Computed Tomography Urography for Diagnosis of Calyceal Diverticulum Complicated by Urolithiasis: The Accuracy and the Effect of Abdominal Compression and Prolongation of Acquisition Delay

Calyceal Diverticulum Found Incidentally on 18 F-FDG PET/CT Imaging

ABSTRACT

A 69-year-old man with pancreatic cancer underwent 18 F-FDG PET/CT examination for tumor staging. The PET images showed a focal mass-like FDG accumulation in the left kidney mimicking malignancy, whereas simultaneous CT and fused PET/CT images suggested a cystic lesion. On subsequent MR examination, the lesion appeared cystic on T2-weighted, contrast-enhanced arterial phase, and contrast-enhanced venous phase images. In addition, excretory phase images showed filling contrast medium to the cystic cavity, leading to a diagnosis of calyceal diverticulum. This report suggests that the possibility of a calyceal diverticulum should be considered in cases with focal FDG accumulation in renal cystic lesions.

Prolonged postoperative urine leakage due to a calyceal diverticulum mimicking a renal cyst: A case report and literature review

Background

The calyceal diverticulum is a rare cystic cavity that communicates with the collecting system via a narrow neck or infundibulum. In clinical practice, part of the calyceal diverticula is difficult to differentiate from simple renal cysts even after contrast-enhanced CT. To date, there have been few kinds of literature works on the diagnosis and treatment of calyceal diverticulum combined with renal pelvis dilatation, especially concerning the treatment of prolonged postoperative urine leakage.

Case description

A 53-year-old woman with calyceal diverticulum and renal pelvis dilatation mimicking a simple renal cyst suffered urine leakage after receiving laparoscopic unroofing of the renal cyst. A persistent urine leakage was observed immediately after surgery, with about 200 ml of drainage fluid per day. We first attempted to place a double-J ureteral stent and indwell a catheter. After failing that, conservative treatment was performed. The core idea of the conservative treatment is retaining the drainage tube for more than 1 month, then clamping the drainage tube for 1 week, and finally removing the drainage tube. By 3 weeks of follow-up, the urine leakage disappeared, and the CT scan showed hydronephrosis of the right kidney without perirenal exudation and the lower pole cyst of the right kidney shrank significantly.

Conclusion

This case, we reported here, is to attract the attention of clinicians. Renal cysts should exclude the possibility of the calyceal diverticulum. If urine leakage is inevitable after surgical treatment, our conservative treatment strategy is also an alternative method.

Differentiation of simple renal parenchymal cyst and calyceal diverticulum

BACKGROUND

Calyceal diverticulum is the cystic eventration of the upper urinary tract within the renal parenchyma, which gives the first impression of a simple renal cyst and therefore can easily be misdiagnosed. We conducted a study to assess the role of static-fluid magnetic resonance (MR) urography in the differentiation of renal parenchymal cysts and calyceal diverticulum in comparison with focused renal ultrasonography (US).

METHODS

Focused renal US, static-fluid, and excretory MR urography studies of 45 children who were admitted to our pediatric nephrology department with a diagnosis of renal cyst were reviewed retrospectively. Excretory MR urography was accepted as gold standard for the diagnosis of calyceal diverticulum. Sensitivity and specificity of focused renal US and static fluid MR urography in the diagnosis of renal calyceal diverticulum were assessed. Interobserver agreement between three radiologists in the diagnosis of calyceal diverticulum on MRI was also evaluated.

RESULTS

The study included 29 patients (13 boys and 16 girls) aged between 6-18 years (mean 11.5 ± 4.1). Five calyceal diverticula and 24 solitary renal parenchymal cysts were diagnosed. The sensitivity and the specificity of focused renal US were 40% and 100% in the diagnosis of calyceal diverticulum. The sensitivity and the specificity of static-fluid MR urography were 100% and 91.6%, respectively. The degree of interobserver agreement was excellent for the diagnosis of diverticulum for static-fluid MR urography (κ = 0.86, 95% CI: 0.71-1.00).

CONCLUSIONS

Static-fluid MR urography can be successfully used in children for the differentiation of renal parenchymal cyst and calyceal diverticulum due to its high sensitivity and specificity, without exposing children to ionizing radiation or intravenous contrast agents.

Challenges in the diagnosis of calyceal diverticulum: A report of two cases and review of the literature

BACKGROUND

Calyceal diverticula outpouchings that occur rarely in the upper collecting system of the kidney and is often difficult to detect. In this study, we present two cases of calyceal diverticula and discuss their clinical characteristics and radiologic features.

PATIENTS AND METHODS

In the presented two cases, we applied several imaging examinations, including delayed intravenous pyelography, retrograde pyelography and axial computerized tomographic (CT) scanning of the kidneys with and without contrast. Serum creatinine levels in fluid withdrawn from the diverticula were found to be significantly higher than the simultaneous serum creatinine levels. Intravenous injection of methylene blue through a ureteral catheter was also aided in the diagnosis. Calyceal diverticulum neck dilatation was performed through a percutaneous nephroscope.ResultsThe two cases were diagnosed preoperatively and the operation was successful performed. The nephrostomy tube was removed seven days after surgery without complications. CT scans of the kidney after six months showed that the size of the calyceal diverticulum of two patients were considerably smaller than pre-surgery. There were no reports of pain in the lumbar region or other discomfort.

COMMENTS

Diagnosis of calyceal diverticulum mainly depend on a variety of imaging examinations, including the delayed intravenous pyelography, retrograde pyelography, and kidney CT plain scan plus enhanced scan. If the patient cannot be diagnosed by above methods, cyst fluid can be aspirated percutaneously to measure the preoperative creatinine level. If it is significantly higher than the serum creatinine level, the cyst fluid is considered urine, which can assist in the diagnosis of calyceal diverticulum. A ureteral catheter should also be inserted before operation namely, intravenous injection of methylene blue through a ureteral catheter is helpful for diagnosis. The choice of surgical treatment is based on the size and location of calyceal diverticulum and clinical manifestations.

A Petal-like Calyceal Diverticulum

Calyceal diverticula are rare outpouchings of the upper collecting system that likely have a congenital origin. They are usually single cystic lesions accompanied by stones inside them and located in the upper pole calyces. We present a case containing a petal-like cystic lesion with multiple septa in the lower pole of the left kidney, which was confirmed as calyceal diverticulum by computed tomography urography and intraoperative findings.

Potential Role of Tc-99m DTPA Diuretic Renal Scan in the Diagnosis of Calyceal Diverticulum in Children

The aim of the study was to assess the usefulness of Technetium-99m diethylene triamine pentaacetic acid (Tc-99m DTPA) diuretic scan to diagnose calyceal diverticulum (CD). From January 2000 to June 2014, children with evidence of renal cystic lesions of undetermined diagnosis on ultrasound were enrolled. Computed tomography urography (CTU) and Tc-99m DTPA diuretic scan were performed to characterize the precise anatomy. The diagnosis of CD depended on visualization of a renal cystic lesion with filling of contrast material or radiotracer from the collecting system on CTU or diuretic renal scan. Children who had positive findings of CD on 1 or both imaging studies were selected and analyzed. Both CTU and Tc-99m DTPA diuretic renal scan were performed in 39 children. A total of 9 (23.1 %) children with CD were diagnosed. All 9 children had positive diagnosis of CD on diuretic renal scan. Only 6 (66.7%) children could be diagnosed by CTU, and CD was missed by CTU in 3 subjects. The differential renal functions in patients with CD were 46% to 55%. The time of radiotracer appearance in the CD ranged from the 8th to the 24th minute. Seven patients had persistent accumulation of radiotracer in their CD at the end of the study. Tc-99m DTPA diuretic renal scan seems to be more sensitive than CTU in diagnosing CD. The possible reasons of higher sensitivity are discussed. Additional advantages that Tc-99m DTPA diuretic renal scan provides include the following: continuous monitoring, less radiation doses, and information on renal function, making it an attractive alternative to CTU for diagnosis of CD.

Calyceal diverticulum mimicking simple parapelvic cyst: a case report

Calyceal diverticulum is a cystic intrarenal cavity lined by nonsecretory transitional epithelium that communicates with the collecting system via a narrow isthmus or infundibulum. It is a rare anatomic anomaly with an incidence of 0.2% to 0.6% in the patients undergoing renal imaging.1 Single imaging modality usually cannot differentiate calyceal diverticulum from other cystic renal diseases.2 Here, we report a 60-year-old male who was reliably diagnosed with calyceal diverticulum by retrograde urography combined with non-enhanced computed tomography (CT) and magnetic resonance urography (MRU).