Diffusely Infiltrative Small Bowel Disease.

Multiple infiltrative disorders can affect the small bowel, often resulting in diffuse small bowel wall thickening. These infiltrative disorders can manifest owing to various factors such as an influx of immunologic or neoplastic cells or the accumulation of substances within one or more layers of the intestinal wall. Although there can be considerable overlap in the appearances of infiltrative diseases on cross-sectional images, a comprehensive understanding of more specific ancillary imaging features and clinicopathologic correlation can substantially narrow the differential diagnosis. The radiologist can be instrumental in synthesizing the clinical and imaging information and guiding subsequent workup. The authors present a comprehensive review of the infiltrative disorders that commonly involve the small bowel. These disorders are organized on the basis of their pathophysiologic features, with multiple illustrative case examples to enhance understanding of these entities. CT and MRI are currently the most commonly used imaging modalities for evaluating small bowel disorders, and this review is focused on these two modalities. Detailed information regarding the pathologic features, clinical presentation, and imaging findings of these infiltrative disorders is provided to aid radiologists in recognizing and differentiating these conditions. ©RSNA, 2024.

Endometriosis MR mimickers: T2-hypointense lesions.

Endometriosis is a common crippling disease in women of reproductive age. Magnetic resonance imaging (MRI) is considered the cornerstone radiological technique for both the diagnosis and management of endometriosis. While its sensitivity, especially in deep infiltrating endometriosis, is superior to that of ultrasonography, many sources of false-positive results exist, leading to a lack of specificity. Hypointense lesions or pseudo-lesions on T2-weighted images include anatomical variants, fibrous connective tissues, benign and malignant tumors, feces, surgical materials, and post treatment scars which may mimic deep pelvic infiltrating endometriosis. False positives can have a major impact on patient management, from diagnosis to medical or surgical treatment. This educational review aims to help the radiologist acknowledge MRI criteria, pitfalls, and the differential diagnosis of deep pelvic infiltrating endometriosis to reduce false-positive results. Critical relevance statement MRI in deep infiltrating endometriosis has a 23% false-positive rate, leading to misdiagnosis. T2-hypointense lesions primarily result from anatomical variations, fibrous connective tissue, benign and malignant tumors, feces, surgical material, and post-treatment scars. Key points • MRI in DIE has a 23% false-positive rate, leading to potential misdiagnosis.• Anatomical variations, fibrous connective tissues, neoplasms, and surgical alterations are the main sources of T2-hypointense mimickers.• Multisequence interpretation, morphologic assessment, and precise anatomic localization are crucial to prevent overdiagnosis.• Gadolinium injection is beneficial for assessing endometriosis differential diagnosis only in specific conditions.

MRI Features of Pelvic Nerve Involvement in Endometriosis.

Endometriosis is a common condition that mostly affects people assigned as female at birth. The most common clinical symptom of endometriosis is pain. Although the mechanism for this pain is poorly understood, in some cases, the nerves are directly involved in endometriosis. Endometriosis is a multifocal disease, and the pelvis is the most common location involved. Nerves in the pelvis can become entrapped and involved in endometriosis. Pelvic nerves are visible at pelvic MRI, especially when imaging planes and sequences are tailored for neural evaluation. In particular, high-spatial-resolution anatomic imaging including three-dimensional isotropic imaging and contrast-enhanced three-dimensional short inversion time inversion-recovery (STIR) fast spin-echo sequences are useful for nerve imaging. The most commonly involved nerves are the sciatic, obturator, femoral, pudendal, and inferior hypogastric nerves and the inferior hypogastric and lumbosacral plexuses. Although it is thought to be rare, the true incidence of nerve involvement in endometriosis is not known. Symptoms of neural involvement include pain, weakness, numbness, incontinence, and paraplegia and may be constant or cyclic (catamenial). Early diagnosis of neural involvement in endometriosis is important to prevent irreversible nerve damage and chronic sensorimotor neuropathy. Evidence of irreversible damage can also be seen at MRI, and radiologists should evaluate pelvic nerves that are commonly involved in endometriosis in their search pattern and report template to ensure that this information is incorporated into treatment planning.

Surgical Management of Endometriosis Involving the Bladder and Ureter.

BACKGROUND: Endometriosis is a chronic, debilitating condition affecting up to 10% of reproductive-age women. Urinary tract endometriosis is found in 1%-6% of women diagnosed with pelvic endometriosis, with the most common sites being the bladder (70%-85%), ureter (9%-23%), and kidney (4%). Patients typically present with symptoms such as lower abdominal pain, dysuria, and urgency. Unfortunately, urinary tract endometriosis is often asymptomatic, potentially leading to silent obstructive uropathy and kidney failure. OBJECTIVE: To demonstrate a step-by-step approach for the surgical management of urinary tract endometriosis using conventional laparoscopy for partial cystectomy and robotic-assisted laparoscopy for ureteroneocystostomy. MATERIAL AND METHOD: Surgical video of 2 cases managed in an academic tertiary referral center for endometriosis. The first case was a 38-year-old Gravida 3, Para 3 with a history of hysterectomy who had an MRI which revealed a T2 hypointense bladder nodule consistent with endometriosis. Patient had significant urinary urgency, dysuria, and suprapubpic pain that improved but did not disappear after starting oral progestin therapy (5 mg of norethindrone). A cystoscopy was first performed to confirm MRI findings of bladder lesion and to delineate borders and depth of invasion. The second case was a 35-year-old nulliparous woman with chronic pelvic pain and primary infertility. The patient had a history of stage IV endometriosis with deep endometriosis into the bowel and extrinsic encasement of the ureters causing subsequent hydronephrosis requiring bilateral ureteral stents. She had continued daily pelvic pain despite of being on oral contraceptives for medical management of endometriosis. She subsequently underwent bilateral percutaneous nephrostomy tube placement to allow for ureteral rest prior to surgery. RESULTS: In the first case, conventional laparoscopy was utilized to perform bilateral ureterolysis, bladder mobilization, partial cystectomy for complete excision of the lesion, and 2-layered bladder closure. Use of indigo carmine assisted with ureteral orifice identification. In the second case, a cystoscopy was performed with injection of Indocyanine green to assist with ureteral identification. After ureterolysis, distal ureteric obstruction due to extensive disease was confirmed on laparoscopy and ureteroscopy. Bilateral ureteroneocystostomy with placement of Double-J ureteral stents was performed using a robotic-assisted approach. Each patient had an indwelling Foley catheter for bladder decompression during recovery. Pathology in both cases revealed endometriosis. Both patients had an uneventful postoperative course. A postoperative retrograde cystogram confirmed adequate repair prior to removal of each Foley catheter. Patient 2 had uncomplicated office stent removal 6 weeks postoperatively and had a normal renal ultrasound with no hydronephrosis 6 months postoperatively. CONCLUSION: Endometriosis is an increasingly common condition. It is important for gynecological surgeons to have the proper understanding of anatomy, surgical technique, and multidisciplinary care needed with urology for safe and complete excision of bladder and ureter endometriosis.

Excision of Deep Endometriosis of the Rectosigmoid: Individualizing Care to the Presenting Pathology.

STUDY OBJECTIVE: To highlight different surgical approaches for managing deep infiltrating endometriosis involving the rectosigmoid colon. DESIGN: Demonstration of specific surgical techniques with educational narrated video footage. SETTING: Bowel endometriosis is reported in 3.8% to 37% of patients with endometriosis [1]. Most commonly, the rectosigmoid colon is involved. Pelvic ultrasound and magnetic resonance imaging may be useful in diagnosis and for surgical planning [2]. Treatment options include observation, medications, or surgery. There are various surgical techniques that can be used for excision of deep infiltrating endometriosis involving the rectosigmoid colon. Serosal shaving, discoid resection, and complete resection are the possible types of surgical interventions that are demonstrated in this surgical education video at an academic medical center. Serosal shaving is used for lesions with minimal involvement of the muscularis. It can be done sharply or with electrosurgery and it is imperative to assess bowel integrity after shaving. Discoid resection is used for lesions with muscularis involvement, <3 cm in size, and encompassing less than one-third to a half of the bowel circumference. Full-thickness discoid bowel resection can be done in various ways including manual resection with primary suture closure, regular stapler transabdominally, or EEA stapler (Medtronic EEA Circular Stapler, Minneapolis, MN) transrectally. Segmental resection is used for lesions >3 cm in size, involving >50% of the bowel circumference, or for multifocal lesions. Various suture and stapler methods exist for this technique. INTERVENTIONS: Based on the imaging and intraoperative findings, a surgical technique was chosen and demonstrated. The types of surgical techniques demonstrated include laparoscopic serosal shaving, discoid resection with manual resection and primary suture closure, discoid resection with EEA stapler, and segmental resection. CONCLUSION: Knowledge of different surgical approaches to excise endometriosis is essential to appropriately address a patient's unique pathology. The choice of which surgical technique to use should include consideration of the location of the lesion, depth and circumference of involvement, and the number of nodules present.

Feasibility and safety of percutaneous image-guided cryoablation of abdominal wall endometriosis.

PURPOSE: To evaluate the feasibility and safety of percutaneous image-guided cryoablation of abdominal wall endometriosis (AWE). MATERIALS AND METHODS: A retrospective review of percutaneous cryoablation (CT or MR) of AWE was performed from January 2018 to December 2020. Eighteen patients were identified from an internal percutaneous ablation database. Technical success, complications, and outcomes were analyzed according to standard nomenclature. RESULTS: Patients comprised 18 females (mean age 36.9 years) who underwent 18 cryoablation procedures to treat 23 AWE deposits. Three of the 18 cases were performed under MR guidance, while the remaining 15 employed CT guidance. Technical success was achieved in all 18 cases (100%). Fifteen of 18 patients (83%) had biopsy proven AWE deposits prior to treatment. Hydrodisplacement was used to displace adjacent bowel, bladder, or neurovascular structures in 13/18 cases (72%). The mean number of probes used per case was 3. Sixteen of 23 (70%) of AWE deposits had imaging follow-up (median 85 days). Of the 16 lesions with imaging follow-up, 15 (94%) demonstrated no residual enhancement or T1 hyperintensity at the treatment site and 1 lesion (6%) demonstrated residual/progressive disease. At clinical follow-up, 13 of 14 (93%) patients reported improvement in AWE-related symptoms. Eleven patients had clinically documented pain scores before and after ablation and all demonstrated substantial symptomatic improvement. No society of interventional radiology (SIR) major complications were observed. CONCLUSIONS: Percutaneous cryoablation of AWE is feasible with a favorable safety profile. Further longitudinal studies are needed to document durable response over time.

Dual contrast liver MRI: a pictorial illustration.

Liver magnetic resonance imaging (MRI) is a commonly performed imaging technique with multiple indications and applications. There are two general groups of contrast agents used when imaging the liver, extracellular contrast agents (ECA) and hepatobiliary agents (HBA), each of which has its own advantages and limitations. Liver MRI with ECA provides excellent information on abdominal vasculature and better quality multi-phasic studies for characterization of focal liver lesions. HBA improves lesion detection, provides information regarding liver function and can be helpful for evaluating biliary tree anatomy, excretion, anastomotic stenoses, or leaks. Most liver MRI studies are usually performed with one agent, however in some cases, a second study is performed with another agent to obtain additional information or confirm the findings in the first study. Administering both agents in a single exam can potentially eliminate the need for additional imaging in certain situations. In this pictorial review, the techniques and indications for dual contrast MRI will be detailed with multiple demonstrative examples.

Imaging of gastrointestinal endometriosis: what the radiologist should know.

Deep invasive gastrointestinal endometriosis (DIGIE) is a frequent and severe presentation of endometriosis. Although most cases invade the rectosigmoid colon, DIGIE can involve any portion of the gastrointestinal tract from the stomach to the rectum, and is commonly multifocal and multicentric. Although histopathologic confirmation with surgery remains the gold standard for diagnosis, ultrasound (US) and magnetic resonance imaging (MRI) are the key non-invasive imaging modalities for initial assessment. US may be preferred as a screening study because of its easy availability and low-cost. Pelvic MRI and magnetic resonance enterography (MRE) provide substantial advantages for disease mapping in the pre-operative period, particularly in extensive bowel endometriosis. Although medical management of DIGIE with hormonal therapy can help control symptoms, disease course can be relentless and require surgical intervention. Surgical options depend on, the location; length; depth; circumference; multicentric or multifocal disease. With procedures including simple excision, fulguration of superficial lesions, shaving, disc excision, and segmental resection. A successful treatment outcome is largely dependent on good communication between the treating surgeon and the radiologist, who can provide vital information for effective surgical planning by reporting the key elements that we elaborate upon in this paper.

Recommendations for MRI technique in the evaluation of pelvic endometriosis: consensus statement from the Society of Abdominal Radiology endometriosis disease-focused panel.

Endometriosis is a common entity causing chronic pain and infertility in women. The gold standard method for diagnosis is diagnostic laparoscopy, which is invasive and costly. MRI has shown promise in its ability to diagnose endometriosis and its efficacy for preoperative planning. The Society of Abdominal Radiology established a Disease-Focused Panel (DFP) to improve patient care for patients with endometriosis. In this article, the DFP performs a literature review and uses its own experience to provide technical recommendations on optimizing MRI Pelvis for the evaluation of endometriosis.

MRI impacts endometriosis management in the setting of image-based multidisciplinary conference: a retrospective analysis.

PURPOSE: The aim of the study was to quantify the value of pre-operative magnetic resonance imaging (MRI) in guiding surgical management of women with endometriosis. METHODS: Pre-operative discussion of patient management and review of imaging occurred for 136 patients with endometriosis in an MRI-based multidisciplinary conference co-directed by an abdominal radiologist and gynecologic surgeon. A tri-compartmental report template guided the systematic imaging review. Management changes made as a result of the conference were identified via retrospective chart review and classified as major, directly influencing the surgical procedure or approach, or minor, impacting the patient's medical management, therapies, or diagnostic evaluation. RESULTS: Of the 136 patients discussed in conference, a management change was identified in 18.4% (25 patients). Major changes occurred in 8.1% (11 patients) and minor changes in 13.2% (18 patients). The sum of major and minor management changes exceeded the total, as both major and minor management changes were made for 4 patients. CONCLUSION: Our findings demonstrate the ability of an MRI-based multidisciplinary conference to result in pre-operative management changes in approximately 1 of 5 pre-operatively reviewed women with endometriosis. Importantly, systematic review of the MRI facilitated management changes beyond that of the dictated report alone, which was available to clinicians prior to the conference. The study reflects the value of multidisciplinary interaction, with radiologists serving more directly as clinical consultants to surgical services, and suggests an opportunity to optimize the role of MRI in endometriosis management with standardized reports emphasizing surgically pertinent findings.

Imaging Findings of Ileal Inflammation at Computed Tomography and Magnetic Resonance Enterography: What do They Mean When Ileoscopy and Biopsy are Negative?

BACKGROUND AND AIMS: Our goal was to determine the importance of ileal inflammation at computed tomography or magnetic resonance enterography in Crohn's disease patients with normal ileoscopy. METHODS: Patients with negative ileoscopy and biopsy within 30 days of CT or MR enterography showing ileal inflammation were included. The severity [0-3 scale] and length of inflammation within the distal 20 cm of the terminal ileum were assessed on enterography. Subsequent medical records were reviewed for ensuing surgery, ulceration at ileoscopy, histological inflammation, or new or worsening ileal inflammation or stricture on enterography. Imaging findings were classified as: Confirmed Progression [subsequent surgery or radiological worsening, new ulcers at ileoscopy or positive histology]; Radiologic Response [decreased inflammation with medical therapy]; or Unlikely/Unconfirmed Inflammation. RESULTS: Of 1471 patients undergoing enterography and ileoscopy, 112 [8%] had imaging findings of inflammation with negative ileoscopy, and 88 [6%] had negative ileoscopy and ileal biopsy. Half [50%; 44/88] with negative biopsy had moderate/severe inflammation at enterography, with 45%, 32% and 11% having proximal small bowel inflammation, stricture or fistulas, respectively. Two-thirds with negative biopsy [67%; 59/88] had Confirmed Progression, with 68%, 70% and 61% having subsequent surgical resection, radiological worsening or ulcers at subsequent ileoscopy, respectively. Mean length and severity of ileal inflammation in these patients was 10 cm and 1.6. Thirteen [15%] patients had Radiologic Response, and 16 [18%] had Unlikely/Unconfirmed Inflammation. CONCLUSION: Crohn's disease patients with unequivocal imaging findings of ileal inflammation at enterography despite negative ileoscopy and biopsy are likely to have active inflammatory Crohn's disease. Disease detected by imaging may worsen over time or respond to medical therapy.

Percutaneous cryoablation of abdominal wall endometriosis: the Mayo Clinic approach.

Abdominal wall endometriosis (AWE) is a rare form of endometriosis that often results in substantial pain and debility. The current treatment algorithm for AWE is not well established. The purpose of this review is to describe the Mayo Clinic experience with thermal ablation of symptomatic AWE as well as to review current imaging and interventional literature regarding the diagnosis and treatment of AWE.

Comparison of routine pelvic US and MR imaging in patients with pathologically confirmed endometriosis.

PURPOSE: To estimate the benefit of pelvic magnetic resonance (MR) imaging after routine pelvic ultrasound (US) in patients with pathologically or surgically proven endometriosis. METHODS: Patients with surgically or pathologically proven endometriosis who had routine pelvic US followed by pelvic MR within 6 months prior to surgery were included. Patients were excluded if they had previously confirmed endometriosis, pregnancy, or surgery > 6 months after MR. The detection rate of endometriosis by pelvic US and MR was compared to the surgical/pathological reference standard. RESULTS: 83 female patients (mean age 40 ± 9) met inclusion criteria and had surgical/pathological confirmation of endometriosis. The mean time interval between pelvic US and MR was 33 ± 43 days, with 64 ± 69 days between MR examination and surgery. US detected endometriosis in 22% (18/83) of patients compared to 61% (51/83) for MR (p < 0.0001). 51% (33/65) of patients with a negative pelvic US exam had a positive MR. MR identified additional sites or sequela in the majority of patients with a positive US (14/18; 78%), including extraovarian locations [e.g., fallopian tubes 7/18 (39%), uterus 7/18 (39%), uterine ligaments 6/18 (33%), posterior cul de sac 5/18 (28%), pelvic side walls 5/18 (28%), abdominal wall 1/18 (6%)] and sequela [ovarian tethering 5/18 (28%), 6/18 (33%) bowel adhesive disease, posterior cul de sac obliteration 2/18 (11%), hydrosalpinx 2/18 (11%), and hydronephrosis 1/18 (6%)]. 3 T MR detected endometriosis in 33/46 (72%) patients compared to 18/37 (49%) for 1.5 T MR (p = 0.03). CONCLUSION: Pelvic MR imaging had a higher detection rate of surgically/pathologically proven endometriosis and provides more information about disease location and sequela compared to routine pelvic US.

Endometriosis in the postmenopausal female: clinical presentation, imaging features, and management.

Postmenopausal endometriosis is an important clinical entity which is likely under-recognized and in which the Radiologist can play a valuable role. In this review, we describe the clinical presentation and management of postmenopausal endometriosis, appraising the literature and providing case examples. Persons with postmenopausal endometriosis may present with symptoms including pelvic pain or dyschezia, but endometriosis may also be an asymptomatic, incidental finding. Women may or may not have a prior history of endometriosis or a history of symptoms consistent with it. Therapies and conditions which increase exogenous or endogenous estrogen, respectively, increase the risk. Endometriosis can be found in different locations throughout the body, and the possibility of malignancy should be assessed, especially in the postmenopausal population, where age increases cancer risk. Treatment may involve surgery or medical interventions. Guidelines describing appropriate imaging surveillance in these patients are lacking. In the postmenopausal population, Radiologists need to consider endometriosis as a diagnosis, recommend appropriate exams such as MRI and US, and suggest endometriosis-associated malignancies when appropriate, based on classic morphologic features.

Understanding malignant transformation of endometriosis: imaging features with pathologic correlation.

PURPOSE: Transformation of benign endometriosis to endometriosis-associated ovarian carcinoma (EAOC) is rare; however, women with endometriosis are four times more likely to develop EAOC which can present 20 years earlier than de novo ovarian cancer. Presenting symptoms are often vague and the radiologist's role in recognizing EAOC is critical for early detection and treatment. Histopathologic evaluation remains the mainstay for definitive diagnosis. METHODS: Using a case-based approach, this article will review the sonographic, CT, and MRI features of EAOC with an emphasis on MRI. Histopathologic correlation of benign and malignant endometriosis will be reviewed. RESULTS: Multiple factors contribute to the malignant transformation of endometriosis including genetic alterations, hormonal influences, oxidative stress, and inflammation. Malignancy most often occurs in ovarian endometriomas with less common sites involving the rectovaginal septum, rectosigmoid colon, and abdominal wall scars. The most common pathologic subtypes are endometrioid adenocarcinoma and clear cell carcinoma. MRI is the most specific imaging modality for evaluating EAOC. Key MR features include solid enhancing nodules (accentuated by subtraction imaging), nodular septations, loss of T2 shading within the endometrioma, and diffusion restriction. CONCLUSIONS: EAOC is a distinct disease that affects women with benign endometriosis at younger ages than classic ovarian cancer. Understanding the imaging features of malignant transformation of endometriosis is essential for early diagnosis and timely definitive treatment.

Association between kissing and retropositioned ovaries and severity of endometriosis: MR imaging evaluation.

PURPOSE: To retrospectively investigate the relationship between ovarian positioning on pre-operative MR imaging and intra-operative staging of endometriosis. MATERIALS AND METHODS: Sixty-five women with suspected endometriosis who underwent pre-operative MRI and subsequent intra-operative staging of endometriosis formed the study group. A trained senior radiology resident and a board-certified staff radiologist experienced in endometriosis reviewed MR images for ovarian positioning and the presence of an endometrioma. The position of the ovaries was classified as (a) kissing when they were posterior to the uterus and in contact, (b) retropositioned when they were posterior to the uterus but not in contact, or (c) normal. Intra-operative staging of endometriosis (stage 0 to IV) was determined using the revised American Society for Reproductive Medicine classification system (rASRM) by a surgeon with expertise in endometriosis surgery. Correlation between ovarian positioning and endometriosis stage was evaluated with a logistical regression analysis. Sensitivity, specificity, and accuracy were calculated. RESULTS: MR images revealed kissing ovaries in 12 women, retropositioned ovaries in 17 women, and normally positioned ovaries in 36 women. At surgery, endometriosis stages 0, I, II, III, and IV were found in 13, 15, 6, 9, and 22 patients, respectively. The odds of stage IV endometriosis were eight times higher given kissing or retropositioned compared to normal ovaries, regardless of the presence of an endometrioma (p =0.01). Kissing and retropositioned ovaries had an accuracy of 82% for stage IV endometriosis, with 86% sensitivity and 79% specificity. All cases with kissing ovaries had stage III/IV endometriosis. CONCLUSIONS: Kissing and retropositioned ovaries on pre-operative MR images are associated with higher intra-operative rASRM stages of endometriosis.