Cystic lesions of the liver in the adult can be classified as developmental, neoplastic, inflammatory, or miscellaneous. Although in some cases it is difficult to distinguish these entities with imaging criteria alone, certain cystic focal liver lesions have classic computed tomographic (CT) and magnetic resonance (MR) imaging features, which are important for the radiologist to understand and recognize. Lesions with such features include simple (bile duct) cyst, autosomal dominant polycystic liver disease, biliary hamartoma, Caroli disease, undifferentiated (embryonal) sarcoma, biliary cystadenoma and cystadenocarcinoma, cystic subtypes of primary liver neoplasms, cystic metastases, pyogenic and amebic abscesses, intrahepatic hydatid cyst, extrapancreatic pseudocyst, and intrahepatic hematoma and biloma. Specific CT and MR imaging findings that are important to recognize are the size of the lesion; the presence and thickness of a wall; the presence of septa, calcifications, or internal nodules; the enhancement pattern; the MR cholangiographic appearance; and the signal intensity spectrum. In addition, access to critical clinical information remains extremely important. The most important clinical parameters defined include age and gender, clinical history, and symptoms. An understanding of the classic CT and MR imaging appearances of cystic focal liver lesions will allow more definitive diagnosis and shorten the diagnostic work-up.

https://pubs.rsna.org/doi/pdf/10.1148/radiographics.21.4.g01jl16895

Cystic Focal Liver Lesions in the Adult: Differential CT and MR Imaging Features

Several recently introduced ‘new’ techniques in computed tomography—iterative reconstruction, gated cardiac CT, multiple-source, and dual-energy CT—actually date back to the early days of CT. We review the historic origins and evolution of these techniques, which may provide some insight into the latest innovations in commercial CT systems.

/pdf/computed-tomography-old-ideas-and-new-technology-3ckzuclq8f.pdf

Computed tomography—old ideas and new technology

The aim of this study was to evaluate the clinical significance of combined fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in patients with lymphoma, and to compare the FDG-PET/CT staging results with those of FDG-PET and CT alone. Twenty-seven patients were studied. Each patient had clinical follow-up for >12 months and entered complete follow-up evaluation. Patient-based evaluation showed a sensitivity of 78% for CT alone, 86% for FDG-PET alone, 93% for CT and FDG-PET read side by side, and 93% for combined FDG-PET/CT imaging. Region-based evaluation showed a sensitivity for regional lymph node involvement of 61%, 78%, 91% and 96% respectively. FDG-PET/CT imaging is superior to CT alone (P=0.02) and has additional benefit over FDG-PET alone due to exact anatomical localisation. We conclude that FDG-PET/CT imaging is accurate in re-staging lymphoma and offers advantages over separate FDG-PET and CT imaging.

FDG-PET/CT in re-staging of patients with lymphoma

BACKGROUND

The accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET; dual-head camera with attenuation correction) and Ga-67 scintigraphy was compared to identify disease sites in patients with Hodgkin disease (HD) and intermediate and high-grade non-Hodgkin lymphoma (NHL) at initial diagnosis or clinical recurrence.



METHODS

Fifty-one contemporaneous FDG-PET and Ga-67 scintigraphies were performed on patients with NHL (35 intermediate grade, 3 high grade) or HD (13 patients). Sites of disease were correlated on a site-by-site basis on FDG-PET and Ga-67 images. Tumor-to-background (T/B) ratios were obtained for both techniques. Discordant FDG-PET and Ga-67 findings were correlated with computed tomography findings or clinical evaluation including repeat FDG-PET scans obtained after therapy.



RESULTS

Fluorodeoxyglucose positron emission tomography was positive at all 158 sites in 51 patients compared with 113 sites in 41 positive studies with Ga-67 scintigraphy (single positron emission computed tomography [SPECT] and/or planar images). In 44 patients who had complete Ga-67 SPECT data on all tumor sites, FDG-PET was positive at 126 sites and Ga-67 SPECT was positive at 81 sites. Ga-67 SPECT failed to demonstrate disease at 45 sites (35.7%). In 10 of 44 patients, Ga-67 SPECT completely failed to detect any disease at 22 of 45 sites (17.5%) and partially identified disease sites at 23 of 45 sites (18.2%) in 11 patients regardless of the tumor site and histology. In these patients, the lesions measured between 0.6 and 14.0 cm by CT. Fluorodeoxyglucose positron emission tomography revealed higher stage disease in 13 patients compared with Ga-67 imaging. Tumor-to-background ratios were statistically different between the two techniques with higher ratios obtained with FDG-PET (P < 0.0001).



CONCLUSIONS

In imaging aggressive lymphoma and HD before therapy, FDG-PET has significantly higher site and patient sensitivity than Ga-67 scintigraphy (100% vs. 71.5% and 100% vs. 80.3%, respectively). The change in disease stage by FDG-PET may result in a change in therapy strategy. Cancer 2002;94:879–88. © 2002 American Cancer Society.



DOI 10.1002/cncr.10336

Comparison of fluorine-18 fluorodeoxyglucose positron emission tomography and Ga-67 scintigraphy in evaluation of lymphoma.

https://www.liver.theclinics.com/article/S1089-3261(05)70162-8/pdf

Mesenchymal Tumors Of The Liver

PURPOSE: To correlate the imaging and pathologic features of undifferentiated (embryonal) sarcoma (UES) and account for the discrepancy between the solid appearance at ultrasound (US) and the almost cystlike appearance at computed tomography (CT) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: The clinical, pathologic, and imaging findings in 28 patients (age range, 3-49 years) with pathologically proved UES were retrospectively reviewed. All patients underwent at least one cross-sectional imaging study to include CT (27 patients), US (21 patients), and MR imaging (six patients). Tumor size, gross morphology (n = 27), histologic features, and proportion of solid and cystlike components were evaluated and correlated to the imaging findings. RESULTS: The mean transverse diameter of the tumors was 14 cm (range, 10-25 cm). At gross examination, the tumors were predominantly solid (mean, 83% of tumor volume), and pathologic and US findings were concordant. Conversely, CT scans showed low attenuatio...

Undifferentiated (embryonal) sarcoma of the liver: pathologic basis of imaging findings in 28 cases.

Computed tomographic (CT) cardiac imaging in vivo has been hampered by motion of the heart during its cardiac cycle A technique of post data-acquisition correlation of the angular projection data using the electrocardiogram as a reference signal is described This method produced seven "stop action" images of the heart and resulted in delineating morphological detail not recognizable on the conventional CT scan

Stop-action cardiac computed tomography.

In order to assess its potential uses in the staging and treatment planning of lymphoma, CT was performed in 27 newly diagnosed, previously untreated patients with Hodgkin's disease or non-Hodgkin's lymphoma; 18 staging laparotomies provided pathologic correlations. CT detected and defined disease in areas not well evaluated by conventional techniques (high para-aortic, mesenteric, splenic hilar nodes). CT interpretation of splenic size and weight correlated well with splenic weight confirmed at pathology. Nodules were identified in several spleens containing foci of lymphoma.

CT-pathologic correlations in Hodgkin's disease and non-Hodgkin's lymphoma.

Atrial myxoma is the commonest of the rare primary heart tumors and one of the few which is curable. Increasing interest in these lesions culminated in a recent symposium on cardiac tumors (8, 9, 14), in which the available literature was summarized in detail. The purpose of this communication is to show previously unreported “tumor vascularity” demonstrated by selective coronary arteriography in a proved case of left atrial myxoma. Case Report A 51-year-old Caucasian male presented with an eight-year history of intermittent dyspnea, orthopnea, ankle edema, and a recent weight gain of 15 lb. Between episodes of failure he was virtually asymptomatic. There was a questionable history of joint symptoms at the age of twelve years, and mild diabetes had been discovered two years previously. Pertinent negative findings included the absence of fever, anemia, or embolic phenomena. Physical examination showed moderate cardiac failure and an apical systolic murmur. The murmur did not alter dramatically with change ...

William H. Marshall

Papers

Undifferentiated (embryonal) sarcoma of the liver: pathologic basis of imaging findings in 28 cases.

Stop-action cardiac computed tomography.

CT-pathologic correlations in Hodgkin's disease and non-Hodgkin's lymphoma.

"Tumor vascularity" in left atrial myxoma demonstrated by selective coronary arteriography.

Computed tomography of the abdomen in the malignant lymphomas.