Magnetic resonance imaging of anomalous fetuses

Magnetic resonance imaging (MRI) has been used sparingly in obstetrics. The reasons for this relate mainly to cost, availability, difficulty obtaining clear images because of fetal movement, and the convenience and utility of ultrasound. However, MRI use is expanding and has the potential to play an important role in selected problem pregnancies. We studied the pregnancies of five women whose fetuses showed anomalies by ultrasound. These included cases of a large body wall defect, a diaphragmatic hernia, hydrocephalus, Meckel-Gruber syndrome, and iniencephaly with a diaphragmatic hernia (the iniencephaly sequence). Three of these examinations followed fetal neuromuscular blockade, and two were associated with oligohydramnios without fetal paralysis. Paralysis provided superior images. The fetal central nervous system, subcutaneous tissue, and liver imaged particularly well. This study illustrates that MRI can enhance and even clarify certain information provided by ultrasound.     

Improved US visualization of the pancreatic tail with simethicone, water, and patient rotation

PURPOSE: To evaluate the effect of degassed water, simethicone, and patient rotation on ultrasonographic (US) visualization of the pancreatic tail. MATERIALS AND METHODS: Seventy patients in whom visualization of the pancreatic tail was poor at US were reevaluated in the upright position after ingesting 2 cups (500 mL) of water with 80 mg of simethicone followed by rotating three times on the examination table. In a few patients, the right posterior oblique position was used. Pancreatic tail visualization and disbursement of gastric gas were evaluated. Seventy patients who received 500 mL of distilled water only served as control subjects. RESULTS: Pancreatic tail visualization in patients versus control subjects was complete in 55 (79%) versus five (7%) of 70 patients and control subjects, partial in 10 (14%) versus 38 (54%), and not improved in five (7%) versus 27 (39%). The effect on diminishing gastric air was closely correlated with the degree of improved visualization in most patients. All patients tolerated the procedure well, with no side effects. The technique added a mean of 8 versus 5 minutes to the examination in patients versus control subjects. The full acoustic window effect of the simethicone-water mixture lasted approximately 10 minutes. CONCLUSION: The simethicone-water-rotation technique is simple, safe, inexpensive, and effective for improving pancreatic tail visualization in ambulatory patients and is superior to the use of water alone.     

Catheter-induced cystitis: evaluation by cystosonography

The bladders of 23 patients with indwelling catheters were examined by ultrasound and cystoscopy. Twelve of the 23 showed changes consistent with bullous cystitis, a catheter-induced reaction of the bladder mucosa that may simulate a bladder tumor on intravenous urography and sonography. The changes seen included a thickened mucosa that was smooth in the early stages, becoming redundant and polypoid in later stages. The mucosa was usually hypoechoic and the lesions were localized on the posterior wall or were diffuse and more severe, depending on the length of catheterization. It is concluded that the sonographic findings in the appropriate clinical setting are suggestive of this entity. Although cystoscopy is not often indicated, cystoscopic findings are diagnostic and biopsy is, therefore, unnecessary.     

Prostatic carcinoma: detection and staging using suprapubic US

Eighteen patients with pathologically proved carcinoma of the prostate were examined with suprapubic ultrasound (US) to assess the capability of the modality in the detection and staging of the disease. Five of the patients were evaluated for recurrent disease. A detailed, retrospective, echo-textural analysis of the prostate and periprostatic structures was performed. The most frequently encountered US findings were recorded and used as criteria in the diagnosis and staging. Most diagnostic of the echo patterns were the presence of a large (greater than 6 mm) focal density within the peripheral zone that was as bright as or less bright than the density of the capsule, a mixed or diffuse pattern, and loss of integrity of the capsule, seminal vesicles, or bladder. Using these criteria, we were able to correctly diagnose 17 of 18 cases, with an accuracy rate of 94%. US was also used to assess the extent of local disease in carcinoma of the prostate. The US staging was compared with the staging by digital rectal examination and by clinicopathologic results. We correctly staged 15 of 18 cases (83%) with US, while the rectal examination helped to stage correctly only 10 of 18 cases (56%). All errors were due to understaging. We find suprapubic US to be very helpful in the diagnosis and staging of prostatic cancer. Since there is some overlap between the findings in benign and malignant disease, we cannot recommend US as an alternative to prostate biopsy. Further experience in detection and staging with prospective studies may be necessary before final conclusions can be made.     

Diagnostic value of gadolinium-enhanced 3D magnetic resonance angiography in patients with suspected hepatic arterial complications after liver transplantation

PURPOSE: To evaluate the accuracy and clinical role of gadolinium-enhanced 3D magnetic resonance angiography (MRA) in patients with suspected hepatic arterial complications after liver transplantation. MATERIALS AND METHODS: Thirty-six consecutive MRA studies were performed in 33 liver transplant recipients after transplantation. MRA image quality was assessed subjectively. Thirty-two MRA studies were retrospectively reviewed and correlated with surgery (n = 2), conventional angiography (n = 18), or clinical follow-up (n = 12). MRA findings were also correlated with those of Doppler sonography in 30 of the cases. In 20 cases, concordance between MRA and surgery or conventional angiography was evaluated for each grade of hepatic artery stenosis (normal, mild [<50%], moderate [50-75%], severe [>75%], or occluded). RESULTS: MRA image quality was degraded 13 of 36 cases (36.1%) studies. The sensitivity, specificity, and accuracy of MRA by consensus reading for more than 50% of hepatic artery stenosis or occlusion were 67%, 90%, and 81.3%, respectively. Of the 19 cases in which Doppler sonography was abnormal, MRA correctly characterized hepatic artery stenosis in 16 (84.2%). MRA also correctly identified all 5 occurrences of celiac artery stenosis. However, MRA overestimated the severity of hepatic arterial stenosis in 3 (15%) of 20 cases and underestimated 5 (25%) of 20 cases. CONCLUSION: MRA complements Doppler ultrasound to exclude significant hepatic artery stenosis. However, a substantial number of MRA studies were technically inadequate, and MRA demonstrated limited efficacy for correctly grading the severity of hepatic artery stenosis.     

Subchorionic hemorrhage: sonographic diagnosis and clinical significance

Twenty-one pregnancies with sonographic evidence of subchorionic hemorrhage were evaluated clinically and sonographically. Clinical evaluation included maternal age, gravidity, parity, gestational age, presence of pain, presence and amount of bleeding, and pregnancy outcome. Sonographic evaluation included the relative and absolute size of the hematoma, its echogenicity and location in relation to the placenta, the presence of marginal placental abruption, and progress on follow-up examinations. The outcome of these pregnancies was unfavorable in 15 cases (71%) and correlated well with the relative and absolute size of the hematoma, severity of vaginal bleeding, change in hematoma size on follow-up examination, and presence of pain. There was no significant correlation between the outcome and the echogenicity of the hematoma, presence of placental margin elevation, gestational and maternal age, gravidity, or parity. All hematomas extended to the margin of the placenta. Subchorionic hemorrhage is a frequent cause of first and second trimester bleeding and has a grave prognosis. Familiarity with the varied sonographic appearances and meticulous sonographic examination with special attention to the placental margins can be helpful in the diagnosis.     

Enlargement and hypervascularity of both the epididymis and testis do not exclude involvement with lymphoma or leukemia

We present 3 cases of diffuse infiltration of the testes and epididymides by malignant lymphoma and leukemia. Gray-scale and color Doppler sonograms showed diffuse hypoechoic enlargement and hypervascularity of the involved testes and epididymides. The authors emphasize that enlargement and hypervascularity of both the epididymis and testis can be caused by lymphomatous/leukemic involvement and is not always indicative of epididymo-orchitis.     

Pulsatile lower limb venous Doppler flow: prevalence and value in cardiac disease diagnosis.

The purpose of this study was to assess the frequency and significance of pulsatile Doppler waveforms in lower limb veins. We used Doppler sonographic data from the common femoral vein. In the first of two groups, the findings in 250 patients were correlated with the presence of cardiac decompensation on concurrent chest radiographs. In the second group, the findings in 81 patients were correlated with the presence of tricuspid regurgitation on Doppler echocardiograms. A venous Doppler sonographic examination was considered normal if spontaneous anterograde phasic flow was present and pulsatile if flow had a cyclic retrograde component. In group 1, 21% had pulsatile waveforms whereas 24% had cardiac decompensation. In group 2, 36% had pulsatile waveforms and 43% had tricuspid regurgitation. A statistically significant correlation was found between the presence of these abnormal waveforms and cardiac decompensation or tricuspid regurgitation, with sensitivities of 57% and 54%, specificities of 91% and 78%, positive predictive values of 66% and 66%, negative predictive values of 87% and 69%, and accuracies of 82% and 68%, respectively. In a subgroup of 55 patients who had both tests for correlation and in whom both were in agreement, the sensitivity of venous Doppler sonographic examination for detecting pathologic cardiac conditions was 79%, specificity was 87%, positive predictive value was 83%, negative predictive value was 84%, and accuracy was 84%. In 77 patients with pulsatile waveforms, including 24 without concurrent chest radiographs or echocardiograms, 63 (82%) had no prior history of cardiac disease. When correlated separately with chest radiograph or Doppler echocardiography, the test is not very sensitive in the diagnosis of cardiac disease; however, when both correlating tests are performed and are in agreement, all diagnostic parameters of the venous Doppler sonographic test, including sensitivity, become fairly high. The presence of pulsatile lower limb venous Doppler flow should alert the sonologist that a pathologic cardiac condition may be the culprit, especially in patients who have no such prior diagnosis.