Ania Z. Kielar

Leiomyomas beyond the Uterus: Unusual Locations, Rare Manifestations

Uterine leiomyomas affect 20%-30% of women older than 35 years. Extrauterine leiomyomas are rarer, and they present a greater diagnostic challenge: These histologically benign tumors, which originate from smooth muscle cells, usually arise in the genitourinary tract (in the vulva, ovaries, urethra, and urinary bladder) but may arise in nearly any anatomic site. In addition, unusual growth patterns may be seen, including benign metastasizing leiomyoma, disseminated peritoneal leiomyomatosis, intravenous leiomyomatosis, parasitic leiomyoma, and retroperitoneal growth. In the presence of such a pattern, a synchronous uterine leiomyoma or a previous hysterectomy for removal of a primary uterine tumor may be indicative of the diagnosis. However, some extrauterine leiomyomas may mimic malignancies, and serious diagnostic errors may result. The most useful modalities for detecting extrauterine leiomyomas are ultrasonography, computed tomography, and magnetic resonance (MR) imaging. The superb contrast resolution and multiplanar capabilities of MR imaging make it particularly valuable for characterizing these tumors, which usually show low signal intensity similar to that of smooth muscle on T2-weighted images. The radiologists recognition of this and other characteristic features may help steer the clinician toward timely, appropriate management and away from unnecessary, potentially harmful treatment.

Imaging of pregnant and lactating patients: part 1, evidence-based review and recommendations.

OBJECTIVEnThe objectives of this article are to discuss the current evidence-based recommendations regarding radiation dose concerns, the use of iodinated and gadolinium-based contrast agents, and the comparative advantages of multimodality imaging (ultrasound, CT, and MRI) during pregnancy and lactation. We also discuss the use of imaging to evaluate pregnant trauma patients.nnnCONCLUSIONnMaternal and fetal radiation exposure and dose are affected by gestational age, anatomic site, modality, and technique. The use of iodinated and gadolinium-based contrast agents during pregnancy and lactation has not been well studied in human subjects. Imaging should be used to evaluate pregnant trauma patients only when the benefits outweigh the risks.

Percutaneous Image-guided Biopsy of the Spleen: Systematic Review and Meta-Analysis of the Complication Rate and Diagnostic Accuracy

PURPOSEnTo use meta-analysis to determine the complication rate and diagnostic accuracy of image-guided percutaneous needle biopsy of the spleen.nnnMATERIALS AND METHODSnSeveral electronic databases were searched through July 2010 without language restrictions. Two reviewers independently selected studies that met the inclusion criteria for the diagnostic accuracy and complication rate arms of the study. Study data were independently extracted by the two reviewers. The primary 2 × 2 data were investigated with a random-effects meta-analysis of sensitivity and specificity. The complication rate data were investigated with a random-effects meta-analysis; sensitivity analysis of complication rate, excluding needles larger than 18 gauge, was performed.nnnRESULTSnFour studies met the inclusion criteria for the diagnostic accuracy arm (639 patients), and nine met the inclusion criteria for the complication rate arm (741 patients). The meta-analysis showed a pooled sensitivity of 87.0% (95% confidence interval [CI]: 80.7%, 91.4%) and specificity of 96.4% (95% CI: 81.4%, 99.4%). The pooled major complication rate was 2.2% (95% CI: 0.8%, 5.6%). Sensitivity analysis with the removal of biopsies performed with needles larger than 18 gauge showed a major complication rate of 1.3% (95% CI: 0.6%, 2.5%). The most commonly encountered complications were hemorrhage followed by pain.nnnCONCLUSIONnImage-guided percutaneous biopsy of the spleen demonstrates high diagnostic accuracy and a major complication rate, for needles 18 gauge or smaller, that is similar to that reported for the liver and kidney. This technique should be considered a favorable alternative to splenectomy.

Ten uncommon and unusual variants of renal angiomyolipoma (AML): radiologic–pathologic correlation

Classic (triphasic) renal angiomyolipoma (AML) is currently classified as a neoplasm of perivascular epithelioid cells. For diagnosis of AML, the use of thin-section non-contrast enhanced CT (NECT) improves diagnostic accuracy; however, identifying gross fat within a very small AML is challenging and often better performed with chemical-shift MRI. Although the presence of gross intra-tumoural fat is essentially diagnostic of AML; co-existing intra-tumoural fat and calcification may represent renal cell carcinoma (RCC). Differentiating AML from retroperitoneal sarcoma can be difficult when AML is large; the feeding vessel and claw signs are suggestive imaging findings. AML can haemorrhage, with intra-tumoural aneurysm size >5xa0mm a more specific predictor of future haemorrhage than tumor size >4xa0cm. Diagnosis of AML in the setting of acute haemorrhage is complex; comparison studies or follow-up imaging may be required. Not all AML contain gross fat and imaging features of AML without visible fat overlap with RCC; however, homogeneity, hyperdensity at NECT, low T2-weighted signal intensity and, microscopic fat are suggestive features. Patients with tuberous sclerosis often demonstrate a combination of classic and minimal fat AML, but are also at a slightly increased risk for RCC and should be imaged cautiously. Several rare pathological variants of AML exist including AML with epithelial cysts and epithelioid AML, which have distinct imaging characteristics. Classic AML, although benign, can be locally invasive and the rare epithelioid AML can be frankly malignant. The purpose of this review is to highlight the imaging manifestations of 10 uncommon and unusual variants of AML using pathological correlation.

CT in adults: systematic review and meta-analysis of interpretation discrepancy rates.

PURPOSEnTo use meta-analysis to determine the discrepancy rate when interpreting computed tomography (CT) studies performed in adult patients and to determine whether discrepancy rate differs on the basis of body region or level of radiologist training.nnnMATERIALS AND METHODSnMEDLINE and EMBASE were searched from 1946 to June 2012 by using the combination radiology AND (error OR peer review). Two reviewers independently selected studies that met the inclusion criteria and extracted study data. Total and major discrepancy rates were investigated with a random-effects meta-analysis, and subgroups were compared by using the χ(2) Q statistic. Subgroup analyses were performed on the basis of the level of training of the initial radiologist and the body system scanned.nnnRESULTSnFifty-eight studies met the inclusion criteria (388 123 CT examinations). The pooled total discrepancy rate was 7.7% (95% confidence interval [CI]: 5.6%, 10.3%), and the major discrepancy rate was 2.4% (95% CI: 1.7%, 3.2%). The pooled major discrepancy rate was comparable for staff (2.9%; 95% CI: 1.2%, 6.7%) and residents (2.2%; 95% CI: 1.7%, 2.9%) (Q = 0.92, P = .633). The pooled major discrepancy rates for head CT (0.8%; 95% CI: 0.4%, 1.6%) and spine CT (0.7%; 95% CI: 0.2%, 2.7%) were lower than those for chest CT (2.8%; 95% CI: 1.5%, 5.4%) and abdominal CT (2.6%; 95% CI: 1.0%, 6.7%) (Q = 8.28, P = .041). Lack of blinding of the reference radiologist to the initial report was associated with a lower major discrepancy rate (2.0%; 95% CI: 1.4%, 2.7%; 43 studies) than when blinding was present (12.1%; 95% CI: 4.4%, 29.4%; five studies) (Q = 10.65, P = .001).nnnCONCLUSIONnPotentially useful reference ranges were identified in the subgroup analyses on the basis of body region scanned at adult CT. However, considerable heterogeneity that is only partially explained by subgroup analysis signifies that further research is necessary--particularly regarding the question of blinding of the reference radiologist.

Imaging of Acute Abdomen in Pregnancy

The approach to imaging in pregnancy is unique, as it is essential to minimize radiation exposure to the fetus. Ultrasonography and magnetic resonance imaging are the chief modalities for evaluation of the pregnant patient with abdominal pain. Use of computed tomography should not be delayed when there is a need for early diagnosis. This article discusses test selection and underlying reasoning, with a description of common imaging features of different causes of acute abdominal pain in pregnancy. Also discussed are current evidence-based recommendations for the use of iodinated and gadolinium-based contrast agents and the importance of patient counseling.

PET vs Sentinel Lymph Node Biopsy for Staging Melanoma: A Patient Intervention, Comparison, Outcome Analysis

BACKGROUNDnSentinel lymph node biopsy (SLNB) is the gold standard to assess local lymph nodes in patients with melanoma. Positron emission tomography (PET) has been investigated as a noninvasive alternative to SLNB.nnnMETHODSnA systematic literature review was conducted to evaluate PET and PET/computed tomography (CT) compared with SLNB for staging local lymph nodes in patients with intermediate-risk melanoma using the patient, intervention, comparison, outcome (PICO) search strategy. The PubMed, Medline, CancerLit, and Cochrane Library databases were searched for relevant published materials. Guidelines of the American Society of Clinical Oncology (ASCO), and Cancer Care Ontario (CCO) were reviewed, as was the clinical resource, UpToDate. Studies were classified on the basis of levels of evidence delineated by the Oxford Centre for Evidence-Based Medicine.nnnRESULTSnThe PICO search criteria identified 20 studies. There was no level 1 evidence. There were 7 level 2b articles. One review article was consecutive and thus classified as level 3a evidence. Three review articles were retrieved and categorized as level 3b. Three single-center studies were classified as level 3b, and another 3 were classified as level 4. There were two published letters, considered expert opinion and thus classified as level 5 evidence. All identified papers favored SLNB over PET or PET/CT for identifying occult locoregional lymph node metastases.nnnCONCLUSIONnDespite a lack of high-level evidence, the studies concluded that SLNB is superior to PET for local lymph node staging in patients with intermediate-risk melanoma. National guidelines confirmed these conclusions. The likelihood of PET/CT identifying distant metastases in this patient population is equally low because of the small risk for having distant metastases at diagnosis. Further study is required, including larger multicenter prospective trials.

Polypoid lesions of the gallbladder: Disease spectrum with pathologic correlation

Gallbladder polyps are seen on as many as 7% of gallbladder ultrasonographic images. The differential diagnosis for a polypoid gallbladder mass is wide and includes pseudotumors, as well as benign and malignant tumors. Tumefactive sludge may be mistaken for a gallbladder polyp. Pseudotumors include cholesterol polyps, adenomyomatosis, and inflammatory polyps, and they occur in that order of frequency. The most common benign and malignant tumors are adenomas and primary adenocarcinoma, respectively. Polyp size, shape, and other ancillary imaging findings, such as a wide base, wall thickening, and coexistent gallstones, are pertinent items to report when gallbladder polyps are discovered. These findings, as well as patient age and risk factors for gallbladder cancer, guide clinical decision making. Symptomatic polyps without other cause for symptoms, an age over 50 years, and the presence of gallstones are generally considered indications for cholecystectomy. Incidentally noted pedunculated polyps smaller than 5 mm generally do not require follow-up. Polyps that are 6-10 mm require follow-up, although neither the frequency nor the length of follow-up has been established. Polyps that are larger than 10 mm are typically excised, although lower size thresholds for cholecystectomy may be considered for patients with increased risk for gallbladder carcinoma, such as patients with primary sclerosing cholangitis.

Prospective Evaluation of Doppler Sonography to Detect the Twinkling Artifact Versus Unenhanced Computed Tomography for Identifying Urinary Tract Calculi

The twinkling artifact is an emerging tool for identifying urinary tract calculi. The purpose of this prospective study was to evaluate the diagnostic accuracy of the twinkling artifact compared to unenhanced computed tomography in detecting urolithasis.

Internal Hernia after Laparoscopic Roux-en-Y Gastric Bypass: Optimal CT Signs for Diagnosis and Clinical Decision Making

Purpose To evaluate the accuracy of computed tomography (CT) for diagnosis of internal hernia (IH) in patients who have undergone laparoscopic Roux-en-Y gastric bypass and to develop decision tree models to optimize diagnostic accuracy. Materials and Methods This was a retrospective, ethics-approved study of patients who had undergone laparoscopic Roux-en-Y gastric bypass with surgically confirmed IH (n = 76) and without IH (n = 78). Two radiologists independently reviewed each examination for the following previously established CT signs of IH: mesenteric swirl, small-bowel obstruction (SBO), mushroom sign, clustered loops, hurricane eye, small bowel behind the superior mesenteric artery, and right-sided anastomosis. Radiologists also evaluated images for two new signs, superior mesenteric vein (SMV) beaking and criss-cross of the mesenteric vessels. Overall impressions for diagnosis of IH were recorded. Diagnostic accuracy and interobserver agreement were calculated, and multivariate recursive partitioning was performed to evaluate various decision tree models by using the CT signs. Results Accuracy and interobserver agreement regarding the nine CT signs of IH showed considerable variation. The best signs were mesenteric swirl (sensitivity and specificity, 86%-89% and 86%-90%, respectively; κ = 0.74) and SMV beaking (sensitivity and specificity, 80%-88% and 94%-95%, respectively; κ = 0.83). Overall reader impression yielded the highest sensitivity and specificity (96%-99% and 90%-99%, respectively; κ = 0.79). The decision tree model with the highest overall accuracy and sensitivity included mesenteric swirl and SBO, with a diagnostic odds ratio of 154 (95% confidence interval [CI]: 146, 161), sensitivity of 96% (95% CI: 87%, 99%), and specificity of 87% (95% CI: 75%, 93%). The decision tree with the highest specificity included SMV beaking and SBO, with a diagnostic odds ratio of 105 (95% CI: 101, 109), sensitivity of 90% (95% CI: 79%, 95%), and specificity of 92% (95% CI: 83%, 97%). Conclusion The decision tree with the highest accuracy and sensitivity for diagnosis of IH included mesenteric swirl and SBO, the model with the highest specificity included SMV beaking and SBO, and the remaining signs showed lower accuracy and/or poor to fair interobserver agreement. Overall reader impression yielded the highest accuracy for diagnosis of IH, likely because alternate diagnoses not incorporated in the models were considered.