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.

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.

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.

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.

Multiparametric analysis of preoperative lymphatic mapping with the use of combined deep plus superficial radiotracer injection technique in early breast cancer.

OBJECTIVES: According to literature, combined tracer injection techniques seem to be the more powerful choice to eliminate technical and patient-related limitations. In this study, we analysed the quantitative performance parameters of combined deep plus superficial radiotracer injection and their correlation with a set of clinical, pathological and technical factors. METHODS: One hundred and sixteen women who underwent preoperative sentinel lymph node (SLN) mapping were studied prospectively. All patients received the simultaneous deep and superficial injection of 99mTc-nanocolloid. Mapping success rate, mean number of SLNs per patient and radiotracer uptake of SLNs were determined. The possible effects of age, tumour stage, laterality and location, type and time of previous biopsy, and SLN status on the quantitative parameters were analysed. RESULTS: Axillary SLNs were visualized in all cases. Mean number of axillary SLNs was 2.15 and advanced age (>50) significantly decreased the number of SLNs. Radiotracer uptake of SLNs was also significantly decreased by advanced age and a shorter time interval between biopsy and mapping (<10 days). Extra-axillary SLN visualization rates for medial, lateral and periareolar injection sites were 32%, 16% and 8%. Although SLN gamma probe counts were significantly higher in the single-day protocol, the 2-day protocol gave better contrast values which was also an important parameter in lesion detection. CONCLUSION: The combined radiotracer injection technique successfully demonstrated axillary and extra-axillary SLNs. Advanced age and previous biopsy time can lower the accuracy and reliability of SLN biopsy. Although periareolar injection gave the best results for the axilla, it was still insensitive for extra-axillary SLNs in spite of deep injection.

QRS complex duration and dipyridamole gated SPECT findings in the left bundle branch block.

OBJECTIVE: The aim of this study was to investigate the relationship between QRS duration, artifactual perfusion abnormalities, and left ventricular function in patients with left bundle branch block (LBBB) using dipyridamole technetium-99m sestamibi electrocardiography-gated single-photon emission computed tomography (SPECT). METHODS: Twenty-three patients (62 +/- 12.2 years, 18 women, 5 men) with complete LBBB were analyzed. All patients underwent rest-dipyridamole gated SPECT (1-day protocol). To exclude patients with true myocardial ischemia and clearly define artifactual abnormalities owing to LBBB, only patients with normal end-diastolic stress images were involved. Four sets of SPECT images representing ungated rest, ungated stress, and end-diastolic and end-systolic stress images were generated, and the summed defect scores were obtained for each [summed rest score (SRS), summed stress score (SSS), end-diastolic score (EDS), and end-systolic score (ESS), respectively]. QRS durations were measured for both rest and dipyridamole stress. RESULTS: The patients with perfusion abnormalities on ungated rest, ungated stress, or end-systolic stress images had significantly longer minimum QRS duration at rest. These QRS values correlated with SRS and SSS (r: 0.528, P: 0.01 and r: 0.47, P: 0.024, respectively). Analysis of perfusion and functional data demonstrated an inverse correlation between left ventricular ejection fraction (LVEF) and ESS (r: -0.671, P < 0.0001). The patients with end-systolic perfusion abnormalities had significantly lower LVEF rates when compared with the patients with normal perfusion on end-systolic images. CONCLUSIONS: Our results demonstrated that the presence and severity of artifactual perfusion abnormalities owing to LBBB were significantly related to minimum QRS duration. The magnitude of perfusion abnormalities especially on the end-systolic phase seems to adversely affect systolic function of the left ventricle.

Renal cortical involvement in children with first UTI: does it differ in the presence of primary VUR?

OBJECTIVE: The aim of this study was to investigate the influence of vesicoureteral reflux (VUR) on dimercaptosuccinic acid (DMSA) scintigraphic patterns in children with first symptomatic urinary tract infection (UTI). METHODS: A total of 45 children with the diagnosis of first symptomatic UTI (28 girls, 17 boys, mean age 18 months, range 1 month-11 years) were reviewed. All DMSA scans were obtained within 2 months of bacteriologically proven UTI (median 21 days, mean 26 +/- 21, 14). After the exclusion of the patients with bilateral cortical lesions, 82 renal units were analyzed. The scintigraphic patterns included regional and global description of renal cortical abnormality (normal or decreased differential renal function, regional renal function (RRF), and the number and severity of cortical lesions). RESULTS: Vesicoureteral reflux was detected in 26 (32%) renal units (15 with grade 1-2, 11 with grade 3-4). Renal cortical abnormality was observed in 10 renal units without VUR (10/56, 17%) and 13 renal units with VUR (13/26: 50%). Of the 15 renal units, 5 with grade 1-2 VUR (5/15) and 8 of the 11 renal units with grade 3-4 VUR (8/11) had renal cortical involvement. The most common scintigraphic pattern in the patients without VUR was the preserved RRF (>or=45%) and two or fewer photon-deficient areas. On the other hand, a decreased RRF (<45) associated with cortical lesions was the most frequent finding in patients with refluxing kidneys (8/26, 30%), especially in those with grade 3-4 disease. CONCLUSIONS: This investigation showed that the presence of VUR affects DMSA patterns in children with first symptomatic UTI.

The clinical utility of 99mTc-HMPAO SPECT in Fahr's disease.

Fahr's disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99(m)Tc-D,L-hexamethylpropylene amine oxime (99(m)Tc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in a 42-year-old woman with Fahr's disease are reported, and the clinical utility of 99(m)Tc-HMPAO SPECT findings in Fahr's disease is discussed in this article. In conclusion, 99(m)Tc-HMPAO brain perfusion SPECT seems to be useful in the clinical approach to Fahr's disease, and may provide more specific and clinically relevant information when compared with anatomical imaging.

B-type natriuretic peptide levels in patients with COPD and normal right ventricular function.

INTRODUCTION: Evidence suggests that elevated plasma levels of B-type natriuretic peptide (BNP) are found in patients with chronic obstructive pulmonary disease (COPD) and right ventricular dysfunction. We examined the effects of exercise on plasma BNP levels in patients with COPD who have normal right ventricular function METHODS: Seventeen patients with a diagnosis of COPD and normal right ventricular function demonstrated by radionuclide ventriculography, and 17 age-and sex-matched healthy subjects underwent a treadmill exercise test. Plasma BNP levels were measured sequentially before, immediately after, and 1 hour after the exercise test RESULTS: The mean plasma BNP+/-standard deviation levels of the COPD and control groups before exercise were 21.3+/-16 pg/ml and 13.4+/-11 pg/ml, respectively (P>0.05). Mean plasma BNP level measured immediately after exercise was 37.9+/-31 pg/ml in the COPD group, reflecting a statistically significant increase when compared with the initial value (P<0.05). The control group did not show any significant change in plasma BNP levels after the exercise test CONCLUSIONS: Exercise induces an increase in plasma BNP levels in patients with COPD who do not have right ventricular dysfunction at rest. Measurement of exercise-induced BNP levels may be a useful alternative to pulmonary artery catheterisation in identifying the patients who are likely to benefit from long-term oxygen therapy.

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.

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.

Simple provocative maneuvers in renal transplant scintigraphy for detecting urine leak.

Urine leak in the early postoperative period following renal transplantation is a serious complication requiring early identification and aggressive intervention, which significantly reduces the morbidity and mortality. Renal transplant scintigraphy is a noninvasive method to evaluate the perfusion and function of a transplanted kidney and urinary drainage including urine leak. Here, we reported two cases in which the standard transplant renogram failed to demonstrate urine leak. The cases were referred for a diethylenetriaminepentaacetic acid renogram following the transplantation to evaluate the cause of symptoms or elevated serum creatinine level. In both the cases, urine leak was successfully detected following simple maneuvers such as diuretic administration or Foley catheter irrigation. Renal transplant scintigraphy is an effective and safe technique and the use of these simple maneuvers can enhance the diagnostic sensitivity of the transplant renogram in the detection of urine leak.

Assessment of right and left ventricular perfusion in patients with right bundle branch block.

BACKGROUND: Patients with conduction abnormalities may have abnormal images on perfusion scintigraphy without evidence of coronary artery disease (CAD). Based on the presence of left ventricular perfusion abnormalities in left bundle branch block and taking advantage of the Tc-99m sestamibi for the assessment of myocardial perfusion of both ventricles, we aimed to evaluate right (RV) and left (LV) myocardial perfusion in patients with right bundle branch block (RBBB). METHODS: This study included 21 patients with RBBB and 21 control subjects without conduction abnormality. None had previous myocardial infarction, known CAD, left ventricular hypertrophy, LVEF <55%, congenital, pulmonary or valvular heart disease. Rest and stress SPECT images were obtained using 1-d Tc-99m sestamibi SPECT protocol. Regional perfusion of LV and RV myocardium was semiquantitatively evaluated. Also, RV/LV uptake ratio was calculated in two different ways. RESULTS: In patients with RBBB, the normality ratios of RV and LV myocardial perfusion were very high (both 90.5%) and not different from those of patients with normal intraventricular conduction. In the comparison of RV/LV uptake ratios, no significant difference was found between the RBBB and control groups. CONCLUSIONS: LV perfusion, RV perfusion or R-to-L perfusion ratio were not significantly influenced by the conduction abnormality in this selected patient population with RBBB. Tc-99m sestamibi myocardial scintigraphy could help in the exclusion of myocardial ischemia in patients with RBBB.

Reproducibility of technetium-99m mercaptoacetyltriglycine clearance in patients with impaired renal function.

BACKGROUND: The aim of this study was to determine the reproducibility of technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) clearance in patients with a 99mTc-MAG3 clearance below 100 ml/min/1.73 m2. METHODS: Two separate multi-sample clearance studies were performed in 16 patients at a 1 week interval. The clearances were calculated according to the open two-compartment model of Sapirstein et al., accepting the 90, 120 and 180 min samples as the last points of the biexponential curve. The clearance measurements were also performed according to the single-sample methods of Russell et al. and Bubeck using the fitted value at 44 min. RESULTS: There was no significant difference between the two clearance measurements for all five samples (P>0.05). There was a systematic increase in clearance measurements of 8.0+/-2.7% from the 180 to 120 min samples and 4.8+/-2.0% from the 120 to 90 min samples. Both single-sample methods (Bubeck and Russell et al.) gave more divergent results than multi-sample methods. The mean and standard deviation (%) of the normalized differences between two successive tests were -3.9+/-12.6, -2.4+/-13.1, -1.9+/-14.9, -4.1+/-53.5 and -13+/-82.1 for 90, 120 and 180 min samples and the Russell et al. and Bubeck methods, respectively. CONCLUSION: Single-sample methods give very poor reproducibility and accuracy and should not be used in patients with poor renal function. The reproducibility of 99mTc-MAG3 clearance using the multi-sample method (90 min) in patients with impaired renal function is 12.6%, which is similar to that in patients with good renal function and that obtained with other tubular agents. Whether this level of reproducibility is satisfactory for documenting serial changes in an individual patient with a 99mTc-MAG3 clearance below 100 ml/min/1.73 m2 depends on the expectation of the clinician.

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.