Intraoperative monitoring and postoperative imaging of hepatic cryosurgery

Because intraoperative sonography displays segmental anatomy, allows discovery of more lesions than previously suspected from preoperative imaging, surgical inspection, or palpation, and permits more certain diagnosis of problematic masses, it facilitates surgical decision-making when liver resection or cryoablation is anticipated. Intraoperative sonography provides a guidance modality to accurately place cryosurgery probes in liver masses. More precise treatment of metastatic and primary tumors of the liver is possible with cryoablation because intraoperative sonography provides a means of monitoring the growth of the enlarging freeze zone to insure adequate surgical margins. Postoperative detection of acute complications after cryosurgery is best done with computed tomography. Normally cryosurgery defects shrink with time and lose the peripheral contrast opacification seen after surgery. Gas collections, seen as a result of tissue necrosis, must be discriminated from infection. Tumor recurrence can be detected well with computed tomography or magnetic resonance imaging following hepatic cryosurgery.

A multicenter, placebo-controlled, randomized, double-blind, prospective trial of prophylactic ursodiol for the prevention of gallstone formation following gastric-bypass-induced rapid weight loss

BACKGROUND

Previous studies have documented a high incidence of gallstone formation following gastric-bypass (GBP)-induced rapid weight loss in morbidly obese patients. This study was designed to determine if a 6-month regimen of prophylactic ursodiol might prevent the development of gallstones.

METHODS

A multicenter, randomized, double-blind, prospective trial evaluated 3 oral doses of ursodiol: 300, 600, and 1,200 mg versus placebo beginning within 10 days after surgery and continuing for 6 months or until gallstone development, for patients with a body mass index (BMI) > or = 40 kg/m2. All patients had normal intraoperative gallbladder sonography. Transabdominal sonography was obtained at 2, 4, and 6 months following surgery, or until gallstone formation.

RESULTS

Of 233 patients with at least one postoperative sonogram, 56 were randomized to placebo, 53 to 300 mg ursodiol, 61 to 600 mg ursodiol, and 63 to 1,200 mg ursodiol. Preoperative age, sex, race, weight, BMI, and postoperative weight loss were not significantly different between groups. Gallstone formation occurred at 6 months in 32%, 13%, 2%, and 6% of the patients on the respective doses. Gallstones were significantly (P < 0.001) less frequent with ursodiol 600 and 1,200 mg than with placebo.

CONCLUSION

A daily dose of 600 mg ursodiol is effective prophylaxis for gallstone formation following GBP-induced rapid weight loss.

Angle independent Doppler color imaging: determination of accuracy and a method of display

A multiple beam technique was utilized to obtain angle independent Doppler color images (AIDCI) using an ultrasonic scanner with a linear transducer. A quantitative study using steady flow models has been performed to evaluate the accuracy of this method in velocity measurements. The results show that the velocity amplitudes measured with this method correlated with those calculated from the measured flow rates (r = 0.95-0.98). The flow angles obtained with this method also correlated with those calculated from the coordinates of the tube image (r = 0.93-0.96). To improve the interpretation of the angle independent results, a method for visualizing two-dimensional flow fields is presented and compared with two existing methods.

Gallstones in patients with morbid obesity. Relationship to body weight, weight loss and gallbladder bile cholesterol solubility

Gallstones are common in obesity, and in individuals undergoing weight reduction. However, the relationships between body weight, weight reduction, gallbladder bile composition and gallstone formation are not well understood. The present studies were conducted on a cohort of 230 morbidly obese individuals presenting for bariatric surgery. Mean body weight ranged from 90-235.4 kg (mean: 136.2 kg). Body mass index (BMI) ranged from 35.4-94.7 kg/m2. Thirty-two patients (14%) had undergone prior cholecystectomy and 48 (21%) were found to have gallstones by intraoperative ultrasonography. No significant relationship was observed between gallstone prevalence and body weight. Following bariatric surgery weight loss averaged 1.57 kg/week over six months. Absolute weight loss ranged from 13.6-81.3 kg. Symptomatic gallstones requiring cholecystectomy developed in 15/150 patients (10%) over two years of follow-up. In contrast, ultrasonography detected asymptomatic gallstones in 34/92 patients (37%) six months following bariatric surgery. No relationship existed between the amount of weight lost and gallstone formation. Gallbladder bile cholesterol solubility remained constant throughout the entire weight range present in this population. No significant difference in cholesterol solubility was present between persons presenting for bariatric surgery and patients who developed symptomatic gallstones and underwent cholecystectomy following weight reduction. We conclude that gallstones are common in patients with severe obesity both before and following bariatric surgery. However, weight loss per se does not appear to be the major determinant of gallstone formation in persons who weigh in excess of 100 kg.

Occult breast masses: use of a mammographic localizing grid for US evaluation

To determine if there was a problem of misidentification of mammographically detected masses with freehand ultrasound (US), the authors examined 50 mammographically distinct masses in 47 patients who were scheduled to undergo needle localization. In only six cases were the masses to be localized in an area of the breast that contained other mammographic opacities that could have led to problems of identification. The patients were first studied with freehand US. Results were then compared with those subsequently obtained with a fenestrated mammographic compression grid to guide the US evaluation. Needle localization was then performed. In five of 50 cases, masses detected with freehand US and initially believed to correspond to the mammographically detected mass were subsequently found to represent different areas of the breast when US was used with the compression grid. These results suggest that the potential for misidentification of masses with freehand US is real and that a mammographic grid localization device can be used to overcome this problem.

Gallstone formation after rapid weight loss: a prospective study in patients undergoing gastric bypass surgery for treatment of morbid obesity

The present study evaluated the incidence of gallstone formation in 105 morbidly obese patients undergoing rapid weight loss after proximal gastric bypass surgery. Intraoperative ultrasonography demonstrated gallstones in 20 (19%) and gallbladder sludge in four (4%) patients. Eighty-one patients had a normal gallbladder ultrasound. After bariatric surgery, these patients were followed prospectively with periodic gallbladder ultrasound examinations. At 6 months, gallstones had developed in 36% and gallbladder sludge in 13% of patients. These percentages remained relatively constant at 12 and 18 months. Body weight declined rapidly after surgery from a mean of 132.3 kg to 95.5, 87.0, and 84.0 kg at 6, 12, and 18 months, respectively. Gallstones developed significantly more often in the white race, and in women. No significant differences in age, body weight, percent ideal body weight, percent weight loss, or percent of excess body weight lost existed between patients who developed gallstones or sludge and those who did not. Patients who developed gallbladder sludge had less cholesterol and lower cholesterol saturation (1.25 +/- 0.42) in their gallbladder bile than persons who developed gallstones (2.00 +/- 0.79). Forty percent (13/32) of patients who developed gallstones became symptomatic; nine (28%) underwent elective cholecystectomy. An attempt to prevent gallstone formation during rapid weight loss appears warranted.

Use of intraoperative ultrasound during hepatic resection in pediatric patients

Five pediatric patients with primary liver tumors were evaluated preoperatively with ultrasound (US), computerized tomography (CT), and angiography, and tentative operative plans were formulated. Intraoperative US was subsequently used to examine these children, resulting in changes in operative strategy of all five patients despite their extensive preoperative evaluations. Intraoperative ultrasound appears to provide the most accurate assessment of both the extent of tumor and its vascular relationships. Thus, operative strategies may be precisely tailored on the basis of such information, allowing rational resection where appropriate, while futile attempts at removal of inoperable lesions may be averted.

Inflammatory aneurysm of the abdominal aorta: diagnosis by computerized tomography and ultrasonography

We correctly diagnosed seven cases of inflammatory aneurysm of the abdominal aorta preoperatively by computerized tomography (CT) and ultrasonography (US). Excessive thickening of the aneurysmal wall and conspicuous enhancement on CT are the characteristic features that led to the correct diagnosis. Ultrasonographic findings are nonspecific, but US is the screening method of choice. If US shows a sonolucent zone anterior or anterolateral to an atherosclerotic aneurysm, CT should be used to delineate the perivascular abnormalities.

Upper abdominal trauma: pitfalls in CT diagnosis

Medical records and computed tomographic (CT) scans of 83 patients with upper abdominal trauma were retrospectively reviewed to determine errors in diagnosis using CT. Patients with possible pancreatic injury, small bowel perforation, or injury to an occult malignancy represented the most difficult diagnostic cases. A false-positive diagnosis of pancreatic injury occurred in seven of 77 patients (9%) and represented the most frequent error in the series. In three patients with subsequently surgically proved small bowel perforation, one duodenal and two proximal jejunal, the injuries were not correctly diagnosed on CT scans. In retrospect, positive CT findings were present in the case of duodenal rupture. Additionally, in two patients, duodenal rupture was suspected based on CT findings of extraluminal gas and fluid near the duodenum, but both cases were proved normal at surgery. The series included three patients with trauma involving unsuspected tumors in the liver, kidney, and stomach.

Regenerating nodules in cirrhosis: sonographic appearance with anatomic correlation

A sonographic-anatomic correlation study was undertaken to define the sonographic appearance of regenerating nodules in cirrhotic livers. Three cirrhotic livers with multiple regenerating nodules were obtained from patients undergoing liver transplantation. Sonograms of the resected livers were made and correlated directly with the anatomic specimens. Using a 3-MHz transducer, no discrete alterations in the echo texture of the livers were seen to correspond to the regenerating nodules. With a 7.5-MHz transducer, discrete islands of liver parenchyma were identified corresponding to regenerating nodules anatomically. The nodules were recognized because of visualization of thin, slightly more echogenic borders, which corresponded pathologically to fibrous and fatty connective tissue surrounding and separating the nodules.

Extratesticular hemorrhage associated with torsion of the spermatic cord: sonographic demonstration

Using ultrasound (US), we studied seven patients with torsion of the spermatic cord associated with a large amount of extratesticular hemorrhage. In each case, US showed a large echogenic or complex extratesticular mass caused by the hemorrhage, in addition to a hypoechoic testis and scrotal skin thickening. This appearance should be recognized as part of the spectrum of sonographic appearances that can be seen in torsion.

Focal fat necrosis presenting as a palpable abdominal mass: CT evaluation

We report an unusual case in which the coalescence of fat necrosis foci produced a palpable abdominal mass. Hence, focal fat necrosis should be included in the differential diagnosis of abdominal masses in patients with a history of pancreatitis.

Sonography of emphysematous pyelonephritis

Emphysematous pyelonephritis is a rare gas-producing bacterial infection of the renal parenchyma seen primarily in patients with diabetes mellitus. Sonographic findings in four patients with this disease are described. Sonographic features consist of multiple high-amplitude echoes within the renal parenchyma, renal sinus, and/or perirenal space accompanied by acoustic shadowing. Computed tomography confirmed bilateral involvement in one case. Plain abdominal radiographs demonstrated abnormal extraluminal gas in three of four cases. The role of sonography in diagnosis is discussed.

CT of the normal and abnormal parametria in cervical cancer

To evaluate CT criteria for differentiating a cervical cancer confined to the cervix from a lesion that invades the parametria, 16 patients with newly diagnosed, untreated cervical cancer were studied with CT. Twenty-five parametria were confirmed by radical hysterectomy, transvaginal parametrial fine-needle aspiration cytology, or excretory urography. In eight tumor-free parametria, CT findings indicating confined tumor were: (1) smooth, well defined cervical margins; (2) lack of prominent parametrial soft-tissue strands; (3) no parametrial soft-tissue mass; and (4) preservation of the periureteral fat plane. The simultaneous occurrence of these four findings was seen in six of eight tumor-free parametria and in no tumor-infiltrated parametria. In 17 tumor-positive parametria, CT findings associated with parametrial tumor invasion were: (1) irregularity or poor definition of the lateral cervical margins; (2) prominent parametrial soft-tissue strands; (3) obliteration of the periureteral fat plane; and (4) an eccentric parametrial soft-tissue mass. The latter two findings were seen only in tumor-positive parametria. Irregularity of the cervical margins and prominent parametrial strands were seen most commonly with parametrial tumor invasion, but were also occasionally seen with parametrial inflammation. On the basis of the criteria developed in this report, CT may be used as an adjunct to the physical examination in differentiating stage I cervical cancer from more advanced disease in selected patients.

Traumatic renal artery occlusion: CT diagnosis with angiographic correlation

Traumatic renal artery occlusion is a rare injury and may be clinically silent or vague in its presentation. In the appropriate clinical setting CT findings are diagnostic, enabling prompt arteriographic evaluation and early surgical intervention.

Ascites: comparison of plain film radiographs with ultrasonograms

Plain film abdominal radiographs of 100 cases of ultrasound-proved ascites were reviewed for findings of ascites. In addition, 100 nonascitic cases proved by sonography were reviewed to evaluate the specificity of these findings. We found that all the described plain film radiographic signs of ascites except the hepatic angle sign are insensitive though specific. The hepatic angle sign has a sensitivity of 84% and a specificity of 70%.

Traumatic rupture of the diaphragm: real-time sonographic diagnosis

Traumatic rupture of the diaphragm may be caused by either penetrating or blunt trauma. The diagnosis is often delayed because of attention to other serious injuries or lack of specific clinical and radiographic signs. In cases of penetrating peridiaphragmatic trauma, the possibility of a diaphragmatic laceration may not be considered, or the plain film findings may be extremely subtle or absent [1]. We report a case of delayed presentation of traumatic diaphragmatic hernia demonstrated by real-time sonography [2]. To our knowledge, this is the first reported case in which sonography provided a definitive diagnosis and prompted immediate surgical repair.

Impact of sonography on surgery for primary hyperparathyroidism

The impact of preoperative sonographic localization of enlarged parathyroid glands was evaluated from the standpoint of operative time and complication rates. There was a reduction in the average time from 135 minutes when findings were false-negative to 111 minutes when findings were positive. The rate of complication was not changed by accurate preoperative localization. When the operative goal is to find all parathyroid glands in every patient, the value of preoperative localization of parathyroid tumors by any current method is slight. Should operative policy favor a search for only one enlarged and one normal gland, or should methods improve to the point that even normal parathyroid glands can be located reliably, noninvasive localization should prove to be useful, safe, and cost-effective, even when it is carried out before initial operation.

Renal biopsies under ultrasound guidance: 100 consecutive biopsies in children

To examine the number of renal biopsies in correlation with the pattern of referrals as well as the major categories of renal diseases for the procedure peculiar to children, the data of 100 consecutive percutaneous renal biopsies using disposable biopsy needles under ultrasound guidance in 99 children were reviewed. To examine the risks and accuracy of the procedure the estimated depth of the kidney by ultrasound, the actual biopsy depth, the success rate and the complications were evaluated. With rare exception, 1 core of renal tissue was obtained per single needle insertion; 109 needle insertions yielded 103 cores. Of the specimens 92 per cent contained more than 10 glomeruli. Gross hematuria with the first voiding post-biopsy occurred in 12 per cent of the cases but persisted beyond 24 hours in only 1 per cent. No long-term complications were observed. Percutaneous renal biopsy with the disposable needle guided by ultrasound represents a considerable advance in diagnostic technique and deserves wider application in the evaluation and management of a number of pediatric kidney disorders.

Midline cerebral arterio-venous anomalies: ultrasound diagnosis

Ultrasound features of three cases of midline cerebral arterio-venous anomalies of neonates presenting with congestive heart failure are presented. Two cases have CT and angiographic correlation. The third case has post-mortem correlation. Ultrasound easily detected the dilated midline vascular channels in all three cases. Angiography was needed to further define the abnormal anatomy. We suggest a role for ultrasound to screen for midline arteriovenous malformations in neonates with congestive heart failure of undetermined etiology.