The Role of a Bone SPECT/CT Scan in the Follow-up of a Solitary Bone Lesion in a Patient with Langerhans' Cell Histiocytosis

Langerhans' cell histiocytosis (LCH) is a rare disease observed in childhood characterized by the proliferation of Langerhans' cells resulting in focal or systemic manifestations (including the bones). Here, we present a pediatric case with a localized biopsy-proven LCH, who underwent progression from solitary to multifocal form detected on bone scintigraphy and single photon emission computerized tomography/computed tomography (SPECT/CT) performed within four months. Emphasizing on localized bone pain (predictive of osseous LCH) and local tenderness and swelling usually guides the nuclear physician to perform additional SPECT/CT with presumably an improvement of the diagnostic accuracy as demonstrated in our case.

Correlation Between Perfusion Abnormalities Extent in Ventilation/Perfusion SPECT/CT with Hemodynamic Parameters in Patients with Chronic Thromboembolic Pulmonary Hypertension

Objectives: Chronic thromboembolic pulmonary hypertension (CTEPH) is a type of pulmonary hypertension with persistent pulmonary vascular obstruction and exercise intolerance, which may benefit from pulmonary endarterectomy (PEA). Ventilation/perfusion (V/Q) scan is the preferred screening test of CTEPH, which can be used to assess the anatomical extent of the disease. This study aimed to analyze the correlation between the extent of mismatched Q defects in V/Q single photon emission computed tomography/computed tomography (SPECT/CT) with preoperative clinical and hemodynamic parameters in patients with CTEPH. Methods: A total of 102 patients with CTEPH prior to PEA having V/Q SPECT/CT scans were retrospectively reviewed. Age, gender, New York Heart Association classification, intraoperative right-sided heart catheterization (mPAP and PVR), and 6-minute walk test (6MWT) findings were obtained from clinical records of patients. Results: Linear regression analysis showed a significant but weak correlation between the preoperative mPAP and PVR with the extent of mismatched Q defects in V/Q SPECT/CT (rs=0.09474 with p=0.0016 and rs=0.045 with p=0.045, respectively). No significant correlation was found between 6MWT and extent of mismatched Q defects in V/Q SPECT/CT (p>0.05). Conclusion: A quantitative assessment of Q defects on V/Q SPECT/CT might provide information about hemodynamic parameters in patients with CTEPH.

Physiological Biodistribution of 68Ga-DOTA-TATE in Normal Subjects

Objectives: Somatostatin is an endocrine peptide hormone that regulates neurotransmission and cell proliferation by interacting with G protein-coupled somatostatin receptors (SSTRs). SSTRs are specific molecular targets of several radiotracers for neuroendocrine tumor (NET) imaging. Gallium-68 (68Ga)-DOTA-TATE is widely used for positron emission tomography/computed tomography (PET/CT) imaging of SSTRs and has shown a higher affinity for SSTR2, the most common SSTR subtype found in NETs. We aimed to analyze the distribution pattern of 68Ga-DOTA-TATE in normal subjects. Methods: A total of 617 consecutive 68Ga-DOTA-TATE PET/CT whole-body scans performed in our department from May 2015 through April 2020 with known or suspected neuroendocrine malignancies, mostly to evaluate adrenal adenomas, were retrospectively analyzed by 2 nuclear medicine physicians. One hundred eighteen subjects without a diagnosis of NET, with no tracer avid lesion of NET on 68Ga-DOTA-TATE PET/CT, and followed up for at least 6 months (average 2-3 years) without any biochemical, clinical, or imaging findings suggestive of NET were included in this study. Results: The highest uptake of 68Ga-DOTA-TATE was noted in the spleen followed by the kidneys, adrenal glands, liver, stomach, small intestine, prostate gland, pancreas head, pancreas body, thyroid gland, and uterus, in descending order. Minimal to mild uptake was detected in the submandibular glands, parotid glands, thymus, muscles, bones, breast, lungs, and mediastinum. Conclusion: Our study shows the biodistribution pattern of 68Ga-DOTA-TATE in normal subjects and the ranges of the maximum standard uptake value (SUVmax) and SUVmean values of 68Ga-DOTA-TATE obtained in several tissues for reliably identifying malignancy in 68Ga-DOTA-TATE PET/CT studies.

Chronic thromboembolic pulmonary hypertension: evaluation of V/Q SPECT/CT and V/Q Quotient SPECT findings with postoperative results of pulmonary endarterectomy.

OBJECTIVES: We aimed to perform a comparison between V/Q single-photon emission computed tomography/computed tomography (SPECT/CT) and V/Q Quotient single-photon emission computerized tomography (SPECT) in the detection of chronic thromboembolic pulmonary hypertension (CTEPH) and in depicting the extent of the disease on per-segment basis in patients with CTEPH. METHODS: Between January 2015 and November 2019, a total of 412 patients with pulmonary hypertension secondary to CTEPH at the preoperative assessment underwent pulmonary endarterectomy (PEA), of whom 92 consecutive patients with their V/Q SPECT/CT scans have been performed in our institution prior to PEA were included in this study. Histopathological findings and post-PEA fully resected surgical specimens were used as the reference standard. RESULTS: On a per-patient basis analysis, V/Q SPECT/CT and V/Q Quotient SPECT both revealed CTEPH in the same 85 of the 92 patients (κ = 1) with a detection rate of 92.4%. In six of these patients, chronic thromboembolic disease could not be reported on both of these two methods due to extensive 'matched' V/Q defects. On a per-segment basis analysis, V/Q SPECT/CT and V/Q Quotient SPECT showed a sensitivity of 75.8 and 73.1%, respectively. Correlation analysis results showed a significant correlation (κ = 0.933) between these two methods on a per-segment basis analysis. CONCLUSION: In the light of histopathological findings and post-PEA surgical specimen examinations, the results of the present study indicated that both V/Q SPECT/CT and V/Q Quotient SPECT showed relatively high efficacy for the detection of CTEPH on per-patient and per-segment bases with an excellent agreement.

Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging in Pseudo Sister Mary Joseph's Nodule.

Sister Mary Joseph's nodule (SMJN) refers to umbilical metastatic lesions and indicates widespread intra-abdominal malignancy. The most common primary sites are gastrointestinal and genital tract. Benign umbilical nodules are called pseudo-SMJN (PSMJN) and have been also reported in nonmalignant lesions such as endometriosis, fibroma, papillomas, myxoma, keloid, omphalith, nevi, foreign-body granulomas, and epidermoid cysts. We report a case with PSMJN as an extremely rare manifestation of intra-abdominal tuberculosis.

99m-Technetium-Labeled Red Blood Cells' Single-Photon Emission Computed Tomography/Computed Tomography in Situs Ambiguous with Polysplenia.

Situs ambiguous or heterotaxy syndrome is defined as the abnormal arrangement of organs and vessels within the body. Herein, we present an 8-year-old girl with growing right-sided suprarenal masses mimicking adrenal tumors. Technetium-99-m-radiolabeled red blood cells' planar images were inconclusive for the diagnosis of splenic tissue in the right side. Single-photon emission computed tomography/computed tomography imaging clearly identified right-sided functioning spleens and confirmed the diagnosis of situs ambiguous with polysplenia.

68Ga-PSMA PET/CT in Giant Retroperitoneal Liposarcoma.

Primary retroperitoneal liposarcoma is an extremely rare malignant tumor. Herein, we report a case with an incidentally detected giant retroperitoneal liposarcoma on Ga-PSMA PET/CT during primary staging for prostate cancer.

Change in standardized uptake values in delayed 18F-FDG positron emission tomography images in hepatocellular carcinoma.

Delayed 18F-2-fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography (PET) imaging has been associated with improved diagnostic yield in several malignancies; however, data on the use of delayed imaging in patients with hepatocellular carcinoma (HCC) is scarce. This study aimed to examine tumoral and background standardized uptake value (SUV) alterations in dual-phase F-FDG PET/computed tomography (CT) imaging.Fifty-two HCC cases underwent dual-time-point F-FDG PET/CT examination where early and delayed images were obtained. The maximum and mean SUVs (SUVmax and SUVmean) of the tumor were determined for both time points. Similarly, the average SUVmean were also determined for background (liver, soft tissue, and spleen). Changes in tumoral and background SUV between early and delayed images were examined.The mean age was 62.0 ±â€Š12.9 years (range, 20-88 years) and the majority of the patients were men (86.5%). Tumor SUVs, both tumor SUVmean and tumor SUVmax, significantly increased at delayed images when compared to early images. In contrast, the average SUVmean for the liver, soft tissue, and spleen significantly decreased at delayed images.A significant increase in tumor SUV in delayed images in contrast to a significant decrease in background SUVs suggests that delayed images in HCC may contribute to diagnostic performance through a potential increase in the contrast between the tumor and background. However, further studies with larger sample sizes including patients with benign lesions and different grades of the disease are warranted to better elucidate the diagnostic contribution as well as the association of delayed imaging values with prognosis.

Positional installation of contrast (PIC) and Redo-PIC cystography for diagnosis of occult vesicoureteral reflux.

Karadeniz-Cerit K, Thomas DT, Ergun R, Yildiz N, Alpay H, Inanir S, Dagli ET, Tugtepe H. Positional installation of contrast (PIC) and Redo-PIC cystography for diagnosis of occult vesicoureteral reflux. Turk J Pediatr 2018; 60: 180-187. To evaluate the value of Positional Installation of Contrast (PIC) and Redo-PIC cystography in patients with febrile recurrent urinary tract infection (f-UTI) where voiding cystourethrogram (VCUG) was negative. Patients with recurrent f-UTI with no reflux on VCUG referred to the outpatient clinic of Pediatric Urology, between June 2011 and June 2016 were included in the study. A PIC cystography was performed in all patients. When reflux was found, subureteric injection was performed. Urinary cultures were used for follow-up. Patients that continued having f-UTI, received redo-PIC cystography. PIC cystography was performed on 42 patients. The average age of patients was 8.0±3.6 years. Vesicoureteral reflux (VUR) was detected in 41 patients. Average follow-up time after PIC cystography was 44.6 months. Thirty-three patients (80.5%) were free of f-UTI after PIC cystography and concurrent subureteric injection. Eight patients continued to have recurrent f-UTI. Six of these patients underwent redo-PIC cystography and PIC-VUR was demonstrated in all patients. After an average follow up of 30.9 months, no f-UTI was seen in these patients. The success rate of 80.5% (33/41) after 1st PIC cystography and subureteric injection increased to 95.1% (39/41) after redo-PIC cystography in six patients. Patients with recurrent f-UTIs without VUR on VCUG are an important challenge. PIC cystography is an important tool in demonstrating occult VUR in these patients. We advise that PIC cystography is performed in all patients with recurrent f-UTI with negative VCUG and redo-PIC cystography in patients who continue to have f-UTI after 1st PIC cystography and subureteric injection.

2-(fluorine-18)-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography after breast conserving surgery: Correlation with molecular markers of breast cancer.

AIM: To investigate the role of 2-(fluorine-18)-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) early after breast-conserving surgery (BCS) in patients with breast cancer (BC) and whether we can determine which molecular biomarkers of breast carcinoma put the patients at risk. MATERIALS AND METHODS: This retrospective study involved 88 patients with histologically proven T1 or T2 BC, who were treated with BCS and underwent (18)F-FDG PET/CT study. The correlation between biological markers (estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 [HER2], and Ki-67) of the primary tumor and (18)F-FDG PET/CT findings was analyzed. RESULTS: (18)F-FDG PET/CT demonstrated the presence of BC disease (locoregional disease [LRD], distant metastases, or contralateral BC) in 26 of 88 patients (29.5%). Regarding immunohistochemical profiles, BC expressing high levels of Ki-67 were associated with an increased percentage of LRD, which was the major recurrence pattern on (18)F-FDG PET/CT. Although the BC disease was observed more commonly in patients with HER2 positivity compared to those of HER2 negative, the difference did not reach statistical significance. The patients with T2 tumor or a higher histopathological grade had a higher percentage of BC disease. CONCLUSIONS: This study demonstrated that patients with early stage BC treated with BCS have a remarkable risk of the presence of BC even early after surgery, and there was a clinically important relationship between (18)F-FDG PET/CT findings and biological markers of BC. These findings suggest that high-risk molecular biomarkers (Ki-67, HER2) can be taken into account in the decision-making the process for both preoperative imaging and planning of the surgical approach.

FDG PET/CT Imaging of Calcified Sister Mary Joseph Nodule.

Sister Mary Joseph nodule (SMJN) refers to any metastatic deposit in the periumbilical region. Herein, we report a very rare case of calcified SMJN from ovarian papillary serous adenocarcinoma showing intense FDG uptake.

Comparison of WHO, RECIST 1.1, EORTC, and PERCIST criteria in the evaluation of treatment response in malignant solid tumors.

AIM: To compare response assessment according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria in patients diagnosed with malignant solid tumors and who had received cytotoxic chemotherapy to establish the strength of agreement between each criterion. MATERIALS AND METHODS: Sixty patients with malignant solid tumors were included in this retrospective study. The baseline and the sequential follow-up fluorine-18-fluorodeoxyglucose PET/computed tomography (CT) of each patient were evaluated according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria. PET/CT images were used for both metabolic and anatomic evaluation. The concurrent diagnostic CT and MRI images (performed within 1 week of PET/CT) were also utilized when needed. The results were compared using the κ-statistics. RESULTS: The response and progression rates according to the WHO criteria were 37 and 38%, respectively. The same ratios were also found for RECIST 1.1 (κ=1). The response and progression rates according to the EORTC criteria were 47 and 40%, respectively. When PERCIST criteria were used, one patient with progressive disease was upgraded to stable disease (κ=0.976). As we found the same results with WHO and RECIST 1.1 criteria, we used WHO criteria to compare the anatomic and metabolic criteria. When we compared the WHO and EORTC criteria, there was an agreement in 80% of the patients (κ=0.711). With WHO and PERCIST criteria, there was an agreement in 81.6% of the patients (κ=0.736). CONCLUSION: Significant agreement was detected when the WHO, RECIST 1.1, EORTC, and PERCIST criteria were compared both within as well as between each other.

A rare case mimicking positron emission tomography/computed tomography mismatch: Hepatic subcapsular hematoma.

Subcapsular collections of bile, air or blood in the liver have been described following transhepatic procedures due to the leakage of bile and blood from the percutaneous puncture at the surface of the liver. Herein we presented the subcapsular collection led to a mismatch between functional and anatomical boundaries of the liver.

Flip-flop phenomenon in systemic sclerosis on fluorodeoxyglucose positron emission tomography/computed tomography.

Systemic sclerosis (SSc) is a rare autoimmune disease, which may affect multiple organ systems. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can demonstrate the degree and anatomical extent of involvement in the entire body and coexisting malignancies in connective tissue diseases. We present a case of SSc with an increased 18F-FDG uptake in the cutaneous and subcutaneous tissues even higher than the neighboring skeletal muscles ("flip-flop phenomenon," that is, an increased 18F-FDG uptake in the skin but a decreased 18F-FDG uptake in the skeletal muscles).

Carbon-14 urea breath test: does it work in patients with partial gastric resection?

OBJECTIVE: The diagnostic value of Carbon-14 urea breath test (C-14 UBT) in the detection of Helicobacter pylori (H. pylori) infection in non-operated patients has been proved. However, the efficacy of C-14 UBT in patients with partial gastric resection (PGR) has not been evaluated yet. Herein, the results of the C-14 UBT and H. pylori stool antigen test (HpSAT) in this patient group were compared with the endoscopic findings. METHODS: Multi-breath samples C-14 UBT and HpSAT were performed in all patients on the same day. Histology was used as a gold standard for testing C-14 UBT and HpSAT diagnostic efficacies. RESULTS: 30 patients (mean age: 54.6 ± 11 year) with PGR were included. The sensitivity and specificity of standard C-14 UBT were 29 and 100 %, respectively. When breath samples were collected at 20th min, and >35 CPM was selected as radioactivity threshold, the sensitivity raised to 86 % without any loss of specificity. The specificity and sensitivity of the HpSAT were 71 and 96 %, respectively. CONCLUSIONS: The sensitivity of the standard C-14 UBT was very poor for patients with PGR, and results of HpSAT were superior in this population. Certain modifications are needed if C-14 UBT is to be used in PGR patients.

Mesenteric metastases of purely myxoid liposarcoma: An unusual behavior of primary tumor depicted on fludeoxyglucose positron emission tomography/computerized tomography.

A 48-year-old male patient with purely myxoid liposarcoma was referred to fludeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) for restaging. FDG PET/CT images showed a hypodense well-defined intermuscular mass with mild FDG uptake in the right gluteal region. In addition, multiple mild hypermetabolic masses that had similar characteristics with the aforementioned lesion were also revealed in the mesenteric region of abdomen and pelvis.