T2 hypointense signal discovered incidentally at the posterior edge of the adenohypophysis on MRI: its prevalence and morphology and their relationship to age.

PURPOSE: T2 hypointense signal at the posterior edge of the adenohypophysis (T2HSPA) on magnetic resonance imaging (MRI) is incidentally encountered. We aimed to investigate the prevalence and morphology of T2HSPA and their relationship to age. METHODS: A total of 212 cases between 3 and 88 years old were examined. Sagittal T2-weighted image (T2WI) was evaluated for the presence of T2HSPA, which classified by its morphology into two types (belt-like or nodal). The Wilcoxon rank sum test and chi-square test were used to evaluate the differences between the groups. The T2HSPA was extracted by ImageJ software and measured as a cross-sectional area (CSA) quantitatively by threshold setting. We examined the relationship between CSA of T2HSPA and age, and Spearman's correlation coefficients were used for statistical analysis. RESULTS: Of the 212 cases, 80 (37.7%) were identified with T2HSPA. The groups with T2HSPA were significantly younger than the groups without it (p = .01). Groups with belt-like T2HSPA were significantly younger than the groups with nodal T2HSPA (p = .01). There was a weak negative correlation between CSA of T2HSPA and age (p = .02). CONCLUSION: T2HSPAs were incidentally detected in 37.7% of all cases, tended to be more common in younger cases, and their morphology was related to age. They seem to have little clinical significance as they tend to decrease in size with age.

The value of CT findings for prognostic prediction of spontaneous superior mesenteric artery dissection.

BACKGROUND: Spontaneous superior mesenteric artery (SMA) dissection is rare cause of acute abdomen. Time-dependent change of SMA dissection has not been established. PURPOSE: To determine Sakamoto classification (SC) type of acute and chronic SMA dissection (aSMAD and cSMAD) to predict the treatment methods and outcome. MATERIAL AND METHODS: From April 2003 to March 2017, unenhanced and contrast-enhanced CT were used to diagnose acute symptomatic or chronic asymptomatic SMA dissection in 25 consecutive patients without aortic dissection. Correlations between SCs and treatment methods and outcomes were investigated. RESULTS: All 13 patients with aSMAD initially received conservative treatment. Initial SCs in aSMAD were type I = 1, type III = 9, and type IV = 3. Three of nine initial type III and two of three initial type IV changed to type I at follow-up. One of nine type III changed to type II at follow-up. Ohers did not change. One with initial type III required vascular repair, so the final SC was not available. Three patients required bowel resection. In cSMAD of 12 patients, the initial/final SC were type I and IV in ten and two patients, respectively, without change during follow-up. cSMAD was significantly older than aSMAD. The initial length of dissection of aSMAD was longer than in the cSMAD group. In aSMAD, the final length of dissection was significantly shorter than in the initial computed tomography scan. CONCLUSION: Initial SC differed significantly between aSMAD and cSMAD. Initial SC types in aSMAD were type III and IV mainly, and changed during the observation period. In cSMAD, SC types were I and IV without change.

Comparison of utility of tumor size and apparent diffusion coefficient for differentiation of low- and high-grade clear-cell renal cell carcinoma.

BACKGROUND: There is a significant correlation between tumor size and tumor grade for clear-cell renal cell carcinoma (RCC) in pathology. Thus, apparent diffusion coefficient (ADC) of clear-cell RCC might be influenced by tumor size. PURPOSE: To compare the utility of tumor size and ADC for distinguishing low-grade from high-grade clear-cell RCC. MATERIAL AND METHODS: Forty-nine patients undergoing preoperative magnetic resonance imaging were retrospectively assessed. ADC values were calculated using b-value combinations of 0 and 800 s/mm(2) at 1.5 T. Two radiologists in consensus measured ADC values via small region of interest (ROI) (mean ROI area, 88.8 mm(2); range, 80-108 mm(2)) placement on an area of solid tumor on a single slice. Maximum tumor diameter was measured at the maximum tumor area. A single pathologist reviewed all pathological slides to determine the nuclear grade according to the Fuhrman classification. The utility of ADC, tumor size, and ADC/size ratio for distinguishing low-grade from high-grade tumors was assessed. Receiver-operating characteristic (ROC) analysis and regression analysis of the each index were performed. The correlation between ADC and tumor size was also investigated. RESULTS: The 49 clear-cell RCC included 34 low-grade and 15 high-grade tumors. The differences of ADC, tumor size, and ADC/size ratio between high-grade and low-grade tumors were statistically significant (P <0.05). The area under the ROC curve of ADC, tumor size, and ADC/size ratio were 0.802, 0.763, and 0.804 respectively. However, using regression analysis, only ADC (P <0.05) was statistically significant index as independent risk factors for high-grade clear-cell RCC. Moreover, weak significant correlation was observed between tumor size and ADC (R(2) = 0.3865, P <0.01). CONCLUSION: There was a weak significant correlation between tumor size and ADC value of clear-cell RCC. Using ROC and regression analysis, ADC was statistically significant index for distinguishing low-grade from high-grade clear-cell RCC more than tumor size and ADC/size ratio.

Short treatment time and excellent treatment outcome in accelerated hyperfractionated radiotherapy for T1 glottic cancer.

Accelerated hyperfractionated radiotherapy was performed as treatment for patients with T1 glottic cancer, and its utility was evaluated based on treatment outcomes and adverse effects. Fifty-eight men who had undergone radiotherapy were retrospectively reviewed. Tumor classification was Tis in 4 patients, T1a in 38, and T1b in 16. Histological examination revealed squamous cell carcinoma in 55 patients. Travel time from home to hospital was 0-1 hour for 24 patients, 1-2 hours for 9, and >2 hours for 25. Laser vaporization was performed prior to radiotherapy in 38 patients, and 19 patients received concurrent chemotherapy with an agent such as S-1. Patients were irradiated twice daily using an irradiation container. Most patients received a dose of 1.5 Gy/fraction up to a total of 60 Gy. The median overall treatment time was 30 days, with a median observation period of 59.6 months. A complete response was observed in all patients. The 5-year overall survival, disease-free survival, and local control rates were 97.2%, 93.2%, and 97.8%, respectively. Although grade 3 pharyngeal mucositis was observed in 2 patients, there were no other grade 3 or higher acute adverse events. As late toxicity, grade 2 laryngeal edema and grade 1 laryngeal hemorrhage were observed in 1 patient each, but no serious events such as laryngeal necrosis or laryngeal stenosis were observed. In conclusion, this treatment method brings excellent outcome and will substantially reduce the treatment duration among patients who need to stay at nearby hotels while undergoing treatment at hospitals in rural areas.

Acute abdomen by red degeneration of a parasitic leiomyoma: A case report and literature review.

A 43-year-old woman, with a history of uterine fibroids and multiple myomectomy, presented with acute lower abdominal pain. Computed tomography revealed multiple tumors, including a high-density mass in the left lower abdomen indicative of a parasitic leiomyoma undergoing red degeneration. This uncommon condition is due to acute occlusion, often caused by peripheral venous thrombosis at the fibroid edge. The diagnosis was corroborated by distinctive findings on magnetic resonance imaging and computed tomography. Notably, high signal intensity on T1-weighted images (T1WI) suggested methemoglobin presence due to hemorrhagic infarction, whereas low signal intensity on T2-weighted images (T2WI) indicated deoxyhemoglobin. Symptom improvement followed treatment with analgesics. This case underscores the significance of considering parasitic myomas in the differential diagnosis of intraperitoneal tumors after myomectomy and proposes that vascular torsion from mechanical stress on the mobile mesentery may contribute to red degeneration in such tumors. In this report, we detail the imaging characteristics and clinical progression of red degeneration in a parasitic leiomyoma, emphasizing the importance of this diagnosis in patients with a history of uterine surgery.

A case of gallbladder abscess caused by torsion that completely disappeared following drainage.

A woman in her 90s presented with loss of appetite, lower back pain, abdominal pain, and fever. Physical examination and subsequent blood tests indicated an inflammatory process, and computed tomography (CT) scans revealed gallbladder torsion with necrosis and abscess formation. The case involved successful management of this rare condition through percutaneous drainage without the need for surgical intervention, avoiding complications during follow-up. Remarkably, post-treatment CT showed complete resolution of the gallbladder abscess and the gallbladder itself was no longer visible. This case highlights the effectiveness of minimally invasive treatment for gallbladder torsion in elderly patients and underscores the potential for non-surgical intervention in managing complex abdominal conditions.

Evaluation of Local Vascular Perfusion in the Lower Extremities on Intravoxel Incoherent Motion Imaging before and after Endovascular Therapy.

PURPOSE: To evaluate improvement in local vascular perfusion of the lower limbs on intravoxel incoherent motion (IVIM) imaging after endovascular therapy (EVT). MATERIALS AND METHODS: IVIM imaging was performed on 20 lower limbs of 16 patients with lower extremity arterial diseases before and after EVT. To estimate IVIM, diffusion-weighted lower-limb axial images (number of slices = 25 and slice thickness = 3.5 mm) were acquired using different b values (0, 300, and 1000 s/mm2). IVIM imaging with the simplified IVIM techniques was performed. The perfusion-related coefficient (D* [10-3 mm2/s]), perfusion fraction (f [%]), and D*f product (10-3 mm2/s %) were calculated before and 2-3 days after EVT. The ankle brachial index (ABI), mean D* (10-3 mm2/s), mean f (%), and mean D*f product (10-3 mm2/s %) before and after EVT were compared. RESULTS: Successful revascularization was achieved in all cases. After EVT, the mean ABI significantly increased from 0.59 ± 0.19 to 0.87 ± 0.15 (p < 0.001, paired t test). The mean D* (10-3 mm2/s) (22.08 ± 3.26 versus 24.87 ± 2.65, p = 0.005, paired t test), and D*f product (10-3 mm2/s%) (551.03 ± 79.02 versus 634.55 ± 76.96, p = 0.002, paired t-test) of the lower limbs significantly increased after EVT, whereas f (%) (25.00 ± 1.28 versus 25.52 ± 1.61, p = 0.261, paired t-test) did not significantly increased after EVT. CONCLUSION: D* (10-3 mm2/s) and D*f product (10-3 mm2/s %) on IVIM imaging could evaluate improvement in local vascular perfusion of the lower limbs after EVT. LEVEL OF EVIDENCE: Level 4, Case Series.

Exploration of tumor size measurement methods in preoperative breast cancer assessment using whole-body silicon photomultiplier PET: feasibility and first results.

PURPOSE: Whole-body silicon photomultiplier positron emission tomography (WB SiPM PET) could be used to diagnose breast cancer spread before lumpectomy. We aimed to investigate the method of measuring the tumor size by WB SiPM PET as a basis for diagnosing breast cancer spread in the breast. MATERIALS AND METHODS: We retrospectively reviewed 35 breast cancer lesions in 32 patients who underwent WB SiPM PET/CT in the prone position as preoperative breast cancer examinations from September 2020 to March 2022. In all cases, a 20-mm spherical VOI was placed in the normal mammary gland to measure the mean standardised uptake value (SUVmean) and the standard deviation (SD) of 18F-fluorodeoxyglucose (FDG) uptake. We prepared four types of candidates (SUVmean + 2 SD, SUVmean + 3 SD, 1.5 SUVmean + 2 SD, 1.5 SUVmean + 3 SD) for thresholds for delineating tumor contours on PET images. On the semiautomatic viewer soft, the maximum tumor sizes were measured at each of the four thresholds and compared with the pathological tumor sizes, including the extensive intraductal component (EIC). RESULTS: The lesion detection sensitivity was 97% for WB SiPM PET. PET detected 34 lesions, excluding 4-mm ductal carcinomas in situ (DCIS). PET measurements at the '1.5 SUVmean + 2 SD' threshold demonstrated values closest to the pathological tumor sizes, including EIC. Moreover, '1.5 SUVmean + 2 SD' had the highest concordance (63%). CONCLUSIONS: The study demonstrated that among various PET thresholds, the '1.5 SUVmean + 2 SD' threshold exhibited the best performance. However, even with this threshold, the concordance rate was limited to only 63%.

Three-dimensional velocity vector image obtained via 4-dimensional flow magnetic resonance imaging for in-stent flow visualization in the superficial femoral artery.

The assessment of stent lumen patency via non-contrast-enhanced 2-dimensional time-of-flight magnetic resonance angiography (2D TOF MRA) is complex due to stent-related artifacts. However, an imaging technique using the phase-contrast method, which can reduce susceptibility to artifact, is available. Herein, we report the use of 3-dimensional velocity vector image obtained via 4-dimensional flow magnetic resonance imaging (4D flow MRI) for in-stent flow visualization after stent development in the right superficial femoral artery. Hence, instead of 2D TOF MRA, 4D flow MRI using the phase-contrast method can be performed to assess stent lumen patency as it reduces stent-related artifacts.

Radiological Features of T1a Renal Cell Carcinoma on Axial Unenhanced Computed Tomography.

CT has become a commonly used diagnostic procedure in clinical practice, particularly in emergency healthcare delivery. Accordingly, the increase in CT usage has increased the likelihood of incidental detections (ID) of renal cell carcinomas (RCCs). This article discusses key points and limitations associated with the diagnosis and characterization of T1a RCC (≤4 cm in diameter) and shows how to improvise on the differentiation of T1a RCC with unenhanced CT (UE-CT). We retrospectively reviewed UE-CT findings of cases associated with the histopathologic diagnosis of T1a RCC and examined the discrimination capacity and radiological characteristics with regard to small RCCs (SRCCs). Detection and characterization of T1a RCC based on UE-CT are not easy in many cases due to limitations in CT findings, but there are notable radiological features to facilitate detection and differentiation. The growth pattern is important for the detection of SRCCs. Internal characteristic features (average attenuation, heterogeneity) are useful for the characterization of the RCC. In addition, CT image visualization techniques may help improve the detectability of RCCs on UE-CT. Radiological features are important in detecting SRCCs and facilitating further examination. In this study, we discuss some cases of T1a RCCs and evaluate the radiological characteristics of the tumors seen on UE-CT.

Massive spontaneous nontraumatic subcapsular hepatic hematoma treated using arterial embolization: A case report and review of the literature.

A nontraumatic and idiopathic spontaneous subcapsular hepatic hematoma is a rare but often fatal condition. Herein, we report a case of nontraumatic progressive massive subcapsular hepatic hematoma that straddled both liver lobes and was successfully treated by repeated arterial embolization. Following treatment, the hematoma did not progress.

A case of breast cancer: Suppression of lactation-related FDG uptake 2 days after cabergoline administration.

We present a case of a 35-year-old woman with breast cancer in lactation 3 months after childbirth, in which a lactation inhibitor was useful for 18F-FDG PET/CT examination. Via ultrasonography and biopsy with histopathology, we diagnosed the lesion in the upper region of the left breast as invasive ductal carcinoma. She stopped breastfeeding and was administered cabergoline to suppress lactation. Two days after the administration, 18F-FDG PET/CT revealed segmental uptake (10 cm in diameter) and no lactation-related uptakes. Dynamic MRI also revealed a segmental enhancement of the same size as 18F-FDG PET/CT. The lactation inhibitor was useful to delineate the extent of the lesion during the 18F-FDG PET/CT examination.

Steerable-wire technique using high-flow steerable microcatheter and 0.025-inch guidewire.

A high-flow steerable microcatheter has been reported to be useful as a triaxial system. Moreover, the benefits of steerable microcatheters in acute-angle bifurcation vessel insertions and a compact coil-packing technique using intentional folding with a bendable catheter tip have been reported. However, research on the usefulness of a high-flow steerable catheter and 0.025-inch guidewire combination (steerable-wire) technique is lacking. Herein, we report a case of balloon-occluded retrograde transvenous obliteration (BRTO) via the femoral venous approach to illustrate the usefulness of the steerable-wire technique. The steerable-wire technique facilitates the selection of the wire into the target vessel. The steerable-wire can be used instead of the 0.035-inch guidewire, which is versatile as other devices can follow the steerable wire.

Pseudohemothorax induced by residual contrast medium mimicking aortic dissection rupture.

Hemothorax is an urgent condition, and its accurate diagnosis and the identification of the cause are important. Herein, we report a case of a 74-year-old man with end-stage renal disease who was presented with high-concentration pleural effusion owing to residual contrast medium. The case required differentiation from hemothorax owing to an aortic dissection and its rupture. In patients with end-stage renal disease, noncontrast-enhanced computed tomography after contrast-enhanced computed tomography may result in high-concentration pleural effusion owing to the existence of residual contrast medium. This realization is important to determine whether high-concentration pleural effusion symptoms reflect an urgent hemothorax case possibly related to an imminent rupture of an aortic aneurysm or intrathoracic penetration of aortic dissection, and whether invasive procedures, such as thoracentesis, ought to be avoided.

Clinicoradiological Characteristics of Gastric Metastases: A Single Center Retrospective Study.

BACKGROUND:  With recent advances in treatment, gastric metastases are increasingly becoming the subject of diagnostic imaging. On the other hand, it is difficult to detect gastric metastasis on CT finding images. PURPOSE:  To characterize the CT findings of gastric metastasis and investigate its treatment method and natural history in patients. MATERIALS AND METHODS:  We retrospectively reviewed the CT findings of 15 patients diagnosed with gastric metastasis between April 2003 and December 2019 in our hospital. The location, size, and shape of the tumors on CT were evaluated. Moreover, their medical records, characteristics, complications, treatment options, and natural course were evaluated. RESULTS:  Of the 15 patients with gastric metastasis, 9 were male and 6 were female. The median age was 74 (55-87) years. Gastric metastasis was diagnosed simultaneously with primary cancer in five patients. In other patients, the median interval time from the date of primary cancer diagnosis to gastric metastasis diagnosis was 27 (10-259) months. CT findings revealed that the gastric metastasis had a median size of 18 (12-135) mm and was mainly located in the middle third of the stomach. In addition, most patients had a submucosal tumor (SMT) pattern, followed by diffuse wall thickness and polypoid patterns (11 [73.3%], 3 [20.0%], and 1 [6.7%], respectively). The median time to death after gastric metastasis diagnosis was 112 (17-883) days. CONCLUSION:  The SMT pattern in the middle third of the stomach is the characteristic CT finding of gastric metastasis.

Inverted intercostal hernia of elastofibroma dorsi mimicking well-differentiated liposarcoma in the chest wall.

Elastofibroma dorsi is a well-known benign chest wall tumor. Herein, we present a case in which an elastofibroma protruded into the thoracic cavity, leading to inverted intercostal hernia. Imaging revealed a soft tissue mass containing fat, typical of elastofibroma dorsi; however, precise diagnosis was difficult owing to the location of this mass that protruded into the thoracic cavity. Liposarcoma had to be ruled out because it was a growing fat-containing mass. Considering that the tumor moved while the patient was undergoing computed tomography-guided biopsy in the prone position, a diagnosis of inverted intercostal hernia of elastofibroma dorsi was made. We report this case with a review of current literature.

Increased future liver function after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy.

Background: The increasing ratio of functional future liver remnant (functional %FLR) after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy (modified-ALPPS) compared with portal vein embolization (PVE) has not been comprehensively evaluated. Purpose: To compare the increasing ratio of functional %FLR between modified-ALPPS and PVE via technetium-99 m-galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT/CT) fusion imaging. Material and Methods: Seven and six patients underwent modified-ALPPS (modified-ALPPS group) and PVE (PVE group) from 2015 to 2019. The functional %FLR on 99 mTc-GSA SPECT/CT fusion imaging was assessed before and 1 week (modified-ALPPS group) and 3 weeks (PVE group) after each procedure. The increasing ratio of functional %FLR (functional %FLR ratio) was calculated and compared between the two groups. Moreover, the hypertrophy ratio of future liver remnant volume (FLRV ratio) and atrophy ratio of embolized liver volume (.ELV ratio) were evaluated. Results: The mean functional %FLR ratios of the modified-ALPPS group (1.47 ± 0.15) and the PVE group (1.49 ± 0.20) were comparable (p > .05). The median FLRV ratio of modified-ALPPS group (1.48) was higher than that of the PVE group (1.16), the median ELV ratio of the PVE group (0.81) was lower than that of the modified-ALPPS group (0.94), and the results significantly differed between the two groups (p < .05). Conclusion: The increasing ratio of functional %FLR was comparable between modified-ALPPS and PVE. Compared with PVE, ALPPS was associated with a higher hypertrophy rate of the remnant liver but a lower atrophy rate of the embolized liver.

Improvement in local vascular perfusion of the lower extremities on intravoxel incoherent motion imaging: A case report.

Intravoxel incoherent motion imaging has its improvement-evaluating ability in lower limb perfusion after endovascular therapy in individuals with lower extremity arterial disease. Here, we present a 70-year-old man with intermittent claudication of the left lower limb, whose microperfusion on intravoxel incoherent motion imaging improved after endovascular therapy. The patient underwent intravoxel incoherent motion imaging of the lower extremities pre- and postendovascular therapy. After endovascular therapy, the left ankle brachial index increased from 0.46 to 1.06. The mean perfusion-related coefficient (10-3 mm2/s) of the left lower limb increased from 19.70 ± 3.17 to 24.81 ± 3.41, and mean perfusion fraction (%) of the left lower limb slightly increased from 24.41 ± 0.96% to 25.20 ± 1.89% after endovascular therapy. Therefore, successful revascularization can improve microperfusion on intravoxel incoherent motion imaging in a patient with lower extremity arterial disease.

Low b-value diffusion-weighted imaging for diagnosing strangulated small bowel obstruction: a feasibility study.

PURPOSE: To assess the feasibility of low b-value diffusion-weighted imaging (DWI) for diagnosing strangulated small bowel obstruction (SBO). MATERIALS AND METHODS: Five volunteers and 14 patients with SBO underwent DWI at b-values of 0 and 50 s/mm(2). Apparent diffusion coefficients (ADCs) and signal preservation ratios (SPRs) were measured in the distal jejunum in the volunteers before and after butylscopolamine administration, and in the (strangulated) closed loop, near the obstructive site, and far from the obstructive site in the patients. Low b-value diffusion-weighted images in the patients were quantitatively evaluated for diagnosing strangulation. RESULTS: In the volunteers, mean ADC (10(-3) mm(2)/s) and SPR (%) before butylscopolamine administration (18.3 ± 5.9 and 41.4 ± 11.5) were significantly different (P < 0.05) from those after butylscopolamine administration (6.4 ± 3.6 and 73.7 ± 12.9). In the patients, mean ADCs and SPRs among the strangulated closed loop (3.8 ± 2.2 and 83.3 ± 9.3), near the obstructive site (12.1 ± 6.9 and 57.3 ± 18.5), and far from the obstructive site (26.8 ± 10.7 and 29.9 ± 16.4) were significantly different (P < 0.05). Areas under the receiver operating characteristic curve for the diagnosis of strangulation varied between 0.937 and 1.000. CONCLUSION: Low b-value DWI is a feasible technique to distinguish the strangulated closed loop from nonstrangulated loops in SBO, and show promise for diagnosing strangulated SBO.