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PURPOSE: To present our early experience with a classification scheme for categorizing focal liver lesions on the basis of the enhancement patterns that they exhibit in the arterial phase of computed tomography (CT) and to determine whether particular enhancement patterns suggest particular diagnoses. MATERIALS AND METHODS: The authors reviewed arterial phase CT images in 100 consecutive patients with focal liver lesions, excluding simple cysts. The enhancement pattern of the dominant or representative lesion in each patient was classified into one of five categories-homogeneous, abnormal internal vessels or variegated, peripheral puddles, complete ring, or incomplete ring-by three radiologists blinded to the proved diagnosis. Lesions without enhancement were recorded separately. Agreement was reached by consensus in all cases. Standards of reference included findings at histologic examination, correlative imaging, or clinical and imaging follow-up. RESULTS: Ninety-two percent of the 100 lesions demonstrated arterial phase enhancement. Patterns associated with positive predictive values of 82% or greater and specificity of 80% or greater included abnormal internal vessels or variegated (hepatocellular carcinoma), peripheral puddles (hemangioma), and complete ring (metastasis). CONCLUSION: The appearance of hepatic lesions in the arterial phase of enhancement has potential use in the determination of specific diagnoses. The classification scheme used in this study may be a useful tool for the interpretation of arterial phase CT studies.

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The purpose of this study was to determine the utility of magnetic resonance imaging (MRI) in detecting and localizing clinically non-apparent postpartum pelvic hematomas, and to describe the therapeutic implications of MRI in these patients. MRI examinations were performed on seven women with pelvic pain and/or fullness following difficult vaginal deliveries. None had clinically evident hematomas, and none were scheduled for surgery. Hematomas in the pelvis were identified with conventional T1-weighted, and conventional and fast spin echo T2-weighted sequences. Intravenous contrast was not used. Pelvic hematomas were identified in contiguity with the vagina, cervix, and bladder, within the broad ligament, and in the presacral space. In two patients, hematomas were confined to the perivaginal and pericervical regions. In three patients, perivaginal hematomas extended between the double layers of the broad ligaments. In one patient, a perivaginal hematoma extended into the perivesical space. In one patient, a hematoma was identified only within the presacral space. Based on MRI as the only contributory imaging study, five patients were treated successfully with invasive means and two patients were managed successfully with conservative means. MRI successfully detects and localizes postpartum hematomas, information that often is unavailable from the clinical examination. This information facilitates decisions regarding the need for intervention and the appropriate type of procedure when intervention is necessary for this potentially life-threatening problem. We advocate the use of MRI to evaluate patients at risk for postpartum hemorrhage following difficult vaginal deliveries.

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Patients with right lower quadrant (RLQ) pain referred for imaging studies with a clinical diagnosis of appendicitis may have other pathologic conditions mimicking appendicitis. Appropriate diagnostic imaging may establish other specific diagnoses and thereby play a significant role in determining proper medical or surgical treatment. In this pictorial essay, we present a spectrum of imaging findings in patients whose clinical features were suggestive of appendicitis, but the diagnoses of a broad spectrum of other diseases were established with the imaging studies. The differential diagnoses of diseases mimicking appendicitis are reviewed.

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GAN tumors are rare and their diagnosis and distinction from other gastrointestinal stromal tumors is based on electron microscopy findings. Although no specific distinctive diagnostic imaging features are seen, this diagnosis should be considered when a large solid mass adjacent to a bowel loop shows the presence of air.

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OBJECTIVE: The purposes of this investigation were to compare prospectively the pattern and extent of cystic artery flow revealed by power Doppler sonography and color Doppler sonography in patients with normal gallbladders and to analyze the potential implications of these findings for power Doppler sonography in diagnosing acute cholecystitis. SUBJECTS AND METHODS: The cystic arteries of 142 patients (79 women and 63 men) with normal gallbladders were imaged with both power Doppler sonography and color Doppler sonography using 5-MHz transducers and settings optimized to reveal low-volume flow. The presence or absence of cystic artery flow and the anatomic extent of its visualization were recorded for each patient. RESULTS: Power Doppler sonography revealed flow in 73% of patients with normal gallbladders compared with 53% revealed by color Doppler sonography. Cystic artery flow within the distal fundal quartile was revealed by power Doppler sonography in 20% of patients and flow spanning greater than 50% of the anterior gallbladder wall was revealed by power Doppler sonography in 17% of patients. These findings differed from those of color Doppler sonography at a highly significant level (p < .0001, chi-square test). CONCLUSIONS: Power Doppler sonography is significantly more sensitive than color Doppler sonography for revealing cystic artery flow in patients with normal gallbladders. The flow patterns in patients with normal gallbladders obtained with power Doppler sonography overlap flow patterns previously reported as fairly specific criteria for diagnosing acute cholecystitis using color Doppler sonography, namely, flow within the distal fundal quartile and flow spanning greater than 50% of the anterior gallbladder wall. Accordingly, these color Doppler sonography criteria are not applicable to the diagnosis of acute cholecystitis with power Doppler sonography. Different power Doppler sonography criteria are necessary for the diagnosis of acute cholecystitis.

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Most patients presenting with right lower quadrant pain are clinically suspected to have acute appendicitis. However, sonographic findings other than appendicitis are detected in patients who are referred for ultrasound to rule out appendicitis. This pictorial essay delineates a number of unsuspected pathological conditions revealed by ultrasound examination of the right lower quadrant that do not involve the appendix but closely mimic acute appendicitis. Imaging studies play a significant role in preoperative diagnosis and determination of proper treatment. The patient can undergo triage for proper further workup and surgical versus nonsurgical management. Acute appendicitis initially was considered on clinical presentation in all of our patients. The correct diagnosis of other pathological conditions was made on the basis of sonographic findings.

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Massive benign or malignant thoracic tumors in children may arise from the chest wall, pleura, lung parenchyma, or mediastinum and may be primary or secondary. On initial chest radiographs, these masses usually appear as an opaque hemithorax or an obvious large opaque mass. If the site of origin of the intrathoracic tumor can be determined, the differential diagnosis may be based on the location of the tumor, the age of the patient, and distinguishing imaging features. The purpose of this essay is to illustrate imaging findings of large intrathoracic masses that cause an opaque hemithorax on initial chest radiographs. Chest wall masses that do not grow primarily intrathoracically are not included in this discussion.

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Color Doppler sonography was used to evaluate the length and distribution of the cystic artery in the gallbladder wall in 115 normal adults and in 54 patients with surgically proved cholecystitis. All patients were scanned with a 5 MHz curved array transducer optimized for low volume color sensitivity. A specific attempt was made to visualize the cystic artery throughout its course. Spectral Doppler waveforms were obtained to document arterial flow. The length of the cystic artery visualized was analyzed as a quartile percentage length of the anterior gallbladder wall. The distribution of the cystic artery flow also was analyzed in specific quartiles. Of 54 patients with acute cholecystitis, 26% had cystic artery length greater than half of the anterior gallbladder wall, compared with 2% of 115 normal controls (P < 0.001); 19% of patients with cholecystitis had flow in the distal (fundal) quartile, compared to 0% of normal controls (P < 0.0001). Although the presence or absence of flow in the gallbladder is not a reliable finding to establish the diagnosis of acute cholecystitis, length of cystic artery visualized is a potentially useful criterion to suggest the diagnosis of acute cholecystitis, especially in cases in which flow in the distal fundal quartile of the gallbladder. The usefulness of color Doppler sonography in acute cholecystitis is limited owing to the fact that it is insensitive, and many patients with cholecystitis have no detectable flow or have normal flow patterns.

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Magnetic resonance imaging is becoming increasingly useful in characterizing adnexal masses, whereas endovaginal ultrasound is an invaluable technique for examining the uterus and adnexa. This pictorial essay depicts the internal architectural details necessary for characterization of various adnexal masses imaged with both EVU and MR imaging. Forty consecutive examinations that revealed 51 adnexal masses were reviewed. All patients had MR imaging and EVU examinations within 1 week of each other. T1- and T2-weighted images in coronal, axial, and sagittal planes were included. Fat suppression technique also was used in selected cases. EVU, because of its high spatial resolution, was able to depict better internal architectural details, allowing specific diagnosis of most adnexal masses, whereas MR imaging was superior in differentiating hemorrhagic masses from dermoids when specific fat suppression techniques were used.

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PURPOSE: To assess the reliability of gray-scale and color and duplex Doppler ultrasound (US) in making a specific diagnosis of malignant ovarian tumor. MATERIALS AND METHODS: Forty-two women with 50 adnexal masses underwent endovaginal and color and duplex Doppler US. Morphologic characteristics were evaluated with endovaginal US, and flow velocity patterns were evaluated with color and duplex Doppler US. The results were compared with pathologic findings. RESULTS: At pathologic examination, 40 masses (80%) were benign, one (2%) was borderline malignant, and nine (18%) were malignant. Endovaginal US enabled correct diagnosis of 38 of the 40 benign masses (95%) and all nine malignant masses (100%). Color and duplex Doppler US enabled correct diagnosis of 33 benign masses (82%) and seven malignant masses (78%). CONCLUSION: Because there is an overlap in the resistive index (RI) values of benign and malignant masses, RI values alone cannot be relied on. Combining the detailed analysis of internal architectural appearance with the flow velocity patterns obtained at pulsed Doppler US increases the specificity in the diagnosis of adnexal masses.

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Graded compression sonography has proven to be of significant clinical value in the assessment of patients with right lower quadrant pain and possible appendicitis [1-3]. Despite its proven utility, a number of imaging pitfalls must be kept in mind when sonograms of the right lower quadrant are interpreted. The purpose of this pictorial essay is to illustrate a number of important limitations and areas of interpretive difficulty in sonography for appendicitis.

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Four boys with abdominal tuberculosis, one of whom had acquired immunodeficiency syndrome, are presented. Abdominal imaging findings on plain radiography, ultrasonography, computed tomography, and gastrointestinal contrast studies included tuberculous peritonitis and ascites in all patients, tuberculous adenopathy in two, gastrointestinal tuberculosis in two, and omental tuberculosis in two. The radiographic features particularly characteristic of abdominal tuberculosis were: (1) low attenuating adenopathy with rim enhancement, (2) omental or ileocecal inflammatory mass, (3) high density ascites, and (4) gastrointestinal enteritis involving the ileocecal region. All patients had acid-fast bacilli identified in cultures of bodily fluids and/or pathologic specimens and three patients had cultures positive for Mycobacterium tuberculosis. The patient with a negative culture had a positive PPD skin test and a surgical specimen showing caseating granulomata and acid-fast bacilli in the omentum. The radiologist must maintain a high degree of suspicion for abdominal tuberculosis particularly in normal or immunosuppressed children with acquired immunodeficiency syndrome. Fine needle aspiration and biopsy of abdominal adenopathy, inflammatory mass or ascites may be necessary for diagnosis.

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This report presents the common and unusual appearances of fatty infiltration of the liver (FIL) on ultrasound (US) and computerized tomography (CT) from pathological, proven cases. Potential diagnostic pitfalls and methods of avoiding these pitfalls will be emphasized. Generalized and the geographic pattern of FIL are well recognized. Focal FIL and focal sparring of the liver have a number of atypical appearances. Focal sparring has several distinct patterns (pseudotumor, glove pattern and possible metastasis), which may be confused with other pathologies. Likewise, focal FIL may simulate a space-occupied mass. Among the more helpful features used to distinguish focal FIL from other abnormalities include its lack of mass effect, low density on CT combined with increased echogenicity on US.

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In a prospective study, 32 women with suspected pelvic masses at physical examination underwent both endovaginal ultrasound (US) and magnetic resonance (MR) imaging to compare their ability in diagnosis of adnexal masses. Criteria for the diagnosis of various types of adnexal masses with MR imaging and endovaginal US were prospectively defined, and the ability of either modality to allow a specific diagnosis was assessed. For each modality, measures of sensitivity, specificity, and accuracy were obtained. Results indicated higher diagnostic capability of endovaginal US for simple cysts (five of five), hemorrhagic cysts (eight of nine), endometriomas (nine of 14), and ovarian carcinomas (three of three). MR imaging demonstrated higher diagnostic capability for dermoids (three of three). MR imaging and endovaginal US showed equal diagnostic capability for pedunculated fibroids (two of two). For all masses, observers, and observations, the overall sensitivity of endovaginal US was 76% versus 49% for MR imaging, and the overall accuracy of endovaginal US was 83% versus 70% for MR imaging. The authors suggest that endovaginal US is a better modality than MR imaging for the assessment of suspected pelvic masses.

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Endovaginal sonography is rapidly becoming the diagnostic procedure of choice when evaluating patients with early pregnancy and assessing uterine abnormalities. However, there has been relatively little discussion of endovaginal sonography in the evaluation of adnexal masses. Using endovaginal sonography we studied 50 patients with clinically suspected adnexal masses, in whom transabdominal sonography was either suboptimal or failed to adequately characterize the mass. The purpose of this pictorial essay is to depict the normal anatomy of the ovaries and adnexa and highlight the unique contribution of endovaginal sonography in diagnosing a variety of adnexal masses, including tubal and ovarian lesions.

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During a 31-month period, evidence of gonadal vein thrombosis (GVT) was demonstrated by computed tomography (CT) in seven patients who had a broad spectrum of acute gastrointestinal inflammatory lesions, including diverticulitis, ulcerative colitis, Crohn disease, appendicitis with abscess, and perforated appendix with pseudomembranous colitis. All patients had lower abdominal pain, tenderness, fever, and leukocytosis. CT demonstrated thrombus through the length of the gonadal vein in each patient; the entire lumen of the vein was filled. No symptoms relating to GVT were present. GVT may resolve with treatment of the underlying enteric disease alone, and anticoagulant therapy may not be necessary.

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