Ductal carcinoma in situ diagnosed with stereotactic core needle biopsy: can invasion be predicted?

PURPOSE

To determine whether mammographic or histologic features can be used to predict which cases diagnosed as ductal carcinoma in situ (DCIS) without invasion by means of stereotactic core needle biopsy (SCNB) will have invasive disease at surgery.

MATERIALS AND METHODS

From July 1992 to March 1999, DCIS without invasion was diagnosed by means of SCNB in 59 patients. Seventeen (29%) were found to have invasive disease after surgery. The underestimation rate for SCNB was compared with that obtained by means of open surgical biopsy. Mammographic and histologic features of cases with and those without invasion were compared.

RESULTS

All patients had calcifications on mammograms. There was no significant difference (P: =.26) between the underestimation rate for SCNB with the 11-gauge vacuum-assisted device and that for open surgical biopsy. No statistically significant differences between cases with and those without invasion were seen in patient age, mean number of core specimens, level of suspicion, size of lesion, distribution and morphology of the calcifications, presence of an associated mass or density, subtype of DCIS, nuclear grade, or presence of necrosis or desmoplasia.

CONCLUSION

Mammographic and histologic features cannot be used reliably to predict cases that are underestimated with SCNB. However, SCNB with the 11-gauge vacuum-assisted device was as reliable as open surgical biopsy for diagnosing DCIS without invasion.

Underestimation of breast cancer with II-gauge vacuum suction biopsy

OBJECTIVE

The purpose of this study was to determine the mammographic and histologic features of cancerous lesions underestimated using 11-gauge vacuum suction biopsy.

MATERIALS AND METHODS

Retrospective review of 11-gauge vacuum suction biopsy was performed to identify lesions diagnosed as atypical ductal hyperplasia or carcinoma. The histology of the core and surgical specimens was compared. Of 158 cases of cancer, underestimation occurred in 15 (9.5%). The mammographic and histologic features were assessed.

RESULTS

Of 15 underestimated cases, six were atypical ductal hyperplasia that proved to be cancer (5 ductal carcinoma in situ and 1 invasive) and nine were ductal carcinoma in situ that proved to have invasion. The underestimation rate for calcifications was 16.3% (14/86) and for masses was 1.6% (1/64) (p = 0.007). Most (5/6) underestimated atypical ductal hyperplasia cases were reported as "markedly atypical," and four of nine underestimated ductal carcinoma in situ cases were reported as "possible invasion." No significant difference was seen in the number of core specimens obtained or the sizes of the lesions for underestimated cases versus accurately diagnosed cases. The percentage of calcifications retrieved was significantly different (p = 0.017). No underestimations were found among cases in which the entire mammographic lesion was removed at vacuum suction biopsy.

CONCLUSION

The cancer underestimation rate with vacuum suction biopsy was 9.5%. The underestimation rate for calcifications (16.3%) was significantly higher than that for masses (1.6%) (p = 0.007). The percentage of the lesion removed was an important factor in reducing underestimation, as reflected by the percentage of calcifications retrieved and the instances of complete resolution of the lesion seen on mammography.

Patient perception of magnetic resonance arthrography

OBJECTIVE

Magnetic resonance (MR) arthrography has been demonstrated to be more accurate than MR imaging alone in the identification of a variety of musculoskeletal pathology. While the complication rate of intra-articular gadolinium: saline injection has been shown to be relatively low, MR arthrography is more invasive, painful, and costly, and less convenient, than MR imaging alone. The purpose of this study was to evaluate patients' perception of the fear and discomfort, and to assess their overall acceptance of the intra-articular gadolinium injection.

DESIGN AND PATIENTS

Between October 1997 and January 1998, 113 outpatients who were referred to Yale-New Haven Hospital for MR arthrography of the ankle, elbow, hip, knee, shoulder, or wrist were asked to complete a questionnaire rating their fear of factors most commonly associated with the procedure including "pain", "needles", "complications", and "discovery of results that would lead to surgery". In addition, after having undergone the intra-articular gadolinium:saline injection, patients were asked to rate their perception of pain.

RESULTS

While many patients expressed fear of "pain" and "needles", after having undergone the injection their overall pain rating score was low. Only 6% actually found gadolinium arthrography more painful than expected.

CONCLUSION

Despite the fact that patients expressed apprehension about certain aspects of MR arthrography, subjects who underwent the intra-articular gadolinium injection considered the discomfort less than expected. Clinicians should not hesitate to order MR arthrography because the accuracy of the procedure is high enough that patients accept the discomfort.

Comparison of rebiopsy rates after stereotactic core needle biopsy of the breast with 11-gauge vacuum suction probe versus 14-gauge needle and automatic gun

OBJECTIVE

The 11-gauge vacuum suction probe is an alternative to the 14-gauge needle and automatic gun for performing stereotactic core needle biopsies. This study compares rebiopsy rates after stereotactic core needle biopsies that were performed with the two methods. The study also assesses the outcomes of those repeat biopsies.

MATERIALS AND METHODS

Five hundred ninety-two stereotactic core needle biopsies using a 14-gauge needle and automatic gun and 354 using an 11-gauge vacuum suction probe were performed consecutively. Excluding malignancies, the number of cases requiring rebiopsy and the reasons for rebiopsy were determined for each group. The histologic diagnoses of the repeat biopsies were assessed.

RESULTS

The rebiopsy rate was significantly lower with the 11-gauge vacuum suction probe (9.0%) than with the 14-gauge needle and automatic gun (14.9%) (p = .013). Significant reductions were found in cases of insufficient sampling (probe, 1.7%; needle, 4.4%; p = .042) and mammographic-pathologic discrepancy (probe, 0.8%; needle, 3.4%; p = .026). The rebiopsy rate for masses was 6.1% with the vacuum probe versus 10.7% with the 14-gauge needle (p = .12) and for calcifications was 11.6% with the vacuum probe versus 23.7% with the 14-gauge needle (p = .003). After rebiopsy, the percentage of cases in which malignancy was found was 18.5% with the vacuum probe versus 13.7% with the 14-gauge needle. On rebiopsy, the percentage of malignancies found in each category were atypical hyperplasia: probe 26.7%, needle 20.0%; insufficient sample: probe 0%, needle 9.5%; pathologist recommendation: probe 50.0%, needle 12.5%; and lobular carcinoma in situ: probe 0%, needle 100%.

CONCLUSION

Use of the 11-gauge vacuum-assisted device significantly decreases but does not eliminate the need for rebiopsy after stereotactic core needle biopsy. The rebiopsy rate for calcifications was significantly reduced by using the vacuum suction probe rather than the 14-gauge needle; however, the rate for masses was reduced only slightly. On rebiopsy, malignancies were found in both groups.

Pneumothorax and dependent versus nondependent patient position after needle biopsy of the lung

PURPOSE

To test the hypothesis that placing the patient in a position with the puncture site dependent (down) after transthoracic needle biopsy reduces the incidences of pneumothorax and of pneumothorax that requires chest tube placement.

MATERIALS AND METHODS

Four hundred twenty-three needle biopsies of the lung were performed in 390 patients from October 1991 to August 1994 with computed tomographic guidance, fluoroscopic guidance, or both. Two hundred forty-two biopsies were performed from the posterior approach, 166 from the anterior approach, and 15 from the lateral approach. The patients were assigned on an alternating basis to either the puncture-site-dependent recumbent position (210 biopsies) or the puncture-site-nondependent recumbent position (213 biopsies) for at least 1 1/2 hours after biopsy.

RESULTS

No significant differences were found in either the incidence of pneumothorax (dependent position, 62 of 210 biopsies [30%], vs nondependent position, 57 of 213 biopsies [27%]; P = .60) or the incidence of pneumothorax that required chest tube placement (dependent position, 10 of 210 biopsies [5%], vs nondependent position, six of 213 biopsies [3%]; P = .43).

CONCLUSION

The results suggest that the puncture-site-down postbiopsy position may not affect either the incidence of postbiopsy pneumothorax or the incidence of pneumothorax that requires chest tube placement.

Delta-9-tetrahydrocannabinol delays the gastric emptying of solid food in humans: a double-blind, randomized study

BACKGROUND

Delta-9-tetrahydrocannabinol (THC), the active constituent of marijuana, is an effective agent in the prevention of chemotherapy-induced nausea and vomiting.

AIM

To determine the effect of THC on gastric emptying of a radiolabelled solid food in humans.

METHODS

Thirteen healthy volunteers underwent gastric emptying studies after receiving THC and placebo in a randomized double-blind fashion on 2 separate days. THC, at a dose of 10 mg/m2 of body surface area, or placebo were administered.

RESULTS

Gastric emptying after THC was slower than placebo in all subjects. Mean percentage of isotope remaining in the stomach was significantly greater than after placebo from 30 min (85.5 +/- 4.3% vs. 94.2 +/- 1. 4% placebo and THC, respectively, P < 0.05) to 120 min (45.6 +/- 7. 2% vs. 73.9 +/- 7.1% placebo and THC, respectively, P < 0.001) after the test meal. No correlation was found between plasma THC levels and the delay in gastric emptying.

CONCLUSIONS

THC at a dose used for preventing chemotherapy-induced nausea and vomiting significantly delays gastric emptying of solid food in humans. Therefore, the anti-emetic property of THC may be mediated through the central nervous system.

Prevalence of impaired gastric emptying of solids in systemic sclerosis: diagnostic and therapeutic implications

The aims of this study were to evaluate the gastric emptying of solids in patients with progressive systemic sclerosis, correlate the esophageal motility abnormalities with their gastric emptying status, delineate the symptoms suggestive of abnormal gastric emptying, and assess the effect of metoclopramide in patients with abnormally slow gastric emptying. Twenty patients underwent esophageal motility evaluation and gastric emptying studies with a radiolabeled solid meal. Gastric emptying was also measured in 13 healthy volunteers. Four patients in whom esophageal motility was normal also had an accompanying normal rate of gastric emptying. In 16 patients with abnormal esophageal motility, mean gastric emptying was significantly delayed as compared with that in normal subjects (67.4% vs 49.8% retention of isotope at 2 hours, P < .05). Ten patients had absolute criteria for slow gastric emptying (>+2 SD). However, only postprandial bloating and early satiety were symptoms that accurately predicted slow radionuclide emptying. In four of these patients in whom gastric emptying was slow, 10 mg intramuscular metoclopramide significantly (P < .05 vs baseline) accelerated the gastric emptying of the same test meal. We conclude that (1) gastric emptying of solids was delayed in approximately two thirds of patients with abnormal esophageal motility, whereas it was normal in patients with normal esophageal motor function; (2) metoclopramide significantly accelerated this slow gastric emptying; and (3) delayed gastric emptying contributes to the severity of the gastroesophageal reflux frequently present in patients with progressive systemic sclerosis, and promotility agents offer a valuable therapeutic approach.

Transrectal sonography in staging rectal carcinoma: the role of gray-scale, color-flow, and Doppler imaging analysis

OBJECTIVE

The purpose of this study was to evaluate the efficacy of combining gray-scale sonography with color-flow imaging and pulsed Doppler transrectal sonography in the staging of rectal carcinoma.

SUBJECTS AND METHODS

Thirty-nine patients with primary rectal carcinoma underwent transrectal sonography. The rectal masses were staged T1-T2 or T3-T4 on the basis of gray-scale imaging. The local nodes were classified as benign or malignant on the basis of size and echogenicity. In 22 patients, color-flow imaging and pulsed Doppler imaging of the rectal mass and of the local lymph nodes were performed. The peak systolic velocity (PSV) and end diastolic velocity were documented, and the resistive index was calculated.

RESULTS

Gray-scale imaging alone was used to stage T1-T2 masses with 88% sensitivity and 82% specificity. T3-T4 masses were staged with 82% sensitivity and 88% specificity. Overall accuracy was 85%. Gray-scale imaging of lymph nodes using a discriminatory size of less than or equal to 5 mm for benign nodes and greater than 5 mm for malignant nodes yielded a sensitivity of 100%, a specificity of 28%, and an accuracy of 52%. Using receiver operating characteristic curve analysis, we determined that a size of greater than or equal to 7 mm was optimal for characterizing nodes. Such a size provided an accuracy of 83%. PSV of less than 25 cm/sec distinguished T3-T4 from T1-T2 rectal masses with 75% sensitivity, 80% specificity, and 77% accuracy. A PSV of greater than 20 cm/sec classified a node as malignant with 100% sensitivity, 62% specificity, and 76% accuracy. A resistive index of greater than 0.61 classified a node as malignant with 71% sensitivity, 85% specificity, and 80% accuracy.

CONCLUSION

Color-flow imaging and pulsed Doppler imaging are useful additions to gray-scale transrectal sonography in staging primary rectal carcinomas. The combination has most value when evaluating perirectal nodes.

Economic impact of replacing CT with MR imaging for refractory epilepsy

PURPOSE

To evaluate the economic costs of using computed tomography (CT) vs. magnetic resonance (MR) imaging in the preoperative evaluation of refractory epilepsy patients.

METHODS

Preoperative CT and MR imaging findings from 117 patients who underwent surgery for medically refractory epilepsy during a 3.5-year period were reviewed. Cost savings were based on the paradigm that intracranial electroencephalogram monitoring (costing about $50,000) would have been necessary for preoperative localization of the epileptogenic zone in those patients without positive imaging findings. Savings attributed to replacing CT with MR were based on patients with positive MR and normal CT. A similar paradigm was used to calculate savings for replacing MR with CT. National savings were based solely on patients with neoplasms or vascular lesions because paradigms for other lesions vary considerable depending on institutional philosophy.

RESULTS

Replacing CT with MR imaging would have eliminated preoperative intracranial electrode procedures in 29 of 117 patients, with potential savings of $1,450,000 at our institution. In the 37 patients with neoplastic or vascular substrates, MR would have eliminated 10 invasive electrode procedures with estimated savings of $0.5 million institutionally and $3 to $4 million per year nationally. There were no cases to support replacing MR with CT.

CONCLUSION

Replacing CT with MR decreases health costs associated with preoperative evaluation of intractable epilepsy requiring surgical amelioration.

Qualitative MR imaging of refractory temporal lobe epilepsy requiring surgery: correlation with pathology and seizure outcome after surgery

OBJECTIVE

The purpose of this study was to compare MR imaging findings with histologic findings of either hippocampal sclerosis or gliosis in patients with intractable temporal lobe epilepsy requiring surgery and to correlate MR imaging findings with seizure outcome after surgery and with clinical parameters such as febrile seizure history.

MATERIALS AND METHODS

A retrospective study of MR scans of 66 patients with medically refractory temporal lobe epilepsy requiring surgery was performed. Qualitative diagnosis was done by visual inspection of MR images. MR imaging findings of hippocampal atrophy, signal intensity changes, and segmental findings were correlated with histopathology and with neuronal density. The final MR imaging diagnosis was also correlated with seizure outcome after surgery and with febrile seizure history.

RESULTS

Histologic findings consisted of hippocampal sclerosis in 55 patients and nonspecific gliosis in 11 patients. Two variables, MR imaging findings of hippocampal sclerosis (hippocampal atrophy or signal intensity change) and a febrile seizure history, were significantly associated with hippocampal sclerosis. MR images of nonspecific gliosis usually showed normal findings, although some cases showed mild hippocampal atrophy. When comparing MR imaging findings with histology, our observers achieved sensitivities of 87-98% and specificities of 45-100%. In patients with successful outcomes after surgery, sensitivity ranged from 85% to 98% for MR imaging findings suggesting hippocampal sclerosis, specificity ranged from 17% to 85%, and positive predictive values ranged from 82% to 90%.

CONCLUSION

Qualitative visual analysis of MR images correlates well with histologic findings, febrile seizure history, and seizure outcome after surgery. MR imaging findings and febrile seizure history help differentiate between hippocampal sclerosis and nonspecific gliosis, two similar clinical conditions associated with temporal lobe epilepsy that often have different outcomes after surgery.

Fibroma and fibrothecoma of the ovary: MR imaging findings

PURPOSE

To describe the morphologic and signal intensity characteristics on magnetic resonance (MR) images of fibromas and fibrothecomas.

MATERIALS AND METHODS

MR images of 11 female patients with histologically proved fibromas or fibrothecomas were reviewed, and morphologic and signal intensity characteristics of the lesions were analyzed. MR imaging findings were correlated with histologic findings.

RESULTS

All fibromas and fibrothecomas showed homogeneous low signal intensity on T1-weighted images. On T2-weighted images, the two smallest lesions showed homogeneous low signal intensity, and eight of the other nine lesions showed predominantly low signal intensity. Edema was noted only in larger lesions, and cystic degeneration was noted only in three of the largest lesions. On T2-weighted images, the percentage of low signal intensity in the lesion was not found to be related to lesion size, and the percentage of low signal intensity in fibromas was not significantly different from that in fibrothecomas (P = .55). Many lesions showed heterogeneous signal intensity; the solid component was distributed peripherally, and the cystic component was located centrally or eccentrically. Free intraperitoneal fluid was noted in 10 of 11 lesions and was not significantly correlated with lesion size (r = .52 and P = .10).

CONCLUSION

Because of their predominantly low signal intensity on T2-weighted images, fibromas and fibrothecomas display a relatively specific appearance on MR images.

Rotator cuff: evaluation with fast spin-echo versus conventional spin-echo MR imaging

PURPOSE

To determine if fast spin-echo (SE) magnetic resonance (MR) imaging can provide similar information to that of conventional SE imaging for evaluation of the rotator cuff.

MATERIALS AND METHODS

One hundred twenty-six patients underwent MR imaging with conventional SE and non-fat-suppressed fast SE sequences (65 patients) or conventional SE and fat-suppressed fast SE sequences (61 patients). Two radiologists independently graded the rotator cuff with separate and side-by-side assessment of the fast SE and conventional SE images.

RESULTS

For detection of full-thickness tears, agreement between non-fat-suppressed fast SE and conventional SE images was 93.8% (kappa = 0.78 [good]) and 95.4% (kappa = 0.82 [very good]) for the two readers, respectively, and agreement between fat-suppressed fast SE and conventional SE images was 98.4% (kappa = 0.96 [very good]) and 91.8% (kappa = 0.73 [good]) for the two readers, respectively. Rotator cuff grading was similar for fast SE and conventional SE: weighted kappa = 0.77 (good) and 0.68 (good) for non-fat-suppressed and weighted kappa = 0.83 (very good) and 0.67 (good) for fat-suppressed fast SE images for the two readers, respectively.

CONCLUSION

Fast SE sequences yield similar interpretations as those obtained with a conventional SE sequence for evaluation of the rotator cuff.

Chest radiograph interpretation of Pneumocystis carinii pneumonia, bacterial pneumonia, and pulmonary tuberculosis in HIV-positive patients: accuracy, distinguishing features, and mimics

The purpose of this study was to assess the accuracy of chest x-ray (CXR) interpretation in the diagnosis of pneumocystis carinii pneumonia (PCP), bacterial pneumonia (BP), and pulmonary tuberculosis (TB) in human immunodeficiency virus (HIV)-positive patients and to identify the frequency with which these infections mimic one another radiographically. The admitting CXRs of 153 HIV-positive patients with laboratory proven BP (n = 71), PCP (n = 73), and TB (n = 9) and those of 10 HIV-positive patients with no active disease were reviewed retrospectively and independently by three radiologists who were blinded to clinical and laboratory data. Median percent accuracies were as follows: TB, 84%; PCP, 75%; BP, 64%; and no active disease, 100%. Fifteen of 153 cases (9.8%) were shown to mimic other infections radiographically. A confident and accurate diagnosis can be made radiographically in the majority of cases of PCP, BP, and TB in HIV-positive patients at the time of hospitalization. In approximately 10% of cases, these infections may mimic one another radiographically.

Mammographic findings of recurrent breast cancer after lumpectomy and radiation therapy: comparison with the primary tumor

PURPOSE

To compare the mammographic findings of recurrent breast cancer with those of the primary tumor in patients who underwent lumpectomy and radiation therapy.

MATERIALS AND METHODS

Mammograms were reviewed of primary and recurrent tumors in 25 patients (26 lesions). Mammographic appearance, location, and histopathologic characteristics were retrospectively compared between primary and recurrent tumors.

RESULTS

Primary and recurrent tumors were mammographically similar in 21 (81%) of the 26 lesions. Of 14 primary tumors with calcifications, 12 (86%) recurred with calcifications, and of the 12 masses, nine (75%) recurred as masses. Recurrent tumors that occurred in the lumpectomy quadrant were more often similar in mammographic appearance to the primary tumor (20 of 22 tumors) than those in other quadrants (one of four tumors) (P < .02).

CONCLUSION

After conservative treatment of breast cancer, the majority of recurrent tumors appear to be mammographically similar to primary tumors. It is prudent to review preoperative mammograms during follow-up of patients after lumpectomy and radiation therapy.

Conspicuity of normal and pathologic female pelvic anatomy: comparison of gadolinium-enhanced T1-weighted images and fast spin echo T2-weighted images

PURPOSE

Our goal was to compare the conspicuity of normal and pathologic female pelvic anatomy between gadolinium-enhanced T1-weighted images and fast SE (FSE) T2-weighted images.

METHOD

In 48 consecutive female patients, pre- and postenhanced T1-weighted images were compared with FSE T2-weighted images acquired with a phased array coil. Normal zonal anatomy (ZA) and pathologic abnormalities in gadolinium-enhanced T1-weighted images were rated as increased, decreased, or without change in conspicuity as compared with FSE T2-weighted images.

RESULTS

The normal ZA of the uterine corpus on T1-weighted images showed a decrease in conspicuity in 93% of patients and an increase in 7% compared with FSE T2-weighted images. Conspicuity of cervical ZA on T1-weighted images was decreased in 86%, increased in 6%, and without change in 8% as compared with FSE T2-weighted images. ZA of the vagina on T1-weighted images was decreased in 94% and increased in 6% as compared with FSE T2-weighted images. On T1-weighted images, ovarian anatomy delineation was decreased in 95% and increased in 5% as compared with FSE T2-weighted images. Conspicuity of malignant pathologic abnormalities on T1-weighted images was decreased in 81%, increased in 11%, and without change in 8% as compared with FSE T2-weighted images. In patients with benign disease, conspicuity on T1-weighted images was decreased in 92%, increased in none, and without change in 8% as compared with FSE T2-weighted images. The p value for all categories was < 0.0001.

CONCLUSION

Conspicuity of both normal and pathologic anatomy was significantly decreased on enhanced T1-weighted images. The use of gadolinium cannot replace T2-weighted scans for delineation of anatomy and disease and should be reserved to cases in which standard imaging sequences are not sufficiently diagnostic.

Refractory epilepsy: comparison of MR imaging, CT, and histopathologic findings in 117 patients

PURPOSE

We compared computed tomography (CT) and magnetic resonance (MR) imaging for the detection of abnormalities underlying epilepsy.

MATERIALS AND METHODS

CT and MR imaging findings in 117 patients (56 female, 61 male patients; age at surgery, 12-56 years) who underwent surgery for medically refractory epilepsy were compared with histopathologic findings by using the McNemar and chi 2 statistics.

RESULTS

Sensitivities for detecting abnormalities were 95% (104 of 109) for MR imaging and 32% (35 of 109) for CT; specificities were 87% (13 of 15) for MR imaging and 93% (14 of 15) for CT (P < .001 for MR versus histopathologic findings). In the subgroup of 113 patients with solitary findings, MR imaging depicted an abnormality at the surgical site in 86% (n = 97) of 113 patients compared to 28% (n = 32) for CT (P < .001). In this same subgroup, histopathologic findings were predicted by using MR imaging in 88% (n = 99) of 113 patients versus 35% (n = 40) with CT (P < .001). Multiple findings were observed in 3% of CT (three of 117) and 17% of MR (20 of 117) images.

CONCLUSION

CT has no role in the diagnostic evaluation of medically refractory epilepsy. Even in patients with medically controlled epilepsy, use of less costly CT instead of MR imaging seems imprudent.

Stereotaxic core needle biopsy of breast microcalcifications: correlation of target accuracy and diagnosis with lesion size

PURPOSE

To determine if lesion size or number of calcifications affects the ability to obtain microcalcifications or a specific histologic diagnosis at stereotaxic core needle biopsy (SCNB).

MATERIALS AND METHODS

Mammographic findings and histopathologic reports of 138 lesions in 124 patients (aged 30-87 years; mean age, 56.2 years) who underwent SCNB of calcifications were reviewed. Calcifications in the specimen and attainment of a specific diagnosis were correlated with lesion size and number of calcifications.

RESULTS

Calcifications were obtained in 118 cases (86%). A specific diagnosis was reported in 72 cases (52%). Differences in retrieval of calcifications or ability to establish a specific diagnosis with decreasing lesion size or decreasing number of calcifications were not statistically significant. Attainment of a specific diagnosis was significantly related to retrieval of calcifications (P<.005).

CONCLUSION

SCNB was successful in obtaining calcifications in a high percentage of cases regardless of lesion size or number of calcifications. When calcifications were retrieved, a specific diagnosis was attained in most cases (72 of 118).

Acute flank pain: comparison of non-contrast-enhanced CT and intravenous urography

PURPOSE

To compare non-contrast-enhanced computed tomography (CT) and intravenous urography (IVU) in the evaluation of patients who present with acute flank pain and in whom ureteric obstruction is suspected.

MATERIALS AND METHODS

The findings at non-contrast-enhanced CT and IVU in 20 patients with acute flank pain were compared for the presence or absence of ureteric obstruction and delineation of ureteric stones.

RESULTS

Twelve of the 20 patients had non-contrast-enhanced CT and IVU findings consistent with ureteric obstruction. Of these 12 patients, five had a ureteric stone that was demonstrated on both non-contrast-enhanced CT scans and IVU radiographs, six had a stone that was depicted on non-contrast-enhanced CT scans only, and in one patient a stone could not be delineated definitively on either non-contrast-enhanced CT scans or IVU radiographs. Eight patients had findings at non-contrast-enhanced CT and IVU consistent with the absence of obstruction.

CONCLUSION

Non-contrast-enhanced CT is more effective than IVU in precisely identifying ureteric stones and is equally effective as IVU in the determination of the presence or absence of ureteric obstruction.

Clinical stage I endometrial carcinoma: pitfalls in preoperative assessment with MR imaging. Work in progress

PURPOSE

To identify potential pitfalls in using magnetic resonance (MR) imaging to determine the depth of myometrial invasion in patients with clinical stage I endometrial carcinoma.

MATERIALS AND METHODS

Forty women with clinical stage I endometrial carcinoma underwent preoperative pelvic MR imaging. Uterine length, tumor signal intensity, appearance of the junctional zone, presence of large polypoid tumors, leiomyomata, and congenital uterine anomalies were analyzed. Univariate logistic-regression analysis was performed to identify associations between incorrect MR staging and these variables.

RESULTS

MR staging of IA, IB, and IC disease was 55% accurate (22 of 40 cases); MR differentiation of deep myometrial invasion (stage IC) from superficial disease (stages IA and IB) was 78% accurate (31 of 40 cases). Older age (P = .025), presence of polypoid tumors (P = .025), and difficulty in pathologic staging (P < .005) were significantly associated with incorrect MR assessment.

CONCLUSION

When present, large polypoid tumors, leiomyomata, congenital anomalies, small uteri, and indistinct zonal anatomy may make it difficult to assess myometrial invasion at MR imaging.

MR characteristics of neoplasms and vascular malformations associated with epilepsy

We assessed the magnetic resonance (MR) imaging characteristics of two categories of epileptogenic substrates, neoplasms, and vascular malformations, to determine MR sensitivity and typical imaging features. A blinded retrospective analysis was performed on MR scans from 41 patients who had a neoplasm or vascular malformation surgically resected as treatment for medically refractory epilepsy. Abnormalities were assessed for sensitivity of MR detection, prediction of pathologic category, location, calvarial remodelling, signal intensity, and effect on adjacent tissue. Pathologic findings consisted of 33 tumors and 8 vascular malformations. We correctly localized 100% of the 41 lesions and predicted the correct pathologic category for 95% of these lesions. Neoplastic and vascular lesions (NVLs) associated with epilepsy had certain characteristic features. The temporal lobe was the most common site for NVL, involved in 68%. NVL were located in the brain periphery in 85% and remodelled the calvarium in 32%. NVL were associated with mass effect in 61%, volume loss in 1%, and no effect on adjacent tissue in 37%. NVL associated with epilepsy can be detected with high sensitivity using MR imaging. The temporal lobe location, cortical involvement, and calvarial remodelling are findings typical of NVL. MR characteristics can successfully predict the pathologic substrate of these lesions.

Fast spin echo STIR imaging

OBJECTIVE

Our goal was to evaluate the image quality, contrast characteristics, and possible clinical utility of STIR images obtained using a fast SE (FSE) technique.

MATERIALS AND METHODS

The signal and contrast characteristics of FSE STIR images were evaluated using a lipid/water phantom and normal volunteers. Based upon these results, optimal FSE STIR imaging parameters were chosen. Conventional STIR and FSE STIR images were then obtained (while maintaining an equal number of section locations between the two sequences) in a series of 14 patients with known musculoskeletal abnormalities. These images were compared side by side by two experienced MR radiologists for image quality and lesion detection.

RESULTS

There were no statistically significant differences between the FSE STIR images and conventional STIR images in lesion detection, image quality, motion artifact, or final diagnosis.

CONCLUSION

STIR imaging provides optimal contrast for detection of many pathologic abnormalities. This is especially true for musculoskeletal tumors and infection. The long imaging time and reduced number of sections obtainable with conventional SE (CSE) STIR sequences limit their routine use. Our results show that FSE STIR images of the musculoskeletal system can be obtained up to seven times more rapidly than CSE STIR images without compromising lesion detection or image quality.

Pelvic MR imaging findings in gestational trophoblastic disease, incomplete abortion, and ectopic pregnancy: are they specific?

Thirty-nine patients with abnormally elevated levels of serum beta subunit of human chorionic gonadotropin (beta-hCG) were studied to determine whether findings at magnetic resonance (MR) imaging are specific for primary molar disease, persistent gestational trophoblastic disease (GTD), incomplete abortion, and ectopic pregnancy. Among the latter three groups, the only significant differences were a higher prevalence of endometrial distention in the group with incomplete abortion (P < .0035) and the absence of junctional zone disruption in the group with ectopic pregnancy (P < .05). In the group with primary molar disease, total intrauterine volume was significantly increased (P < .001), and endometrial distention and presence of an endometrial mass had a significantly higher prevalence than that in the persistent GTD groups with (P < .04) or without (P < .001) metastases. Myometrial or extrauterine disease was identified in 65% of the patients with persistent disease and a beta-hCG level greater than 500 mIU/mL (500 IU/L). Thus, although MR imaging findings in persistent GTD, incomplete abortion, and ectopic pregnancy are relatively nonspecific, MR imaging can depict invasive disease that may alter therapeutic management in patients with documented GTD.

Fast spin-echo MR imaging of the female pelvis. Part I. Use of a whole-volume coil

In this prospective study, axial and sagittal magnetic resonance (MR) images were obtained with T2-weighted conventional spin-echo (CSE) and fast spin-echo (FSE) sequences in 34 consecutive female patients who underwent clinical pelvic MR examination at 1.5 T. The MR images from each patient were compared side by side, blindly and independently, by two radiologists experienced in MR imaging who used a standardized score sheet for anatomic and pathologic findings. The FSE sequences were rated superior significantly more often than the CSE sequences in most categories of findings (P less than .05), including overall image quality and reduction of motion artifact. The examination time for the FSE sequences was 1 minute 46 seconds versus an examination time of 9 minutes 14 seconds for the CSE sequences. (Both CSE and FSE sequences provided 18 sections.) It is concluded that the FSE sequence provides T2-weighted anatomic and pathologic information superior to that provided by the CSE sequence and requires substantially less imaging time.

Multicoil high-resolution fast spin-echo MR imaging of the female pelvis

A fast spin-echo pulse sequence was combined with multiple surface coils used simultaneously in the form of a "multicoil" in magnetic resonance imaging studies of the female pelvis. This combination allowed maximal resolution with maintenance of the signal-to-noise ratio (S/N) at an acceptable level, and the S/N with the multicoil system was substantially better than that achieved with a body coil. Excellent image quality and demonstration of anatomic detail were afforded by use of this technique.

Thyroid uptake neck phantoms are not created equal

The main purpose of this communication is to alert nuclear medicine departments to the fact that the earlier version of the water phantom grossly overestimates soft-tissue attenuation in the neck, resulting in calculated thyroid uptake values which are significantly overestimated (in hyperthyroid patients we noted uptake values approaching or exceeding 100%). We believe that the solid Lucite phantom (which is the one recommended by IAEA) better approximates the human neck soft tissue overlying the thyroid. Institutions that continue to use the water phantom should be aware that their thyroid uptakes will be relatively elevated and the normal range must be shifted accordingly. Our normal range is 10%-30% uptake of 123I at 24 hr for the Lucite phantom. For the water phantom, the estimated normal range would be 15%-45%. In addition, the phantom type should be considered when comparing uptake results with those from another institution for a particular patient. Also, treatment doses for Grave's disease could be significantly affected, if such doses are calculated by a formula that depends on uptake.

Chemical shift artifact: dependence on shape and orientation of the lipid-water interface

On magnetic resonance images, chemical shift artifact (CSA) can be seen at a planar lipid-water interface oriented within the plane of the phase-encoding and section-select directions (ie, perpendicular to the frequency-encoding direction). Phantoms and a clinical case were used to demonstrate that when a lipid-water interface is curvilinear (eg, spherical) or planar but not oriented along the section-select direction, CSA may be absent or diminished. This effect can be seen at interfaces of normal structures (kidneys, bladder) as well as at interfaces with pathologic lesions such as lipid-containing dermoids. Not only is this effect dependent on section thickness, field of view, matrix size, and receiver bandwidth, but it is also strongly dependent on the orientation of the interface with respect to the section-select direction. Knowledge of the factors that can alter CSA is important since it is used to distinguish lipid-containing from nonlipid-containing structures of similar signal intensities.

Uterine changes after dilation and curettage: MR imaging findings

To determine what, if any, changes occur in the appearance of the uterus on magnetic resonance (MR) images after dilation and curettage (D&C), nine women without endometrial abnormality underwent imaging before D&C and on day 2 and day 7 after D&C. On day 2, markedly hypointense curvilinear areas in the endometrial canal were noted on MR images in all patients (P = .0002). By day 7, these areas decreased in size in five (62%) and completely resolved in the rest (P = .022). There was no significant change in the width of the endometrial stripe or in the width or signal intensity of the junctional zone or myometrium after D&C. The junctional zone was focally disrupted in one patient who underwent D&C that was complicated by a uterine perforation. Therefore, curvilinear areas of low signal intensity (most likely representing clot) in the endometrial canal were visualized on MR images within 2 days of uncomplicated D&C and decreased in size or resolved over time. Significant widening of the endometrial stripe or disruption of the junctional zone was not observed after uncomplicated D&C.

An evaluation of MRI contrast in the uterus using synthetic imaging

Using a 1.5-T system, we investigated the contrast in MR images of the uterus using a synthetic imaging program that was capable of producing images with TR values of 20 to 10220 ms and TE values of 1 to 511 ms. Synthetic images were calculated from images obtained on six normal women of reproductive age. The synthesized uterine images were essentially indistinguishable from acquired images with the same TR and TE parameters. Cervical and uterine anatomy could be clearly differentiated in synthetic images with a TE = 80 ms when the TR was as low as 100 ms. We conclude that the zonal anatomy of the uterus can be demonstrated using TR values that are much lower than those usually used for demonstrating uterine anatomy.

The role of nifedipine therapy in achalasia: results of a randomized, double-blind, placebo-controlled study

Utilizing the rationale that the calcium channel blocker nifedipine decreases lower esophageal sphincter pressure, we performed a double-blind, placebo-controlled, crossover trial of sublingual nifedipine in achalasia, a disorder whose treatment depends on reduction in lower esophageal sphincter pressure. Ten patients participated in this trial, completed diaries, underwent manometric determinations of lower esophageal sphincter pressure, and had testing of esophageal emptying rates by a solid-meal radionuclide method. Nifedipine, titrated to a dose of 10-30 mg before meals, was well tolerated. Compared with placebo, nifedipine significantly reduced the frequency of dysphagia, but some symptoms of dysphagia, regurgitation, or nocturnal cough were still present most days. Nifedipine significantly reduced lower esophageal sphincter pressure by 28%, a value approximately one-half that achieved by successful pneumatic dilatation or myotomy. Esophageal emptying rates, as determined by the radionuclide method, were unchanged by nifedipine. We concluded that 1) nifedipine reduces symptoms of achalasia, but substantial symptoms do remain during such therapy; 2) the suboptimal effect results from the limited, although statistically significant, effect of nifedipine on reduction of lower esophageal sphincter pressure; and 3) although we believe that nifedipine may be recommended as treatment for achalasia in the subset of patients whose overall medical condition places them at high risk for forceful dilatation or surgery, it cannot be recommended as a standard alternative to these other modalities.

Coil holder and marker system for MR imaging of the total spine

To improve the efficiency of magnetic resonance imaging of the total spine, the authors developed a coil holder and marker system to accurately localize the level of the spine imaged. The patient's external auditory canal and the alignment light on the imager are lined up with marks on the coil holder. The spine is then imaged in three segments by using a 24-cm field of view. The device has been successful in 20 of the 23 patients in whom it was used. The three failures were due to technical problems.

Detection of esophageal motor disorders by radionuclide transit studies. A reappraisal

Radionuclide measurement of esophageal transit has been proposed as a screening test for esophageal motor dysfunction. In this study we evaluated the radionuclide esophageal transit test in 49 consecutive patients undergoing esophageal manometry for esophageal motor disorders. Esophageal transit was assessed using a 10-ml water bolus labeled with 250 microCi technetium-99m sulfur colloid. In preliminary studies in 14 healthy controls, mean transit time was 9.6 +/- 2.1 (SD) sec. Prolonged transit (greater than 15 sec) was observed in two of 28 swallow sequences in the control subjects. Transit times were prolonged in all patients with achalasia or diffuse esophageal spasm, and in five of seven patients with nonspecific abnormalities of peristaltic progression. The test was abnormal in only three of seven patients with high-amplitude peristalsis (nutcracker esophagus) and in none of three patients with hypertensive lower esophageal sphincter. Additionally, prolonged transit was seen in two of 18 patients with normal manometry. We conclude that the radionuclide transit test using a liquid bolus successfully identifies motor disorders characterized by defective peristaltic progression but not disorders in which peristalsis is intact. A major limiting factor appears to be the small number of swallow sequences tested. The test may not, therefore, be accurate enough to consider adopting as a sensitive and noninvasive screening test in the evaluation of patients with suspected esophageal motor disorders.

Identification and mechanism of delayed esophageal acid clearance in subjects with hiatus hernia

To determine if hiatus hernia (HH) contributes to the delayed clearance of acid from the esophagus in patients with gastroesophageal reflux (GER), we performed simultaneous esophageal pH recordings and radionuclide studies in three study populations: 12 GER patients with HH, 5 GER patients with no HH, and 8 subjects with HH but no GER symptoms. Acid clearance was measured at 5 cm. above the manometrically located lower esophageal sphincter (LES) after injecting a 15-ml. bolus of 0.1 N HCl at 15 cm. above the LES. The acid was labeled with 200 mu Ci of 99mTc-sulfur colloid. Acid clearance was also measured at 10 cm. above the LES after injection of a 15-ml. bolus of 0.1 N HCl at 20 cm. above the LES. Acid clearance at 5 cm. above the LES was faster in GER patients with no HH compared to GER patients with HH and asymptomatic HH subjects. Acid clearance was faster at 10 cm. than 5 cm. above the LES in all HH and non-HH subjects studied. In non-HH subjects, each swallow resulted in an increase in pH (a monophasic pH response) at 5 and 10 cm. above the LES. In symptomatic as well as asymptomatic HH subjects, swallows resulted in an initial fall followed by a rise in pH at 5 cm. above the LES (a biphasic pH response). Radionuclide studies showed reflux of the isotope-labeled acid into the esophagus followed by clearance (a biphasic response) accompanying swallows in 15 of the 20 HH subjects. Swallow-induced reflux was not detected by radionuclide scanning in non-HH subjects. Based on these observations, we conclude that during acid clearance a small amount of acid is trapped in the HH sac and refluxes into the esophagus during subsequent swallows when there is relaxation of the LES, and these repeated episodes of acid reflux from the HH account for the delayed acid clearance observed in GER patients with HH.

Effects of morphine and naloxone on esophageal motility and gastric emptying in man

We studied the effect of morphine and naloxone on lower esophageal sphincter pressure, esophageal contraction amplitude, and gastric emptying of solids and liquids in ten normal healthy subjects. Morphine sulfate in a dose of 8 mg intravenous bolus significantly decreased sphincter pressure with a maximum fall of 22.8% of the basal tone. Naloxone, 5 mg intravenous bolus, resulted in a 20% increase in the baseline pressure. There was no change in the esophageal contraction amplitude, duration, or frequency of peristalsis with either morphine or naloxone. Gastric emptying was measured using a dual-isotope technique to simultaneously assess the emptying rates of both solid and liquid meal components. Morphine, 8 mg intravenous bolus, led to a significant inhibition (P less than 0.05) of the gastric emptying of both solids (99mTc sulfur colloid-labeled chicken liver) and liquids (111In DTPA-labeled water). Naloxone, 5 mg intravenous bolus, accelerated the gastric emptying of both solid and liquid components, but this did not achieve statistical significance. These observations suggest that: morphine's inhibitory effect on gastric emptying and lower esophageal sphincter pressure may contribute to its potent emetic properties; the human lower esophageal sphincter and stomach may have opiate receptors and further investigations should be addressed to determining if endogenous opiates play a role in the modulation of sphincter pressure and gastric emptying in humans.

Effect of nifedipine on gastric emptying in normal subjects

We studied the effects of the calcium-channel blocker, nifedipine, on solid and liquid phases of gastric emptying in 10 healthy male volunteers. Each subject underwent a dual-isotope radionuclide gastric emptying determination with and without the preadministration of nifedipine, 30 mg orally, given 20 min prior to ingestion of the test meal over 10 min, following which the subject lay supine under the gamma-counter for 2 hr. Blood samples for measurement of plasma nifedipine concentration were obtained at the time of drug administration and every 30 min throughout the gastric emptying determination. There was a threefold variation in the areas under the plasma nifedipine concentration vs time curve (AUC) obtained in these 10 subjects. Percent gastric retention of either the liquid (water) or the solid (chicken liver) marker was not significantly different after 30 mg oral nifedipine, as compared to the nontreatment day. We concluded that plasma nifedipine concentrations previously reported to be associated with significant esophageal motility effects in humans were not associated with effects on gastric emptying of either liquids or solids.

Vascular thrombosis in acute hepatic allograft rejection: scintigraphic appearance

Hepatobiliary imaging with 99mTc diisopropyl iminodiacetic acid was employed serially in a patient with an hepatic allograft, in order to follow the function of the transplant. Initially improving liver uptake and biliary excretion was observed; however, 12 days postoperative with clinical deterioration the scintigrams revealed an absence of uptake ("phantom" liver), due to thrombosis of the hepatic artery related to acute rejection. Hepatobiliary imaging can be helpful in the study of hepatic allografts.

Delayed hemorrhagic infarction. A cause of late neonatal germinal matrix and intraventricular hemorrhage

Although a single perinatal or postnatal event may be directly correlated to intraventricular hemorrhage (IVH) in some infants, in other infants IVH may be related to a series of insults. Asphyxia, hypotension, and a pressure-passive low cerebral blood flow (CBF) may lead to an infarction. Subsequent events known to cause sudden rises in the CBF may then produce a hemorrhage into damaged tissues. We report two cases of this proposed model for delayed hemorrhage into infarcted tissues, or late IVH. Both neonates were severely asphyxiated, and both experienced profound hypotension and a low CBF on the first postnatal day. Late IVH was found in both neonates; at 2 to 3 months of age, one neonate was found to have computed tomographic evidence for diffuse encephalomalacia, and the other neonate was noted to have an occipital porencephalic cyst.

Intraventricular hemorrhage in the preterm neonate: timing and cerebral blood flow changes

Serial cranial ultrasound studies, 133xenon inhalation cerebral blood flow determinations, and risk factor analyses were performed in 31 preterm neonates. Contrast echocardiographic studies were additionally performed in 16 of these 31 infants. Sixty-one percent were found to have germinal matrix or intraventricular hemorrhage. Seventy-four percent of all hemorrhages were detected by the thirtieth postnatal hour. The patients were divided into three groups: early GMH/IVH by the sixth postnatal hour (eight infants) interval GMH/IVH from 6 hours through 5 days (10), and no GMH/IVH (12). Cerebral blood flow values at 6 postnatal hours were significantly lower for the early GMH/IVH group than for the no GMH/IVH group (P less than 0.01). Progression of GMH/IVH was observed only in those infants with early hemorrhage, and these infants had a significantly higher incidence of neonatal mortality. Ventriculomegaly as determined by ultrasound studies was noted equally in infants with and without GMH/IVH (50%) and was not found to correlate with low cerebral blood flow. The patients with early hemorrhage were distinguishable by their need for more vigorous resuscitation at the time of birth and significantly higher ventilator settings during the first 36 postnatal hours, during which time they also had higher values of PCO2. An equal incidence of patent ductus arteriosus was found across all of the groups. We propose that early GMH/IVH may be related to perinatal events and that the significant decrease in cerebral blood flow found in infants with early GMH/IVH is secondary to the presence of the hemorrhage itself. Progression of early GMH/IVH and new interval GMH/IVH may be related to later neonatal events known to alter cerebral blood flow.

Effect of metoclopramide on normal and delayed gastric emptying in gastroesophageal reflux patients

Gastric emptying has an important role in the pathophysiology of gastroesophageal reflux disease. We investigated the effect of metoclopramide, a gastric prokinetic agent, in gastroesophageal reflux patients with normal as well as delayed emptying. Twenty-six patients with subjective and objective evidence of gastroesophageal reflux ingested an egg salad sandwich meal labeled with 99mtechnetium-DTPA for a baseline study, and then again on a separate day after receiving oral metoclopramide, 10 mg, 30 min prior to the test meal. The mean percent isotope remaining in the stomach after 90 min improved significantly (P less than 0.001) from 70.3 +/- 3.9% (SEM) to 55.2 +/- 4.2% after metoclopramide. Fourteen (54%) had a basal emptying in the normal range of 34-69% retention of isotope at 90 min, (means +/- 2 SD), while it was slow in 12 (46%). For those with delayed basal gastric emptying, the mean retention of 88.9 +/- 2.9% at 90 min was significantly (P less than 0.005) decreased by metoclopramide to 68.6 +/- 6.1%. In those patients with a normal basal gastric emptying and a mean retention of 54.4 +/- 2.3% at 90 min, there was also significant improvement (P less than 0.025) to 43.6 +/- 3.6% after metoclopramide. These data indicate that metoclopramide increased gastric emptying in gastroesophageal reflux patients with normal as well as delayed gastric emptying. Therefore on a patient management level a trial of metoclopramide is warranted in patients with gastroesophageal reflux disease and is not limited by the gastric emptying status of the patient.

Radionuclide esophageal emptying of a solid meal to quantitate results of therapy in achalasia

In this study we evaluated esophageal emptying using an isotope-labeled solid meal (an egg salad sandwich labeled with 99mTc-sulfur colloid) and compared it with lower esophageal sphincter pressure and a graded symptom score in the assessment of treatment in achalasia. Twenty-nine achalasic patients had lower esophageal sphincter pressure and esophageal emptying measured before treatment. Emptying at 5 min in the achalasic patients was significantly delayed, compared with normals (p less than 0.001), but did not correlate with resting lower esophageal sphincter pressure. After treatment lower esophageal sphincter pressure fell by 63% (p less than 0.01). A similar improvement was observed in esophageal emptying at 5 min after both pneumatic dilatation (63%, p less than 0.01) and surgery (70%, p less than 0.05). Percentage change in lower esophageal sphincter pressure and percentage change in esophageal emptying were significantly correlated (r = 0.76, p less than 0.01). There was also a significant correlation between symptom score and percentage change in both esophageal emptying (r = 0.70, p less than 0.05) and LES pressure (r = 0.77, p less than 0.05). Radionuclide measurement of esophageal emptying using a solid meal is a simple, noninvasive, and physiologic test of esophageal function. In achalasia, changes in emptying after treatment generally reflect the patient's clinical status and correlate with changes in lower esophageal sphincter pressure. The results suggest that radionuclide esophageal emptying of a solid meal may be a practical alternative to esophageal manometry in the assessment of treatment and may have an important future role as an objective parameter in comparing new treatment modalities.

Postpartum perfusion of the preterm brain: relationship to neurodevelopmental outcome

Bayley developmental assessments were performed at 12 months corrected age on 11 preterm infants, all of whom had undergone 133-Xenon cerebral blood flow measurements (CBF) on the 1st day of life and neonatal computerized tomography scans for the detection of intraventricular hemorrhage. The Bayley mental index was found to vary as a quadratic function of CBF to the left hemisphere, with moderate CBF values associated with more favorable outcomes than either low or high CBF values.

Gold- 195m, a new generator-produced short-lived radionuclide for sequential assessment of ventricular performance by first pass radionuclide angiocardiography

The feasibility of performing rapid sequential first pass radionuclide angiocardiography using a new short-lived radiotracer, gold-195m (195mAu) half-life 30.5 seconds) was evaluated. This radionuclide emits a 262 keV gamma ray and is the daughter of mercury-195 (195mHg) (half-life 41.6 hours). The prototype tabletop 195mHg/195mAu generator produced 20 to 25 mCi of 195mAu in 2 ml of eluate (yield of 40 percent). The breakthrough of 195mHg in the eluate was 0.02 percent of the amount of 195mHg in the generator. The eluate contained 20 microCi of 195mHg per study, resulting in an estimated human radiation dose of 0.007 rad/study to the whole body and 0.34 rad/study to the kidney. Four dogs each had 15 to 20 sequential first pass studies performed with 195mHg at 3 to 10 minute intervals using a computerized multicrystal gamma camera. During the left ventricular phase, 160,000 to 190,000 counts/s were acquired. The end-diastolic left ventricular region of interest contained 3,000 to 6,000 counts (background- and decay-corrected). Multiple reproducible values for left ventricular ejection fraction were obtained during stable conditions. The mean (+/- standard deviation) interstudy variability was 4 +/- 2 percent. During infusion of isoproterenol, rapid increase of left ventricular ejection fraction was demonstrated. Excellent agreement was observed between studies performed with technetium-99m diethylenetriaminepentaacetic acid (99mTc-DTPA) and 195mAu. The mean interstudy difference was 4 +/- 3 percent. Thus, sufficiently high yield and dose are obtained from the 195mHg/195mAu generator for reliable high count rate first pass determination of left ventricular ejection fraction. This new short-lived radiotracer makes possible rapid sequential assessments of ventricular function at greatly reduced patient exposure to radiation.

Alterations in cerebral blood flow in preterm infants with intraventricular hemorrhage

Xenon-133 inhalation hemispheric cerebral blood flow (HCBF) determinations at one to two days and four to six days postnatally and at 37 weeks postconceptual age have been correlated with computed tomography (CT) scan and autopsy findings in 15 preterm infants weighing less than 1,250 gm at birth. Ten of these infants had germinal matrix hemorrhages (GMH) or intraventricular hemorrhages (IVH). Although HCBF obtained at one to two days showed no mean difference between the GMH/IVH group and the nonhemorrhage infants, hemispheric flow ratios showed significant discrepancies in the GMH/IVH group. In addition, in four of five patients in whom the hemorrhage appeared asymmetric on CT scan, the side of higher flow correlated with the hemorrhage. At four to six days HCBF showed a lower mean value in the GMH/IVH patients than in the nonhemorrhage patients and differences in the interhemispheric ratios in the GMH/IVH group persisted. There were no differences in the mean HCBF values or hemispheric ratios between the two groups of infants at 37 weeks postconceptual age.

Abdominal and hepatic uptake of 99mTc-pyrophosphate in neonatal necrotizing enterocolitis

Abdominal 99mTc-pyrophosphate (99mTc-PYP) scans were obtained in 15 neonates: 12 with neonatal necrotizing enterocolitis (NEC), two with osteomyelitis, and one with myocarditis. Ten of the babies with NEC had at least one positive scan; of these 10 studies, seven (Group A) showed both diffuse abdominal uptake and localized hepatic activity, two (Group B) showed abdominal uptake and questionable hepatic uptake, and one (Group C) demonstrated diffuse abdominal uptake only. The other two babies with NEC had normal scans (Group D). Pneumatosis intestinalis was unquestionably present in two patients from Group A and one from Group B. Upon resolution of the clinical findings, all NEC patients had normal scans. A patient with myocarditis had hepatic uptake of 99mTC-PYP while the abdominal scan in the two infants with osteomyelitis was normal. These preliminary observations suggest that further study of a relationship between abdominal scan findings and the course of NEC is warranted.