Jon W. Meilstrup

Renal cystic diseases

Abstract Renal cystic disease comprises a mixed group of heritable, developmental, and acquired disorders. Because of their diverse etiology, histology, and clinical presentation, no single scheme of classification has gained acceptance. Conditions include autosomal dominant polycystic kidney disease, acquired renal cystic disease, medullary sponge kidney, autosomal recessive polycystic kidney disease, multicystic dysplastic kidney, medullary cystic disease, tuberous sclerosis, cysts of the renal sinus, and von Hippel-Lindaus disease. An awareness of the pathology of each cystic disease is helpful in the understanding of the corresponding radiological images. Imaging techniques used in evaluating renal cystic disease include intravenous urography, sonography, CT, MRI, nuclear medicine, and renal angiography. Many types of cystic disease show similar imaging features. Meticulous attention to subtle radiological findings is therefore essential for reaching a correct diagnosis. Imaging features requiring analysis include whether the cysts are unilateral or bilateral, renal size and functional status, cyst distribution in the kidneys, and the presence of hemorrhagic and calcified renal cysts, solid renal masses, renal sinus cysts, and cysts in adjacent organs. Radiological findings should be carefully correlated with clinical features such as patient age, family history, symptoms, physical findings, and renal functional status before a diagnosis is attempted.

CURRENT CONCEPTS AND CONTROVERSIES IN IMAGING OF RENAL CYSTIC DISEASES

Renal cystic disease compromises a diverse group of inherited and acquired entities. This article reviews the clinical, pathologic, and radiologic findings of eight renal cystic diseases. For each entity, the current concepts of pathogenesis and pathophysiology are discussed. When appropriate, controversies concerning terminology, management, and malignant potentials are addressed. Renal cystic diseases that are discussed include autosomal dominant and autosomal recessive polycystic kidney disease, medullary sponge kidney, medullary cystic disease, multicystic, dysplastic kidney, von Hippel-Lindau disease, acquired cystic kidney disease, and tuberous sclerosis.

The quality of 3D reconstructions from 1.0 and 1.5 pitch helical and conventional CT.

PURPOSE CT data are commonly used to create 3D images. For this purpose, thin and overlapped slices are desirable. Helical (spiral) CT offers the ability to adjust the slice reconstruction interval from 0 to 100%. However, its use in 1.0 and 1.5 pitch helical CT and 3D imaging, especially with respect to surface detail, is relatively untested. METHODS Ten objects selected for their varying size, shape, and density were scanned (fourth generation Picker PQ2000) by contiguous 2,4 and 8 mm conventional and helical sequences. The latter were obtained with a pitch of both 1.0 and 1.5 and were reconstructed into a 3D image with 0-75% overlapping of the reconstructed slices. Each of the 24 different sequences per scanned object was reconstructed into identical sets (projections) of 3D images displayed on color film. The 24 3D image sets for each object were submitted to six blinded radiologists who separately ranked them from best to worst. RESULTS 3D reconstructions obtained from CT scans with a thinner slice thickness, half-field (15 cm FOV), and helical technique were rated as statistically superior. The 1.0 and 1.5 helical sequences obtained with a 4 or 8 mm slice thickness scored statistically better than 3D reconstructions from equivalent conventional scans. Overlapping of the reconstructed helical slices by 25-75% generally improved the quality of the 3D reconstruction. CONCLUSION Helical CT with either a 1.0 or a 1.5 pitch offers the ability to obtain higher quality 3D reconstructions than from comparable conventional CT scans.

Appendiceal imaging: Which test is best?

Radiologic imaging has been clearly shown to be useful for the evaluation of patients clinically suspected of having appendicitis with CT and ultrasound being the most frequently recommended modalities. However, controversy still exists as to which modality is the technique of choice for appendiceal imaging. Our experience has led us to conclude that a standard helical abdominopelvic CT is the initial test of choice for the evaluation of the adult patient suspected of having acute appendicitis. Focused appendiceal CT with colonic contrast is then utilized as a problem solving technique for equivocal cases after this initial assessment.

Prenatal sonographic appearance of asymmetric craniosynostosis: a case report.

Craniosynostosis is the premature fusion of one or more cranial sutures.1.2 Depending on the sutures involved, a characteristic skull deformity usually results.J Premature closure of a suture restricts expansion of the calvarium adjacent to the suture. Because adjacent areas of the skull overexpand to accommodate the growing brain, a lobulated appearance can result. In our patient prenatal sonography demonstrated an unusual asymmetric multilobulat· ed skull caused by craniosynostosis resulting from premature synostosis of a coronal and a sagittal suture. Prenatal diagnosis of the symmetric trilobu· Ia ted skull has been previously reported.4-10 We present here the sonographic appearance of a more unusual asymmetric craniosynostosis.

Multiplanar image reconstruction and 3D imaging using a musculoskeletal phantom: conventional versus helical CT.

PURPOSE Our goal was to perform a detailed comparison of the relative performances of helical CT (pitches 1.0, 1.5, and 2.0) and conventional (overlapped and nonoverlapped) CT in detailed 3D and MPR musculoskeletal imaging. METHOD A specially designed bone fragment phantom was imaged with multiple slice thicknesses using conventional (overlapped and nonoverlapped) and helical (varying pitch and slice index) CT. Studies were randomized, blinded, and graded using predetermined criteria by 10 radiologists. Statistical analysis included an assessment of raw image scores, a separate testing using duplicate copies of the conventional images as gold standards, and a multivariate model based upon the results of both scoring systems. RESULTS When assessing raw scores of the images, conventional scans were consistently scored more favorably than helical studies. Decreasing the slice index improved conventional CT studies and helical studies with a pitch of 1.0, but showed no effect on helical studies with a pitch of > 1.0. When using the conventional studies as gold standards, the helical studies were consistently graded as poorer than conventional overlapped and nonoverlapped studies. CONCLUSION For detailed musculoskeletal 3D and MPR work, helical CT may not adequately compare with conventional CT and offers no discernible advantage, particularly for pitches of > 1.0.