Imaging of Bladder Cancer: Standard Applications and Future Trends

The evolution in imaging has had an increasing role in the diagnosis, staging and follow up of bladder cancer. Conventional cystoscopy is crucial in the diagnosis of bladder cancer. However, a cystoscopic procedure cannot always depict carcinoma in situ (CIS) or differentiate benign from malignant tumors prior to biopsy. This review will discuss the standard application, novel imaging modalities and their additive role in patients with bladder cancer. Staging can be performed with CT, but distinguishing between T1 and T2 BCa (bladder cancer) cannot be assessed. MRI can distinguish muscle-invasive from non-muscle-invasive tumors with accurate local staging. Vesical Imaging-Reporting and Data System (VI-RADS) score is a new diagnostic modality used for the prediction of tumor aggressiveness and therapeutic response. Bone scintigraphy is recommended in patients with muscle-invasive BCa with suspected bony metastases. CT shows low sensitivity for nodal staging; however, PET (Positron Emission Tomography)/CT is superior and highly recommended for restaging and determining therapeutic effect. PET/MRI is a new imaging technique in bladder cancer imaging and its role is promising. Texture analysis has shown significant steps in discriminating low-grade from high-grade bladder cancer. Radiomics could be a reliable method for quantitative assessment of the muscle invasion of bladder cancer.

CT and MRI in Urinary Tract Infections: A Spectrum of Different Imaging Findings

There are many acute and chronic infections affecting the urinary tract including bacterial, fungal and viral infections. Urinary tract infections (UTIs) can present in many different patterns with variable degrees of severity varying from asymptomatic and uncomplicated forms to life threatening complicated infections. Cross-sectional imaging techniques—including both computed tomography (CT) and magnetic resonance imaging (MRI)—have become very important tools not only for evaluation of UTIs, but also for detection of associated complications. Selection of either CT or MRI in the UTI evaluation depends on several factors such as the presence of contraindication, experience, cost and availability. CT and MRI help in early detection and management of UTIs that reduce the prevalence and severity of complications. In this article we will present the radiologic findings at CT and MRI in different types of upper and lower UTIs including acute pyelonephritis, intrarenal and perinephric abscesses, pyonephrosis, chronic pyelonephritis, emphysematous UTIs, xanthogranulomatous pyelonephritis, tuberculosis (TB), bilharziasis, fungal infection, corynebacterium infection, ureteritis, cystitis, prostatitis, prostatic abscess and urethritis.

Ectopic insertion of the ureter into the seminal vesicle

We present a case of left ectopic ureter insertion into the left seminal vesicle which is a rare anomaly. The incidence of ectopic insertion of the ureter is more common in females and is usually associated with incontinence, leading to the diagnosis, while in males it is present with infection. Ectopic ureter is defined as abnormal insertion of the ureter, occurring in the posterior urethra in approximately 50% of cases in males. Other sites include the seminal vesicle (approximately one-third), vas deferens, bladder neck, prostate and epididymis, while the urethra and vagina are commonly affected in females. Management is usually addressed to the upper tract only; if there is incontinence it requires removal of the ureteric stump. Our case was initially diagnosed by magnetic resonance imaging and the diagnosis confirmed by computed tomography (CT) guided seminal vesiculography as transrectal guidance for seminal vesiculography was refused by the patient. CT guided seminal vesiculography is less painful and more tolerable than the transrectal route.

Low-dose unenhanced computed tomography for diagnosing stone disease in obese patients

Objective

To evaluate the detectability, size, location and density of urinary stones with unenhanced computed tomography (CT), using the half-radiation (low) dose (LDCT) technique, compared with the standard-dose CT (SDCT), in obese patients.

Patients and methods

The study included 50 patients with a body mass index of >30 kg/m² and bilateral renal stones diagnosed with SDCT, and managed on one side. All the patients had LDCT during the follow-up and SDCT was used as a reference for comparison.

Results

Of the 50 patients, the right side was affected in 27 and the left side in 23. In all, 35 patients had a single stone while the remaining 15 had multiple stones. With SDCT, 95 stones were detected; there were 45 of ⩽5 mm, 46 of 6–15 mm and only four of >15 mm. LDCT barely detected three stones of <3 mm, compared with SDCT, while larger stones had the same appearance at both scans. The site of stone in the kidney or the ureter did not affect its detection on LDCT vs. SDCT. The mean stone diameter was identical in both techniques. At LDCT, all stones were detected with no difference in their number, location or density vs. SDCT. However, the tube current and radiation dose were significantly lower with LDCT.

Conclusions

In obese patients with stone disease, LDCT is as accurate as SDCT, while avoiding exposure of the patient to high-dose radiation.

Radiological diagnosis of vesicouterine fistula: role of magnetic resonance imaging

PURPOSE

To retrospectively assess the value of magnetic resonance imaging (MRI) in the diagnosis of vesicouterine fistula (VUF).

MATERIALS AND METHODS

Between January 2003 and January 2011, 12 patients with a diagnosis of VUF were surgically managed at our center; among them, eight patients had MRI among their preoperative radiological investigations and those were included in our study. The clinical presentation, radiological investigations, and surgical findings of the patients were reviewed.

RESULTS

The mean age of the patients was 31 years. Seven of the eight patients had complaints of cyclic hematuria and the remaining patient complained of urinary leakage through the vagina. The etiology of VUF was cesarean section in all patients. The preoperative radiological investigations included conventional cystography in five patients, intravenous urography in two, computed tomography (CT) urography in two, and MRI in eight. The sensitivities of diagnosis for these investigations were 40%, 0%, 50%, and 100%, respectively.

CONCLUSION

In our small retrospective series, pelvic MRI was reliable and sensitive for diagnosis of VUF. It should be considered in the work-up of patients with suspected VUF.

Role of diffusion-weighted MRI in diagnosis of acute renal allograft dysfunction: a prospective preliminary study

OBJECTIVE

The aim was to evaluate the effects of diagnostic performance of diffusion-weighted (DW) MRI in the assessment of acute impairment of transplanted kidneys.

METHODS

From January 2009 to January 2010, 49 patients with stable renal allograft function (Group 1) and 21 patients with acute graft impairment (Group 2) were included in the study. All patients were evaluated with coronal T(2) weighted (T(2)W) and DW MRI of the kidney. Patients in Group 2 underwent graft biopsy to determine the underlying histopathological aetiology. Apparent diffusion coefficient (ADC) was calculated and the kidneys were studied for any areas of diffusion restriction. Two radiologists, who were blinded to the results of histopathology, independently interpreted the T(2)W and DW images.

RESULTS

The histopathological diagnosis of Group 2 (21 patients) was acute cellular rejection (ACR) in 10, acute tubular necrosis (ATN) in 7 and immunosuppressive toxicity in 4 patients. ADC values in Group 1 were significantly higher compared with Group 2 (p<0.001), patients with ACR (p<0.001), patients with ATN (p<0.001) and patients with drug toxicity (p<0.001). Using 2 × 10(-3) mm(2) s(-1) as a cut-off, there was no overlap between the ADC values of patients with normal graft function and those with ATN. Both ACR and ATN had a low ADC value, but on the ADC map the kidney in cases of ATN appears heterogeneous with a characteristic mosaic pattern resembling the Tiger skin. There was no significant T(2)W morphological difference between the two groups.

CONCLUSION

These results show how DW MRI is a promising new technique for the diagnosis of acute renal transplant dysfunction.

Adrenal Hemangioma: Findings at Multidetector CT with Short Review of the Literature

We present the computed tomography (CT) imaging findings of a 44-year-old male with incidentally discovered right adrenal hemangioma displaying imaging pattern of nonadenomatous pattern, associated with multiple hepatic hemangiomata using 64-slice multidetector scanner with reviewing published CT imaging findings with short review of the literature.

Characterization of solid renal masses using 64-slice multidetector CT scanner

The purpose of our study was to assess the role of a 64-slice multidetector CT (MDCT) scanner in the characterization of different solid renal masses, using a simplified approach to correct the postenhancement attenuation values. The study included 96 consecutive adults (58 men, 38 women) with renal masses; 93 with unilateral and three with bilateral masses. All of our patients underwent multiphasic CT study including pre- and postcontrast corticomedullary (CM) and nephrographic phases. We analyzed the images and corrected the postcontrast attenuation values at the CM phase. The postbiopsy or -surgical data were used as reference standard. There were 53 masses at the right kidney, 40 at the left kidney, and three bilateral. The final diagnosis of the 96 solid parenchymal masses were 28 clear-type renal cell carcinoma (RCC), 22 papillary-type RCC, 21 chromophobe-type RCC, six XP 11.2 chromosomal translocation–type RCC, 15 angiomyolipoma (AML), and seven oncocytoma. All the AML had fat, with attenuation values less than -40 HU at the nonenhanced scan. There is no difference in the precontrast attenuation values for the different types other than AML. At the postcontrast CM phase after the correction of the attenuation values, the clear cell type could be separated easily, with attenuation values >20 with specificity, sensitivity, and overall accuracy of 92, 84, and 93%, respectively. The 64-slice MDCT scanner with application of enhancement values correction allows diagnosis of clear cell carcinoma. Also, AML could be identified easily with fat inside at the precontrast scan.