The lobar structure of the kidney

Classifying Renal Pyelocaliceal System: A Complete Literature Overview of All Existing Classification Approaches

Introduction: Our comprehension of the actual diversity of kidney pyelocaliceal system (PCS) is lacking and many crucial features have been overlooked in the existing literature on this subject. The purpose of this review is to provide a concise summary of the current understanding of the structure of the pelvicalyceal system, considering both anatomical and surgical perspectives, as well as to highlight any limitations or inconsistencies in these approaches. Material and Methods: A full review of all the literature on the anatomical and surgical methods used to classify pelvicalyceal system was conducted in several databases in August 2024. This included all the articles that talked about classifications for the whole pelvicalyceal system, minor calyces, and morphometric measurements within the pelvicalyceal system. Results: Despite over a century of studying this anatomical zone and numerous approaches, some classifications still rely on pelvic branching or the division site related to the renal sinus. However, no single classification has incorporated both aspects. In addition, despite the consensus regarding the number of minor calyces, there are many approaches to determining their orientation. Finally, researchers have described a sufficient number of morphometric measurements within the pelvicalyceal system, considering their prognostic value before endourological interventions and their correlation with individual patterns of the structure of pelvicalyceal system. However, these measurements often lead to contradictions in interpreting the anatomical favorability of the same pelvicalyceal system using different approaches. Conclusion: Despite the numerous approaches to identify pelvicalyceal system from both morphological and surgical perspectives, there are significant gaps in our understanding of the real anatomy of the renal cavity that, even after more than a century, remain unanswered. There needs to be more correlation of anatomy with modern minimally invasive clinical interventions for stone disease.

Classification and clinical significance of the posterior group of renal calyces

To study the anatomical orientation of the posterior group of calyces based on reconstructed images of computerized tomography urography (CTU) and provide a novel classification with its clinical significance. Clinical data of a total of 1321 patients, who underwent CTU examination in our hospital were retrospectively analyzed. Among these, a total of 2642 3-dimensional reconstructed images of CTU scans were considered in this study. Based on the morphology of the renal calyces and the influence on the establishment of surgical access, the posterior group renal calyces are classified into 3 major types including pot-belly type, classically branched and elongated branched. The classically branched type is further classified into 3 sub-types: a, b and c, based on the association of minor calyces of the posterior group to the major calyces. Type a is derived from 1 group of major calyces only, type b is derived from 2 groups of major calyces simultaneously, and type c is derived from 3 groups of major calyces simultaneously. Statistical findings revealed that all kidneys possess posterior group calyces. The percentage of occurrence of pot-belly type, classically branched and elongated branched is 8.06%, 73.13%, and 18.81%, respectively. The anatomical typing of the classical branching type occurred in 19.36%, 68.17%, and 12.47% for types a, b, and c, respectively. In this study, the posterior group calyces were found to be present across all patients. The posterior group calyces were highest in the classical branching type, of which anatomical typing was highest in type b. The typing of the posterior group of calyces could provide an anatomical basis for percutaneous nephrolithotomy (PCNL) puncture from the posterior group.

Renal lobar dysmorphism: a potential mimic of renal malignancy

A renal pseudotumour is any apparent renal mass that simulates a tumour on radiological imaging but is composed of normal tissue. Renal pseudotumours may be inflammatory, vascular, postsurgical or congenital. We report a case of renal lobar dysmorphism (RLD) of the kidney, a congenital renal pseudotumour. A 45-year-old man presented with scrotal swelling. Testicular ultrasound showed an epididymal cyst. Renal ultrasound showed a right solid renal apparent mass of 2.4 cm in diameter. Triphasic renal CT showed this was consistent with RLD. Intravenous urography confirmed a central calyx within the dysmorphic lobe. RLD is a rare congenital normal anatomical variant, which can appear as a renal pseudotumour. No further investigation or intervention is necessary. We present the radiological findings of RLD and review the literature.

Impact of Anterior Kidney Calyx Involvement of Complex Stones on Outcomes for Patients Undergoing Percutaneous Nephrolithotomy

INTRODUCTION

A number of factors that can impact the outcomes of percutaneous nephrolithotomy (PCNL) procedures have previously been investigated. Complex stones that extend to the anterior calyx could affect the success and complication rates of PCNL.

OBJECTIVE

We analyzed the effect of anterior calyx involvement on the outcomes of patients with complex stones treated with PCNL.

METHODS

A total of 132 consecutive patients who underwent PCNL due to complex stones (multiple, partial staghorn, or staghorn stones) between 2015 and 2017 were enrolled in this study. They were stratified into two groups based on whether the stone extended to the anterior calyx (group 1, n = 45) or not (group 2, n = 87). The stratification was achieved through contrast-enhanced computerized tomography (CT). Demographics, laboratory tests, and peri- and postoperative findings (operation and fluoroscopy duration, hospital stay, utilization of flexible instruments, access numbers, total blood count change, stone-free rate [SFR], and complications) were compared between the groups. The SFR was evaluated by plain kidney-ureter-bladder radiography or CT.

RESULTS

The demographics, operation and fluoroscopy duration, access number, and hospital stay were similar between the groups (p < 0.05). A higher drop in the hemoglobin level in group 1 was identified (group 1 [2.14 ± 1.49 g/dL] vs. group 2 [1.43 ± 1.31 g/dL]) (p = 0.006). The SFR among the patients with extension to the anterior calyx was 60%, compared to 77% among the patients with no extension to the anterior calyx (p = 0.041). Flexible instruments were utilized in 60% of the patients of group 1, which was a higher rate than for group 2 (36%) (p = 0.007). Complication rates were similar in the two groups according to the Clavien-Dindo classification (p > 0.05).

CONCLUSIONS

Our study demonstrated that complicated stones with extension to the anterior calyx are more challenging than cases without extension to the anterior calyx. This was noted by a lower SFR, a more prominent drop in total blood count, and more frequent utilization of flexible scopes.

Pictorial review: Renal ultrasound

Ultrasound (US) is the first-line imaging modality for evaluating azotemic patients for urinary obstruction and renal size. US is also valuable for distinguishing congenital variants and simple cystic lesions from renal masses. Doppler US is effective in detection of renal calculi and evaluation of vascular pathology. Unfortunately, renal US is limited in distinguishing causes of medical renal disease. The kidneys have a complex internal architecture with a highly variable appearance on US. This article illustrates non-neoplastic renal conditions, including normal and embryological variants, parenchymal, cystic, and vascular diseases. Renal infections, calcifications, and trauma and fluid collections are also discussed, with an emphasis on distinguishing US features and pathophysiology.

Persistent fetal lobulation of kidney mimicking renal tumour

Renal pseudotumour is a term coined to describe conditions of renal anatomic variants that simulate focal renal pathology like a tumour on ultrasonography. These include persistent fetal lobulation, hypertrophy of Bertin columns and dromedary humps. We report a case of a 30-year-old nulliparous woman who was managed in gynaecology clinic for menorrhagia and was subsequently referred to us for management of recurrent urinary tract infections. The clinical examination was normal and on ultrasound scan, she was found to have multiple enlarged heterogeneous solid masses in both kidneys with significantly increased vascularity, suspicious for neoplastic lesions. She subsequently underwent a CT urogram and her case was discussed in uro-radiology meeting where a diagnosis of persistent fetal lobulation was made excluding other diagnoses. She was managed conservatively. We also present grey scale and Doppler ultrasound and CT urogram findings of this condition along with the literature review.

Use of Volume Rendered, Maximum Intensity Projection Images to Assess Whether the Medial Calyx Synonymous with the Posterior Calyx

INTRODUCTION

This paper attempts to verify the anatomical veracity of the belief that in order to enter into a posterior calyx one must aim for the medial calyx during a percutaneous nephrolithotomy (PCNL).

METHODS

Volume rendered and maximum intensity projection reconstructions of normal pelvicalyceal systems were assessed in various rotational planes. An experienced urologist decided the appropriate access for PCNL in the upper, interpole and lower calyx on each side. The selected calyx was then viewed on anteroposterior sections to decide whether they were projecting laterally or medially.

RESULTS

Of the 508 calyces studied, the posterior calyx was projecting laterally in 72% and medially in 28%. In the upper calyx, the posterior calyx was projecting laterally in a majority of cases, 94% on the right and 89% on the left. In the right lower calyx, the posterior calyx was pointing laterally in 86%, whereas the distribution on the left was 64%.

CONCLUSION

Our results refute the belief that the medial calyx is always synonymous with the lateral calyx.

Management of anterior caliceal stones >15 mm

Anterior caliceal stones represent a challenge to endourologist to select the best modality of management with the least morbidity. To study different treatment modalities of management of anterior caliceal stones >15 mm. It is an observational prospective study of patients with anterior caliceal stones more than 15 mm. Inclusion criteria were patients with isolated anterior caliceal stones, or branched anterior caliceal stones with posterior caliceal extension. Patients were evaluated using non-contrast CT preoperatively. They were divided into three groups: group 1 underwent PCNL through posterior caliceal puncture in cases with wide anterior calyx infundibulum or obtuse infundibulopelvic pelvic, group 2 underwent PCNL through anterior caliceal access in cases with narrow infundibulum or acute infundibulopelvic angel and group 3 underwent flexible ureteroscopy and laser lithotripsy. Intraoperative and postoperative findings were recorded and compared. Eighty eight patients were included in this study, Group 1 (44 patients) group 2 (28 patients), and group 3 (16 patients). Operative time was not significantly different across the three groups (68 ± 11.5, 72 ± 9 and 74 ± 11 min in group 1, 2 and 3, respectively, P = 0.053). Fluoroscopy time was significantly shorter for group 3 (2 ± 0.5 m, P = 0.0001) compared to group 1 and 2 (5.6 ± 4.6 and 4.5 ± 1.4 min), respectively. There were no significant differences in stone-free rates after initial treatment between the three groups; 84, 82, and 69 %, in groups 1, 2 and 3, respectively (P = 0.4). Postoperative hemoglobin drop was noted to be highest for group 2 and lowest for group 3 which was significantly different (1.7 ± 0.8, 2.2 ± 1.1, and 0.3 ± 0.3 g/dl, for patients in groups 1, 2 and 3 respectively, P = 0.0001). Group 2 showed the highest post-operative complication rate (21 %) in comparison to group 1 (11 %) and group 3 (6 %), however, differences were not statistically significant (P = 0.3). PCNL through posterior or anterior caliceal puncture is an excellent modality to treat anterior caliceal stones with high stone clearance rate. Despite the higher chance of bleeding with anterior caliceal puncture, it is still inevitably needed in difficult anterior caliceal stones with unfavorable anatomy. RIRS is a good alternative to PCNL with the advantage of less radiation exposure and less bleeding.

Renal calyceal anatomy characterization with 3-dimensional in vivo computerized tomography imaging

PURPOSE

Calyceal selection for percutaneous renal access is critical for safe, effective performance of percutaneous nephrolithotomy. Available anatomical evidence is contradictory and incomplete. We present detailed renal calyceal anatomy obtained from in vivo 3-dimentional computerized tomography renderings.

MATERIALS AND METHODS

A total of 60 computerized tomography urograms were randomly selected. The renal collecting system was isolated and 3-dimensional renderings were constructed. The primary plane of each calyceal group of 100 kidneys was determined. A coronal maximum intensity projection was used for simulated percutaneous access. The most inferior calyx was designated calyx 1. Moving superiorly, the subsequent calyces were designated calyx 2 and, when present, calyx 3. The surface rendering was rotated to assess the primary plane of the calyceal group and the orientation of the select calyx.

RESULTS

The primary plane of the upper pole calyceal group was mediolateral in 95% of kidneys and the primary plane of the lower pole calyceal group was anteroposterior in 95%. Calyx 2 was chosen in 90 of 97 simulations and it was appropriate in 92%. Calyx 3 was chosen in 7 simulations but it was appropriate in only 57%. Calyx 1 was not selected in any simulation and it was anteriorly oriented in 75% of kidneys.

CONCLUSIONS

Appropriate lower pole calyceal access can be reliably accomplished with an understanding of the anatomical relationship between individual calyceal orientation and the primary plane of the calyceal group. Calyx 2 is most often appropriate for accessing the anteroposterior primary plane of the lower pole. Calyx 1 is most commonly oriented anterior.

Anatomic and physiologic considerations in ureteroscopy

The successful and safe implementation of ureteroscopic techniques depends on considerations of anatomy and physiology. Combining knowledge of the drainage system of the kidney with its vascular supply, predictive patterns of incisions can be applied within the collecting system to safely avoid vascular injury. In addition, awareness of the variation in normal and pathologic anatomy and physiology is key to effective interventions. An appreciation of the impact of ureteroscopy on normal anatomy and physiology can prevent complications and promote improved therapeutic outcomes.

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).

CT analysis of caliceal anatomy in the supine and prone positions

PURPOSE

To assess the effect of patient positioning on the position of the kidneys and their consequent projection onto plain radiographs, thus ascertaining the need for special preoperative imaging.

PATIENTS AND METHODS

Fourteen patients were studied by obtaining fine (5-mm)-cut contrast-enhanced CT scans in the pyelogram phase in both the supine and prone position. The orientation of the kidneys relative to the midsagittal plane of the body and the orientation of the anterior and posterior calices relative to the axis of the kidney were measured from hardcopy images. Comparison was made between prone and supine positions for left and right kidneys separately, as well as overall.

RESULTS

The position of the patient had a small effect on the orientation of the kidneys, with the mean angle changing from 56.6 degrees when supine to 61.6 degrees when prone (p < 0.05). However, no significant change in caliceal orientation or the relative projection of the anterior and posterior calices occurred as a result.

CONCLUSION

There is no need to carry out special preoperative imaging in the operative or prone position.

Kidneys of the killerwhale and significance of reniculism

BACKGROUND

The kidneys of all Cetacea are composed of many small relatively independent kidneys (renicules) containing considerable interrenicular tissue. Although reniculism is not entirely confined to the Cetacea, it is desirable to consider the possible advantage of reniculism to mammals of gigantic size. The kidneys of the killerwhale, Orcinus orca, are compared from this standpoint to the kidneys of diverse mammals.

METHODS

The specific renal parenchymal mass, glomerular counts, glomerular size, and specific glomerular mass of the killerwhale are measured and compared quantitatively (statistically) with similar data from numerous diverse mammals. Simultaneously, a method is described for enumerating the renicules of a cetacean kidney.

RESULTS

Specific parenchymal mass of a killerwhale adult's two kidneys (0.33%) is close to the expected value for mammals of its adult body mass (2,087 kg). The diameter of the adult's glomerular capsules (153 microm) is strikingly less than that expected from its body mass (regression equation and graph for mammals in general). However, the number of glomeruli per kidney (approximately 100 x 10[6]) is markedly greater than that for mammals of its body mass (regression equation and graph for mammals in general) and is the first such count for a cetacean. The total glomerular mass relative to parenchymal renal mass of the O. orca infant and adult is, nevertheless, 5.5% and 6.0%, respectively, and is thus close to the general mammalian value of approximately 5%.

CONCLUSIONS

Organization of a cetacean kidney into numerous renicules does not increase specific renal parenchymal mass or specific glomerular mass. The apparent advantage of numerous independent renicules is the limit that is afforded for length of tubules in the necessarily large kidneys of gigantic mammals.

Spiral computed tomography for staghorn calculi

OBJECTIVES

To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction for preoperative planning of percutaneous nephrostolithotomy in patients with complex branched calculi (full staghorns).

METHODS

Patients with complex branched stones were imaged with spiral CT with three-dimensional reconstruction. These images were compared with standard imaging modalities, including excretory urography and plain radiographs, for planning percutaneous access for nephrostolithotomy. The utility of the scan was evaluated.

RESULTS

Ten patients with branched calculi were studied. Anatomic abnormalities were present in 5 patients. Excellent three-dimensional images were obtained in all patients without any complications related to the study. In 1 patient with multiple calculi in a horseshoe kidney, the three-dimensional image indicated a branched stone. The spiral CT scan was not helpful in directing percutaneous access in any patient. In a single patient, residual fragments noted during nephrostolithotomy were located by reference to the spiral CT scan.

CONCLUSIONS

Spiral CT scans with three-dimensional reconstruction provide three-dimensional imaging of branched renal calculi. This modality provides minimal additional information over that obtained from standard radiographic studies for guiding nephrostolithotomy and cannot be recommended as a routine preoperative study. It was helpful in 1 patient to locate a residual fragment.

Management of calyceal calculi

Management of calyceal calculi has changed dramatically during the past 20 years. Minimally invasive techniques virtually have replaced open surgical stone removal. Even large and complex calyceal calculi may be treated effectively with these minimally invasive techniques. Although open surgical stone removal is performed infrequently, a clear understanding of the subtle renal anatomy aids the urologist in more effectively treating patients with calyceal calculi and in limiting surgical complications.

3-dimensional imaging of the pelviocaliceal system by computerized tomographic reconstruction

Safe and efficient performance of percutaneous nephrolithotomy requires 3-dimensional visualization of the pelviocaliceal anatomy. However, currently available modalities offer only 2-dimensional images, from which the operator must mentally reconstruct a 3-dimensional picture of the pelviocaliceal configuration. We evaluated the feasibility of obtaining 3-dimensional images of the pelviocaliceal system with the aid of computerized tomographic reconstruction and present 3 illustrative cases.

Radiological anatomy of the kidney revisited

In recent years some structures or features such as the "inter-renuncular septum", the "echogenic triangle" and the "echogenic line" have been described to support the concept of a kidney resulting from the fusion of two masses or renunculi. To clarify this concept and to understand the meaning of the above echographic features better, the authors have examined prospectively by sonography the kidneys of 50 children, 200 adults with a single collecting system, 25 adults with a duplicated collecting system and 32 cadavers. Furthermore, to help explain the sonographic features, we have examined 32 cadaver kidneys with sonography and 10 cadaver kidneys with magnetic resonance imaging (MRI). The sonographic, MRI and anatomical correlations have shown that the "echogenic triangle" and the "echogenic line" are not renuncular residuals, but simply an extension of the hilar fat visible when the renal sinus is rather deep. The intermediate cortical mass is not a septum dividing the kidney into an upper and lower renunculus, but a column of parenchymal tissue crossing the renal sinus, which, from an anatomical point of view, is an accessory renal lobe. The presence of two renunculi, suggested in a previous study with cortical nephrotomography, has not been confirmed.

Anatomical relationship between the intrarenal arteries and the kidney collecting system

The anatomical relationship between the intrarenal arteries and the renal collecting system was studied in 82, 3-dimensional endocasts. Some anatomical details that have importance for urologists were observed. The arterial supply related to the upper caliceal group arises from 2 arteries that encircle these calices (in 86.6% 1 trunk originated from the anterior division and 1 from the posterior division of the renal artery). The artery to the mid kidney courses horizontally in the mid renal pelvis in 64.6% of the cases while the arterial supply to the inferior pole (front and back) arises from the inferior segmental artery of the anterior division in 62.2%. The posterior segmental artery is related to the upper infundibulum or to the junction of the pelvis with the upper calix in 57.3% of the cases and to the middle posterior aspect of the renal pelvis in 42.7%.

Renal anatomy of the manatee, Trichechus manatus, Linnaeus

The manatee kidney is composed of several closely apposed lobes. These are formed by cortical folds (plicae corticales) that completely isolate the medullae, except where the medullae of adjacent lobes are partially fused. The cortex is continuous; its folds usually are separated, but only partially, by interlobar septa extending from the renal capsule. The cortex makes up approximately 57% of renal mass in adults and 68% in the calf. There are about 3 million glomeruli per kidney. The average is somewhat less than that expected of an adult eutherian of equal mass. The glomeruli, however, are large; they form 7.38% +/- 1.33 of cortical mass, which is above that for at least ten unrelated adult eutherians. The number of glomeruli per gram of cortex is considerably greater in the calf than in the adult. The medullae are about 43% of renal mass. The cortico-medullary thickness ratio is 0.08 to 0.24. All terminal collecting ducts open at a crater (cratera cribrosa) of varying depth. Hair-pin loops occur at all levels of medulla, and apparently all loops bend at their thick segment. Cortical loops occur in the medullary rays. Vascular bundles were evident at the cortico-medullary border and thin tubules extended into the medulla from the central ends of the medullary rays (cortical) in seven out of the nine kidneys. The renal pelvis is separated from the central ends of the cortical folds by delicate fascia through which pass the interlobar vessels. There are no fornices and no infundibula. The collagenous tissue of the pelvic wall extends across most of the pelvic surface of the outer medulla.

3-Dimensional and radiological pelviocaliceal anatomy for endourology

The renal collecting system was studied in 100, 3-dimensional corrosion casts and also in 40 casts with the corresponding pyelograms. Some anatomical details that have great importance for endourology were observed and discussed, including the presence of perpendicular minor calices draining into the surface of the collecting system (11 per cent of the cases), crossed calices in the mid kidney with consequent formation of a region that we termed the inter-pelviocaliceal region (17.1 per cent), position of the calices related to the lateral kidney margin (in 52.9 per cent the anterior and posterior calices were superimposed or alternately distributed), position of the calices related to the polar regions (superior pole with a midline caliceal infundibulum in 98.6 per cent and inferior pole with paired calices in 57.9 per cent) and to the mid kidney (with paired calices in 95.7 per cent), and bilateral symmetry of the casts (37.1 per cent). The urologist must appreciate these anatomical structures during operations on the collecting system.

Detailed caliceal anatomy for endourology

A thorough understanding of caliceal anatomy is required to interpret excretory urograms and to perform safely endourological manipulations. Caliceal angles, posterior rotation of the lateral renal margin and caliceal placement in relation to the lateral aspect of the body were studied in 26 right and 24 left kidneys. Differences between kidneys found to be Brödel's types from those of the Hodson type, and the significance of these findings for performing nephrostolithotomy are described.

Sonographic evaluation of hypertrophy of septum of Bertin

Sonography was utilized to evaluate 12 patients with hypertrophy of the septum of Bertin. To confirm the diagnosis, angiography was used in 7 patients and radionuclide imaging in 2. Three sonographic characteristics were found: (1) an isoechogenic, ellipsoid mass with an echogenic linear rim of renal sinus fat; (2) contiguity of the mass with a normal-placed septum of Bertin; and (3) the occurrence of the mass effect always at the level of the emergence of the renal vein. The sonographic findings could be divided into two definite types. Type I showed moderate hypertrophy with a mass effect ranging from 1.1 by 2.3 cm to 2.0 by 3.2 cm in diameter, usually presenting with a smooth contour and discrete mass effect on the intravenous pyelogram (IVP). Type II showed severe hypertrophy with a mass effect ranging from 3.2 by 4.0 cm to 3.5 by 4.5 cm in diameter, usually presenting with a lobulated contour and irregular stretching of the calyceal system on IVP. The differential diagnosis is discussed. In conclusion, we found that sonography associated with excretory urography is an accurate method for the diagnosis of hypertrophy of the septum of Bertin.

Advances in radiological anatomy of the kidney

While using cortical nephrotomography to show the architecture and thickness of the cortical septa we have observed, in 76 out of 176 kidneys, the presence of 2 distinct parenchymal elements for which we suggest the term "renunculus". In such cases the upper renunculus is posterior relative to the lower. It lies rather obliquely, running downwards and laterally, while the lower renunculus lies more or less vertically and in front of the upper. The hilum of the upper renunculus as seen on CT is directed anteriorly relative to the corneal plane: the hilum of the lower renunculus is directly more medially. These anatomical observations make it easier to understand the topography and the pathogenesis of some lesions and help the surgeon to plan partial nephrectomy.

Management of the papillae during intrarenal surgery

The intersegmental nature of renal incisions is axiomatic. Deviation from the intersegmental plane is hazardous. If divided along intra-arterial planes papillae appear to heal with little structural or functional impairment.

Some observations on the medulla of the kidney

Terminology of the cortex of the kidney is discussed and some new terms are suggested. Observations are described on 50 kidneys which have been injected and variously dissected. These include descriptions of the medulla, papillae and calyces. Some developmental, radiological and surgical aspects are mentioned and suggestions for further study are made.

Magnification renal scintigraphy in the differential diagnosis of septa of Bertin

Eight consecutive patients, referred because intravenous urography (IVP) raised the question of hypertrophied septum of Bertin versus a pathologic mass, were examined using 99mTc labeled radiopharmaceuticals with magnification renal scintigraphy. The areas of concern showed a spectrum of activity, from normal to markedly increased, as compared to surrounding tissue. The activity correlated with the size of the mass effect on IVP. Increased resolution provided by pinhole magnification was important in evaluating these patients. We feel that magnification renal scintigraphy is valuable in the evaluation of intrarenal masses.

An anomalous calyx in the mid-kidney: an anatomical variant

Three cases in which there was an anomalous short calyx without a papilla in the mid kidney are described. This is believed to be a developmental abnormality which is associated with a pelvicalyceal pattern of two major calyces, and with renal "pseudotumour". It is important to recognize this calyceal appearance in order to distinguish it from calyceal disease.