Postoperative spinal subdural hygroma without incidental durotomy: illustrative cases

BACKGROUND Spinal subdural hygroma (SSH) is a rare pathological entity occurring as a complication of spinal surgery. It is different from spinal subdural hematoma due to blunt trauma, anticoagulation therapy, spinal puncture, and rupture of vascular malformations. OBSERVATIONS The authors presented five patients with SSH who received decompression for lumbar stenosis. None had incidental durotomy. All presented postoperatively with unexpectedly severe symptoms, including back and leg pain and weakness. Postoperative magnetic resonance imaging (MRI) revealed SSH with a characteristic imaging finding termed the “flying bat” sign. Four patients underwent evacuation of SSH, with immediate and complete resolution of symptoms in three patients and improvement in one patient. One patient improved without additional surgery. At surgery, subdural collections were found to be xanthochromic fluid in three patients and plain cerebrospinal fluid (CSF) in one patient. LESSONS Unexpectedly severe back and leg pain and weakness after lumbar or thoracic spine surgery should raise suspicion of SSH. MRI and/or computed tomography myelography shows the characteristic findings termed the flying bat sign. Surgical evacuation is successful although spontaneous resolution can also occur. The authors hypothesized that SSH is due to CSF entering the subdural space from the subarachnoid space via a one-way valve effect.

Mueller Weiss syndrome, a less elucidated and unusual cause of midfoot pain: A case report

Mueller Weiss Syndrome is a rare, under-diagnosed cause of chronic mid foot pain despite having well-described imaging features. It is historically described as spontaneous adult-onset osteonecrosis of the navicular bone. The disease commonly affects bilateral navicular bones in women in the fifth decade of life. Nearly a century after its first description as a disease entity, the exact etiopathogenesis is still not well understood. From a radiographic point of view weight-bearing radiographs of the foot remains the mainstay in diagnosis. Characteristic imaging findings include the lateral collapse of navicular, dorsomedial subluxation of the remnant navicular, and lateral deviation of the talus (hind-foot varus). Progressive disease leads to pes planus and secondary osteoarthritis of the talonavicular joint with or without the involvement of other midfoot joints. Severe disease may show “listhesis navicularis” and talo-cuneiform neo-articulation. Computed tomography and magnetic resonance imaging can be used as adjuncts, especially to detect changes in the initial stage of the disease and early osteoarthritic features.

A case report: Characteristic plain radiographic findings of a displaced abomasum in a heifer

A 9-month-old Holstein heifer with a history of severely poor growth presented with diarrhoea. On physical examination, a metallic pinging sound was heard on the simultaneous percussion and auscultation of the left trunk. On the cranial abdominal radiography, the contour of a gas-filled balloon-like abomasum wall was delineated, which elevated to the dorsal abdomen. Radiopaque sand at the bottom of the abomasum had been pulled up caudodorsally by the gas-filled abomasum. After surgery, the gas-filled balloon-like appearance of the abomasum wall disappeared and the radiopaque sand was located in the normal position. To our knowledge, no reports on a displaced abomasum on plain radiographs are available. The radiographic findings described herein are characteristic imaging findings of a displaced abomasum. Abdominal radiography could be a new option as an auxiliary diagnostic approach for a displaced abomasum.

Imaging diagnosis of autoimmune pancreatitis: computed tomography and magnetic resonance imaging

Autoimmune pancreatitis (AIP) is a pancreatic phenotype of IgG4-related systemic disease. Since its first description in the literature, characteristic imaging features have gradually become known to many clinicians encompassing various specialties in the past quarter century. CT and MRI have been the workhorses for imaging diagnosis of AIP. Typical features include sausage-like swelling of the focal or entire pancreas, duct-penetrating sign, a capsule-like rim of the affected lesions, and homogeneous delayed enhancement or enhanced duct sign after contrast administration, as well as characteristic combined findings reflecting coexisting pathologies in the other organs as a systemic disease. In this review, recent and future developments in CT and MRI that may help diagnose AIP are discussed, including restricted diffusion and perfusion and increased elasticity measured using MR.

Radiologic imaging findings of pelvic aggressive angiomyxoma correlated with surgical and pathological features

Background Aggressive angiomyxoma is an infrequent benign tumor that usually occurs in the pelvic region. Pelvic masses have variety of differential diagnosis but some featured findings should prompt the diagnosis of aggressive angiomyxoma by the radiologist. Case presentation A 40-year-old female patient presented with a two-year history of perineal swelling. Radiological examination including gray scale and color Doppler ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) was consistent with the diagnosis of aggressive angiomyxoma. The patient underwent surgical operation that ensures total resection of the tumor. Conclusion In the case of extensive pelvic soft tissue mass with characteristic imaging findings, the radiologists should take the diagnosis of aggressive angiomyxoma into consideration.

Hematopoietic Islands Mimicking Osteoblastic Metastases in Axial Skeleton

Background. Hyperplasia of the hematopoietic bone marrow in the appendicular skeleton is common. Focal hematopoietic islands within the axial skeleton is a rare entity and can cause confusion with osteoblastic metastases. The purpose of this study was to describe the characteristic imaging findings in MRI and CT.Methods. We retrospectively analyzed the imaging findings of 14 hematopoietic islands of the axial skeleton in ten patients (nine females, median age= 65.5 years [range, 49-74]), who received both CT and MRI at the time of initial diagnosis between 2006 and 2020. In five cases CT-guided biopsy was performed to confirm the diagnosis, while the other five patients received long term MRI follow-up (median follow-up= 28 months [range, 6-96 months]). Diffusion-weighted imaging was available in three, chemical shift imaging in two, 18F fluorodeoxyglucose PET/CT in two and Technetium 99m skeletal scintigraphy in one of the patients.Results. All lesions were small (mean size=1.72 cm2) and showed moderate hypointense signals on T1- and T2-weighted MRI sequences. They appeared iso- to slightly hyperintense on STIR images and showed slight enhancement after gadolinium administration. To differentiate this entity from osteoblastic metastases, CT provides important additional information, as hematopoietic islands do not show sclerosis. Conclusions. Hematopoietic islands within the axial skeleton can occur and mimic osteoblastic metastases. However, the combination of MRI and CT allows for making the correct diagnosis.

Partial Renal Transplant Torsion as a Cause of Abdominal Pain

Allograft torsion is a rare but potentially devastating outcome of renal transplantation. Patients typically present with an acute onset of abdominal pain, though symptoms are non-specific and can easily be missed in favor of more common diagnoses. Imaging, in particular ultrasound and computed tomography, can aid in the diagnosis of renal transplant torsion by demonstrating characteristic features, and once recognized immediate surgery is typically performed in an attempt to salvage the allograft. However, renal transplant torsion needs not be an acute event; patients can instead present with chronic, waxing, and waning symptoms if the allograft undergoes partial or intermittent torsion. The aforementioned characteristic imaging findings may not be present in this situation. It is essential to recognize partial, intermittent torsion as well, for which imaging can again play a role.

Focal Parenchymal Atrophy of the Pancreas Is Frequently Observed on Pre-Diagnostic Computed Tomography in Patients with Pancreatic Cancer: A Case-Control Study

Pancreatic ductal adenocarcinoma (PDAC) accounts for the majority of all pancreatic cancers and is highly lethal. Focal parenchymal atrophy (FPA) of the pancreas has been reported as a characteristic imaging finding of early PDAC. Here, we reviewed 76 patients with PDAC who underwent computed tomography (CT) between 6 months and 3 years before PDAC diagnosis, as well as 76 sex- and age-matched controls without PDAC on CT examinations separated by at least 5 years. FPA was observed corresponding to the location of the subsequent tumor on pre-diagnostic CT in 14/44 (31.8%) patients between 6 months and 1 year, 14/51 (27.5%) patients between 1 and 2 years, and 9/41 (22.0%) patients between 2 and 3 years before PDAC diagnosis. Overall, FPA was more frequently observed in patients with PDAC (26/76; 34.2%) on pre-diagnostic CT than that in controls (3/76; 3.9%) (p < 0.001). FPA was observed before the appearance of cut-off/dilatation of the main pancreatic duct, suggesting that FPA might be the earliest sign of PDAC. FPA was less frequently found in tumors in the pancreatic head (3/27; 11.1%) than in those in the body (14/30; 46.7%) or tail (9/19; 47.4%). FPA may predict the subsequent PDAC diagnosis, serving as an important imaging sign for the early diagnosis of pancreatic cancer.

Imaging in a case of classic Trevor’s disease

Trevor’s disease, also known as dysplasia epiphysealis hemimelica, is a rare developmental bone dysplasia, characterized by benign osteocartilaginous overgrowth pathologically indistinguishable from osteochondroma. The lesion arises from epiphysis more so on the medial aspect of long bones resulting in painless or painful deformities and limb length discrepancies. Imaging plays an important role in diagnosis as the features are characteristic in an appropriate demographic background. We report a case of Trevor’s disease in a 2-year male with multifocal involvement and characteristic imaging findings.