Multi-modality organ-based approach to expected imaging findings, complications and recurrent tumour in the genitourinary tract after radiotherapy

Imaging the post-treatment pelvis with gynecologic cancers

Gynecological malignancies, such as ovarian cancers, cervical cancers, and endometrial cancers, have a significant global impact. Women with gynecologic malignancies may receive a single or a combination of treatments, including surgery, chemotherapy, and radiation-based therapies. Radiologists utilize various diagnostic imaging modalities to provide the surgeon with relevant information about the diagnosis, prognosis, optimal surgical strategy, and prospective post-treatment imaging. Computerized Tomography (CT) and magnetic resonance imaging (MRI) may be used initially to evaluate and detect post-treatment complications. Although CT is primarily used for staging, MRI is commonly used for a more accurate evaluation of a tumor's size and detection of local invasion. Complications such as hematoma, abscess, inclusion cyst, seroma, tumor thrombosis, anorectovaginal fistula, and gossypiboma may occur after the three primary treatments, and systems such as the genitourinary, gastrointestinal, neurological, and musculoskeletal may be affected. In order to distinguish between early-onset and late-onset complications following gynecological treatment, radiological findings of the most common post-treatment complications will be presented in this review.

The Utility of Contrast-Enhanced Magnetic Resonance Imaging in Uterine Cervical Cancer: A Systematic Review

Correct staging of cervical cancer is essential to establish the best therapeutic procedure and prognosis for the patient. MRI is the best imaging modality for local staging and follow-up. According to the latest ESUR guidelines, T2WI and DWI-MR sequences are fundamental in these settings, and CE-MRI remains optional. This systematic review, according to the PRISMA 2020 checklist, aims to give an overview of the literature regarding the use of contrast in MRI in cervical cancer and provide more specific indications of when it may be helpful. Systematic searches on PubMed and Web Of Science (WOS) were performed, and 97 papers were included; 1 paper was added considering the references of included articles. From our literature review, it emerged that many papers about the use of contrast in cervical cancer are dated, especially about staging and detection of tumor recurrence. We did not find strong evidence suggesting that CE-MRI is helpful in any clinical setting for cervical cancer staging and detection of tumor recurrence. There is growing evidence that perfusion parameters and perfusion-derived radiomics models might have a role as prognostic and predictive biomarkers, but the lack of standardization and validation limits their use in a research setting.

Imaging of acute pelvic pain

Acute pelvic pain (APP) requires urgent medical evaluation and treatment. Differential diagnosis of APP is broad, including a variety of gynecologic and non-gynecologic/ urinary, gastrointestinal, vascular and other entities. Close anatomical and physiological relations of pelvic structures, together with similar clinical presentation of different disorders and overlapping of symptoms, especially in the emergency background, make the proper diagnosis of APP challenging. Imaging plays a crucial role in the fast and precise diagnosis of APP. Ultrasonography is the first-line imaging modality, often accompanied by CT, while MRI is utilized in specific cases, using short, tailored protocols. Recognizing the cause of APP in females is a challenging task, due to the wide spectrum of possible origin and overlap of their imaging features. Therefore, the radiologist has to be familiar with the possible causes of APP, and, relying on clinical presentation, together with laboratory findings, choose the best imaging strategy in order to establish a fast and accurate diagnosis.

Imaging side effects and complications of chemotherapy and radiation therapy: a pictorial review from head to toe

Newer biologic drugs and immunomodulatory agents, as well as more tolerated and effective radiation therapy schemes, have reduced treatment toxicity in oncology patients. However, although imaging assessment of tumor response is adapting to atypical responses like tumor flare, expected changes and complications of chemo/radiotherapy are still routinely encountered in post-treatment imaging examinations. Radiologists must be aware of old and newer therapeutic options and related side effects or complications to avoid a misinterpretation of imaging findings. Further, advancements in oncology research have increased life expectancy of patients as well as the frequency of long-term therapy-related side effects that once could not be observed. This pictorial will help radiologists tasked to detect therapy-related complications and to differentiate expected changes of normal tissues from tumor relapse.

Cervical cancer recurrence - can we predict the type of recurrence?

PURPOSE

We aimed to identify if there is an association between the severity of cervical cancer at diagnosis and the pattern of recurrence.

METHODS

We conducted a retrospective study of recurrent cervical cancers diagnosed between 2016 and 2018. We characterized the cases according to histology, size, FIGO stage (according to 2009 and 2018 FIGO classifications) and nodal involvement at diagnosis, symptoms at the time of recurrence, interval between the end of treatment and recurrence, imaging methods used, and location of the recurrence. Statistical analysis was performed between histology, size, FIGO stage and nodal involvement at diagnosis and time to recurrence and type of recurrence (locoregional versus lymph node, distant or multiple site involvement).

RESULTS

We included 48 patients with recurrent cervical cancer. At diagnosis, mean tumor size was 5 cm and 83% of the patients had squamous cell carcinoma. The FIGO stage changed in 43.8% of patients between the 2009 and the 2018 classifications. A mean of 26 months elapsed between the end of treatment and recurrence. Recurrence was symptomatic in 64.6% of patients. Imaging identified recurrence in 97.9% of patients. The most frequent recurrence sites were locoregional and lymph node metastases. We found a statistically significant association between 2009 FIGO stage and time to recurrence (P = 0.030) and lymph node involvement at diagnosis and type of recurrence (P = 0.022). As expected patients with more advanced disease recurred sooner, though this was only observed for the 2009 FIGO classification. Absence of lymph nodes at initial diagnosis was associated with locoregional recurrence, while presence of lymph node involvement was associated with lymph node, distant or multiple site involvement of recurrence. No other significant associations were found.

CONCLUSION

In our cohort of recurrent cervical cancer, we found an association between patients without lymph node metastases at initial diagnosis and locoregional recurrence. Further studies are needed in order to evaluate whether this association has predictive value.

MDCT Imaging of Acute Bladder Pathology

In this review, we will discuss and illustrate the pathophysiology, presentation, and multidetector computed tomography findings associated with emergent bladder conditions, limiting our discussion to traumatic, infectious, and obstructive etiologies. After reviewing computed tomography cystographic technique, the commonly utilized classification systems for bladder trauma will be presented with illustrative examples of associated typical and more infrequent secondary injuries and complications. Next, the pathogenesis and imaging appearance of both mechanical and neurogenic acute urinary retention will be addressed, including less common though potentially pathognomonic obstructive etiologies including urethral calculi and ectopic ureteroceles. Finally, we will review and illustrate the imaging features of both inflammatory and infectious cystitis, including hemorrhagic and emphysematous variants, as well as the potentially encountered secondary complications.

Deeply-learnt damped least-squares (DL-DLS) method for inverse kinematics of snake-like robots

Recently, snake-like robots are proposed to assist experts during medical procedures on internal organs via natural orifices. Despite their well-spelt advantages, applications in radiosurgery is still hindered by absence of suitable designs required for spatial navigations within clustered and confined parts of human body, and inexistence of precise and fast inverse kinematics (IK) models. In this study, a deeply-learnt damped least squares method is proposed for solving IK of spatial snake-like robot. The robot's model consists of several modules, and each module has a pair of serial-links connected with orthogonal twists. For precise control of the robot's end-effector, damped least-squares approach is used to minimize error magnitude in a function modeled over analytical Jacobian of the robot. This is iteratively done until an apt joint vector needed to converge the robot to desired positions is obtained. For fast control and singularity avoidance, a deep network is built for prediction of unique damping factor required for each target point in the robot's workspace. The deep network consists of 11 x 15 array of neurons at the hidden layer, and deeply-learnt with a huge dataset of 877,500 data points generated from workspace of the snake robot. Implementation results for both simulated and actual prototype of an eight-link model of the robot show the effectiveness of the proposed IK method. With error tolerance of 0.01 mm, the proposed method has a very high reachability measure of 91.59% and faster mean execution time of 9.20 (±16.92) ms for convergence. In addition, the method requires an average of 33.02 (±39.60) iterations to solve the IK problem. Hence, approximately 3.6 iterations can be executed in 1 ms. Evaluation against popularly used IK methods shows that the proposed method has very good performance in terms of accuracy and speed, simultaneously.

Added value of diffusion-weighted MRI in detection of cervical cancer recurrence: comparison with morphologic and dynamic contrast-enhanced MRI sequences

PURPOSE

We aimed to evaluate the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) for detecting post-treatment cervical cancer recurrence. The detection accuracy of T2-weighted (T2W) images was compared with that of T2W MRI combined with either dynamic contrast-enhanced (DCE) MRI or DWI.

METHODS

Thirty-eight women with clinically suspected uterine cervical cancer recurrence more than six months after treatment completion were examined with 1.5 Tesla MRI including T2W, DCE, and DWI sequences. Disease was confirmed histologically and correlated with MRI findings. The diagnostic performance of T2W imaging and its combination with either DCE or DWI were analyzed. Sensitivity, positive predictive value, and accuracy were calculated.

RESULTS

Thirty-six women had histologically proven recurrence. The accuracy for recurrence detection was 80% with T2W/DCE MRI and 92.1% with T2W/DWI. The addition of DCE sequences did not significantly improve the diagnostic ability of T2W imaging, and this sequence combination misclassified two patients as falsely positive and seven as falsely negative. The T2W/DWI combination revealed a positive predictive value of 100% and only three false negatives.

CONCLUSION

The addition of DWI to T2W sequences considerably improved the diagnostic ability of MRI. Our results support the inclusion of DWI in the initial MRI protocol for the detection of cervical cancer recurrence, leaving DCE sequences as an option for uncertain cases.

Cross-sectional imaging of complicated urinary infections affecting the lower tract and male genital organs

Complicated urinary tract infections (C-UTIs) are those associated with structural or functional genitourinary abnormalities or with conditions that impair the host defence mechanisms, leading to an increased risk of acquiring infection or failing therapy. C-UTIs occur in patients with risk factors such as neurogenic dysfunction, bladder outlet obstruction, obstructive uropathy, bladder catheterisation, urologic instrumentation or indwelling stent, urinary tract post-surgical modifications, chemotherapy- or radiation-induced damage, renal impairment, diabetes and immunodeficiency.

Multidetector CT and MRI allow comprehensive investigation of C-UTIs and systemic infection from an unknown source. Based upon personal experience at a tertiary care hospital focused on the treatment of infectious illnesses, this pictorial essay reviews with examples the clinical features and cross-sectional imaging findings of C-UTIs affecting the lower urinary tract and male genital organs. The disorders presented include acute infectious cystitis, bladder mural abscesses, infections of the prostate and seminal vesicles, acute urethritis and related perineal abscesses, funiculitis, epididymo-orchitis and scrotal abscesses. Emphasis is placed on the possible differential diagnoses of lower C-UTIs.

The aim is to provide radiologists greater familiarity with these potentially severe disorders which frequently require intensive in-hospital antibiotic therapy, percutaneous drainage or surgery.

Teaching Points

• Complicated urinary tract infections occur in patients with structural or functional risk factors.

• CT and MRI comprehensively investigate complicated urinary infections and sepsis from unknown sources.

• Infections of the urinary bladder, prostate, seminal vesicles, urethra and scrotum are presented.

• Emphasis is placed on differential diagnoses of complicated lower urogenital infections.

• Unsuspected urinary infections may be detected on CT performed for other clinical reasons.

Pictorial review. Magnetic resonance for radiotherapy management and treatment planning in prostatic carcinoma

MRI has an important role for radiotherapy (RT) treatment planning in prostate cancer (PCa) providing accurate visualization of the dominant intraprostatic lesion (DIL) and locoregional anatomy, assessment of local staging and depiction of implanted devices. MRI enables the radiation oncologist to optimize RT planning by better defining target tumour volumes (thereby increasing local tumour control), as well as decreasing morbidity (by minimizing the dose to adjacent normal structures). Using MRI, radiation oncologists can define the DIL for delivery of boost doses of RT using a variety of techniques including: stereotactic body radiotherapy, intensity-modulated radiotherapy, proton RT or brachytherapy to improve tumour control. Radiologists require a familiarity with the different RT methods used to treat PCa, as well as an understanding of the advantages and disadvantages of the various MR pulse sequences available for RT planning in order to provide an optimal multidisciplinary RT treatment approach to PCa. Understanding the expected post-RT appearance of the prostate and typical characteristics of local tumour recurrence is also important because MRI is rapidly becoming an integral component for diagnosis, image-guided histological sampling and treatment planning in the setting of biochemical failure after RT or surgery.