The role of imaging in the diagnosis and management of renal stone disease in pregnancy

Comparison of Radiation Exposure for Pregnant Patients Requiring Intervention for Suspected Obstructing Nephrolithiasis

OBJECTIVE

To identify the differences in radiation exposure per suspected stone episode between percutaneous nephrostomy tube (PCN), stent, and primary ureteroscopy (URS).The incidence of nephrolithiasis in pregnancy is low; however, repercussions for both mother and fetus can be significant. In cases of suspected obstructing nephrolithiasis, intervention may be required, including ureteral stent, PCN, or URS, with the potential for multiple subsequent procedures that often utilize fluoroscopy.

METHODS

Pregnant patients who required an intervention (stent, PCN, or URS) for suspected obstructing nephrolithiasis were retrospectively reviewed. The primary outcome was total fluoroscopy exposure per suspected stone episode. Secondary outcomes included fluoroscopic exposure per procedure and number of procedures required.

RESULTS

After excluding patients with renal anomalies and incomplete radiation data, 78 out of 100 patients were included in the analysis. Forty patients (51.3%) underwent initial stent placement, 22 (28.2%) underwent initial PCN placement, and 16 (20.5%) underwent primary URS. Total mean radiation exposure per stone episode was significantly higher in patients who underwent PCN, (286.9 mGy vs 3.7 mGy (stent) and 0.2 mGy (URS), P <.001). In addition, patients who underwent initial PCN placement had significantly more procedures (P <.001) and mean radiation exposure per procedure was higher (P <.001). More than 40% of PCNs experienced dysfunction, and mean duration between PCN exchanges was 16.5 days.

CONCLUSION

In pregnant patients with suspected obstructing nephrolithiasis requiring intervention, initial PCN placement was associated with a significantly higher number of procedures, radiation exposure per procedure, and total radiation exposure per suspected stone episode compared to stent and URS.

Imaging of Acute Abdominopelvic Pain in Pregnancy and Puerperium-Part II: Non-Obstetric Complications

Emergency imaging in pregnancy and puerperium poses unique challenges both for clinicians and radiologists, requiring timely and accurate diagnosis. Delay in treatment may result in poor outcomes for both the patient and the foetus. Pregnant and puerperal patients may present in the emergency setting with acute abdominopelvic pain for various complications that can be broadly classified into obstetric and non-obstetric related diseases. Ultrasonography (US) is the primary diagnostic imaging test; however, it may be limited due to the patient's body habitus and the overlapping of bowel loops. Computed tomography (CT) carries exposure to ionising radiation to the foetus, but may be necessary in selected cases. Magnetic resonance imaging (MRI) is a valuable complement to US in the determination of the etiology of acute abdominal pain and can be used in most settings, allowing for the identification of a broad spectrum of pathologies with a limited protocol of sequences. In this second section, we review the common non-obstetric causes for acute abdominopelvic pain in pregnancy and post partum, offering a practical approach for diagnosis and pointing out the role of imaging methods (US, MRI, CT) with the respective imaging findings.

Differences in management of pregnant women with obstructing infected ureteral stones: A population-based analysis

OBJECTIVES

Obstructing ureteral stones complicated by urinary tract infection are urologic emergencies that require prompt decompression. We explore the association of pregnancy with rates of and delays in decompression in a cohort of women of reproductive age.

METHODS

Using the National Inpatient Sample from 2010 to 2015, a cross-sectional, descriptive analysis of women of reproductive age (15 to 44 years old) diagnosed with obstructing ureteral stones and urinary tract infection was performed and stratified by pregnancy status. Survey-weighted regression models were used to assess the association of pregnancy on decompression, delays in decompression, and hospital length of stay. Additional exploratory analyses on the association of timing and type of decompression with maternal-fetal outcomes were performed.

RESULTS

A weighted total of 38 783 hospitalizations were identified, with 6.1% of admissions occurring in pregnant women. On multivariable regression, pregnant women with obstructing ureteral stones and urinary tract infection were 38% less likely of undergoing decompression (adjusted OR: 0.62; p < 0.001) compared with nonpregnant women. Among those decompressed, pregnant women had greater odds of delayed decompression (adjusted OR: 2.28; p < 0.001) and longer length of stay (adjusted IRR: 1.11; p = 0.007). Delayed decompression among pregnant women was associated with increased rates of C-section, early or threatened labor, fetal distress, and umbilical cord complications.

CONCLUSIONS

Overall, pregnant women had reduced odds of decompression, as well as increased odds of delayed decompression, when compared with nonpregnant women of reproductive age. Delays in decompression among pregnant women were also associated with increased maternal and fetal complications.

Urolithiasis in pregnancy: Advances in imaging modalities and evaluation of current trends in endourological approaches

OBJECTIVE

Given the challenges involved in diagnosis and treatment of pregnant women with urolithiasis, we aim to review the imaging modalities and current endourological management of these patients.

MATERIALS AND METHODS

We performed a review of the available literature on urolithiasis in pregnancy. This included evaluation, diagnostic imaging, and therapeutic options. The databases we searched from included Google Scholar and PubMed. A total of 346 abstracts were screened. After our inclusion/exclusion criteria were met, we were left with 42 sources: 18 retrospective studies, 10 reviews/meta-analyses, 8 sets of guidelines, 5 randomized control trials, and 1 prospective cohort.

RESULTS

We begin our review with the literature available on the safety and efficacy of imaging modalities in the surgical planning for urolithiasis in pregnant patients. This includes renal ultrasound, abdominal x-ray, computed tomography scan, and magnetic resonance imaging. While computed tomography may result in an added radiation exposure, with possible safety concerns, magnetic resonance imaging seems to be safer, however a less sensitive test. We next describe safety, efficacy, and outcomes of various surgical interventions for urolithiasis in pregnant patients. This encompasses ureteral stenting, percutaneous nephrostomy, ureteroscopy, extracorporeal shock wave lithotripsy, and percutaneous nephrolithotomy. Ureteroscopy is a safer approach, but percutaneous nephrolithotomy offers higher stone-free rates. Using an evidence-based approach, we propose an algorithm for management of the pregnant women with renal colic.

CONCLUSION

Management of the pregnant women with suspected urolithiasis is a unique challenge for healthcare providers. A multi-disciplinary approach should be taken to optimize outcomes through an evidence-based approach.

Multimodality Multisystem Imaging of Pregnancy-Related Changes: Featuring Neurologic, Cardiothoracic, Breast, Gynecologic, and Musculoskeletal Issues

ABSTRACT

Pregnancy and the puerperium are a time of significant physiologic change, and with an average of 4 million births in the United States yearly, radiologists encounter pregnancy-related imaging findings regularly. While many of these findings represent physiologic changes, a significant number represent pathology, making it paramount for radiologists to distinguish between the two. This case-based article reviews imaging findings within the nervous, cardiovascular, pulmonary, breast, gynecologic, musculoskeletal, digestive, hematologic, and integumentary systems throughout pregnancy and the postpartum period.

Risk factors of uterine contraction after ureteroscopy in pregnant women with renal colic

Background

Ureteroscopy is widely applied in pregnant women with renal colic, but such patients are easy to experience uterine contraction after surgery. There are many factors which may affect uterine contraction, this study aims to explore the risk factors of uterine contraction triggered by ureteroscopy in pregnant women with renal colic.

Methods

One hundred and one pregnant women were retrospectively analyzed, the patients were hospitalized because of severe renal colic. All patients received ureteroscopy during which double J catheters were inserted into ureters for drainage. Patients received other medical treatments individually according to their condition and uterine contractions were detected by EHG within 12 h after operation. Patients were classified as group A (uterine contraction) and group B (no uterine contraction) according to the presence or absence of continuously regular uterine contraction. Clinical characteristics were collected for further analysis, including history of childbirth, anesthesia method, application of phloroglucinol or not, operation time, Oxygen inhalation or not, pain relief or not after surgery, systemic inflammatory response syndrome (SIRS) occurred or not. A binary logistic regression analysis model was established to explore whether such clinical characteristics were relevant to uterine contraction after ureteroscopy.

Results

Continuously regular uterine contraction presented in 46 pregnant women within 12 h after ureteroscopy, making the incidence of uterine contraction as high as 45.54%. The presence of uterine contraction was related to the following factors(P < 0.05): history of childbirth (primipara versus multipara)(OR 6.593, 95% CI 2.231–19.490), operation time (each quarter additional) (OR 2.385, 95% CI 1.342–4.238), application of phloroglucinol (yes versus not) (OR 6.959, 95% CI 1.416–34.194), pain relief after surgery(yes versus not)(OR 6.707, 95% CI 1.978–22.738), SIRS occurred after surgery (yes versus not) (OR 0.099, 95% CI 0.014–0.713).

Conclusion

Continuously regular uterine contraction is easy to occur within 12 h after ureteroscopy in pregnant women. SIRS occurred after surgery is a risk factor for uterine contraction; on the contrary, no history of childbirth, shorter operation time, application of phloroglucinol, pain relief after surgery are protective factors.

Kidney Imaging and Biopsy in Pregnancy

Physiologic glomerular, tubular, and structural changes related to pregnancy may complicate the detection of underlying kidney disease in pregnant patients. Imaging studies may provide important clinical information to assist in the diagnosis and treatment of kidney disease during pregnancy. Furthermore, in select patients who develop new or worsening kidney disease in pregnancy, kidney biopsy may be essential to ensure the accuracy of diagnosis and guide treatment choices. This review article will discuss the risks and benefits of various modalities used to image the kidneys and urinary tract during pregnancy to aid in the judicious selection of appropriate imaging studies that are likely to maximize clinical benefit while minimizing fetal risk. It will also highlight the potential benefits and harms associated with antepartum kidney biopsy and will offer strategies for identifying patients who are most likely to benefit from kidney biopsy during pregnancy.

Detection of distal ureteral stones in pregnancy using transvaginal ultrasound

AIMS

To determine the performance of transvaginal ultrasound for the visualization of distal ureteral stones in pregnant patients with renal colic and to evaluate the diagnostic value of secondary findings suggestive of obstructing ureteral stone disease.

METHODS

We retrospectively identified 129 pregnant patients with a total of 142 encounters with both abdominal and transvaginal ultrasound. Ultrasound images for each patient were reviewed recording the presence of stone with location, hydronephrosis, resistive indices (RI), and status of the ureteral jets. Patients were subcategorized into two groups based on the visualization of distal ureteral stone.

RESULTS

The transvaginal technique identified 94% (N = 16/17) of sonographically detected stones in the distal ureter/urethra, while the transabdominal technique identified 29% (N = 5/17). The combined imaging for initial assessment of renal colic in pregnancy demonstrated a sensitivity of 89%, specificity 100%, and negative predictive value (NPV) of 98%. The frequency of hydronephrosis was statistically greater in the visualized stone group (94% vs 51%). Mean RI was identical in both groups however the delta RI was significantly elevated in those patients with distal ureteral stones with a mean delta RI value of 0.05. The rate of absence of ureteral jets was not statistically significant.

CONCLUSION

The present data would suggest a utility of transvaginal ultrasound for the evaluation of the pregnant patient with 94% of distal stones being detected transvaginal versus 29% transabdominally. Additionally, there was significantly increased hydronephrosis and elevated RIs in patients with distal ureteral stones.

Infectious and Inflammatory Diseases of the Urinary Tract: Role of MR Imaging

Urinary tract infection (UTI) is among the most common of bacterial infections. Imaging studies are only required in cases of complicated UTIs. Ultrasound remains the first-line imaging method; however, CT is the gold standard for evaluation of UTIs. MR imaging's improved contrast resolution and absence of ionizing radiation may recommend its use for assessment of lower UTIs. Furthermore, MR imaging performs with diagnostic accuracy at least similar to CT in complicated UTIs, except for the identification of calculi and emphysematous pyelonephritis. In this article, the role of MR imaging for the evaluation of infectious and inflammatory disease processes of the urinary tract is reviewed.

Urinary Stone Disease: Diagnosis, Medical Therapy, and Surgical Management

Clinical suspicion of urolithiasis should be evaluated with low-dose computed tomography as the first-line imaging modality for nonpregnant, adult patients. A period of observation may be appropriate for ureteral stones less than 10 mm, and medical expulsive therapy may be beneficial for facilitating passage of distal ureteral stones. Regardless of stone type, patients should adhere to a low-sodium diet and attempt to achieve a urine volume of more than 2.5 L daily. Individuals with calcium stones should maintain a normal calcium diet, and if stones persist, citrate therapy or thiazide diuretics in the setting of hypercalciuria may be indicated.

Imaging of flank pain: readdressing state-of-the-art

Pain resulting from renal and ureteral stones is a common cause for patients presenting in the acute setting. Since the late 1990s, computed tomography (CT) has been the initial imaging method of choice to evaluate patients with suspected ureteral stones; however, concerns regarding both radiation dose and cost-effectiveness have prompted investigations into a different imaging algorithm. Studies utilizing ultrasound have provided evidence indicating that it may be a more appropriate first step, with selective use of CT in selected cases, in the diagnostic work-up. Techniques have evolved with low-dose CT, dual-energy CT, and magnetic resonance urography emerging as useful in imaging of renal colic patients. This manuscript reviews the current literature on state-of-the-art imaging for acute flank pain and proposes a new imaging algorithm in the evaluation of patients with acute flank pain and suspected ureteral stones.