Versatile Role of 18 F-FDG PET/CT in a Patient with Pan-cerebellar Paraneoplastic Manifestation Due to Underlying Hodgkin’s Lymphoma / 대한핵의학회잡지

Hodgkin’s lymphoma most commonly presents as painless lymphadenopathy and systemic B symptoms like fever, night sweats, and weight loss. But rarely, it can present with unusual paraneoplastic manifestations. In the present case, we report a 30-year-old woman who presented with sub-acute onset pan-cerebellar symptoms. The serum neuronal antibody panel was negative. She underwent F-18 FDG PET/CT to evaluate the neoplastic etiology as the underlying cause, which demonstrated both the primary etiology and the paraneoplastic changes in the brain.

Incremental Role of ¹⁸FDG PET/CT in Assessment of Testicular Viability / 대한핵의학회잡지

Testicular torsion is a common differential diagnosis of acute scrotal pain along with acute epididymo-orchitis, which may lead to testicular non-viability. Doppler ultrasound and testicular scintigraphy are two routinely used modalities for the assessment of testicular viability. However, in some cases, these investigations may prove inadequate in differentiating between the two entities with widely differing management. Here, we present a case of a 52-year-old male with questionable viability of testis, who was investigated initially using testicular scintigraphy and was further subjected to a regional 18F-FDG PET/CT scan, in view of inconclusive findings with the conventional modalities.

Langerhans' Cell Histiocytosis Masquerading as Metastatic Papillary Thyroid Cancer on F-18 FDG PET/CT: Diagnostic Dilemma Solved by PET/CT-Guided Biopsy / 대한핵의학회잡지

We present a case of papillary thyroid cancer (post-thyroidectomy status) on regular treatment with suppressive Levothyroxine therapy. On follow-up at 6 months after radioactive iodine ablation for remnant thyroid tissue, her thyroglobulin, and anti-thyroglobulin levels were 0.06 ng/ml and 670 IU/ml, respectively. Low-dose whole-body I-131 scan was negative. To look for the cause of isolated increased anti-thyroglobulin level, a whole-body ¹⁸F-FDG PET/CT was done which revealed multiple FDG-avid lytic skeletal lesions suggestive of metastases. For confirmation of diagnosis, ¹⁸F-FDG PET/CT-guided metabolic biopsy was done, which revealed Langerhans' cell histiocytosis on histopathological examination.

Incremental Role of ¹⁸FDG PET/CT in Assessment of Testicular Viability / 대한핵의학회잡지

Testicular torsion is a common differential diagnosis of acute scrotal pain along with acute epididymo-orchitis, which may lead to testicular non-viability. Doppler ultrasound and testicular scintigraphy are two routinely used modalities for the assessment of testicular viability. However, in some cases, these investigations may prove inadequate in differentiating between the two entities with widely differing management. Here, we present a case of a 52-year-old male with questionable viability of testis, who was investigated initially using testicular scintigraphy and was further subjected to a regional 18F-FDG PET/CT scan, in view of inconclusive findings with the conventional modalities.

Langerhans' Cell Histiocytosis Masquerading as Metastatic Papillary Thyroid Cancer on F-18 FDG PET/CT: Diagnostic Dilemma Solved by PET/CT-Guided Biopsy / 대한핵의학회잡지

We present a case of papillary thyroid cancer (post-thyroidectomy status) on regular treatment with suppressive Levothyroxine therapy. On follow-up at 6 months after radioactive iodine ablation for remnant thyroid tissue, her thyroglobulin, and anti-thyroglobulin levels were 0.06 ng/ml and 670 IU/ml, respectively. Low-dose whole-body I-131 scan was negative. To look for the cause of isolated increased anti-thyroglobulin level, a whole-body ¹⁸F-FDG PET/CT was done which revealed multiple FDG-avid lytic skeletal lesions suggestive of metastases. For confirmation of diagnosis, ¹⁸F-FDG PET/CT-guided metabolic biopsy was done, which revealed Langerhans' cell histiocytosis on histopathological examination.

Is [F-18]-fluorodeoxyglucose FDG-PET/CT better than ct alone for the preoperative lymph node staging of muscle invasive bladder cancer?

OBJECTIVE: To evaluate whether the use of [F-18]-FDG-PET/CT can accurately predict pelvic lymph node metastasis in patients with muscle invasive TCC of the bladder undergoing radical cystectomy. MATERIALS AND METHODS: Fifteen patients with muscle invasive bladder cancer had undergone FDG-PET/CT scan from the skull base to the mid-thighs after IV injection of 6.5MBq (Mega-Becquerel)/Kg of FDG. After intravenous hydration IV furosemide was given to overcome the difficulties posed by urinary excretion of 18F-FDG. PET/ CT data were analyzed as PET and CT images studied separately as well as fused PET/ CT images. The imaging findings were correlated with the histopathology of the nodes (gold standard). RESULTS: CT and FDG-PET had demonstrated positive lymph nodes in 9 & 8 patients respectively. Among the 15 patients 3 had documented metastasis on histopathology. Both CT and PET could detect the nodes in all these 3 patients (100% sensitivity). Nodes were histologically negative amongst 6&5 patients who had node involvement by CT and PET respectively. Therefore, specificity, positive predictive value (PPV) & negative predictive value (NPV) for CT and PET/CT were 50%, 33.3%, 100% and 58.3%, 37.5%, 100% respectively. CONCLUSION: The theoretical advantage of this cutting edge technology for whole body imaging has not been translated into clinical practice as we found minimal advantage of combined FDG-PET/CT over CT alone for nodal staging of muscle invasive bladder cancer. This may be due to substantial overlap between standardized uptake values (SUVs) from active inflammatory processes with those of malignant lesion.

Is [F-18]-fluorodeoxyglucose FDG-PET/CT better than ct alone for the preoperative lymph node staging of muscle invasive bladder cancer?

ABSTRACT Objective: To evaluate whether the use of [F-18]-FDG-PET/CT can accurately predict pelvic lymph node metastasis in patients with muscle invasive TCC of the bladder undergoing radical cystectomy. Materials and Methods: Fifteen patients with muscle invasive bladder cancer had undergone FDG-PET/CT scan from the skull base to the mid-thighs after IV injection of 6.5MBq (Mega-Becquerel)/Kg of FDG. After intravenous hydration IV furosemide was given to overcome the difficulties posed by urinary excretion of 18F-FDG. PET/CT data were analyzed as PET and CT images studied separately as well as fused PET/CT images. The imaging findings were correlated with the histopathology of the nodes (gold standard). Results: CT and FDG-PET had demonstrated positive lymph nodes in 9 & 8 patients respectively. Among the 15 patients 3 had documented metastasis on histopathology. Both CT and PET could detect the nodes in all these 3 patients (100% sensitivity). Nodes were histologically negative amongst 6&5 patients who had node involvement by CT and PET respectively. Therefore, specificity, positive predictive value (PPV) & negative predictive value (NPV) for CT and PET/CT were 50%, 33.3%, 100% and 58.3%, 37.5%, 100% respectively. Conclusion: The theoretical advantage of this cutting edge technology for whole body imaging has not been translated into clinical practice as we found minimal advantage of combined FDG-PET/CT over CT alone for nodal staging of muscle invasive bladder cancer. This may be due to substantial overlap between standardized uptake values (SUVs) from active inflammatory processes with those of malignant lesion.

99mTc-MDM Brain SPECT for the Detection of Recurrent/Remnant Glioma-Comparison With ceMRI and 18F-FLT PET Imaging: Initial Results.

PURPOSE: To evaluate the diagnostic use of an indigenously developed single vial ready to label (with Tc) kit preparation of bis-methionine-DTPA (Tc-MDM) for the detection of recurrent/residual glioma. MATERIALS AND METHODS: We prospectively studied 32 patients (21 male and 11 female subjects aged 43.0±16.0 years) with clinical suspicion of postoperative recurrent/residual glioma. After radical radiotherapy (54.0-60.0 Gy) with or without concurrent temozolomide as indicated, Tc-MDM SPECT and ceMRI of the brain was performed in all the patients and F-FLT-PET imaging in 16 of 32 patients. RESULTS: MDM SPECT and ceMRI findings were concordant in 28 patients (15 positive and 13 negative). The findings were discordant in the remaining 5 patients, with positive ceMRI and negative MDM-SPECT in 2 patients and negative ceMRI and positive MDM-SPECT in 3 patients. Tc-MDM-SPECT, F-FLT PET, and ceMRI scan findings were positive in 9 of 16 and negative in 5 of 16 patients. In the remaining 2 of 16 patients, both F-FLT-PET and Tc-MDM-SPECT were positive, but ceMRI was negative. Sensitivity, specificity, PPV, NPV, and DA of Tc-MDM-SPECT for diagnosing recurrent/residual glioma were 88.24%, 81.25%, 83.3%, 86.7%, and 84.8%, respectively. CONCLUSIONS: The diagnostic accuracy of Tc-bis-methionine (MDM)-SPECT imaging was comparable with that of ceMRI and F-FLT-PET and may be useful in the management of glioma patients in the postsurgical follow-up period. This imaging technique may be of special interest in peripheral hospitals/developing countries lacking access to expensive PET/cyclotron technology. However, comparison with the existing "gold standard" PET tracers, especially with C-11-methionine-PET imaging and histopathological correlation, is warranted in a large cohort of glioma patients through multicentric studies.

Association of angiotensin converting enzyme and angiotensin type 2 receptor gene polymorphisms with renal damage in posterior urethral valves.

OBJECTIVE: To examine the association with renal damage in patients with posterior urethral valves (PUV) of two renin-angiotensin system gene polymorphisms: angiotensin converting enzyme insertion/deletion (ACE I/D) and angiotensin type 2 receptor (AT2R A1332G), PATIENTS AND METHODS: In 120 patients with PUV, after stabilization, transurethral fulguration or a Blocksom vesicostomy was performed. Records were reviewed for age at diagnosis, biochemical renal function at diagnosis, results of urine cultures, voiding cystourethrograms, radiologic, sonographic and nuclear medicine scan findings, and follow-up data. ACE I/D genotypes were determined by the polymerase chain reaction using allele specific primers. RESULTS: The frequency of the ACE DD genotype was significantly higher in patients with chronic kidney disease (P=0.02) and renal scarring (P=0.05). These genotypes were also associated with a statistically higher incidence of vesicoureteral reflux, diurnal incontinence, proteinuria and hypertension. A significantly higher frequency of the AT2R GG genotype was found in PUV patients as compared to healthy unrelated control subjects (P=0.001), and in PUV patients with scarring (P=0.02). CONCLUSION: The ACE DD and AT2R GG genotypes are associated with chronic kidney disease and scarring in PUV patients. The GG genotype incidence is higher among PUV patients compared to the control population, and further studies in this area may help understanding of the genetic basis of PUV.