Biomedical subjects

Leo Pallwein

Publications and source records attributed to Leo Pallwein.

15 recordsLinked to original sources

PubMed2007

Value of contrast-enhanced ultrasound and elastography in imaging of prostate cancer.

PURPOSE OF REVIEW: Prostate cancer is the most commonly diagnosed malignancy in men. Gray-scale ultrasound-guided systematic biopsy is the standard of care for prostate cancer detection in men with an elevated prostate-specific antigen or an abnormal digital rectal examination. Systematic biopsy may miss up to 35% of clinically relevant cancers. Color and power Doppler ultrasound, ultrasound contrast agents, and elastography have and will dramatically change the role of ultrasound in prostate cancer diagnosis. RECENT FINDINGS: Several reports have demonstrated that contrast-enhanced ultrasound investigations of the blood flow of the prostate allow for prostate cancer visualization and therefore, for targeted biopsies. Comparisons between systematic and contrast-enhanced ultrasound-targeted biopsies have shown that the targeted approach detects more cancers with a lower number of biopsy cores. Furthermore, contrast-enhanced ultrasound has been shown to detect cancers with higher Gleason scores compared with the systematic approach, which seems to improve prostate cancer grading. In addition, elastography is a new ultrasound technique that allows for the assessment of tissue elasticity. SUMMARY: Contrast-enhanced ultrasound and elastography improve prostate cancer detection and may be useful for prostate cancer grading and staging. Future clinical trials will be needed to determine the promise of these new advances for ultrasound of the prostate evolving into clinical applications.

Humans↗

PubMed2007

Value of 3-dimensional transrectal/transvaginal sonography in diagnosis of distal ureteral calculi.

OBJECTIVE: In a prospective study, the feasibility of 3-dimensional (3D) transrectal/transvaginal sonography in comparison with transabdominal sonography and intravenous urography (IVU) in identifying distal ureteral calculi was evaluated. METHODS: Sixty-two patients in the urologic clinic with clinical suspicion of distal ureteral calculi were included. The patients consisted of 44 men and 18 women with a mean age +/- SD of 44 +/- 17 years. These patients underwent 3D transrectal/transvaginal sonography, transabdominal sonography with IVU, and, finally, ureterorenoscopy. RESULTS: Fifty-nine patients were confirmed to have distal ureteral calculi on the basis of urologic intervention (ureterorenoscopy). Three patients had a spontaneous stone passage immediately after imaging completion. The median size of the calculi was 3.7 +/- 2.00 mm. Transabdominal sonography detected 34 of the 62 patients with calculi (sensitivity, 55%). The median size of the calculi was calculated as 5.0 +/- 2.4 mm. The examination time was 6.5 +/- 2.7 minutes. Intravenous urography detected 44 of the 62 patients with ureterolithiasis (sensitivity, 71%). Herein, the median stone size was measured as 3.9 +/- 1.9 mm, and the examination time was 38 +/- 17 minutes. The combination of transabdominal sonography and IVU in visualization of ureterolithiasis raised the sensitivity to 81% (50 of 62 patients). Three-dimensional transrectal/transvaginal sonography showed ureterolithiasis in all 62 patients confirmed to have distal ureteral calculi (sensitivity and specificity, 100%). The median size of the calculi was calculated as 4.4 +/- 2.2 mm, and the examination took 1.9 +/- 0.6 minutes. CONCLUSIONS: The data in our prospective study show that transrectal/transvaginal sonography with 3D image assessment is superior to IVU and abdominal sonography for diagnosing distal ureteral calculi.

Adult↗

PubMed2006

Three-dimensional ultrasonography of the urinary bladder: preliminary experience of assessment in patients with haematuria.

OBJECTIVE: To assess the value of three-dimensional (3D) vs two-dimensional (2D) ultrasonography (US) in the diagnostic evaluation of the urinary bladder in patients with haematuria. PATIENTS AND METHODS: In all, 42 patients with painless haematuria and/or irritative voiding symptoms were examined with 2D- and 3D-US. US was done with an Acuson Sequoia unit (Siemens Medical Sol. Mountain View, CA, USA) and the Perspective(R) 3D technique, to assess the presence of bladder lesions, including bladder cancer, bladder wall hypertrophy with trabeculation and diverticula, mucosal bladder folds or re-growth of the prostate mimicking a bladder tumour. The imaging findings were compared with cystoscopy and/or bladder biopsy. RESULTS: In 21 of the 42 patients (50%) cystoscopy with bladder biopsy revealed bladder cancer. Overall, 3D-US gave a correct diagnosis for 36 of 42 patients (86%). All 21 bladder cancers were correctly diagnosed, and 15 (71%) of the 21 benign bladder lesions were correctly identified. By contrast, 2D-US findings gave suspected bladder cancer in all patients. CONCLUSIONS: 3D-US is significantly more accurate than standard 2D-US in the diagnostic evaluation of patients with haematuria. Thus, this diagnostic technique might be useful for routine evaluation of the urinary bladder.

Aged↗

PubMed2006

Management of incidental impalpable intratesticular masses of < or = 5 mm in diameter.

OBJECTIVE: To gain more insight into the histology of small incidental intratesticular lesions and evaluate the need for surgical management, as exploratory surgery is the only way to exclude malignancy in testicular tumours. PATIENTS AND METHODS: Between September 2000 and April 2005, incidental intratesticular masses of < or = 5 mm in diameter were found in 20 men undergoing scrotal ultrasonography for reasons other than suspected testicular tumour. After staging, an organ-sparing approach including frozen-section analysis was used to obtain histological data. RESULTS: The mean diameter of the detected tumour masses was 3.5 mm, and the mean (range) age of the patients was 36.4 (26-58) years. Four men (20%) had orchidectomy because the tumours were found to be malignant; the resected specimens yielded multifocal testicular intraepithelial neoplasia (TIN) in all patients and additional seminomatous tumour cells elsewhere in the testis in one. Frozen-section results were false-negative in one patient and he had orchidectomy after having established the definitive histological diagnosis. The 16 patients with benign lesions were correctly diagnosed and their testicles were not removed. CONCLUSIONS: Advanced and innovative ultrasonography technology allows the detection of increasingly small testicular masses. In the present series, most incidental intratesticular lesions were benign. In patients with malignant lesions, multifocal TIN and/or distant seminomatous foci were present despite the tumour being small. Therefore, it is essential to perform exploratory surgery as it is the only way to obtain accurate histological findings, thus providing oncological efficacy and precluding removal of a testicle bearing a benign lesion.

Adult↗

PubMed2006

The use of three-dimensional computed tomography for assessing patients before laparoscopic adrenal-sparing surgery.

OBJECTIVE: To evaluate the efficacy of three-dimensional computed tomography (3D-CT) in delineating the relationship of the adrenal mass to adjacent normal structures in preparation for laparoscopic partial adrenalectomy. PATIENTS AND METHODS: Multislice CT (1 mm slices, 0.5 s rotation time) was used to evaluate 12 patients before adrenal-sparing surgery for aldosterone-producing adenoma or phaeochromocytoma. The CT data were reconstructed using two rendering techniques; (i) volume rendering with the modified VOLREN software (Johns Hopkins Hospital, Baltimore, MD, USA) which allowed interactive 3D examination of the whole data volume within a few minutes; (ii) surface representations only of the interesting structures (kidney, adrenal tumour, vessels) represented in different colours and depicted together in a 3D scene using the software package 3DVIEWNIX. RESULTS: In all, 14 adrenal masses in 12 patients were evaluated with 3D-CT; the number and location of lesions was accurate in all cases with both rendering techniques. The coloured surface-rendered images showed a consistently better delineation of the adrenal tumour from the normal tissue than did the volume-rendering technique. From this information all laparoscopic partial adrenalectomies could be completed as planned. CONCLUSIONS: Interactive visualization of volume-rendered CT images was helpful for the planning and successful performance of the procedure, but coloured surface-rendered CT provided more convenient, immediate and accurate intraoperative information.

Adenoma↗

PubMed2006

Atherosclerosis as a risk factor for benign prostatic hyperplasia.

OBJECTIVES: To evaluate the relationship between clinical benign prostatic hyperplasia (BPH) and atherosclerosis, using colour Doppler ultrasonography (CDUS) and symptom scores. PATIENTS, SUBJECTS AND METHODS: CDUS was used to evaluate prostatic vascularity in four groups of men, comprising young healthy subjects, patients presenting with coronary artery disease (CAD), diabetes mellitus, or peripheral arterial occlusive disease (PAOD). Resistive index (RI) measurements and computer-assisted quantification of colour pixel density (CPD) were used to objectively evaluate perfusion. The International Prostate Symptom Score (IPSS) and the International Index of Erectile Function were used to quantify symptoms. RESULTS: In diabetic patients and men with PAOD, perfusion of the transition zone (TZ) of the prostate was significantly lower (P < 0.001) and the RI of the TZ was significantly higher (P < 0.001) than in healthy controls and men with CAD. In diabetics and men with PAOD, the mean prostate volume was greater than in healthy controls and men with CAD. The IPSS in patients with vascular damage (diabetes, PAOD) was significantly worse than in the control group. CONCLUSIONS: The significantly lower CPD and higher RI values of the TZ in patients with vascular disease than in healthy subjects support the hypothesis that an age-related impairment of blood supply to the prostate has a key role in the development of BPH.

Aged↗

PubMed2006

Dynamic transurethral sonography and 3-dimensional reconstruction of the rhabdosphincter and urethra: initial experience in continent and incontinent women.

OBJECTIVE: The purpose of this study was to evaluate the female urethra and the striated urinary sphincter, the rhabdosphincter (RS), by means of dynamic transurethral sonography and sonographic 3-dimensional (3D) reconstructions. METHODS: In 15 female patients with urinary stress incontinence (mean age, 67.5 years) and 5 continent women (mean age, 48.3 years), morphologic characteristics and function of the RS and urethra were examined with a 10-MHz transurethral ultrasound transducer. With the help of a mechanical pullback system, the transducer was slowly retracted to scan the whole urethra and the RS from the bladder neck to the urethral orifice. Subsequently, 3D reconstructions of the urethra using an integrated computer system were performed. The RS as well as the length of the urethra were investigated under contracted and noncontracted conditions to measure contractility of the RS and dynamic changes of the lower urinary tract. RESULTS: Partial or complete loss of RS function was detected in patients with stress incontinence. The findings on sonography were found to correlate well with the grade of incontinence. Furthermore, under contraction of the RS, a median increase in urethral length was observed. In incontinent patients, the increase in the urethral length was statistically significantly less (P = .04), which was related to the reduced contractility of the RS. CONCLUSIONS: Dynamic transurethral sonography with subsequent 3D reconstructions allows for assessment of function and morphologic characteristics of the RS and urethra. Normal contraction of the RS results in an elongation of the urethra.

Adolescent↗

PubMed2005

Prostate ultrasound--for urologists only?

The value of ultrasound (US) in the diagnosis of prostate cancer has dramatically increased in the past decade. This is mainly related to the increasing incidence of prostate cancer, the most common cancer in men and one of the most important causes of death from cancer in men. The value of conventional gray-scale US for prostate cancer detection has been extensively investigated, and has shown a low sensitivity and specificity. Therefore conventional gray-scale US is mainly used by urologists for guiding systematic prostate biopsies. With the development of new US techniques, such as color and power Doppler US, and the introduction of US contrast agents, the role of US for prostate cancer detection has dramatically changed. Advances in US techniques were introduced to further increase the value of US contrast agents. Although most of these developments in US techniques, which use the interaction of the contrast agent with the transmitted US waves, are very sensitive for the detection of microbubbles, they are mostly unexplored, in particular for prostate applications. Early reports of contrast-enhanced US investigations of blood flow of the prostate have shown that contrast-enhanced US adds important information to the conventional gray-scale US technique. Furthermore, elastography or 'strain imaging' seems to have great potential in prostate cancer detection. Since these new advances in US are very sophisticated and need a long learning curve, radiologists, who are overall better trained with these new US techniques, will play a more important role in prostate cancer diagnosis. Current trends show that these new US techniques may allow for targeted biopsies and therefore replace the current 'gold standard' for prostate cancer detection--the systematic biopsy. Consequently the use of these new US techniques for the detection and clinical staging of prostate cancer is promising. However, future clinical trials will be needed to determine if the promise of these new US advances of the prostate evolves into clinical application.

Humans↗

PubMed2005

Prostate cancer detection in men with prostate specific antigen 4 to 10 ng/ml using a combined approach of contrast enhanced color Doppler targeted and systematic biopsy.

PURPOSE: Transrectal gray scale ultrasound guided biopsy is the standard method for diagnosing prostate cancer (PC). Improved cancer detection with ultrasound contrast agents is related to better detection of tumor vascularity. We evaluated the impact of a combined approach of contrast enhanced, color Doppler targeted biopsy (CECD) and systematic biopsy (SB) for the PC detection rate in men with prostate specific antigen (PSA) 4.0 to 10 ng/ml. MATERIALS AND METHODS: We examined 380 screening volunteers with a total PSA of 4.0 to 10 ng/ml (percent free PSA less than 18). CECD was always performed before SB. Another investigator blinded to contrast enhanced findings performed 10 SBs. The cancer detection rate for the CECD, SB and combined approaches was assessed. RESULTS: PC was detected in 143 of 380 patients (37.6%, mean total PSA 6.2 ng/ml). The PC detection rate for CECD and for SB was 27.4% and 27.6%, respectively. The overall cancer detection rate with the 2 methods combined was 37.6%. For targeted biopsy cores the detection rate was significantly better than for SB cores (32.6% vs 17.9%, p <0.01). CECD in a patient with cancer was 3.1-fold more likely to detect PC than SB. CONCLUSIONS: CECD allows for the detection of lesions that cannot be found on gray scale ultrasound or SB. CECD allows for assessment of neovascularity associated with PC. However, the combined use of CECD and SB allows for maximal detection of PC with a detection rate of 37.6% in our patients with PSA 4 to 10 ng/ml.

Adult↗

PubMed2004

Power Doppler ultrasound imaging for quantification of urinary bladder neck blood flow changes.

This study was designed to evaluate power Doppler imaging for assessment of urinary bladder neck blood flow in comparison with laser Doppler flowmetry (LDF) in an animal model. Transrectal power Doppler ultrasound (US) and LDF of the urinary bladder neck were performed in three anesthetized pigs during comparative cystometry. Normal saline (NaCl) was used for the first run, followed by a second run with 0.2 mol/L potassium chloride (KCl). Standardized sonographic equipment settings (Acuson Sequoia 512); MountainView, CA) were used for power Doppler imaging. Computer-assisted calculation of color pixel density (CPD) of power Doppler images was performed using Scion Image) software image analysis. Tissue perfusion units (TPU) were measured using a BLF21 laser Doppler flowmeter (Transonic Systems Inc., Ithaca, NY, USA). The power Doppler results were compared with the findings obtained by LDF. NaCl filling resulted in a mean CPD increase at the bladder neck from 18.65 (+/- 1.78) at empty bladder to 37.8 (+/- 1.84) at 100 mL and to 88.32 (+/- 1.35) at full bladder capacity (C(max)) of 270 mL, respectively. With KCl filling, a mean CPD increase from 18.65 (+/- 1.78) to 59.63 (+/- 0.5) at 100 mL and 110.82 (+/- 2.98) at full bladder capacity (270 mL) was observed. The CPD increase was significantly higher for KCl than with NaCl (p < 0.001). With NaCl filling, bladder neck blood flow increased from 22 TPU (empty) to 46 TPU (100 mL) and 62.5 TPU at C(max), compared to 22 TPU, 50 TPU and 102.5 TPU with KCl. CPD and TPU measurements showed a strong correlation at p = 0.01. In conclusion, transrectal power Doppler US image quantification is a feasible and accurate method for assessing blood flow changes in the urinary bladder neck.

Animals↗

PubMed2004

The influence of left renal vein entrapment on outcome after surgical varicocele repair: a color Doppler sonographic demonstration.

OBJECTIVE: To evaluate the impact of left renal vein entrapment on outcome after surgical varicocele repair using color Doppler sonography. METHODS: Eighty-four men had varicoceles on color Doppler sonography (2 right sided, 74 left sided, and 8 bilateral), which were diagnosed on the basis of a venous diameter of 3 mm or greater and venous retrograde flow in the pampiniform plexus of veins during the Valsalva maneuver or when changing from a supine to an upright position. Diagnosis of the left renal vein entrapment was based on the following criteria: antero-posterior diameter of greater than 1 cm and peak velocity of less than 15 cm/s for the left renal vein at the mid portion and anteroposterior diameter of less than 0.2 cm and peak velocity of greater than 110 cm/s (or, alternatively, a diameter ratio and peak velocity ratio of >5) for the left renal vein between the aorta and superior mesenteric artery. All patients underwent surgical varicocele repair. In postoperative follow-up, we compared the presence of left renal vein entrapment with the frequency of varicocele recurrence. RESULTS: Sixteen (19%) of 84 patients had left renal vein entrapment with a left-sided varicocele. Postoperatively (mean follow-up +/- SD, 19.3 +/- 11.7 months), 27 (32.2%) of 84 had varicocele recurrence, including all 16 patients with left renal vein entrapment and 11 (20.1%) of 68 patients without left renal vein entrapment. The varicocele recurrence rate was significantly greater in patients with left renal vein entrapment (P < .001, Fisher exact test). CONCLUSIONS: The presence of left renal vein entrapment resulted in a significantly higher varicocele recurrence rate. Patients with varicoceles should routinely be evaluated for the presence of left renal vein entrapment before surgical repair.

Adult↗

PubMed2002

The value of contrast-enhanced color Doppler ultrasound in the detection of vascularization of finger joints in patients with rheumatoid arthritis.

OBJECTIVE: A prospective study was performed to assess the usefulness of contrast-enhanced color Doppler ultrasound (CDUS) in the evaluation of intraarticular vascularization of finger joints in patients with rheumatoid arthritis (RA). METHODS: We investigated 198 finger joints in 46 patients with RA, and 80 finger joints in 10 healthy volunteers. Joints with varying levels of clinical activity of inflammation were classified as being active, moderately active, or inactive. CDUS was performed with a high-frequency multi-D linear array transducer. A microbubble-based ultrasound (US) contrast agent (Levovist; Schering, Berlin, Germany) was intravenously infused. Doppler findings were rated on the basis of both unenhanced and contrast-enhanced CDUS images. RESULTS: Healthy joints showed no intraarticular vascularization on either unenhanced or contrast-enhanced CDUS. Unenhanced CDUS detected intraarticular vascularization in 7 (8%) of 83 inactive joints, in 31 (52%) of 60 moderately active joints, and in 32 (58%) of 55 active joints. Contrast-enhanced CDUS detected intraarticular vascularization in 41 (49%) of 83 joints with inactive RA, in 59 (98%) of 60 joints with moderately active RA, and in all 55 joints with active RA. Detection of intraarticular vascularization was improved by administration of the microbubble-based US contrast agent (P < 0.001). Contrast-enhanced CDUS demonstrated differences in intraarticular vascularization between joints with inactive RA and those with active RA (P < 0.001), between joints with inactive RA and those with moderately active RA (P < 0.001), and between joints with moderately active RA and those with active RA (P < 0.001). CONCLUSION: The use of a microbubble-based US contrast agent significantly improved the detection of intraarticular vascularization in the finger joints of patients with RA. This technique seems to be a useful adjunct in the assessment of disease activity.

Adult↗

PubMed2002

Laparoscopic pyeloplasty for UPJ obstruction with crossing vessels: contrast-enhanced color Doppler findings and long-term outcome.

OBJECTIVES: To evaluate, in the present long-term follow-up study, contrast-enhanced color Doppler imaging (CDI) findings and the clinical outcome of patients with crossing vessels at the obstructed ureteropelvic junction (UPJ), who underwent laparoscopic pyeloplasty. In a previous study, contrast-enhanced CDI proved capable of detecting crossing vessels at the UPJ. METHODS: A total of 23 patients, who had undergone laparoscopic pyeloplasty and displacement of crossing vessels for UPJ obstruction at least 2 years before this study (mean 27 months), underwent contrast-enhanced CDI, intravenous urography, and renography. Contrast-enhanced CDI was performed using intravenously administered Levovist to assess the displacement of the vessels relative to the UPJ. All patients completed analog follow-up pain scales and quality-of-life assessment questionnaires. RESULTS. Contrast-enhanced CDI revealed a cranial displacement (mean 1.3 cm) of the crossing vessels from the UPJ in all 23 cases. Intravenous urography showed a decrease in the degree of hydronephrosis, with a success rate of 100% in low-grade and 86% in high-grade hydronephrosis. The split renal function improved from 39.7% to 48.1%. Analog pain scale measurements demonstrated a mean improvement in pain of 92% (range 73% to 100%) and a mean quality-of-life score of 94 (range 78 to 100). CONCLUSIONS: Our series of patients with crossing vessels at the UPJ treated by laparoscopic pyeloplasty showed an excellent long-term successful outcome. Contrast-enhanced CDI allows for preoperative detection, as well as postoperative assessment, of the displacement of the crossing vessel. We recommend that the presence of a crossing vessel be routinely determined preoperatively, because it may influence the choice of treatment modality and thereby the clinical outcome.

Adolescent↗

PubMed2002

Contrast enhanced reflux sonography in children: a comparison to standard radiological imaging.

PURPOSE: The diagnosis of vesicoureteral reflux is routinely performed by voiding cystourethrography. Especially in the course of conservative treatment, the radiation dose might increase during the years. With the development of ultrasound echo enhancing agents we assessed their diagnostic efficacy for evaluation of vesicoureteral reflux to replace voiding cystourethrography with radiation-free ultrasound. MATERIALS AND METHODS: A total of 104 children with a mean age of 5.4 years were examined using echo enhancing ultrasound after informed consent was obtained. For control purposes, all children underwent standard voiding cystourethrography as well. The diagnosis of vesicoureteral reflux was positive when microbubbles appeared in the ureter or renal pelvis. The sonographic findings were correlated with those obtained by standard voiding cystourethrography. RESULTS: Of the 208 ureter and renal units investigated vesicoureteral reflux was detected in 76 (37%) by both technologies. Diagnosis was made sonographically in 5 units and by voiding cystourethrography in 3. All reflux grades (I to V) could be identified. The specificity and sensitivity of the contrast reflux ultrasound were significantly high. The long contrast time of up to 30 minutes combined with the high contrast effect resulted in convincing images with high levels of diagnostic confidence. CONCLUSIONS: Our results clearly demonstrate that the diagnostic accuracy of vesicoureteral reflux by contrast enhanced ultrasound is statistically significant compared to standard radiological voiding cystourethrography. Therefore, this methodology represents an exceptional approach to reduce the number of children being exposed to ionizing radiation especially during conservative followup.

Adolescent↗

PubMed2002

Comparison of contrast enhanced color Doppler targeted biopsy with conventional systematic biopsy: impact on prostate cancer detection.

PURPOSE: We performed a prospective study to determine whether a limited biopsy approach with contrast enhanced color Doppler ultrasound targeted biopsy of the prostate would detect cancer as well as gray scale US guided systematic biopsy with a larger number of biopsy cores. MATERIALS AND METHODS: We examined 230 male screening volunteers with a total prostate specific antigen of 1.25 ng./ml. or greater and free-to-total prostate specific antigen less than 18%. Two independent examiners evaluated each subject and a single investigator performed 5 or fewer contrast enhanced targeted biopsies into hypervascular regions in the peripheral zone during intravenous infusion of the US contrast agent Levovist (Schering, Berlin, Germany). Subsequently another examiner performed 10 systematic prostate biopsies. The cancer detection rates of the 2 techniques were compared. RESULTS: Cancer was detected in 69 of the 230 patients (30%), including 56 (24.4%) by contrast enhanced targeted biopsy and in 52 (22.6%) by systematic biopsy. Cancer was detected by targeted biopsy alone in 17 patients (7.4%) and by systematic biopsy alone in 13 (5.6%). The overall cancer detection rate by patient was not significantly different for targeted and systematic biopsy (p = 0.58). The detection rate for targeted biopsy cores (10.4% or 118 of 1,139 cores) was significantly better than for systematic biopsy cores (5.3% or 123 of 2,300 cores, p <0.001). Contrast enhanced targeted biopsy in a patient with cancer was 2.6-fold more likely to detect prostate cancer than systematic US guided biopsy. CONCLUSIONS: Contrast enhanced color Doppler targeted biopsy detected as many cancers as systematic biopsy with fewer than half the number of biopsy cores. Although an increase in cancer detection was achieved by combining targeted and systematic techniques in this screening population, contrast enhanced targeted biopsy alone is a reasonable approach for decreasing the number of biopsy cores.

Adult↗