Diagnostic evaluation of patients with suspected cholecystitis

In this article, imaging techniques for examining patients with suspected cholecystitis are discussed. In particular, acute cholecystitis and the roles of ultrasonography and radionuclide imaging are stressed, including each of their specific advantages and limitations.

Computed tomography of silent abdominal abscesses

Computed tomographic (CT) findings are reviewed in nine patients with clinically unsuspected abdominal abscesses. None of the patients in this series had significant fever or leukocytosis. Localized pain or a palpable mass was the primary clinical feature in seven patients. Computed tomography demonstrated encapsulated fluid collections without gas in five patients representing chronic abscess. Computed tomography was diagnostic of an abscess in three patients and guided aspiration was helpful in demonstrating an abscess in two other patients. The inability to make a correct preoperative diagnosis of an abscess in four of the nine cases was due to a low level of clinical suspicion, a nonspecific CT appearance, and failure to perform diagnostic aspiration.

Sonography of testicular trauma

The sonographic features were reviewed in 30 cases of testicular trauma. Sonography correctly diagnosed testicular rupture in 12 surgically proven cases. Two additional cases of testicular rupture were diagnosed by sonography in patients who refused surgery. One false-positive diagnosis occurred in a patient with a large scrotal hematoma. There were no known false-negative diagnoses. Discrete fracture planes often are not identified by sonography in cases of testicular rupture. However, any alteration of the normal testicular echogenicity in traumatized patients suggests testicular rupture and requires surgery.

Ultrasonography for the diagnosis and staging of blunt scrotal trauma

Of 19 patients with blunt testicular trauma diagnosed and staged correctly by physical examination and ultrasonography 10 were explored surgically and 9 were managed nonoperatively (treatment was supported by ultrasonography). Fractured testicles occurred in 5 of the 10 explored patients and were repaired surgically, and in 2 of the 9 conservatively managed patients. These 2 patients refused an operation. Ultrasonography can show disruption of the testicle as evidenced by intratesticular lucencies representing hematoma, extruded testicular parenchyma or a fragmented testicle. The tunica albuginea is too thin to be defined consistently and, thus, it could not be used as a parameter for disruption in the 10 patients who were explored surgically. Ultrasonography used in conjunction with a thorough physical examination is highly accurate, readily available, noninvasive and gives minimal discomfort. This modality can be used to follow nonoperative scrotal injury to resolution. With the availability of high resolution real-time ultrasonography more rapid and reliable screening of the scrotum is possible.

Ultrasonographic diagnosis of medullary cystic disease

The authors have successfully diagnosed medullary cystic disease on the basis of the sonographic and computed tomographic appearances of the characteristic small cysts. The disease is described and its differential diagnosis is considered.

Septa of Bertin: a sonographic pseudotumor

The sonographic features of six renal "pseudotumors" representing septa of Bertin are described. Septa of Bertin are isoechoic with renal parenchyma and demonstrate a characteristic splaying of the central sinus echoes. CT performed in all six cases revealed the "mass" to be normally enhancing renal cortex. The characteristic radiographic features of septa of Bertin are reviewed and the split sinus sign is discussed.

Ultrasonographic findings in peptic ulcer disease and pancreatitis that simulate primary gallbladder disease

The ultrasonographic findings in two patients with peptic ulcer disease and one patient with acute pancreatitis are reported. In each case, the sonographic appearance simulated intrinsic gallbladder disease. Two patients had focal pericholecystic fluid collections and one had an inflammatory mass adjacent to the gallbladder. Each patient also demonstrated gallbladder wall thickening. Findings of a pericholecystic fluid collection or an inflammatory mass adjacent to the gallbladder appear to be nonspecific for cholecystitis, and should also suggest inflammation of adjacent organs.

Gangrenous cholecystitis: diagnosis by ultrasound

Sonographic findings were analyzed in 19 patients with surgically proved gangrenous cholecystitis. In 8 patients (42%), there were no specific features that would allow differentiation from typical uncomplicated acute cholecystitis. However, in 11 patients (58%) atypical findings were present, including intraluminal membranes and/or marked irregularities of the gallbladder wall. These features are unusual in uncomplicated acute cholecystitis and should prompt close clinical observation for possible gangrenous cholecystitis.

Computed tomography of choledocholithiasis

Computed tomography (CT) correctly diagnosed common bile duct stones in 19 (90%) of 21 surgically proven cases. CT demonstrated calculi in all 13 patients with calcium bilirubinate common duct stones and six of eight patients with predominantly cholesterol stones. There were two false-negative diagnoses in patients with cholesterol calculi scanned at 1 cm intervals. Cholesterol stones are nearly isodense with bile and may be difficult to visualize in the common duct by routine scanning techniques. There are three suggestive CT features of cholesterol common duct calculi: (1) abrupt termination of the distal common bile duct without an obstructing mass, (2) a faint rim of increased density along the peripheral margin of a low-density calculus, and (3) mottled areas of increased density centrally within a calculus elevating its CT number above values for normal bile. Modification of scanning technique to obtain high-resolution images of the extrahepatic biliary tree is stressed to optimize visualization of the above findings.

Ultrasonographic differentiation of the gestational sac of early intrauterine pregnancy from the pseudogestational sac of ectopic pregnancy

A retrospective review of 128 consecutively scanned pregnant patients who had either early intrauterine pregnancies (IUPs) or ectopic pregnancies was performed to determine the accuracy of the finding of an intrauterine double decidual sac (DDS) in distinguishing between these two groups of patients. The presence of a DDS correlated with an IUP in 59 of 60 patients (98.3%). Of 68 patients who lacked a DDS, only four had normal IUPs; the remaining patients had either ectopic pregnancies or abnormal IUPs. Results of this study suggest that the finding of a DDS at ultrasonography is useful in making an early diagnosis of IUP, while its absence strongly suggests either an ectopic pregnancy or an abnormal IUP.

CT and sonography of severe renal and perirenal infections

Twelve patients with urosepsis and severe renal or perirenal infections were evaluated with both computed tomography (CT) and sonography. Six patients had nine proven renal or perirenal abscesses larger than 2 cm in diameter. One patient had multiple microabscesses smaller than 1 cm. Five patients had CT or sonographic evidence of focal or multifocal bacterial nephritis. Computed tomography correctly diagnosed all renal (six) and perirenal (three) abscesses. Sonography was falsely negative in a patient with multiple microabscesses and in another patient with a gas-forming perinephric abscess. In one patient with four bilateral renal abscesses, sonography correctly diagnosed only one of the abscesses. In the five patients with focal or multifocal bacterial nephritis, CT demonstrated poorly defined, poorly enhancing lesions in all cases. Sonography was normal in three of these patients. Although this report is based on a limited experience, computed tomography seems to be the more sensitive method of evaluating severe renal and perirenal infections.

Choledocholithiasis and cystic duct obstruction: difficult ultrasonographic diagnosis

Ultrasonography of 53 patients with stones in either the common bile duct (CBD) or the gallbladder neck/cystic duct revealed respective sensitivities of only 30% and 29% for detection of calculi. The data, which were collected over a period of 40 months, were also analyzed with respect to our early experience (first 24 months) versus our later experience (last 16 months). Although there was no improvement in the diagnosis of gallbladder neck/cystic duct calculi (only those in the gallbladder neck could be identified), significant improvement occurred in the diagnosis of choledocholithiasis, with a sensitivity of 15% in the early period and a sensitivity of 55% in the later period. In part this was due to greater dependence upon real-time equipment and more emphasis on the examination of the distal CBD. A limiting factor in the diagnosis of choledocholithiasis was the normal caliber of the duct in 30% of these patients. Despite improved equipment and technique, ultrasonography cannot detect cystic duct obstruction, and the ultrasonographic diagnosis of CBD calculi remains difficult.

The importance of ultrasonic side-lobe artifacts

Transducer side lobes consist of multiple low-intensity sound beams located outside of the main ultrasound beam. Although the echoes generated by side lobes originate outside of the main beam, they appear as specular or diffuse artifactual echoes within the beam. They are visible with both static and real-time equipment. Specular side-lobe artifacts occur near strong, curved, highly reflecting surfaces such as the diaphragm, or near large cystic masses such as the urinary bladder or gallbladder. Diffuse artifacts originate from bowel gas adjacent to cystic structures. These echoes can be confused with particulate material or sludge in organs such as the urinary bladder and gallbladder, or in abnormal cystic masses. We illustrate the genesis of these artifactual echoes and provide clinical examples of commonly visualized side-lobe artifacts.

Noninvasive imaging of unusual regenerating nodules in the cirrhotic liver

Despite the common occurrence of regenerating liver nodules, little has been written regarding their ultrasound or computed tomographic appearance. In the great majority of cases, they have an echo texture and CT number identical to surrounding hepatic parenchyma. Exceptionally, as in the 2 cases described, they can mimic a malignant neoplasm. Because radionuclide imaging almost always demonstrates uptake over a regenerating nodule, this modality should be used in suspicious cases in conjunction with either ultrasound or computed tomography in order to exclude a malignancy.

Echogenic clot: a useful sign of pelvic hemoperitoneum

The sonograms of 34 patients with surgically proved pelvic hemoperitoneum were reviewed. In 15 of these patients clotted blood was found at surgery in the pelvis or cul-de-sac. In nine of these patients (60%), ultrasound demonstrated echogenic fluid collections or "masses" with an echogenicity equal to or greater than the uterus. Because anechoic fluid in the pelvis is a nonspecific finding, awareness that clotted blood can be highly echogenic may be of considerable value in the differential diagnosis of pelvic fluid collections. The limitations and pitfalls in interpreting this finding are discussed.

High-resolution real-time sonography of fetal cardiovascular anatomy

With high-resolution real-time sonography it is possible to visualize normal fetal cardiovascular structures in a high percentage of second- and third-trimester pregnancies. At present the optimal view for cardiac visualization is the four-chamber view, which affords simultaneous imaging of the atria, ventricles, and atrioventricular and interventricular septa. The fetal aortic arch can be readily demonstrated in most patients. The most significant factor limiting cardiac examination is fetal position, since it is extremely difficult to scan prone fetuses. High-resolution real-time sonography has the potential to permit in utero diagnosis of major structural cardiac anomalies and should become part of the routine ultrasound screening for congenital anomalies.

Ultrasound evaluation of ectopic pregnancy

The combined use of a serum radioimmunoassay pregnancy test and high resolution utrasonography allows a more direct approach to be made in the diagnosis of ectopic pregnancy. It is important for ultrasonographers to understand the limitations of the more readily available immunologic pregnancy tests in order to avoid misinterpreting ultrasonograms in the event that a pregnancy test is either falsely positive or falsely negative. Clinical suspicion is mandatory if the early diagnosis of ectopic pregnancy is to be made. The referring physician should take advantage of the highly accurate information resulting from the combined findings of a positive serum HCG and the ultrasonographic images. If the statistics regarding diagnostic delay and tubal rupture are to be improved, these tests should be obtained when a patient is initially evaluated. It is important to recognize that the ultrasonographic interpretation rests primarily upon the uterine findings. A normal viable intrauterine pregnancy essentially excludes the diagnosis of ectopic pregnancy. Other uterine appearances may result from an early intrauterine pregnancy, an abnormal intrauterine gestational event, or, as in approximately 1 per cent of pregnancies, an ectopic gestation. Subsequent evaluation in suspicious cases may require a variety of tests including serial HCG determinations, repeat ultrasound examination, uterine dilatation and curettage, culdocentesis, or laparoscopy. It is impossible to recommend a specific schematic approach for any given patient. In part, the pattern of management depends upon availability of tests, the presence or absence of adnexal or cul-de-sac findings, and, of course, the clinical status of the patient.U

Recurrent pyogenic cholangitis in Asian immigrants. Use of ultrasonography, computed tomography, and cholangiography

Five cases of recurrent pyogenic cholangitis (RPC) were studied by ultrasonography, computed tomography (CT), and cholangiography. All patients were recent immigrants from the Orient or Indonesia and had had recurrent attacks of cholangitis for many years. The bile was infected by E. coli and the biliary ducts were dilated; in addition, extrahepatic bile-pigment calculi were present in all 5 and intrahepatic calculi in 4. Abdominal ultrasound usually failed to demonstrate duct calculi and extrahepatic dilatation due to the soft, mud-like consistency of the stones. CT was successful in showing the calculi and the full extent of dilatation. The authors conclude that preoperative diagnosis of RPC is best achieved by awareness of the characteristic clinical presentation and the findings on abdominal CT. Preoperative cholangiography provides excellent detail, but poses the danger of biliary sepsis requiring antibiotics.

Computed tomography of splenic trauma

Fifty patients with abdominal trauma and possible splenic injury were evaluated by computed tomography (CT). CT correctly diagnosed 21 of 22 surgically proved traumatic lesions of the spleen (96%). Twenty-seven patients had no evidence of splenic injury. This was confirmed at operation in 1 patient and clinical follow-up in 26. There were one false negative and one false positive. In 5 patients (10%), CT demonstrated other clinically significant lesions, including hepatic or renal lacerations in 3 and large retroperitoneal hematomas in 2. In adolescents and adults, CT is an accurate, noninvasive method of rapidly diagnosing splenic trauma and associated injuries. Further experience is needed to assess its usefulness in evaluating splenic injuries in infants and small children.

Sonography of the low-lying placenta: value of Trendelenburg and traction scans

In later stages of pregnancy, acoustic shadowing from a fetal head may obscure the termination of a low-lying placenta and prevent sonographic imaging of the internal cervical os. The evaluation of a marginal or partial placenta previa in this setting may be difficult. Placing the mother in Trendelenburg position and applying gentle upward traction on the fetal head allows amniotic fluid to cover the lower uterine segments. This provides an acoustic window to visualize the relation of the termination of the placenta to the internal os. This technique was evaluated prospectively in a series of 217 patients and was successful in 49 of 50 patients in whom conventional studies failed to image the termination of the placenta or the region of the internal os.

Ultrasonic evaluation of patients with acute right upper quadrant pain

To define the role of ultrasound in evaluating acute right upper quadrant pain, a prospective study was performed on 52 patients having clinically suspected acute cholecystitis. Ultrasonographic determination of acute or chronic cholecystitis, or diagnosis of a normal gallbladder, was based on analysis of location of tenderness, calculi, sludge, and wall thickness. The diagnosis of acute cholecystitis (34.6% of patients) was based on the highly significant observations of focal gallbladder tenderness and calculi. Sludge and wall thickening were also statistically significant, but to a lesser degree. Cholelithiasis allowed differentiation of patients with chronic cholecystitis (32.7%) from patients with normal gallbladders (32.7%). Neither of these two groups had significant focal gallbladder tenderness, sludge, or thickened walls. Because acute cholecystitis is found in the minority of patients with acute right upper quadrant pain, and because ultrasound is rapid, accurate, and noninvasive, it should be the initial modality used to evaluate these patients.

Rapid change in caliber of the nonobstructed common duct

A case of a postcholecystectomy patient is presented in which an initially grossly dilated common hepatic duct returned to normal size within several minutes. We have tried to explain this phenomenon using known facts abut bile duct elasticity and bile flow, and conclude that such rapid size change probably only occurs in those patients without a normally functioning gallbladder.