The significance of bremsstrahlung SPECT/CT after yttrium-90 radioembolization treatment in the prediction of extrahepatic side effects

Purpose  

Unwanted deposition of ⁹⁰Y microspheres in organs other than the liver during radioembolization of liver tumours may cause severe side effects such as duodenal ulcer. The aim of this study was to evaluate the significance of posttherapy bremsstrahlung (BS) SPECT/CT images of the liver in comparison to planar and SPECT images in the prediction of radioembolization-induced extrahepatic side effects.     

Usefulness of 67Ga SPECT and integrated low-dose CT scanning (SPECT/CT) in the diagnosis of cardiac sarcoidosis

Objective We performed ⁶⁷Gallium (Ga) single-photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT) for the interpretation of myocardial outline to investigate the value of co-registered fusion imaging using a hybrid system (SPECT/CT) in patients with cardiac sarcoidosis. Methods SPECT/CT of the region in question was performed with VG Hawkeye. The subjects in this study were 37 patients [mean (±SD) age 61.0 ± 13.0 years; 12 men and 25 women], 13 of whom had a clinical diagnosis of cardiac sarcoidosis and 24 a negative diagnosis. An intravenous injection of Ga (dosage 111 MBq) was performed on patients 48 h or 72 h before obtaining static planar images of the whole-body and the SPECT/CT scan. Results Abnormal Ga uptake in the myocardium was observed in 10 of the 13 subjects with true sarcoidosis, and in 11 of 24 with negative sarcoidosis without CT fusion. The sensitivity without CT fusion was 77%, the specificity 54%, and the accuracy 62%. Use of SPECT/CT changed the diagnosis only in a patient with true sarcoidosis, and changed the diagnosis in eight patients with negative sarcoidosis. The sensitivity with CT fusion was 69%, the specificity 79%, and the accuracy 76%. The difference in diagnostic accuracy was statistically significant (McNemar's test, P = 0.039). Conclusions SPECT scanning using Ga and integrated low-dose CT is a very useful diagnostic imaging technique because it improves the diagnostic specificity of Ga SPECT to allow the highly specific diagnosis of cardiac sarcoidosis.     

Usefulness of Additional SPECT/CT Identifying Lymphatico-renal Shunt in a Patient with Chyluria

Lymphoscintigraphy is known to be a useful and non-invasive modality for the evaluation of lymphatic abnormality. However, lymphoscintigraphy has limitations in evaluating chyluria because of its lack of anatomical information. Additional single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was considered to be potentially helpful in detecting the abnormal lymphatico-renal communication. A 20-year-old male patient was referred to our hospital for evaluation of recurrent chyluria. During the third recurrence of chyluria, additional SPECT/CT along with lymphoscintigraphy was performed for evaluation. From the combined SPECT/CT images, lymphatic drainage of radiotracers to the kidney was well visualized, helping diagnosis of a patient with chyluria.     

Usefulness of hybrid SPECT/CT in 99mTc-HMPAO-labeled leukocyte scintigraphy for bone and joint infections.

White blood cell scanning with (99m)Tc-hexamethylpropylene amine oxime (HMPAO) has proven highly sensitive and specific in the diagnosis and follow-up of patients with suspected osteomyelitis. The aim of this prospective study was to evaluate the usefulness of SPECT and transmission CT performed simultaneously using a hybrid imaging device for the functional anatomic mapping of bone and joint infections. METHODS: (99m)Tc-HMPAO scintigraphy was performed on 28 consecutive patients: 15 with suspected bone infection (group 1) and 13 with suspected orthopedic implant infection (group 2). Planar scans were acquired 30 min, 4 h, and 24 h after injection. SPECT/CT was obtained 6 h after tracer injection, using a dual-head gamma-camera coupled with a low-power x-ray tube. In all patients, scintigraphic results were matched with the results of surgery or cultures and of clinical follow-up. RESULTS: (99m)Tc-HMPAO scintigraphy was true-positive for infection in 18 of 28 patients (for a total of 21 sites of uptake) and true-negative in 10 of 28 subjects. SPECT/CT provided an accurate anatomic localization of all positive foci. With regard to the final diagnosis, SPECT/CT added a significant clinical contribution in 10 of 28 patients (35.7%). In fact, SPECT/CT differentiated soft-tissue from bone involvement both in patients with osteomyelitis and in patients with orthopedic implants, allowed correct diagnosis of osteomyelitis in patients with structural alterations after trauma, and identified synovial infection without prosthesis involvement in patients with a knee implant. CONCLUSION: Our results indicate that SPECT/CT performed using a hybrid device can improve imaging with (99m)Tc-HMPAO-labeled leukocytes in patients with suspected osteomyelitis by providing accurate anatomic localization and precise definition of the extent of infection.     

Automated segmentation and detection of increased uptake regions in bone scintigraphy using SPECT/CT images

Purpose

To develop a method for automated detection of highly integrated sites in SPECT images using bone information obtained from CT images in bone scintigraphy.

Methods

Bone regions on CT images were first extracted, and bones were identified by segmenting multiple regions. Next, regions corresponding to the bone regions on SPECT images were extracted based on the bone regions on CT images. Subsequently, increased uptake regions were extracted from the SPECT image using thresholding and three-dimensional labeling. Last, the ratio of increased uptake regions to all bone regions was calculated and expressed as a quantitative index. To verify the efficacy of this method, a basic assessment was performed using phantom and clinical data.

Results

The results of this analytical method using phantoms created by changing the radioactive concentrations indicated that regions of increased uptake were detected regardless of the radioactive concentration. Assessments using clinical data indicated that detection sensitivity for increased uptake regions was 71% and that the correlation between manual measurements and automated measurements was significant (correlation coefficient 0.868).

Conclusion

These results suggested that automated detection of increased uptake regions on SPECT images using bone information obtained from CT images would be possible.

     

Comparative dosimetry between 99mTc-MAA SPECT/CT and 90Y PET/CT in primary and metastatic liver tumors

European Journal of Nuclear Medicine and Molecular Imaging - The aim of this study is to determine whether 99mTc-MAA SPECT/CT-based dosimetry could predict the actual absorbed dose in...     

Assessment of inflammatory jaw pathologies using bone SPECT/CT maximum standardized uptake value

Objectives:To investigate the assessment of inflammatory jaw pathologies using bone single-photon emission CT-CT (SPECT/CT) maximum standardized uptake value (SUV_max).Methods:44 patients with inflammatory jaw pathologies (7 chronic osteomyelitis, 8 osteoradionecrosis and 29 medication-related osteonecrosis of the jaw (MRONJ)) underwent SPECT/CT at 4 h after injection of ^99mTc hydroxymethylene diphosphonate. The SPECT/CT parameters SUV_max of the inflammatory jaw pathologies were analyzed. Statistical analyses for the SUV_max were performed by one-way repeated measures analysis of variance with Tukey''s honestly significant difference test. A p-value lower than 0.05 was considered statistically significant.Results:The mean and standard deviation of SUV_max for 7 chronic osteomyelitis, 8 osteoradionecrosis and 29 MRONJ were 24.94 ± 3.65, 12.27 ± 5.47 and 16.55 ± 9.12, respectively. The SUV_max for chronic osteomyelitis were significantly higher than those for osteoradionecrosis (p = 0.011) and MRONJ (p = 0.043).Conclusions:Bone SPECT/CT SUV_max in the uptake of ^99mTc hydroxymethylene diphosphonate reflecting bone physiological changes for chronic osteomyelitis were significantly higher than those of osteonecrosis, such as osteoradionecrosis and MRONJ. Bone SPECT/CT SUV_max should be useful for the assessment of inflammatory jaw pathologies, such as chronic osteomyelitis, osteoradionecrosis and MRONJ.     

Small-animal SPECT and SPECT/CT: application in cardiovascular research

Preclinical cardiovascular research using noninvasive radionuclide and hybrid imaging systems has been extensively developed in recent years. Single photon emission computed tomography (SPECT) is based on the molecular tracer principle and is an established tool in noninvasive imaging. SPECT uses gamma cameras and collimators to form projection data that are used to estimate (dynamic) 3-D tracer distributions in vivo. Recent developments in multipinhole collimation and advanced image reconstruction have led to sub-millimetre and sub-half-millimetre resolution SPECT in rats and mice, respectively. In this article we review applications of microSPECT in cardiovascular research in which information about the function and pathology of the myocardium, vessels and neurons is obtained. We give examples on how diagnostic tracers, new therapeutic interventions, pre- and postcardiovascular event prognosis, and functional and pathophysiological heart conditions can be explored by microSPECT, using small-animal models of cardiovascular disease.     

Usefulness of Tc-99m Pertechnetate SPECT/CT in the Diagnosis of Testicular Infarction After Inguinal Herniorrhaphy

A 77-year-old male underwent open repair for a right indirect inguinal hernia and complained of right scrotal pain on the third postoperative day. Color Doppler imaging revealed decreased blood flow with heterogeneous hypoechogenicity in the right testis. A Tc-99m pertechnetate testicular scan showed diffuse hyperemia and increased uptake in the right scrotum. Additional SPECT/CT revealed a photon defect in the right testicle with increased uptake in the peri-testicular area. A subsequent operation revealed a large hematoma in the right spermatic cord and consequent right testicular infarction, and right orchiectomy was performed.     

Sources of attenuation-correction artefacts in cardiac PET/CT and SPECT/CT

PURPOSE: Respiratory motion during myocardial perfusion imaging can cause artefacts in both positron emission tomography (PET) and single-photon emission computed tomography (SPECT) images when mismatches between emission and transmission datasets arise. In this study, artefacts from different breathing motions were quantified in both modalities to assess key factors in attenuation-correction accuracy. METHODS: Activity maps were generated using the NURBS-based cardiac-torso phantom for different respiratory cycles, which were projected, attenuation-corrected and reconstructed to form PET and SPECT images. Attenuation-correction was performed with maps at mismatched respiratory phases to observe the effect on the left-ventricular myocardium. Myocardial non-uniformity was assessed in terms of the standard deviation in scores obtained from the 17-segment model and changes in uniformity were compared for each mismatch and modality. RESULTS: Certain types of mismatch led to artefacts and corresponding increases in the myocardial non-uniformity. For each mismatch in PET, the increases in non-uniformity relative to an artefact-free image were as follows: (a) cardiac translation mismatch, 84% +/- 11%; (b) liver mismatch, 59% +/- 10%, (c) lung mismatch from diaphragm contraction, 28% +/- 8%; and (d) lung mismatch from chest-wall motion, 6% +/- 7%. The corresponding factors for SPECT were (a) 61% +/- 8%, (b) 34% +/- 8%, (c) -2% +/- 7)% and (d) -4% +/- 6%. CONCLUSIONS: Attenuation-correction artefacts were seen in PET and SPECT images, with PET being more severely affected. The most severe artefacts were produced from mismatches in cardiac and liver position, whereas lung mismatches were less critical. Both cardiac and liver positions must, therefore, be correctly matched during attenuation correction.     

Distribution of the extrahepatic uptake in liver diseases as recorded by scintigraphy

Liver scintigraphy performed with 99Tcm-S and Sn colloid ought to be named RES scintigraphy as the distribution of the colloid is mainly determined by the phagocytic capacity of the RES but also by the regional blood flow and the features of the colloid. Both diffuse hepatocellular disease and malignant disease may have decreased activity in the liver and increased extrahepatic activity: spleen, bone marrow and lungs. In liver cirrhosis at least 3 types of distribution of activity can be recognized: (a) equal increase in spleen, bone marrow and lungs, (b) mainly increase in spleen, and (c) mainly increase in bone marrow and lungs. Therefore a ratio between the total extrahepatic and the hepatic activity ought to be calculated rather than a spleen/liver ratio.     

Methylene diphosphonate uptake in a case of vertebral hemangioma: demonstration with hybrid SPECT/CT

Osseous hemangiomas are usually asymptomatic. Symptomatic hemangiomas are rare and represent approximately 1% of all cases. Hemangiomas usually present as photopenic defects in methylene diphosphonate (MDP) bone scintigraphy. MDP uptake in vertebral hemangiomas is extremely rare. We report a 20-year-old woman who presented with upper back pain. MDP bone scan showed focus of MDP uptake in the seventh dorsal vertebra. SPECT/CT localized the uptake to vertebral body and transverse process with CT findings suggestive of hemangioma. Further, MRI also confirmed hemangioma in the same location.     

肝硬化肝内外门-体循环交通的CT表现

目的探讨肝硬化门静脉高压肝内外门-体循环交通的发生率及CT表现特点。方法回顾性分析80例肝硬化门脉高压患者的肝内外门-体交通的螺旋CT三期扫描表现。结果肝外型门-体循环交通见于79例（98．75％），其中，食管下段黏膜下及食管周围静脉曲张48例（60％），奇静脉和半奇静脉扩张28例（35％），小网膜静脉曲张46例（57．5％），副脐静脉肝外型再通20例（25％），脾肾静脉和胃肾静脉分流10例（12．5％），腹膜后椎旁静脉曲张14例（17．5％）；肝内型门-体循环交通6例（7．5％），其中，5例为门静脉左支与副脐静脉交通型（6．25％），1例为门静脉右后支与下腔静脉交通型（1．13％）。结论螺旋CT三期扫描对肝硬化门静脉高压侧支循环的显示有独特的价值，不仅能显示侧支循环的部位、范围和曲张的程度，而且可以追踪血流异常途径。认识侧支循环的CT表现特点，有助于肝内外疾病的鉴别诊断。