Gadolinium-Based Contrast Agents: Updates and Answers to Typical Questions Regarding Gadolinium Use.

Gadolinium-based contrast agents have expanded the diagnostic usefulness and capability of magnetic resonance imaging. Despite their highly favorable safety profile, these agents have been associated with nephrogenic systemic fibrosis in a small number of patients who have advanced kidney disease. Recently, trace amounts of gadolinium deposition in the brain and other organs have been reported after contrast exposure, even in patients with normal renal function. In this review, we provide a brief overview of recent updates and discuss typical clinical situations related to the use of gadolinium-based contrast agents.

A gravity-assisted approach to the management of urinary diversion: 99mTc-MAG3 diuresis renography with F + 10(sp) method.

OBJECTIVE: Radical cystectomy with permanent urinary diversion is the gold standard treatment for invasive muscle bladder cancer. Hydronephrosis is common in these patients, but Ultrasound (US) or Computed Tomography Urography (CTU) scan are unable to discriminate obstructive from non-obstructive hydronephrosis. We used Diuresis Renography (DR) with F + 10 in seated position (sp) method in the identification of patients with a Uretero-ileal Anastomosis Stricture (UAS) who would benefit from surgical therapy. METHODS: We studied 39 asymptomatic patients, who underwent radical cystectomy and urinary diversion. Based on radiological findings (US, CTU) 44 kidneys were hydronephrotic. All patients underwent a 99mTc-MAG3 DR with F + 10(sp) method. We acquired a DR for 20 min with the patient in a seated position. Patient drank 400-500 mL of water at 5 min after tracer injection and received a 20 mg bolus of Furosemide at 10 min during dynamic acquisition. The indices Time to peak, diuretic half time, and 20 min/peak ratio have been evaluated. Retrograde pyelography confirmed UAS in all patients with DR obstructive findings. We repeated DR as follow-up in two subgroups of patients. RESULTS: DR with F + 10(sp) method showed obstructive findings in 36 out of 44 hydronephrotic kidneys. 6 patients showed non-obstructive findings. 32 patients showed obstructive findings (20 out of 32 developed UAS within 12 months after surgery). Fifteen pts underwent a surgical treatment of UAS. In 1 patient with equivocal findings, we observed an ileo-ureteral reflux. CONCLUSIONS: The DR with F + 10(sp) method in the seated position has a lower uncertain diagnostic rate, compared to the radiological findings of US or CTU, in management of bladder cancer patients with urinary diversion. The semiquantitative indices diuretic half time and 20 min/peak ratio evaluated in a condition of favorable gravity reduce uncertain responses improving interobserver concordance.

Proposal for computer-aided diagnosis based on ultrasound images of the kidney: is it possible to compare shades of gray among such images?

OBJECTIVE: To compare ultrasound images of the kidney obtained, randomly or in a controlled manner (standardizing the physical aspects of the ultrasound system), by various professionals and with different devices. MATERIALS AND METHODS: We evaluated a total of 919 images of kidneys, obtained by five professionals using two types of ultrasound systems, in 24 patients. The images were categorized into four types, by how they were acquired and processed. We compared the gray-scale median and different gray-scale ranges representative of virtual histological tissues. RESULTS: There were statistically significant differences among the five professionals, regardless of the type of ultrasound system employed, in terms of the gray-scale medians for the images obtained (p < 2.2e-16). Analyzing the four categories of images-a totally random image (without any standardization); a standardized image (with fixed values for gain, time gain control, and dynamic range); a normalized version of the random image; and a normalized version of the standardized image-we determined that the random image, even after normalization, differed quite significantly among the professionals (p = 0.006098). The analysis of the normalized version of the standardized image did not differ significantly among the professionals (p = 0.7319). CONCLUSION: Our findings indicate that a gray-scale analysis of ultrasound images of the kidney performs better when the image acquisition process is standardized and the images undergo a process of normalization.

OBJETIVO: Comparar imagens renais ultrassonográficas obtidas de maneira aleatória e controlada (padronizando fatores físicos do aparelho de ultrassom) por diferentes profissionais e aparelhos. MATERIAIS E MÉTODOS: Foram obtidos quatro tipos de imagens, de acordo com sua aquisição e processamento por cinco profissionais e dois tipos de aparelhos de ultrassonografia, em 24 pacientes, totalizando 919 imagens. Comparamos a mediana de escala de cinza e diferentes intervalos de tons de cinza representantes de tecidos histológicos virtuais. RESULTADOS: As medianas de escala de cinza de imagens renais obtidas por dois tipos de aparelhos foram estatisticamente diferentes (p < 2.2e-16). Analisando os quatro tipos de imagens, partindo de uma totalmente aleatória (sem qualquer padronização), uma padronizada (fixado o ganho, time gain control e dynamic range), e essas duas passando por um processo de normatização, obteve-se que a imagem aleatória é totalmente diversa entre os profissionais (p = 0,006098), mesmo passando pelo processo de normatização. A imagem padronizada, após passar pelo processo de normatização, apresentou resultados equivalentes, não possuindo diferença estatística (p = 0,7319). CONCLUSÃO: Constatou-se que na análise de tons de cinza deve-se usar um mesmo tipo de máquina e uma imagem em que sejam padronizados aspectos físicos, passando por um processo de normatização/padronização.

Proposal for computer-aided diagnosis based on ultrasound images of the kidney: is it possible to compare shades of gray among such images? / Proposição de um diagnóstico auxiliado por computador de imagem renal ultrassonográfica: é possível comparar tons de cinza das imagens ultrassonográficas renais?

Abstract Objective: To compare ultrasound images of the kidney obtained, randomly or in a controlled manner (standardizing the physical aspects of the ultrasound system), by various professionals and with different devices. Materials and Methods: We evaluated a total of 919 images of kidneys, obtained by five professionals using two types of ultrasound systems, in 24 patients. The images were categorized into four types, by how they were acquired and processed. We compared the gray-scale median and different gray-scale ranges representative of virtual histological tissues. Results: There were statistically significant differences among the five professionals, regardless of the type of ultrasound system employed, in terms of the gray-scale medians for the images obtained (p < 2.2e-16). Analyzing the four categories of images-a totally random image (without any standardization); a standardized image (with fixed values for gain, time gain control, and dynamic range); a normalized version of the random image; and a normalized version of the standardized image-we determined that the random image, even after normalization, differed quite significantly among the professionals (p = 0.006098). The analysis of the normalized version of the standardized image did not differ significantly among the professionals (p = 0.7319). Conclusion: Our findings indicate that a gray-scale analysis of ultrasound images of the kidney performs better when the image acquisition process is standardized and the images undergo a process of normalization.

Resumo Objetivo: Comparar imagens renais ultrassonográficas obtidas de maneira aleatória e controlada (padronizando fatores físicos do aparelho de ultrassom) por diferentes profissionais e aparelhos. Materiais e Métodos: Foram obtidos quatro tipos de imagens, de acordo com sua aquisição e processamento por cinco profissionais e dois tipos de aparelhos de ultrassonografia, em 24 pacientes, totalizando 919 imagens. Comparamos a mediana de escala de cinza e diferentes intervalos de tons de cinza representantes de tecidos histológicos virtuais. Resultados: As medianas de escala de cinza de imagens renais obtidas por dois tipos de aparelhos foram estatisticamente diferentes (p < 2.2e-16). Analisando os quatro tipos de imagens, partindo de uma totalmente aleatória (sem qualquer padronização), uma padronizada (fixado o ganho, time gain control e dynamic range), e essas duas passando por um processo de normatização, obteve-se que a imagem aleatória é totalmente diversa entre os profissionais (p = 0,006098), mesmo passando pelo processo de normatização. A imagem padronizada, após passar pelo processo de normatização, apresentou resultados equivalentes, não possuindo diferença estatística (p = 0,7319). Conclusão: Constatou-se que na análise de tons de cinza deve-se usar um mesmo tipo de máquina e uma imagem em que sejam padronizados aspectos físicos, passando por um processo de normatização/padronização.

Progression rate in Bosniak category IIF complex renal cysts.

OBJECTIVE: To evaluate progression rate of Bosniak category IIF complex renal cysts and the malignancy rate among surgically resected cysts. MATERIALS AND METHODS: We performed a database search for complex renal cysts classified as Bosniak category IIF on computed tomography or magnetic resonance imaging between January 2008 and April 2016. Follow-up examinations (computed tomography or magnetic resonance imaging) were used in order to evaluate progression (Bosniak category reclassification) and stability, the latter being defined as remaining stable for a minimum of six months. Pathology reports were used as the reference to assess the malignancy rate of surgically resected cysts. RESULTS: A total of 152 cysts in 143 patients were included in the final analysis. Seven cysts (4.6%) were reclassified on follow-up studies, and mean time to progression was 20 months (range, 1 month to 4 years). Three cysts were surgically resected. All three were diagnosed as low-grade malignant renal cell carcinomas (RCCs): one clear cell RCC and two papillary RCCs. The remaining 145 cysts remained unchanged after a mean follow-up period of 28 months (range, 6 to 118 months). CONCLUSION: The progression rate in Bosniak category IIF cysts was low. Even lesions that were upgraded on follow-up remained stable, indicating an indolent behavior. Our data support the idea of conservative management of Bosniak IIF renal cyst.

OBJETIVO: Avaliar a taxa de progressão das lesões císticas renais complexas Bosniak II-F e a taxa de neoplasia maligna nas lesões ressecadas cirurgicamente. MATERIAIS E MÉTODOS: Realizamos uma pesquisa no banco de dados da nossa instituição reunindo lesões císticas renais complexas classificadas como Bosniak II-F em exames de tomografia computadorizada ou ressonância magnética, de janeiro de 2008 a abril de 2016. Foram utilizados exames de acompanhamento (tomografia computadorizada ou ressonância magnética) para avaliar a progressão na categoria Bosniak, com um mínimo de seis meses de estabilidade. Os relatórios de patologia foram utilizados como referência para avaliar a taxa de neoplasia maligna de lesões ressecadas cirurgicamente. RESULTADOS: Um total de 152 lesões em 143 pacientes foi incluído na análise final. Sete lesões foram reclassificadas em estudos de acompanhamento (4,6%) e o tempo médio de progressão foi de 20 meses (1 mês a 4 anos). Três pacientes tiveram cistos ressecados cirurgicamente, todos diagnosticados como carcinoma de células renais: um do subtipo células claras e dois papilíferos, todos de baixo grau. As 145 lesões restantes permaneceram inalteradas, com seguimento médio de 28 meses (6 a 118 meses). CONCLUSÃO: A taxa de progressão nos cistos categoria Bosniak II-F foi baixa. Mesmo as lesões que tiveram upgrade da categoria de Bosniak no seguimento permaneceram estáveis, indicando um comportamento indolente. Nossos dados apoiam a ideia de tratamento conservador do cisto renal Bosniak II-F.

Progression rate in Bosniak category IIF complex renal cysts / Taxa de progressão de lesões císticas renais complexas Bosniak II-F

Abstract Objective: To evaluate progression rate of Bosniak category IIF complex renal cysts and the malignancy rate among surgically resected cysts. Materials and Methods: We performed a database search for complex renal cysts classified as Bosniak category IIF on computed tomography or magnetic resonance imaging between January 2008 and April 2016. Follow-up examinations (computed tomography or magnetic resonance imaging) were used in order to evaluate progression (Bosniak category reclassification) and stability, the latter being defined as remaining stable for a minimum of six months. Pathology reports were used as the reference to assess the malignancy rate of surgically resected cysts. Results: A total of 152 cysts in 143 patients were included in the final analysis. Seven cysts (4.6%) were reclassified on follow-up studies, and mean time to progression was 20 months (range, 1 month to 4 years). Three cysts were surgically resected. All three were diagnosed as low-grade malignant renal cell carcinomas (RCCs): one clear cell RCC and two papillary RCCs. The remaining 145 cysts remained unchanged after a mean follow-up period of 28 months (range, 6 to 118 months). Conclusion: The progression rate in Bosniak category IIF cysts was low. Even lesions that were upgraded on follow-up remained stable, indicating an indolent behavior. Our data support the idea of conservative management of Bosniak IIF renal cyst.

Resumo Objetivo: Avaliar a taxa de progressão das lesões císticas renais complexas Bosniak II-F e a taxa de neoplasia maligna nas lesões ressecadas cirurgicamente. Materiais e Métodos: Realizamos uma pesquisa no banco de dados da nossa instituição reunindo lesões císticas renais complexas classificadas como Bosniak II-F em exames de tomografia computadorizada ou ressonância magnética, de janeiro de 2008 a abril de 2016. Foram utilizados exames de acompanhamento (tomografia computadorizada ou ressonância magnética) para avaliar a progressão na categoria Bosniak, com um mínimo de seis meses de estabilidade. Os relatórios de patologia foram utilizados como referência para avaliar a taxa de neoplasia maligna de lesões ressecadas cirurgicamente. Resultados: Um total de 152 lesões em 143 pacientes foi incluído na análise final. Sete lesões foram reclassificadas em estudos de acompanhamento (4,6%) e o tempo médio de progressão foi de 20 meses (1 mês a 4 anos). Três pacientes tiveram cistos ressecados cirurgicamente, todos diagnosticados como carcinoma de células renais: um do subtipo células claras e dois papilíferos, todos de baixo grau. As 145 lesões restantes permaneceram inalteradas, com seguimento médio de 28 meses (6 a 118 meses). Conclusão: A taxa de progressão nos cistos categoria Bosniak II-F foi baixa. Mesmo as lesões que tiveram upgrade da categoria de Bosniak no seguimento permaneceram estáveis, indicando um comportamento indolente. Nossos dados apoiam a ideia de tratamento conservador do cisto renal Bosniak II-F.

[Experience in the conservative treatment of renal trauma]. / Experiencia en el tratamiento conservador del traumatismo renal.

OBJECTIVE: The management of renal trauma has been changing in recent years so that nowadays, even in high grades, an initial conservative treatment is advocated. The aim of this work is to review the presentation, initial attitude and evolution of the renal traumas treated in our institution. MATERIAL AND METHODS: Retrospective review of patients with renal trauma treated at our institution in the last 10 years. Epidemiological variables, production mechanism, pediatric trauma index (PTI), treatment and evolution were analyzed. RESULTS: We studied 26 patients, 18 men (69.3%). The most frequent mechanism was the direct hit in 11 patients (42.31%). The most frequently side affected was the right one in 14 patients (53.85%). The grade III traumatism according to American Association for the surgery of Trauma (AAST) was the most repeated, 11 patients (42.31%). Nine patients (44.55%) presented concomitant injuries in other solid organs. In 24 patients (92.30%) the initial treatment was conservative with supportive measures. One patient presented with hemodynamic instability and an urgent intervention was conducted, performing a supraselective embolization with immediate control of the active bleeding. In another patient, a double J catheter was placed due to disruption of the excretory tract. Of the patients treated conservatively initially, only one patient (4.1%) required secondary surgical maneuvers due to a complication. CONCLUSIONS: In patients with renal trauma, non-surgical treatment is safe and effective. In case of hemodynamic instability or complication, interventional radiological techniques have been demonstrated to be safe and effective in the pediatric population.

OBJETIVO: El manejo del traumatismo renal ha ido variando en los últimos años de modo que en la actualidad, incluso en los grados altos, se aboga por un tratamiento inicial conservador. El objetivo de este trabajo es revisar la presentación, actitud inicial y evolución de los traumatismos renales atendidos en nuestra institución. MATERIAL Y METODOS: Revisión retrospectiva de pacientes con traumatismo renal atendidos en los últimos 10 años. Se analizaron las variables epidemiológicas, mecanismo de producción, índice de trauma pediátrico (ITP), tratamiento y evolución. RESULTADOS: Se estudiaron 26 pacientes, 18 varones (69,23%). La causa más frecuente fue el golpe directo en 11 pacientes (42,31%). El lado más frecuentemente afectado fue el derecho en 14 pacientes (53,85%). El traumatismo grado III según la American Association for the Surgery of Trauma (AAST) fue el más común, 11 pacientes (42,31%). Nueve pacientes (44,55%) presentaron lesiones concomitantes en otros órganos sólidos. En 24 pacientes (92,30%) el tratamiento inicial fue conservador con medidas de soporte. Un paciente se presentó con inestabilidad hemodinámica y se intervino de forma urgente realizándose embolización supraselectiva con control inmediato del sangrado activo. En otro paciente se colocó un catéter doble J por disrupción de la vía excretora. De los pacientes tratados de manera conservadora inicialmente solo 1 paciente (4,1%) requirió maniobras quirúrgicas secundarias debido a una complicación. CONCLUSIONES: En pacientes con traumatismo renal el tratamiento no quirúrgico es seguro y eficaz. En caso de inestabilidad hemodinámica o complicación, las técnicas radiológicas intervencionistas han demostrado ser seguras y efectivas en la edad pediátrica.