Kenji Itani

Evaluation of the hemodynamics of the femoral head compared with the ilium, femoral neck and femoral intertrochanteric region in healthy adults : measurement with positron emission tomography (PET)

ObjectiveNon-traumatic osteonecrosis of the femoral head (ONF) is considered to be a disease that occurs primarily due to ischemia of the femoral head, while its etiology and pathology are not fully understood. It is therefore necessary to identify the characteristics of the hemodynamics of the femoral head. In this study, the hemodynamics in the ilium and proximal regions of the femur, including the femoral head, was investigated using positron emission tomography (PET).MethodsThe subjects of this study consisted of 8 hip joints of four healthy male adults and 3 hip joints on the contralateral side of a femoral neck fracture, avulsion fracture of the greater trochanter and coxarthrosis (1 case each, all females) for a total of 11 hip joints of 7 subjects. The ages of the subjects ranged from 25 to 87 years (average age: 54 years). Blood flow was measured by means of the H215O dynamic study method and blood volume was measured by means of the15O-labeled carbon monoxide bolus inhalation method.ResultsBlood flow was determined to be 9.1 ± 4.8 ml/min/100 g in the ilium and among proximal regions of the femur (femoral head, neck and intertrochanteric region), 1.8 ± 0.7 ml/min/100 g in the femoral head, 2.1 ± 0.6 ml/min/100 g in the femoral neck, and 2.6 ± 0.7 ml/min/100 g in the intertrochanteric region. In addition, blood volume was 4.7 ± 1.3 ml/100 g in the ilium, and among proximal regions of the femur, 1.1 ± 0.5 m//100 g in the femoral head, 2.1 ± 0.7 ml/100 g in the femoral neck, and 2.6 ± 0.9 ml/100 g in the intertrochanteric region. The results showed that both blood flow and volume were lowest in the femoral head. Blood flow and volume were significantly lower in the proximal regions of the femur (femoral head, neck and intertrochanteric region) than in the ilium (p < 0.01).ConclusionThe present study demonstrated that the femoral head is in a hypoemic state as compared with other osseous tissue, indicating that even the slightest exacerbation of hemodynamics in the femoral head can trigger an ischemic condition culminating in ONF.

Hemobilia and cystic artery stump pseudoaneurysm associated with liver abscess after a laparoscopic cholecystectomy: report of a case.

A 63-year-old woman was admitted for cholecystitis and underwent a laparoscopic cholecystectomy (LC). She experienced abdominal pain and hemobilia 11 days after the LC. Angiography was performed but it did not show any source of bleeding. Thereafter, at 27 days after LC, a repeat angiogram was performed which revealed a pseudoaneurysm (PA) arising from a cystic artery stump and an embolized PA sack. However, another PA arising from near the embolized PA and liver abscess was observed 4 days after embolization. The arterial collateral flow was evaluated by endovascular balloon occlusion of the right hepatic artery and it was embolized proximal and distal to the bleeding point. The embolization of the partial hepatic artery was effective for PA when packing the PA sack proved to be insufficient. In patients with liver cirrhosis or liver abscess who require an adequate arterial liver flow, it is important to evaluate the collateral arterial flow before hepatic artery embolization.

Reliability of one-point blood sampling method for calculating input function in Na18F PET.

ObjectiveConventional methods of quantitative Na18F positron emission tomography require multiple arterial blood sampling in order to obtain the input function, and the procedures are invasive and complicated. This study aims to establish a simplified and reliable technique for obtaining the input function. MethodsMultiple arterial blood sampling was performed on 12 persons. The time point for one-point sampling was determined as the time when (1) the plasma radioactivity obtained showed the highest correlation to the real integrated value, which was calculated from the input function, and (2) the coefficient of variation of the real integrated value divided by plasma radioactivity obtained at each time point became the minimum. Scaling factors were obtained in order to estimate the plasma radioactivity at each time point, and a reference table was produced in order to estimate the input function. ResultsThe optimal timing for one-point sampling was 12 min after intravenous injection of Na18F. The estimated integrated value obtained from arterial blood sampling at 12 min and the reference table was highly correlated with the real integrated value (P<0.001). Levels of plasma radioactivity of arterial blood and venous blood were almost the same at 12 and 40 min after Na18F injection. Percentage errors in the estimation of the integrated value were 2.63% (n=12) for the arterial blood collected at 12 min and 4.14% (n=12) for the venous blood collected at 30 min. ConclusionsThis simplified method is clinically applicable and would replace traditional methods that require multiple blood sampling.

Progressive endoscopic findings in a case of aortoesophageal fistula

Aortoesophageal fistula (AEF) formation involves aortic disease with secondary rupture of a descending thoracic aortic aneurysm into the esophagus. Steffes and O’Leary reported that in approximately 80% of cases, massive fatal hemorrhage occurs within 1 week after onset of repeated transitory bleeding from an AEF. Although endoscopy should always be the first diagnostic modality, the sensitivity of endoscopy for detecting AEF is only 38%. A 76-year-old man was admitted to our hospital for mid-thoracic pain and dysphagia, and underwent endoscopy and computed tomography (CT). Endoscopy revealed an ulcerated extrinsic mass compressing the mid-esophagus, covered by a whitish thrombus but with no active bleeding (Fig. 1).The submucosal mass was pulsatile in the area surrounding the thrombus. Thoracic CT demonstrated a descending aortic pseudoaneurysm that compressed the mid-esophagus, and the patient was diagnosed with an AEF caused by a descending aortic pseudoaneurysm. Despite our recommendations, the patient refused intervention. Two days later, he was re-admitted following the abrupt onset of hematemesis. A second endoscopy showed the ulcerative lesion to be covered with adherent fresh blood clots (Fig. 2). A plain CT showed retention of fresh blood in the esophagus, and a contrast-enhanced CT revealed a penetrating atherosclerotic ulcer around the aortic pseudoaneurysm. The patient underwent emergency surgical intervention, and made a satisfactory recovery. Surgery revealed thrombus adhesion on the descending aorta, identifying the likely site of aortic damage and subsequent rupture into the esophagus. The whitish thrombus identified on the initial endoscopy was replaced by fresh blood clots over the ulcerative lesion 2 days later.The images included here capture the progressive endoscopic findings of untreated AEF, and also highlight the need for urgent intervention when AEF is detected.

Development of a novel fusion imaging technique in the diagnosis of hepatobiliary-pancreatic lesions.

Multi‐row detector computed tomography (MDCT) and magnetic resonance cholangiopancreatography (MRCP) play an important role in the imaging diagnosis of hepatobiliary‐pancreatic lesions. Here we investigated whether unifying the MDCT and MRCP images onto the same screen using fusion imaging could overcome the limitations of each technique, while still maintaining their benefits. Moreover, because reports of fusion imaging using MDCT and MRCP are rare, we assessed the benefits and limitations of this method for its potential application in a clinical setting.