Regional myocardial damage and active inflammation in patients with cardiac sarcoidosis detected by non-invasive multi-modal imaging

Aims

Cardiac sarcoidosis (CS) can be diagnosed using ¹⁸F-FDG-PET/CT (PET), cardiovascular magnetic resonance (CMR), and ¹²³I-BMIPP/²⁰¹TlCl dual myocardial SPECT. This study aims to clarify the relationships among the three modalities with respect to CS.

Methods and results

We evaluated 16 patients (male n = 11; age 55 ± 13 years) with confirmed CS who underwent PET, CMR, and dual SPECT with gated SPECT before starting steroid therapy. The left ventricular myocardium was divided into 17 segments to obtain SUVmax for PET images, defect scores from 0 to 4 (0 normal; 4 absent), and mismatch scores for dual SPECT (BMDS, TLDS, and MS) images and late gadolinium enhancement (LGE) scores (0 none; 1 partly positive; 2 homogeneous) on CMR images. Summed BMDS, TLDS, and MS were 18.6 ± 12.6, 12.9 ± 10.9, and 5.7 ± 3.1, respectively. The segmental BMDS and TLDS scores became significantly higher as the LGE scores increased. The MS scores were significantly higher in areas of LGE with a score of 1 than 0 (both, p < 0.001), but did not significantly differ between areas with LGE scores of 1 and 2. The SUVmax was significantly higher in LGE areas with a score of 1 than 0 (p < 0.025), but did not significantly differ between those with scores of 1 or 2.

Conclusion

Regions with a higher SUVmax indicating active myocardial inflammation were mainly located in areas with LGE, where BMIPP and TL mismatches were evident in patients with CS.

     

Hybrid <Superscript>18</Superscript>F–FDG PET/MRI might improve locoregional staging of breast cancer patients prior to neoadjuvant chemotherapy

Purpose

Our purpose in this study was to assess the added clinical value of hybrid ¹⁸F–FDG-PET/MRI compared to conventional imaging for locoregional staging in breast cancer patients undergoing neoadjuvant chemotherapy (NAC).

Methods

In this prospective study, primary invasive cT2-4 N0 or cT1-4 N+ breast cancer patients undergoing NAC were included. A PET/MRI breast protocol was performed before treatment. MR images were evaluated by a breast radiologist, blinded for PET images. PET images were evaluated by a nuclear physician. Afterwards, a combined PET/MRI report was written. PET/MRI staging was compared to conventional imaging, i.e., mammography, ultrasound and MRI. The proportion of patients with a modified treatment plan based on PET/MRI findings was analyzed.

Results

A total of 40 patients was included. PET/MRI was of added clinical value in 20.0% (8/40) of patients, changing the treatment plan in 10% and confirming the malignancy of suspicious lesions on MRI in another 10%. In seven (17.5%) patients radiotherapy fields were extended because of additional or affirmative PET/MRI findings being lymph node metastases (n = 5) and sternal bone metastases (n = 2). In one (2.5%) patient radiotherapy fields were reduced because of fewer lymph node metastases on PET/MRI compared to conventional imaging. Interestingly, all treatment changes were based on differences in number of lymph nodes suspicious for metastasis or number of distant metastasis, whereas differences in intramammary tumor extent were not observed.

Conclusion

Prior to NAC, PET/MRI shows promising results for locoregional staging compared to conventional imaging, changing the treatment plan in 10% of patients and potentially replacing PET/CT or tissue sampling in another 10% of patients.

     

MRI fused with prone FDG PET/CT improves the primary tumour staging of patients with breast cancer

Objective

Our aim was to evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) fused with prone 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in primary tumour staging of patients with breast cancer.

Methods

This retrospective study evaluated 45 women with 49 pathologically proven breast carcinomas. MRI and prone PET-CT scans with time-of-flight and point-spread-function reconstruction were performed with the same dedicated breast coil. The studies were assessed by a radiologist and a nuclear medicine physician, and evaluation of fused images was made by consensus. The final diagnosis was based on pathology (90 lesions) or follow-up?≥?24 months (17 lesions).

Results

The study assessed 72 malignant and 35 benign lesions with a median size of 1.8 cm (range 0.3–8.4 cm): 31 focal, nine multifocal and nine multicentric cases. In lesion-by-lesion analysis, sensitivity, specificity, positive and negative predictive values were 97%, 80%, 91% and 93% for MRI, 96%, 71%, 87%, and 89% for prone PET, and 97%. 94%, 97% and 94% for MRI fused with PET. Areas under the curve (AUC) were 0.953, 0.850, and 0.983, respectively (p?<?0.01).

Conclusions

MRI fused with FDG-PET is more accurate than FDG-PET in primary tumour staging of breast cancer patients and increases the specificity of MRI.

Key points

? FDG PET-CT may improve the specificity of MRI in breast cancer staging.? MRI fused with prone 2-[fluorine-18]-fluoro-2-deoxy-D-glucose PET-CT has better overall diagnostic performance than MRI.? The clinical role of fused PET-MRI has not yet been established.

     

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma

Objective

To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.

Methods

54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar’s test.

Results

Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.

Conclusion

FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

     

A preliminary report of breast cancer screening by positron emission mammography

Objective

Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) and PET/computed tomography (PET/CT) have had a considerable impact on the detection of various malignancies. PET and PET/CT are minimally invasive methods that can provide whole-body imaging at one time. Therefore, an FDG-PET cancer screening program has been widely used in Japan. However, the breast cancer detection rate of FDG-PET cancer screening is relatively low. Therefore, FDG-PET screening is not recommended for breast cancer screening. Positron emission mammography (PEM) is a high-resolution molecular breast imaging technology. PEM can detect small breast cancers that cannot be detected on PET or PET/CT images due to limited spatial resolution. We have performed opportunistic breast cancer screening using PEM since 2011. To the best of our knowledge, this is the first report regarding PEM breast cancer screening.

Methods

This study enrolled 265 women. PEM images were analyzed by agreement of 2 experienced nuclear medicine physicians. The readers were given information from medical interview sheet. US findings were interpreted holistically. The number of participants, patient recall rate, further examination rate, and cancer detection rate by year were calculated.

Results

The overall recall rate was 8.3 %; the work-up examination rate was 77.3 %, and cancer detection rate was 2.3 %. The positive predictive value of PEM was 27.3 %. Six cancers were found by PEM screening. Five were invasive cancers and one was ductal carcinoma in situ. Histological tumor sizes were reported in three cases: 0.7, 1.2, and 2 cm.

Conclusion

PEM screening appears to have potential for breast cancer screening.

     

Image fusion between 18F-FDG PET and MRI in cardiac sarcoidosis: A case series

Background

Sarcoidosis is a systemic disorder of unknown etiology. It is distinguished by the presence of noncaseating epithelioid granulomas. This study demonstrates the use of image fusion between (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG PET) and magnetic resonance imaging (MRI) to diagnose patients with cardiac sarcoidosis (CS).

Methods

Seven patients diagnosed with sarcoidosis were retrospectively included. All patients underwent 18F-FDG PET/CT and cardiac MRI.

Results

On the MRI scan, late gadolinium enhancement (LGE) was observed in five patients. T2-weighted images revealed areas with an increased signal consistent with myocardial edema in two patients and with hypointensity suggesting fibrosis in one patient. Increased 18F-FDG uptake was seen in the myocardial wall in three patients, indicating active inflammation.

Conclusion

18F-FDG PET and MRI image fusion allows clinicians to obtain complete morphofunctional cartography in patients with sarcoidosis. Our data show that 18F-FDG PET/MRI image fusion imaging can be useful in the diagnosis of CS.

     

Clinical and magnetic resonance evolution of “infarct-like” myocarditis

Aims

To analyse the clinical and magnetic resonance evolution of myocarditis in patients with an “infarct-like” presentation pattern.

Methods

The study is a retrospective analysis of 52 patients with clinical diagnosis of “infarct-like” myocarditis confirmed by CMR as acute myocarditis according to Lake Louise criteria and 6 months follow-up. The CMR protocol included T2-weighted (oedema), early (hyperaemia) and late (fibrosis/necrosis) gadolinium enhancement sequences, according to Lake Louise criteria. Clinical and radiological follow-up by CMR was performed after a median time interval of 6 months (interquartile range 5–8). Quantitative outcomes were checked for normality and compared with the non-parametric Wilcoxon’s test for matched data.

Results

At the clinical follow-up all patients were free of symptoms and reported no cardiac complications. The CMR follow-up evidenced a significant increase of the ejection fraction (from 53 ± 6 to 55 ± 4%, p = 0.03), a decrease of the ventricular mass [from 67.0 (58.8–79.0) to 61.0 (54.0–67.0), p < 0.0001] without significant modification of the cardiac volume index (p = 0.26). No patient had residual oedema or capillary leakage: the T2 ratio decreased from 3.94 (3.00–4.86) to 0.98 (0.75–1.17) with p < 0.0001 and the Early gadolinium enhancement (EGE) ratio from 5.7 (4.8–6.5) to 2.9 (2.4–3.2) with p < 0.0001. Late gadolinium enhancement (LGE) persisted over the course of the follow-up in 48/52 patients, but with a significant reduction in every patient (LGE % from 34.3 ± 9.1 to 19.4 ± 6.6%; p < 0.0001).

Conclusion

Patients diagnosed with “infarct-like” myocarditis, according to both clinical and CMR examinations may look forward to a positive evolution with a good prognosis.

     

Integrated 18F–FDG PET/MRI compared to MRI alone for identification of local recurrences of soft tissue sarcomas: a comparison trial

Purpose

To assess and compare the diagnostic accuracy of PET/MRI and MRI alone for the detection of local recurrences of soft tissue sarcomas (STS) after initial surgical resection of the primary tumors.

Material and methods

A total of 41 patients with clinically suspected tumor relapse of STS underwent an ¹⁸F–FDG-PET/MRI examination for assessment of local recurrence. Two experienced physicians interpreted the MRI data and subsequently the PET/MRI datasets in two separate reading sessions and were instructed to identify potential local tumor recurrences. Additionally, the diagnostic confidence in each reading for the identification of malignant lesions was determined. A McNemar test was applied to test for differences of both ratings and a Wilcoxon signed-rank test was used to identify differences of the confidence levels. Histopathological verification and follow-up imaging were applied for standard of reference.

Results

Tumor relapse was present in 27/41 patients. Calculated sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for the detection of local tumor recurrence was 82%, 86%, 92%, 71% and 83% for MRI, and 96%, 79%, 90%, 92% and 90% for PET/MRI (p > 0.05). Furthermore, PET/MRI showed significantly higher confidence levels (p < 0.05) for the determination of malignant lesions.

Conclusion

Our results endorse ¹⁸F–FDG PET/MRI to be an excellent imaging method in the evaluation of recurrent STS after surgical excision, yielding superior tumor detection when compared to MRI alone.

     

Assessment of radiological techniques application possibility for non-invasive diagnostics of latent inflammatory processes in myocardium in patients with atrial fibrillation

Objective

Aim was to study the performance of single-photon emission computed tomography (SPECT) with ^99mTc-pyrophosphate (^99mTc-PYP) in diagnostics of chronic latent inflammation in myocardium of patients with atrial fibrillation (AF).

Methods

The research included 70 patients (the average age of 49.3 ± 10.2 years) with persistent form of idiopathic AF. All patients underwent myocardium SPECT with ^99mTc-PYP and cardiac magnetic resonance imaging (CMR) before the ablation. During the ablation endomyocardium sampling for histological and immunohistochemical verification of myocarditis was performed.

Results

Sensitivity of SPECT with ^99mTc-PYP in diagnoses of chronic latent myocarditis in patients with AF in relation to endomyocardial biopsy was 80 %, specificity—83 % and diagnostic accuracy—82 %. Sensitivity, specificity and diagnostic accuracy of myocardium perfusion scintigraphy for diagnostics of latent myocarditis in relation to endomyocardial biopsy was 30, 50 and 50 % correspondingly. Also the close correlation between the size of the perfusion defect and the severity of myocardial fibrosis in patients with AF was revealed. Specificity of the Lake Louise criteria for diagnostics of latent myocarditis in relation to endomyocardial biopsy was 77.6 %, sensitivity—60 % and diagnostic accuracy—74.5 %. For only LGE specificity was 16 %, sensitivity—90 % and diagnostic accuracy—28 %.

Conclusions

The study showed the possibility of successful application of radionuclide methods for diagnoses of chronic latent myocarditis at AF. Taking into account high informative values the results of scintigraphy can be also considered as a promising additional criteria for selecting patients with AF of unexplained etiology for non-invasive endomyocardial biopsy procedure.

     

Additive value of 320-section low-dose dynamic volume CT in relation to 3-T MRI for the preoperative evaluation of brain tumors

Purpose

To assess whether 320-section low-dose dynamic volume computed tomography (320-LDVCT) with adaptive iterative dose reduction (AIDR) adds value to 3-T MRI for the preoperative evaluation of brain tumors.

Methods

The study population was comprised of 16 consecutive patients with brain tumors who, in addition to preoperative 3-T MRI, underwent 320-LDVCT with AIDR. Two radiologists independently evaluated the CT and MRI studies; one measured the relative cerebral blood volume (rCBV) in the tumor and contralateral brain on CT and MR perfusion maps. Interobserver agreement was assessed by κ statistics.

Results

In 3 of 16 patients (19 %), 320-LDVCT added diagnostic value to 3-T MRI studies with respect to the visualization of feeders (κ = 0.77), and in 12 (75 %) it helped the delineation of venous structures (κ = 0.71) and the relationship between the tumor and adjacent vessels (κ = 0.85). The average standardized rCBV value was 12.2 ± 2.40 (range 0.7–36.6) on MR and 8.80 ± 2.77 (range 0.8–38.0) on CT perfusion studies; the correlation between these values was very strong (r = 0.92, p < 0.0001). According to the neurosurgeons, 320-LDVCT added helpful information for surgery in 4 patients (25 %).

Conclusion

The 320-LDVCT can add value to 3-T MRI for the tumor feeders and relationship between the tumor and adjacent vessels.

     

The diagnostic value of <Superscript>18</Superscript>F–FDG-PET/CT and MRI in suspected vertebral osteomyelitis – a prospective study

Purpose

The aim of this study was to determine the diagnostic value of ¹⁸F–fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) and magnetic resonance imaging (MRI) in diagnosing vertebral osteomyelitis.

Methods

From November 2015 until December 2016, 32 patients with suspected vertebral osteomyelitis were prospectively included. All patients underwent both ¹⁸F–FDG-PET/CT and MRI within 48 h. All images were independently reevaluated by two radiologists and two nuclear medicine physicians who were blinded to each others’ image interpretation. ¹⁸F–FDG-PET/CT and MRI were compared to the clinical diagnosis according to international guidelines.

Results

For ¹⁸F–FDG-PET/CT, sensitivity, specificity, PPV, and NPV in diagnosing vertebral osteomyelitis were 100%, 83.3%, 90.9%, and 100%, respectively. For MRI, sensitivity, specificity, PPV, and NPV were 100%, 91.7%, 95.2%, and 100%, respectively. MRI detected more epidural/spinal abscesses. An important advantage of ¹⁸F–FDG-PET/CT is the detection of metastatic infection (16 patients, 50.0%).

Conclusion

¹⁸F–FDG-PET/CT and MRI are both necessary techniques in diagnosing vertebral osteomyelitis. An important advantage of ¹⁸F–FDG-PET/CT is the visualization of metastatic infection, especially in patients with bacteremia. MRI is more sensitive in detection of small epidural abscesses.

     

Cardiac index after acute ST-segment elevation myocardial infarction measured with phase-contrast cardiac magnetic resonance imaging

Objectives

Phase-contrast CMR (PC-CMR) might provide a fast and robust non-invasive determination of left ventricular function in patients after ST-segment elevation myocardial infarction (STEMI).

Methods

Cine sequences in the left-ventricular (LV) short-axis and free-breathing, retrospectively gated PC-CMR were performed in 90 patients with first acute STEMI and 15 healthy volunteers. Inter- and intra-observer agreement was determined. The correlations of clinical variables (age, gender, ejection fraction, NT pro-brain natriuretic peptide [NT-proBNP] with cardiac index (CI) were calculated.

Results

For CI, there was a strong agreement of cine CMR with PC-CMR in healthy volunteers (r: 0.82, mean difference: -0.14 l/min/m², error?±?23 %). Agreement was lower in STEMI patients (r: 0.61, mean difference: -0.17 l/min/m², error?±?32 %). In STEMI patients, CI measured with PC-CMR showed lower intra-observer (1 % vs. 9 %) and similar inter-observer variability (9 % vs. 12 %) compared to cine CMR. CI was significantly correlated with age, ejection fraction and NT-proBNP values in STEMI patients.

Discussion

The agreement of PC-CMR and cine CMR for the determination of CI is lower in STEMI patients than in healthy volunteers. After acute STEMI, CI measured with PC-CMR decreases with age, LV ejection fraction and higher NT-proBNP.

Key Points

? Cine CMR and PC-CMR correlate well in healthy volunteers.? Agreement is lower in STEMI patients.? Cardiac Output should be measured with one method longitudinally.? Cardiac output decreases with age after myocardial infarction.

     

Voxel-wise correlation of functional imaging parameters in HNSCC patients receiving PET/MRI in an irradiation setup

Purpose

The purpose of this study was to demonstrate the feasibility of voxel-wise multiparametric characterization of head and neck squamous cell carcinomas (HNSCC) using hybrid multiparametric magnetic resonance imaging and positron emission tomography with [¹⁸F]-fluorodesoxyglucose (FDG-PET/MRI) in a radiation treatment planning setup.

Methods

Ten patients with locally advanced HNSCC were examined with a combined FDG-PET/MRI in an irradiation planning setup. The multiparametric imaging protocol consisted of FDG-PET, T2-weighted transverse short tau inversion recovery sequence (STIR) and diffusion-weighted MRI (DWI). Primary tumours were manually segmented and quantitative imaging parameters were extracted. PET standardized uptake values (SUV) and DWI apparent diffusion coefficients (ADC) were correlated on a voxel-wise level.

Results

Images acquired in this specialised radiotherapy planning setup achieved good diagnostic quality. Median tumour volume was 4.9 [1.1–42.1]?ml. Mean PET SUV and ADC of the primary tumours were 5?±?2.5 and 1.2?±?0.3 10^?3?mm²/s, respectively. In voxel-wise correlation between ADC values and corresponding FDG SUV of the tumours, a significant negative correlation was observed (r?=??0.31?±?0.27, p?<?0.05).

Conclusion

Multiparametric voxel-wise characterization of HNSCC is feasible using combined PET/MRI in a radiation planning setup. This technique may provide novel insights into tumour biology with regard to radiation therapy in the future.

     

Late gadolinium enhancement cardiac imaging on a 3T scanner with parallel RF transmission technique: prospective comparison of 3D-PSIR and 3D-IR

Objective

To qualitatively and quantitatively compare different late gadolinium enhancement (LGE) sequences acquired at 3T with a parallel RF transmission technique.

Methods

One hundred and sixty participants prospectively enrolled underwent a 3T cardiac MRI with 3 different LGE sequences: 3D Phase-Sensitive Inversion-Recovery (3D-PSIR) acquired 5 minutes after injection, 3D Inversion-Recovery (3D-IR) at 9 minutes and 3D-PSIR at 13 minutes. All LGE-positive patients were qualitatively evaluated both independently and blindly by two radiologists using a 4-level scale, and quantitatively assessed with measurement of contrast-to-noise ratio and LGE maximal surface. Statistical analyses were calculated under a Bayesian paradigm using MCMC methods.

Results

Fifty patients (70 % men, 56yo?±?19) exhibited LGE (62 % were post-ischemic, 30 % related to cardiomyopathy and 8 % post-myocarditis). Early and late 3D-PSIR were superior to 3D-IR sequences (global quality, estimated coefficient IR?>?early-PSIR : -2.37 CI?=?[-3.46 ; -1.38], prob(coef?>?0)?=?0 % and late-PSIR?>?IR : 3.12 CI?=?[0.62 ; 4.41], prob(coef?>?0)?=?100 %), LGE surface estimated coefficient IR?>?early-PSIR: -0.09 CI?=?[-1.11; -0.74], prob(coef?>?0)?=?0 % and late-PSIR?>?IR : 0.96 CI?=?[0.77; 1.15], prob(coef?>?0)?=?100 %). Probabilities for late PSIR being superior to early PSIR concerning global quality and CNR were over 90 %, regardless of the aetiological subgroup.

Conclusions

In 3T cardiac MRI acquired with parallel RF transmission technique, 3D-PSIR is qualitatively and quantitatively superior to 3D-IR.

Key Points

? Late gadolinium enhancement is an essential part of a cardiac MRI examination ? PSIR and IR sequences are the two possible options for LGE imaging ? At 3T with parallel RF transmission, PSIR sequences are significantly better ? One LGE sequence is sufficient, allowing an optimization of the acquisition time

     

Simultaneous whole-body <Superscript>18</Superscript>F–PSMA-1007-PET/MRI with integrated high-resolution multiparametric imaging of the prostatic fossa for comprehensive oncological staging of patients with prostate cancer: a pilot study

Introduction

The aim of the present study was to explore the clinical feasibility and reproducibility of a comprehensive whole-body ¹⁸F–PSMA-1007-PET/MRI protocol for imaging prostate cancer (PC) patients.

Methods

Eight patients with high-risk biopsy-proven PC underwent a whole-body PET/MRI (3 h p.i.) including a multi-parametric prostate MRI after ¹⁸F–PSMA-1007-PET/CT (1 h p.i.) which served as reference. Seven patients presented with non-treated PC, whereas one patient presented with biochemical recurrence. SUV_mean-quantification was performed using a 3D–isocontour volume-of-interest. Imaging data was consulted for TNM-staging and compared with histopathology. PC was confirmed in 4/7 patients additionally by histopathology after surgery. PET-artifacts, co-registration of pelvic PET/MRI and MRI-data were assessed (PI-RADS 2.0).

Results

The examinations were well accepted by patients and comprised 1 h. SUV_mean-values between PET/CT (1 h p.i.) and PET/MRI (3 h p.i.) were significantly correlated (p < 0.0001, respectively) and similar to literature of ¹⁸F–PSMA-1007-PET/CT 1 h vs 3 h p.i. The dominant intraprostatic lesion could be detected in all seven patients in both PET and MRI. T2c, T3a, T3b and T4 features were detected complimentarily by PET and MRI in five patients. PET/MRI demonstrated moderate photopenic PET-artifacts surrounding liver and kidneys representing high-contrast areas, no PET-artifacts were observed for PET/CT. Simultaneous PET-readout during prostate MRI achieved optimal co-registration results.

Conclusions

The presented ¹⁸F–PSMA-1007-PET/MRI protocol combines efficient whole-body assessment with high-resolution co-registered PET/MRI of the prostatic fossa for comprehensive oncological staging of patients with PC.

     

Evaluation of ECG-gated [<Superscript>11</Superscript>C]acetate PET for measuring left ventricular volumes,mass, and myocardial external efficiency

Background

Noninvasive estimation of myocardial external efficiency (MEE) requires measurements of left ventricular (LV) oxygen consumption with [¹¹C]acetate PET in addition to LV stroke volume and mass with cardiovascular magnetic resonance (CMR). Measuring LV geometry directly from ECG-gated [¹¹C]acetate PET might enable MEE evaluation from a single PET scan. Therefore, we sought to establish the accuracy of measuring LV volumes, mass, and MEE directly from ECG-gated [¹¹C]acetate PET.

Methods

Thirty-five subjects with aortic valve stenosis underwent ECG-gated [¹¹C]acetate PET and CMR. List mode PET data were rebinned into 16-bin ECG-gated uptake images before measuring LV volumes and mass using commercial software and compared to CMR. Dynamic datasets were used for calculation of mean LV oxygen consumption and MEE.

Results

LV mass, volumes, and ejection fraction measured by CMR and PET correlated strongly (r = 0.86-0.92, P < .001 for all), but were underestimated by PET (P < .001 for all except ESV P = .79). PET-based MEE, corrected for bias, correlated fairly with PET/CMR-based MEE (r = 0.60, P < .001, bias ?3 ± 21%, P = .56). PET-based MEE bias was strongly associated with LV wall thickness.

Conclusions

Although analysis-related improvements in accuracy are recommended, LV geometry estimated from ECG-gated [¹¹C]acetate PET correlate excellently with CMR and can indeed be used to evaluate MEE.

     

Simultaneous whole-body and breast 18F-FDG PET/MRI examinations in patients with breast cancer: a comparison of apparent diffusion coefficients and maximum standardized uptake values

Purpose

To compare standardized uptake value (SUV) and apparent diffusion coefficient (ADC) values acquired using a PET/MRI scanner in breast cancer patients.

Materials and methods

Whole-body PET/MRI and breast PET/MRI were performed in 108 consecutive patients. Ninety-four patients who had a total of 100 breast cancers were analyzed. SUVmax and ADCmean acquired using breast PET/MRI were compared with pathologic prognostic factors.

Results

All the lesions were visually detectable using PET and diffusion-weighted imaging (DWI) on breast PET/MRI; however, lesions were visually undetectable on whole-body DWI in 13 patients (13%) or on whole-body PET in 7 patients (7%). An analysis of ADCmean and SUVmax demonstrated a statistically significant correlation between whole-body imaging and breast imaging (rho = 0.613, p < 0.001 and rho = 0.928, p < 0.001, respectively). In a univariate analysis, SUVmax was significantly correlated with HER2 status (p < 0.001), Ki-67 (p = 0.014), tumor size (p = 0.0177), and nuclear grade (p = 0.0448). In multiple regression analysis, only tumor size (p = 0.00701) was shown to independently influence SUVmax.

Conclusion

Prone breast imaging was more sensitive than whole-body PET/MRI for detection of breast cancers. Both SUVmax and ADCmean showed limited correlation with pathologic prognostic factors.

     

Mean and maximum standardized uptake values in [<Superscript>18</Superscript>F]FDG-PET for assessment of histopathological response in oesophageal squamous cell carcinoma or adenocarcinoma after radiochemotherapy

Purpose

To evaluate the potential of [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the assessment of histopathological response and survival after neoadjuvant radiochemotherapy in patients with oesophageal cancer.

Patients and methods

In 2005 and 2006, 55 patients (43 men, 12 women; median age 60 years) with locally advanced oesophageal cancer (cT3-4 Nx M0; 24 with squamous cell carcinoma, 31 with adenocarcinoma) underwent transthoracic en bloc oesophagectomy after completion of treatment with cisplatin, 5-fluorouracil, and radiotherapy ad 36 Gy in a prospective clinical trial. Of the 55 patients, 21 (38%) were classified as histopathological responders (<10% vital residual tumour cells) and 34 (62%) as nonresponders. FDG-PET was performed before (PET 1) and 3–4 weeks after the end (PET 2) of radiochemotherapy with assessment of maximum and average standardized uptake values (SUV) for correlation with histopathological response and survival.

Results

Histopathological responders had a slightly higher baseline SUV than nonresponders (p<0.0001 between PET 1 and PET 2 for responders and nonresponders) and the decrease was more prominent in responders. Except for SUVmax in patients with squamous cell carcinoma neither baseline nor preoperative SUV nor percent SUV reduction correlated significantly with histopathological response. Histopathological responders had a 2-year overall survival of 91?±?9% and nonresponders a survival of 53?±?10% (p?=?0.007).

Conclusion

Our study does not support recent reports that FDG-PET predicts histopathological response and survival in patients with locally advanced oesophageal cancer treated by neoadjuvant radiochemotherapy.

     

Differentiation of myocardial ischemia and infarction assessed by dynamic computed tomography perfusion imaging and comparison with cardiac magnetic resonance and single-photon emission computed tomography

Objectives

To evaluate the feasibility of myocardial blood flow (MBF) by computed tomography from dynamic CT perfusion (CTP) for detecting myocardial ischemia and infarction assessed by cardiac magnetic resonance (CMR) or single-photon emission computed tomography (SPECT).

Methods

Fifty-three patients who underwent stress dynamic CTP and either SPECT (n?=?25) or CMR (n?=?28) were retrospectively selected. Normal and abnormal perfused myocardium (ischemia/infarction) were assessed by SPECT/CMR using 16-segment model. Sensitivity and specificity of CT-MBF (mL/g/min) for detecting the ischemic/infarction and severe infarction were assessed.

Results

The abnormal perfused myocardium and severe infarction were seen in SPECT (n?=?90 and n?=?19 of 400 segments) and CMR (n?=?223 and n?=?36 of 448 segments). For detecting the abnormal perfused myocardium, sensitivity and specificity were 80 % (95 %CI, 71-90) and 86 % (95 %CI, 76-91) in SPECT (cut-off MBF, 1.23), and 82 % (95 %CI, 76-88) and 87 % (95 %CI, 80-92) in CMR (cut-off MBF, 1.25). For detecting severe infarction, sensitivity and specificity were 95 % (95 %CI, 52-100) and 72 % (95 %CI, 53-91) in SPECT (cut-off MBF, 0.92), and 78 % (95 %CI, 67-97) and 80 % (95 %CI, 58-86) in CMR (cut-off MBF, 0.98), respectively.

Conclusions

Dynamic CTP has a potential to detect abnormal perfused myocardium and severe infarction assessed by SPECT/CMR using comparable cut-off MBF.

Key Points

? CT-MBF accurately reflects the severity of myocardial perfusion abnormality. ? CT-MBF provides good diagnostic accuracy for detecting myocardial perfusion abnormalities. ? CT-MBF may assist in stratifying severe myocardial infarction in abnormal perfusion myocardium.

     

T1 mapping using saturation recovery single-shot acquisition at 3-tesla magnetic resonance imaging in hypertrophic cardiomyopathy: comparison to late gadolinium enhancement

Purpose

We evaluated the T1 values of segments and slices and the reproducibility in healthy controls, using saturation recovery single-shot acquisition (SASHA) at 3T magnetic resonance imaging. Moreover, we examined the difference in T1 values between hypertrophic cardiomyopathy (HCM) and healthy controls, and compared those with late gadolinium enhancement (LGE).

Materials and methods

Twenty-one HCM patients and 10 healthy controls underwent T1 mapping before and after contrast administration. T1 values were measured in 12 segments.

Results

Native T1 values were significantly longer in HCM than in healthy controls [1373 ms (1312–1452 ms) vs. 1279 ms (1229–1326 ms); p < 0.0001]. Even in HCM segments without LGE, native T1 values were significantly longer than in healthy control segments [1366 ms (1300–1439 ms) vs. 1279 ms (1229–1326 ms); p < 0.0001]. Using a cutoff value of 1327 ms for septal native T1 values, we differentiated between HCM and healthy controls with 95% sensitivity, 90% specificity, 94% accuracy, and an area under the curve of 0.95.

Conclusions

Native T1 values using a SASHA at 3T could differentiate HCM from healthy controls. Moreover, native T1 values have the potential to detect abnormal myocardium that cannot be identified adequately by LGE in HCM.