Acute appendicitis: high-resolution real-time US findings

High-resolution, real-time ultrasonography (US) with graded compression was used to evaluate 90 patients with clinically suspected acute appendicitis. US visualization of a noncompressible appendix was the primary criterion for a diagnosis of acute appendicitis. The overall sensitivity was 89%, the specificity was 95%, and the accuracy was 93%. When the results in women were analyzed separately (n = 49), the overall accuracy was 96%. Several important limitations of US scanning were encountered. There were three false-positive examinations in patients with a sonographically visible appendix whose symptoms spontaneously resolved. Another patient had a normal compressible appendix with a thin (2-mm), symmetric wall surrounded by ascites. There were three nondiagnostic studies (3%) due to inability to compress the cecum and right lower quadrant adequately because of exquisite tenderness (two patients) or massive ascites (one patient). When interpreted in light of the clinical examination, sonography should significantly reduce the rate of false-negative appendectomies, particularly in women.     

Arnold-Chiari II malformation: intraoperative real-time US

Nineteen cases in which high-resolution, intraoperative, real-time sonography was performed during decompression of an Arnold-Chiari II malformation were reviewed. The variations of the often complicated hindbrain anatomic features, well known from autopsy series, were shown in detail with intraoperative sonography. The extent of herniation of the cerebellar vermis, the medulla, and the fourth ventricle into the cervical spinal canal, as well as fourth ventricular dilatation, arachnoid cysts, and cervical hydromyelia, were also demonstrated sonographically. Real-time imaging was useful in guiding the neurosurgeon in decompression of the hindbrain, especially the fourth ventricle, in an anatomic area often obscured visually by intense fibrovascular adhesions.     

Ureterovesical obstruction and megaloureter: diagnosis by real-time US

Forty infants and children were accurately diagnosed with real-time ultrasound (US) as having megaloureter secondary to ureterovesical junction (UVJ) obstruction by an adynamic, distal ureteral segment. Characteristic US findings were dilatation of the distal ureter, often disproportionate to the appearance of the upper collecting system; lower ureteral hyperperistalsis; and a sharply tapered, incurving, distal adynamic segment, 1-3 cm long. Real-time US, used routinely in preliminary evaluation of the urinary tract in children, can facilitate early diagnosis of UVJ obstruction and thus prevent significant loss of renal function.     

Intrahepatic portal venous variations: prevalence with US.

A prospective ultrasound study was undertaken to determine the prevalence of variants of the intrahepatic branching of the portal venous system. Of the 507 patients examined, 55 (10.8%) had trifurcation, 24 (4.7%) had a right posterior segmental branch arising from the main portal vein, 22 (4.3%) had a right anterior segmental branch originating from the left portal vein, and one (0.2%) had absence of the horizontal segment of the left portal vein. Not one patient had complete absence of the right portal vein in this series. The remaining 405 (79.9%) patients had normal distribution of the portal venous system; some patients of the normal group had minor variations in distribution.     

The infant hip: real-time US assessment of acetabular development

Until recently, radiography was the only available means of assessing acetabular development in infants with congenital hip dysplasia. Now that real-time ultrasonography (US) is successfully employed to determine hip position in infancy, it also offers an alternative method for evaluating acetabular development. In a review of 377 US studies of infant hips, the coronal-flexion images, which show a coronal section of the acetabulum with the hip in flexion, were measured to determine the percentage of the femoral head that was covered. Radiographs were measured to determine the acetabular index (angle). Acetabuli with indices exceeding the normal range for the subject's age showed head coverage of less than 33%. The 51 sonograms in this category were all associated with clinical abnormalities, whereas the 107 with coverage greater than 58% were associated with no clinical abnormalities and with consistently normal acetabular indices. The use of US in assessing acetabular development warrants continued investigation.     

US measurement of the subarachnoid space in infants: normal values.

The subarachnoid space was examined with real-time ultrasonography (US) in 89 healthy infants. US of the brain in all infants revealed no abnormalities. Three variables were measured in the coronal plane at the level of the foramen of Monro: the sinocortical width (SCW) ranged from 0.4 to 3.3 mm, the craniocortical width (CCW) from 0.3 to 6.3 mm, and the interhemispheric width (IHW) from 0.5 to 8.2 mm. All variables can be used routinely, as the SCW could be demonstrated in all infants, and the CCW and IHW were demonstrated in 96% (85 of 89). Correlation of sonographic measurements with the independent variables age, head circumference, body weight, and body length was poor. To differentiate normal from pathologically dilated subarachnoid spaces, the following upper limits are proposed on the basis of the 95th percentile: 3 mm for SCW, 4 mm for CCW, and 6 mm for IHW.     

Extrapancreatic spread of acute pancreatitis: new observations with real-time US

Real-time ultrasonography (US) was compared with abdominal computed tomography (CT) in 40 patients with moderate to severe acute pancreatitis. Emphasis was placed on the ability of US to disclose peripancreatic involvement of the anterior pararenal spaces, lesser sac, and transverse mesocolon. When a realtime US scanning technique emphasizing semierect patient positioning and coronal views was used, 20 of 26 lesions in the anterior pararenal space (77%) and 14 of 14 abnormalities in the lesser sac (100%) were visualized. Abnormalities in the transverse mesocolon, however, were poorly detected on US scans. Ten patients (25%) in the study had extrapancreatic abnormalities missed by US. CT remains the imaging method of choice in patients with clinically moderate to severe pancreatitis. In patients with mild pancreatitis, the real-time US technique we describe improved extra-pancreatic visualization compared with previous studies using static scanners. A new US observation of perivascular spread of acute pancreatitis around the splenic and portal veins is described.     

Hepatic artery pseudoaneurysm: diagnosis with real-time and pulsed Doppler US

Duplex ultrasonography (US), consisting of real-time and pulsed Doppler US, was used to identify a pseudoaneurysm in a patient with recurrent bleeding and chronic pancreatitis. The authors present a case that illustrates the limitations of real-time US in evaluating sonolucent masses in pancreatitis and the need for using pulsed Doppler technique.     

Biliary dilatation: defining the level and cause by real-time US

In a 15-month period, 110 patients with subsequently proved biliary dilatation were evaluated with ultrasound (US). The level of dilatation was defined as pancreatic, suprapancreatic, or at the level of the porta hepatis. Causes of dilatation included pancreatitis, choledocholithiasis, neoplasm, and stricture. The distal duct was examined initially on transverse scans obtained with the patient in a semierect right posterior oblique position; the proximal duct was then examined on longitudinal scans obtained with the patient in a supine left posterior oblique position. When this scanning technique was used, US indicated the level of dilatation in 91.8% of cases and suggested the correct cause in 70.9%. Because this approach markedly improves US visualization of the intrapancreatic bile duct, distal obstructing lesions, which are the most common, can be optimally examined.     

Pulsatile masses surrounding vascular prostheses: real-time US color flow imaging

A prospective evaluation of color flow mapping and real-time ultrasound was performed to determine if pseudoaneurysms could be distinguished from other causes of masses surrounding vascular grafts of the lower extremities. Twelve palpable pulsatile masses were imaged. Diagnoses were confirmed at angiography (n = 11), computed tomography (n = 7), aspiration biopsy (n = 5), and operative intervention (n = 6). A swirling pattern of blood flow was seen in six of seven cases of pseudoaneurysm. Lack of flow signals was noted in four of the five collections representing hematoma (n = 2) or infection (n = 2). The seventh case was later shown to be an infected, thrombosed pseudoaneurysm. The single false-positive diagnosis was made early in the series when the flow signals detected were due to transmitted arterial pulsations. The authors conclude that color Doppler flow imaging is useful in the differential diagnosis of pulsatile masses associated with prosthetic grafts. Prosthetic graft pseudoaneurysms have a specific appearance of swirling blood flow arising from a wide neck and are distinguishable from traumatic or iatrogenic pseudoaneurysms of the native vascular tree.     

Comparison of mammography radiation dose values obtained from direct incident air kerma measurements with values from measured X-ray spectral data.

The application of X-rays and ionising radiations for diagnostic radiology requires that the procedure is justified and optimised and that the exposure to the patient is kept as low as possible, without compromising image information. X-ray mammography is considered to be the most sensitive technique currently available for early detection of breast cancer. The magnitude of the absorbed radiation dose to the breast from mammography X-ray beams forms an important part of the quality control of the mammographic examination since it gives an indication of the performance of the mammographic imaging system as well as an estimated risk to the patient. In this work mean glandular dose (MGD) values were obtained at various tube potentials and tube loadings (TL) using direct measurements of the incident air kerma (ESAK) at the surface of a standard breast phantom and also from spectral measurements acquired with a solid-state detector. Comparisons of the MGD values thus derived are presented and the relationship between MGD, phantom thickness, image quality and tube operating parameters is discussed.     

Testicular volume: comparison of orchidometer and US measurements in dogs.

PURPOSE: To compare the accuracy and precision of orchidometer and ultrasonographic (US) measurements of testicular volume in a canine model. MATERIALS AND METHODS: Volume measurements of 18 canine testes were obtained by using Prader and Rochester orchidometers. Testes were scanned with two linear-array US transducers with imaging frequencies of 6-13 MHz and 5-10 MHz. For each transducer, testicular volumes were calculated by using three formulas: length (L) x width (W) x height (H) x 0.52, L x W(2) x 0.52, and L x W x H x 0.71. Testes were weighed following bilateral orchiectomies. True testicular volume was determined by using the formula volume = weight/density. Paired t tests were used to assess whether mean measurement biases differed significantly from zero. The relationship between true and measured volume was evaluated with a linear regression model. RESULTS: US volume measurements demonstrated lower variability and better linear fit compared with orchidometry (R(2) = 0.75-0.90 vs R(2) = 0.14-0.38). The formula L x W x H x 0.71 had the smallest mean bias relative to true volume with use of either transducer over the entire volume range. CONCLUSION: US methods of testicular volume measurement are more accurate and precise than orchidometry. The formula L x W x H x 0.71 provides a superior estimate of testicular volume and should be used in clinical practice.     

Testicular tumors: prospective analysis of real-time US patterns and abdominal staging

Echomorphologic features of 57 testicular lesions (48 neoplasms, nine benign lesions) were analyzed prospectively by means of high-resolution real-time ultrasonography (US). There was a broad spectrum of texture patterns for testicular malignancies, 92% of which exhibited a predominantly decreased echogenicity compared with that of normal tissue. US findings alone could not be used to make a specific prediction of malignant disease or to classify a neoplasm histologically. However, different kinds of tumors exhibited characteristic echomorphologic features that corresponded to their gross morphologic appearance; a knowledge of these echomorphologic features is extremely useful for the US differentiation of tumors from nonneoplastic scrotal pathologic conditions. All neoplasms in this series displayed distinct abnormalities in parenchymal texture, and all were detected with US. The sensitivity and predictive value of a normal sonogram were as high as 100%. With regard to the detection of retroperitoneal lymph node metastases from testicular tumors, abdominal US had an overall accuracy rate of 96% and was of superior diagnostic value compared with bipedal lymphangiography.     

Anatomic variations and abnormalities in the diaphragm seen with US

The authors report their experience with diaphragmatic structures that simulate intrahepatic masses at abdominal ultrasonography (US). In a series of 74 patients, diaphragmatic slips were the most common finding (34 patients). The slips could be differentiated from masses by scanning along their long axis to demonstrate elongated structures with multiple linear echoes. Scalloping of the diaphragm, associated with multiple slips, was seen in 10 patients. Partial eventration was found in 23. Inversion of a hemidiaphragm, caused by a large pleural effusion or intrathoracic mass, was seen in 13 patients. Pleural masses affecting the diaphragm were seen in 13 patients; focal hypertrophy of a diaphragmatic crus simulated a mass in three. Real-time US allowed the differentiation of diaphragmatic abnormalities from lesions.     

腕部第一伸肌间隙解剖变异:超声检查的准确性

目的评价超声检查对诊断腕部第一伸肌间隙解剖变异的准确性。材料与方法该研究得到了人体捐赠部门的批准。由2名观察者对40具未行防腐处理的尸体(15具男     

Ultrasonography of the normal adrenal glands: a study using linear-array real-time equipment

The adrenal glands were evaluated in 70 normal volunteers using linear-array real-time ultrasonography. All the scanning approaches described for manual B-scanning were used and, on the left side, longitudinal scans along the axillary lines were also performed. The right adrenal gland was imaged in 68 of the 70 volunteers and the left gland in 63. The dynamic capabilities of real-time equipment were of great help for proper localisation and identification of the glands. Changes in the scanning plane demonstrated variations in the adrenal morphology, because different portions of the gland were encountered by the scanning beam.     

Acute liver rejection: accuracy and predictive values of doppler US measurements--initial experience

PURPOSE: To prospectively evaluate accuracy and predictive values of Doppler ultrasonographic (US) measurement of portal blood velocity (PBV) and splenic pulsatility index (SPI) in diagnosis of clinically relevant acute rejection in patients with clinicobiochemical hepatic dysfunction after orthotopic liver transplantation (OLT). MATERIALS AND METHODS: Study was approved by the institutional review board, and protocol conformed to ethical guidelines of Declaration of Helsinki. Patient informed consent was obtained. In 27 patients with OLT (23 men, four women; mean age, 48 years; range, 27-64 years), PBV and SPI were measured at Doppler US within 48 hours before or after liver biopsy for clinically suspected acute rejection. Biopsy specimens were assigned scores according to Banff method, and rejection activity index (RAI) was calculated. RAI score of 4 or greater was considered clinically relevant acute rejection. Doppler US parameters were analyzed as absolute values and as percentage point changes with respect to values obtained at last examination before rejection was suspected. Information from two Doppler US parameters was combined; Doppler US composite index was calculated. Statistical tests were conducted to assess accuracy, sensitivity, specificity, and predictive values of Doppler US parameters in diagnosis of graft rejection. RESULTS: Clinically relevant acute rejection was diagnosed in nine patients. Median time from OLT until histologic diagnosis of acute rejection was 8 days (range, 5-20 days). Rejection was associated with a marked reduction in mean PBV (-43% +/- 5 [standard error of the mean]) and a slight increase in SPI (+12% +/- 16). The calculated Doppler US composite index was strictly related to severity of rejection (P < .001). When applied retrospectively, this index had good accuracy (88%) for prediction of rejection (specificity, 89%; sensitivity, 86%; negative predictive value, 94%). CONCLUSION: During the first weeks after OLT, a marked decrease in PBV associated with increased SPI supports suspicion of clinically relevant acute rejection.