MR Imaging with Apparent Diffusion Coefficient Histogram Analysis: Evaluation of Locally Advanced Rectal Cancer after Chemotherapy and Radiation Therapy.

Purpose To determine response to neoadjuvant chemotherapy and radiation therapy in patients with locally advanced rectal cancer (LARC) by using magnetic resonance (MR) apparent diffusion coefficient (ADC) histogram analysis. Materials and Methods Ninety-two patients with LARC underwent MR imaging with rectal barium before and after chemotherapy and radiation therapy (CRT). Rectal expansion with barium expanded the lumen, provided similar imaging geometry before and after CRT, and eliminated fecal matter, air, and residual fluid. T2-weighted images, the percentage change in ADC, and ADC histogram skewness and kurtosis were assessed. The histopathologic tumor regression grade (TRG) ranged from 1a (66%-99% residual tumor cells) to 3 (no residual cells). The Wilcoxon signed-rank test, the Spearman correlation test, multivariable linear regression, and one-way analysis of variance were used to determine post- and pretreatment differences and correlations between tumor size and ADC. Results Of the 92 patients, 16 (17.4%) had TRG 3, 27 (29.3%) had TRG 2b, 24 (26.1%) had TRG 2a, 14 (15.2%) had TRG 1b, and 11 (12%) had TRG 1a. Post-CRT skewness (regression coefficient = 10.9, P = .06) and percentage ADC change (regression coefficient = -0.18, P = .03) were associated with the percentage of residual tumor. Post-CRT skewness and percentage ADC change, respectively, showed negative and positive correlation with histopathologic TRG (post-CRT skewness: P = .024; percentage ADC change: P = .001). Conclusion In patients with LARC, post-CRT skewness of the ADC histogram and percentage change in ADC were useful for predicting a favorable response to neoadjuvant CRT. © RSNA, 2018 Online supplemental material is available for this article.

Phase II study of preoperative concurrent chemoradiotherapy with S-1 plus bevacizumab for locally advanced resectable rectal adenocarcinoma.

OBJECTIVE: A single-arm phase II clinical trial was conducted to evaluate the safety and efficacy of preoperative chemoradiotherapy (CRT) with concurrent S-1, bevacizumab, and radiation in patients with locally advanced rectal cancer (LARC). METHODS: Fifty-two patients with LARC were enrolled. A total dose of 45 Gy was delivered in 25 fractions over 5 weeks, S-1 was administered orally twice a day on days 1-14 and 22-35, and bevacizumab was administered on days 1, 15, and 29. Surgical resection was scheduled 8 weeks (6-10 weeks) after completing the CRT. RESULTS: All 52 patients underwent R0 radical surgery. Sphincter preservation was possible in 38 (73.1%) patients. A pathologic complete response was obtained in 10 (19.2%) patients, a pathologic downstaging was achieved in 37 (71.2%) patients, and the tumor shrinkage rate was 77.1%. The only grade 3 adverse events were leukopenia and rash in 1 (1.9%) patient. The rate of postoperative complications was 28.8%. Anastomotic leakage occurred in 9 (23.7%) of the 38 patients who underwent sphincter-preserving surgery. Perineal wound dehiscence developed in 2 (14.3%) of the 14 patients who received an abdominoperineal resection. CONCLUSIONS: Adding bevacizumab to S-1 clearly increased the incidence of wound-related complications, with no distinct enhancement of tumor response.

Predictive markers of chemoradiotherapy for rectal cancer: comparison of biopsy specimens taken before and about 1 week after the start of chemoradiotherapy.

BACKGROUND: Preoperative chemoradiotherapy (CRT) significantly decreases local recurrence in patients with rectal cancer. Although various biomarkers in biopsy specimens obtained before starting CRT have been examined, reliable prognostic factors have yet to be established. We tested the hypothesis that biopsy specimens obtained soon after the start of CRT can be used as prognostic factors. METHODS: Preoperative CRT was given to 70 consecutive patients with rectal cancer. Biopsies were taken before and about 7 days after starting CRT. The specimens were stained with hematoxylin and eosin (HE), and the expressions of Ki67, p53, and p21 and apoptosis were evaluated immunohistochemically. RESULTS: The expressions of Ki67, p53, and p21 and apoptosis before treatment were not significantly related to histologic response or tumor shrinkage. In specimens obtained about 7 days after CRT began, marked histologic regression was significantly higher in p21-positive, apoptosis-positive cases, and in cases with moderate changes on HE specimens (p = 0.017, p = 0.010, and p = 0.004, respectively). The tumor shrinkage was significantly higher in apoptosis-positive cases and cases with moderate changes on HE specimens (p = 0.002 and p < 0.001, respectively). Disease-free survival (DFS) was significantly higher in patients who had marked regression than in those who did not (p = 0.019). DFS was also significantly higher in patients with moderate changes on HE specimens than in those with mild changes (p = 0.016). CONCLUSIONS: Changes on HE-stained biopsy specimens obtained about 1 week after starting CRT are a reliable prognostic factor, similar to histologic marked regression in resected specimens; a major advantage is that the former results are available at an early phase.

Relationship between histologic response and the degree of tumor shrinkage after chemoradiotherapy in patients with locally advanced rectal cancer.

BACKGROUND: Preoperative chemoradiotherapy (CRT) significantly decreases local recurrence in advanced rectal cancer. We studied whether the degree of tumor shrinkage can be used as a predictor of histologic response. METHODS: The subjects were 114 patients with locally advanced rectal cancer who underwent total mesorectal excision after receiving radiotherapy combined with uracil/tegafur (UFT) or S-1. The degree of tumor shrinkage based on barium enema examination and magnetic resonance imaging (MRI) were assessed before CRT and immediately before surgery. RESULTS: A histologic complete response (ypCR), histologic marked regression, T and N downstaging were associated with significantly higher tumor-shrinkage rates on barium enema (P < 0.01, P < 0.01, P < 0.01, and P < 0.01, respectively) as well as on MRI (P < 0.01, P < 0.01, P < 0.01, and P = 0.01, respectively). On multivariate analysis, ypCR and histologic marked regression were significantly related only to tumor-shrinkage rates on barium enema (P < 0.01 and P < 0.01, respectively), and were not related to tumor-shrinkage rates on MRI. CONCLUSIONS: The degree of tumor shrinkage is closely related to the final histologic response. Two-dimensionally evaluated tumor-shrinkage rates based on barium enema are adequate for the prediction of histologic response.

Case of Isolated Absence of the Azygos Vein: Evaluation Using Photon-counting Detector CT.

The isolated absence of the azygos vein was incidentally found on computed tomography (CT) examination in a 60-year-old female. The exact anomaly can be evaluated on high-resolution images of 0.4-mm slice thickness with low keV using photon-counting detector CT. The azygos vein, including the azygos arch, was absent, and a mildly dilated hemiazygos vein flowed to the left brachiocephalic vein through the left superior intercostal vein. A hemiazygos vein connected the left renal vein at the level of the first lumbar vertebra. This patient was the second patient to undergo evaluation using volume rendering images. High-resolution maximum-intensity projection images were useful for assessing the anatomy. Radiation dose was decreased compared with that in conventional CT.

Study of the association between an anomalous superior vena cava and horseshoe kidney.

BACKGROUND: The incidence of inferior vena cava anomalies in patients with horseshoe kidney is higher than that reported in the general population. As far as we know, no studies have reported the incidence and variations of superior vena cava (SVC) anomalies using multidetector-row computed tomography (MDCT) in patients with horseshoe kidney. METHODS AND RESULTS: Using MDCT, 71 patients with a horseshoe kidney (group A: 45 males, 26 females; mean age, 60.1 ± 10.2 years) and 2,292 patients without a horseshoe kidney (group B: 1,385 males, 907 females; mean age, 61.1 ± 13.5 years) were retrospectively evaluated for the incidence and variations of SVC anomalies, and the incidence of an anomalous SVC was compared between groups. An anomalous SVC was identified in 3 group A patients (4.2%) (double SVC, n=2; persistent left SVC without a right SVC, n=1) and 5 group B patients (0.22%) (double SVC, n=3; persistent left SVC without a right SVC, n=2). MDCT revealed a significantly higher incidence of anomalous SVC in patients with a horseshoe kidney than in those without a horseshoe kidney (P<0.001). CONCLUSIONS: Patients with horseshoe kidney frequently have an anomalous SVC. Although the incidence of horseshoe kidney is related in some way to that of an anomalous SVC, the reasons for their coexistence remain unclear.

Major venous anomalies are frequently associated with horseshoe kidneys.

BACKGROUND: Several cases of horseshoe kidney with anomalous inferior vena cava (IVC) have been described, but there have been no reports of the incidence and variation of anomalous IVC in patients with horseshoe kidneys detected using multidetector row computed tomography (MDCT). METHODS AND RESULTS: 105 patients with horseshoe kidneys were evaluated with MDCT and a variety of venous anomalies were identified in 30 patients (28.6%). Anatomical variations of the renal vein were identified in 24 patients (22.9%), which was no higher than the reported incidence in the general population. However, variations of the IVC were identified in 6 patients (5.7%), which was a higher incidence than expected to be found in the general population: 1 pre-isthmic IVC with retrocaval ureter, 2 double IVCs posterior to the horseshoe kidney, 2 left IVCs posterior to the horseshoe kidney, and 1 azygos continuation of the IVC. CONCLUSIONS: Horseshoe kidneys are frequently found in patients with other venous, and particularly IVC, anomalies, which should be evaluated using MDCT as part of treatment planning.

A case of intrahepatic splenosis: usefulness of splenic scintigraphy.

We report a 39-year-old male with intrahepatic and peritoneal splenosis, focusing on scintigraphic findings. Dynamic computed tomography (CT) showed a 3 cm lesion in the posterior right lobe of the liver with strong early phase enhancement that was homogenous to the liver enhancement in the late phase. A few enhancing nodules were also found in the peritoneum. On gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced dynamic magnetic resonance imaging (MRI), the hepatic lesion had abnormal signal on diffusion-weighted imaging, high signal intensity on T2-weighted imaging, and early enhancement with accumulation decline in the hepatocyte phase. CT and MRI findings of the hepatic lesion were similar to normal spleen. To rule out hepatic neuroendocrine tumor and peritoneal metastases, somatostatin receptor scintigraphy was performed and showed tracer accumulation in the hepatic lesion, which we considered a false positive. Splenic scintigraphy using Tc-99 m-phytate showed accumulation in the hepatic lesion and peritoneal nodules. Given the patient's history of splenic injury and splenectomy 15 years prior and the current imaging findings, we highly suspected splenosis. After surgical treatment, the patient was pathologically diagnosed with intrahepatic and peritoneal splenosis. Splenosis should be suspected when a patient has a history of trauma or abdominal surgery. Since intrahepatic splenosis presents as a nonspecific hypervascular lesion on CT and MRI, splenic scintigraphy should be considered in these patients. In addition Tc-99 m-phytate scintigraphy is easy to use and cost-effective.

Optimal phase analysis of electrocardiogram-gated computed tomography angiography in patients with Stanford type A acute aortic dissection.

OBJECTIVE: To determine the phase that facilitates flap observation of the ascending aorta in Stanford type A acute aortic dissection with perfused false lumen. METHODS: We reconstructed retrospective Electrocardiogram-gated Computed Tomography Angiography images of the ascending aorta of all 20 patients to 20 phases of curved-multiplanar reconstruction in 5% increment. One radiologist created and randomized 10 cross-sectional images of each phase for every patient and two radiologists scored these images on a 5-point scale depending on the degree of flap stoppage. We calculated the average score for each phase of each case and compared them among the three groups. RESULTS: Image scores were significantly better in the 65 %-100 % R-R interval group than those in the 5%-30 % (p < 2e-16) and 35 %-60 % R-R interval groups(p = 7.2e-10). Similar scores were observed in the Heart Rate > 70 group (p = 0.00039, 2.2e-14). Moreover a similar tendency was observed in the arrhythmia group (p = 0.0035, 0.294). No difference was found in the degree of flap stoppage in the 65 %-100 % R-R interval group between the Heart Rate > 70 and Heart Rate ≤ 70 groups (p = 0.466) and between the arrhythmia and non-arrhythmia groups (p = 0.1240). CONCLUSION: In observing the ascending aorta, We obtained a good image at 65 %-100 % R-R interval and similar tendency was observed in the patients with arrhythmia.

Paravesical space arteriovenous malformation as a specific subgroup of pelvic vascular anomaly: a case series and review of literature.

Treatment of pelvic arteriovenous malformations (AVMs) is frequently challenging because of the complex structures and anatomical diversity among cases. We present a case series of six patients with pelvic AVMs. All patients had a similar anatomical structure consisting of multiple feeders from the unilateral internal iliac artery, collecting into a dilated venous sac in the unilateral paravesical space and draining into a single outflow, eventually joining the pre-prostatic vein or internal iliac vein. Five among these patients were successfully treated by catheter-directed embolo-sclerotherapy. In addition to our six cases, we identified six previous case reports of pelvic AVM with similar anatomical characteristics. Herein, we summarize the clinical and anatomical features of these 12 paravesical AVM cases. In all cases, the patients were men; the AVM was predominantly located at the right paravesical space and demonstrated good therapeutic effect of catheter-directed embolosclerotherapy. These paravesical AVMs may constitute a new subgroup of pelvic vascular anomalies with the same etiology that are treatable by adequate catheter intervention.

Hooking intestine sign: a typical diagnostic CT finding of Petersen's hernia.

PURPOSE: To clarify typical diagnostic computed tomography (CT) findings of Petersen's hernia for differentiation from other causes of internal hernia observed in patients having undergone gastrectomy with Roux-en-Y gastric bypass. METHODS: We retrospectively reviewed CT findings of internal hernia in patients who had undergone both gastrectomy and Roux-en-Y reconstruction and a second surgery for bowel obstruction. Thirteen patients with Petersen's hernia and 6 with internal hernia other than Petersen's hernia were investigated. Six CT findings, viz. whirl sign, mesenteric fat haziness, intestinal distension in the upper abdomen, herniated intestinal loop above the gastric level, middle/distal ileum courses downwards from the left hypochondrium, and hooking intestine sign, which means two or more intestines pass through the inner side of J-shaped vessels consisting of mesenteric vessels of the elevated jejunum, were scored and evaluated regarding their diagnostic performance. RESULTS: The hooking intestine sign showed the highest sensitivity, specificity and accuracy (100%, 100% and 100%). We could detect J-shaped vessels in all Petersen's hernia patients. Inside the J-shaped vessels there were two or more intestinal tracts passing through in the Petersen's hernia group. There was only transverse colon inside the J-shaped vessels in the control group. CONCLUSION: The hooking intestine sign may be useful for diagnosing Petersen's hernia on CT.

Congenital anomalies of the left brachiocephalic vein detected in adults on computed tomography.

PURPOSE: Anomalous left brachiocephalic vein (BCV) is a rare and less known systemic venous anomaly. We evaluated congenital anomalies of the left BCV in adults detected during computed tomography (CT) examinations. MATERIALS AND METHODS: This retrospective study included 81,425 patients without congenital heart disease who underwent chest CT. We reviewed the recorded reports and CT images for congenital anomalies of the left BCV including aberrant and supernumerary BCVs. The associated congenital aortic anomalies were assessed. RESULTS: Among 73,407 cases at a university hospital, 22 (16 males, 6 females; mean age, 59 years) with aberrant left BCVs were found using keyword research on recorded reports (0.03%). Among 8018 cases at the branch hospital, 5 (4 males, 1 female; mean age, 67 years) with aberrant left BCVs were found using CT image review (0.062%). There were no significant differences in incidences of aberrant left BCV between the two groups. Two cases had double left BCVs. Eleven cases showed high aortic arches. Two cases had the right aortic arch, one case had an incomplete double aortic arch, and one case was associated with coarctation. CONCLUSION: Aberrant left BCV on CT examination in adults was extremely rare. Some cases were associated with aortic arch anomalies.

The Apparent Diffusion Coefficient (ADC) as a Potential Marker of Inflammation Associated with Body Abscesses.

OBJECTIVE: To assess the feasibility of apparent diffusion coefficient analysis in evaluating the inflammatory severity of extracranial abscesses. METHODS: This retrospective study included 23 patients with solitary body abscesses (except those in the brain) who underwent 1.5-T diffusion-weighted magnetic resonance imaging (DWI) at b-values of 0 and 1000 s/mm2. Three types of the Apparent Diffusion Coefficient (ADC) measurements of abscesses were performed: the mean ADC value in region of interest (ROI), volume of interest (VOI), and histogram analysis of the ADC distribution in the VOI. Furthermore, two different areas were used: high-intensity area on b = 0 and b = 1000 s/mm2 images. Subsequently, correlations between ADC data and C-reactive protein (CRP) levels were assessed using Pearson's correlation coefficient (R) analyses. RESULTS: The strongest correlation was observed between the mean ADC value in VOI and CRP level (R = 0.78, P < 0.01), followed by ROI (R = 0.77, P < 0.01) by using the high-intensity area on the b = 0 s/mm2 images. CONCLUSION: The mean ADC value in the ROI encompassing the abscess at a b-value of 0 s/mm2 may be useful to assess the inflammatory activity of an abscess in daily practice.

Effects of chemoradiotherapy on lymph nodes in patients with rectal adenocarcinoma: evaluation of numbers and sizes of retrieved lymph nodes inside and outside the radiation field.

BACKGROUND: Preoperative chemoradiotherapy (CRT) decreases the number of retrieved lymph nodes (LNs) in rectal cancer. LNs inside the irradiation field are affected by CRT, whereas those outside the irradiation field are affected only by concurrent chemotherapy. PATIENTS AND METHODS: The study cohort comprised of 210 patients with clinical stage II/III rectal adenocarcinoma. One hundred and eight received surgery alone (S group), and 102 received preoperative CRT (40 or 45 Gy) with concurrent oral UFT or S-1 uracil/tegafur or S-1 (CRT group). RESULTS: The number of LNs inside the irradiation field was significantly smaller in the CRT group (4 ± 4) than in the S group (6 ± 6, p<0.01), but the number of LNs outside the irradiation field did not differ (5 ± 4 in both groups). The longest diameters of LNs in the S group were significantly smaller than those of the CRT group both inside and outside the irradiation fields (p<0.01). CONCLUSION: The effects of CRT on LNs in patients with rectal adenocarcinoma differed inside and outside the radiation field.

A case of right double inferior vena cava with circumcaval ureter.

Congenital inferior vena cava (IVC) anomalies are silent and detected incidentally on imaging. Double IVC is the most common IVC anomaly and is usually characterized by the presence of an IVC on each side of the abdominal aorta. In contrast, right double IVC, which is defined as two post-renal IVCs positioned to the right of the abdominal aorta, is seldom recognized. We report a rare case of a complete right double IVC with a circumcaval ureter that was incidentally detected by CT and describe the embryological and clinical implications.

Biopsy specimens obtained 7 days after starting chemoradiotherapy (CRT) provide reliable predictors of response to CRT for rectal cancer.

PURPOSE: Preoperative chemoradiation therapy (CRT) significantly decreases local recurrence in locally advanced rectal cancer. Various biomarkers in biopsy specimens obtained before CRT have been proposed as predictors of response. However, reliable biomarkers remain to be established. METHODS AND MATERIALS: The study group comprised 101 consecutive patients with locally advanced rectal cancer who received preoperative CRT with oral uracil/tegafur (UFT) or S-1. We evaluated histologic findings on hematoxylin and eosin (H&E) staining and immunohistochemical expressions of Ki67, p53, p21, and apoptosis in biopsy specimens obtained before CRT and 7 days after starting CRT. These findings were contrasted with the histologic response and the degree of tumor shrinkage. RESULTS: In biopsy specimens obtained before CRT, histologic marked regression according to the Japanese Classification of Colorectal Carcinoma (JCCC) criteria and the degree of tumor shrinkage on barium enema examination (BE) were significantly greater in patients with p21-positive tumors than in those with p21-negative tumors (P=.04 and P<.01, respectively). In biopsy specimens obtained 7 days after starting CRT, pathologic complete response, histologic marked regression according to both the tumor regression criteria and JCCC criteria, and T downstaging were significantly greater in patients with apoptosis-positive and p21-positive tumors than in those with apoptosis-negative (P<.01, P=.02, P=.01, and P<.01, respectively) or p21-negative tumors (P=.03, P<.01, P<.01, and P=.02, respectively). The degree of tumor shrinkage on both BE as well as MRI was significantly greater in patients with apoptosis-positive and with p21-positive tumors than in those with apoptosis-negative or p21-negative tumors, respectively. Histologic changes in H&E-stained biopsy specimens 7 days after starting CRT significantly correlated with pathologic complete response and marked regression on both JCCC and tumor regression criteria, as well as with tumor shrinkage on BE and MRI (P<.01, P<.01, P<.01, P<.01, and P=.03, respectively). CONCLUSIONS: Immunohistochemical expressions of p21 and apoptosis together with histologic changes on H&E-stained biopsy specimens obtained 7 days after starting CRT are strong predictors of the response to CRT.

Anomalous inferior vena cava associated with horseshoe kidney on multidetector computed tomography.

We evaluated the prevalence of anomalous inferior vena cava (IVC) associated with 205 patients with horseshoe kidney (HSK) and 1990 patients without HSK on multidetector computed tomography and compared prevalence between both groups. We identified anatomical variations of the IVC in 8 patients (3.9%) with HSK (1 preisthmic IVC with retrocaval ureter, 4 double IVCs, 2 left IVCs, and 1 IVC with azygos continuation) and in 12 patients (0.6%) without HSK (8 double IVCs, 3 left IVCs, and 1 IVC with azygos continuation). Anomalous IVC was significantly more frequent in patients with HSK than those without it.

Assessment of renal shape of horseshoe kidney with multidetector row CT in adult patients: relationship between urolithiasis and renal isthmus.

OBJECTIVE: The aim of this study was to evaluate the relationship between urolithiasis and characteristics of renal shape in adult patients with horseshoe kidney (HSK) diagnosed on multidetector row computed tomography (MDCT). METHODS: We evaluated 36 patients with HSK and urolithiasis (Group A) and 70 patients with HSK without urolithiasis (Group B) whose disease was diagnosed on non-contrast MDCT. Two radiologists measured minimum width of the renal isthmus and maximum length of the renal pelvis and evaluated coexisting neoplastic diseases on axial computed tomographic (CT) images with 5-mm reconstruction, and we compared those measurements between the Groups A and B. RESULTS: The overall mean maximum length of the renal pelvis, 12.7±9.2 mm, did not differ significantly between the 2 groups. Minimum isthmus width was larger in patients with HSK and urolithiasis (11.0±5.6 mm), than those without urolithiasis (9.5±5.1 mm). No patient in either groups had a urological renal tumor. CONCLUSIONS: Patients of HSK might have tendency of a high incidence of stone formation. Because urolithiasis is a risk factor for tumors of the renal pelvis, monitoring of patients with HSK requires careful attention to isthmus width on CT images.

Initial experience with computed tomographic colonography applied for noncolorectal cancerous conditions.

PURPOSE: The aim of this study was to asses retrospectively the performance of computed tomography colonography (CTC) for noncolorectal cancerous conditions. MATERIAL AND METHODS: A total of 44 patients with non-colorectal cancerous conditions underwent CTC. We researched the indications for CTC or present illness and evaluated the CTC imaging findings. We assessed whether diagnosis by CTC reduced conventional colonoscopic examinations. RESULTS: A total of 47 examinations were performed in 44 patients. The indications for CTC or a present illness were as follows: 15 patients with impossible or incomplete colonoscopy, 7 with diverticular disease, 6 with malignancy (noncolorectal cancer), 6 with Crohn's disease, 4 suspected to have a submucosal tumor on colonoscopy, 2 with ischemic colitis, and 4 with various other diseases. Colonic findings were diagnosed on CTC in 36 examinations, and extracolonic findings were identified in 35 of 44 patients. In all, 17 patients had undergone colonoscopy previously, 9 (52.9%) of whom did not require further colonoscopy by CTC. Five patients underwent colonoscopy after CTC. CONCLUSION: The indications for CTC were varied for patients with noncolorectal cancerous conditions. CTC examinations could be performed safely. Unlike colonoscopy or CT without preparation, CTC revealed colonic and extracolonic findings and may reduce the indication of colonoscopy in patients with noncolorectal cancerous conditions.