Comparison of high-field magnetic resonance imaging with computed tomography in the evaluation of blunt renal trauma

Role of MRI in early follow-up of patients with solid organ injuries: How and why we do it?

Trauma represents one of the most common causes of death or permanent disability in the population below 50 years. At present, non-operative treatment is the commonly adopted strategy in hemodynamically stable patients with solid organ injuries, when there are not concomitant bowel and mesenteric injuries requiring a prompt surgical approach, but it may require multiple imaging follow-up examinations, especially in the case of major injuries. No data are available about magnetic resonance imaging utilization in the early follow-up of trauma patients with solid organ injuries, particularly in liver and spleen trauma. We report our preliminary experience in this field.

Renal trauma imaging: Diagnosis and management. A pictorial review

BACKGROUND

The purpose of this review is to illustrate and discuss the spectrum of imaging findings, particularly computed tomography (CT), of blunt and penetrating renal trauma, based on our own materials, according to the American Association for Surgery of Trauma (AAST) renal injury grading scale. The article also indicates the conditions in which interventional radiology procedures can be applied for the management of renal trauma.

MATERIAL/METHOD

Cases for this pictorial review were selected from the imaging material collected at the Radiology Department of Hamad Medical Corporation during a 14-year period from 1999 to 2012. The material includes 176 cases (164 males and 12 females) with confirmed blunt or penetrating renal trauma. Following abdominal trauma, all patients had a CT examination performed on admission to the hospital and/or during hospitalization. The most representative and illustrative cases of renal trauma were reviewed according to CT findings and were categorized according to the AAST grading system.

DISCUSION

The review describes a spectrum of imaging presentations with special emphasis on the 5 grades of renal injury on a CT according to the AAST scale. The most representative cases were illustrated and discussed with indications of possible interventional radiology treatment. Two groups of patients not included in the AAST grading system were presented separately: those with preexisting renal abnormalities and those with sustained iatrogenic renal injury.

CONCLUSIONS

Proper application of renal trauma grading scale is essential for selecting the patients for conservative treatment, surgery or interventional radiology procedure.

Late evaluation of the relationship between morphological and functional renal changes and hypertension after non-operative treatment of high-grade renal injuries

Objective

To evaluate the anatomical and functional renal alterations and the association with post-traumatic arterial hypertension.

Methods

The studied population included patients who sustained high grades renal injury (grades III to V) successfully non-operative management after staging by computed tomography over a 16-year period. Beyond the review of medical records, these patients were invited to the following protocol: clinical and laboratory evaluation, abdominal computed tomography, magnetic resonance angiography, DMSA renal scintigraphy, and ambulatory blood pressure monitoring. The hypertensive patients also were submitted to dynamic renal scintigraphy (^99mTc EC), using captopril stimulation to verify renal vascular etiology.

Results

Of the 31 patients, there were thirteen grade III, sixteen grade IV (nine lacerations, and seven vascular lesions), and two grade V injuries. All the patients were asymptomatic and an average follow up post-injury of 6.4 years. None had abnormal BUN or seric creatinine. The percentage of renal volume reduction correlates with the severity as defined by OIS. There was no evidence of renal artery stenosis in Magnetic Resonance angiography (MRA). DMSA scanning demonstrated a decline in percentage of total renal function corresponding to injury severity (42.2 ± 5.5% for grade III, 35.3 ± 12.8% for grade IV, 13.5 ± 19.1 for grade V). Six patients (19.4%) had severe compromised function (< 30%). There was statistically significant difference in the decrease in renal function between parenchymal and vascular causes for grade IV injuries (p < 0.001). The 24-hour ambulatory blood pressure monitoring detected nine patients (29%) with post-traumatic hypertension. All the patients were male, mean 35.6 years, 77.8 % had a familial history of arterial hypertension, 66.7% had grade III renal injury, and average post-injury time was 7.8 years. Seven patients had negative captopril renography.

Conclusions

Late results of renal function after conservative treatment of high grades renal injuries are favorable, except for patients with grades IV with vascular injuries and grade V renal injuries. Moreover, arterial hypertension does not correlate with the grade of renal injury or reduction of renal function.

Traumatic urologic injuries in Ile-Ife, Nigeria

Background:

In a developing country with limited healthcare resources, traumatic injuries and their management pose a significant challenge to healthcare delivery.

Aim:

To highlight the challenges in the management of traumatic urologic injuries in patients in our setting.

Setting and Design:

Patients presenting with traumatic injuries to the urinary tract, between January 1996 and December 2005, in a University Teaching Hospital in Southwestern Nigeria were the subjects of this study.

Patients and Methods:

Clinical records of patients who had such injuries were reviewed.

Results:

Ninety injuries occurred in 86 patients including 77 males and 9 females aged 14–68 years. Fourteen (15.5%) of the injuries involved the kidneys, urinary bladder was involved in 23 (25.6%) and the male urethra in 53 (58.9%) injuries. The mechanisms of injury were road traffic accidents in 52 (60.5%) patients, straddle injuries in 18 (20.9%), trauma to the back in 8 (9.3%), falls from a height in 6 (7.0%) and gunshot injuries in 2 (2.3%) patients. Associated injuries include pelvic fractures in 33 (38.4%) patients, limb bone fractures in 13 (14.1%), intestinal injuries in 12 (13.0%) and spinal injuries in 8 (8.7%) patients. In most patients, diagnosis was made based on clinical suspicion and minimal investigations such as abdominal ultrasound, urethrocystoscopy and/or urethrocystography. The outcome was good in most patients and mortality was recorded in only 2 (2.3%) patients who had concomitant spinal and burns injuries.

Conclusion:

Prompt management instituted on clinical suspicion of injuries presents a good outcome in patients in a limited resource setting.

Abordagem do trauma renal - artigo de revisão: review of the literature

A incidência de traumatismo é uma realidade crescente nos dias de hoje. O acometimento dos reina ocorre em cerca de 10% dos pacientes com trauma abdominal fechado ou penetrante, podendo elevar muito a morbimortalidade quando não bem conduzido. Os autores fizeram um levantamento de artigos recentes para esclarecimentos no diagnóstico e na conduta no traumatismo renal, desde os detalhes anatômicos até o tratamento definitivo. A correta condução do paciente é fundamental para a preservação e manutenção da função do órgão, sobretudo da vida, após o evento traumático.

Renal Injury: 5-Year Experience and Literature Review

INTRODUCTION

Appropriate management of renal trauma is controversial. The purpose of this study is to present our 5-year experience in renal trauma and review the literature.

MATERIALS AND METHODS

From 1999 to 2003, 28 patients were identified with renal injuries. 25 (89.3%) of the injuries were caused by blunt trauma, 2 (7.1%) by stab wounds, and 1 (3.6%) by gunshot wound. Methods for diagnosis included ultrasonography (US), computed tomography (CT), diagnostic peritoneal lavage (DPL), combinations of more than one technique or no one of them. The English-language literature about renal trauma was also identified using Medline, and additional cited works not detected in the initial search obtained.

RESULTS

18 patients underwent immediate or during 24 h operation; while 5 nephrectomies were performed. 11 patients with grade I to III injuries were selected for nonoperative management of renal injuries. All complications were noted and studied according to the initial therapeutic management and grade. Follow-up was clinical and radiological. 3 postoperative deaths were observed.

CONCLUSION

The goals of treatment of renal injuries include accurate staging and minimal complications. Surgery can be avoided in most cases of blunt renal injury but there is also a trend towards conservative management of penetrating trauma. Nephrectomy is associated with high-grade renal injuries, while minor renal injuries can safely be managed conservatively.

Evaluation and management of renal injuries: consensus statement of the renal trauma subcommittee

OBJECTIVE

To determine the optimal evaluation and management of renal injuries by review of the world's English-language literature on the subject.

METHODS

A consensus conference convened by the World Health Organization and the Societé Internationale d'Urologie met to critically review reports of the diagnosis and treatment of renal trauma. The English-language literature about renal trauma was identified using Medline, and additional cited works not detected in the initial search obtained. Evidence-based recommendations for the diagnosis and management of renal trauma were made with reference to a five-point scale.

RESULTS

There were many Level 3 and 4 citations, few Level 2, and one Level 1 which supported clinical practice patterns. Findings of nearly 200 reviewed citations are summarized.

CONCLUSIONS

Published reports on renal trauma still rely heavily on expert opinion and single-institution retrospective case series. Prospective trials of the most significant issues, when possible, might improve the quality of evidence that dictates the behaviour of practitioners.

Imaging of renal trauma: a comprehensive review

Computed tomography (CT) is the modality of choice in the evaluation of blunt renal injury. Intravenous urography is used primarily for gross assessment of renal function in hemodynamically unstable patients. Selective renal arteriography or venography can provide detailed information regarding vascular injury. Retrograde pyelography is valuable in assessing ureteral and renal pelvic integrity in suspected ureteropelvic junction injury. Ultrasonography is useful in detecting hemoperitoneum in patients with suspected intraperitoneal injury but has limited value in evaluating those with suspected extraperitoneal injury. Occasionally, radionuclide renal scintigraphy or magnetic resonance imaging may prove helpful. Renal injuries can be classified into four large categories based on imaging findings. Category I renal injuries include minor cortical contusion, subcapsular hematoma, minor laceration with limited perinephric hematoma, and small cortical infarct. Category II lesions include major renal lacerations extending to the medulla with or without involvement of the collecting system and segmental renal infarct. Category III lesions are catastrophic renal injuries and include multiple renal lacerations and vascular injury involving the renal pedicle. Category IV injuries are ureteropelvic junction injuries. CT is particularly useful in evaluating traumatic injuries to kidneys with preexisting abnormalities and can help assess the extent of penetrating injuries in selected patients with limited posterior stab wounds. Integration of the imaging findings in renal injury with clinical information is critical in developing a treatment plan.

Is there a role for magnetic resonance imaging in renal trauma?

BACKGROUND

Computed tomography (CT) has been the most informative imaging method in renal trauma. Despite the good sensitivity of magnetic resonance imaging (MRI) to the presence of hematoma, edema and ischemia, MRI has not been widely studied in patients with renal trauma. The present study was initiated to evaluate the role of MRI in patients with renal trauma.

METHODS

Between June 1998 and September 1999, CT and MRI were prospectively performed on 12 patients who suffered from renal trauma and the results reviewed.

RESULTS

The presence and size of perirenal hematoma could be detected by both CT and MRI. Magnetic resonance imaging could differentiate intrarenal hematoma from perirenal hematoma more accurately, and provided additional information about the hematoma as T1- and T2-weighted MRI were able to determine recent bleeding in the hematoma by regional differences in signal intensity. Magnetic resonance imaging clearly revealed renal fracture with non-viable fragment and detected focal renal laceration that was not detected on CT due to perirenal hematoma associated with renal infarction. However, although MRI had many advantages over CT, it had also major drawbacks, which were that it required longer imaging time and increased the cost.

CONCLUSIONS

Magnetic resonance imaging may be useful in renal trauma. However, it is suggested that MRI should be limited to carefully selected patients, such as those with severe renal injury or equivocal findings on CT.

Radiologic Evaluation of Renal Trauma: Part 2

Imaging of the kidneys and upper urinary tract has traditionally relied upon the administration of intravascular, iodine-based radiographic contrast agents. These contrast agents are not without drawbacks, however, and may cause renal damage, cardiopulmonary dysfunction, and allergic-type reactions. Computed tomography (CT) has largely replaced the “single shot” intravenous urogram (IVU), except in unstable patients, because of the ability to accurately and rapidly delineate the majority of significant renal injuries. Renal contusions, intra- and extrarenal hematomas, renal lacerations and fractures, and urinary extravasation all can be reliably depicted with CT. The extent of parenchymal injury, minor laceration versus “shattered” kidney, as well as the size of a hematoma or collecting system injury are critical in determining whether urgent intervention is required or expectant management can be instituted. Extravasation of intravascular contrast on CT is an important clue to significant, ongoing bleeding. Further evaluation with angiography is usually indicated in this case, with the additional benefit that transcatheter embolization may be curative. Other imaging modalities such as ultrasonography, magnetic resonance imaging, and nuclear medicine can be considered for patients with a history of intravenous contrast allergy or preexisting renal dysfunction. These latter modalities also assume more important roles in the follow-up of patients with posttraumatic renal tissue loss or hypertension.

MRI and CT in blunt renal trauma: an update

In our experience, MRI is as effective as CT in correctly staging renal injury. The coronal and sagittal slice orientations of MRI are particularly helpful in determining the extent of the renal parenchymal damage. Both methods are accurate in finding perirenal hematomas, assessing the viability of renal fragments, and detecting preexisting renal abnormalities but are relatively inaccurate in visualizing urinary extravasation. Although CT remains the method of choice in radiological staging of renal injury, MRI can complement CT in patients with severe renal injury, preexisting renal abnormality, equivocal CT findings, or when repeated radiological follow-up is required. MRI could replace CT in patients with iodine allergy and be used for initial staging if CT is not available.