Huda Refaie

Bladder tumour staging: comparison of diffusion- and T2-weighted MR imaging

The aim of this work was to evaluate the clinical feasibility of diffusion-weighted (DW) MRI in detection and staging of urinary bladder tumour and to compare DW MRI with the T2-weighted technique. One hundred and six patients with bladder tumour were prospectively included in our study. All patients were evaluated with MR imaging. We started with axial T2-weighted high resolution MR of the urinary bladder, then DW MRI. Two radiologists independently interpreted the MR images, and discrepancies were resolved by consensus. The accuracy of DW MRI in staging of bladder tumour was evaluated using the final histopathological findings. In DW imaging (DWI) staging accuracy was 63.6% and 69.6% in differentiating superficial from invasive tumours and organ-confined from non-organ-confined tumours, respectively. On a stage by a stage basis, DWI accuracy was 63.6% (21/33), 75.7% (25/33), 93.7% (30/32) and 87.5% (7/8) for stages T1, T2, T3 and T4, respectively. In the T2-weighted technique, the overall staging accuracy was only 39.6% and accuracy for differentiating superficial from invasive tumours and organ-confined from non-organ-confined tumours was 6.1% and 15.1%, respectively. DW is superior to T2-weighted MRI in staging of organ-confined tumours (≤T2) and both techniques are comparable in the evaluation of higher-stage tumours.

Bladder Cancer : Diagnosis with Diffusion-weighted MR Imaging in Patients with Gross Hematuria

PURPOSE To prospectively evaluate the usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging for the detection of bladder neoplasms in patients with gross hematuria of lower urinary tract origin. MATERIALS AND METHODS The study protocol received institutional ethical committee approval, and informed consent was obtained. Between April 2007 and March 2008, 130 consecutive patients with gross hematuria whose upper urinary tract had a normal appearance at ultrasonographic examination were prospectively enrolled. Mean age was 59.4 years (range, 45-75 years). All patients were evaluated by using T2-weighted high-spatial-resolution MR imaging of the urinary bladder, followed by DW MR imaging. Two radiologists independently interpreted the T2-weighted and DW images, and discrepancies were resolved by consensus. Agreement was evaluated by using the kappa statistic. All patients underwent conventional cystoscopy. With cystoscopy and the final histopathologic findings as the reference standards, a comparison with imaging findings was performed by using the McNemar test. RESULTS The consensus diagnostic performance of DW MR imaging for identification of bladder tumors was: sensitivity, 98.1% (104 of 106); specificity, 92.3% (24 of 26); PPV, 100% (104 of 104); negative predictive value, 92.3% (24 of 26); and accuracy, 97.0% (128 of 132). Two cases were falsely negative on T2-weighted MR images but were correctly diagnosed by using DW MR images. The agreement between DW MR imaging results and cystoscopic findings was excellent (kappa = 0.94) for identification of bladder neoplasm. DW MR imaging had a sensitivity and PPV of 98.5% (128 of 130) and 100% (128 of 128), respectively, for determining the cause of hematuria. CONCLUSION DW MR imaging is a highly reliable imaging approach for identification of bladder tumors in patients with gross hematuria.

Diffusion-Weighted MR Imaging in Diagnosis of Superficial and Invasive Urinary Bladder Carcinoma: A Preliminary Prospective Study

We conducted a prospective study to demonstrate the feasibility of using diffusionweighted (DW) magnetic resonance imaging (MRI) for the detection of urinary bladder carcinomas. Between January to June 2007, 43 patients with single bladder tumor were included in our study. Before taking a biopsy, DW MRI was obtained in the axial plane under free breathing scanning with a multisection, spin-echo type, single-shot echo planar sequence with a body coil. Moreover, the apparent diffusion coefficient (ADC) value was measured in a circular region of interest within the carcinoma, urine, normal bladder wall, prostate, and seminal vesicle. All carcinomas in the 43 patients were clearly shown as high signal intensity relative to the surrounding structure. The sensitivity and positive predictive values of DW MRI were 100% in terms of correctly detecting the carcinomas. The ADC value in the carcinoma (1.40 ± 0.51) was significantly lower compared with that of urine (3.50 ± 0.43) (p < 0.001), normal bladder wall (2.29 ± 0.78) (p < 0.001), peripheral zone of prostate (1.77 ± 0.44) (p < 0.05), transition zone of prostate (1.88 ± 0.54) (p < 0.05), and the seminal vesicle (2.12 ± 0.43) (p < 0.001). There was no statistical difference in ADC values between different histological subtypes. There was no overlap between the ADC values of the tumors and the urine, but there was no clear cutoff between the tumor and bladder wall, prostate, or seminal vesicles. Bladder carcinomas have significantly lower ADC when compared to surroundings. Clinical experience with this method is still preliminary and further studies are required.

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.

Diffusion‐weighted magnetic resonance imaging in follow‐up of superficial urinary bladder carcinoma after transurethral resection: initial experience

Study Type – Diagnostic (exploratory cohort)

Multidetector Computed Tomography: Role in Determination of Urinary Stones Composition and Disintegration With Extracorporeal Shock Wave Lithotripsy—an in Vitro Study

OBJECTIVES To evaluate the ability of noncontrast computed tomography (NCCT) to predict stone composition and fragility for treatment with extracorporeal shock wave lithotripsy (SWL). METHODS A total of 103 stones from patients who had undergone different open surgical procedures were scanned with a 64 detector row helical computed tomography (CT) scanner using 1-mm collimation at 2 energy levels of 80 and 120 kV. The chemical compositions of the urinary stones were assessed on the basis of the differences in the densities measured in Hounsfield units (HU). Stones were then broken in an electromagnetic lithotripter until complete fragmentation, and number of shock waves was counted. RESULTS After exclusion of the groups with few calculi, 46 pure stones (18 uric acid, 22 calcium oxalate monohydrate, 6 struvite) and 48 mixed stones were included in the statistical analysis. For measurements at 120-kV, 80-kV, and dual-energy CT values, the overall difference between the densities of the stones was statistically significant; however there was a cross-over in densities between all stone groups. There were significant positive correlations at 120-kV, 80-kV, and dual-energy CT values between stone density and number of shock waves required for complete fragmentation. Stones with HU >1000 required statistically significant higher number of shock waves. CONCLUSIONS Multidetector CT is not an accurate method for detection of human stone compositions; however a high stone CT attenuation value is s significant predictor of failure to fragment renal stones by SWL.

MRI in patients with chronic obstructive uropathy and compromised renal function: a sole method for morphological and functional assessment

The aim of this study was to assess the role of MRI as a single modality for anatomical and functional evaluation of obstructed kidneys in patients with compromised renal function. The study included 96 adults with unilateral or bilateral chronic obstructive hydronephrosis and compromised renal function (serum creatinine >or=1.8 mg dl(-1)). Patients were subjected to gadolinium-enhanced MRI (Gd-MRI), which determined the anatomy of both renoureteral units, as well as their function, through selective calculation of the glomerular filtration rate (GFR) of each kidney. All patients underwent a technetium-99m diethylenetriamine-pentaacetic acid renal scan. Moreover, a correlation was made between the GFR determined by Gd-MRI and the isotope GFR. The study comprised 59 males and 37 females. A comprehensive MRI study detected the cause of obstruction in all kidneys with non-calcular obstruction (sensitivity of 100%) and in 21 kidneys with calcular obstruction (sensitivity of 70%). The overall sensitivity of MRI combined with plain X-ray of the abdomen and ultrasound in the detection of various causes of obstruction was 97%. A comparison between the isotope GFR of the obstructed kidneys and the corresponding magnetic resonance urography (MRU) GFR showed perfect correlation. In conclusion, combined static and dynamic MRU is a promising technique that allows anatomical and functional evaluation of obstructed kidneys in patients with impaired renal function but, owing to the possible risk of nephrogenic systemic fibrosis in patients with a GFR <30 ml min(-1), the lowest possible dose of the most stable Gd-macrocyclic chelates should be used if a functional MRI study is required.

Radiological diagnosis of vesicouterine fistula: Role of magnetic resonance imaging

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

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

Abstract 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.

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.