Changing Threshold-Based Segmentation Has No Relevant Impact on Semi-Quantification in the Context of Structured Reporting for PSMA-PET/CT.

Prostate-specific membrane antigen (PSMA)-directed positron emission tomography/computed tomography (PET/CT) is increasingly utilized for staging of men with prostate cancer (PC). To increase interpretive certainty, the standardized PSMA reporting and data system (RADS) has been proposed. Using PSMA-RADS, we characterized lesions in 18 patients imaged with 18F-PSMA-1007 PET/CT for primary staging and determined the stability of semi-quantitative parameters. Six hundred twenty-three lesions were categorized according to PSMA-RADS and manually segmented. In this context, PSMA-RADS-3A (soft-tissue) or -3B (bone) lesions are defined as being indeterminate for the presence of PC. For PMSA-RADS-4 and -5 lesions; however, PC is highly likely or almost certainly present [with further distinction based on absence (PSMA-RADS-4) or presence (PSMA-RADS-5) of correlative findings on CT]. Standardized uptake values (SUVmax, SUVpeak, SUVmean) were recorded, and volumetric parameters [PSMA-derived tumor volume (PSMA-TV); total lesion PSMA (TL-PSMA)] were determined using different maximum intensity thresholds (MIT) (40 vs. 45 vs. 50%). SUVmax was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories (p ≤ 0.0322). In particular, the clinically challenging PSMA-RADS-3A lesions showed significantly lower SUVmax and SUVpeak compared to the entire PSMA-RADS-4 or -5 cohort (p < 0.0001), while for PSMA-RADS-3B this only applies when compared to the entire PSMA-RADS-5 cohort (p < 0.0001), but not to the PSMA-RADS-4 cohort (SUVmax, p = 0.07; SUVpeak, p = 0.08). SUVmean (p = 0.30) and TL-PSMA (p = 0.16) in PSMA-RADS-5 lesions were not influenced by changing the MIT, while PSMA-TV showed significant differences when comparing 40 vs. 50% MIT (p = 0.0066), which was driven by lymph nodes (p = 0.0239), but not bone lesions (p = 0.15). SUVmax was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories in 18F-PSMA-1007 PET/CT. As such, the latter parameter may assist the interpreting molecular imaging specialist in assigning the correct PSMA-RADS score to sites of disease, thereby increasing diagnostic certainty. In addition, changes of the MIT in PSMA-RADS-5 lesions had no significant impact on SUVmean and TL-PSMA in contrast to PSMA-TV.

Interplatform reproducibility of CT coronary calcium scoring software.

PURPOSE: To investigate whether coronary artery calcium (CAC) scoring performed on three different workstations generates comparable and thus vendor-independent results. MATERIALS AND METHODS: Institutional review board and Federal Office for Radiation Protection approval were received, as was each patient's written informed consent. Fifty-nine patients (37 men, 22 women; mean age, 57 years±3 [standard deviation]) underwent CAC scoring with use of 64-section multidetector computed tomography (CT) with retrospective electrocardiographic gating (one examination per patient). Data sets were created at 10% increments of the R-R interval from 40%-80%. Two experienced observers in consensus calculated Agatston and volume scores for all data sets by using the calcium scoring software of three different workstations. Comparative analysis of CAC scores between the workstations was performed by using regression analysis, Spearman rank correlation (rs), and the Kruskal-Wallis test. RESULTS: Each workstation produced different absolute numeric results for Agatston and volume scores. However, statistical analysis revealed excellent correlation between the workstations, with highest correlation at 60% of the R-R interval (minimal rs=0.998; maximal rs=0.999) for both scoring methods. No significant differences were detected for Agatston and volume score results between the software platforms. At analysis of individual reconstruction intervals, each workstation demonstrated the same score variability, with the consequence that 12 of 59 patients were assigned to divergent cardiac risk groups by using at least one of the workstations. CONCLUSION: While mere numeric values might be different, commercially available software platforms produce comparable CAC scoring results, which suggests a vendor-independence of the method; however, none of the analyzed software platforms appears to provide a distinct advantage for risk stratification, as the variability of CAC scores depending on the reconstruction interval persists across platforms.

Hemodynamic assessment of severe aortic stenosis: MRI evaluation of dynamic changes of vena contracta.

PURPOSE: Direct magnetic resonance imaging (MRI) planimetry of the maximal systolic aortic valve area does not consider temporal variations of the opening area during the ejection period. We evaluated an MRI-based methodology for the assessment of valvular dynamics in patients with severe aortic stenosis by measuring the systolic variability of the valvular blood stream, that is, the "vena contracta." MATERIALS AND METHODS: With institutional review board approval, we examined 22 patients (13 male, 9 female; mean age, 68 ±10 years) with severe aortic stenosis using 1.5 T MRI and a standardized scanning protocol consisting of gradient-echo phase-contrast velocity imaging and steady-state free precession-cine MRI before and after valve replacement therapy. Temporal changes of the aortic valve area, represented by systolic variations of the area of poststenotic turbulent flow at its smallest convergence, that is, the proximal vena contracta, were determined by MRI and quantified by a calculated parameter of temporal valve dynamics (T). T was defined as the period which the aortic valve spent over its maximal opening area (>85%) during systole. MRI was also used to determine left ventricular hypertrophy before (LVMI) and its regression (LVMR) after valve replacement. Findings were compared with transthoracic echocardiography and cardiac catheterization. RESULTS: All patients had an echocardiographic effective orifice area, EOATTE, of <1.0 cm2. The comparison of T to LVMI and LVMR revealed significant correlations (LVMI: r = -0.62; P = 0.002; LVMR: r = 0.62; P = 0.002). Further significant correlations with aortic stenosis severity were observed in the comparison with manual planimetry, invasive measurements, and echocardiographic valve areas, as well as with pressure gradients. CONCLUSIONS: MRI can measure systolic variations of the aortic valve area. Quantitative parameters of the hemodynamic relevance of valve dynamics obtained by this method correlate with established parameters of aortic stenosis severity and LVMR.

Emergency computed tomography for aortic valve vegetation mimicking disruption.

A 47-year-old man presented with symptoms typical of infective endocarditis and history of streptococcal meningitis 8 months previously. Echocardiography showed a large aortic valve vegetation that was interpreted as disruption of the noncoronary cusp. This was ruled out by 64-slice cardiac computed tomography. Valve replacement was performed successfully.

The worst case: giant exulcerating seminoma.

Ten years after his brother had been treated for seminoma, a 36-year-old male presented with a giant exulcerating mass involving the right testis and both inguinal regions. Subsequent biopsy revealed pure seminoma. Staging computed tomography (CT) showed bulky retroperitoneal and pelvic lymph node metastases. After seven courses of cisplatin-based chemotherapy, positron emission tomography suggested residual tumor in the right groin. The suspicious lesion and the right testis were resected showing no vital tumor tissue. Eight months after surgery there were no signs of disease progression at follow-up CT.

Heartmate II implantation with right coronary bypass grafting in ischemic cardiomyopathy with "fixed" pulmonary hypertension: treatment strategy to protect right ventricular function.

A 49-year-old male patient suffering from end-stage ischemic cardiomyopathy with a left ventricular ejection fraction below 15% was presented to redo coronary artery bypass grafting (CABG). Coronary angiogram demonstrated an occluded left anterior descending artery and occluded right coronary artery, perfused retrogradely from the circumflex artery. Since positron emission tomography did not demonstrate viable left ventricular myocardium except for the basis of the left ventricle, CABG was considered futile. Cardiac transplantation was contra-indicated due to pharmacologically unresponsive pulmonary artery hypertension. The patient successfully underwent left ventricular assist device implantation in combination with right coronary artery revascularization. The article reflects the regimen of right ventricular preservation in this patient.

Intratracheal growth of recurrent benign goiter.

BACKGROUND: Intratracheal goiter manifestations caused by ectopic thyroid tissue have occasionally been reported. We report a 42-year-old female who had undergone thyroid surgery twice, which had caused unilateral recurrent laryngeal nerve palsy. SUMMARY: The patient presented with progressive dyspnea. Magnetic resonance imaging showed a recurrent goiter growing through the tracheal wall. She was treated in a multidisciplinary approach; at first she underwent transtracheal laser surgical removal of the intratracheal mass followed by conventional completion thyroidectomy and radioiodine remnant ablation. Thorough histological analysis did not find any signs of malignancy. Currently the patient is disease- and complaint free. As far as we could ascertain, no patient with a recurrent benign goiter growing through the tracheal wall has been reported before. CONCLUSION: Recurrent benign goiter with intratracheal growth is extremely rare and requires a multidisciplinary approach.

Quantitative contrast-enhanced perfusion measurements of the human lung using the prebolus approach.

PURPOSE: To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). MATERIALS AND METHODS: Eleven volunteers were examined by applying different contrast agent doses (0.5, 1.0, 2.0, and 3.0 mL gadolinium diethylene triamine pentaacetic acid [Gd-DTPA]), using a saturation-recovery (SR) true fast imaging with steady precession (TrueFISP) sequence. PBF and PBV were determined for single bolus and prebolus. Region of interest (ROI) evaluation was performed and parameter maps were calculated. Additionally, cardiac output (CO) and lung volume were determined and GLP was calculated as a contrast agent-independent reference value. RESULTS: The prebolus results showed good agreement with low-dose single-bolus and GLP: PBF (mean +/- SD in units of mL/minute/100 mL) = single bolus 190 +/- 73 (0.5-mL dose) and 193 +/- 63 (1.0-mL dose); prebolus 192 +/- 70 (1.0-2.0-mL dose) and 165 +/- 52 (1.0-3.0-mL dose); GLP (mL/minute/100 mL) = 187 +/- 34. Higher single-bolus resulted in overestimated values due to arterial input function (AIF) saturation. CONCLUSION: The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps.

Whole-body MRI of multiple myeloma: comparison of different MRI sequences in assessment of different growth patterns.

PURPOSE: To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM). METHODS AND MATERIALS: WB-MRI using a 1.5T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63+/-12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n=7; intermediate-grade, n=7; high-grade, n=9) and to the staging system of Durie and Salmon PLUS (stage I, n=12; stage II, n=4; stage III, n=7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57+/-13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1+/-CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis. RESULTS: Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1+/-CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1+/-CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1=60%; 2=36%; 3=83%; T2: 1=70%; 2=71%; 3=89%; T1+/-CE/T2: 1=50%; 2=50%; 3=89%) and clinical stage (T1: 1=58%; 2=63%; 3=79%; T2: 1=58%; 2=88%; 3=100%; T1+/-CE/T2: 1=50%; 2=63%; 3=100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers). CONCLUSIONS: T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.

Multi-slice cardiac computed tomography reveals anomalous origin of the right coronary artery between the great arteries.

We report a case of a 72-year-old man whose multi-slice cardiac computed tomography revealed an anomalous origin of the right coronary artery between the great arteries.

Ultrasound and MRI features of pyomyositis in children.

Pyomyositis (PM) is an infectious disease of the skeletal muscle with a wide range of symptoms such as pain, fever or swelling, and is predominantly found in the tropics. In recent years PM has increasingly been diagnosed in Europe and in the U.S. Our objective is to describe the ultrasound and MRI features of PM in children. A retrospective analysis of 12 children with PM (2 girls and 10 boys; age range 1-13 years) admitted to our hospital between 1998 and 2002 was carried out. All children had a US exam and 8 children underwent MRI. Children with osteomyelitis and accompanying myositis were excluded from this study. In all patients who had MRI ( n=8) the infected muscles were found to have the following features: hyperintensity on the T2-weighted images, diffuse borders and contrast enhancement. In the pelvis ( n=4), only one PM could be detected with US, in the other 3 cases only US of the hip joint was performed based on the clinical symptoms. In the extremities ( n=8) US always revealed an altered echogenicity of the affected muscles as well as fluid collection in 5 cases. Both US and MRI reveal characteristic changes of the PM. Ultrasound should be the first imaging modality in the extremities. In the pelvis MRI is the imaging modality of choice. The MRI is needed to differentiate pyomyositis from osteomyelitis.

Fibrosing mediastinitis with superior vena cava obstruction as the initial presentation of Langerhans' cell histiocytosis in a young child.

We present a 2-year-old girl with an unusual presentation of Langerhans' cell histiocytosis (LCH). Five months prior to admission to our hospital, she received IV steroids for bronchial obstruction. On admission, clinical signs of SVC obstruction were evident and a mediastinal mass was evident on the chest radiograph and MRI. Biopsy revealed fibrosing mediastinitis. Five months later, osteolysis was present on a skull radiograph. Surgical biopsy of the skull lesion revealed LCH. This case is unique because it demonstrates a rare initial manifestation of LCH that has not been previously reported. Furthermore, the primary, solitary mediastinal manifestation without calcifications was histologically interpreted as fibrosing mediastinitis, and the final diagnosis of LCH was only made after identifying the skull lesion.

The pattern of skeletal anomalies in the cervical spine, hands and feet in patients with Saethre-Chotzen syndrome and Muenke-type mutation.

BACKGROUND: Saethre-Chotzen syndrome (SCS) and Muenke-type mutation (MTM) are complex syndromes with craniosynostosis and skeletal anomalies including syndactyly, carpal and tarsal fusions, and cervical spine abnormalities. OBJECTIVE: In this study, we analysed radiographs of the cervical spine, hands and feet of a large patient population with genetically proven SCS and MTM. The aim was to describe the pattern of skeletal anomalies and to determine whether specific features are present that could help differentiate between the two entities. MATERIALS AND METHODS: Radiographs of 43 patients (23 males, 20 females) with SCS (n=35) or MTM (n=8) were evaluated. The median age was 8 years (range 1 month-36 years). All radiographs were reviewed by two radiologists. RESULTS: In the hands and feet, a variety of anomalies such as brachyphalangy, clinodactyly, partial syndactyly, partial carpal or tarsal fusion, and cone-shaped epiphyses were noted. Duplicated distal phalanx of the hallux (n=12/35) and triangular deformity of the epiphysis of the distal phalanx of the hallux (n=10/35) were detected in SCS only; calcaneo-cuboid fusion (n=2/35) was detected in MTM only. In the cervical spine, fusion of vertebral bodies and/or the posterior elements occurred only in patients with SCS. CONCLUSIONS: Pathognomonic signs for SCS are the triangular shape of the epiphysis and duplicated distal phalanx of the hallux. Calcaneo-cuboid fusion was detected in MTM only. These signs may be helpful in the differentiation of SCS from MTM.