Seol Hoon Park

Subregional Patterns of Preferential Striatal Dopamine Transporter Loss Differ in Parkinson Disease, Progressive Supranuclear Palsy, and Multiple-System Atrophy

Parkinson disease (PD), progressive supranuclear palsy (PSP), and multiple-system atrophy (MSA) are known to affect dopaminergic neurons of the brain stem and striatum with different preferential involvement. Here we investigated differences in striatal subregional dopamine transporter loss in PD, PSP, and MSA and assessed the diagnostic value of 18F-fluorinated-N-3-fluoropropyl-2-β-carboxymethoxy-3-β-(4-iodophenyl)nortropane (18F-FP-CIT) PET in differentiating PSP and MSA from PD. Methods: Forty-nine patients with PD, 19 patients with PSP, 24 patients with MSA, and 21 healthy people (healthy controls) were examined with 18F-FP-CIT PET. The PET images were spatially normalized and analyzed with 12 striatal subregional volume-of-interest (VOI) templates (bilateral ventral striatum [VS], anterior caudate [AC], posterior caudate, anterior putamen, posterior putamen [PP], and ventral putamen [VP]) and 1 occipital VOI template. The nondisplaceable binding potential (BPND) and intersubregional ratio (ISR; defined as the ratio of the BPND of one striatal subregion to that of another striatal subregion) of subregional VOIs were calculated. Results: The BPND of all VOIs in the PD, MSA, and PSP groups were significantly lower than those in the healthy controls (P < 0.05). The BPND of AC and the AC/VS ISR in the PSP group were significantly lower than those in the PD group. The BPND of VP was significantly lower, but the PP/VP ISR was significantly higher in the MSA group than in the PD group. At the cutoff value for the AC/VS ISR (<0.7), the sensitivity and specificity for differentiating PSP from PD were 94% and 92%, respectively. At the cutoff value for the PP/VP ISR (>0.65), the sensitivity and specificity for differentiating MSA from PD were 90% and 45%, respectively. The diagnostic accuracy of visual analysis was similar to that of quantitative analysis for differentiating PSP from PD but was significantly higher for differentiating MSA from PD. Conclusion: Compared with PD, PSP and MSA showed more prominent and earlier dopamine transporter loss in the AC and VP, respectively. These findings could be useful for suggesting PSP or MSA in parkinsonian cases without characteristic atypical features.

(18)F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography findings are different between invasive and noninvasive pulmonary aspergillosis.

Objective Invasive pulmonary aspergillosis (IPA) is a significant cause of morbidity and mortality especially in immunocompromised patients, and extensive work has been done in the field of diagnostic imaging. The purpose of our study was to evaluate functional metabolic image findings of 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the patients with invasive and noninvasive forms of pulmonary aspergillosis (IPA and NIPA, respectively). Methods We retrospectively reviewed 24 consecutive patients who had pulmonary aspergillosis among the patients who underwent 18F-FDG PET/CT to evaluate lung mass or fever of unknown origin. Demographic feature, multiplicity, visually analyzed 18F-FDG uptake patterns (isometabolic halo, isometabolic nodule, hypermetabolic nodule, or other), and the peak standardized uptake value (SUVpeak) of the pulmonary lesions on PET/CT were evaluated. Results Of these 24 patients, 8 were diagnosed with IPA and 16 with NIPA. Patients with IPA were significantly younger (48 vs 62 years), and immunocompromised conditions were more frequently observed in these cases (88% vs 6%). Multiple lesions were noted in 50% (4 of 8) and 19% (3 of 16) of IPA and NIPA patients, respectively, and the predominant patterns on 18F-FDG PET/CT were the hypermetabolic nodule pattern (6 of 8 patients, 75%) and the isometabolic halo pattern (8 of 16 patients, 50%) in IPA and NIPA patients, respectively. The isometabolic halo pattern was not observed in IPA patients. The median SUVpeak was 4.5 (range, 1.3–8.9) and 1.6 (range, 0.5–3.1) in IPA and NIPA, respectively. Conclusions 18F-FDG PET/CT findings differ between IPA and NIPA patients. Pulmonary aspergillosis in immunocompromised status with a hypermetabolic nodule pattern on 18F-FDG PET/CT seems to have high possibility of IPA. In contrast, an isometabolic halo pattern and an isometabolic nodule pattern on 18F-FDG PET/CT seem to have high possibility of NIPA.

18F-Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography in mucosa-associated lymphoid tissue lymphoma: variation in 18F-FDG avidity according to site involvement

The purpose of this study was to determine the 18F-FDG avidity of MALT lymphoma and the additional utility of 18F-FDG PET/CT in MALT lymphoma staging. Pretreatment 18F-FDG PET/CT scans of 222 patients with 227 MALT lymphoma lesions were retrospectively analyzed. 18F-FDG avidity of lesions was noted in 28%. The proportion was lower for gastric MALT lymphomas than for non-gastric lesions (9% vs. 60%, p < 0.0001) and higher for mass-forming lesions than for superficial lesions (82% vs. 2%, p < 0.0001). 18F-FDG PET/CT showed the presence of additional lesions in 23 patients: four of six true-positive lesions had 18F-FDG avid primary lesions, and 15 of 17 false-positive lesions had 18F-FDG-non avid lesions. 18F-FDG avidity differed according to the location and gross morphologic characteristics of the MALT lymphoma. Most gastric MALT lymphomas were superficial and had low 18F-FDG avidity. For staging, 18F-FDG PET/CT can be helpful mainly for 18F-FDG avid primary MALT lymphomas.

Low-Dose Radioactive Iodine Ablation Is Sufficient in Patients With Small Papillary Thyroid Cancer Having Minor Extrathyroidal Extension and Central Lymph Node Metastasis (T3 N1a): Reply

Purpose The aim of this study was to evaluate the effectiveness of low-dose radioactive iodine (RAI) ablation in patients with small papillary thyroid cancer (PTC) exhibiting microscopic extrathyroidal extension (mETE) and central lymph node (CLN) metastasis. Methods Among patients who underwent RAI ablation between March 2007 and February 2014, those who had small PTCs (⩽2 cm), as well as mETE and CLN metastasis (T3 N1a M0), were enrolled. Response to ablation and long-term outcomes were assessed and compared according to the administered RAI dose. Factors associated with unsuccessful ablation were also determined. Results A total of 180 patients were included in the study. Eighty-eight patients had been treated with 1110 MBq (low-dose group) and 92 with 2960 MBq (high-dose group) of RAI. There were no significant differences in the responses to ablation (P = 0.810) and long-term outcomes (P = 0.663) between both groups. Among all patients enrolled, 13 did not achieve successful ablation at long-term follow-up. Logistic regression found that a high ratio of metastatic nodes was a significant factor for predicting unsuccessful ablation. Conclusions Low-dose RAI ablation did not produce significantly different responses or long-term outcomes in patients with small PTCs exhibiting mETE and CLN metastasis. These findings suggest that low-dose ablation may be sufficient in this specific group of intermediate-risk patients, although careful selection is required for patients with a high ratio of metastatic nodes.

Intravertebral vacuum cleft sign: a cause of vertebral cold defect on bone scan

A 67-year-old female presented with an acute compression fracture with an intravertebral vacuum cleft (IVC) sign of the T12 vertebra. Her bone scan demonstrated a cold defect of the fractured vertebra. Although the IVC sign is related to vertebral osteonecrosis, to the best of our knowledge, a cold defect on a bone scan has not been reported in an acute compression fracture with an IVC sign. In this case review, various imaging findings of osteonecrotic compression fractures are discussed along with a review of the current literature.

18F-FP-CIT dopamine transporter PET findings in cirrhotic patients with parkinsonism

We report the clinical features and imaging findings of presynaptic dopamine transporter (DAT) positron emission tomography (PET) in four of patients with liver cirrhosis and concurrent parkinsonism. We also reviewed previously reported cases of cirrhosis-related parkinsonism using dopaminergic molecular imaging. Our results using 18F-radiolabeled N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (FP-CIT) DAT PET in four patients with cirrhosis and parkinsonism showed two different molecular imaging patterns well related to their neurological symptoms. 18F-FP-CIT PET imaging of two patients showed normal DAT density in the striatum. Their clinical features included symmetric parkinsonism, early gait disturbances and postural instability, and the absence of resting tremor. The other two patients showed reduced striatal DAT uptake asymmetrically with a rostrocaudal gradient similar to idiopathic Parkinsons disease (IPD). They had clinical findings of hemiparkinsonism, resting tremor, without early gait disturbance or postural instability. They also showed sustained response to levodopa treatment. Based on the structured review of 21 cases with cirrhosis-related parkinsonism in the literature including the present cases, we categorized cirrhotic parkinsonism into three groups. Eleven of the twenty-one cases were categorized into group 1; levodopa-resistant atypical parkinsonism without a dopaminergic deficit in molecular imaging similar to primary manganism. Another 6 cases were categorized into group 2; coincidental IPD with superimposed cirrhosis with sustained good response to levodopa and presynaptic dopaminergic deficit with rostrocaudal gradient typical of IPD. The other undetermined 4 cases were categorized into group 3. They showed symmetric parkinsonism with variable response to levodopa therapy. Their molecular imaging showed a global diffuse dopaminergic deficit in the presynaptic molecular imaging distinct to group 1 (normal uptake) or 2 (asymmetric rostrocaudal deficit). In conclusion, cirrhosis-related parkinsonism is a heterogeneous disorder.

Angioimmunoblastic T-Cell Lymphoma in a Patient with Klinefelter Syndrome

Patient: Male, 61 Final Diagnosis: AITL in Klinefelter syndrome Symptoms: — Medication: — Clinical Procedure: Chemotherapy Specialty: Hematology Objective: Rare disease Background: Although patients with Klinefelter syndrome have elevated risk and incidence rates for several solid cancers, reports on the incidence of hematological malignancies have been equivocal. Case Report: We report a patient diagnosed with angioimmunoblastic T-cell lymphoma in whom Klinefelter syndrome was newly detected. Moreover, we discuss the development of a variety of lymphomas in patients with Klinefelter syndrome. Conclusions: This is the first case describing angioimmunoblastic T-cell lymphoma in a patient with Klinefelter syndrome who was treated with chemotherapy.

Diagnostic clue of nodular fasciitis mimicking metastasis in papillary thyroid cancer, mismatching findings on 18F-FDG PET/CT and 123I whole body scan: A case report

This study reports a case of nodular fasciitis incidentally detected in a patient with papillary thyroid cancer. A 47-year-old woman underwent a total thyroidectomy and radioactive iodine therapy for papillary thyroid cancer. On a follow-up fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) scan after 12 months, a focal 18F-FDG-avid lesion was incidentally detected in the paraspinal muscle. It was well-enhanced on CT and magnetic resonance imaging, indicating metastasis. However, the lesion was not iodine avid on the 123I whole body scan, which favored benign etiology over metastasis from thyroid cancer. For pathological confirmation, surgical excision was performed and the paraspinal lesion was finally confirmed as nodular fasciitis. Therefore, it was suggested that nodular fasciitis may be included in the differential diagnosis of a 18F-FDG avid/iodine non-avid soft tissue lesion in patients with thyroid cancer. In such circumstances, 123I whole body scans may serve a role in non-invasive work-up, and prevent unnecessary surgical procedures.

Mass-forming extramedullary hematopoiesis in multiple myeloma: 18F-FDG PET/CT is useful in excluding extramedullary myeloma involvement.

Aims and background Extramedullary hematopoiesis (EMH), a benign condition, is usually observed in patients with hematologic disorders. We report the first case of mass-forming EMH detected on a 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan in a patient with multiple myeloma (MM). Methods A 58-year-old woman underwent workup for bicytopenia, and was diagnosed with MM based on the results of bone marrow aspiration and serum protein electrophoresis. An 18F-FDG PET/CT scan revealed a paravertebral mass with mild FDG avidity, suggesting a tumorous condition. Results Biopsy was performed to exclude malignancy and the mass was eventually confirmed as EMH. Conclusions Differential diagnosis of a mildly FDG-avid paravertebral mass in MM should include EMH.

Follow-up bone scan in breast cancer patients: what is the appropriate interpretation of purely rib uptake?

AimAlthough rib uptake is frequently detected in follow-up bone scans of breast cancer patients, few studies have assessed its clinical significance. Patients and methodsAmong 1208 breast cancer patients who underwent a bone scan between 2011 and 2014, 157 patients presented with newly detected rib uptake at follow-up. Patients who had underlying bone metastases (n=8) or had simultaneous new uptake in sites other than the rib (n=13) were excluded. The patients enrolled finally were those who had purely rib uptakes. The location, intensity, and final diagnosis of the uptake were evaluated by nuclear medicine physicians. ResultsA total of 275 new instances of rib uptake were detected in follow-up bone scans of 136 patients. These were more frequently located on the ipsilateral side of the breast cancer (61.1%) and the anterior arc (65.1%), and they presented as moderate to intense (93.1%) uptakes. Among these, 265 lesions in 130 patients turned out to be benign fractures (96.4%), whereas only 10 lesions in six patients were metastases. The proportion of metastases was significantly higher if the uptake was linear or if the patient had recurrence. It was marginally higher if the uptake was located in the posterior arc. The proportion of metastases within the radiation field was significantly lower in patients with a history of irradiation. ConclusionNewly detected purely rib uptake on a follow-up bone scan in patients who have been treated for breast cancer is mostly because of fractures and rarely signals metastasis. However, if the patient has disease recurrence, metastasis should strongly be suspected, particularly when uptake is linear or located in the posterior arc.