Interaction of impaired myocardial flow reserve and extent of myocardial ischemia assessed using 13N-ammonia positron emission tomography imaging on adverse cardiovascular outcomes.

BACKGROUND: Myocardial flow reserve (MFR) and the extent of myocardial ischemia identify patients at high risk of major adverse cardiovascular events (MACEs). Associations between positron emission tomography (PET)-assessed extent of ischemia, MFR, and MACEs is unclear. METHOD: Overall, 640 consecutive patients with suspected or known coronary artery disease undergoing 13N-ammonia myocardial perfusion PET were followed-up for MACEs. Patients were categorized into three groups based on myocardial ischemia severity: Group I (n = 335), minimal (myocardial ischemia < 5%); Group II (n = 150), mild (5-10%); and Group III (n = 155), moderate-to-severe (> 10%). RESULTS: Cardiovascular death and MACEs occurred in 17 (3%) and 93 (15%) patients, respectively. Following statistical adjustment for confounding factors, impaired MFR (global MFR < 2.0) was revealed as an independent predictor of MACEs in Groups I (hazard ratio [HR], 2.89; 95% confidence interval [CI], 1.48-5.64; P = 0.002) and II (HR, 3.40; 95% CI 1.37-8.41; P = 0.008) but was not significant in Group III (HR, 1.15; 95% CI 0.59-2.26; P = 0.67), with a significant interaction (P < 0.0001) between the extent of myocardial ischemia and MFR. CONCLUSION: Impaired MFR was significantly associated with increased risk of MACEs in patients with ≤ 10% myocardial ischemia but not with those having > 10% ischemia, allowing a clinically effective risk stratification.

Prognostic value of modified coronary flow capacity by 13N-ammonia myocardial perfusion positron emission tomography in patients without obstructive coronary arteries.

BACKGROUND: Vasodilator capacity of coronary circulation is an important diagnostic and prognostic tool in patients with coronary artery disease (CAD). We aimed to clarify the incidence of coronary microvascular dysfunction (CMD), defined as impaired modified coronary flow capacity (mCFC) proposed by Johnson and Gould and measured by 13N-ammonia myocardial perfusion positron emission tomography (PET), in patients without obstructive CAD and to evaluate the risk of future cardiovascular events. METHODS: This retrospective study recruited 407 consecutive CAD-suspected patients who underwent both pharmacological stress/rest 13N-ammonia PET and coronary angiography. Of the 407 patients, 137 patients (median age, 70 years; 63 women) were eligible and followed up (median, 19.8 months). Endpoints were defined as cardiovascular death or major adverse cardiovascular events (MACEs), such as cardiovascular death, nonfatal myocardial infarction, unplanned hospitalization for any cardiac reasons, and unplanned coronary revascularization. The impaired mCFC group included patients with mildly to severely reduced regional CFC in, at least, one vascular territory (n=34), while the remaining patients (n=103) were categorized as having preserved mCFC. RESULTS: Overall, cardiovascular death and MACEs occurred in five (4%) patients. The Kaplan-Meier curve showed a significant reduction in event-free survival for cardiovascular death (p=0.004) and MACEs (p<0.0001) in the impaired mCFC group, compared to the preserved mCFC group. Impaired mCFC was independently associated with the incidence of both cardiovascular death and MACEs after propensity-score adjustments [hazard ratio (HR), 10.7; 95% confidence interval (CI), 1.0-106.0; p=0.04 and HR, 9.5; 95% CI, 2.5-36.2; p<0.001, respectively]. CONCLUSIONS: In CAD-suspected patients without obstructive coronary arteries, impaired mCFC was observed in approximately 25% and was associated with a higher risk of cardiovascular death and MACEs. The mCFC concept can help identify patients who would benefit from specific therapies or lifestyle modifications to prevent future MACEs and can clarify potential mechanisms of CMD.

Visualization of Quantitative Flow Reduction with 4D-flow Magnetic Resonance Imaging in a Patient with Pelvic Arteriovenous Malformation After Transcatheter Arterial Embolization.

A 54-year-old man was admitted to our hospital with dyspnea and heart failure. Contrast-enhanced computed tomography showed a giant pelvic arteriovenous malformation (AVM) fed by the left internal iliac artery (IIA), right IIA, and inferior mesenteric artery. (IMA). The AVM was treated with selective embolization via the left IIA. Time-resolved three-dimensional phase-contrast magnetic resonance imaging (4D-flow MRI) visualized a gradual flow reduction in the left IIA, whereas the flow in the IMA and right IIA increased relatively. After four sessions, the patient experienced symptom relief and the blood level of N-terminal prohormone brain natriuretic peptide decreased. To the best of our knowledge, we present the first reported use of 4D-flow MRI to quantitatively assess flow reduction in the case of pelvic AVM after embolization.

Preservation of deep inferior epigastric artery at kidney transplantation prevents atrophy of lower rectus abdominis muscle.

BACKGROUNDS: The deep inferior epigastric artery (DIEA), which feeds the lower rectus abdominis muscle (lower RAM), is usually transected in kidney transplantation. In this study, we investigated whether preservation of DIEA can prevent lower RAM atrophy. METHODS: Two hundred and forty-five kidney transplant recipients (150 men and 95 women) were enrolled in the study (mean age 39.9 years) and were divided into two groups according to whether DIEA was transected (group A, n = 175) or preserved (group B, n = 70). The extent of lower RAM atrophy calculated in computed tomography (performed 1 year after transplantation) and incidence of lower RAM atrophy were compared between the two groups. The most predictive factors for lower RAM atrophy were assessed using a multivariate logistic regression model. RESULTS: The extent of lower RAM atrophy was significantly lower in group B (15.0 ± 18.5%) than that in group A (38.9 ± 25.4%, P = 0.003). The incidence of lower RAM atrophy was less prevalent in group B (20.0%) compared with that in group A (62.9%, P < 0.001). The sacrifice of DIEA was the only independent predictive factor for lower RAM atrophy (P < 0.001). CONCLUSIONS: Preservation of DIEA during kidney transplant can prevent lower RAM atrophy.

(99m)Tc-DTPA dynamic SPECT and CT volumetry for measuring split renal function in live kidney donors.

OBJECTIVES: Split renal function (SRF) estimated from the posterior view of (99m)Tc-diethylenetriaminepentaacetic acid planar scintigraphy (DTPA/P) is not sufficiently accurate even after correction for kidney depth by computed tomography (CT). To obtain more accurate SRF using (99m)Tc-DTPA, dynamic SPECT method was carried out for the initial 5 min after bolus injection of (99m)Tc-DTPA (DTPA/SPECT). Also SRF was evaluated from the renal volume measured by CT. We compared the results with (99m)Tc-dimercaptosuccinic acid SPECT (DMSA/SPECT). METHODS: In 60 consecutive live kidney donors, 30 DTPA/P, 30 DTPA/SPECT, 60 (99m)Tc-DMSA/SPECT, and 60 CT studies were performed. In the DTPA/P studies, SRF was calculated from the posterior image recorded during 2-3-min postinjection with attenuation correction for kidney depth measured by CT. In the DTPA/SPECT studies, SPECT images were acquired continuously for 5 min with a dual-headed gamma camera. In (99m)Tc-DMSA scintigraphy, DMSA/SPECT images were acquired 3-h postinjection. The SRF on both SPECT studies was calculated from the total counts of each kidney. In the DTPA/SPECT study, SRF was evaluated on the three images summed for 1 min: 1-2 min (DTPA/SPECT1-2), 2-3 min (DTPA/SPECT2-3), and 1-3 min (DTPA/SPECT1-3). In the CT examination, to assess the global renal volume, the axial images in the excretory phase were chosen. Renal contours were identified on each image, and the areas (cm(2)) of these regions were summed and multiplied by the slice thickness (10 mm) to yield global renal volume (ml). Right renal function from DTPA/P, DTPA/SPECT, and CT were compared with that from DMSA/SPECT as a reference. RESULTS: Correlation coefficients of the right renal function between DMSA/SPECT and DTPA/P, DTPA/SPECT2-3, and CT were 0.663, 0.849 and 0.907, respectively (P < 0.0001). The differences between DMSA/SPECT and DTPA/P, DTPA/SPECT2-3 and CT were 2.42 +/- 3.878, 0.867 +/- 1.672, and -0.421 +/- 1.077% (mean +/- SD), respectively. CONCLUSION: SRF derived from DTPA/SPECT showed a better correlation with DMSA/SPECT and significantly fewer errors (P < 0.05) than DTPA/P. A significant strong correlation was observed between SRF from DMSA/SPECT and CT, indicating the utility of CT renal volumetry for evaluating SRF.

[Neonatal cystic structure adjacent to frontal horn--MRI features].

PURPOSE: To evaluate the incidence and features of cystic structures adjacent to the frontal horns of neonates using MRI, and to assess the clinical features of the neonates. MATERIALS AND METHODS: Between April 2001 and January 2005, MRI examinations were performed at our hospital in 352 neonates and infants whose postconceptional age was less than 48 weeks. We retrospectively evaluated the MRI findings and the clinical records. RESULTS: Seventeen babies (8 males and 9 females) showed cystic structures adjacent to frontal horns, hemilaterally or bilaterally. The incidence of the cysts was 4.8% in total, and was 1.4% (1/74), 9.2% (6/65), and 4.7% (10/213)in term infants, preterm infants born at 33-36 weeks of gestational age, and at less than 32 weeks, respectively. The cysts ranged from 1 to 8 mm in diameter, and were located in the white matter adjacent to ventricular walls and in the portion cephalad to the frontal horns. The cysts resolved in 5 cases (with follow-up ranging from 3 months to 2 years of age), causing slight dilatation of the frontal horn. Developmental disturbances were not observed in patients without other abnormalities. CONCLUSION: Cystic structures near the frontal horns in neonates are detected by MRI at a rate of 4.8%. They will resolve spontaneously without causing developmental abnormalities.

Tc-99m MDP bone scintigraphy of myositis as a manifestation of chronic graft-versus-host disease after non-myeloablative peripheral stem cell transplantation.

A 27-year-old man developed polymyositis as a manifestation of chronic graft-versus-host disease (GVHD) after non-myeloablative peripheral blood stem cell transplantation (PBSCT). Bone scintigraphy showed intense, striped, and heterogeneous accumulation of Tc-99m methylene diphosphonate (MDP) in the soft-tissue of his lower limbs, while faint activities were seen in the right upper limb. Tc-99m MDP scintigraphy was very useful for accurate and objective evaluation of the severity of the muscle injury and the extent of polymyositis caused by chronic GVHD.

A case of intravascular lymphoma with increased regional cerebral blood flow in I-123 IMP single-photon emission CT.

This report documents a case of intravascular lymphoma (IVL) with increased regional cerebral blood flow (rCBF) disclosed at I-123 IMP single-photon emission CT (IMP-SPECT). A 73-year-old woman with IVL had high rCBF disclosed by IMP-SPECT before chemotherapy; rCBF was normal after one course of CHOP (cyclophophamide, vincristine, doxorubicin, and prednisone) chemotherapy. During her clinical course, she had an episode in which she showed increased rCBF in the left cerebral hemisphere at IMP-SPECT performed immediately after the recovery from the right hemiparesis.