Takuro Horikoshi

What is the origin of intravascular gas on postmortem computed tomography

PURPOSE Intravascular gas is frequently demonstrated on postmortem computed tomography (PMCT). The purpose of this study is to classify the distribution patterns of intravascular gas and to determine its developmental mechanism. METHOD AND MATERIALS The series included 43 cases (mean age, 62 years). All causes of death were non-traumatic (14 cases, sudden death; 29 cases, death caused by known disease). Using a 16-row multi-detector CT, whole body images were obtained with 1.25-mm collimation. Gas in veins, right heart was classified as venous gas. Gas in arteries, left heart was classified as arterial gas. RESULTS PMCT showed intravascular gas in 20 cases. Distribution of gas was divided into 2 patterns; pattern 1 (11 cases): a small volume of venous gas (superior and inferior vena cava, right heart, subclavian veins and brachiocephalic veins) and no arterial gas; pattern 2 (9 cases): both venous (same positions of pattern 1 plus hepatic veins) and arterial gas (left heart, ascending aorta, vertebral arteries and cerebral arteries). CONCLUSION Since imaging findings of pattern 1 are similar to those frequently demonstrated after intravenous contrast-enhanced CT, this gas is presumed to be of exogenous origin from intravenous catheters. In contrast, the gas in pattern 2 may be of endogenous origin, such as decompression disease. Bubbles should move through the ventral side of vessels in the supine position, and subsequently must be trapped by extruded anatomical structures to the ventral side, for example, right ventricle, vertebral and cerebral arteries, hepatic veins and renal veins.

Dual-time point scanning of integrated FDG PET/CT for the evaluation of mediastinal and hilar lymph nodes in non-small cell lung cancer diagnosed as operable by contrast-enhanced CT

PURPOSE To evaluate whether dual-time point scanning with integrated fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography and computed tomography (PET/CT) is useful for evaluation of mediastinal and hilar lymph nodes in non-small cell lung cancer diagnosed as operable by contrast-enhanced CT. MATERIALS AND METHODS PET/CT data and pathological findings of 560 nodal stations in 129 patients with pathologically proven non-small cell lung cancer diagnosed as operable by contrast-enhanced CT were reviewed retrospectively. Standardized uptake values (SUVs) on early scans (SUVe) 1h, and on delayed scans (SUVd) 2h after FDG injection of each nodal station were measured. Retention index (RI) (%) was calculated by subtracting SUVe from SUVd and dividing by SUVe. Logistic regression analysis was performed with seven kinds of models, consisting of (1) SUVe, (2) SUVd, (3) RI, (4) SUVe and SUVd, (5) SUVe and RI, (6) SUVd and RI, and (7) SUVe, SUVd and RI. The seven derived models were compared by receiver-operating characteristic (ROC) analysis. k-Fold cross-validation was performed with k values of 5 and 10. p<0.05 was considered statistically significant. RESULTS Model (1) including the term of SUVe showed the largest area under the ROC curve among the seven models. The cut-off probability of metastasis of 3.5% with SUVe of 2.5 revealed a sensitivity of 78% and a specificity of 81% on ROC analysis, and approximately 60% and 80% on k-fold cross-validation. CONCLUSION Single scanning of PET/CT is sufficiently useful for evaluating mediastinal and hilar nodes for metastasis.

Initial experience of radiotherapy plus cetuximab for Japanese head and neck cancer patients

In Japan, cetuximab with concurrent bioradiotherapy (BRT) for squamous cell carcinoma of head and neck (SCCHN) was approved in December 2012. We herein report our initial experience of BRT, with special emphasis on acute toxicities of this combination therapy. Thirty-one non-metastatic SCCHN patients who underwent BRT using cetuximab between July 2013 and June 2014 were retrospectively evaluated. All patients received cetuximab with a loading dose of 400 mg/m2 one week before the start of radiotherapy, followed by 250 mg/m2 per week during radiotherapy. The median cycle of cetuximab was seven cycles and the median dose of radiotherapy was 70 Gy. Twenty-five patients (80.6%) accomplished planned radiotherapy and six cycles or more cetuximab administration. Six patients (19.4%) discontinued cetuximab. Grade 3 dermatitis, mucositis and infusion reaction occurred in 19.4%, 48.3% and 3.2%, respectively. One patient experienced Grade 3 gastrointestinal bleeding caused by diverticular hemorrhage during BRT. Grade 3 drug-induced pneumonitis occurred in two patients. The response rate was 74%, including 55% with a complete response. BRT using cetuximab for Japanese patients with SCCHN was feasible as an alternative for cisplatin-based concurrent chemoradiation, although longer follow-up is necessary to evaluate late toxicities.

Applicability of facial soft tissue thickness measurements in 3-dimensionally reconstructed multidetector-row CT images for forensic anthropological examination

PURPOSE The purpose of this study is to assess the applicability of facial soft tissue measurements using 3-dimensional reconstructed MDCT and to compare the results with previously reported Japanese data. METHODS AND MATERIALS This study included 50 Japanese cadavers who underwent postmortem whole body 16-detector CT within 0-3 days after death. Using 3-D workstation, 10 anthropological measuring points were located and the soft tissue thicknesses were measured. The differences between the acquired thickness and the previously reported Japanese average thickness were statistically analyzed. RESULTS All measuring points were readily determined on the 3-dimensional reconstructed images. Previous Japanese cadaveric data was thinner than our data in almost all sites except for 1 measuring point (mid-philtrum). Previous living Japanese data was thicker than ours except for 1 measuring point (end of nasal). CONCLUSION Facial soft tissue thickness was easily assessed using 3-D reconstructed MDCT images. At many measuring points, our results were thicker than previously reported cadaveric data and were thinner than the data from live persons.

Can ruptured abdominal aortic aneurysm be accurately diagnosed as the cause of death without postmortem computed tomography when autopsies cannot be performed

PURPOSE This study aimed to conduct a multicentre retrospective review of cases to clarify how many ruptured abdominal aortic aneurysms (RAAAs) as the cause of death could be diagnosed without post-mortem computed tomography (PMCT) when autopsies cannot be performed. METHODS We collected consecutive PMCT data from January 2002 to December 2009 from three institutes where PMCT examinations are performed on a routine basis for deceased patients with unknown causes of death. A total of 19 cases were identified where PMCT revealed RAAAs. Ante-mortem clinical presentations, post-mortem external examinations, and peri-mortem ultrasonography findings were assessed for their diagnostic accuracy. RESULTS The correct diagnosis based on the classic triad of shock, acute abdominal pain, and pulsatile abdominal mass was made in only one of 19 (5.3%) patients. Shock, acute abdominal pain, and abdominal swelling were found in five of 19 (26%) patients. Shock and acute abdominal pain or abdominal swelling were found in two of 19 (10%) patients. Ten of 19 (53%) patients only had shock. Peri-mortem ultrasonography was performed in seven of 19 patients; one was diagnosed with RAAA (14%). No patients had pre-mortem CT examinations. CONCLUSIONS Post-mortem diagnosis of RAAA is difficult to make based on ante-mortem clinical presentation, post-mortem external examinations, or peri-mortem ultrasonography. PMCT is recommended for diagnosing RAAA as the cause of death if pre-mortem CT examinations are not carried out when autopsies cannot be performed.

The incidence and significance of retropharyngeal lymph node metastases in hypopharyngeal cancer.

OBJECTIVE To evaluate the incidence and clinical significance of retropharyngeal lymph node metastasis in hypopharyngeal cancer. METHODS Pretreatment computed tomography and/or magnetic resonance images of 152 patients treated between 1998 and 2009 were retrospectively reviewed. The prognostic significance of retropharyngeal lymph node metastasis for 116 patients who received definitive treatment was also analyzed. RESULTS Twelve patients (8%) were radiologically positive for retropharyngeal lymph node metastasis. Tumors originating from the posterior wall showed significantly higher incidence of retropharyngeal lymph node than those originating from other sites (23.8 vs. 5.3%, P = 0.01). The majority of patients with retropharyngeal lymph node involvement experienced distant metastasis. The overall survival rate of patients with retropharyngeal lymph node metastasis was worse than in those lacking retropharyngeal lymph node involvement (0 vs. 68.8% at 2 years, P < 0.01), and so was the cause-specific survival rate (0 vs. 74% at 2 years, P < 0.01). CONCLUSIONS Patients with hypopharyngeal cancer, especially those with posterior wall tumors, are at high risk for retropharyngeal lymph node involvement. Patients with retropharyngeal lymph node metastasis developed distant metastasis frequently, and showed dismal outcomes.

Computed tomography is important in appropriately diagnosing patients with third-degree atrioventricular block and second-degree atrioventricular block but not Wenckebach type.

PURPOSE To evaluate CT utility for detection of cardiac or lung abnormalities in the diagnosis of organic cardiac disease in subjects with second- or third-degree atrioventricular block (AVB) excepting Wenckebach type. MATERIALS AND METHODS A total of 50 consecutive patients (25 male; 64±15years) with de novo third- or second-degree AVB underwent both TTE and a combination of cardiac and chest 320 slice CT (Aquilion one, Toshiba Medical) and were retrospectively analyzed. The presence of focal left ventricular (LV) wall thinning and thickening was evaluated on both TTE and cardiac CT. We evaluated the presence of significant coronary artery stenosis, focal late enhancement (LE) in LV myocardium, significant-sized (>10mm) lymph nodes in hialus or mediastinum and/or typical lung nodules for sarcoidosis on CT. RESULTS Abnormalities for 26%, 30%, and 36% of patients were demonstrated on TTE, cardiac CT, and a combination of cardiac and chest CT, respectively. 12% and 18% patients who did not exhibit cardiac abnormalities on TTE, revealed abnormalities on cardiac CT, or a combination of cardiac and chest CT, respectively. 36% patients had organic cardiac diseases. Sensitivities for detection of organic cardiac disease were significantly greater when cardiac and chest CT were combined than TTE alone (P<0.01). CONCLUSIONS Approximately one third of patients with third- or second-degree AVB had organic cardiac diseases. For detection of cardiac and chest abnormality and correct diagnosis of organic cardiac disease in patients with third- or second-degree AVB, TTE is not sufficient on its own. CT or a combination of TTE and CT are required.

Traumatic axonal injury revealed by postmortem magnetic resonance imaging: A case report

In forensic investigations, it is important to detect traumatic axonal injuries (TAIs) to reveal head trauma that might otherwise remain occult. These lesions are subtle and frequently ambiguous on macroscopic evaluations. We present a case of TAI revealed by pre-autopsy postmortem magnetic resonance imaging (PMMR). A man in his sixties was rendered unconscious in a motor vehicle accident. CT scans revealed traumatic mild subarachnoid hemorrhage. Two weeks after the accident he regained consciousness, but displayed an altered mental state. Seven weeks after the accident, he suddenly died in hospital. Postmortem computed tomography (PMCT) and PMMR were followed by a forensic autopsy. PMMR showed low-intensity lesions in parasagittal white matter, deep white matter, and corpus callosum on three-dimensional gradient-echo T1-weighted imaging (3D-GRE T1WI). In some of these lesions, T2∗-weighted imaging also showed low-intensity foci suggesting hemorrhagic axonal injury. The lesions were difficult to find on PMCT and macroscopic evaluation, but were visible on antemortem MRI and confirmed as TAIs on histopathology. From this case, it can be said that PMMR can detect subtle TAIs missed by PMCT and macroscopic evaluation. Hence, pre-autopsy PMMR scanning could be useful for identifying TAIs during forensic investigations.

Risk factors of ineffective drainage in uncovered self-expandable metal stenting for unresectable malignant hilar biliary strictures

Aim In this study, we assessed the factors contributing to ineffective drainage in the initial transpapillary uncovered self-expandable metal stent (USEMS) placements in patients with unresectable malignant hilar biliary strictures (UMHBSs) (Bismuth type II or higher). Methods This was a retrospective, single-center study. A total of 97 patients with UMHBSs who underwent technically successful initial USEMS placements using endoscopic retrograde cholangiopancreatography (ERCP) were classified into the effective drainage group (n = 73) or the ineffective drainage group (n = 24). We then compared group characteristics, clinical outcomes, and drained liver volumes. Drained liver volume was measured by using computed tomography volumetry. The definition of effective biliary drainage was a 50% decrease in the serum total bilirubin level or normalization of the level within 14 days of stent placement. Results Univariate analysis showed that ineffective drainage was associated with the pre-ERCP serum total bilirubin level (P = 0.0075), pre-ERCP serum albumin level (P = 0.042), comorbid liver cirrhosis (P = 0.010), drained liver volume (P = 0.0010), and single stenting (P = 0.022). Multivariate analysis identified comorbid liver cirrhosis (adjusted odds ratio [OR], 5.79; 95% confidence interval [CI], 1.30–25.85; P = 0.022) and drained liver volume < 50% (adjusted OR, 5.50; 95% CI, 1.50–20.25; P = 0.010) as independent risk factors of ineffective drainage. Conclusion Comorbid liver cirrhosis and a drained liver volume < 50% contributed significantly to ineffective drainage in the initial transpapillary USEMS placements for UMHBSs.

Biparametric Prostate Imaging Reporting and Data System version2 and International Society of Urological Pathology Grade Predict Biochemical Recurrence after Radical Prostatectomy

Micro‐Abstract We found that Prostate Imaging Reporting and Data System (PI‐RADS), version 2 and International Society of Urological Pathology (ISUP) grade predict for biochemical recurrence after radical prostatectomy. Based on the score of 2 factors, we created a risk classification. The poor‐risk group had significantly worse prognosis compared with that of intermediate‐ to favorable‐risk groups. This is the first report to show the value of combining PI‐RADS and ISUP grade for predicting the prognosis of radical prostatectomy patients. Background: We retrospectively assessed the clinical significance of the Prostate Imaging Reporting and Data System (PI‐RADS), version 2, criteria based on biparametric magnetic resonance imaging (bp‐MRI), together with the International Society of Urological Pathology (ISUP) grade, for predicting biochemical recurrence (BCR) after radical prostatectomy. Materials and Methods: The data from 126 patients who had undergone radical prostatectomy were retrospectively analyzed. The prognostic significance of the PI‐RADS v2 score based on bp‐MRI was assessed with other clinical factors, including the ISUP grade. We defined a positive PI‐RADS and ISUP score as ≥ 4 and ≥ 3, respectively. Statistical analysis was performed using Cox proportional hazard models, logistic regression analysis, and the Kaplan‐Meier method. Results: The median age and median prostate‐specific antigen level were 66 years and 7.96 ng/mL, respectively. The number of positive PI‐RADS scores was 106 (84.1%) and the number of positive ISUP grade scores was 71 (56.3%). PI‐RADS ≥ 4 (P = .0031) and ISUP ≥ 3 (P = .070) were the 2 independent prognostic factors predictive of BCR. A positive PI‐RADS score was related to tumor volume (P = .014), and a positive ISUP score was related to prostate‐specific antigen level (P = .043), extraprostatic extension (P = .029), and Gleason upgrading (P < .0001). After stratifying patients into risk groups according to PI‐RADS and ISUP positivity, the poor‐risk group (PI‐RADS and ISUP grade positive) showed significantly worse BCR‐free survival compared with that of the favorable‐ and intermediate‐risk groups (P < .0001), with a median survival difference of 21 months. Conclusion: Biparametric PI‐RADS v2 and ISUP grade criteria predicted for BCR after radical prostatectomy. PI‐RADS v2 combined with the ISUP grade might be helpful in choosing the treatment modality of patients with localized prostate cancer.