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Ultrasonic appearances associated with prostatic inflammation: A preliminary study
ClinicalRadiology (1984) 35,343-345 © 1984 Royal College of Radiologists
0009-9260/84/318343502.0C
Ultrasonic Appearances Associated with Prostatic Inflammation" A Preliminary Study G. J. GRIFFITHS, A. J. R. CROOKS*, E. E. ROBERTS?, K. T. EVANS~, A. C. BUCK+, P. J. THOMAS§ and W. B. PEELING§
Department of Diagnostic Radiology, Royal Gwent Hospital, Newport, Gwent," *Department of Genito-urinary Medicine, Cardiff Royal Infirmary; t Department of Diagnostic Radiology, Welsh National School of Medicine; Departments of Urology, $ Cardiff Royal Infirmary and § St Woolos Hospital, Newport, Gwent Per-rectal ultrasonography was performed on 40 patients in whom a diagnosis of prostatitis had been made on the basis of symptoms and signs of prostatic inflammation confirmed by bacteriology, microscopy or pH changes of expressed prostatic secretion. Certain ultrasonic features were present in all patients to a variable degree. A change in volume and weight of the prostate could be an indicator of treatment response.
In recent years per-rectal ultrasound examination of the prostate has come to be recognised as a valuable technique to assist in the differential diagnosis of prostatic disease (Watanabe et al., 1980; Brooman et al., 1981a; Braeckman and Denis, 1983; Peeling and Griffiths, 1984). Although established ultrasonic criteria help to differentiate benign hyperplasia and carcinoma, confusion still exists in the accurate differentiation between early confined cancer and inflammatory disease. Our experience with per-rectal ultrasound of approximately 1300 scans from 900 patients has suggested that there may be features typical of prostatic inflammation which are unlike the appearances of confined carcinoma. Therefore, a prospective study was planned to examine the ultrasonic characteristics of a group of patients with a clinical diagnosis of prostatic inflammation and this report presents preliminary findings which are of interest. PATIENTS AND METHODS
A prospective study was conducted on 40 patients considered to have symptoms and signs of prostatic inflammation. Twenty-four were initially seen by genito-urinary physicians and 16 by urological surgeons. The mean age of the patients was 34 years (range 17-68 years) and their symptoms were mostly dysuria, sometimes with perineal pain, testicular pain or lower backache, but 19 of those referred by the department of genito-urinary medicine had had an urethral discharge. Each patient underwent a full clinical examination, including digital examination of the prostate to assess its size, consistency and degree of tenderness. When an urethral discharge was present it was examined microscopically and cultured for the usual pathogens and chlamydia trachomatis. Objective evidence of prostatic inflammation was sought in all patients either by voided segmented urinary stream studies (Stamey, 1980) or by examination of expressed prostatic secretion (Blacklock, 1981). All patients underwent per-rectal ultra-
sound scanning of the prostate by an Aloka chairmounted probe coupled to a Searle Phosonic static scanner using procedures previously described by our group (Brooman et al., 1981b). A follow-up ultrasonic scan was carried out in 36 patients, 5-24 weeks after their initial examination (mean 12 weeks) and during this period they had received treatment with antibiotics for prostatic inflammation. The volume of the prostate in every patient was determined from each sequential scan using serial planimetry facilitated by a microprocessor incorporated within the static scanner. Consequently, it was possible to compare any change in volume which might have occurred following treatment.
RESULTS OF ULTRASONIC STUDIES 1. Ultrasonic Characteristics
The ultrasonic features of the normal prostate are well known (Fig. 1) (Peeling et al., 1979; Gammelgaard and Holm, 1980; Watanabe et al., 1980). In this study patients with prostatitis had three main ultrasonic features which differed from the appearances of the normal gland. These were as follows. 1. A low-amplitude or echo-free halo around a slightly echogenic central area was seen in the periurethral zone of the prostate (Fig. 2). 2. Multiple low-amplitude regions in the peripheral zone of the prostate (Fig. 3). The prostatic capsule was ill defined. 3. Curvitinear, tubular echo-free regions immediately adjacent to the prostate extending from its anterior aspect around its lateral margins (Fig. 4). A periurethral low-amplitude or echo-free halo was present in all 40 patients (100%) in this study; peripheral zone low-amplitude regions were noted in 32 patients (80%), whereas tubular echo-free areas adjacent to the capsule were present in eight patients (20%). 2. Volumetric Studies
There appeared to be no overall change in the prostatic volume in association with treatment for prostatic inflammation because the mean percentage volume change measured in 36 patients was only 5%. However, when the patients were separated into two groups dependent on their clinical response to treatment, it became evident that there was a difference in
344
CLINICAL R A D I O L O G Y
Fig. 1 - Per-rectal ultrasonic scan of a normal prostate which has a crescent shape. The capsule is intact, appearing as a continuous line (arrows) and the internal echoes are, in gcneral, homogeneous. The ultrasonic transducer is seen posteriorly in the rectum.
Fig. 2-Per-rectal ultrasonic scan demonstrating the periurethral glandular and stromal tissue as a low-amplitude halo around a central echogenic area (arrows).
p r o s t a t i c m e a s u r e m e n t s . T h o s e p a t i e n t s (26) c o n s i d e r e d on clinical g r o u n d s to h a v e i m p r o v e d in r e s p o n s e to antibiotic treatment showed a mean percentage volume reduction of t h e p r o s t a t e of 16% ( r a n g e 7 - 3 5 % ) , w h e r e a s those with no e v i d e n c e of a clinical r e s p o n s e (14) h a d a m e a n v o l u m e increase of 13% ( r a n g e
3-35%).
DISCUSSION It is often difficult to d i f f e r e n t i a t e b a c t e r i a l a n d
Fig. 3-Per-rectal ultrasonography showing a heterogeneous echo pattern in the gland parenchyma due to multiple low-amplitude areas (arrows). The prostatic capsule is ill-defined.
Fig. 4 - Per-rectal ultrasonic scan demonstrating curvilinear, echo-free tubular areas adjacent to the prostate and extending from the anterior region of the gland around its lateral margins (arrows). There are also low-amplitude regions seen in the posterior part of the peripheral zone and surrounding the urethra, which is now lying near the centre of the gland.
n o n - b a c t e r i a l p r o s t a t i t i s f r o m a small, c o n f i n e d prostatic c a n c e r on digital e x a m i n a t i o n a l o n e (Jewitt, 1956). Until r e c e n t l y , it was c o n s i d e r e d difficult to d i f f e r e n t i a t e by p e r - r e c t a l u l t r a s o u n d b e t w e e n p r o s t a t i c calculi, bacterial a n d n o n - b a c t e r i a l p r o s t a t i t i s and c o n f i n e d p r o s t a t i c carcinoma. Recent experience indicates that prostatic calculi h a v e an easily i d e n t i f i a b l e a p p e a r a n c e on u l t r a s o u n d ( H a r a d a et al., 1979; P e e l i n g a n d Griffiths, 1984), but it is still difficult to d i f f e r e n t i a t e ultrasonically b e t w e e n i n f l a m m a t o r y d i s e a s e of t h e p r o s t a t e and p r o s t a t i c c a n c e r b e c a u s e b o t h c o n d i t i o n s can c r e a t e similar u l t r a s o n i c a p p e a r a n c e s ( H a r a d a et al., 1979;
ULTRASOUND IN PROSTATIC INFLAMMATION
Resnick, 1980). Therefore, any additional ultrasonic features which can support a diagnosis of inflammatory prostatic disease would be a welcome development to differentiate between benign and malignant disease and should increase the probability of accurate diagnosis made on the basis of the ultrasonic features. The exact morphology of the three ultrasonic features is uncertain. The commonest feature in patients with prostatitis was the demonstration of the periurethral glandular and stromal tissue as a low-amplitude halo around a central echogenic area. We have seen this appearance in all proven cases of bacterial and non-bacterial prostatitis and we believe this might be a valid sign of prostatitis. However, others (Harada et al., 1980) only noted this appearance in 50% of their cases of prostatitis and also commented that it was visualised in 69% of normals. The specificity of this sign should, therefore, remain under review for the present. The next most frequent ultrasonic feature in these patients was a heterogeneous echo pattern with multiple areas of low-amplitude echoes in the gland parenchyma. Occasionally, these coalesce to involve larger areas of the gland. These appearances might represent multiple focal areas of prostatic infection. When present, the prostatic capsule was usually ill-defined. The least common pattern was the appearance of curvilinear echo-free tubular areas adjacent to the prostate, extending from the anterior regions of the gland around its lateral margins. It is possible that these appearances were due to engorged and prominent veins in the prostatic venous plexus secondary to prostatic inflammation. Although the prostatic venous plexus may often be demonstrated during per-rectal ultrasonography, we only saw prostatic veins with this degree of prominence in patients with prostatic inflammation. It is of considerable interest that there was evidence of reduction of volume of the prostate in patients who had experienced a satisfactory response to treatment and it might be significant that not one patient in this group showed an increase of volume. This contrasts with the observations that the volume and weight remained unchanged or increased if there had been no improvement in symptoms following treatment. It has been shown (Carpentier et al., 1982; Peeling, 1983) that, in the treatment of prostatic cancer, volume reduction mirrors response to endocrine treatment and, therefore, can be used to monitor response to treatment. Hence, it is possible that a change in volume and weight of the prostate might also be an indicator of treatment
32
345
response in patients with prostatitis, although ultrasonically there was little change in the other features of prostatitis in our patients following a mean interval of observation of 12 weeks. Acknowledgements. The authors gratefully acknowledge the assistance of the Department of Medical Illustration, Royal Gwent Hospital, Newport in preparing the figures and Miss Janet Owen for typing the manuscript.
REFERENCES Blacklock, N. J. (1981). Prostatis - pathogenesis, clinical features and management. In RecentAdvaces in Urology/Andrology, No. 3, pp. 185-197. Churchill Livingstone, Edinburgh. Braeckman, J. & Denis, L. (1983). The practice and pitfalls of ultrasonography in the lower urinary tract. European Urology, 9, 193-201. Brooman, P. J. C., Peeling, W. B., Griffiths, G. J., Roberts, E. E. & Evans, K. T. (1981a). A comparison between digital examination and per-rectal ultrasound in the evaluation of the prostate. British Journal of Urology, 53, 617-620. Brooman, P. J. C., Griffiths, G. J., Roberts, E. E., Peeling, W. B. & Evans, K. T. (1981b). Per-rectal ultrasound in the investigation of prostatic disease. Clinical Radiology, 32, 669-676. Carpentier, P. J., Schroder, F. H. & Blom, J. H. M. (1982). Transrectal ultrasonography in the follow-up of prostatic carcinoma patients. Journal of Urology, 128, 742-746. Gammelgaard, J. & Holm, H. H. (1980). Transurethral and transrectal ultrasonic scanning in urology. Journal of Urology, 124, 863-868. Harada, K., Igani, D. & Tamahashi, Y. (1979). Gray scale transrectal ultrasonography of the prostate. Journal of Clinical Ultrasound, 7, 45-49. Harada, K., Tamahashi, Y., Igani, D., Numata, I. & Orikasa, S. (1980). Clinical evaluation of inside echo patterns in gray scale prostatic echography. Journal of Urology, 124, 216-220. Jewitt, H. J. (1956). Significance of the palpable prostatic nodule. Journal of the American Medical Association, 160, 838-839. Peeling, W. B. (1983). Castration for prostatic carcinoma still an alternative form of treatment? In Androgens and Anti-androgens, ed. Schroder, F. H., pp. 127-128. Weess, Schering Nederland. Peeling, W. B., Griffiths, G. J., Evans, K. T. & Roberts, E. E. (1979). Diagnosis and staging of prostatic cancer by transrectal ultrasonography. A preliminary report. British Journal of Urology, 51, 565-569. Peeling, W. B. & Griffiths, G. J. (1984). Clinical staging of prostatic cancer. In Urology, Vol. 2, The Prostate, Butterworths International Medical Reviews. Butterworths, London (in press). Resnick, M. (1980). Ultrasound evaluation of the prostate and bladder. Seminars in Ultrasound, 1, 69-79. Stamey, T. A. (1980). Pathogenesis and Treatment of Urinary Tract Infections, pp. 1-51. Williams and Wilkins, Baltimore. Watanabe, H., Date, S., Ohe, H., Saitch, M. & Tanaka, S. (1980). A survey of 3000 examinations by transrectal ultrasonotomography. The Prostate, 1,271-278.
0009-9260/84/318343502.0C
Ultrasonic Appearances Associated with Prostatic Inflammation" A Preliminary Study G. J. GRIFFITHS, A. J. R. CROOKS*, E. E. ROBERTS?, K. T. EVANS~, A. C. BUCK+, P. J. THOMAS§ and W. B. PEELING§
Department of Diagnostic Radiology, Royal Gwent Hospital, Newport, Gwent," *Department of Genito-urinary Medicine, Cardiff Royal Infirmary; t Department of Diagnostic Radiology, Welsh National School of Medicine; Departments of Urology, $ Cardiff Royal Infirmary and § St Woolos Hospital, Newport, Gwent Per-rectal ultrasonography was performed on 40 patients in whom a diagnosis of prostatitis had been made on the basis of symptoms and signs of prostatic inflammation confirmed by bacteriology, microscopy or pH changes of expressed prostatic secretion. Certain ultrasonic features were present in all patients to a variable degree. A change in volume and weight of the prostate could be an indicator of treatment response.
In recent years per-rectal ultrasound examination of the prostate has come to be recognised as a valuable technique to assist in the differential diagnosis of prostatic disease (Watanabe et al., 1980; Brooman et al., 1981a; Braeckman and Denis, 1983; Peeling and Griffiths, 1984). Although established ultrasonic criteria help to differentiate benign hyperplasia and carcinoma, confusion still exists in the accurate differentiation between early confined cancer and inflammatory disease. Our experience with per-rectal ultrasound of approximately 1300 scans from 900 patients has suggested that there may be features typical of prostatic inflammation which are unlike the appearances of confined carcinoma. Therefore, a prospective study was planned to examine the ultrasonic characteristics of a group of patients with a clinical diagnosis of prostatic inflammation and this report presents preliminary findings which are of interest. PATIENTS AND METHODS
A prospective study was conducted on 40 patients considered to have symptoms and signs of prostatic inflammation. Twenty-four were initially seen by genito-urinary physicians and 16 by urological surgeons. The mean age of the patients was 34 years (range 17-68 years) and their symptoms were mostly dysuria, sometimes with perineal pain, testicular pain or lower backache, but 19 of those referred by the department of genito-urinary medicine had had an urethral discharge. Each patient underwent a full clinical examination, including digital examination of the prostate to assess its size, consistency and degree of tenderness. When an urethral discharge was present it was examined microscopically and cultured for the usual pathogens and chlamydia trachomatis. Objective evidence of prostatic inflammation was sought in all patients either by voided segmented urinary stream studies (Stamey, 1980) or by examination of expressed prostatic secretion (Blacklock, 1981). All patients underwent per-rectal ultra-
sound scanning of the prostate by an Aloka chairmounted probe coupled to a Searle Phosonic static scanner using procedures previously described by our group (Brooman et al., 1981b). A follow-up ultrasonic scan was carried out in 36 patients, 5-24 weeks after their initial examination (mean 12 weeks) and during this period they had received treatment with antibiotics for prostatic inflammation. The volume of the prostate in every patient was determined from each sequential scan using serial planimetry facilitated by a microprocessor incorporated within the static scanner. Consequently, it was possible to compare any change in volume which might have occurred following treatment.
RESULTS OF ULTRASONIC STUDIES 1. Ultrasonic Characteristics
The ultrasonic features of the normal prostate are well known (Fig. 1) (Peeling et al., 1979; Gammelgaard and Holm, 1980; Watanabe et al., 1980). In this study patients with prostatitis had three main ultrasonic features which differed from the appearances of the normal gland. These were as follows. 1. A low-amplitude or echo-free halo around a slightly echogenic central area was seen in the periurethral zone of the prostate (Fig. 2). 2. Multiple low-amplitude regions in the peripheral zone of the prostate (Fig. 3). The prostatic capsule was ill defined. 3. Curvitinear, tubular echo-free regions immediately adjacent to the prostate extending from its anterior aspect around its lateral margins (Fig. 4). A periurethral low-amplitude or echo-free halo was present in all 40 patients (100%) in this study; peripheral zone low-amplitude regions were noted in 32 patients (80%), whereas tubular echo-free areas adjacent to the capsule were present in eight patients (20%). 2. Volumetric Studies
There appeared to be no overall change in the prostatic volume in association with treatment for prostatic inflammation because the mean percentage volume change measured in 36 patients was only 5%. However, when the patients were separated into two groups dependent on their clinical response to treatment, it became evident that there was a difference in
344
CLINICAL R A D I O L O G Y
Fig. 1 - Per-rectal ultrasonic scan of a normal prostate which has a crescent shape. The capsule is intact, appearing as a continuous line (arrows) and the internal echoes are, in gcneral, homogeneous. The ultrasonic transducer is seen posteriorly in the rectum.
Fig. 2-Per-rectal ultrasonic scan demonstrating the periurethral glandular and stromal tissue as a low-amplitude halo around a central echogenic area (arrows).
p r o s t a t i c m e a s u r e m e n t s . T h o s e p a t i e n t s (26) c o n s i d e r e d on clinical g r o u n d s to h a v e i m p r o v e d in r e s p o n s e to antibiotic treatment showed a mean percentage volume reduction of t h e p r o s t a t e of 16% ( r a n g e 7 - 3 5 % ) , w h e r e a s those with no e v i d e n c e of a clinical r e s p o n s e (14) h a d a m e a n v o l u m e increase of 13% ( r a n g e
3-35%).
DISCUSSION It is often difficult to d i f f e r e n t i a t e b a c t e r i a l a n d
Fig. 3-Per-rectal ultrasonography showing a heterogeneous echo pattern in the gland parenchyma due to multiple low-amplitude areas (arrows). The prostatic capsule is ill-defined.
Fig. 4 - Per-rectal ultrasonic scan demonstrating curvilinear, echo-free tubular areas adjacent to the prostate and extending from the anterior region of the gland around its lateral margins (arrows). There are also low-amplitude regions seen in the posterior part of the peripheral zone and surrounding the urethra, which is now lying near the centre of the gland.
n o n - b a c t e r i a l p r o s t a t i t i s f r o m a small, c o n f i n e d prostatic c a n c e r on digital e x a m i n a t i o n a l o n e (Jewitt, 1956). Until r e c e n t l y , it was c o n s i d e r e d difficult to d i f f e r e n t i a t e by p e r - r e c t a l u l t r a s o u n d b e t w e e n p r o s t a t i c calculi, bacterial a n d n o n - b a c t e r i a l p r o s t a t i t i s and c o n f i n e d p r o s t a t i c carcinoma. Recent experience indicates that prostatic calculi h a v e an easily i d e n t i f i a b l e a p p e a r a n c e on u l t r a s o u n d ( H a r a d a et al., 1979; P e e l i n g a n d Griffiths, 1984), but it is still difficult to d i f f e r e n t i a t e ultrasonically b e t w e e n i n f l a m m a t o r y d i s e a s e of t h e p r o s t a t e and p r o s t a t i c c a n c e r b e c a u s e b o t h c o n d i t i o n s can c r e a t e similar u l t r a s o n i c a p p e a r a n c e s ( H a r a d a et al., 1979;
ULTRASOUND IN PROSTATIC INFLAMMATION
Resnick, 1980). Therefore, any additional ultrasonic features which can support a diagnosis of inflammatory prostatic disease would be a welcome development to differentiate between benign and malignant disease and should increase the probability of accurate diagnosis made on the basis of the ultrasonic features. The exact morphology of the three ultrasonic features is uncertain. The commonest feature in patients with prostatitis was the demonstration of the periurethral glandular and stromal tissue as a low-amplitude halo around a central echogenic area. We have seen this appearance in all proven cases of bacterial and non-bacterial prostatitis and we believe this might be a valid sign of prostatitis. However, others (Harada et al., 1980) only noted this appearance in 50% of their cases of prostatitis and also commented that it was visualised in 69% of normals. The specificity of this sign should, therefore, remain under review for the present. The next most frequent ultrasonic feature in these patients was a heterogeneous echo pattern with multiple areas of low-amplitude echoes in the gland parenchyma. Occasionally, these coalesce to involve larger areas of the gland. These appearances might represent multiple focal areas of prostatic infection. When present, the prostatic capsule was usually ill-defined. The least common pattern was the appearance of curvilinear echo-free tubular areas adjacent to the prostate, extending from the anterior regions of the gland around its lateral margins. It is possible that these appearances were due to engorged and prominent veins in the prostatic venous plexus secondary to prostatic inflammation. Although the prostatic venous plexus may often be demonstrated during per-rectal ultrasonography, we only saw prostatic veins with this degree of prominence in patients with prostatic inflammation. It is of considerable interest that there was evidence of reduction of volume of the prostate in patients who had experienced a satisfactory response to treatment and it might be significant that not one patient in this group showed an increase of volume. This contrasts with the observations that the volume and weight remained unchanged or increased if there had been no improvement in symptoms following treatment. It has been shown (Carpentier et al., 1982; Peeling, 1983) that, in the treatment of prostatic cancer, volume reduction mirrors response to endocrine treatment and, therefore, can be used to monitor response to treatment. Hence, it is possible that a change in volume and weight of the prostate might also be an indicator of treatment
32
345
response in patients with prostatitis, although ultrasonically there was little change in the other features of prostatitis in our patients following a mean interval of observation of 12 weeks. Acknowledgements. The authors gratefully acknowledge the assistance of the Department of Medical Illustration, Royal Gwent Hospital, Newport in preparing the figures and Miss Janet Owen for typing the manuscript.
REFERENCES Blacklock, N. J. (1981). Prostatis - pathogenesis, clinical features and management. In RecentAdvaces in Urology/Andrology, No. 3, pp. 185-197. Churchill Livingstone, Edinburgh. Braeckman, J. & Denis, L. (1983). The practice and pitfalls of ultrasonography in the lower urinary tract. European Urology, 9, 193-201. Brooman, P. J. C., Peeling, W. B., Griffiths, G. J., Roberts, E. E. & Evans, K. T. (1981a). A comparison between digital examination and per-rectal ultrasound in the evaluation of the prostate. British Journal of Urology, 53, 617-620. Brooman, P. J. C., Griffiths, G. J., Roberts, E. E., Peeling, W. B. & Evans, K. T. (1981b). Per-rectal ultrasound in the investigation of prostatic disease. Clinical Radiology, 32, 669-676. Carpentier, P. J., Schroder, F. H. & Blom, J. H. M. (1982). Transrectal ultrasonography in the follow-up of prostatic carcinoma patients. Journal of Urology, 128, 742-746. Gammelgaard, J. & Holm, H. H. (1980). Transurethral and transrectal ultrasonic scanning in urology. Journal of Urology, 124, 863-868. Harada, K., Igani, D. & Tamahashi, Y. (1979). Gray scale transrectal ultrasonography of the prostate. Journal of Clinical Ultrasound, 7, 45-49. Harada, K., Tamahashi, Y., Igani, D., Numata, I. & Orikasa, S. (1980). Clinical evaluation of inside echo patterns in gray scale prostatic echography. Journal of Urology, 124, 216-220. Jewitt, H. J. (1956). Significance of the palpable prostatic nodule. Journal of the American Medical Association, 160, 838-839. Peeling, W. B. (1983). Castration for prostatic carcinoma still an alternative form of treatment? In Androgens and Anti-androgens, ed. Schroder, F. H., pp. 127-128. Weess, Schering Nederland. Peeling, W. B., Griffiths, G. J., Evans, K. T. & Roberts, E. E. (1979). Diagnosis and staging of prostatic cancer by transrectal ultrasonography. A preliminary report. British Journal of Urology, 51, 565-569. Peeling, W. B. & Griffiths, G. J. (1984). Clinical staging of prostatic cancer. In Urology, Vol. 2, The Prostate, Butterworths International Medical Reviews. Butterworths, London (in press). Resnick, M. (1980). Ultrasound evaluation of the prostate and bladder. Seminars in Ultrasound, 1, 69-79. Stamey, T. A. (1980). Pathogenesis and Treatment of Urinary Tract Infections, pp. 1-51. Williams and Wilkins, Baltimore. Watanabe, H., Date, S., Ohe, H., Saitch, M. & Tanaka, S. (1980). A survey of 3000 examinations by transrectal ultrasonotomography. The Prostate, 1,271-278.