Imaging of Small Renal Masses before and after Thermal Ablation.

Thermal ablation of small renal masses is increasingly accepted as an alternative to partial nephrectomy, particularly in patients with multiple comorbidities. Many professional societies support this alternate treatment with updated guidelines. Before performing thermal ablation, it is important to stratify risk and assess technical feasibility by evaluating tumor imaging features such as size, location, and centrality. Routine postablation imaging with CT or MRI is necessary for assessment of residual or recurrent tumor, evidence of complications, or new renal masses outside the ablation zone. The normal spectrum and evolution of findings at CT and MRI include a halo appearance of the ablation zone, ablation zone contraction, and ablation zone calcifications. Tumor recurrence frequently manifests at CT or MRI as new nodular enhancement at the periphery of an expanding ablation zone, although it is normal for the ablation zone to enlarge within the first few months. Recognizing early tumor recurrence is important, as small renal masses are often easily treated with repeat ablations. Potential complications of thermal ablation include vascular injury, urine leak, ureteral stricture, nerve injury, and bowel perforation. The risk of these complications may be related to tumor size and location.©RSNA, 2019.

[A Case Report : Metastatic Carcinoma of the Collecting Ducts of Bellini in a Hemodialysis Patient Treated with Temsirolimus].

Carcinoma of the collecting ductsof Bellini isa rare histological subtype of renal cell carcinoma and mostly has unfavorable prognosis. Radical nephrectomy is generally chosen for the 1st line treatment but therapeutic approaches for the metastasis/recurrence have not been established. We report a case of carcinoma of collecting ducts of Bellini in a patient receiving hemodialysis treated with temsirolimus. A 62- year-old man receiving hemodialysis was admitted to our hospital with drug-resistant anemia and high-grade cyclic fever. Computed tomography revealed the right renal tumor and multiple metastatic lung tumors. Open radical nephrectomy wasperformed. Pathological findingswere compatible with carcinoma of the collecting ducts of Bellini. He was given weekly temsirolimus treatment. The disease progressed modestly but kept the stable disease (SD) status for six months. He died of the cancer 11 months after the initial diagnosis.

Right lump kidney with varied vasculature and urinary system revealed by multidetector computed tomographic (MDCT) angiography.

Renal ectopia also known as ectopic kidney is an embryological renal anomaly characterised by abnormal anatomical location of one or both of the kidneys. This can occur in various forms such as (1) crossed fused renal ectopia, (2) ectopic thoracic kidney and (3) pelvic kidneys. The lump kidney is one of the six variations of crossed fused ectopic kidney. Throughout life, the patient may remain asymptomatic, however, symptomatic patients may present with minor traumatic injuries due to the abnormal location or normal kidney pathologies. During normal embryological development, there is cephalic migration during which the kidneys ascend to their normal retroperitoneal location; therefore, an ectopic location is as a result of arrested migration. During this embryological development the kidney has multiple aorto-illiac branches, which degenerate when the kidney reaches its normal location. Here they develop new renal branches from the aorta and during an arrested ascent the ectopic kidney tends to retain some of the older aorto-iliac vessels. Hence, the arterial supply and the veineux drainage are grossly abnormal, reflecting the metanephric malascent and the primitive vascular arrangement. The collecting systems also present with important anatomical variations. We present an extremely rare case of right lump kidney with six renal arteries, two renal veins and two duplicated pelvicalyceal systems.

CT urography for the diagnosis of medullary sponge kidney.

BACKGROUND: Medullary sponge kidney (MSK) is characterized by malformation of the terminal collecting ducts and is associated with an increased risk of nephrolithiasis, nephrocalcinosis, urinary tract infections, renal acidification defects, and reduced bone density. It has been historically diagnosed with intravenous pyelography (IVP), which is falling out of favor as an imaging modality. CT urography (CTU) performed with multidetector CT (MDCT) has been shown to create images of the renal collecting system with similar detail as IVP; however, its utility in diagnosing MSK has not been defined. CASE REPORT: We present the first 15 patients with recurrent symptomatic nephrolithiasis who were evaluated in our renal stone clinic with CTU. Four patients were diagnosed with MSK after visualization of the characteristic radiologic findings. DISCUSSION: CTU effectively demonstrates the characteristic radiologic findings of MSK including collecting tubule dilatation, medullary nephrocalcinosis, nephrolithiasis, and medullary cysts. Dose reduction protocols can reduce radiation exposure below that associated with conventional IVP. We propose CTU be considered for the diagnosis of MSK.

Captopril renography as a prognostic factor in obstructive hydronephrosis with preserved renal function.

Hydronephrotic kidney with a differential renal function greater than 55% is defined as supranormal. The signification of this finding remains controversial. In this article, the authors reported a case of supranormal function in obstructive hydronephrosis. Differential renal functions were evaluated after administration of captopril and after pyeloplasty. The role of captopril renography as a prognostic factor for surgery is discussed.

Bilateral renal haematuria and obstructive renal failure from acquired haemophilia A: a medical cause for a surgical problem.

A 55-year-old male presented to our emergency department with haematuria and abdominal pain. Investigations including a computed tomography (CT) scan revealed an intraluminal filling defect within the left collecting system, consistent in appearance with blood clot. With an initial working diagnosis of upper tract urothelial cell carcinoma, he was discharged with plans for an urgent cystoscopy and ureteroscopy. He subsequently represented with ongoing frank haematuria, anasarca, dropping haemoglobin and new right collecting system blood clot. Subsequent investigations showed that the patient had acquired haemophilia A resulting in the episodes of haematuria, highlighted after an elevated activated partial thromboplastic time prompted a thrombophilia screen. The patient was subsequently treated with factor eight inhibitor bypass activity, corticosteroids and cyclophosphamide.

Collecting system involvement by renal tumor: are CT measurements reliable enough?

OBJECTIVES: Smaller kidney lesions which are more often detected recently by accidental imaging are amenable for nephron sparing approach whether at open surgery, laparoscopy or ablative techniques. The pretreatment planning is based on multiplanner CT expected to well define the relationship of the lesion to the major renal blood vessels and collecting system (CS). This study is aimed to compare the pre-surgical CT measurements of the distance from tumor to CS to the actual distances observed on radical nephrectomy specimens. PATIENTS AND METHODS: Contrast CT of 39 patients with renal cell carcinoma (RCC) underwent measurements of the distance between CS and renal tumor. All measurements were confronted with the measurements performed on radical nephrectomy specimens of the same patients. RESULTS: Of all 39 patients in 34 (87%) CT showed a contact relation between the tumor and the CS. In fact, the CS involvement has been histologically proven only in three (7.6%) cases. Cutting off the measurements at thresholds of 2 and 5 mm also showed a significant discrepancy between CT and specimen measurements. CONCLUSIONS: The trend of NSS and ablative techniques stressed out the importance of pretreatment measurements of the distance between the tumor and the CS. This study as performed on radical nephrectomy specimens points out the overestimated proximity of the tumor to the CS. These data if confirmed by other studies, may play a role while planning the management of NS approaches.

Renal Contrast on CT Myelography: Diagnostic Value in Patients with Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: The significance of renal contrast on CT myelography is uncertain. This project examined different patient populations undergoing CT myelography for the presence of renal contrast to determine whether this finding is of diagnostic value in spontaneous intracranial hypotension. MATERIALS AND METHODS: Four groups of patients were analyzed for renal contrast on CT myelography. The control group underwent CT myelography for reasons other than spontaneous intracranial hypotension (n = 47). Patients in study group 1 had spontaneous intracranial hypotension but CT myelography negative for dural CSF leak and CSF venous fistula (n = 83). Patients in study group 2 had spontaneous intracranial hypotension and CT myelography positive for dural CSF leak (n = 44). Patients in study group 3 had spontaneous intracranial hypotension and CT myelography suggestive of CSF venous fistula due to a hyperdense paraspinal vein (n = 17, eleven surgically confirmed). RESULTS: Renal contrast was present on the initial CT myelography in 0/47 patients in the control group, 10/83 patients in group one, 1/44 patients in group 2, and 7/17 patients in group 3. Renal contrast on initial CT myelography in patients with suspected or surgically confirmed CSF venous fistula was significantly more likely than in patients with a dural CSF leak (P = .0003). CONCLUSIONS: Renal contrast on initial CT myelography was seen only in patients with spontaneous intracranial hypotension. This was more common in confirmed/suspected CSF venous fistulas compared with dural leaks. Early renal contrast in patients with spontaneous intracranial hypotension should prompt scrutiny for a hyperdense paraspinal vein, and, if none is found, potentially advanced diagnostic studies.

Bilateral duplex collecting system with bilateral vesicoureteral reflux: a case report.

BACKGROUND: A bilateral duplex collecting system is an unusual renal tract abnormality. Vesicoureteral reflux may be associated. We describe a rare case of bilateral duplex collecting system with bilateral vesicoureteral reflux in which the refluxing ureter on the left side drains the upper pole moiety contrary to what is often found. CASE PRESENTATION: A 24-year-old married Arab woman presented with ascending left-sided flank pain during micturition. She complained of recurrent urinary tract infections. A physical examination and laboratory tests were normal. Voiding cystourethrography and computed tomography scan detected bilateral duplex collecting system, grade IV vesicoureteral reflux on the left side, and grade I vesicoureteral reflux on the right. She underwent left heminephrectomy and dextranomer/hyaluronic acid injections on the right side. After a year of follow-up, a clinical examination and imaging findings were unremarkable. CONCLUSIONS: A bilateral duplex collecting system with refluxing upper pole moiety ureter is a very rare entity. The diagnosis should be suspected when exploring any flank pain with recurrent urinary tract infections to avoid subsequent renal impairment. Furthermore, this case shows how some common symptoms may lead to finding an unexpected urinary tract abnormality.

Renal ablation by histotripsy--does it spare the collecting system?

PURPOSE: The feasibility of histotripsy (transcutaneous nonthermal mechanical tissue fractionation) was previously demonstrated in an in vivo rabbit renal cortex model. We explored the spectrum of histotripsy bio-effects on different tissue types in an in vitro porcine kidney model. MATERIALS AND METHODS: Using an 18 element focused annular array ultrasound system we performed histotripsy treatments in 5 in vitro porcine kidneys, targeting 7 cortical volumes and 17 tissue volumes bridging the cortex, medulla and/or collecting system. Treated areas were observed using ultrasound. In 5 lesions methylene blue was infused into the collecting system to evaluate the preservation of collecting system integrity. Kidneys were sectioned and examined grossly for evidence of tissue fractionation, ie the presence of histotripsy paste, or fixed in formalin and prepared for histological analysis. RESULTS: Histotripsy of renal cortical tissue created tissue defects in the cortical area treated. Histotripsy targeting the renal collecting system, medulla and renal cortex resulted in tissue fractionation in the area of the cortex, intermediate damage in the medulla and minimal damage to the collecting system. CONCLUSIONS: There is a differential histotripsy treatment effect when comparing renal cortical tissue to renal collecting system. There is no significant architectural disruption of the renal collecting system after histotripsy. This differential effect is a notable finding that may prove useful in future planning of ablative treatments for renal tissue.

High frequency and wide range of human kidney papillary crystalline plugs.

Most of kidney stones are supposed to originate from Randall's plaque at the tip of the papilla or from papillary tubular plugs. Nevertheless, the frequency and the composition of crystalline plugs remain only partly described. The objective was to assess the frequency, the composition and the topography of papillary plugs in human kidneys. A total of 76 papillae from 25 kidneys removed for cancer and without stones were analysed by immunohistochemistry combined with Yasue staining, field emission-scanning electron microscopy and Fourier transformed infrared micro-spectroscopy. Papillary tubular plugs have been observed by Yasue staining in 23/25 patients (92%) and 52/76 papillae (68%). Most of these plugs were made of calcium phosphate, mainly carbonated apatite and amorphous calcium phosphate, and rarely octacalcium phosphate pentahydrate. Calcium and magnesium phosphate (whitlockite) have also been observed. Based upon immunostaining coupled to Yasue coloration, most of calcium phosphate plugs were located in the deepest part of the loop of Henle. Calcium oxalate monohydrate and dihydrate tubular plugs were less frequent and stood in collecting ducts. At last, we observed calcium phosphate plugs deforming and sometimes breaking adjacent collecting ducts. Papillary tubular plugging, which may be considered as a potential first step toward kidney stone formation, is a very frequent setting, even in kidneys of non-stone formers. The variety in their composition and the distal precipitation of calcium oxalate suggest that plugs may occur in various conditions of urine supersaturation. Plugs were sometimes associated with collecting duct deformation.

Soft 3D-Printed Phantom of the Human Kidney with Collecting System.

Organ models are used for planning and simulation of operations, developing new surgical instruments, and training purposes. There is a substantial demand for in vitro organ phantoms, especially in urological surgery. Animal models and existing simulator systems poorly mimic the detailed morphology and the physical properties of human organs. In this paper, we report a novel fabrication process to make a human kidney phantom with realistic anatomical structures and physical properties. The detailed anatomical structure was directly acquired from high resolution CT data sets of human cadaveric kidneys. The soft phantoms were constructed using a novel technique that combines 3D wax printing and polymer molding. Anatomical details and material properties of the phantoms were validated in detail by CT scan, ultrasound, and endoscopy. CT reconstruction, ultrasound examination, and endoscopy showed that the designed phantom mimics a real kidney's detailed anatomy and correctly corresponds to the targeted human cadaver's upper urinary tract. Soft materials with a tensile modulus of 0.8-1.5 MPa as well as biocompatible hydrogels were used to mimic human kidney tissues. We developed a method of constructing 3D organ models from medical imaging data using a 3D wax printing and molding process. This method is cost-effective means for obtaining a reproducible and robust model suitable for surgical simulation and training purposes.

CT and MR imaging of complications of partial nephrectomy.

The standard treatment for renal cell carcinoma for many years was radical nephrectomy, but in the past decade there has been a trend toward elective nephron-sparing surgery. Initially, partial nephrectomy was performed with an open surgical approach; more recently and with increasing frequency, a laparoscopic approach has been used in selected cases. Nephron-sparing surgery with either approach is more complex than is traditional radical nephrectomy and more frequently results in complications. The possible complications of partial nephrectomy include vascular, collecting system, and technical complications as well as recurrent tumor and infection. For prompt diagnosis and appropriate management of these complications, radiologists must be familiar with normal and abnormal features in the postoperative appearance of the kidney at computed tomography and magnetic resonance imaging.

Robot assisted heminephrectomy for duplicated renal collecting system: technique and outcomes.

BACKGROUND: The aim of this study was to describe experience with robotic assisted hemi-nephrectomy (RAHN) for the management of duplicated renal collecting system. METHODS: The authors' institutional database was queried to identify patients who underwent RAHN from 2007 to 2013 for the management of a duplicated system. Patient demographics, indications and surgical outcomes were reviewed and analyzed. RESULTS: Five patients were identified with a duplicated system of which all had a history of pain and recurrent infection. Three patients underwent hemi-nephrectomy for a poorly functioning lower pole and two for an abnormal upper pole moiety. All operations were completed successfully using a robotic approach. There were only two minor (Clavien grade 1-2) complications. CONCLUSIONS: RAHN is a viable option for the surgical treatment of an atrophic, chronically infected duplicated system. The unique features of robotic technology offer enhanced dexterity and vision facilitating the management of complex vascular and ureteral anatomy.

Effect of hydration and dehydration on technetium-99m CO2 DADS renal studies in normal volunteers.

Ten normal volunteers were studied in the hydrated and dehydrated states with the new renal radiopharmaceutical technetium-99m N,N'-bis(mercapto acetyl)-2, 3-diaminopropanoate [( 99mTc]CO2 DADS). The data were used to determine the effect of hydration and dehydration and to determine the normal range in each state. Visual evaluation of the images indicated that the first appearance of tracer in the collecting system was approximately the same in either state, that the concentration of tracer in the collecting system was always higher in the dehydrated state (p less than 0.01), and that the ureters always appeared more segmented in the dehydrated state (p less than 0.01). Quantitative analysis of the images indicated that the kidney to background ratio 1-2 min after injection was somewhat greater in the dehydrated state (13.5 +/- 4.0) than in the hydrated state (9.8 +/- 2.2) (p less than 0.05), that the size of the bladder was always greater in the hydrated state (p less than 0.05), and there was no difference in the amount of tracer in the bladder at 30 min after injection. The results define the normal hydrated and dehydrated [99mTc]CO2 DADS renal study and identify several differences between the two states which can be explained primarily by differences in urine flow rates.

Microradiography of the collecting ducts in the perfusion fixed rabbit kidney: suggestions for the anatomic basis for the radiographic appearance of cortical striations and intrarenal reflux.

Perfusion fixation was used to preserve the rabbit kidney, in its in vivo state (open tubules). Barium sulfate was either injected through the renal artery at a pressure sufficient to cause postulated microruptures in the glomerular tufts and opacify the tubules, or refluxed via the ureter to opacify the collecting ducts and tubules to the level of Bowman's capsule. The anatomy of the collecting ducts and their relationships to the nephrons were demonstrated, allowing suggestions for the anatomical basis for the radiographic appearances of cortical striations and intrarenal reflux.

Dilated renal collecting systems: differentiating obstructive from nonobstructive dilation using duplex Doppler ultrasound.

Two patients with ileal loop urinary diversions, studied with real-time and Doppler sonography ("duplex sonography") of the kidneys, were shown to have dilated intrarenal collecting systems. Resistive index measurements calculated from the Doppler signal correctly identified obstructive dilatation in 1 case and nonobstructive dilatation in the other.