Efficacy and safety of iopromide for excretory urography.

RATIONALE AND OBJECTIVES: Iopromide is a nonionic monomeric contrast agent. Initial laboratory and clinical data have shown that it is relatively safe. Efficacy for excretory urography has been shown to be good, comparable with other low-osmolality agents. The authors attempted to confirm these impressions in a randomized, double-blind comparison with equivalent doses of ioversol and iopamidol. METHODS: Two hundred adult patients undergoing excretory urography were studied. One hundred received iopromide, 40 received ioversol, and 60 received iopamidol (300 mg I/kg) as an intravenous bolus. Urographic films (obtained 1, 5, 15, and 20 minutes after the bolus, and postvoid) were interpreted by an observer blinded to contrast type. Visualization of renal parenchyma, pelvis and calyces, ureters, and bladder was independently assessed as excellent, good, poor, or nonvisualized. Vital signs were recorded before, 30 to 60 minutes after, and 24 hours after injection. Adverse reactions were sought, physical examinations were performed, and standard hematology and serum chemistry values were measured before and 1 day after injection; a 72-hour serum creatinine level was also measured. RESULTS: Ninety-eight percent of visualization scores were good or excellent; no significant differences among iopromide, iopamidol, and ioversol were found, nor were there any significant differences among groups in vital signs. Only one patient experienced a contrast-related physical examination change (subcutaneous extravasation). No significant changes with regard to hematology or serum chemistry values were observed; there was no contrast-induced nephropathy. Mild adverse reactions were experienced by 10% of patients; there were no significant differences in reaction rates among contrast agents. CONCLUSIONS: Iopromide at a dose of approximately 300 mg I/kg is safe and effective as an excretory urographic agent and is comparable in performance with ioversol and iopamidol.

Double-blind study of the safety, tolerance, and diagnostic efficacy of iopromide as compared with iopamidol and iohexol in patients requiring aortography and visceral angiography.

RATIONALE AND OBJECTIVES: Nonionic contrast media have been shown to be more effective, better tolerated, and safer than standard high-osmolality contrast media when given intravascularly. The aim of this study was to assess the diagnostic efficacy, tolerance, and safety of a new nonionic contrast agent, iopromide (370 mg I/mL), in comparison with two available similar agents, iopamidol (370 mg I/mL) and iohexol (350 mg I/mL), in two randomized, double-blind clinical studies of patients undergoing abdominal aortography and visceral angiography. METHODS: The iopromide group included 80 patients, and the comparator group consisted of 36 iopamidol and 45 iohexol patients. The quality and diagnostic efficacy of all three contrast agents was rated equally as either good or excellent. RESULTS: On a scale of 0 (none) to 3 (severe) for heat and pain, respectively, the mean scores were 1.08 and 0.43 for iopromide in comparison with 1.15 and 0.35 for the comparator media. Minor adverse clinical experiences were noted in 23% of the iopromide group versus 20% of the comparator group. Nausea and vomiting were more common in the comparator group (7% versus 3%), and headache was noted only in the iopromide group (4%). There were no clinically significant changes in laboratory values in any group. Three severe adverse experiences occurred, but all were deemed unrelated to the contrast agents. CONCLUSION: Based on the results of this study, iopromide appears to be efficacious, safe, well tolerated, and comparable with iohexol and iopamidol for use in abdominal aortography and visceral angiography.

Bayesian inference for model-based segmentation of computed radiographs of the hand.

We present a method for medical image understanding by computer that uses model-based, hierarchical Bayesian inference to accurately segment imaged anatomy. A first application is a prototype system that automatically segments and measures symptoms of arthridities in hand radiographs. This is potentially useful in radiological diagnosis and tracking of arthridities. Key steps of the model-based, Bayesian inference approach are: (1) prediction of imagery features from 3D models of anatomy, parameterized by population statistics, (2) local image feature extraction in predicted sub-regions, and (3) the use of a probabilistic calculus to accrue results of image processing and image feature matching procedures in support or denial of hypotheses about the imaged anatomy. The prototype system for hand radiograph analysis accurately segments normal and somewhat degenerated hand anatomy. Results are shown of the ability of the automated system to 'fail soft', recognizing when segmentation is inadequate for accurate measurement. This self evaluation capability improves reliability of measurements for potential clinical use.

Characterization of prostate cancer, benign prostatic hyperplasia and normal prostates using transrectal 31phosphorus magnetic resonance spectroscopy: a preliminary report.

We assessed the ability of 31phosphorus (31P) transrectal magnetic resonance spectroscopy to characterize normal human prostates as well as prostates with benign and malignant neoplasms. With a transrectal probe that we devised for surface coil spectroscopy we studied 15 individuals with normal (5), benign hyperplastic (4) and malignant (6) prostates. Digital rectal examination, transrectal ultrasonography and magnetic resonance imaging were used to aid in accurate positioning of the transrectal probe against the region of interest within the prostate. The major findings of the in vivo studies were that normal prostates had phosphocreatine-to-adenosine triphosphate (ATP) ratios of 1.2 +/- 0.2, phosphomonoester-to-beta-ATP ratios of 1.1 +/- 0.1 and phosphomonoester-to-phosphocreatine ratios of 0.9 +/- 0.1. Malignant prostates had phosphocreatine-to-beta-ATP ratios that were lower (0.7 +/- 0.1) than those of normal prostates (p less than 0.02) or prostates with benign hyperplasia (1.1 +/- 0.2, p less than 0.01). Malignant prostates had phosphomonoester-to-beta-ATP ratios (1.8 +/- 0.2) that were higher than that of normal prostates (p less than 0.02). Using the phosphomonoester-to-phosphocreatine ratio, it was possible to differentiate metabolically malignant (2.7 +/- 0.3) from normal prostates (p less than 0.001), with no overlap of individual ratios. The mean phosphomonoester-to-phosphocreatine ratio (1.5 +/- 0.5) of prostates with benign hyperplasia was midway between the normal and malignant ratios, and there was overlap between individual phosphomonoester-to-phosphocreatine ratios of benign prostatic hyperplasia glands with that of normal and malignant glands. To verify the in vivo results, we performed high resolution magnetic resonance spectroscopy on perchloric acid extracts of benign prostatic hyperplasia tissue obtained at operation and on a human prostatic cancer cell line DU145. The extract results confirmed the differences in metabolite ratios observed in vivo. We conclude that transrectal 31P magnetic resonance spectroscopy can characterize metabolic differences between the normal and malignant prostate.

Transrectal probe for 1H MRI and 31P MR spectroscopy of the prostate gland.

A transrectal probe for 1H imaging and 31P MR spectroscopy of the prostate gland is described. The probe is covered with plastic and consists of an insectional portion containing an rf coil and a handle containing a tuning and matching circuit. Using this transrectal probe, 1H MR images and the first 31P MR spectra of the in situ canine prostate were obtained. Serial alterations in prostate size and changes in the ratio of phosphomonoesters to ATP ratio following orchiectomy were observed. Transrectal images of the prostate appear to be superior to conventional whole body coil images in the canine. For the first time a device to obtain high signal-to-noise 1H images and 31P spectra of the in situ prostate has been constructed. This will allow the assessment of transrectal imaging and spectroscopy as tools for medical studies of prostate pathophysiology.

The benefits of combining early radionuclide renal scintigraphy with routine bone scans in patients with prostate cancer.

Based upon the rapid early renal excretion of bone imaging radiopharmaceuticals, we performed a prospective study to determine the use of combining renal evaluation with routine bone scans in 79 consecutive patients with prostate cancer. The radionuclide renal scintigraphy consisted of a 1-minute sequence of 2.5-second frames with a bolus injection of 99mtechnetium-methylene diphosphonate followed by a series of 2-minute images for 24 minutes. Whole body bone scans were performed after a 3-hour delay. All patients had at least 1 confirmatory study with excretory urography (62), ultrasonography (49) or computerized tomography (30). Results were interpreted independently and compared. Ten studies were normal. Radionuclide renal scintigraphy was able to identify 45 of 49 cortical abnormalities (90 per cent) with a false positive rate of 4 per cent. Accuracy of renal cyst detection was only 47 per cent (15 of 32 cases). All acutely obstructed kidneys were identified correctly by radionuclide renal scintigraphy (5 of 5 cases). Of 12 chronically obstructed kidneys 8 (67 per cent) were identified correctly. The 4 missed kidneys were small and nonfunctioning, and they were diagnosed correctly as such but obstruction as the etiology of nonfunction was unidentifiable by radionuclide renal scintigraphy. The false positive rate of obstructive diagnosis by radionuclide renal scintigraphy was 24 per cent (4 of 17 cases). These findings demonstrate that renal evaluation combined with routine bone scanning is an effective screening procedure for renal complications of prostate cancer; no significant abnormalities were missed. The procedure is entirely free of morbidity and does not add to the radiation dose from the bone scan. Furthermore, it is cost-effective, since it avoids the routine need for 2 separate procedures at followup of patients with prostate cancer.

Complex and simple renal cysts: comparative evaluation with MR imaging.

Magnetic resonance (MR) imaging was performed in two groups of patients to determine its usefulness in evaluating fluid-containing renal masses deemed complex with computed tomography (CT). Twenty-two patients in group 1 had indeterminate renal masses by CT, five of which were also indeterminate by ultrasound (US). The results in this group were compared with histologic findings. Group 2 consisted of 20 patients with simple renal cysts diagnosed according to rigid CT criteria. On MR imaging, 11 of the 23 masses in group 1 and 19 of the 20 in group 2 were diagnosed as benign cysts. Fluid within the cyst had long T1 and T2, resulting in a low signal intensity on T1-weighted images. In the 12 remaining lesions in group 1 and in one lesion in group 2, the fluid content was indeterminate and MR did not permit differentiation of cystic renal carcinoma from old hemorrhage or adenoma. When fluid within the cystic mass did not have the MR characteristics of simple fluid, MR was not helpful in characterizing the mass, but when the fluid intensity was similar to normal urine, the cyst was benign.

Magnetic resonance imaging in the diagnosis and staging of renal and perirenal neoplasms.

Thirty-one adult patients underwent magnetic resonance (MR) imaging after CT scans had demonstrated findings consistent with renal cell carcinoma. MR images were interpreted prospectively and independently of the CT findings. Because the CT scanning was performed at multiple institutions by many examiners, this study was not a direct comparison of CT versus MR. The preoperative diagnoses and staging of the neoplasms, as judged by MR, were compared with those obtained at laparotomy (n = 28), autopsy (n = 1), or biopsy (n = 2). Correct preoperative diagnoses were rendered in 31 patients (100%) on the basis of MR findings. The anatomic staging of 27 renal cell carcinomas was correctly performed by MR in 26 patients (86%). When compared with results of previous studies of the value of CT in the diagnosis and staging of renal neoplasms, MR appears to have several advantages in determination of the origin of the mass; the evaluation of vascular patency; the detection of perihilar lymph node metastases; and the evaluation of direct tumor invasion of adjacent organs. MR is sensitive in determining the extent of tumor thrombus and in evaluating invasion of the inferior vena caval wall. MR should assume an important role in the diagnosis and staging of renal neoplasms.

Anatomy and pathology of the male pelvis by magnetic resonance imaging.

Magnetic resonance imaging (MRI) of the male pelvis was performed in 25 subjects: five normal volunteers; six patients with carcinoma of the bladder; nine with benign nodular hyperplasia (including five with concomitant bladder carcinoma); nine with prostatic carcinoma; and one with a lymphocele after radical prostatectomy. The display of normal anatomy is enhanced by the ability of the MRI device to provide images in direct transverse, sagittal, and coronal planes. Sessile and pedunculated types of bladder carcinoma are readily shown due to the superior ability of MRI for soft-tissue characterization. Direct sagittal scans are advantageous for evaluation of tumors at the bladder base, and by combining two different planes of images, the extent of the neoplasm is better delineated. In the analysis of the prostate, MRI displays the gland in three dimensions and therefore allows accurate volumetric measurements. The greatest potential of MRI seems to be its ability to detect pathology confined to the gland. However, it is not yet known if a neoplastic nodule can be differentiated from chronic prostatitis. Unlike x-ray CT, metallic clips produce no streaking artifacts, giving MRI a definite advantage in the evaluation of patients after radical surgery. These observations were made on a small number of patients. If the results are confirmed with a larger number of patients, MRI will assume a prominent role in the clinical evaluation of bladder and prostate cancer.

Evaluation of plain abdominal radiographs in the diagnosis of abdominal pain.

In an effort to develop referral criteria for the ordering of abdominal radiographs for patients presenting with abdominal symptoms, we prospectively studied the relation between clinical data and radiographic abnormalities. Of 1780 examinations, 179 (10.0%) showed some radiographic abnormality. If abdominal radiographs would have been limited to those patients who had moderate or severe abdominal tenderness, or to patients with a high clinical suspicion of bowel obstruction, renal or ureteral calculi, trauma, ischemia, or gallbladder disease, regardless of the degree of tenderness, 956 (53.7%) examinations would not have been done. All radiographic abnormalities reflecting a serious pathologic process would have been identified. Only 33 (3.5%) abnormalities of limited significance, almost all localized or generalized ileus, would have been undetected. The adoption of these referral criteria would result in minimal loss of clinically useful information, large financial savings, and a reduction in radiation exposure.

Evaluation of plain abdominal radiographs in the diagnosis of abdominal pain.

In an effort to develop referral criteria for the ordering of abdominal radiographs for patients presenting with abdominal symptoms, we prospectively studied the relation between clinical data and radiographic abnormalities. Of 1780 examinations, 179 (10.0%) showed some radiographic abnormality. If abdominal radiographs would have been limited to those patients who had moderate or severe abdominal tenderness, or to patients with a high clinical suspicion of bowel obstruction, renal or ureteral calculi, trauma, ischemia, or gallbladder disease, regardless of the degree of tenderness, 956 (53.7%) examinations would not have been done. All radiographic abnormalities reflecting a serious pathologic process would have been identified. Only 33 (3.5) abnormalities of limited significance, almost all localized or generalized ileus, would have been undetected. The adoption of these referral criteria would result in minimal loss of clinicall useful information, large financial savings, and a reduction in radiation exposure.

Preliminary radiograph for barium enema examination: is it necessary?

In a study of 200 barium enema examinations, the value of the preliminary radiograph, both in demonstrating abnormalities not detectable on the contrast radiographs and in showing the amount of residual fecal material in the colon, was assessed. No clinically significant abnormalities were seen on the preliminary film alone. Estimation of residual fecal material from the preliminary radiograph was frequently faulty and could have resulted in needless additional preparation of patients. This study suggests that inclusion of the preliminary radiograph does not affect the overall diagnostic accuracy of the barium enema examination. Its elimination would yield large savings in health care costs and radiation exposure.

Optimum radiographic examination for consideration of compensation awards: III. Knee, hand and foot.

In a large Veterans Administration (VA) hospital, a prospective study was undertaken to determine the optimum number of radiographic projections needed to assess applicants for VA compensation for knee, hand, and foot diseases or injury claimed to be service-related. Results show that the final radiographic assessment could be made in all 535 (100%) of the knee examinations using two views (anteroposterior and lateral), all 181 (100%) of the hand examinations using one view (anteroposterior), and all 223 (100%) of the foot examinations using two views (anteroposterior and lateral). Extrapolating these results to data on compensation examinations performed in the entire VA system (fiscal year 1978), it was concluded that limiting the radiographic examinations of the knee, hand, and foot to these views would eliminate 91,000 radiographs in the evaluation of 119,000 applicants and yield an annual savings of about $500,000.

Optimum radiographic examination for consideration of compensation awards: I. General methodology and application to chest examination.

A major goal of the radiologist is to devise methods to decrease health care costs and radiation exposure without sacrificing diagnostic accuracy. In a large Veterans Administration (VA) hospital, a prospective study was undertaken to determine the optimum number of radiographic projections needed to assess applicants for VA compensation for chest disease or injury claimed to be service-related. Three separate readings of every chest radiographic assessment could have been made from a single posteroanterior view. In eight cases, granulomas or mild hyperexpansion of the lungs were only appreciated using the lateral projection, but these findings were not clinically significant and did not affect decisions as to whether compensation sould be awarded. The only potentially serious lesion missed (a possible pulmonary nodule) using the posteroanterior view alone was also missed using the lateral and only suggested by the oblique views. Extrapolating these results to data on compensation examinations performed in the entire VA system (fiscal year 1978), it was concluded that limiting the radiographic examination of the chest to a single posteroanterior view would eliminate 150,000 radiographs in the evaluation of 190,000 applicants and yield an annual savings of almost $900,000.

Optimum radiographic examination for consideration of compensation awards: II. Cervical and lumbar spines.

In a large Veterans Administration (VA) hospital, a prospective study was undertaken to determine the optimum number of radiographic projections needed to assess applicants for VA compensation for cervical and lumbar spine disease or injury claimed to be service-related. Results show that the final radiographic assessment could be made in 100% (245) of cervical spine examinations using two views (anteroposterior and lateral) and in 99.3% (699/704) of lumbar spine examinations using two views (anteroposterior and a single well centered lateral). Extrapolating these results to data on compensation examinations performed in the entire VA system (fiscal year 1978), it was concluded that limiting the radiographic examinations of the cervical and lumbar spines to these views would eliminate 193,000 radiographs in the evaluation of 100,000 applicants and yield an annual savings of about $1,000,000.

Neurologic complications of angiography in patients with critical stenosis of the carotid artery.

We retrospectively studied 85 patients with angiographically demonstrable critical carotid stenosis. None suffered either immediate or delayed complications after angiography. In patients with critical stenosis of the carotid artery, the benefits of cerebral angiography clearly outweigh the small potential risk when the procedure is performed with meticulous attention to technical detail.

Neurologic complications of angiography for cerebrovascular disease.

A recent study reported a 12.2% incidence of cerebral complications (5.2% permanent) after cerebral angiography in 147 patients. Because this was markedly different from our experience, we initiated a retrospective study of 301 patients who had undergone cerebral angiography for hemisphere transient ischemia or amaurosis fugax. There was only a 1.3% rate of transient complications (none permanent) in our patients. The benefits of cerebral angiography in patients with suspected cerebrovascular occlusive disease overwhelm the small potential risk of the procedure.