Atypical and rare cause of myocardial infarction: coronary subclavian steal syndrome (CSSS) treated by a carotid-subclavian bypass in a 71-year-old female patient.

BACKGROUND: The coronary subclavian steal syndrome (CSSS) is a rare complication after coronary arterial bypass graft operations (CABG) using the left or right internal mammary artery ((L/R)IMA). It results from a retrograde blood flow from the IMA into the subclavian artery (SA) due to a stenosis or occlusion of the SA proximal to the IMA origin. This "steal phenomenon" leads to a decreased blood flow in the IMA and may result in myocardial ischemia (MIS) and even myocardial infarction (MIN). Treatment options include interventional and surgical therapy. CASE PRESENTATION: We report the case of a 71-year old woman, who suffered from an acute non-ST elevation myocardial infarction (NSTEMI) 11 years after LIMA-CABG surgery and who was treated successfully with a carotid-subclavian bypass (CSB) after failed interventional therapy. CONCLUSION: CSB may be regarded as a viable treatment option for patients suffering CSSS in the case of MIS and even an acute MIN/NSTEMI, especially in the case of missing or failed interventional therapy attempts. Specialists in cardiothoracic and vascular surgery should be aware of possible CSSS conditions and know about appropriate diagnostic and therapeutic options.

Whole-body ultra-low dose CT using spectral shaping for detection of osteolytic lesion in multiple myeloma.

OBJECTIVES: The aim of this study was to investigate the radiation dose and image quality of a whole-body low-dose CT (WBLDCT) using spectral shaping at 100 kV (Sn 100 kV) for the assessment of osteolytic lesions in patients with multiple myeloma. METHODS: Thirty consecutive patients were retrospectively selected, who underwent a WBLDCT on a third-generation dual-source CT (DSCT) (Sn 100 kV, ref. mAs: 130). They were matched with patients, who were examined on a second-generation DSCT with a standard low-dose protocol (100 kV, ref. mAs: 111). Objective and subjective image quality, radiation exposure as well as the frequency of osteolytic lesions were evaluated. RESULTS: All scans were of diagnostic image quality. Subjective overall image quality was significantly higher in the study group (p = 0.0003). Objective image analysis revealed that signal intensities, signal-to-noise ratio and contrast-to-noise ratio of the bony structures were equal or significantly higher in the control group. There was no significant difference in the frequency of osteolytic lesions (p = 0.259). The median effective dose of the study protocol was significantly lower (1.45 mSv vs. 5.65 mSv; p < 0.0001). CONCLUSION: WBLDCT with Sn 100 kV can obtain sufficient image quality for the depiction of osteolytic lesions while reducing the radiation dose by approximately 74%. KEY POINTS: • Spectral shaping using tin filtration is beneficial for whole-body low-dose CT • Sn 100 kV yields sufficient image quality for depiction of osteolytic lesions • Whole-body low-dose CT can be performed with a median dose of 1.5 mSv.

Submillisievert standard-pitch CT pulmonary angiography with ultra-low dose contrast media administration: A comparison to standard CT imaging.

OBJECTIVES: To evaluate the image quality and radiation dose of submillisievert standard-pitch CT pulmonary angiography (CTPA) with ultra-low dose contrast media administration in comparison to standard CTPA. MATERIALS AND METHODS: Hundred patients (56 females, 44 males, mean age 69.6±15.4 years; median BMI: 26.6, IQR: 5.9) with suspected pulmonary embolism were examined with two different protocols (n = 50 each, group A: 80 kVp, ref. mAs 115, 25 ml of contrast medium; group B: 100 kVp, ref. mAs 150, 60 ml of contrast medium) using a dual-source CT equipped with automated exposure control. Objective and subjective image qualities, radiation exposure as well as the frequency of pulmonary embolism were evaluated. RESULTS: There was no significant difference in subjective image quality scores between two groups regarding pulmonary arteries (p = 0.776), whereby the interobserver agreement was excellent (group A: k = 0.9; group B k = 1.0). Objective image analysis revealed that signal intensities (SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the pulmonary arteries were equal or significantly higher in group B. There was no significant difference in the frequency of pulmonary embolism (p = 0.65). Using the low dose and low contrast media protocol resulted in a radiation dose reduction by 71.8% (2.4 vs. 0.7 mSv; p<0.001). CONCLUSIONS: This 80 kVp standard pitch CTPA protocol with 25 ml contrast agent volume can obtain sufficient image quality to exclude or diagnose pulmonary emboli while reducing radiation dose by approximately 71%.

Quantification of congenital aortic valve stenosis in pediatric patients: comparison between cardiac magnetic resonance imaging and transthoracic echocardiography.

Previous studies showed the reliability of cardiac magnetic resonance imaging (cMRI) in the quantification of aortic valve stenosis in adults. The aim of this retrospective study was to assess the ability of cMRI in the quantification of congenital aortic valve stenosis (CAS) in children. Nineteen patients (mean age 14.0 ± 3.2 years, 15 boys and 4 girls) with CAS were imaged by cMRI and transthoracic echocardiography (TTE). cMRI was performed on a 1.5-Tesla MR scanner (Magnetom Avanto; Siemens Healthcare, Erlangen, Germany) using cine steady-state free precession sequences for the assessment of the aortic valve area (AVA) by MR planimetry and left-ventricular function. Phase-contrast measurement was used in cMRI to assess peak flow velocity above the aortic valve. A positive correlation was found between maximum systolic pressure gradient (MPG) as assessed by cMRI and TTE (28.9 ± 21.2 vs. 41.3 ± 22.7 mmHg, r = 0.84, p = 0.001) with a mean underestimation of 12.4 mmHg by cMRI. Only a weak correlation could be observed between AVA by cMRI and MPG at the aortic valve by TTE (r = -0.50, p = 0.029) and cMRI (r = -0.27, p = 0.40). Furthermore, a positive correlation between myocardial mass (cMRI) and MPG (TTE, r = 0.57, p = 0.01), but not between myocardial mass (cMRI) and AVA (cMRI, r = 0.07, p = 0.77), was found. The assessment of MPG by cMRI in patients with CAS is feasible with a trend toward underestimatation compared with TTE. Moreover, MPG seems to be a more accurate parameter than AVA regarding the prediction of myocardial hypertrophy.

Diagnosis and dosimetry in differentiated thyroid carcinoma using 124I PET: comparison of PET/MRI vs PET/CT of the neck.

PURPOSE: This study compares intrinsically coregistered 124I positron emission tomography (PET) and CT (PET/CT) and software coregistered 124I PET and MRI (PET/MRI) images for the diagnosis and dosimetry of thyroid remnant tissues and lymph node metastases in patients with differentiated thyroid carcinoma (DTC). METHODS: After thyroidectomy, 33 high-risk DTC patients (stage III or higher) received 124I PET/CT dosimetry prior to radioiodine therapy to estimate the absorbed dose to lesions and subsequently underwent a contrast-enhanced MRI examination of the neck. Images were evaluated by two experienced nuclear medicine physicians and two radiologists to identify the lesions and to categorize their presumable provenience, i.e. thyroid remnant tissue (TT), lymph node metastasis (LN) and inconclusive tissue. The categorization and dosimetry of lesions was initially performed with PET images alone (PET only). Subsequently lesions were reassessed including the CT and MRI data. RESULTS: The analyses were performed on a patient and on a lesion basis. Patient-based analyses showed that 26 of 33 (79%) patients had at least one lesion categorized as TT on PET only. Of these patients, 11 (42%) and 16 (62%) had a morphological correlate on CT and MRI, respectively, in at least one TT PET lesion. Twelve patients (36%) had at least one lesion classified as LN on PET only. Nine (75%) of these patients had a morphological correlate on both CT and MRI in at least one LN PET lesion. Ten patients (30%) showed at least one lesion on PET only classified as inconclusive. The classification was changed to a clear classification in two patients (two LN) by CT and in four (two TT, two LN) patients by MRI. Lesion-based analyses (n=105 PET positive lesions) resulted in categorization as TT in 61 cases (58%), 16 (26%) of which had a morphological correlate on CT and 33 (54%) on MRI. A total of 29 lesions (27%) were classified as LN on PET, 18 (62%) of which had a morphological correlate on CT and 24 (83%) on MRI. In 16 lesions (15%) PET alone allowed no definite categorization. Categorization was achieved with the aid of CT and MRI, respectively, in five (one TT, four LN) and in six (two TT, four LN) lesions. In direct comparison, 23 lesions were not discernible on CT but clearly visible on MRI, 15 of which were smaller than 10 mm and about two thirds were classified as TT. Redoing dosimetry based on the volume information from MRI for these small lesions would have changed the initial therapy regime in five patients. These patients would have received (131)I therapy with standardized activities of 3.7 GBq or 7.4 GBq instead of activities higher than 10 GBq and would have benefited from reduced radiation exposure. CONCLUSION: PET/MRI is superior to PET/CT in terms of tracing back a PET focus to a morphological correlate. For this reason PET/MRI enhances diagnostic certainty for lesions<10 mm and improves pretherapeutic lesion dosimetry in DTC.