[18F]F-Choline PET/CT and 4D-CT in the evaluation of primary hyperparathyroidism: rivals or allies?

Primary hyperparathyroidism is a hard-to-diagnose condition that can run without symptoms for many years without causing symptoms; yet, it can cause dire long-term consequences, such as osteoporosis and renal impairment. First-line diagnostic methods include ultrasound and parathyroid scintigraphy, which provide unsatisfactory results in terms of detection rate. Second-line imaging methods include [18F]F-Choline PET/CT, 4D-CT, and their combination. These methods have shown a great detection rate and sensitivity; however, they are to this day less widespread than the first-line ones. Both the two methods (PET and 4D-CT) have their specific advantages and field of application, as well as their specific limitations. In this narrative review, we will describe the advantages and disadvantages of the two techniques extensively. Moreover, we will try to identify whether the combined examination can play a role and how relevant this role is. Finally, we will try to define the specific clinical situation in which each method can provide the best contribution to diagnosing parathyroid tissue hyperfunction.

COVID-19 in a Patient with ß-Thalassemia Major and Severe Pulmonary Arterial Hypertension.

We here report the successful recovery from coronavirus disease-19 (COVID-19) pneumonia in a patient with ß-thalassemia major (ß-TM) and severe pulmonary arterial hypertension (PAH), focusing on the patient's comorbidities, therapeutic course and drug interaction.

Comparison between different software programs and post-processing techniques for the MRI quantification of liver iron concentration in thalassemia patients.

PURPOSE: In magnetic resonance imaging (MRI) relaxometry, various software programs are available to perform R2* measurements and to estimate the liver iron concentration (LIC). The main objective of our study was to compare R2* LIC values, obtained with three different software programs based on specific decay models and calibration curves, with LIC estimates provided by R2-relaxometry (FerriScan). METHODS: This retrospective study included 15 patients with 15 baseline MRIs and 34 serial examinations. R2* LIC estimates were calculated using the FuncTool, CMRtools/Thalassemia Tools and Quanta Hematology programs. Longitudinal LIC changes (ΔLIC) were calculated using the subset of 34 serial MRIs. RESULTS: After Bland-Altman analysis on baseline data, Quanta Hematology, which employs the monoexponential-plus-constant fit, produced the lowest mean difference [0.01 ± 0.14 log(mg/gdw)] with the closest limits of agreement. In the longitudinal setting, Quanta Hematology again gave the lowest mean difference between R2 and R2* LIC (0.1 ± 2.6 mg/gdw). Using FerriScan as reference, the value of concordant directional ΔLIC changes was the same for all programs (27/34, 85.7 %). CONCLUSIONS: R2* LICs are higher than R2 LICs at iron levels <7 mg/gdw, while R2 LIC averages higher than R2* LIC with increasing iron load. The monoexponential-plus-constant model provided the best agreement with R2 LIC estimates.

Characterization of ferromagnetic or conductive properties of metallic foreign objects embedded within the human body with magnetic iron detector (MID): Screening patients for MRI.

PURPOSE: A preliminary assessment of the MRI-compatibility of metallic object possibly embedded within the patient is required before conducting the MRI examination. The Magnetic Iron Detector (MID) is a highly sensitive susceptometer that uses a weak magnetic field to measure iron overload in the liver. MID might be used to perform a screening procedure for MRI by determining the ferromagnetic/conductive properties of embedded metallic objects. METHODS: The study was composed by: (i) definition of MID sensitivity threshold; (ii) application of MID in a procedure to characterize the ferromagnetic/conductive properties of metallic foreign objects in 958 patients scheduled for MID examination. RESULTS: The detection threshold for ferromagnetic objects was found to be the equivalent of a piece of wire of length 2 mm and gauge 0.8 mm(2) and, representing purely conductive objects, an aluminum sheet of area 2 × 2 cm(2) . Of 958 patients, 165 had foreign bodies of unknown nature. MID was able to detect those with ferromagnetic and/or conducting properties based on fluctuations in the magnetic and eddy current signals versus control. CONCLUSION: The high sensitivity of MID makes it suitable for assessing the ferromagnetic/conductive properties of metallic foreign objects embedded within the body of patients scheduled for MRI.

Value of bimodal (18)F-choline-PET/MRI and trimodal (18)F-choline-PET/MRI/TRUS for the assessment of prostate cancer recurrence after radiation therapy and radical prostatectomy.

Between 27% and 53% of all patients who undergo radical prostatectomy (RP) or radiation therapy (RT) as the first-line treatment of prostate cancer (PCa) develop a biochemical recurrence. Imaging plays a pivotal role in restaging by helping to distinguish between local relapse and metastatic disease (i.e., lymph-node and skeletal metastases). At present, the most promising tools for assessing PCa patients with biochemical recurrence are multiparametric magnetic resonance imaging (mpMRI) and positron emission tomography (PET)/computed tomography (CT) with radio-labeled choline derivatives. The main advantage of mpMRI is its high diagnostic accuracy in detecting local recurrence, while choline-PET/CT is able to identify lymph-node metastases when they are not suspicious on morphological imaging. The most recent advances in the field of fusion imaging have shown that multimodal co-registration, synchronized navigation, and combined interpretation are more valuable than the individual; separate assessment offered by different diagnostic techniques. The objective of the present essay was to describe the value of bimodal choline-PET/mpMRI fusion imaging and trimodal choline-PET/mpMRI/transrectal ultrasound (TRUS) in the assessment of PCa recurrence after RP and RT. Bimodal choline-PET/mpMRI fusion imaging allows morphological, functional, and metabolic information to be combined, thereby overcoming the limitations of each separate imaging modality. In addition, trimodal real-time choline-PET/mpMRI/TRUS fusion imaging may be useful for the planning and real-time guidance of biopsy procedures in order to obtain histological confirmation of the local recurrence.

Multimodality fusion imaging in abdominal and pelvic malignancies: current applications and future perspectives.

Medicine is evolving toward personalized care and this development entails the integration, amalgamation, and synchronized analysis of data from multiple sources. Multimodality fusion imaging refers to the simultaneous visualization of spatially aligned and juxtaposed medical images obtained by two or more image modalities. PET/MRI scanners and MMFI platforms are able to improve the diagnostic workflow in oncologic patients and provide exquisite images that aid physicians in the molecular profiling and characterization of tissues. Advanced navigation platforms involving real-time ultrasound are promising tools for guiding personalized and tailored mini-invasive interventional procedures on technically challenging targets. The main objective of the present essay was to describe the current applications and future perspectives of multimodality fusion imaging for both diagnostic and interventional purposes in the field of abdominal and pelvic malignancies. We also outlined the technical differences between fusion imaging achieved by means of simultaneous bimodal acquisition (i.e., integrated PET/MRI scanners), retrospective co-registration, and multimodality fusion imaging involving ultrafast or real-time imaging modalities.

Incidental physiological sliding hiatal hernia: a single center comparison study between CT with water enema and CT colonography.

PURPOSE: Hiatal hernia is a well-known factor impacting on most mechanisms underlying gastroesophageal reflux, related with the risk of developing complications such as erosive esophagitis, Barrett's esophagus and ultimately, esophageal adenocarcinoma. It is our firm opinion that an erroneous reporting of hiatal hernia in CT exams performed with colonic distention may trigger a consecutive diagnostic process that is not only unnecessary, inducing a unmotivated anxiety in the patient, but also expensive and time-consuming for both the patient and the healthcare system. The purposes of our study were to determine whether colonic distention at CT with water enema and CT colonography can induce small sliding hiatal hernias and to detect whether hiatal hernias size modifications could be considered significant for both water and gas distention techniques. METHODS: We retrospectively evaluated 400 consecutive patients, 200 undergoing CT-WE and 200 undergoing CTC, including 59 subjects who also underwent a routine abdominal CT evaluation on a different time, used as internal control, while a separate group of 200 consecutive patients who underwent abdominal CT evaluation was used as external control. Two abdominal radiologists assessed the CT exams for the presence of a sliding hiatal hernia, grading the size as small, moderate, or large; the internal control groups were directly compared with the corresponding CT-WE or CTC study looking for a change in hernia size. We used the Student's t test applying a size-specific correction factor, in order to account for the effect of colonic distention: these "corrected" values were then individually compared with the external control group. RESULTS: A sliding hiatal hernia was present in 51 % (102/200) of the CT-WE patients and in 48.5 % (97/200) of the CTC patients. Internal control CT of the 31 patients with a hernia at CT-WE showed resolution of the hernia in 58.1 % (18/31) of patients, including 76.5 % (13/17) and 45.5 % (5/11) of small and moderate hernias. Comparison CT of the 28 patients with a hiatal hernia at CTC showed the absence of the hernia in 57.1 % (16/28) patients, including 68.8 % (11/16) and 50 % (5/10) of small and moderate hernias. The prevalence of sliding hiatal hernias in the external control group was 22 % (44/200), significantly lower than the CT-WE and CTC cohorts' prevalence of 51 % (p < 0.0001) and 48.5 % (p < 0.0001). After applying the correction factors for the CT-WE and the CTC groups, the estimated residual prevalences (16 and 18.5 %, respectively) were much closer to that of the external control patients (p = 0.160 for CT-WE and p = 0.455 for CTC). CONCLUSIONS: We believe that incidental findings at CT-WE and CTC should be considered according to the clinical background, and that small sliding hiatal hernias should not be reported in patients with symptoms not related to reflux disease undergoing CT-WE or CTC: When encountering these findings, accurate anamnesis and review of medical history looking for GERD-related symptoms are essential, in order to address these patients to a correct diagnostic iter, taking advantage from more appropriate techniques such as endoscopy or functional techniques.

Advantages of percutaneous abdominal biopsy under PET-CT/ultrasound fusion imaging guidance: a pictorial essay.

Positron emission tomography (PET) is a functional imaging technique that can investigate the metabolic characteristics of tissues. Currently, PET images are acquired and co-registered with a computed tomography (CT) scan (PET-CT), which is employed for correction of attenuation and anatomical localization. In spite of the high negative predictive value of PET, false-positive results may occur; indeed, Fluorine 18 ((18)F)-fluorodeoxyglucose ((18)F-FDG) uptake is not specific to cancer. As (18)F-FDG uptake may also be seen in non-malignant infectious or inflammatory processes, FDG-avid lesions may necessitate biopsy to confirm or rule out malignancy. However, some PET-positive lesions may have little or no correlative ultrasound (US) and/or CT findings (i.e., low conspicuity on morphological imaging). Since it is not possible to perform biopsy under PET guidance alone, owing to intrinsic technical limitations, PET information has to be integrated into a CT- or US-guided biopsy procedure (multimodal US/PET-CT fusion imaging). The purpose of this pictorial essay is to describe the technique of multimodal imaging fusion between real-time US and PET/CT, and to provide an overview of the clinical settings in which this multimodal integration may be useful in guiding biopsy procedures in PET-positive abdominal lesions.

Safety of meglumine gadoterate (Gd-DOTA)-enhanced MRI compared to unenhanced MRI in patients with chronic kidney disease (RESCUE study).

OBJECTIVE: To prospectively compare the renal safety of meglumine gadoterate (Gd-DOTA)-enhanced magnetic resonance imaging (MRI) to a control group (unenhanced MRI) in high-risk patients. METHODS: Patients with chronic kidney disease (CKD) scheduled for MRI procedures were screened. The primary endpoint was the percentage of patients with an elevation of serum creatinine levels, measured 72 ± 24 h after the MRI procedure, by at least 25 % or 44.2 µmol/l (0.5 mg/dl) from baseline. A non-inferiority margin of the between-group difference was set at -15 % for statistical analysis of the primary endpoint. Main secondary endpoints were the variation in serum creatinine and eGFR values between baseline and 72 ± 24 h after MRI and the percentage of patients with a decrease in eGFR of at least 25 % from baseline. Patients were screened for signs of nephrogenic systemic fibrosis (NSF) at 3-month follow-up. RESULTS: Among the 114 evaluable patients, one (1.4 %) in the Gd-DOTA-MRI group and none in the control group met the criteria of the primary endpoint [Δ = -1.4 %, 95%CI = (-7.9 %; 6.7 %)]. Non-inferiority was therefore demonstrated (P = 0.001). No clinically significant differences were observed between groups for the secondary endpoints. No serious safety events (including NSF) were noted. CONCLUSION: Meglumine gadoterate did not affect renal function and was a safe contrast agent in patients with CKD. KEY POINTS: • Contrast-induced nephropathy (CIN) is a potential problem following gadolinium administration for MRI. • Meglumine gadoterate (Gd-DOTA) appears safe, even in patients with chronic kidney disease. • Gd-DOTA only caused a temporary creatinine level increase in 1/70 such patients. • No case or sign of NSF was detected at 3-month follow-up.

Effect of Aging on Deferasirox Therapy in Transfusion-dependent Patients. A prospective-retrospective, cohort-study.

BACKGROUND: Iron-chelation therapy is life-saving in patients on a chronic transfusion regimen as it reduces organ damage related to iron deposition in the tissues. Deferasirox, an iron-chelator, is characterized by pharmacokinetics variability, and some patients may discontinue the treatment due to toxicities. OBJECTIVE: Understanding whether deferasirox plasma levels are related to patients' specific characteristics could help optimize DFX dosage. METHODS: We analyzed deferasirox plasma concentration in 57 transfusion-dependent anemic patients using the HPLC method in this prospective-retrospective cohort study. All outpatients (3 to 98 years) were treated with deferasirox (film-coated tablet) for at least one year (median dose, 16.5 mg/Kg once a day). Deferasirox plasma concentration was normalized for dose/Kg (C/dose) and corrected with a linear regression model that relates C/dose and the time of blood sampling (Cref/dose). RESULTS: No significant differences in Cref/dose were found between males and females, either between different types of hemoglobinopathies or depending on the presence of the UGT1A1*28 polymorphism. Cref/dose has a positive and significant correlation with age, creatinine, and direct bilirubin. Cref/dose, instead, has a negative and significant correlation with Liver Iron Concentration (LIC), ferritin, and eGFR. Cref/dose was significantly different between three age categories <18yrs, 18-50yrs, and >50yrs, with Cref/dose median values of 1.0, 1.2, and 1.5, respectively. CONCLUSION: The study evidenced that to ensure the efficacy of deferasirox in terms of control over LIC and, at the same time, a lesser influence on renal function, the dose of the drug to be administered to an elderly patient could be reduced.

Musculoskeletal manifestations of chronic anemias.

This article provides an overview of the current use of diagnostic imaging modalities in the evaluation of a heterogeneous group of disorders causing chronic anemias by impaired blood cell production (inherited bone marrow failure syndromes of childhood, aplastic anemia and myelodysplastic syndromes, ß-thalassemia) or increased blood cell destruction (sickle cell disease). During the course of these disorders, various musculoskeletal abnormalities can be encountered, including marrow hyperplasia, reversion of yellow marrow to red marrow, growth disturbances, and, occasionally, extramedullary hematopoiesis. Diagnostic imaging may help the clinician to identify specific complications related to either the disease (e.g., bone infarction and acute osteomyelitis in sickle cell disease) or transfusion (e.g., iron overload due to increased hemolysis) and iron chelation (e.g., desferrioxamine-related dysplastic bone changes and deferiprone-related degenerative arthritis) treatments. In this field, magnetic resonance imaging plays a pivotal role because of its high tissue contrast that enables early assessment of bone marrow changes before they become apparent on plain films or computed tomography or metabolic changes occur on bone scintigraphy or positron emission tomography scan. Overall, familiarity with the range of radiological appearances in chronic anemias is important to diagnose complications and establish appropriate therapy.

Will 18F-fluorocholine PET/CT replace other methods of preoperative parathyroid imaging?

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disorder usually due to hyperfunctioning parathyroid glands (HPs). Surgical removal of the HPs is the main treatment for PHPT, making the correct detection and localization of HPs crucial to guiding targeted and minimally invasive surgical treatment in patients with PHPT. To date, different imaging methods have been used to detect and localize HPs, including radiology, nuclear medicine, and hybrid techniques. METHODS: The present work discusses the role and value of different imaging methods in PHPT and, particularly, evaluates the potential role of 18F-fluorcholine PET/CT as a "one-stop-shop" method for preoperative parathyroid localization in patients with PHPT. DISCUSSION: Cervical ultrasound (US) and parathyroid scintigraphy using 99mTc-MIBI are the most commonly employed methods in clinical practice. More recently, four-dimensional computed tomography (4D CT) and positron emission tomography (PET) with radiolabeled choline have emerged as useful alternatives in cases of negative or discordant findings from first-line imaging methods. CONCLUSIONS: Due to the excellent diagnostic performance of radiolabeled choline PET/CT and the low radiation burden, this technique seems to be an ideal candidate to substitute current imaging procedures including US, MIBI scintigraphy, 4D CT and MRI and perform a fast and reliable "one-stop-shop" preoperative localization of HP in patients with PHPT, including challenging cases of postoperative persistent/recurrent disease.

Head-to-head comparison among 18F-choline PET/CT, 4D contrast-enhanced CT, and 18F-choline PET/4D contrast-enhanced CT in the detection of hyperfunctioning parathyroid glands: a systematic review and meta-analysis.

INTRODUCTION: In primary hyperparathyroidism (PHPT), the localization of hyperfunctioning parathyroid gland (HPTG) allows tailored surgery. Although Four-Dimensional Contrast-enhanced Computed Tomography (4DCeCT) and 18F-choline Positron Emission Tomography/Computed Tomography (PET/CT) are reported to be promising second-line imaging procedures, no meta-analysis of their comparison exists. DESIGN: we conducted a systematic review and meta-analysis to find original papers reporting the head-to-head comparison of 4DCeCT, 18F-choline PET/CT and integrated 18F-choline-PET/4DCeCT. METHODS: this systematic review was conducted according to PRISMA. PubMed, CENTRAL, Scopus, and Web of Science were searched until January 2021. Studies comparing the ability of 4DCeCT, 18F-choline PET/CT and 18F-choline PET/4DCeCT to identify HPTG in patients with PHPT were selected. A per patient-based analysis of the three procedures was conducted in all patients (detection rate, DR) and in those with histologically confirmed HPTG (sensitivity). RESULTS: Of the 78 records identified, five articles (153 PHPT patients) published between January the 1st, 2018 and January the 31st, 2021 were included. The pooled DR of 18F-choline PET/CT, 4DCeCT and 18F-choline PET/4DCeCT was 0.86, 0.69, and 0.86, respectively, while their pooled sensitivity was 0.89, 0.77 and 0.93, respectively. The analysis of pooled discrepancy showed that the sensitivity of 18F-choline PET/CT and 18F-choline PET/4DCeCT was higher than that of 4DCeCT by 0.11 and 0.13, respectively, the sensitivity of 18F-choline PET/4DCeCT being 0.06 higher than that of 18F-Choline PET/CT. CONCLUSIONS: This meta-analysis suggests that the sensitivity of 18F-choline PET/CT and 18F-choline PET/4DCeCT is higher than that of 4DCeCT, while only a slight difference was observed between 18F-choline PET/CT and 18F-choline PET/4DCeCT.

Evaluation of novel coronavirus disease (COVID-19) using quantitative lung CT and clinical data: prediction of short-term outcome.

BACKGROUND: Computed tomography (CT) enables quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, helping in outcome prediction. METHODS: From 1 to 22 March 2020, patients with pneumonia symptoms, positive lung CT scan, and confirmed SARS-CoV-2 on reverse transcription-polymerase chain reaction (RT-PCR) were consecutively enrolled. Clinical data was collected. Outcome was defined as favourable or adverse (i.e., need for mechanical ventilation or death) and registered over a period of 10 days following CT. Volume of disease (VoD) on CT was calculated semi-automatically. Multiple linear regression was used to predict VoD by clinical/laboratory data. To predict outcome, important features were selected using a priori analysis and subsequently used to train 4 different models. RESULTS: A total of 106 consecutive patients were enrolled (median age 63.5 years, range 26-95 years; 41/106 women, 38.7%). Median duration of symptoms and C-reactive protein (CRP) was 5 days (range 1-30) and 4.94 mg/L (range 0.1-28.3), respectively. Median VoD was 249.5 cm3 (range 9.9-1505) and was predicted by lymphocyte percentage (p = 0.008) and CRP (p < 0.001). Important variables for outcome prediction included CRP (area under the curve [AUC] 0.77), VoD (AUC 0.75), age (AUC 0.72), lymphocyte percentage (AUC 0.70), coronary calcification (AUC 0.68), and presence of comorbidities (AUC 0.66). Support vector machine had the best performance in outcome prediction, yielding an AUC of 0.92. CONCLUSIONS: Measuring the VoD using a simple CT post-processing tool estimates SARS-CoV-2 burden. CT and clinical data together enable accurate prediction of short-term clinical outcome.

Diagnostic value of retrospectively fused 64CuCl2 PET/MRI in biochemical relapse of prostate cancer: comparison with fused 18F-Choline PET/MRI, 64CuCl2 PET/CT, 18F-Choline PET/CT, and mpMRI.

PURPOSE: To assess the diagnostic value of retrospectively fused PET/MRI by comparing the detection rates (DRs) of fused 64CuCl2 PET/MRI vs. fused 18F-Choline PET/MRI in patients with suspected prostatic cancer (PCa) recurrence. The secondary objective was to compare the DRs of fused PET/MRI vs. those of the separate imaging modalities. METHODS: We retrospectively evaluated 50 PCa patients with biochemical relapse after radical prostatectomy (RP) or radiotherapy (RT). All patients underwent 64CuCl2 PET/CT, 18F-Choline PET/CT, and multiparametric magnetic resonance imaging (mpMRI) within 15 days. Fused 64CuCl2-PET/MRI and fused 18F-Choline PET/MRI images were obtained by retrospective co-registration of MRI and PET images. Experienced readers interpreted the images, and the DRs of each imaging modality were assessed. RESULTS: In the patient-based analysis, overall DRs of fused 64CuCl2 PET/MRI, fused 18F-Choline PET/MRI, 64CuCl2 PET/CT, 18F-Choline PET/CT, and mpMRI were 88%, 68%, 82%, 56%, and 74%, respectively. In the lesion-based analysis, overall DRs of fused 64CuCl2 PET/MRI, fused 18F-Choline PET/MRI, 64CuCl2 PET/CT, 18 F-Choline PET/CT, and mpMRI were 95%, 66%, 87%, 58%, and 71%, respectively. CONCLUSIONS: Retrospectively fused PET/MRI is able to overcome the limitations of the separate interpretation of the individual imaging modalities. Fused 64CuCl2 PET/MRI provided the highest diagnostic performance in the detection of PCa local relapse.

Computed tomography colonography in acromegaly.

INTRODUCTION AND AIM: Acromegalic patients have an increased risk for the development of colorectal cancer. For this reason, since 1996, screening colonoscopy has been recommended in all patients with acromegaly. The aim of our study was to assess the feasibility and to evaluate the results of computed tomography (CT)-colonography in acromegaly. PATIENTS AND METHODS: We examined 23 acromegalic patients with no history of colorectal cancer (11 females and 12 males; age range 18-79 yr; disease duration range 1-15 yr) with CT-colonography. Twenty of them underwent traditional colonoscopy after the CT-colonography. RESULTS: CT-colonography examination results were adequate in 17 of 23 cases (73%). CT-colonography found 12 polyps in eight patients, 95% confirmed by traditional colonoscopy. One polyp was a sigmoid cancer, and the diagnosis was confirmed at surgery. There were no polyps found by traditional colonoscopy that CT-colonography was not able to identify. The lesions were located in right colon (two), transversum (three), left colon (five), and sigmoid colon (two). Patient acceptance of the technique was good in 65%, medium in 20%, and poor in 15%. CONCLUSION: For the first time we have demonstrated that CT-colonography has the potential ability to replace traditional colonoscopy in acromegalic patients. CT-colonography could be used as a screening modality for colon cancer in acromegaly.

[Flexible cystoscope for the treatment of urinary stones in intestinal reservoirs.] / Cistoscopia flexible para el tratamiento de las litiasis urinarias en reservorios intestinales.

OBJECTIVE: Stones are common mid- and long-term complications in urinary diversions built with bowel. However the reservoir intestinal loops can lead to difficult endoscopic approach. METHODS: We report two challenging cases with unfavourable anatomy successfully treated by gently handling a flexible cystoscope in a low pressure system. RESULTS: One patient with stones in a continent pouch was cleaned up with a grasping basket through the efferent umbilical limb. Another patient with an orthotopic ileal neobladder not accessible by rigid cystoscope due to high pelvic floor was treated with holmiun laser lithotripsy. CONCLUSIONS: Urologists should consider the versatility of flexible cystoscope to obviate the need for percutaneous lithotripsy or open lithotomy.

OBJETIVO: La aparición de litiasis es una complicación común a medio y largo plazo en las derivaciones urinarias construidas con intestino. Sin embargo, las asas intestinales de los reservorios pueden tener un acceso endoscópico difícil. METODOS: Presentamos dos casos difíciles con anatomía desfavorable tratados con éxito utilizando cuidadosamente un cistoscopio flexible en un sistema de baja presión. RESULTADOS: Un paciente con litiasis en una neovejiga continente quedó libre de litiasis utilizando una cestilla a través del asa eferente umbilical. Otro paciente con una neovejiga ileal ortotópica no accesible por cistoscopio rígido debido a un suelo pélvico elevado, fue tratado con litotricia con láser de Holmio. CONCLUSIONES: Los urólogos deben considerar la versatilidad de la cistoscopia flexible para obviar la necesidad de litotricia percutánea o litotomía abierta.