Peter L. Cooperberg

Real-time spatial compound imaging: Application to breast, vascular, and musculoskeletal ultrasound

Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image quality compared with conventional ultrasound, primarily because of reduction of speckle, clutter, and other acoustic artifacts. Early clinical experience suggests that real-time spatial compound imaging can provide improved contrast resolution and tissue differentiation that is beneficial for imaging the breast, peripheral blood vessels, and musculoskeletal injuries. Future development of real-time spatial compound imaging will help address the bulk of general imaging applications by extending this technology to curved array transducers, tissue harmonics, panoramic imaging, and three-dimensional sonography.

Magnetic resonance imaging of scrotal diseases: when it makes the difference

OBJECTIVES To investigate the utility of magnetic resonance imaging (MRI) after inconclusive sonography in the evaluation of scrotal disease. METHODS From 1993 to 1999, 622 patients underwent ultrasonography (US) with state-of-the-art equipment to evaluate scrotal diseases. Twenty-six patients, two with bilateral and distinct diseases (age range 1--63 years, mean 33), had an inconclusive sonogram and were sent for MRI. The MRI results were compared with previous US reports and with the final diagnosis. RESULTS MRI yielded additional and correct information (compared with US), coincident with the final diagnosis in 23 cases (82.1%). In regard to lesions suspected of malignancy at US (17 cases), MRI had a great concordance with the final diagnosis and was statistically significant (P <0.002, kappa test). CONCLUSIONS The results of our study indicate that MRI could help elucidate scrotal dilemmas found at US, although the small percentage of inconclusive sonograms confirms this technique as the first choice when imaging is required in scrotal diseases.

Color flow duplex screening of infrainguinal grafts combining low- and high-velocity criteria.

The aim of this prospective study was to evaluate the ability of duplex ultrasonography to identify infrainguinal grafts at high risk for failure. The criteria used identified low flow by low peak systolic velocity (less than 45 cm/s) and stenosis by high velocity (greater than 300 cm/s) or by velocity at the stenosis three times the velocity in the adjacent normal graft. A total of 114 patent grafts were scanned and compared with concurrent angiograms. Duplex scanning correctly identified 18 high-risk grafts by low-flow criteria and an additional 21 by stenosis criteria. There was one false-negative finding (sensitivity 98 percent). The velocity ratio of the stenosis to the adjacent graft was useful in estimating the degree of stenosis. Color flow duplex imaging reduced examination time through visual feedback by highlighting the graft and areas of high velocity. These results indicate that color flow duplex scanning, combining low- and high-peak systolic criteria, is a very sensitive screening test in the early detection of failing grafts.

Sonographic visualization of the ureter in pregnancy

We describe a method of differentiating physiological from pathological dilatation of the renal collecting system in pregnant patients. In physiological hydronephrosis the dilated ureter extends down only to the level of the common iliac artery. In 2 patients with distal ureteral stones a dilated ureter was visualized past the vessels. To determine the frequency and reliability of visualizing the ureters in pregnant patients 105 consecutive asymptomatic pregnant patients were examined. Hydronephrosis was found in 83 kidneys in 59 of the patients. The dilated ureter was visualized in 64 of the renal units. The anatomy was well demonstrated by color flow Doppler scanning and in all of these cases the dilated ureter was seen to taper where it crossed the common iliac artery. These results suggest that the presence of a dilated ureter past the iliac artery is strong evidence for pathological distal ureteral obstruction in pregnancy.

Computer-aided detection of pulmonary embolism on CT angiography: Initial experience

Objective To evaluate the performance of a computer-aided detection (CAD) system for diagnosis of pulmonary embolism on computed tomography (CT) pulmonary angiography. Materials and Methods One hundred and four pulmonary CT angiograms for pulmonary emboli (PE) were reviewed both by radiologists and a CAD detection system (ImageChecker CT V2.0, R2 Technology Inc, Sunnyvale, CA). CT scans, read and reported by radiologists in a routine daily clinical setting, were later processed by the CAD system. The performance of the CAD system was analyzed. Results Forty-five PE were identified by the radiologists in 15 patients. The CAD system revealed 123 findings, interpreted by the system as PE. Twenty-six of them, detected in 8 patients, represented true-positive results. Ninety-seven (78.9%) CAD findings were not true PE and were defined as false-positive. Nineteen true PE in 7 patients were missed by the CAD system constituting 42% false-negative rate. Sensitivity of the CAD system was 53.3% and the specificity was 77.5%. The positive predictive value of CAD system was 28.5% and the negative predictive value was 90.7%. Conclusions With the evaluated CAD system, it is relatively simple and fast to check all detected findings and decide if they represent true PE. However, high false-negative results demand technologic improvement, to increase the sensitivity of the system. It is anticipated to become a promising supplement to the work and eyes of the radiologist in detecting PE on pulmonary CT angiography.

Sonographic characteristics of the urethrovesical anastomosis in the early post-radical prostatectomy patient

It is possible that the advent of more aggressive surgical approaches to carcinoma of the prostate, including neoadjuvant and adjuvant therapy, will lead to a higher incidence of pelvic recurrence rates in coming years. A method of sequentially monitoring the region of the urethrovesical anastomosis for early recurrence that is more accurate than digital rectal examination is required. Transrectal ultrasound is an established technique for the preoperative assessment of prostate cancer. It has also been used postoperatively to guide a biopsy needle into palpably suspicious areas at the urethrovesical junction or for random biopsies in patients with elevated prostate specific antigen levels. However, the sonographic anatomy of the postoperative urethrovesical junction has not previously been described. In this prospective study we analyze the transrectal sonographic characteristics of the neoanatomy in 30 patients, all within 3 months following surgery for clinically intracapsular disease. We describe features of the neoanatomy, such as anterior tissue nodules and anastomotic rings. Because of distinct variations in the neoanatomy of different patients we recommend early postoperative transrectal biplanar sonography to establish a baseline image for each individual case. This would be useful for later comparison and may prevent a false positive scan on subsequent followup studies.

Early Hydronephrosis following Aortic Bifurcation Graft Surgery: A Prospective Study

The true incidence and natural history of ureteral obstruction following reconstructive vascular surgery have not been determined previously. A series of 101 patients undergoing aortofemoral and aortoiliac reconstructive surgery were studied prospectively to determine the frequency of hydronephrosis in the first postoperative year. Serial real-time ultrasound examinations were performed preoperatively as well as at 1 week, 3 months and 1 year postoperatively. Ninety-three patients completed the study, with a total of 181 kidneys at risk. Hydronephrosis of mild to moderate degree developed in 15 kidneys (8 per cent) in 11 patients (12 per cent). All patients were asymptomatic, and the obstruction resolved spontaneously in 10 of 11 patients, including 9 within 3 months of onset. Only a single case persisted at 1 year. This study confirms that the hydronephrosis that occurs within the first year after aortic bifurcation graft surgery is not uncommon but it is rarely of clinical significance in the asymptomatic patient.

Extended field-of-view ultrasound

When ultrasound became a clinical reality in the 1970s, extended field of view was the only form of imaging available because all ultrasound images were created with articulated arm scanners that encompassed the area of interest in its entirety. With the advent of high-quality real-time imaging in the 1980s, the extended field of view was lost, and with it went an important diagnostic component as well as an important means of communicating diagnostic findings to referring clinicians. Through the magic of computer technology, extended field of view imaging is back! Extended field of view images can now be created very easily and conveniently, in real time. The convenience and accuracy of real-time imaging is maintained while important anatomical perspectives are added. This article reviews the status of real-time extended field of view sonography. The technical details as well as the clinical relevance of this method are summarized. The day-to-day clinical utility of extended field of view imaging is liberally illustrated.

Chest Radiographic and CT Manifestations of Chronic Granulomatous Disease in Adults

OBJECTIVE The purpose of this study was to describe the thoracic radiologic findings of chronic granulomatous disease in adults. MATERIALS AND METHODS We retrospectively analyzed the chest radiographic and CT findings in four adults with chronic granulomatous disease during five episodes of lower respiratory tract infection. RESULTS Chest radiographic findings included areas of consolidation (60%), diffuse reticulonodular opacities (40%), pleural effusion (20%), and pulmonary artery enlargement (20%). CT findings included areas of consolidation (60%), pulmonary nodules in a random distribution (60%), centrilobular nodules (60%), tree-in-bud opacities (40%), areas of scarring and traction bronchiectasis (100%), emphysematous changes (75%), areas of decreased attenuation and vascularity associated with air trapping on expiratory CT (50%), mediastinal and/or hilar lymphadenopathy (60%), pulmonary artery enlargement (50%), and pleural effusion (20%). Areas of consolidation and nodules were the most prominent findings and at histologic examination were found to be associated with infection or granulomatous inflammation. CONCLUSION The pulmonary radiologic findings of chronic granulomatous disease include consolidation, nodules, areas of scarring, traction bronchiectasis, emphysema, air trapping, mediastinal and hilar lymphadenopathy, pulmonary artery enlargement, and pleural effusion.

Transurethral resection of prostatic abscess under sonographic guidance

Transrectal ultrasound may establish the diagnosis of prostatic abscess in an ambiguous clinical setting. Transurethral resection (deroofing) is the treatment preferred by many clinicians, yet intraoperative complete abscess obliteration may be difficult to confirm endoscopically. We report on a patient with a complex prostatic abscess endoscopically resected under transrectal ultrasound guidance. Adequacy of treatment was proved pathologically.