Patricia J. Mergo

BENIGN LESIONS OF THE LIVER

Although many hepatic lesions can overlap significantly in their imaging appearance, an imaging approach that is based upon identifying the pathologic and functional components of a lesion can aid in distinction from other entities. In this manner, the diagnostic evaluation can be tailored using the appropriate imaging modality for the lesion at hand. An understanding of the benign liver lesions based on the cellular line of origin and subsequent functional components aids in grasping their expected imaging appearance and may aid in their distinction from malignant tumors. Thus, an imaging approach leading to diagnosis of these tumors should be based on this underlying knowledge of the functional components and cells within the lesion to be studied. For lesions with Kupffers cell activity, such as FNA, Tc-99m sulfur colloid scan or MR imaging with SPIO may yield the most diagnostic information. For lesions such as hepatic cysts or angiomyolipoma, the diagnosis is usually not a dilemma. For hemangiomas, the most commonly encountered benign hepatic lesion, distinction from other entities may be readily apparent from the initial CT scan or US examination, or it may require additional evaluation with MR imaging. Finally, for other lesions with many cellular components, such as HCA, the imaging findings may not be specific enough by any modality to preclude tissue diagnosis. In any case, it is important to know the diagnostic accuracy and limitations of the imaging modalities available for assessment of any given benign hepatic mass.

Pediatric liver neoplasms: a radiologic-pathologic correlation.

Abstract. Only 1–2 % of all pediatric tumors occur in the liver. Two thirds of these tumors are malignant and almost all of the tumors cause clinical symptoms due to their mass effects. Besides the poor prognosis in most of the malignant tumors, for further treatment the origin and nature of the neoplasm has to be known. Due to the mostly unimpeded growth into the peritoneal cavity, the origin of the tumors is primarily often unclear and can non-invasively only be determined by advanced imaging techniques. The display of the macro- and microhistological key features of primary pediatric liver neoplasms, including hepatoblastoma (HB), infantile hemangioendothelioma (IHE), mesenchymal hamartoma (MH), undifferentiated (embryonal) sarcoma (UES), and hepatocellular carcinoma (HCC), together with their imaging representation by ultrasound, computed tomography, and magnetic resonance imaging, may deepen the understanding of the underlying pathology and its imaging appearance. Furthermore, in many cases sufficient information may be provided not only to differentiate benign from malignant tumors, but also to guide for adequate treatment.

Mesalamine-related lung disease: clinical, radiographic, and pathologic manifestations.

Lung injury related to mesalamine (5-aminosalicylic acid) has rarely been reported in patients with inflammatory bowel diseases. Patients present with progressive respiratory symptoms and radiographic abnormalities whose genesis may occur from days to years after initiation of therapy. Although pathologic features overlap with other pulmonary disorders, findings of chronic interstitial pneumonia and poorly formed nonnecrotizing granulomas should prompt consideration of mesalamine-related lung disease in a patient receiving this medication. The authors describe the clinical, radiographic, and pathologic manifestations of mesalamine-related lung disease in three patients and review the literature related to this topic.

MRI of the breast in the differential diagnosis of mastitis versus inflammatory carcinoma and follow-up.

PURPOSE Our goal was to evaluate the potential of dynamic MRI in differentiating mastitis and inflammatory breast carcinoma. Furthermore, we evaluated the potential of breast MRI to follow up mastitis patients under antibiotic treatment. METHOD Twenty-one cases of dynamic breast MR (11 mastitis, 10 inflammatory carcinomas) were reviewed. All patients had a history consistent with either mastitis or inflammatory breast carcinoma. The final diagnosis was histologically confirmed. RESULTS Ninety percent of the inflammatory carcinomas were found to enhance > 100% in the first minute compared with 55% for mastitis. There is no significant difference between mastitis and inflammatory carcinoma. CONCLUSION While breast MR cannot currently be used definitively to distinguish inflammatory carcinoma from mastitis, the differences in dynamic enhancement may prove to be useful in follow-up of presumed mastitis in problematic cases. If after biopsy the diagnosis remains unclear, breast MR may help to (a) demonstrate the success of the antibiotic treatment and (b) diagnose coexisting or confounding inflammatory carcinoma.

Multiple hepatorenal angiomyolipomas: Diagnosis with fat suppression, gadolinium-enhanced MRI

Hepatic angiomyolipoma is a rare tumor which may occur as a solitary mass or as an associated finding with tuberous sclerosis. While computed tomography allows identification of the fat component of the lesion, magnetic resonance imaging (MRI) can provide similar information, as well as multiplanar visualization and further characterization of the vascular component of the lesion. MRI utilizing fat suppression and gadolinium enhancement may best provide all of the above information, as is demonstrated in this case report, thus potentially representing the imaging modality of choice.

New formula for quantification of pleural effusions from computed tomography.

The authors develop a method to accurately and easily estimate the volume of pleural effusions with computed tomography (CT). In 15 patients with either simple or loculated pleural effusions (14 right-sided and 11 left-sided), routine helical CT examinations of the thorax were obtained. Two experienced radiologists visually estimated the volume of the effusions. Three-dimensional reconstructions of the pleural effusions were performed from the helical CT examinations, and the volumes of the effusions were calculated. Effusion volumes were also estimated using the formula d2 x l (d = greatest depth of the effusion on a single CT image, l = greatest length of the effusion). The computer calculated the estimated volumes and they were then statistically compared. The coefficient of correlation between the estimation by measurement and calculated volumes of all effusions was 0.908 (p<0.0001) for the right side, and 0.849 for the left side (p<0.002). Excluding the loculated effusions, the coefficient of correlation was 0.969 for the right side and 0.949 for the left side (p<.001). The volume estimation by visual inspection was also correlated to the calculated volumes (0.84 on the left and 0.85 on the right, p<0.008), but resulted in a consistent overestimation by 300 ml to 500 ml. Although pleural effusion volumes can be estimated by visual inspection with good correlation, some overestimation is consistently seen. Use of the formula d2 x l readily enables estimation of pleural effusion volume from CT, from two simple measurements. This formula-based method of volume estimation provides an accurate and easily measured means of estimation that is readily obtained from routine CT of the chest.

IMAGING OF DIFFUSE LIVER DISEASE

Advances in imaging technology and development of liver-specific contrast agents have significantly increased the role of radiology in the detection and characterization of processes diffusely involving the liver. Tailored magnetic resonance imaging (MRI) sequences allow an accurate detection of many storage and metabolic diseases, such as iron overload disorders and steatosis (fatty liver). Faster scanning techniques available with both computed tomography (CT) and MRI provide, by assessing contrast dynamics, sufficient information for the characterization of diffuse neoplastic and vascular disorders. Characteristic changes in attenuation on CT, signal intensity on MRI, and enhancing features can be used to diagnose specific diffuse diseases such as candidiasis, diffuse/multifocal hepatocellular carcinoma, and schistosomiasis. Although an overlap in imaging findings still exists, familiarity with the imaging features of uncommon disorders such as Wilsons disease, amyloidosis, and sarcoidosis may be diagnostic in the proper clinical setting. This review focuses on the current role of imaging in the detection and characterization of diffuse liver disorders. Recent developments that have amplified the role of noninvasive diagnostic evaluation of these conditions are especially highlighted.

Splenic and perisplenic involvement in acute pancreatitis: determination of prevalence and morphologic helical CT features.

Purpose The purpose of this work was to determine the prevalence and morphologic helical CT features of splenic and perisplenic involvement in patients with acute pancreatic inflammatory disease in correlation with the severity of the pancreatitis. Method One hundred fifty-nine contrast-enhanced helical CT scans of 100 consecutive patients with acute pancreatitis were reviewed retrospectively and independently by three observers. CT scans were scored using the CT severity index (CTSI): Pancreatitis was graded as mild (0–2 points), moderate (3–6 points), and severe (7–10 points). Interobserver agreement for both the CTSI and the presence of splenic and perisplenic involvement was calculated (&kgr; statistic). Correlation between the prevalence of complications and the degree of pancreatitis was estimated using the Fisher exact test. Results The severity of pancreatitis was graded as mild (n = 59 scans), moderate (n = 82 scans), and severe (n = 18 scans). Splenic and perisplenic abnormalities detected included perisplenic inflammatory fluid collections (95 scans, 58 patients), narrowing of the splenic vein (35 scans, 25 patients), splenic vein thrombosis (31 scans, 19 patients), splenic infarction (10 scans, 7 patients), and subcapsular hemorrhage (2 scans, 2 patients). No cases of splenic artery pseudoaneurysm formation, intrasplenic venous thrombosis, intrasplenic pseudocysts, or abscesses were detected. The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of abnormalities was 75.5–79.2 and 71.7–100%, respectively. A statistically significant difference between the presence of abnormalities and the severity of pancreatitis was observed (p < 0.001). Conclusion Splenic vein thrombosis (19%) and splenic infarction (7%) are relatively common CT findings in association with acute pancreatitis. The CTSI proves to be accurate in predicting these complications as there is a statistically significant correlation between the prevalence of these complications and the severity of pancreatitis.

Tunnel placement in anterior cruciate ligament reconstruction: MRI analysis as an important factor in the radiological report.

Abstract Objective. Correct placement of tunnels for anterior cruciate ligament (ACL) reconstruction is of prime importance for the clinical outcome of the patient. In this study, the possibility of using MRI to document tunnel placement and provide a more comprehensive report following ACL reconstruction was explored at no additional cost in patients scheduled for routine knee MRI. Design and patients. One year after ACL reconstruction, 45 patients underwent clinical examination (IKCD score), radiographic examination, and MRI using a 1.5-T unit. Results. Twenty patients with good tibial and femoral attachment results were found at clinical examination to have a stable knee joint with a full range of motion. In 25 patients with suboptimal placements, examination showed either a stable knee with a decreased range of motion or instability with a normal range of motion. Conclusion. Patients’ clinical outcome, and the radiographic and MRI findings, correlated closely with the quality of operative tunnel placement. A record of this finding is important for completeness of the radiological report. Furthermore the MRI findings can be used to improve the surgical quality of tunnel placement. Because tunnel placement can be shown adequately with radiography, however, MRI cannot be justified for this reason alone, so such assessment is advised only when MRI is needed to show all postoperative features.

Renal and perirenal space involvement in acute pancreatitis: spiral CT findings

AbstractBackground: This study was conducted to estimate the prevalence and morphologic computed tomographic (CT) features of renal and perirenal space abnormalities in acute pancreatitis in correlation with the severity of pancreatitis. Methods: One hundred fifty-nine contrast-enhanced CT scans of 100 consecutive patients with acute pancreatitis were retrospectively and independently reviewed by three observers. All CT images were obtained using contrast-enhanced helical CT (collimation width = 5 mm, table increment = 7 mm/s, reconstruction interval = 5 mm, scan delay time = 30–50 s). Additional maximized images (field of view = 260 mm) of the perirenal space were available for review. All CT scans were scored with the CT Severity Score Index: pancreatitis was graded as mild (0–2 points), moderate (3–6 points), and severe (7–10 points). Interobserver agreement for both the severity score and the presence of renal and perirenal involvement was calculated. Correlation between the prevalence of complications and the degree of pancreatitis was estimated. Results: CT scans were graded as mild (n= 59), moderate (n= 82), and severe (n= 18). Abnormalities detected included perirenal stranding (n= 37 patients, 26 bilateral), perirenal fluid collections (n= 10 patients, one bilateral), ureteral encasement (n= 2 patients), renal vein thrombosis (n= 1 patient), and renal parenchymal abnormalities (n= 1 patient). The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of abnormalities was 75.5–79.2% and 59.8–100%, respectively. Except for stranding of the perirenal fat, no statistically significant differences between the presence of abnormalities and the severity of pancreatitis (moderate or severe) was observed with Fishers exact test. Also, no preferential left-sided localization of complications was observed. Conclusions: The incidence of renal and perirenal complications from acute pancreatitis is higher than previously estimated (7%). We found no significant correlation between the prevalence of major complications and the severity of pancreatitis. These findings are important because these complications may have an impact on therapeutic strategy and can affect prognosis.