Hiromitsu Hayashi

Three-dimensional CT angiography of intracranial vasospasm following subarachnoid haemorrhage

Abstract We evaluated the usefulness of three-dimensional CT angiography (3D-CTA) in the diagnosis of intracranial vasospasm following subarachnoid haemorrhage (SAH) in 13 patients suspected of having vasospasm on clinical grounds. The intracranial vessels were clearly shown by 3D-CTA in 12 patients. 3D-CTA revealed spasm in the vessels of nine patients. Catheter angiography performed in seven of these patients immediately after 3D-CTA confirmed vasospasm. A low-attenuation area was seen on CT in the other two patients, representing an ischaemic lesion due to the spasm. In nine patients, a second 3D-CTA was performed using the same technique 1 week after the first, showing no vasospasm. Initial 3D-CTA revealed no vasospasm change in three patients. Following 3D-CTA, one of these had conventional angiography, which also demonstrated no spasm.

Transjugular intrahepatic portosystemic shunt in a patient with cavernomatous portal vein occlusion

A 23-year-old woman with liver cirrhosis secondary to primary sclerosing cholangitis was referred to us for the treatment of recurrent bleeding from esophageal varices that had been refractory to endoscopic sclerotherapy. Her portal vein was occluded, associated with cavernous transformation. A transjugular intrahepatic portosystemic shunt (TIPS) was performed after a preprocedural three-dimensional computed tomographic angiography evaluation to determine feasibility. The portal vein system was recanalized and portal blood flow increased markedly after TIPS. Esophageal varices disappeared 3 weeks after TIPS. Re-bleeding and hepatic encephalopathy were absent for 3 years after the procedure. We conclude that with adequate preprocedural evaluation, TIPS can be performed safely even in patients with portal vein occlusion associated with cavernous transformation.

Contrast-induced nephropathy in patients with renal insufficiency undergoing contrast-enhanced MDCT

AbstractObjectivesTo evaluate the safety of contrast-enhanced MDCT in patients with renal impairment.MethodsWe conducted a retrospective review of 938 patients with stable renal insufficiency (eGFR between 15 and 60xa0ml/min) who underwent contrast-enhanced MDCT. SCr levels were measured at baseline and 48–72xa0h after contrast medium administration. The incidence of contrast-induced nephropathy (CIN) in the total study population was assessed. As a control group, 1,164 separate patients with renal insufficiency who did not receive contrast medium for CT were also reviewed.ResultsThe overall incidence of CIN in the patient population with renal insufficiency was 6.1xa0%; the incidence was 4.4xa0%, 10.5xa0% and 10.0xa0% for patients whose eGFR was 45–60, 30–45 and ≤30xa0ml/min, respectively (Pu2009<u20090.01). In the control group, 5.8xa0% of patients showed an increase in the SCr level from the baseline. The increase in the SCr level showed no significant difference between the patients who received CM and those who did not (Pu2009=u20090.82)ConclusionsThe risk of CIN from contrast-enhanced MDCT in patients with renal insufficiency appeared to be low, and there was no significant difference in the incidence of CIN in comparison with patients who did not receive CM.Key Points• The contrast medium used for multidetector CT can induce nephropathy.n • Contrast-induced nephropathy (CIN) developed in 6.1xa0% of patients with renal insufficiency.n • However, nephropathy developed in 5.8xa0% of similar patients not receiving contrast medium.n • Thus, the risk of CIN associated with MDCT appears to be low.n • Special care should still be taken in patients with renal insufficiency.

Metallic artifacts of coronary and iliac arteries stents in mr angiography and contrast-enhanced CT

Metallic artifacts of intravascular stents were assessed with MR angiography and contrast-enhanced spiral CT. Stainless steel showed less metal artifact than tantalum stent in CT. Metallic artifact in coronary and iliac arteries treated with tantalum stent was not remarkable in MR angiography. Contrast-enhanced CT might be preferable to assess patency of arteries treated with stainless steel stent. while MR angiography was useful in depicting intraluminal signal in tantalum stent.

Guidelines on the use of iodinated contrast media in patients with kidney disease 2012: digest version

Open image in new window What is the definition of CIN? n nAnswer: n nCIN is defined as an increase in serum creatinine (SCr) levels by ≥0.5 mg/dL or ≥25 % from baseline within 72 h after a contrast radiography using iodinated contrast media. nOpen image in new window n n nBecause the risk for developing CIN increases as kidney function decreases, it is important to evaluate kidney function on the basis of the latest SCr levels prior to contrast radiography. According to the classification of the severity of CKD, which is based on the cause, GFR, and presence and severity of albuminuria (Table 1) [1], patients with a GFR of <60 mL/min/1.73 m2 (G3a–G5) are considered to have CKD in this guideline. In another words, CKD is also diagnosed in patients with a GFR of ≥60 mL/min/1.73 m2 and albuminuria, in the present guidelines only patients with a GFR of <60 mL/min/1.73 m2 are defined as having CKD. n n nTable 1 nClassification of severity of CKD (2012) n n n n nOpen image in new window n n n nRisks of ESKD requiring dialysis or transplantation, and risks for cardiovascular diseases such as stroke, myocardial infarction, and heart failure are coded with colors ranging from green (lowest), yellow, orange and red (highest) n nCKD chronic kidney disease, Cr creatinine, ESKD end-stage kidney disease, GFR glomerular filtration rate n nAdapted from KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Inter Suppl. 2013;3:19–62 [1], with permission from Nature Publishing Group., modified for Japanese patients n n n n nThe following formula is used to calculate estimated GFR (eGFR). nOpen image in new window n n nCIN is a form of acute kidney injury (AKI) that occurs after exposure to iodinated contrast media, and is diagnosed on the basis of reducing kidney function after contrast radiography when other causes such as cholesterol embolism are ruled out. AKI due to CIN is generally reversible. Usually, SCr levels increase to a peak 3–5 days after onset, and return to normal in 7–14 days. However, kidney injury may worsen to the point that hemodialysis is required in some patients. n nThe criteria for the diagnosis of CIN used in clinical research of this condition vary among studies. The minimum increment of SCr levels that defined CIN included 0.5 mg/dL, 1.0 mg/dL, and 25 % or 50 % from baseline, and the duration of monitoring for CIN included 24 h, 48 h, 72 h, 4 days, and 7 days after contrast radiography. The most commonly used criteria for CIN in clinical research is an increase in SCr levels by ≥0.5 mg/dL or ≥25 % from baseline within 72 h after contrast radiography. However, physicians in the clinical setting should not wait for 72 h, and should start close monitoring of SCr levels from an early stage when CIN is suspected. The incidence of CIN, and clinical characteristics such as patients’ baseline kidney function, vary depending on the criteria used for diagnosis. Standardized diagnostic criteria are necessary to promote clinical research of this condition and develop preventive procedures. nOpen image in new window n nOpen image in new window

Detection and characterization of focal liver lesions using superparamagnetic iron oxide-enhanced magnetic resonance imaging: comparison between ferumoxides-enhanced T1-weighted imaging and delayed-phase gadolinium-enhanced T1-weighted imaging

AbstractBackground: Double contrast magnetic resonance (MR) imaging using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) is performed to detect and characterize focal liver lesions. However, this technique is a costly and lengthy process. The purpose of this study was to determine the usefulness of SPIO-enhanced MR imaging including SPIO-enhanced T1-weighted imaging in diagnosing focal liver lesions.nMethods: Eighty-four focal liver lesions were examined with a 1.5-T MR unit. Transverse precontrast T1- and T2-weighted images and SPIO (ferumoxides)-enhanced T1- and T2-weighted images were obtained, followed by Gd-enhanced T1-weighted imaging. The Gd set (i.e., precontrast T1- and T2-weighted and delayed-phase gadolinium-enhanced T1-weighted images) and ferumoxides set (i.e., precontrast T1- and ferumoxides-enhanced T1- and T2-weighted images) were reviewed by two independent readers.nResults: More lesions were detected from the ferumoxides set than from the Gd set. Ferumoxides-enhanced T1-weighted imaging showed enhancement patterns of the lesions similar to those of delayed-phase Gd-enhanced T1-weighted imaging. The diagnoses of hepatic metastasis and cyst by the ferumoxides set were similar to those by the Gd set. However, a dynamic study may be inevitable for the diagnosis of hepatocellular carcinoma and hemangioma.nConclusion: The ferumoxides set was useful for the detection of focal hepatic lesions. Ferumoxides-enhanced T1-weighted imaging may replace delayed-phase gadolinium-enhanced T1-weighted imaging in the diagnosis of hepatic metastasis and cysts.

Gd-DTPA enhanced MRI of reactive hematopoietic regions in marrow.

Objective The purpose of this report was to study the contrast enhancement of reactive hematopoietic regions in bone marrow on Gd-diethylenetriamine pentaacetic acid (DTPA) enhanced MRI. Materials and Methods We compared the contrast enhancement of reactive hematopoietic regions in the marrow of patients with aplastic anemia and drug-induced pancytopenia and that of normal bone marrow on Gd-DTPA enhanced MRI. Results The reactive hematopoietic marrow observed in aplastic anemia of moderate grade and drug-induced pancytopenia markedly enhanced after Gd-DTPA administration; normoplastic marrow showed no enhancement. Conclusion Gd-DTPA enhanced MRI was useful in detecting the reactive hematopoietic regions in bone marrow.

Application of multidetector-row computed tomography in propeller flap planning.

Background: The propeller flap is defined as (1) being island-shaped, (2) having an axis that includes the perforators, and (3) having the ability to be rotated around an axis. The advantage of the propeller flap is that it is a pedicle flap that can be applied to cover defects located at the distal ends of the extremities. The specific aims of the authors study were (1) to evaluate the usefulness of multidetector-row computed tomography in the planning of propeller flaps and (2) to present a clinical case series of propeller flap reconstructions that were planned preoperatively using multidetector-row computed tomography. Methods: The authors retrospectively analyzed all cases between April of 2007 and April of 2010 at Nippon Medical School Hospital in Tokyo, where multidetector-row computed tomography was used preoperatively to plan surgical reconstructions using propeller flaps. Results: Thirteen patients underwent 16 flaps using the propeller flap technique. The perforators were identified accurately by multidetector-row computed tomography preoperatively in all cases. Conclusions: This is the first report describing the application of multidetector-row computed tomography in the planning of propeller flaps. Multidetector-row computed tomography is superior to other imaging methods because it demonstrates more precisely the perforators position and subcutaneous course using high-resolution three-dimensional images. By using multidetector-row computed tomography to preoperatively identify a flaps perforators, the surgeon can better plan the flap design to efficiently conduct the flap surgery.

Anemia and the risk of contrast-induced nephropathy in patients with renal insufficiency undergoing contrast-enhanced MDCT

PURPOSEnThe purpose of this study was to assess the effect of anemia on the incidence of contrast-induced nephropathy (CIN) in patients with renal impairment undergoing MDCT.nnnMATERIALS AND METHODSnInstitutional review board approval was waived for this retrospective review of 843 patients with stable renal insufficiency (eGFR between 15 and 60 mL/min) who had undergone contrast-enhanced MDCT. Baseline hematocrit and hemoglobin values were measured. Serum creatinine (SCr) was assessed at the baseline and at 48-72 h after contrast administration.nnnRESULTSnThe overall incidence of CIN in the patient population with renal insufficiency was 6.9%. CIN developed in 7.8% (54 of 695) of anemic patients, and in 2.8% (4 of 148) of non-anemic patients (P=.027). After adjustment for confounders, low hemoglobin and low hematocrit values remained independent predictors of CIN (odds ratio 4.6, 95% CI 1.0-20.5, P=.046).nnnCONCLUSIONSnAnemia is associated with a higher incidence of CIN in patients with renal insufficiency. Anemia is a potentially modifiable risk factor for CIN, and has an unfavorable impact on prognosis in patients with renal insufficiency undergoing contrast-enhanced MDCT.

Invasive pulmonary aspergillosis occluding the descending aorta and left pulmonary artery: CT features.

Invasive pulmonary aspergillosis (IPA) has been recognized as an infectious complication in immunocompromised patients. We present a case of IPA, which occluded the descending aorta and left pulmonary artery and led to death after antileukemic chemotherapy. Contrast-enhanced CT demonstrated thrombi in the great vessels as low attenuation areas. These thrombi became extensive despite intensive antibiotic and antifungal therapy. Microscopic examination revealed that the thrombi contained aspergillus hyphae, and occlusions of both great vessels were induced by direct extension of aspergillus. This case illustrates that IPA can be the cause of great vessel occlusion in immunocompromised patients. We describe the CT and autopsy findings of this case and emphasize the virulence of this fungus.