Studies have shown that the conventional parameters characterizing left ventricular mechanical dyssynchrony (LVMD) measured on gated SPECT myocardial perfusion imaging (MPI) have their own statistical limitations in predicting cardiac resynchronization therapy (CRT) response. The purpose of this study is to discover new predictors from the polarmaps of LVMD by deep learning to help select heart failure patients with a high likelihood of response to CRT.

One hundred and fifty-seven patients who underwent rest gated SPECT MPI were enrolled in this study. CRT response was defined as an increase in left ventricular ejection fraction (LVEF) > 5% at 6 [Formula: see text] 1 month follow up. The autoencoder (AE) technique, an unsupervised deep learning method, was applied to the polarmaps of LVMD to extract new predictors characterizing LVMD. Pearson correlation analysis was used to explain the relationships between new predictors and existing clinical parameters. Patients from the IAEA VISION-CRT trial were used for an external validation. Heatmaps were used to interpret the AE-extracted feature.

Complete data were obtained in 130 patients, and 68.5% of them were classified as CRT responders. After variable selection by feature importance ranking and correlation analysis, one AE-extracted LVMD predictor was included in the statistical analysis. This new AE-extracted LVMD predictor showed statistical significance in the univariate (OR 2.00, P = .026) and multivariate (OR 1.11, P = .021) analyses, respectively. Moreover, the new AE-extracted LVMD predictor not only had incremental value over PBW and significant clinical variables, including QRS duration and left ventricular end-systolic volume (AUC 0.74 vs 0.72, LH 7.33, P = .007), but also showed encouraging predictive value in the 165 patients from the IAEA VISION-CRT trial (P < .1). The heatmaps for calculation of the AE-extracted predictor showed higher weights on the anterior, lateral, and inferior myocardial walls, which are recommended as LV pacing sites in clinical practice.

AE techniques have significant value in the discovery of new clinical predictors. The new AE-extracted LVMD predictor extracted from the baseline gated SPECT MPI has the potential to improve the prediction of CRT response.

To evaluate the diagnostic value of single photon emission computed tomography/computed tomography (SPECT/CT) in patients with avascular necrosis (AVN) of the femoral head.

A search of the databases PubMed, ScienceDirect, and Google Scholar was undertaken using targeted index word. Studies satisfying inclusions and exclusions criteria were identified and additional related literature sources were considered. Analysis included pooled sensitivity and specificity, odds ratio (OR), and receiver operating characteristic (ROC) analysis.

Seven studies were identified that specifically related to the diagnostic accuracy of SPECT/CT in the detection or characterisation of AVN of the femoral head. These were included in the meta-analysis. The pooled sensitivity and specificity were 94% (95% confidence interval of 87-97%) and 75% (95% confidence interval of 68-81%) respectively, the OR was 44.5 (with a 95% confidence interval of 18.2-108.6), and the area under the SROC was 93.73% (with a 95% confidence interval of 89.2%-98.3%).

This meta-analysis provides strong evidence of the high diagnostic efficacy of SPECT/CT in the evaluation of AVN of the femoral head.

In the absence of or contraindication to MRI, SPECT/CT is able to provide a suitable alternative for diagnosis of AVN of the head of femur.

The aim of the study was to explore the nature of a V-shaped sign in the backbone of the fifth lumbar vertebra revealed by whole-body bone scintigraphy (WBBS).

A local single-photon emission computed tomography (SPECT) scan plus a computed tomography (CT) scan were performed on 41 patients in our department who had a V-shaped sign in the backbone of the fifth lumbar vertebra detected by WBBS. Image fusion was conducted to understand the manifestations of the changes in the V-shaped sign in the CT images in WBBS and to determine the nature of the lesion.

All 41 patients presented with degenerative changes observed in the bilateral posterior zygapophysial joint of the fifth lumbar vertebra in the CT imaging bone window, bone hyperplasia of the articular process, joint surface hardening, and a joint gap. The vacuum sign could also be seen in some of these patients.

The typical V-shaped sign in the posterior zygapophysial joint of the fifth lumbar vertebra revealed by WBBS suggests degenerative changes in the zygapophysial joint of the fifth lumbar vertebra.

Hip osteonecrosis is a localization at the hip of aseptic osteonecrosis, a disease characterized by bone infarction. Face to a painful hip, the first examination to carry out should be a standard radiograph examination. At an early stage, the radiographs remain strictly normal MRI remains the reference examination with a sensitivity of 71-100% and specificity of 94-100%. On T2 weighting-imaging, a hyperintense line between the normal and ischemic marrow is sometimes visible; this sign is pathognomonic of bone necrosis and is known as the "double line sign". This article reviews imaging features of standard radiographs, computed tomography and MRI and addresses the role of imaging in this pathology.

Bone scintigraphy is often utilized to detect the osseous etiology of lower back pain. Here we report a 70-year-old man with lower back pain who was referred a Tc-MDP bone scan to identify possible vertebral compression fracture. The images did not detect any osseous lesion. However, the images revealed photopenic regions in the both kidneys, which were confirmed as renal cysts on the CT images. The patient received laparoscopic unroofing of renal cysts, and his symptoms improved. Our case illustrated that back pain is not always due to osseous etiology, it might be caused by urinary disorder.

Bone single-photon emission computed tomography/computed tomography (SPECT/CT) has been widely used for evaluation of femoral head viability in patients with femoral neck fracture. The current study aimed to investigate utility of standardized uptake value (SUV) from quantitative bone SPECT/CT for assessment of femoral head viability.

From March 2015 to November 2018, quantitative bone SPECT/CT was performed in 9 patients with non-viable femoral head post femoral neck fracture and in 31 controls. Maximum (SUVmax), mean (SUVmean), and minimum standardized uptake values (SUVmin) were measured over femoral head and neck. Mann-Whitney U test with Bonferroni correction was used to compare SUVs of ipsilateral and contralateral femurs from femoral neck fracture patients with those of control femurs.

As for femoral head viability, SUVmax and SUVmean were not significantly decreased in non-viable femoral heads compared to those in controls. Only the SUVmin was significantly reduced in non-viable femoral heads (mean ± standard deviation, 0.57 ± 0.38) than in controls (0.95 ± 0.26, p = 0.006) and contralateral femoral heads (1.36 ± 0.59, p = 0.008). The cutoff SUVmin of 0.61 (g/mL) yielded a sensitivity of 77.8% and specificity of 87.1% for detection of non-viable femoral heads (p = 0.006). Contralateral femoral necks of the femoral neck fracture patients showed significantly higher SUVmean and SUVmin (3.17 ± 1.20 and 1.64 ± 0.63) than those of controls (2.32 ± 0.53 and 1.04 ± 0.27; p = 0.021 and p = 0.002, respectively), which seemed to reflect weight bearing effect or metabolic derangement.

The non-viable femoral heads from the femoral neck fracture showed significantly reduced SUVmin. Quantitative bone SPECT/CT holds promise for objective evaluation of femoral head viability.

The aim of the present study was to evaluate the incidence and degree of femoral head avascularity depending on the types of femoral neck or intertrochanteric fractures using preoperative bone single photon emission computed tomography (SPECT)/computed tomography (CT).

A total of 131 patients with femoral neck or intertrochanteric fractures who underwent preoperative bone SPECT/CT were enrolled. Femoral head avascularity was evaluated using bone SPECT/CT images. Visual scores ranged from 1 to 5 based on visually assessed diagnostic confidence: 1=definitely avascular femoral head, 2=likely avascular, 3=equivocal, 4=likely not avascular, and 5=definitely not avascular. In quantitative analysis, contralateral, ipsilateral, and size ratios were measured.

Among 131 patients, 39 of 54 (72.22%) with femoral neck fractures and 23 of 77 (29.87%) with intertrochanteric fractures showed avascular femoral heads. The incidence of femoral head avascularity was significantly higher in patients with femoral neck fracture than those with intertrochanteric fracture. While the incidence and severity of femoral head avascularity increased with higher Garden stage in femoral neck fracture, neither was related to AO/Orthopaedic Trauma Association classification of intertrochanteric fracture. In addition, the number of bony fragments around intertrochanteric fractures was not a significant predictor of femoral head avascularity.

Although avascular femoral head on bone SPECT/CT does not directly indicate avascular necrosis, assessing the incidence and severity of femoral head avascularity using qualitative and quantitative parameters could give clinically useful information related to the classification. Additional studies with larger sample sizes would be a next step to expand the clinical role of bone SPECT/CT.

In this article, we discuss the role of ^99mTc-methylene diphosphonate SPECT/CT in 2 cases of slipped capital femoral epiphysis. We describe the incremental value of SPECT/CT in determining the viability of the femoral head and the implications in management of patients with slipped epiphysis.

Osteonecrosis (ON) is caused by inadequate blood supply leading to bone death, which results in the collapse of the architectural bony structure. Femoral head is the most common site involved in ON. Magnetic resonance imaging (MRI) is a commonly used imaging modality to detect early ON. When MRI is inconclusive, bone scan is helpful in detecting ON during early phase of the disease. As newer nuclear medicine equipment, like single photon emission computed tomography/computed tomography (CT) and positron emission tomography/CT, are emerging in medical science, we review the role of these imaging modalities in ON of femoral head.

To evaluate the correlation between the maximum standardised uptake value (SUVmax) from bone single-photon-emission computed tomography/computed tomography (SPECT/CT) and other imaging parameters for medial compartment osteoarthritis (OA) of the knee.

Patients (n=26; male:female=2:24; age, 55.3±5.8 years) underwent quantitative knee SPECT/CT using technetium-99m (Tc-99m) hydroxymethylene diphosphonate (HDP) before surgical operation for medial OA of the knee. SUVmax was calculated using dedicated quantitative software. Visual grades of tracer uptake on bone SPECT/CT and Kellgren-Lawrence (KL) OA scores on plain radiographs were assessed using a five-point scale. Magnetic resonance imaging (MRI) scores (n=22) and patient symptom scores were also assessed.

The operated knees (n=34) had a greater SUVmax than the non-operated knees (n=18) in the medial compartment (14.1±6.1 versus 5.3±4.4, p<0.0001). In the medial compartment, the SUVmax was significantly correlated with SPECT/CT visual grades (rho=0.794, p<0.0001), KL scores (rho=0.703, p<0.0001), and MRI scores (rho=0.714-0.808, p≤0.0002); however, SUVmax and other imaging parameters were not correlated with patient symptom scores (p>0.05).

The SUVmax of quantitative bone SPECT/CT was highly correlated with traditional imaging parameters for medial compartment OA severity of the knee. Quantitative bone SPECT/CT is a promising imaging technique for the objective assessment of knee OA.

The aim of this paper is to critically review the literature documenting the imaging approach in adult Femoral Head Avascular Necrosis (FHAVN). For this purpose we described and evaluated different radiological techniques, such as X-ray, Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Nuclear Medicine. Plain films are considered the first line imaging technique due to its ability to depict femoral head morphological changes, to its low costs and high availability. CT is not a routinely performed technique, but is useful to rule out the presence of a subchondral fracture when MRI is doubtful or contraindicated. MRI is unanimously considered the gold standard technique in the early stages, being capable to detect bone marrow changes such as edema and sclerosis. It may be useful also to guide treatment and, as CT, it is a validated technique in follow-up of patients with FHAVN. Nuclear medicine imaging is mostly applied in post-operative period to detect graft viability or infective complications. More advanced techniques may be useful in particular conditions but still need to be validated; thus new research trials are desirable. In conclusion, X-ray examination is the first line approach, but lacks of sensitivity in early stage whereas MRI is indicated. CT easily depicts late stage deformation and may decrease MRI false positive results in detecting the subchondral fracture. However, the role of both Nuclear Medicine Imaging and advanced MR techniques in FHAVN still need to be investigated.