The sacroiliac joint (SIJ) is a critical anatomic structure that connects the axial skeleton with the lower limbs. Compared with its adult counterpart, the pediatric SIJ exhibits unique anatomic features, and imaging evaluation may then present significant challenges due to overlapping features between normal developmental manifestations, anatomic variants, and true pathologic conditions. Two frequently observed developmental findings can resemble pathologic conditions: subchondral irregularities and subchondral flaring. These are commonly seen on MR images of the developing pelvis. A diverse range of anatomic variations has been documented in both the cartilaginous and ligamentous components of the SIJ. Though overall innocuous, some variations are linked to mechanical overload and pain. True sacroiliitis can arise from inflammatory, infectious, or traumatic causes. Inflammatory conditions may exhibit similar imaging characteristics and are best differentiated through MRI. The presence of unilateral sacroiliitis should prompt consideration of an infectious cause, with imaging indicators such as capsular edema and abscess formation suggesting infection. Traumatic injuries to the SIJ are uncommon in children and usually occur in the context of high-energy trauma. Mechanical overload or repetitive stress in the pediatric population can result in bone marrow edema in the weight-bearing regions of the SIJ and, less commonly, in sacral stress fractures, most often involving the sacral ala. It is crucial to accurately differentiate these imaging features to avoid functional impairments, morbidity, and unnecessary interventions. The authors aim to enhance radiologists' understanding of the pediatric SIJ by examining its unique anatomic characteristics, key imaging features, and pertinent differential diagnosis. © RSNA, 2026 Supplemental material is available for this article.

Small bowel herniation through a Caesarean section wound is exceedingly rare and may present with erythema and induration clinically indistinguishable from superficial wound infection, risking dangerous diagnostic delay. A case is reported here of a 39-year-old woman with one prior Caesarean section and a body mass index of 30 kg/m2 who underwent elective lower segment Caesarean section at 39 weeks of gestation, complicated by intraoperative adhesiolysis and decompression of a uterovesical fatty cyst. On postoperative day 3, the patient re-presented with right iliac fossa pain, vomiting, and extensive blanching erythema extending to the right anterior superior iliac spine. The wound appeared clean and intact; the patient remained apyrexial with markedly elevated inflammatory markers. Initial assessment suggested cellulitis. Computed tomography of the abdomen and pelvis revealed herniation of the small bowel through the Caesarean section wound with early obstructive features. Examination under anaesthesia confirmed small bowel herniating through a rectus divarication with proximal distension. Hydrodissection and adhesiolysis enabled complete reduction; colorectal inspection confirmed viable bowel throughout; no resection was required. Omental patching and layered fascial repair were performed. The patient was discharged on postoperative day 4 without complications. The authors could find only four reports of similar cases of small bowel herniation through a Caesarean section wound; a structured series of all five reported cases is presented. Postoperative wound erythema accompanied by gastrointestinal symptoms warrants urgent computed tomography imaging to exclude bowel herniation. Early operative intervention before ischaemia develops avoids the need for bowel resection. Multidisciplinary management encompassing obstetrics, radiology, and colorectal surgery is essential; later presentations in the existing literature are consistently associated with bowel necrosis and the need for resection.

Fecalomas are hardened masses of fecal material that are a rare complication of chronic constipation and require surgical resection when conservative measures fail. Recent reports suggest that Coca-Cola, traditionally used to dissolve gastric phytobezoars, may also aid in the dissolution of fecalomas. We report the case of an 82-year-old woman with dementia, type 2 diabetes, hypertension, hypothyroidism, chronic gastritis, and depression who presented with acute abdominal pain. She had not produced stool or passed gas per rectum for several days prior to admission. Physical examination revealed middle and lower abdominal tenderness and distension. Computed tomography (CT) scan of the abdomen and pelvis demonstrated a large fecaloma (maximum diameter 12.2 cm) in the sigmoid colon and rectum, without evidence of perforation. Conservative management, including polyethylene glycol, senna, mineral oil, and sodium phosphate enemas, failed to resolve the fecaloma or the patient's symptoms. Two 1 L Classic Coca-Cola enemas were then administered, resulting in a significant reduction in the size of the fecaloma on imaging and complete resolution of symptoms. With the return of bowel function, the patient avoided surgery and was able to be discharged on a maintenance bowel regimen. This case contributes to the increasing number of reports supporting Classic Coca-Cola as an adjunct to conservative therapies for fecalomas that are refractory to conservative management.

Serous cystadenofibromas are rare benign epithelial ovarian tumors. They account for < 2% of benign ovarian tumors and typically affect individuals aged 15-65. In rare cases, these tumors present with scattered pelvic lesions resembling malignant dissemination. A 68-year-old female presented with pelvic pain. Pelvic sonogram revealed a 6 cm mass anterior to the cecum and bilateral cystic ovarian lesions measuring approximately 5 and 4 cm on the right and left, respectively. Subsequent pelvic magnetic resonance imaging (MRI) confirmed multicystic complex ovarian masses and a 6 cm multicystic mass along the cecum. Colonoscopy revealed no intrinsic rectal or sigmoid disease. She was subsequently referred to minimally invasive gynecology surgery and colorectal surgery for further management. Tumor markers and a ROMA panel were within normal limits. Computed tomography (CT) of abdomen/pelvis redemonstrated a multilobulated, cystic mass in the right lower quadrant with adjacent satellite lesions and bilateral cystic adnexal masses. Surgical intervention included robotic-assisted total laparoscopic hysterectomy, bilateral salpingo-oophorectomy, extensive lysis of adhesions, and infracolic omentectomy. Intraoperative findings revealed dense adhesions between the omentum, right adnexa, pelvic sidewall, and cecum. Frozen section revealed bilateral ovarian cystadenofibroma and omental tissue with benign cystic lesions resembling serous cystadenofibroma. Postoperatively, the patient had an uneventful recovery. Serous cystadenofibromas are associated with a favorable prognosis after complete resection of the tumor. The use of preoperative imaging and intraoperative frozen sections can help guide appropriate surgical management. However, these tumors pose diagnostic challenges due to their complex nature of adnexal masses with solid and cystic elements, often leading to misdiagnosis of malignancy. In rare cases, the presence of multiple lesions may be more consistent with multicentric development or independent primary lesions rather than true dissemination. Although malignancy must be carefully excluded, disseminated benign serous cystadenofibroma implants may radiologically and intraoperatively mimic peritoneal carcinomatosis, underscoring the importance of a broad differential diagnosis to guide intraoperative judgment and avoid overtreatment.

Biplanar videoradiography is a validated method for measuring skeletal kinematics. However, using two x-ray source-detector pairs introduces geometric constraints that can compromise image quality. The spatial configuration of the two pairs often requires a larger object-to-image distance (OID), leading to greater magnification and geometric blur. Consequently, increased magnification can limit the effective field of view, restricting multi-joint analyses. Additionally, geometric blur degrades image quality, potentially compromising subsequent bone registrations. To address this limitation, this proof-of-concept study evaluated a monoplane stereoscopic videoradiography (MSV) configuration. MSV uses two x-ray sources captured by a single detector, enabling a smaller OID. A pseudo-dynamic experiment was conducted to assess whether MSV would achieve accurate calibration and subsequent three-dimensional (3D) bone positions. A cube and pelvis phantom were rotated 360° on a turntable in 15° increments. At each increment, positions were recorded using both conventional motion capture (MOCAP) and MSV, with MOCAP acting as the reference standard. During MSV image acquisition, a lead barrier alternately blocked one x-ray source, allowing the other to project onto the detector. Calibration was performed using a bundle adjustment technique, and 3D bone positions were calculated using radiostereometric analysis and model-based tracking and compared against MOCAP. Overall, MSV achieved sub-millimeter and sub-degree accuracy. The calibration yielded a mean residual of 0.22 mm, while rotational and translational biases ranged from 0.36-1.16° and 0.22-1.23 mm, respectively, with precisions of 0.09-0.59° and 0.18-0.58 mm. These results support the feasibility of using MSV to accurately calculate skeletal positions. This approach reduces magnification and, by extension, geometric blur, opening avenues for multi-joint analyses and improved imaging of deeper joints. Future work will focus on implementing a true asynchronous MSV acquisition to extend this approach to dynamic,in vivokinematic studies.

Gallstone ileus is a rare cause of small bowel obstruction (SBO). It occurs when a gallstone passes through a cholecystoenteric fistula and obstructs the bowel. This case report aims to share our experience in managing an uncommon cause of SBO and to discuss available surgical management options, including the rationale for a staged approach in patients with significant comorbidities. We describe a 63-year-old woman with a history of hypertension, diabetes, gallstones, and uterine cancer treated with hysterectomy and radiation therapy, who presented with right upper quadrant pain and vomiting and subsequently developed signs of SBO. A computerized tomography scan of the abdomen and pelvis revealed a cholecystoduodenal fistula with evidence of a stone in the distal ileum. She subsequently underwent emergency enterolithotomy, successfully removing the stone, and was scheduled for a cholecystectomy at a later date to reduce her surgical risk. We discuss the three approaches to the surgical management of gallstone ileus-enterolithotomy alone, one-stage surgery (enterolithotomy + cholecystectomy with fistula repair), and two-stage surgery (enterolithotomy and delayed cholecystectomy with fistula repair).

Developmental dysplasia of the hip (DDH) associated with an acute proximal femoral fracture on the same side is uncommon, and performing a one-stage total hip arthroplasty (THA) with concurrent fracture stabilization in such cases poses significant technical challenges. We present a case involving a 57-year-old female with a long history of right-sided DDH who was involved in a vehicular accident, leading to acute pain in her right hip, shortening of the limb, and restricted movement. Imaging studies indicated Hartofilakidis type II DDH along with a comminuted intertrochanteric fracture of the proximal femur and a pseudoacetabulum. Utilizing thin-slice computed tomography, we created a customized three-dimensional (3D) printed model of the pelvis and proximal femur, which allowed for detailed preoperative planning. This included evaluating the acetabular bone quality, identifying the true center of the acetabulum, selecting the appropriate cup size and orientation, and strategizing the femoral osteotomy and fixation with plates and cables. A one-stage cementless THA was executed through a posterolateral approach, featuring a small hemispherical cup securely placed in the true acetabulum and a size-16 biological femoral stem anchored distally across the fracture site, followed by the application of a lateral plate and titanium cable to stabilize the proximal femoral fracture. The patient began ambulation with the assistance of a walker on postoperative day 1. At 2 months after surgery, the pain score had decreased to 1/10 on the visual analog scale (VAS), and radiographic evaluation demonstrated ongoing fracture healing. By 3 months postoperatively, the patient was pain-free (VAS 0/10), had achieved a Harris Hip Score of 92, and showed restoration of lower-limb length. Imaging confirmed fracture union and stable prosthesis positioning, and the patient had returned to work independently. This case suggests that individualized 3D printing-assisted preoperative planning may improve the feasibility and early safety of one-stage cementless total hip arthroplasty combined with internal fixation for adult DDH with an ipsilateral proximal femoral fracture, and may provide a useful reference for preoperative decision-making in similarly complex cases.