Asia Oceania Journal of Nuclear Medicine and Biology最新文献

Rosai Dorfman disease is a rare form of nonlangerhans cell histiocytosis, presenting with extensive lymphadenopathies. Treatment in most cases of nodal disease, involves close observation; however, extranodal involvement requires a more definitive treatment strategy. Herein, we report a case of extensive Rosai Dorfman disease in a 43-year-old woman presenting for evaluation of treatment response by ¹⁸F-FDG PET/CT after frequent relapses and disease progression. In addition to extensive lymphadenothapies in cervical, supraclavicular, superior mediastinum, axillary, abdominopelvic and inguinofemoral regions, the patient had metabolically active bone and subcutaneous lesions which were not previously recognized. Following this ¹⁸F-FDG PET/CT study, the patient management was changed to sirolimus and prednisolone. To choose the best treatment option for Rosai Dorfman patients, knowledge of the full extent of disease is important. Compared with conventional imaging, ¹⁸F-FDG PET/CT has the advantage of being a whole-body imaging modality and can recognize disease involvement prior to any anatomical changes.

This quiz is part of a series which aims to aid nuclear physicians in interpreting the computed tomography (CT) component of the single photon emission computed tomography (SPECT) and positron emission tomography (PET) studies. The current quiz includes normal and pathological axial CT images at the level of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV). The SMV is normally located to the right of the SMA and is of a larger caliber. Various pathologies such as malignancy, infection or vascular disease can alter the position and/or appearance of the SMA, SMV and the surrounding anatomical structures present at this level. Understanding how normal anatomy is altered by pathology at this level will facilitate improved interpretation of abdominal CT images.

Objectives: Computed tomography (CT) images are used for precise anatomical location of lesions and for accurate attenuation correction in single-photon emission computed tomography (SPECT) image reconstruction in SPECT/CT examination. The aim of this study was to verify the effects of varying CT collimation width and slice thickness on CT images and on CT attenuation corrected SPECT images.

Methods: We acquired SPECT/CT images of a micro-coin phantom and the National Electrical Manufacturers Association body phantom filled with ^99mTc-pertechnetate while varying the abovementioned CT parameters. The full width at half maximum of the slice sensitivity profile, the standard deviation of CT image background noise, and the radiation dose from CT scans were evaluated. Subsequently, the percentage contrast, background variability, and absolute recovery coefficient of the SPECT image were measured. Furthermore, we retrospectively reviewed the clinical bone SPECT images of 23 patients, and statistical testing of differences was performed.

Results: As the collimation width and reconstruction slice thickness of the CT image increased, z-axis resolution deteriorated, and background noise decreased. In addition, CT radiation dose decreased with increasing collimation width. Meanwhile, SPECT image quality and quantitative accuracy were unchanged with varying CT collimation width and slice thickness. There were no notable variations in clinical SPECT images and no statistically significant differences.

Conclusion: When high-resolution CT slices on the z-axis are not required for clinical diagnosis, increasing collimation width or slice thickness can reduce the radiation dose and image noise with no influence on the quality of SPECT images .

Objectives: Combined positron emission tomography/computed tomography (PET/CT) has gradually advanced with the introduction of newly developed techniques. However, the recent status of imaging techniques (e.g., scanning range, availability of correction methods, and decisions on performing delayed scan) in oncologic PET/CT with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) in Japan is unclear. We conducted a nationwide cross-sectional survey to document ¹⁸F-FDG PET/CT protocols and clarify the recent status of imaging techniques for oncologic ¹⁸F-FDG PET/CT in Japan.

Methods: We conducted a web survey hosted by the Japanese Society of Radiological Technology between October and December 2017. The questionnaire included nine items on the demographics of the respondents, their scan protocols, and additional imaging to their routine protocols.

Results: We received responses from 119 Japanese technologists who performed ¹⁸F-FDG PET/CT in practice. Almost all the respondents stated that the scanning range was from the top of the head to the pelvis or mid-thigh region. Newly developed techniques were used by fewer than half of the respondents. Most respondents performed additional imaging in consultation with physicians, such as delayed imaging (83%) or an extended scanning range for early imaging (55%).

Conclusions: Our survey helps in clarifying the recent state of oncologic ¹⁸F-FDG PET/CT imaging techniques in Japan. Given that ¹⁸F-FDG PET/CT practices most frequently performed additional imaging along with their routine scan protocol, the practice constitutes the most varied examination performed in Japanese nuclear medicine.

Objectives: The purpose of this study was to investigate regional cerebral blood flow (rCBF) reduction in patients with dizziness and perfusion-related clinical impairment using brain perfusion single photon emission tomography (SPECT).

Methods: Thirty-four patients with subjective dizziness and 13 age- and sex-matched healthy controls were studied. Dizziness-related impairments were assessed using the Dizziness Handicap Inventory (DHI) and Short Physical Performance Battery (SPPB). Brain perfusion SPECT scan was acquired from all participants. The carotid intima-media thickness (CIMT) was also measured. Brain perfusion data were qualitatively interpreted in all cases. Voxel-wise analysis was also conducted in 11 patients compared to healthy controls.

Results: Thirty-four patients (mean age=53.8±13.4 years, m/f: 19/15) and 13 age- and sex-matched controls (mean age=51.5±13.1, m/f: 7/6) were included. The dizziness severity was mild in 58.8% (n=20), moderate in 26.5% (n=9), and severe in 14.7% (n=5). Qualitative interpretation of SPECT images showed normal scans in 4 (11.2%) patients and abnormal scans in 30 (88.2%) patients. Patients with dizziness showed a significantly decreased brain perfusion in the precuneus, cuneus, occipital lobe (superior and inferior parts), frontal lobe (inferior and middle parts), temporal lobe, parietal lobe (inferior and superior parts), cerebellum, insula, and putamen nucleus. Based on both qualitative SPECT interpretation and voxel-wise analysis, perfusion defect had a significant association with the total SPPB score and the scores of two sub-domains (p<0.05), but not with the DHI (p>0.05) score.

Conclusion: The perfusion- and atherosclerosis-related impairments of gait and balance were largely independent of subjective dizziness and dizziness severity. Moreover, this study provided support for contribution of perfusion impairment to the disturbance of gait and balance in older populations along with other pathologic processes.

Chordoma is a rare bone cancer which arises from undifferentiated notochordal remnants in the axial skeleton. It generally has slow-growing and locally aggressive behavior. This tumor is usually diagnosed by CT and MRI modalities and the role of SPECT/CT is still debated. It shows reduced or normal uptake of radioisotope on bone scanning and increased tracer uptake is infrequently reported. Here we present a 33-year-old man with complaint of low back pain and numbness of his right leg. The whole body bone scan showed relatively uniform radiotracer activity throughout the skeleton. A focal increased uptake in the second lumbar vertebra was noted on SPECT/CT images. SPECT/CT also demonstrated multiple lytic lesions in lumbar vertebrae. The lesions were proven to be chordoma on biopsy. Lumbar chordoma could be one of the differential diagnoses for lytic lesions of the vertebrae which show absent or minimal tracer uptake on bone scintigraphy and SPECT/CT imaging. Our case was unusual as the patient was very young for chordoma diagnosis and bone scan showed increased uptake adjacent to the involved vertebral lesion detected by SPECT/CT.

The role of fluorine-18-fluorodeoxyglucose positron emission tomography/ computed tomography (¹⁸F-FDG PET/CT) in patients with multiple myeloma (MM) and other plasma cell disorders is well-known. Solitary plasmacytoma (SP), an extremely rare form within this entity accounting for approximately 4% of plasma cell malignancies, can be classified as solitary bone plasmacytoma (SBP) or solitary extramedullary plasmacytoma (SEMP). Extramedullary plasmacytoma (EMP) is a rare neoplasm characterized by the monoclonal proliferation of plasma cells outside the bone marrow. Breast and craniocerebral regions are the uncommon sites of the presentations of EMP, rarely reported in the literature. The most frequent site of presentation is the upper airways. The EMPs have similar pathogenesis as MM; however, they differ in management as they are radiosensitive in nature, and radiotherapy is the preferred treatment modality. As SEMP has a better prognosis than SPB with a lower conversion rate to MM, accurate staging is essential to plan for the treatment. The ¹⁸F-FDG PET/CT has higher sensitivity for the evaluation of treatment response. In the present case series, it was aimed to depict the role of ¹⁸F-FDG PET/CT in newly diagnosed SEMP with different sites of origin to exclude further lesions leading to changes in the treatment plan and treatment response assessment.

Myocardial perfusion imaging is a non-invasive procedure that plays an integral role in the diagnosis and management of coronary artery disease. With the routine use of computerised tomography attenuation correction (CTAC) in myocardial perfusion imaging still under debate, the aim of this review was to determine the impact of CTAC on image quality in myocardial perfusion imaging. Medline, Embase and CINAHL were searched from the earliest available time until August 2019. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies version 2. Details pertaining to image quality and diagnostic accuracy were analysed, and results summarised descriptively. Three studies with 'unclear' risk of bias and low applicability concerns (1002 participants) from a yield of 2725 articles were identified. Two studies demonstrated an increase in image quality, and one study found no difference in image quality when using CTAC compared to no attenuation correction. Benefits of CTAC for improving image quality remain unclear. Given the potential exposure risk with the addition of CTAC, patient and clinician factors should inform decision making for use of CTAC in myocardial perfusion imaging for coronary artery disease.

The effectiveness of the sentinel lymph node mapping in patients with Urothelial carcinoma of the bladder is under investigation. Single photon emission computed tomography (SPECT/CT) and intraoperative sentinel node biopsy using gamma probe are performed to detect the exact location of the sentinel lymph node to be dissected during the surgery. In this case report, a 73-year old man with high grade urothelial carcinoma was referred to our nuclear medicine department for SPECT/CT, four hours after injection of the radiotracer through cystoscopy. SPECT/CT could not reveal any sentinel node; however, one sentinel lymph node was detected and harvested in the right external iliac region during surgery. SPECT/CT revealed unusual accumulation of tracer in large bowel which was due to severe adhesion of rectum and bladder, and inadvertent injection of the radiotracer into the rectal wall. During the sentinel lymph node procedure, the tracer should be injected with extreme caution and lymphoscintigraphy post injection may help detection of any injection failures.