Rakesh Sajjan

18F-fluorodeoxyglucose positron emission tomography/computed tomography in diagnosis of post-transplant lymphoproliferative disorder

Abstract The aim of the present study was to investigate the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the diagnosis of post-transplant lymphoproliferative disorder (PTLD), a serious complication of solid organ and bone marrow transplant. Between January 2004 and January 2012, 40 patients (22 males; median age 52 ± 17.4 years, range 11–77 years) underwent 18F-FDG PET/CT scans in our department for diagnostic evaluation of PTLD. Twenty-three (57.5%) patients had negative 18F-FDG PET/CT and 17 (42.5%) had a positive examination. In five patients PET/CT revealed extranodal disease (adrenal, pleural, spleen, liver, lung, esophagus and bone involvement). On the basis of our results, 18F-FDG PET/CT had a sensitivity of 88.2% (95% confidence interval [CI] 0.62–0.98), a specificity of 91.3% (CI 0.70–0.98), a positive predictive value of 88.2% (CI 0.62–0.98) and a negative predictive value of 91.3% (CI 0.70–0.98). The diagnostic performance of CT in patient-based analysis was: a sensitivity of 87.5% (CI 0.60–0.97), a specificity of 88.8% (CI 0.64-0.98), a positive predictive value of 87.5% (CI 0.60–0.97) and a negative predictive value of 88.8% (CI 0.64–0.98). PET/CT in five cases revealed more findings than CT, upstaging the disease, and revealed three extranodal findings, not visualized in conventional imaging. 18F-FDG PET/CT plays a significant role in the setting of PTLD diagnosis, demonstrating its high accuracy in detecting PTLD.

Painful knee prosthesis: can we help with bone SPECT/CT?

ObjectivesThe aim of the study was to evaluate the value of single-photon emission computerized tomography/computed tomography (SPECT/CT) in the clinical assessment of painful knee prostheses. Materials and methodsBetween 2009 and 2011 we identified 105 patients who had undergone 99mTc-hydroxydiphosphonate SPECT/CT for painful knee prosthesis. Complete follow-up data were available for 69 patients (50 women and 19 men; mean age, 71 years) with painful knee prostheses (59 total, nine unicompartmental, one patellofemoral) and clinical suspicion of infection or loosening. The imaging test report in conjunction with the clinical data from the patient’s notes was used to gauge how useful the test had been in terms of patient management. ResultsSPECT/CT confirmed the suspected clinical diagnosis of loosening in nine patients (13%) and of infection in two (2.9%) and identified other causes in 43 patients (62.3%). In 85.5% of patients, SPECT/CT was clinically useful (both positive and negative results), whereas in 14.5% it had no clinical impact on patient management. Revision surgery was performed in 24/69 (34.8%) patients and confirmed the SPECT/CT diagnosis in 21 patients (seven loosening, one infection, two subchondral fractures, two postoperative inflammation and nine patellofemoral osteoarthritis). ConclusionSPECT/CT is a useful tool for the evaluation of painful knee prosthesis in 85.5% of cases and helps in confirming mechanical loosening and in excluding other causes such as infection and patellofemoral osteoarthritis.

Adolescent With 68Ga DOTATATE-Avid Vertebral Hemangioma Mimicking Metastasis in PET Imaging.

⁶⁸Ga DOTATATE PET/CT is a well-established method in the diagnostic workup of neuroendocrine tumors. We report the case of a 15-year-old adolescent boy with histologically proven appendiceal carcinoid tumor referred for ⁶⁸Ga DOTATATE PET/CT to identify residual or metastatic disease. PET images showed increased tracer uptake in the body of T4 vertebra. This uptake could be misdiagnosed for bone metastasis, but CT characteristic appearance was in keeping with vertebral hemangioma. Both bone metastasis in carcinoid tumor and bone hemangiomas in adolescents are rare conditions, but the combined metabolic and morphological information on PET/CT can lead to the correct diagnosis.

68Ga-DOTATATE PET/MR Imaging of Urinary Bladder Paraganglioma.

Paragangliomas of the urinary bladder are very rare. They are extra-adrenal autonomic nervous system tumors. This report presents a case of a 13-year-old boy with urinary bladder paraganglioma and the role of somatostatin receptor imaging with simultaneous positron emission tomography magnetic resonance (PET/MR). We have also described appearances of iodine-123 metaiodobenzylguanidine ((123)I-MIBG) single photon emission computed tomography (SPECT/CT) in comparison to somatostatin receptor imaging.

Incidental Neurofibroma on 18F-Fluorocholine PET/MR.

Neurofibromas are benign peripheral nerve sheath tumors. We described a unique case of recurrent prostate cancer with coexisting neurofibroma diagnosed on F-fluorocholine PET/MRI.

Diffuse large B cell lymphoma: cutaneous manifestation

A 47-year-old gentleman was diagnosed with diffuse B cell lymphoma. His initial presentation was skin lesions. He was then referred for patch test with a diagnosis of periorbital eczema. Later, patient developed varicose veins and skin lesions in the right leg which was operated upon with poor healing and subsequent skin biopsy of the lesions demonstrated diffuse large B cell lymphoma (DLBCL). The bone marrow biopsy proved marrow involvement. He had no B symptoms. His past medical history includes brain abscess aged 9 …