Monzer M. Abu-Yousef

Tentative diagnoses facilitate the detection of diverse lesions in chest radiographs.

The influence of clinical history upon detection has been frequently studied. In a unique investigation, detection of diverse abnormalities commonly encountered in practice was tested, and the influence of clinical history was conceptualized as suggesting a tentative diagnosis. Categorical prompts that were correct for specific abnormalities resulted in detection superior to that with unprompted reading. Prompts that were plausible but incorrect for abnormal and normal cases led to very few false-positive responses, and subsequent reports of specific abnormalities were as accurate as in unprompted reading. It is concluded that appropriate clinical history results in improved perceptual performance rather than simply improved decision-making.

Doppler US of the Liver Made Simple

Doppler ultrasonography (US) is usually the first-line modality for evaluating flow in native liver vessels and transjugular intrahepatic portosystemic shunts (TIPS). Waveforms, which represent flow in each of the major vessels and in TIPS, have been well described. The appearance of these waveforms should be recognized, and the mechanisms behind their generation should be understood by those interpreting these examinations. Understanding how waveforms are formed--that is, their mechanisms for generation--is predicated on knowing basic vascular Doppler concepts and established nomenclature. This article is a review of these basic concepts and nomenclature as applied to the interpretation of liver Doppler US waveforms.

Sonography of acute appendicitis in pregnancy

Background:Clinical evaluation of acute appendicitis is difficult in pregnant patients. Delay in diagnosis is associated with increased fetal mortality. The purpose of our study was to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women.Methods:We obtained sonograms in 22 pregnant women suspected of acute appendicitis. All sonograms were performed using graded-compression to detect an enlarged appendix. The sonographic criteria for acute appendicitis were detection of a noncompressible blindended and tubular multilayered structure of maximal diameter greater than 6 mm.Results:The sonographic findings were correlated with surgical findings in seven cases and clinical follow-up in 15 cases. Acute appendicitis was diagnosed by sonography in three of 22 patients, and in all but one was confirmed by surgical and pathologic findings. In the remaining 19 patients, 15 improved on clinical follow-up; three were shown to have a normal appendix at surgery and one had focal acute inflammation at the tip of the appendix.Conclusions:Our experience suggests that graded-compression sonography is a useful procedure in pregnant patients suspected of acute appendicitis and has a similar accuracy as in nonpregnant women, especially in the first and second trimester.

Strenuous exercise decreases motility and cross-sectional area of human gastric antrum. A study using ultrasound.

Gastric emptying in humans is delayed with strenuous exercise. We used ultrasound imaging in six healthy volunteers to determine whether changes in motility and configuration of the gastric outlet contribute to this delay. After fasting, all individuals ingested chicken broth and garbanzo beans. With subjects sitting upright, transverse and longitudinal real-time views of the gastric antrum were recorded on video tape. In the exercise studies, subjects pedaled an ergometer for 10 min to attain a heart rate of 85% predicted maximum. On a different day, all subjects had an identical study without exercise. The order of performance of exercise and no-exercise studies was randomized. After exercise, contraction frequencies and antral areas were significantly reduced compared to the studies without exercise. In addition, after exercise there was closure of the pylorus and tubular narrowing of the gastric antrum. Closure of the pylorus and decreased gastric antral area and motility may be important in explaining the decrease in gastric emptying that occurs with strenuous exercise.

Magnetic Resonance Imaging of Anomalous Fetuses

&NA; 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. (Obstet Gynecol 73:952, 1989)

Management and outcome of pineal region tumors.

The management and outcome of 45 patients with tumors in the pineal region are reviewed. The overall male to female ratio was 2:1, and over one-half of the patients presented during the 2nd decade of life. Sixteen of the 21 survivors are presently gainfully employed and suffer only minor deficits. Two of 3 survivors in whom the lesion was biopsied harbored germinomas, while the third had an epidermoid. Among the 18 nonsurvivors, all of whom died of their tumors, 15 succumbed within 2 1/2 years of hospital admission. Twelve of the 13 nonsurvivors in whom histological confirmation was obtained by operation or autopsy had malignant tumors. Computed axial tomography was helpful in making the diagnosis of tumor type in 7 of the 11 cases with confirmed pathology. Cerebrospinal fluid cytology disclosed malignant cells in 4 of 11 patients with proven pineal malignancy. Irradiation and shunting were performed in nearly all survivors and in a little over one-half of the nonsurvivors. Where noninvasive studies are equivocal for malignancy, biopsy may be indicated.

Preoperative sonographic diagnosis of gallbladder torsion : report of two cases

Acute torsion of the gallbladder is increasingly seen in clinical practice in the elderly population. Delay in surgical treatment may be fatal. In this report, we describe two cases of torsion of the gallbladder in elderly women, in which sonographic diagnosis was made preoperatively, leading to prompt surgical intervention. In both cases the clinical findings were nonspecific. We also describe the color Doppler findings in one case. Preoperative diagnosis of this condition was suggested in an earlier report. l

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.

Diagnosis of acute appendicitis on transvaginal ultrasonography.

Appendicitis is the most common acute abdominal condition requiring surgery in the western world.1 The combination of signs, symptoms, and laboratory values may, however, be equivocal in approximately one-third of patients with acute appendicitis.1 Diagnosis is particularly difficult in young women of childbearing age in whom acute gynecologic problems can be confused with acute appendicitis. In such patients, an increased rate of normal appendices are found more frequently at surgery (35 to 40%).2.3 Using transabdominal ultrasonography in patients with clinical suspicion of appendicitis, an accurate diagnosis of appendicitis can be made in approximately 52% of young women, and an alternative diagnosis can be made in 33%.4 Many advocate graded compression sonography of the right lower quadrant to evaluate for appendicitis, combined with transvaginal ultrasonography of the pelvis for evaluation of acute gynecologic pathologic processes. We endorse this view but present the two cases in whom the diagnosis of acute appendicitis was made at the transvaginal examination.

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.