition of laminar urine flow. Based on
said relation, the condition of a patient's urinary system can be
determined and output data indicative thereof can be generated.
[0016] When desired, the monitoring system can comprise a
positioning unit for positioning said at least one acoustic
receiver in the vicinity of the patient's urine flow such that an
acoustic interface of the receiver is in a position for receiving
acoustic signals generated during the patient's urination.
[0017] According to some embodiments of the present invention, the
spectral data includes a Strouhal frequency range which can be
determined in a frequency range of about 20-1000 Hz. The first
signal peak corresponding to the turbulent urine flow can be
detected in a frequency range of 150-1000 Hz. The second signal
peak corresponding to condition of laminar urine flow can be
detected in a frequency range of 70-150 Hz.
[0018] According to an embodiment of the present invention, the
control unit is configured and operable for analyzing the spectral
data by determining a time variation of the relation between the
first and second signal peaks, the first signal peak varying with
time during the urination. More specifically, both peaks move
towards higher frequencies when the flow becomes to be
stronger.
[0019] When desired, the control unit is configured and operable to
determine the relation between the first and second signal peaks by
calculating at least one of the following: a ratio between
amplitudes of the first and second signals, and a ratio between
frequencies of the first and second signals, and time variations of
these ratios during urination and/or during successive urinations.
In operation, the control unit is configured and operable to
calculate or estimate also one or more following parameters
indicative of the urinary system condition: amount of urinated
urine during the urination time, urinal flow velocity profile,
urinary flow rate; urethral obstruction degree, urethral flow
resistance, pressure in urinary bladder and detrusor pressure.
[0020] According to an embodiment of the present invention, the
control unit comprises a memory utility for storing reference data
comprising a given value or a range of values for at least one of
the following parameters: an urethral diameter, urethral length,
and elasticity of an urethral wall. When desired, the control unit
can be also configured and operable to apply a predetermined model
to the spectral data. This model can be based on a given value or a
range of values for one or more of the above-defined
parameters.
[0021] The present invention, according to another broad aspect,
provides a method for use in monitoring a condition of a patient's
urinary system. The method comprises continuously detecting
acoustic signals originated by urine flow during the patient's
urination, and generating data indicative thereof. These data
generated during the urination are analyzed and corresponding
spectral data is generated and analyzed to thereby, upon detecting
at least one first signal peak corresponding to a condition of
turbulence in the urine flow, determine a relation between said
signal peak corresponding to the condition of turbulence in the
urine flow and a second signal peak corresponding to a condition of
laminar urine flow. Using said relation, the condition of a
patient's urinary system is determined and output data indicative
thereof is generated.
[0022] According to some embodiments of the present invention, this
continuous detecting the acoustic signals can be carried out by one
or more acoustic receivers.
[0023] According to one embodiment of the present invention, there
is provided a diagnostic kit for use in monitoring a condition of a
patient's urinary system that is configured and operable according
the above-described method.
[0024] According to another general aspect of the present
invention, there is provided a method for use in monitoring a
condition of a patient's urinary system. The method comprises
analyzing spectral data corresponding to acoustic signals
originated by urine flow during the patient's urination; and upon
detecting at least one first signal peak corresponding to a
condition of turbulence in the urine flow, determining a relation
between said first signal peak and a second signal peak
corresponding to a condition of laminar urine flow; using said
relation to determine the condition of a patient's urinary system
and generate output data indicative thereof.
[0025] According to yet another general aspect of the present
invention, there is provided a computer system adapted for
receiving data indicative of a sequence time and date of acoustic
signals. This computer system is configured and operable for
processing said data to determine spectral data indicative thereof,
analyzing the spectral data and, upon detecting at least one first
signal peak corresponding to a condition of turbulence in the urine
flow, determining a relation between said first signal peak and a
second signal peak corresponding to a condition of laminar urine
flow. Based on said relation, the computer system generates output
data indicative of a condition of a patient's urinary system from
which said acoustic signals have been originated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to understand the invention and to see how it may
be carried out in practice, embodiments will now be described, by
way of non-limiting example only, with reference to the
accompanying drawings, in which:
[0027] FIG. 1 is a block diagram of an example of a monitoring
system of the present invention for monitoring a condition of a
patient's urinary system;
[0028] FIG. 2 is an example of the configuration and operation of
the monitoring system of FIG. 1;
[0029] FIG. 3 is a flow diagram of an example of a method of the
present invention for use in the determination of the condition of
a patient's urinary system; and
[0030] FIG. 4A is an example of quantitive measurement of sound
urine flow using the method of the present invention;
[0031] FIG. 4B is an example of quantitive measurement of sound
urine flow by the conventional uroflowmeter; and
[0032] FIG. 5 is a nomogram illustrating how the method of the
present invention is used for the spectral analysis of Strouhal
frequency ranges as function of the urine flow in patients with
diagnosed bladder outlet (urethral) obstructions and in patients
from a control group (with no bladder outlet obstructions).
DETAILED DESCRIPTION OF EMBODIMENTS
[0033] The principles of the technique of the present invention may
be better understood with reference to the drawings and the
accompanying description, wherein like reference numerals have been
used throughout to designate identical elements. It should be
understood that these drawings, which are not necessarily to scale,
are given for illustrative purposes only, and are not intended to
limit the scope of the invention.
[0034] Referring to FIG. 1, there is illustrated, by way of a block
diagram, a monitoring system 10 of the present invention for
monitoring a condition of a patient's urinary system. The
monitoring system 10 includes an acoustic assembly 12 including one
or more acoustic elements that is/are capable of at least receiving
acoustic waves and generating data indicative thereof, and a
control unit 14 that is configured and operable for receiving and
analyzing the data indicative to the acoustic waves received by the
acoustic receiver assembly 12. The connection between the acoustic
receiver assembly 12 and the control unit 14 is provided via wires
or wireless signal transmission. In the latter case, the acoustic
receiver assembly and the control unit are appropriately provided
with communication utilities for transmitting and receiving IR, RF
or acoustic data signals.
[0035] As indicated above, the acoustic receiver assembly 12
includes one or more acoustic receivers. These may be microphones
or accelerometers. The acoustic receiver may be directly positioned
in the vicinity of a region of interest on the patient's body or
may be carried by an appropriately designed positioning unit. Such
an acoustic receiver can be configured to provide an analog
electrical output, or may be equipped with an analog-to-digital
converter thus providing digital output indicative of the received
acoustic waves. The acoustic assembly 12 is preferably a disposable
part of the monitoring system, intended for single measurement or
to present the so-called "holter monitor" for continuous
monitoring.
[0036] In operation, the acoustic receiver assembly 12 can be
connected to the input of an amplifier (not shown), the output of
which can be connected to the control unit 14. It should be
understood that amplifier can alternatively be a constructional
part of the control unit.
[0037] The control unit 14 is typically a computer system having
inter alia a memory utility 16 (for storing certain reference data
as will be described further below), a data processing and
analyzing utility 17, and any data presentation utility such as,
for example, a display 18. The data processing and analyzing
utility 17 is preprogrammed with a predetermined algorithm for
analyzing data indicative of acoustic waves and generating output
data about the corresponding urinary system condition.
[0038] Reference is made to FIG. 2, showing a specific but not
limiting example of the configuration and operation of the
monitoring system 20 for monitoring a condition of a patient's
urinary system. The exemplified system 20 includes an acoustic
assembly (12 in FIG. 1), which in the present example of FIG. 2 is
formed by a single acoustic receiver 21 (microphone) that is
positioned on the patient's body in the vicinity of a region of
interest, i.e., in the vicinity of a urine flow region of an
urethra 25 in a penis 24. A control unit 14 is connectable e.g. via
wire 23 to the acoustic receiver 21. It should be understood that
the acoustic assembly may include more than one acoustic
receiver.
[0039] The system 20 operates as follows: After the acoustic
receiver 21 is held in place, the patient is requested to urinate,
and the acoustic receiver 21 continuously receives acoustic waves
produced by the urine flow during the urination time. The acoustic
receiver output (in the analogue or digital representation) is
transmitted to the control unit 14 where the corresponding data
indicative of the time variation of the acoustic signal during the
urination time is recorded. It should be noted that the acoustic
assembly itself may be equipped with an appropriate utility
(software and/or hardware) for recording the acoustic data. The
control unit 14 operates to process and analyze the acoustic data,
to obtain and display information indicative of the urine flow in
view of the corresponding condition of the urinary system organs
such as the urethra 25 and urinary bladder 26, and a prostate gland
28.
[0040] FIG. 3 shows a flow diagram 30 of a method according to an
example of the present invention for use in the determination of
the condition of a patient's urinary system. As shown in this
specific but not limiting example, certain reference data may be
provided (step 301) and stored in a memory utility of the control
unit. The reference data may include a given value or a range of
values for at least one of the following parameters: an urethral
diameter, urethral length, and elasticity of an urethral wall
previously obtained for the monitored patient or estimated based on
the patient's personal data and relevant statistics. The reference
data may be obtained by carrying out preliminary measurements. For
example, the urethral diameter can be measured using one of X-ray,
MRI or various ultrasound methods. Flow velocity can be measured,
in particular, by using uroflowmetry, ultrasound based
measurements, electromagnetic based measurements or any other
technique for measuring urine flow In addition, the reference data
may include relevant data and/or models for healthy patients and
patients with various different diseased conditions. Preferably,
the reference data includes one or more from the above indicated
parameters for different groups of patients, for example of
different ages. However, these parameters are known to be varied
from individual to individual within small ranges, i.e. with no
more than about 15% difference between the lower and upper values
of the range.
[0041] Acoustic data from a specific patient is collected (step
302). This data corresponds to the acoustic waves continuously
generated during the patient's urination. In other words, the
acoustic data includes an acoustic wave amplitude as a function of
time. In case multiple acoustic receivers are used, such data may
include a single time function from all the receivers, determined
by summation or averaging, or a plurality of such time functions,
the entire data thus being a function of coordinate (acoustic
receiver location) and time.
[0042] The so measured data (time function of acoustic signal) is
spectrally analyzed to determine a frequency profile for the
received signal (step 303), resulting in the acoustic signal as a
function of both, the time and frequency. Specifically,
identification of acoustic signals relating to the urination
process itself and time-points of the urination initiation and
ending can be provided by spectral analysis of the acoustic signals
and their intensities. The acoustic spectrum of the urine flow is
different from acoustic spectra of other body signals, and thus the
urination signals can be detected even in highly rustled
conditions.
[0043] In operation, the acoustic signals may be transmitted to the
control unit in an analog form and then converted to a digital
sequence of amplitude versus time vector or such conversion is
implemented in the acoustic assembly (step 304). As indicated
above, the signal may be transmitted as an electrical signal via
wire or as an RF, IR or acoustic signal via wireless signal
transmission. Optionally, such a time function of the acoustic
signal can be subject to further signal processing, e.g. an FFT
(Fast Fourier Transform) in order to extract frequency and phase
from each received signal.
[0044] Then, the control unit operates to process and analyze the
so-determined spectral data (steps 305, 306). More specifically,
this processing is based on the following:
[0045] The information relating to the urine flow and relevant
processes occurring in the urinary system can be identified and
interpreted from the spectral behavior of the acoustic data,
including the Strouhal frequency range, which is of about 10-1000
Hz. During the fluid flow in a urethra, a sound is generated with
one or more characteristics maxima in its spectrum at a Strouhal
frequency, and also outside this range. The Strouhal frequency
range, F.sub.S, can be expressed by the following relationship:
F.sub.S=K.sub.SV/D,
where V is a flow velocity, D is an urethral diameter, and K.sub.S
is the Strouhal Coefficient which has a value of 0.15-0.2 and can
be precisely calculated using the Reynolds number which
characterizes the flow regime. The Reynolds number appropriate for
the urethral flow is estimated as
Re=DV/.nu.,
where .nu. is a dynamic viscosity of the fluid.
[0046] The range of Reynolds numbers corresponding to a laminar
flow of the fluid along a channel is known as being about
2,000-2,300 (the value of the Strouhal coefficient at these
Reynolds numbers is .about.0.1-0.15, while a turbulent flow can be
described by Reynolds numbers in a range of about 3,000-30,000.
Reynolds numbers in a range of about 2,300-3,000 describe a flow
that has features of both laminar and turbulent flows
(corresponding to Strouhal coefficient of about 0.2). Acoustic
signal peaks at frequencies outside the Strouhal range could also
appear in an acoustic signal recorded during the urine flow through
the urethra. These peaks are associated with effects of urethral
diameter, urethral length, and urethral perimeter on the urine flow
and accordingly on the corresponding acoustic waves. Relating to
the male urethra, the effect of the urethral diameter corresponds
to the ultrasound domain of frequencies, and that of the urethral
length--to the frequencies above 4 KHz.
[0047] The acoustic signal peaks (resonances) caused by affect of
the elasticity of the pipe's wall onto the urine flow behavior
should preferably also be taken in account. The wall elasticity
related resonance can be estimated using a spring-mass model with
the following parameters: fluid's density, .rho., that is equal to
1000 Kg/m.sup.3, and a tissue's Young's Modulus, E, that is
equalized to around 104-105 Pa. With regard to the mass density in
the model (that accounts for tissue and fluid mass) it is equal to
approximately 2-3 g/cm.sup.2 (or 20-30 Kg/m.sup.2). The
relationship between the mass and the spring's elasticity in the
model leads to resonant frequencies of a few tens of Hertz, which
are slightly dependant on the inner diameter of the pipe.
[0048] The actual wall elasticity in the urethra varies to some
degree with the advance along the urethra's axis, together with the
typical pressures in each cross-section. In the most proximal part
of the urethra, i.e. nearest to the bladder outlet, the static
pressure is higher than at more distal cross-sections, and the
Young's Modulus is also higher. Accordingly, during the urination,
the resonant frequency in the corresponding acoustic signal changes
along the urethra, and is higher at its beginning and lower at the
end. Thus, the acoustic signal amplitude might increase at a
certain frequency range with respect to the position along the axis
and the static pressure at that cross-section.
[0049] Thus, acoustic signals indicative of the urine flow
condition are mainly the Strouhal range. This is because the
urethra's diameter generally does not vary more than 25% along the
urethra, and the diameter dependant frequencies (which as mentioned
above are outside the Strouhal range) thereby do not vary more than
25%. That is the reason that the Strouhal-frequency signals are
expected to be more dominant than the other signals, which do vary
locally as explained above.
[0050] Referring back to FIG. 3, one or more signal peaks
corresponding to condition of a laminar (or laminar-like) urine
flow in a frequency range of 70-150 Hz can be detected (step 305).
Such laminar urine flow is indicative of the urine flow in
non-obstructed parts of the urethra, and would therefore always
appear in the received acoustic signals, irrespective of whether
the urinary system condition is normal or not. The signals related
to the laminar flow can be used, in particular, for analysis of
amount of urinated urine and urinal flow velocity, using the above
equations.
[0051] The urethral obstruction (e.g. by an enlarged prostate)
causes a turbulent or turbulent-like urine flow through the
urethra, which is of a differing nature than that of laminar urine
flow. Such a turbulence flow of the urine generates additional
acoustic signals in a frequency range (e.g., 150-1000 Hz) different
from that of the laminar flow. Accordingly, the recognition of
acoustic signals typical to a turbulent flow is indicative of the
urine flow obstruction through the urethra (step 306).
[0052] The inventors have found that a relation between the first,
laminar flow related peak and the second, turbulent flow related
peak (i.e. the frequency and/or magnitude of such peaks in the
acoustic signal) is indicative of the obstruction range and of the
distance between the acoustic receiver interface and the
obstruction's location. This relationship is also indicative of a
urinary flow rate. The flow rate can be calculated using reference
data (such as the urethral diameter in one or more parts of the
urethra, urethral length and elasticity of an urethral wall) (step
307). Also, the flow rate can be estimated from the acoustic
measurements: both peaks move towards higher frequencies when the
flow becomes to be stronger and move towards lower frequencies when
the flow becomes weakly. Accordingly, the spectral analysis
preferably covers a frequency range that exceeds the range of
70-150 Hz.
[0053] Thus, the relation between the signal peaks indicative of
the laminar and turbulent flows can provide data indicative inter
alia of main obstruction diameter (step 308). This relation can be
calculated as at least one of the following: a ratio between
amplitudes of the first and second peaks, a ratio between
frequencies of the first and second peaks, and time variations of
these ratios during urination and/or during successive
urinations.
[0054] More specifically, the relation between the urethral part
obstructed by the prostate and the unobstructed parts of the
urethra by measuring the Strouhal frequencies can be described in
the following manner. The Strouhal frequency in the obstructed
parts can be calculated by the following relationship:
F.sub.1=0.2V.sub.1/D.sub.1,
and correspondent Strouhal frequency for unobstructed parts is
F.sub.2=0.2V.sub.2/D.sub.2.
[0055] If the flow volume Q is constant, then
Q=V.sub.1S.sub.1=V.sub.2S.sub.2,
where
S=.pi.D.sup.2/4
is the cross sectional area.
[0056] Therefore,
V.sub.1D.sub.1.sup.2=V.sub.2D.sub.2.sup.2, or
V.sub.1/V.sub.2=(D.sub.1/D.sub.2).sup.2.
[0057] As it was described above, the relation between the first
and second peaks can be indicative of a relation between the
obstructed and non-obstructed urethral diameters. The following
relations can be obtained from previous expressions:
F.sub.1/F.sub.2=C.sub.0=V.sub.1D.sub.2/V.sub.2D.sub.1=(V.sub.1/V.sub.2)/-
(D.sub.1/D.sub.2).
[0058] This relation can be rewritten as following:
V.sub.1/V.sub.2=C.sub.0D.sub.2/D.sub.1.
[0059] Using expression V.sub.1/V.sub.2=(D.sub.1/D.sub.2).sup.2
mentioned above, following relation can be obtained:
C.sub.0=(D.sub.2/D.sub.1).sup.3.
or, in other words, the ratio of the diameters in the unobstructed
and obstructed parts of the urethra is proportional to the inverse
ratio between the first and second Strouhal frequency peaks to the
power of three.
[0060] Turning back to FIG. 3, the control unit operates to
determine the urethral obstruction degree (step 309) using the
above ratio of the diameters in the unobstructed and obstructed
parts of the urethra. The urethral obstruction degree corresponds
to an urethral flow resistance.
[0061] Further, the technique of the present invention allows for
determining the total value of a urinal pressure in whole urethra
as well as in any of its part (step 310).
[0062] The urinal pressure, P.sub.d, can be calculated by the
following relationship:
P.sub.d=hpg/1000,
where h is a head loss (estimated in meters), p is a fluid density
(kg/meters.sup.3) and g is a gravitational acceleration
(meter/sec.sup.2). In its turn, the head loss h can be calculated
as follows:
h=f(L/d)(.nu..sup.2/2g),
where f is a friction factor, L is an urethral length, d is an
urethral diameter, .nu. is a velocity of the fluid (meter/sec) and
g is the gravitational acceleration. The urethral length, the
urethral diameter and the velocity of the fluid can be obtained
from the reference data or preliminary measured by any suitable
method. The friction factor can be estimated from Reynolds number
which is calculated as described hereinbefore. If Reynolds numbers
are less than 2300 (i.e., the urine flow is laminar), the friction
factor equals to 64/Re. When the urine flow is turbulent (i.e., Re
is higher than 3,000), the friction factor can be calculated by the
following relationship:
1/f.sup.2=-1.8 log[(6.9/Re)+((k/3.7).sup.1.11)],
where k is the relationship between an urethral roughness and the
urethral diameter.
[0063] Respectively, calculation of a ratio of the urinal pressures
in the unobstructed and obstructed parts of the urethra can be
performed by using values of the urethral obstruction degree and
the reference data such as the urethral diameter, urethral length,
and elasticity of an urethral wall (step 311). A sum of the urinal
pressures in the unobstructed and obstructed parts of the urethra
is indicative to the total value of a urine pressure, which can
thus be determined.
[0064] The total urine pressure is dependent, inter alia, on amount
of the urine in the bladder and on characteristics of the bladder
muscles. An effect of each of these parameters on the urinary
system condition is associated with the following: the pressure of
the muscles is occasional (i.e., during the urination) and the
pressure of the urine in the bladder has a continuous feature.
Therefore, a possible method to distinguish between these
parameters' effects is by measuring the urination during very short
time periods (for example, in a range of 0.1-0.5 milliseconds), in
which change of the muscle pressure is neglected, but change of the
urinary flow rate are significant.
[0065] Based on the above processing of the acoustic data in the
form of time variation of acoustic signals during the urination
time, the present invention provides output data indicative of the
urinary system's condition (step 312). The output data can include,
but not limited to, the amount of urinated urine, urinal flow
velocity, urinary flow rate, urethral obstruction degree, detrusor
pressure and pressure in urinary bladder. The output data can be
compared to the reference data and the comparison results, being
indicative of the existence of physiological abnormalities and the
degree of pathology, are displayed to the user, who may be a
physician or the patient himself.
[0066] Reference is now made to FIGS. 4-5 showing the experimental
results of using the technique of the present invention and
corresponding reference methods for examining data indicative of
the urinary system's condition.
[0067] FIGS. 4A and 4B show quantitive measurements of the urinary
flow rate by using, respectively, the acoustic measurements of the
present invention and by the commonly used method, i.e.
uroflowmeter. As it can be understood from these figures, the
urinary flow profile measured according to the method of the
present invention and that measured by the uroflowmeter are highly
correlated (the graphs are found to be coincident). Moreover, the
calculated data of a maximal urinary flow rate (Qmax) and an
average urinary flow rate (Qavg) are found to be very similar.
[0068] FIG. 5 shows a nomogram obtained by the technique of the
present invention and illustrating the highest acoustic signal peak
in a frequency range of 10-1000 Hz at a time point of the maximal
urinary flow rate (Qmax) as a function of the Qmax (calculated in
cubic centimeters (or milliliter) per second) in patients with
previously diagnosed bladder outlet obstructions and in patients
from a control group with no bladder outlet obstructions. In these
experiments, 19 patients (ages 34-87, marked by white highlight
color) with diagnosed bladder outlet obstructions or with boundary
between the normal and obstructed conditions and 15 patients (ages
20-37, marked by black highlight color) from the control group have
been examined. As it can be clearly seen from FIG. 5, peak
frequencies higher than 200 Hz in the acoustic signals related to
the turbulent flow of the urine, indicative of the urine flow
obstruction and relatively high detrusor pressure (marked as Pdet
high), were found for 14 patients (all with diagnosed bladder
outlet obstructions). In addition, peaks of the acoustic signal in
a frequency range of 150-200 Hz related to the boundary between the
normal and obstructed conditions (i.e. that can equivocally be
indicative of the urine flow obstruction) were observed in 4
patients (all diagnosed with boundary between the normal and
obstructed conditions). Finally, the existence of only the peak
frequencies related to a laminar urine flow (70-150 Hz) and thus to
the unobstructed flow and relatively normal/low detrusor pressure
(marked as Pdet normal) were found in all 15 patients from the
control group.
[0069] However, it should be noted that the existing urological
approach is to consider the obstructed state in patients if they
are characterized by high detrusor or bladder pressure and low
urinary flow rate. The technique of the present invention allows
for statistical examination of the high detrusor or bladder
pressure (i.e., obstructed condition) in patients in which, for
example, the determined acoustic peak at a frequency higher than
200 Hz corresponds to Qmax that is less than 10 cc/sec. In
contrast, non-obstructed (healthy) state can be diagnosed in
patients in which 70-150 Hz acoustic peak is corresponding to Qmax
higher than 10 cc/sec.
[0070] Those skilled in the art to which the present invention
pertains, can appreciate that while the present invention has been
described in terms of preferred embodiments, the conception, upon
which this disclosure is based, may readily be utilized as a basis
for the designing of other structures systems and processes for
carrying out the several purposes of the present invention.
[0071] In the method claims that follow, alphabetic characters used
to designate claim steps are provided for convenience only and do
not imply any particular order of performing the steps.
[0072] Also, it is to be understood that the phraseology and
terminology employed herein are for the purpose of description and
should not be regarded as limiting.
[0073] Finally, it should be noted that the word "comprising" as
used throughout the appended claims is to be interpreted to mean
"including but not limited to".
[0074] It is important, therefore, that the scope of the invention
is not construed as being limited by the illustrative embodiments
set forth herein. Other variations are possible within the scope of
the present invention as defined in the appended claims.
* * * * *