Accuracy of in-vivo assessment of prostatic volume by MRI and transrectal ultrasonography.

More accurate noninvasive estimation of prostate size is important in therapeutic trials for benign prostatic hyperplasia. The accuracy of MRI and transrectal ultrasound (TRUS) in assessing prostate weight was evaluated in 48 patients who underwent radical prostatectomy for stage A or B cancer. The volume derived from the wet weight of the freshly excised specimen was used as a reference. We compared that volume with volume estimates derived from the three-axis linear dimension measurement by MRI and TRUS using a tissue density of 1.05 g/cc and the standard formula for an ellipsoid object. Prostate and seminal vesicle volumes were also computed by contouring T2-weighted 5 mm thick contiguous MR images using a semiautomatic edge detection program and pixel summation. Three-axis volume MRI method versus volume from wet weight has slightly less scatter than TRUS three-axis method (r = 0.85 vs r = 0.81). Contoured MR volume method has the least scatter r = 0.93, statistically better than the linear axis method. Contoured MRI volumetric analysis appears superior to linear MRI or TRUS methods in estimating true prostate volume.     

Computed tomography of hepatic cavernous hemangioma

Fifty hepatic hemangiomas in 38 patients were evaluated by CT using sequential scanning following bolus injection. Lesions were assessed for the following CT features: (a) low density lesion on unenhanced scan; (b) early peripheral contrast enhancement; (c) progressive opacification from the periphery to the center; (d) a delay of at least 3 min before total opacification; and (e) eventual isodense appearance with or without unopacified cleft. The criteria for diagnosis of hepatic hemangioma were (d) and (e) plus at least two of the remaining three features. Forty-eight lesions were identified by CT; 38 displayed all five features, five lesions were missing one feature, and five lesions did not meet the criteria for diagnosis. Larger lesions required a significantly longer period to opacify (p less than 0.05). The positive predictive value of CT in the diagnosis of hemangioma was 100%.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.     

Efficacy of prostate-specific antigen and magnetic resonance imaging in staging stage C adenocarcinoma of the prostate.

OBJECTIVES. The authors compared the two most common presurgical tests now used for the preoperative staging of adenocarcinoma of the prostate, prostate-specific antigen (PSA) and magnetic resonance imaging (MRI). METHODS. One hundred consecutive radical retropubic prostatectomy patients were imaged at 1.5 Tesla before surgery with routine T1-weighted and T2-weighted transaxial images. The images were analyzed by two experienced radiologists for evidence of extracapsular disease. Radiologists rated each gland on a scale of 0 to 100 for the percentage likelihood of extracapsular disease based on its MRI appearance. Receiver operator characteristic (ROC) curves were plotted, and areas were calculated for the two radiologists and the preoperative PSA values. RESULTS. Comparison of the areas of the ROC curves generated from the two radiologists and those from the preoperative PSA values showed no statistical difference. CONCLUSIONS. In this series, radiologic interpretation of body coil MRI studies in those patients chosen for a radical retropubic prostatectomy was no better in staging adenocarcinoma of the prostate than simply using the preoperative PSA values.     

A multicenter clinical trial of gadolite oral suspension as a contrast agent for MRI

The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49–1.18 for reader 1; .46–1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI.     

Effects of Myocardial Water Exchange on T1 Enhancement during Bolus Administration of MR Contrast Agents

Interpretation of first-pass myocardial perfusion studies employing bolus administration of T₁ magnetic resonance (MR) contrast agents requires an understanding of the relationship between contrast concentration and image pixel intensity. The potential effects of myocardial water exchange rates among the intravascular, interstitial, and cellular compartments on this relationship are controversial. We directly studied these issues in isolated, nonbeating canine interventricular septa. Myocardial T₁ was measured three times/s during bolus transit of intravascular (albumin-Gd-DTPA and poly-lysine-Gd-DTPA) and extracellular (gadoteridol) contrast agents. For polylsine-Gd-DTPA, the peak changes in myocardial 1/T₁ (ΔR1) scaled nonlinearly with perfusate contrast concentration whereas a linear relationship would be expected for fast water exchange among the vascular, interstitial, and cellular compartments. For all agents, the peak ΔR1 were much smaller than the values expected on the basis of fast myocardial water exchange. The data demonstrate that in isolated myocardial tissue, myocardial T₁ enhancement during bolus administration of contrast can be strongly affected by myocardial water exchange for both intravascular and extracellular MR contrast agents.     

Comparison of magnetic resonance imaging and ultrasonography in staging early prostate cancer. Results of a multi-institutional cooperative trial

BACKGROUND. In 1987, a cooperative study group consisting of five institutions was formed to determine the relative benefits of magnetic resonance imaging (MRI) and endorectal (transrectal) ultrasonography in evaluating patients with clinically localized prostate cancer (stage Ta or Tb). METHODS. Over a period of 15 months, 230 patients were entered into the study and evaluated with identical imaging techniques. We compared imaging results with information obtained at the time of surgery and on pathological analysis. RESULTS. MRI correctly staged 77 percent of cases of advanced disease and 57 percent of cases of localized disease; the corresponding figures for ultrasonography were 66 and 46 percent (P not significant). These figures did not vary significantly between readers; moreover, simultaneous interpretation of MRI and ultrasound scans did not improve accuracy. In terms of detecting and localizing lesions, MRI identified only 60 percent of all malignant tumors measuring more than 5 mm on pathological analysis and ultrasonography identified only 59 percent. CONCLUSIONS. The MRI and ultrasonography equipment that is currently available is not highly accurate in staging early prostate cancer, mainly because neither technique has the ability to identify microscopic spread of disease. Further evaluation with improved equipment may improve the accuracy of these techniques.     

Computed tomography in the diagnosis of cavernous hemangioma of the liver

Computed tomography (CT), using a sequential timed scanning technique, was performed on six patients with hepatic cavernous hemangiomas. Initial examination shows a moderately homogeneous circumscribed area with reduced attenuation values. Serial scans after injection of a bolus of contrast material show early peripheral opacification while the central part of the lesion retains low attenuation values for several minutes. Later scans demonstrate a variable degree of "filling in" of the central part of the hemangioma. If the characteristic appearance of this lesion is recognized, confusion with other ominous lesions and biopsy can be avoided. Because of limited experience, the described pattern may not be absolutely pathognomonic for hemangioma, so angiography is currently advised to confirm the diagnosis.     

Evaluation of the acceptability of intravaginal prasterone ovule administration using an applicator

The objective of the study is to evaluate the acceptability of the intravaginal administration of ovules/suppositories of DHEA (dehydroepiandrosterone, prasterone) for the treatment of vulvovaginal atrophy (VVA) in women with moderate to severe dyspareunia who were administered daily for 12 weeks intravaginal 0.50% (6.5 mg) DHEA or placebo. There were a total of 373 women in the per-protocol population who responded to the questionnaire for both treatment groups. While it was planned that the applicator would be evaluated as suitable if at least 80% of participants have a global score ≤?2 units, 99% and 100% of participants had a score ≤?2 units in the placebo and DHEA groups, respectively, for the global score (mean of 5 questions). When asked about like and dislike the technique of drug administration, 284 comments were positive, while 114 women gave no comment. About 92–94% of women indicated that they were very confident to be able use the applicator successfully in the future. The survey shows a high degree of satisfaction and of confidence to use the applicator successfully in the future.     

In vivo measurements of airway reactivity using high-resolution computed tomography

Changes in airway resistance are reported to account for only a portion of changes in total lung resistance. The fraction of total lung resistance caused by airway resistance is difficult to quantify in vivo. High-resolution computed tomography (HRCT) has potential application for directly measuring changes in airway size in vivo. In the present investigation, we studied five anesthetized mongrel dogs using HRCT to locate and measure changes in airway area after aerosol histamine challenge in the absence and presence of deep inspiration. We also related changes in total lung resistance to changes in airway area. We found that in all dogs after histamine aerosol challenge, airway area decreased (range, 23 +/- 7 to 67 +/- 5%, mean +/- SEM), and total lung resistance increased (range, 191 to 378%). After deep inspiration (equal to three times tidal volume), four of the five dogs showed further significant decreases in airway area (range, 13 +/- 6 to 71 +/- 8%), whereas all five dogs showed decreases in RL (range, 3 to 35%). The fact that preconstricted airways constricted further after deep inspiration while the measured RL decreased suggests that RL may not always be a reliable indicator of changes in the size of conducting airways larger than 1 mm.