Using marker-controlled watershed transform to detect baker’s cyst in MRI images: a pilot study

Introduction: Nowadays, Magnetic resonance imaging (MRI) has a high ability to distinguish between soft tissues because of high spatial resolution. Image processing is extensively used to extract clinical data from imaging modalities. In the medical image processing field, the knee’s cyst (especially baker) segmentation is one of the novel research areas.Material and Method: There are different methods for image segmentation. In this paper, the mathematical operation of the watershed algorithm is utilized by MATLAB software based on marker-controlled watershed segmentation for the detection of baker’s cyst in the knee’s joint MRI sagittal and axial T2-weighted images.Results: The performance of this algorithm was investigated, and the results showed that in a short time baker’s cyst can be clearly extracted from original images in axial and sagittal planes.Conclusion: The marker-controlled watershed segmentation was able to detect baker’s cyst reliable and can save time and current cost, especially in the absence of specialists it can help us for the easier diagnosis of MR images.

Lymphangioma of popliteal fossa masquerading as Baker’s cyst

Background Lymphatic malformations are the second most common vascular malformations after venous malformations. These slow-flow lesions occur most often in the paediatric population and seldom in the extremities. We report a case of lymphangioma at the popliteal fossa in an adult who underwent complete surgical resection. Case presentation A 30-year-old male presented to the department of orthopaedics with a swelling in the right calf region. Clinically, it was suspected to be a Baker’s cyst. Ultrasound showed a multiloculated anechoic cystic lesion in the inferior aspect of popliteal fossa along the intermuscular plane with multiple internal septations. Infected Baker’s cyst was considered, and MRI was suggested for further evaluation. On MRI, the lesion measured 7.2 × 4.6 × 5.8 cm, appeared as a low signal on T1 and high signal on STIR and T2, with multiple internal septations and was situated in the inferior aspect of the right popliteal fossa along the intermuscular plane between the lateral head of gastrocnemius and soleus muscles. No obvious synovial extension. A post-contrast study showed minimal peripheral and septal enhancement. Neither internal enhancing solid components nor significant internal derangement of the knee was observed. Diagnosis of lymphangioma was considered based on the imaging features and ruling out the common differentials for cystic lesions around the knee. Wide local excision was performed. Histopathological evaluation showed multiple irregularly dilated lymphatic channels lined by flatted epithelium. The lymphatic channels were seen to be surrounded by thick fibro collagenous cyst wall with scattered congested blood vessels, skeletal muscle fibre and chronic inflammatory cells. Conclusion Lymphangioma must be included in the differential diagnosis of any cystic lesion if the lesion appears multiseptated and/or infiltrative. At the popliteal fossa, it presents as a multiseptated cyst with no synovial continuity or internal derangement of the knee.

Ruptured Popliteal Cysts Mimicking Deep Vein Thrombosis in Well-functioning Total Knee Replacements: Report of Two Cases and Review of Literature

Introduction: Implant wear and loosening with eluding metal/polythene debris are commonly implicated in the occurrence of Baker’s cysts in post-operative total knee replacement (TKR) patients, who present with post-operative pain and swelling, mimicking deep venous thrombosis. However, we present two symptomatic cases presenting with ruptured Baker’s cysts post-TKRs, with no evidence of implant loosening or wear. Cases Report: The 1st patient was a 55-year-old male, who underwent TKR for Grade 4 bilateral knee osteoarthritis and presented with acute onset of pain and swelling over the left popliteal fossa, which progressed to involve the calf. Radiographs showed no sign of infection or loosening, and venous color Doppler and magnetic resonance imaging (MRI) showed a hy-poechoic collection in the intermuscular plane at the upper part of popliteal fossa. Histological examination of the aspirated fluid showed mixed features of cystic fluid and a resolving hematoma. There was complete resolution of the 4 months with rest and graduated physiotherapy. The 2nd patient was a 51-year-old female who developed the cystic swelling 2 years after the surgery, and the ultrasound showed hypoechoic echoes in a Baker’s cyst-like collection. Cytological findings were suggestive of hemorrhagic nature of the aspirate, without any evi-dence of polyethylene debris, and the cultures were sterile. She became asymptomatic over 4 weeks with conservative management; the swelling resolved after 3 months. Conclusion: Majority of the cases in literature show implant loosening as cause of popliteal cysts after TKRs, however present cases highlight alternative mechanisms, and there are good chances of self-resolution of cysts with conservative treatment in such cases. Keywords: Knee replacement, Baker’s cyst, deep vein thrombosis, ruptured popliteal cyst.