Septa of Bertin: a sonographic pseudotumor

Sonographic Evaluation of Renal Appearance in 665 Adult Volunteers

The purpose of this study was to investigate the sonographic appearance of the normal adult kidney. Parenchymal echogenicity, pyramid visibility, and transverse pelvis diameter of the kidneys were prospectively determined in an age- and sex-stratified random sample of 665 volunteers 30, 40, 50, 60, and 70 years old. Furthermore, incidences of kidney stones and split sinus echo were determined. The relation between obesity and above-mentioned parameters was evaluated. In the 30-year-old age group the right kidney was isoechoic as compared to the liver in 1/3, and had clearly or faintly visible pyramids in 2/3 of the cases. These rates decreased gradually with increasing age. Transverse diameter of renal pelvis ≥10 mm was observed in 13% of participants. Renal stones were observed in 2.1%. The incidence of split sinus echo was 3.6%. Obese participants showed lower incidences of isoechogenicity, pyramid visibility, pelvic ectasia, and split sinus echo. Isoechoic parenchyma, clearly visible pyramids, and transverse pelvis diameter ≥10 mm are not uncommon sonographic findings in normal adult kidneys and should not be used as indicators of renal pathology.

Some misconceptions and pitfalls in ultrasonography

There are many misconceptions in the field of ultrasonography. Some are because of poor understanding of anatomy and/or embryological or developmental features of certain organs, which have prevailed over the course of the centuries since the discovery of these entities (e.g., column of Bertin and hypertrophic column of Bertin). Some misconceptions derived from misinterpretation (e.g., double decidual sac sign) or inadequate observation of ultrasonographic findings. (e.g., hyperechoic stroma in polycystic ovarian syndrome).

Mass effect in the renal sinus: an anatomic classification

Before the advent of modern imaging techniques, pathologic processes in the renal sinus were diagnostic enigmas. Many of the conditions create nonspecific deformities of the contrast-filled collecting system. In the past, the discovery of these abnormalities often led to unnecessary exploration. Modern imaging techniques usually allow a specific diagnosis to be made, but because a number of the pathologic conditions affecting the renal sinus have similar appearances on a single type of imaging study, complete delineation may require correlation of a number of diagnostic techniques. An understanding of the normal sinus anatomy allows classification of pathologic processes that occur in this region and ensures an orderly imaging investigation. The anatomic classification is based on the structure from which the mass arises. The source of the mass may be any structure within the renal sinus (intrinsic), the enveloping renal parenchymal (adjacent), or a source outside the kidney itself with subsequent sinus involvement (extrinsic). This classification will be used to review a number of pathologic processes that occur in the renal sinus and pertinent imaging features.

Sonographic evaluation of renal masses

Basic technique of evaluating renal mass lesions is presented. The analytic criteria of separating cystic from solid lesions are reviewed along with the differential points of the intermediate mass lesion that does not meet the classical hallmark of a simple cyst. Experience has shown that sonography could be the first evaluation step in a renal mass since it is not invasive, does not employ ionizing radiation, and is cost effective.

Multiple-section radionuclide tomography of the kidney: a clinical evaluation

The clinical utility of radionuclide emission tomography of the kidney in comparison with conventional gamma-camera imaging has been assessed from scans of 60 patients suspected of having space-occupying lesions of the kidney. Nineteen patients had renal tumour, 17 had cysts and seven had renal pseudotumours; the remainder had no lesion. Objective trials using four observers showed only a slight, statistically insignificant advantage from the addition of tomographic sections to conventional images. However, in several individual cases tomography had aided diagnosis, particularly in obese patients, when an alternative non-invasive investigation (ultrasonography) was inconclusive. In seven patients a positive diagnosis of renal pseudotumour was made possible by tomography; definite identification of ectopic functioning cortical tissue at the location of a mass suspected after urography was considered to be a distinct diagnostic advantage gained from emission tomography of the kidney.

The ultrasonic appearances of the septa of Bertin in children

The ultrasonic appearances of the septa of Bertin are described in relation to eight children. These septa may be of varying echogenicity from the remaining cortex and may lead to a misdiagnosis of a true pathological lesion. In our series, two children had an initial suspicion of an abdominal mass; one an intrarenal neoplasm and the other an intrarenal haematoma. It is of importance to recognise this normal variation to avoid misdiagnosis of a pathological mass and to avoid further unnecessary investigation.