Stone disease in pregnancy: imaging-guided therapy

Zero-echo time MRI: an alternative method for the diagnosis of urinary stones in children

OBJECTIVES

To evaluate the potential of zero-echo time-magnetic resonance imaging (ZTE-MRI) in the assessment of urolithiasis and compare ZTE-MRI with computed tomography (CT) in pediatric patients.

MATERIALS AND METHODS

This was a single-center, prospective cross-sectional study conducted between April 2023 and December 2023. 23 patients (12 girls, 11 boys; mean age: 12.3, range 1-18) with urinary tract stones detected on non-enhanced abdominal CT were enrolled. The images were evaluated independently by two radiologists for the presence, and number of stones in the kidneys, ureters, and bladder. In the second session, two radiologists evaluated whether urinary tract stones could be detected by MRI compared to CT, and the maximum diameter of the stones was measured. The CT and MRI results were compared with the Wilcoxon test. The agreement between the results of the observers was examined using Spearman's rho correlation coefficient and the intraclass correlation coefficient.

RESULTS

A total of 58 urinary tract stones were detected by CT and 39 of these were detected by MRI. Most of the stones that MRI could not detect were < 5 mm and the detection sensitivity of MRI increased in correlation with stone size (p < 0.001). There was poor intermodality agreement for stones < 5 mm, substantial agreement for stones 5-10 mm, and almost perfect agreement for stones > 10 mm. Interobserver agreement for stone detection on MRI was almost perfect for stones > 10 mm and 5-10 mm and was substantial for stones < 5 mm.

CONCLUSION

ZTE-MRI is a promising modality for detecting urinary stones without radiation exposure in children.

CLINICAL RELEVANCE STATEMENT

Zero-echo time-magnetic resonance imaging is a potential method for identifying urinary stones in children and other populations who are particularly sensitive to radiation.

KEY POINTS

Urinary system stone disease in children is increasing and imaging is needed for managing urolithiasis. Zero-echo time-magnetic resonance imaging (ZTE-MRI) had an accuracy of 81.8% and 93.7% for stones larger than 5 mm and 10 mm, respectively. ZTE-MRI is a potential non-irradiating method for the diagnosis and management of urolithiasis.

[Renal colic]

INTRODUCTION

Renal colic accounts for 5-10% of all emergency department visits, making it a common condition in acute medicine. The typical clinical presentation is an early indication of urolithiasis.

DIAGNOSIS

Diagnostic measures include laboratory tests, ultrasound, and low-dose noncontrast computed tomography (CT) scans. Kidney, ureter, bladder (KUB) plain film radiography has been widely replaced by low-dose noncontrast CT with similar radiation dosage. In special patient groups such as children or pregnant women, ionizing radiation should be avoided if possible.

TREATMENT

General measures involve pain management (non-steroidal anti-inflammatory agents, opioids) and empirical antibiotic treatment for suspected bacterial infection. Depending on the location/size of the stone, pharmacological stone expulsion therapy may be considered. In cases of obstructive pyelonephritis or acute renal insufficiency, early urinary drainage (JJ stent/nephrostomy) is recommended. Definitive stone removal may be performed primarily in some cases (rather small and rather distal ureterolithiasis). It is common to schedule stone removal as a secondary intervention.

ACR Appropriateness Criteria® Hydronephrosis on Prior Imaging-Unknown Cause

Initial imaging evaluation of hydronephrosis of unknown etiology is a complex subject and is dependent on clinical context. In asymptomatic patients, it is often best conducted via CT urography (CTU) without and with contrast, MR urography (MRU) without and with contrast, or scintigraphic evaluation with mercaptoacetyltriglycine (MAG3) imaging. For symptomatic patients, CTU without and with contrast, MRU without and with contrast, MAG3 scintigraphy, or ultrasound of the kidneys and bladder with Doppler imaging are all viable initial imaging studies. In asymptomatic pregnant patients, nonionizing imaging with US of the kidneys and bladder with Doppler imaging is preferred. Similarly, in symptomatic pregnant patients, US of the kidneys and bladder with Doppler imaging or MRU without contrast is the imaging study of choice, as both ionizing radiation and gadolinium contrast are avoided in pregnancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

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.

Image Enhancement Model Based on Deep Learning Applied to the Ureteroscopic Diagnosis of Ureteral Stones during Pregnancy

OBJECTIVE

To explore the image enhancement model based on deep learning on the effect of ureteroscopy with double J tube placement and drainage on ureteral stones during pregnancy. We compare the clinical effect of ureteroscopy with double J tube placement on pregnancy complicated with ureteral stones and use medical imaging to diagnose the patient's condition and design a treatment plan.

METHODS

The image enhancement model is constructed using deep learning and implemented for quality improvement in terms of image clarity. In the way, the relationship of the media transmittance and the image with blurring artifacts was established, and the model can estimate the ureteral stone predicted map of each region. Firstly, we proposed the evolution-based detail enhancement method. Then, the feature extraction network is used to capture blurring artifact-related features. Finally, the regression subnetwork is used to predict the media transmittance in the local area. Eighty pregnant patients with ureteral calculi treated in our hospital were selected as the research object and were divided into a test group and a control group according to the random number table method, 40 cases in each group. The test group underwent ureteroscopy double J tube placement, and the control group underwent ureteroscopy lithotripsy. Combined with the ultrasound scan results of the patients before and after the operation, the operation time, time to get out of bed, and hospitalization time of the two groups of patients were compared. The operation success rate and the incidence of complications within 1 month after surgery were counted in the two groups of patients.

RESULTS

We are able to improve the quality of the images prior to medical diagnosis. The total effective rate of the observation group was 100.0%, which is higher than that of the control group (90.0%). The difference between the two groups was statistically significant (P < 0.05). The adverse reaction rate in the observation group was 5.0%, which was lower than 17.5% in the control group. The difference between the two groups was statistically significant (P < 0.05). The comparison results are then prepared.

CONCLUSIONS

The image enhancement model based on deep learning is able to improve medical diagnosis which can assist radiologists to better locate the ureteral stones. Based on our method, double J tube placement under ureteroscopy has a significant effect on the treatment of ureteral stones during pregnancy, and it has good safety and is worthy of widespread application.

Management of ureteric stone in pregnancy: a review

Background

Urolithiasis in pregnancy is a major health concern and is one of the most common causes for non-obstetrical abdominal pain and subsequent hospital admission during pregnancy. The incidence of urinary calculi during pregnancy varies in the range of 1/200 to 1/2000. Acute ureteric colic in pregnancy is associated with significant potential risks to both mother and fetus. Significant anatomic and functional changes occur in pregnancy which not only lead to stone formation but also create diagnostic dilemma. The diagnosis of ureteric calculi can be incorrect in about 28% of pregnant patients.

Main body

Management of ureteric stone during pregnancy is remaining to be a challenge for the treating urologist. Because of the inability to use good imaging options for the diagnosis confirmation and more invasive approach for the treatment, management continues to be difficult. The main threats are preterm labor with delivery and premature rupture of membranes. Other pregnancy complications are obstructive uropathy, gestational diabetes mellitus, recurrent abortions and pre-eclampsia. Management of diagnosed ureteric stone is unique in the pregnant population and requires multi-disciplinary care. It should be individualized for each patient and moves preferably from conservative to invasive approaches sequentially. With continued advancements in endourological techniques, few definitive treatment options are also available for such patients.

Conclusion

There are several lacunae related with the diagnostic imaging, medical expulsive therapy, reliability of ureteral stent/percutaneous nephrostomy insertions and safety of ureteroscopy during pregnancy. Herein, we review the management of ureteric stone during pregnancy, the various diagnostic modalities and treatment options with their advantages and disadvantages. We also proposed our management algorithm to deal with such clinical scenario in this particular population.

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.

Imaging strategies for patients with suspicion of uncomplicated colic pain: diagnostic accuracy and management assessment

OBJECTIVE

Compare different imaging scenarios in the diagnosis of uncomplicated renal colic due to urolithiasis (URCU).

MATERIALS AND METHODS

A total of 206 prospectively included patients had been admitted with suspected URCU and had undergone abdominal plain film (APF), US and unenhanced CT after clinical STONE score evaluation. CT was the reference standard. We assessed sensitivity (Se), specificity (Spe) and Youden index for colic pain diagnosis, percentage of patients managed by urologic treatment with stone identified, percentage of alternative diagnoses (AD) and exposure to radiation, according to single imaging approaches, strategies driven by patient characteristics and conditional imaging strategies after APF and US.

RESULTS

One hundred (48.5%) patients had a final diagnosis of URCU and 19 underwent urologic treatment. The conditional strategy, i.e. CT in patients who had no stone identified at US, had a perfect sensitivity and specificity. This enabled diagnosis of all stones requiring urology management while decreasing the number of CT exams by 22%. The strategy whereby CT was used when there was neither direct or indirect APF + US finding of colic pain nor alternative diagnoses in patients with a STONE score ≥ 10 had a sensitivity of 0.95 and a specificity of 0.99, identified 84% of stones managed by urologic treatment and decreased the number of CT examinations by 76%.

CONCLUSION

In patients with clinical findings consistent with URCU, the use of ultrasound as first-line imaging modality, with CT restricted to patients with negative US and a STONE score ≥ 10, led to a sensitivity and specificity of above 95%, identified 84% of stones requiring urological management and reduced the number of CT scans needed by fourfold.

KEY POINTS

• For diagnosis, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, provides both a sensitivity and specificity superior or equal to 95% and reduces the number of CT scans necessary by fourfold. • For management, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, maintains a 84% stone identification rate in urology-treated patients.

Surgical Management of Urolithiasis of the Upper Tract - Current Trend of Endourology in Africa

Urolithiasis is a global pathology with increasing prevalence rate. The lifetime recurrence of urolithiasis ranges from 10–75% creating a public health crisis in affected regions. The epidemiology of urolithiasis in most parts of Africa and Asia remains poorly documented as incidence and prevalence rates in these settings are extrapolated from hospital admissions. The surgical management of kidney and ureteral stones is based on the stone location, size, the patient’s preference and the institutional capacity. To date, the available modalities in the management of urolithiasis includes external shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopy (URS) including flexible and semirigid ureteroscopy. However, regarding the lack of endourological equipment and expertise in most parts of Sub-Saharan Africa (SSA), most urological centers in these regions still consider open surgery for kidney and ureteral stones. This review explores the current trend and surgical management of upper tract urolithiasis in SSA with insight on the available clinical guidelines.

Contemporary best practice urolithiasis in pregnancy

Urolithiasis is the most common nonobstetric complication in the gravid patient. The experience can provoke undue stress for the mother, fetus, and management team. The physiologic changes of pregnancy render the physical exam and imaging studies less reliable than in the typical patient. Diagnosis is further complicated by the need for careful selection of imaging modality in order to maximize diagnostic utility and minimize obstetric risk to the mother and ionizing radiation exposure to the fetus. Ultrasound remains the first-line diagnostic imaging modality in this group, but other options are available if results are inconclusive. A trial of conservative management is uniformly recommended. In patients who fail spontaneous stone passage, treatment may be temporizing or definitive. While temporizing treatments have classically been deemed the gold standard, ureteroscopic stone removal is now acknowledged as a safe and highly effective definitive treatment approach. Ultimately, a multidisciplinary, team-based approach involving the patient, her obstetrician, urologist, radiologist, and anesthesiologist is needed to devise a maximally beneficial management plan.

Urolithiasis in pregnancy

Urolithiasis in pregnancy is a major health concern and can potentially affect the well-being of both mother and foetus. Management of this condition often entails simultaneous multidisciplinary involvement of obstetrician, radiologist and urologist. Additionally, adverse effects with usage of anaesthesia, radiation, medications and surgery on mother and foetus, limit utilisation of the full armamentarium of diagnostic and therapeutic modalities that are commonly used in non-pregnant women. This review was conducted using an electronic literature search of peer reviewed journal articles. Clinical studies were identified in the bibliographic database- PubMed (Medline), Ovid and eMedicine(WebMD) using the keywords: hydronephrosis, urolithiasis, kidney stone, urinary tract infection, pregnancy and ultrasound, incidence and epidemiology of renal stones.