Faculty Bibliography

BACKGROUND: Hepatocellular carcinoma (HCC) is routinely graded histopathologically using a modified Edmondson system (ES). The cytologic grading of HCC has been used predominantly as an adjunct in differential diagnoses (i.e., to help distinguish HCC from other tumors as well as nonneoplastic lesions). However, there are unanswered questions regarding the reliability of the cytologic grading of HCC and its correlation with histologic follow-up. METHODS: A total of 106 cases of HCC were identified in the authors' cytopathology files from 1977 to the present. Of these cases, 64 had either a core needle or excisional biopsy sample that was judged to be adequate for histologic grading. From each case smears were graded independently in a blinded fashion by two cytopathologists, and tissue slides were graded by a liver pathologist. The cytopathologists' grading was then adjudicated by considering the histologic diagnosis as the "truth standard". Finally, after the scores were calculated, a statistical analysis was performed to ascertain the accuracy of the cytopathologic grading. RESULTS: The sensitivity for accurate grading was found to be highest for well differentiated (WD) lesions; the specificity was found to be highest for poorly differentiated (PD) HCC for both cytopathologists. Interobserver agreement was highest for WD HCC. WD HCC displayed cohesive fragments, often associated with characteristic vascular/endothelial patterns. In addition, moderately differentiated (MD) HCC demonstrated numerous single cells and atypical naked nuclei, usually with prominent nucleoli. PD HCC displayed loose nests and three-dimensional fragments (often gland-like), pleomorphism, macronucleoli, and focal necrosis. CONCLUSIONS: In the authors' experience, the three-tier cytologic grading of HCC was found to be only moderately accurate. The accuracy of cytologic grading was reported to be high for WD/PD HCC and low for MD HCC. The architectural criteria appear to be more useful for WD HCC, whereas marked cellular pleomorphism is specific for PD HCC. The authors propose that a two-tier grading system may be more useful, given the recent studies of HCC recurrence.

Multi-detector row helical computed tomography (CT) offers considerable advantages in evaluation of the urinary tract. It has the potential to become the single imaging modality used for comprehensive evaluation and treatment planning of most conditions affecting the kidneys and urinary tract, making conventional diagnostic techniques such as intravenous urography and angiography nearly obsolete. This article illustrates important selected applications of multidetector CT in the evaluation of benign conditions of the kidneys and upper urinary tract, including evaluation of the renal arterial and venous anatomy in preparation for surgery, diagnosis of renal artery stenosis and aneurysms, assessment of the renal veins, imaging of inflammatory and infectious renal diseases and evaluation of selected benign pathologic processes of the urinary tract.

Computed tomography (CT) remains the optimal imaging modality for diagnosing tumors in the mesentery. Although primary neoplasms arising from the mesenchymal tissues of the mesentery are rare, the small bowel mesentery is a major avenue for the dissemination of tumor within the peritoneal cavity. Tumors spread to the mesentery by four major routes: (a) direct extension, commonly seen with carcinoid tumor of the small intestine as well as intraabdominal cancers such as pancreatic and colon cancer; (b) lymphatic dissemination of lymphoma and some epithelial malignancies; (c) hematogenic spread resulting in embolic metastases to the small intestinal wall, usually seen in melanoma and breast cancer; and (d) seeding through the peritoneum from ovarian and gastrointestinal malignancies as well as some lymphomas. Although percutaneous imaging-guided or surgical biopsy is often necessary to guide management, analysis of CT features along with the clinical history may be useful in differentiating mesenteric tumors from infectious, inflammatory, or vascular processes affecting the mesentery. The article presents the characteristic appearances of primary and secondary mesenteric neoplasms at CT and offers a rational approach to the differential diagnosis of mesenteric masses depicted at CT.

Multidetector row CT (MDCT) is the latest advancement in CT technology. The use of multiple detector rows allows faster scanning and thinner collimation. These improvements allow routine scans to be performed faster with higher z-axis resolution. New applications can also be developed using this new technology. To fully appreciate the potential of these new MDCT scanners, it is important for the radiologist to be familiar with the scanner design and capabilities. This article reviews the basic principles of MDCT scanners. Scanner/detector design, beam collimation/slice thickness, radiation dose, data manipulation, and display are discussed.

In this article, the radiological manifestations of a variety of uncommon tumors of the pancreas are illustrated, with emphasis placed on their appearance at helical CT. Islet cell tumors, because of their vascularity, typically present as masses that are hyperattenuating to the normal pancreas at dual-phase helical CT. Lymphomas appear as hypoattenuating focal lesions or can diffusely infiltrate the gland. Absence of biliary tree dilatation, despite the presence of a bulky tumor, or associated extensive retroperitoneal adenopathy should offer clues to the diagnosis. Pancreatic metastases are usually seen in patients with advanced cancers, although isolated metastases from renal cell carcinoma can occurs years after the original tumor; such patients may benefit from surgical resection. Finally, the appearance of some rare neoplasms of mesenchymal origin is discussed.

PURPOSE: To use radiologic-histopathologic correlation in an animal model to distinguish normal postoperative findings from evidence of residual tumor after cryoablation of malignant hepatic tumors. MATERIALS AND METHODS: Hepatic cryoablation was performed in 12 rabbits with VX2 tumors and in two healthy rabbits. Nonenhanced and dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging and power and color Doppler flow ultrasonography (US) were performed 7-8 days after cryoablation. Histopathologic findings were correlated with imaging findings. RESULTS: Twenty tumors of 5-20 mm (mean, 10 mm) and seven areas of normal liver were treated with cryolesions of 11-21 mm (mean, 15 mm). All cryolesions exhibited arterial phase rim enhancement at CT and MR imaging, and 13 (57%) of 23 lesions demonstrated peripheral flow at US because of granulation tissue. There was macroscopic recurrence in 15 (75%) of 20 treated tumors; 14 (93%) appeared as peripheral nodularity with low-grade enhancement. Necrotic tissue did not enhance. Intact vessels extended up to 6 mm inside cryolesion margins and caused focal internal enhancement and Doppler flow. Areas of high signal intensity on T2-weighted MR images correlated with liquefaction necrosis, granulation tissue, and tumor. CONCLUSION: In this animal model, recurrent tumor typically appeared as focal nodules at the cryolesion periphery. Rim and central foci of enhancement, Doppler flow, and increased signal intensity on T2-weighted MR images can be normal findings after hepatic cryoablation.

PURPOSE: To assess the feasibility of using a three-dimensional (3D) endorectal transducer at ultrasonography (US) in the prostate gland in a clinical setting. MATERIALS AND METHODS: Sixteen patients underwent 3D imaging of the prostate gland with a 3D endorectal probe following conventional two-dimensional (2D) US and prior to prostatic biopsy. Image acquisition was performed as a volume of data with nearly immediate reconstruction and simultaneous display of sectional anatomy in three orthogonal planes--sagittal plane, transverse or coronal plane, or any arbitrary oblique plane. Images were evaluated for presence of focal lesions, glandular volume, visualization of lateral and anterior portions of the gland, and extraglandular extension of tumor. RESULTS: Three-dimensional US allowed better visualization of the gland and focal lesions, especially on the coronally reconstructed images, which were judged superior to the sagittally or transversely reconstructed images for interpretation in 50% of the patients. Prostatic volumes obtained from 3D US were consistently smaller than volumes obtained from 2D US (20% difference, P = .006). Three-dimensional US was superior to 2D US in depicting tumor presence (nine of 10 right hemispheres, three of eight left hemispheres) and extraglandular extent of disease (three of five hemispheres). CONCLUSION: Three-dimensional endorectal prostatic US appears to be clinically feasible and easy to perform. Added anatomic information from the coronal plane may allow better depiction of tumors and extraglandular spread than is possible with current 2D techniques.