Preoperative graft volume assessment with 3D-CT volumetry in living-donor lobar lung transplantations.

To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them. We calculated the volume ratio in 52 donors and tested the difference between the segmental volume ratios with a one-tailed t-test. We also calculated the predicted graft FVC in 21 LDLLTs using the segmental ratio pFVC(c) and the volume ratio pFVC(v), and then found the Pearson's correlation coefficients for both pFVC(c) and pFVC(v) with the recipients' actual FVC (rFVC) measured spirometrically 6 months after surgery. Significant differences were found between the segmental ratio and the average volume ratio for both sides (right, p＝0.03;left, p＝0.0003). Both pFVC(c) and pFVC(v) correlated significantly with rFVC at 6 months after surgery (p＝0.007 and 0.006). Both the conventional and the volumetric methods provided FVC predictions that correlated significantly with measured postoperative FVC.

A new phantom using polyethylene glycol as an apparent diffusion coefficient standard for MR imaging.

In recent years, magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has seen wide clinical use, such as for early detection of cerebrovascular diseases and whole body screening for tumors. The apparent diffusion coefficient (ADC) standard phantom, which mimics the ADC values of several lesions in the body, is indispensable for the development of new pulse sequences for DWI, such as diffusion-weighted whole-body imaging with background body-signal suppression (DWIBS). However, information on the ADC values of the previously reported ADC standard phantoms is limited, because these phantoms were made using only a few different materials at a limited range of concentrations, and the ADC values were measured only at certain temperatures. It has been considered difficult, if not impossible, to create a phantom that provides arbitrary ADC values, because it is difficult to calculate the concentrations of the materials and the temperature at ADC measurement. In this study, we used polyethylene glycol (PEG) as a phantom material, and developed an empirical formula to calculate the PEG concentration at any measurement temperature to obtain arbitrary ADC values of the phantom. DWI images of phantoms made using seven different PEG concentrations were taken under heating from 17 to 46 degrees C at 1 degrees C intervals. Using ADC values calculated from these DWI images, we developed two empirical formulas: i) an empirical formula to calculate the ADC values of phantoms made using any PEG concentration at any measurement temperature; and ii) an empirical formula to calculate PEG concentrations to obtain arbitrary ADC values at any measurement temperature. We inspected the accuracy of these empirical formulas by newly made PEG phantoms. A comparison between the ADC values calculated with the empirical formulas and the measured ADC values confirmed the high accuracy of these formulas. PEG phantoms are safe, inexpensive and easy to make, compared with the previously reported ADC standard phantoms. Our empirical formulas enable us to calculate PEG concentrations that provide arbitrary ADC values at any measurement temperature. The empirical formulas could be used within a range of ADC values from 0.37x10(-3) to 3.67x10(-3) mm(2)/s, PEG concentrations from 0 to 120 mM, and measurement temperatures from 18 to 45 degrees C. Using these formulas, it would be possible to make standard phantoms that mimic the ADC values of any clinical lesions. The PEG phantom might thus be an excellent new ADC standard phantom for MRI with DWI.

In vitro experimental study of the relationship between the apparent diffusion coefficient and changes in cellularity and cell morphology.

Diffusion-weighted magnetic resonance imaging (MRI) is frequently used clinically, and is available for the whole-body screening for tumors. The exact mechanism by which the apparent diffusion coefficient (ADC) value decreases in tumorous tissue remains unclear, although various theories have been proposed, including intracellular and extracellular factor theories. It is impossible to distinguish each factor in the intracellular and extracellular spaces as the source of MR signal generation by means of conventional comparison between MR images and pathological specimens. Other factors which have been reported to affect ADC include cellularity and cellular edema of human tissues, and temperature of phantoms at the time of measurement. We employed a new technique that enables cellular MR imaging using a newly developed bio-phantom containing a living culture tumor cell line, Jurkat-N1. We investigated possible reasons for observed decreases in ADC values for tumors, and we considered the contribution of both the intracellular and extracellular space to such a decrease. The ADC values of the bio-phantom increased with increasing heat exposure from 27 to 45 degrees C. ADC values also increased after the destruction by sonication of tumor cell membranes. ADC values decreased as cellularity increased in the bio-phantom. ADC values decreased due to cellular edema caused by a low salt concentration in the bio-phantom. Changes in pressure in the bio-phantom had no effect on the observed ADC values. We calculated both the intracellular ADC and extracellular ADC values using the ADC values, cellularity, and cellular volume of Jurkat-N1 cells in the bio-phantom. The extracellular ADC values in the bio-phantom were estimated to be lower than the ADC value of distilled water. These results indicate that not only intracellular ADC values, but also extracellular ADC values contribute to the determination of the ADC values of bio-phantoms. This is the first report to have examined the contribution of intracellular and extracellular space on the ADC values of bio-phantoms containing cultured tumor cells.

Gastric diverticulum simulating left adrenal incidentaloma in a hypertensive patient.

A 46-year-old Japanese male with hypertension was referred for examination of left adrenal tumor incidentally detected by computed tomography (CT) scan. The patient had a 4-month history of hypertension. Abdominal CT demonstrated a low-density mass 2.5 cm in diameter in the left adrenal region that was observed as a high-intense lesion with T2-weighted magnetic resonance imaging. (131) I-adosterol scintigraphy showed normal uptake of bilateral adrenals. The adrenocortical hormone levels were within normal ranges; however, urinary noradrenaline excretion was slightly elevated, likely due to concurrent sleep apnea syndrome. Based on the observation of a very tiny bubble in the ventral portion of the adrenal mass by careful review of CT images examined at a previous hospital, a restudy of abdominal CT with oral contrast was performed. In this restudy abdominal CT we observed positive enhancement of the left adrenal mass, indicating that the adrenal mass was a diverticulum derived from posterior gastric fornix. The present case study reinforces that preoperative differentiation from mimic adrenal tumors is necessary in cases of cystic adrenal mass in the left adrenal region.

Evaluation of esophageal varices by multidetector-row CT: correlation with endoscopic 'red color sign'.

To evaluate the ability of multidetector-row CT (MDCT) to predict a risk of hemorrhage in patients with esophageal varices, a total of 40 MDCT scans were performed in 29 patients who had been diagnosed with esophageal varices by conventional upper gastrointestinal tract endoscopy. In 11 patients, MDCT was performed both before and after endoscopic injection sclerotherapy (EIS). Endoscopically, the red color sign (RC sign) was present in 28 scans. Of the 11 patients who underwent EIS, the RC sign disappeared after EIS in 9. The MDCT scans were obtained in the arterial, portal, and equilibrial phases, and the portal phase images were used in this study. Subsequently, the extent of esophageal varices was categorized into four MDCT scores. The variceal score, the maximum short axis of the varices, and the presence of palisade vein dilatation obtained from MDCT had significant correlation with endoscopic variceal forms, and the presence and severity of RC sign, respectively (p<0.01). All cases with a maximum minor axis of more than 4 mm showed positive RC sign. MDCT was useful in the evaluation of esophageal varices for predicting a risk of hemorrhage.

Cerebral perfusion MR imaging using FAIR-HASTE in chronic carotid occlusive disease: comparison with dynamic susceptibility contrast-perfusion MR imaging.

To determine the efficacy of flow-sensitive alternating inversion recovery using half-Fourier single-shot turbo spin-echo (FAIR-HASTE) in detecting cerebral hypoperfusion in chronic carotid occlusive disease, we subjected 12 patients with various degrees of cervical internal carotid artery stenoses and/or occlusion (Stenosis group) and 24 volunteers (Normal group) to FAIR-HASTE. In addition, 10 out of 12 patients in the Stenosis group underwent dynamic susceptibility contrast-perfusion magnetic resonance imaging (DSC-pMRI) before and after revascularization in the dominantly affected side. The absolute asymmetry indexes (AIs) of both cerebral hemispheres in the Normal and Stenosis groups were compared in FAIR-HASTE. In addition, the AIs were compared with those in the Stenosis group before and after revascularization in both FAIR-HASTE and regional cerebral blood flow (rCBF), calculated with DSC-pMRI. A statistically significant difference was recognized between the AIs in the Normal and Stenosis groups (AI = 2.25 +- 1.92, 8.09 +- 4.60, respectively ; p < 0.0001). Furthermore, in the Stenosis group the AIs on both FAIR-HASTE (8.88 +- 4.93, 2.22 +- 1.79, respectively ; p = 0.0003) and rCBF (7.13 +- 3.57, 1.25 +- 1.33, respectively ; p = 0.0003) significantly decreased after revascularization. In the Stenosis group, before revascularization, signal intensity on both FAIR-HASTE and rCBF had a tendency to be lower in the dominantly affected side. FAIR-HASTE imaging was useful in the detection and evaluation of cerebral hypoperfusion in chronic occlusive carotid disease.

Manifestation of rheumatoid arthritis after transsphenoidal surgery in a patient with acromegaly.

Acromegalic arthropathy is one of the most frequent manifestations occurring in acromegaly patients. In contrast, rheumatoid arthritis (RA) is a rare clinical complication in acromegaly patients. Here, we report a 70-year-old Japanese woman with acromegaly, who complained of bilateral finger stiffness and polyarthralgia two months after transsphenoidal surgery of a growth hormone (GH)-secreting pituitary adenoma. Postoperative levels of serum GH and insulin-like growth factor-1 (IGF-1) were markedly decreased without any secretory deficiency of other anterior pituitary hormones. Hand X-ray did not show typical RA changes; however, erosive changes in carpal bones were clearly detected by magnetic resonance imaging with gadolinium enhancement. Based on the levels of serological markers in the patient following surgery including C-reactive protein, rheumatoid factor and matrix metalloproteinase-3, anti-rheumatic therapy was subsequently commenced. Regardless of the levels of GH and IGF-1, acromegaly patients frequently complain about joint-related symptoms even after remission. Therefore, careful observation of bone erosive changes and immunological activity in acromegaly patients is required when joint-related symptoms persist.

Differential diagnosis of adrenal masses by chemical shift and dynamic gadolinium enhanced MR imaging.

Chemical shift MRI is widely used for identifying adenomas, but it is not a perfect method. We determined whether combined dynamic MRI methods can lead to improved diagnostic accuracy. Fifty-seven adrenal masses were examined by chemical shift and dynamic MR imaging using 2 MR systems. The masses included 38 adenomas and 19 non-adenomas. In chemical shift MRI studies, the signal intensity index (SI) was calculated, and the lesions classified into 5 types in the dynamic MRI studies. Of the 38 adenomas studied, 37 had an SI greater than 0. In the dynamic MRI, 34 of 38 adenomas showed a benign pattern (type 1). If the SI for the adenomas in the chemical shift MRI was considered to be greater than 0, the positive predictive value was 0.9, and the negative predictive value was 0.94 and kappa = 0.79. If type 1 was considered to indicate adenomas in the dynamic MRI, the corresponding values were 0.94, 0.81 and kappa = 0.77 respectively. The results obtained when the 2 methods were combined were 1, 0.95 and kappa = 0.96 respectively. The chemical shift MRI was found to be useful for identifying adenomas in most cases. If the adrenal mass had a low SI (0 < SI < 5), dynamic MRI was also found to be helpful for making a differential diagnosis.

MR imaging of vertebral metastases at 0.2 Tesla: clinical evaluation of T1-weighted opposed-phase gradient-echo imaging.

The purpose of this study was to evaluate clinically T1-weighted spin-echo imaging (T1-SE) and T1-weighted opposed-phase gradient-echo (T1-opposed GRE) in medical examinations for vertebral metastases using 0.2 Tesla MRI. Twenty-one patients (9 males and 12 females, 105 vertebrae) with non-neoplastic lesions were assigned to the normal group (Group N), whereas 27 patients (16 males and 11 females, 133 vertebrae) with malignant metastatic vertebral lesions were assigned to the metastatic group (Group M). Using quantitative analysis, the contrast to noise ratio (CNR) for bone marrow to muscle in the region of interest (ROI) defined by the operator were determined with both groups, whereas the CNR for lesion to bone marrow was determined with Group M. In the subjective analysis, 275 vertebrae of 27 patients in Group M were evaluated. There were significant differences in the Group M between CNR values, T1-SE and T1-opposed GRE. The evaluation by T1-SE image alone was rated as 85.0% for sensitivity, 99.3% for specificity, respectively. On the other hand, evaluation rate only by T1-opposed GRE was 98.5% for sensitivity, 82.4% for specificity, respectively. T1-opposed GRE image is an effective tool for 0.2 Tesla MRI to examine metastatic bone marrow tumors. These findings indicate the necessity of both T1-SE and T1-opposed GRE in diagnostic imaging of vertebral metastases using 0.2 Tesla MRI.