The human heart is a complex organ in which many complicated congenital defects may happen and some of them require surgical intervention. Due to the vast complexity of varied anatomical presentations, establishing an accurate and consistent nomenclature system is utmost important to facilitate effective communication among pediatric cardiologists, cardiothoracic surgeons and radiologists. The Van Praagh segmental approach to the complex congenital heart disease (CHD) was developed in the 1960s and has been used widely as the language for describing complex anatomy of CHD over the decades. It utilizes a systematic and sequential method to describe the cardiac segments and connections which in turn allows accurate, comprehensive and unambiguous description of CHD. It can also be applied to multiple imaging modalities such as echocardiogram, cardiac CT and MRI. The Van Praagh notation demonstrates a group of three letters, with each letter representative for a key embryologic region of cardiac anatomy: the atria, ventricles and great vessels. By using a 3-steps approach, we can evaluate complex CHD precisely and have no difficulties in communicating with other medial colleague. This pictorial essay revisits the logical steps of segmental approach, followed by a pictorial illustration of its application.

Purpose: For a single time-point hyperpolarized $^{13}C$ magnetic resonance spectroscopy imaging (MRSI) of animal models, scan-time window after injecting substrates is critical in terms of signal-to-noise ratio (SNR) of downstream metabolites. Pre-scans of time-resolved magnetic resonance spectroscopy (MRS) can be performed to determine the scan-time window. In this study, based on two-site exchange model, protocol-specific simulation approaches were developed for $^{13}C$ MRSI and the optimal scan-time window was determined to maximize the SNR of downstream metabolites. Materials and Methods: The arterial input function and conversion rate constant from injected substrates (pyruvate) to downstream metabolite (lactate) were precalibrated, based on pre-scans of time-resolved MRS. MRSI was simulated using two-site exchange model with considerations of scan parameters of MRSI. Optimal scan-time window for mapping lactate was chosen from simulated lactate intensity maps. The performance was validated by multiple in vivo experiments of BALB/C nude mice with MDA-MB-231 breast tumor cells. As a comparison, MRSI were performed with other scan-time windows simply chosen from the lactate signal intensities of pre-scan time-resolved MRS. Results: The optimal scan timing for our animal models was determined by simulation, and was found to be 15 s after injection of the pyruvate. Compared to the simple approach, we observed that the lactate peak signal to noise ratio (PSNR) was increased by 230%. Conclusion: Optimal scan timing to measure downstream metabolites using hyperpolarized $^{13}C$ MRSI can be determined by the proposed protocol-specific simulation approaches.

Purpose: To investigate whether volumetric analysis based on T2WI and contrast-enhanced (CE) T1WI can distinguish between isocitrate dehydrogenase-1 mutation-positive ($IDH1^P$) and -negative ($IDH1^N$) glioblastomas (GBMs). Materials and Methods: We retrospectively enrolled 109 patients with histopathologically proven GBMs after surgery or stereotactic biopsy and preoperative MR imaging. We measured the whole-tumor volume in each patient using a semiautomatic segmentation method based on both T2WI and CE T1WI. We compared the tumor volumes between $IDH1^P$ (n = 12) and $IDH1^N$ (n = 97) GBMs using an unpaired t-test. In addition, we performed receiver operating characteristic (ROC) analysis for the differentiation of $IDH1^P$ and $IDH1^N$ GBMs using the tumor volumes based on T2WI and CE T1WI. Results: The mean tumor volume based on T2WI was larger for $IDH1^P$ GBMs than $IDH1^N$ GBMs ($108.8{\pm}68.1$ and $59.3{\pm}37.3mm^3$, respectively, P = 0.0002). In addition, $IDH1^P$ GBMs had a larger tumor volume on CE T1WI than did $IDH1^N$ tumors ($49.00{\pm}40.14$ and $22.53{\pm}17.51mm^3$, respectively, P < 0.0001). ROC analysis revealed that the tumor volume based on T2WI could distinguish $IDH1^P$ from $IDH1^N$ with a cutoff value of 90.25 (P < 0.05): 7 of 12 $IDH1^P$ (58.3%) and 79 of 97 $IDH1^N$ (81.4%). Conclusion: Volumetric analysis of T2WI and CE T1WI could enable $IDH1^P$ GBMs to be distinguished from $IDH1^N$ GBMs. We assumed that secondary GBMs with $IDH1^P$ underwent stepwise progression and were more infiltrative than those with $IDH1^N$, which might have resulted in the differences in tumor volume.

Purpose: To determine whether we should recommend ultrasonography (US) for an incidental thyroid nodule identified by additional cervicothoracic sagittal T2-weighted image (C-T sag T2WI) of lumbar spine magnetic resonance imaging (MRI). Materials and Methods: A retrospective study of 61 patients who underwent both lumbar spine MRI and thyroid US between December 2011 and April 2015 was conducted. For all US-found thyroid nodules > 1 cm, investigators evaluated whether there was any correlation between thyroid nodule detectability by C-T sag T2WI and US features such as echogenicity, composition, or suspicion of malignancy. Results: Solid hypoechoic (2/4; 50%) or mixed echoic nodules (4/8; 50%) appeared to be found relatively more easily by C-T sag T2WI than more benign-looking solid isoechoic (1/4; 25%) or spongiform nodules (0/6; 0%). Among six nodules with ultrasonographic suspicion for malignancy, only one nodule was detected by C-T sag T2WI. Conclusion: If an incidental thyroid nodule is seen by C-T sag T2WI, it would be better to recommend thyroid US for identifying malignancy.

A 17-year-old girl presented with complaints of headache and decreasing vision of one month's duration, without any history of fever, weight loss, or any evidence of an immuno-compromised state. Her neurological examination was normal, except for papilledema. Laboratory investigations were within normal limits, except for a slightly increased Erythrocyte Sedimentation Rate (ESR). Non-contrast computerized tomography of her head revealed complex mass in left frontal lobe with a concentric, slightly hyperdense, thickened wall, and moderate perilesional edema with mass effect. Differential diagnoses considered in this case were pilocytic astrocytoma, metastasis and abscess. Magnetic resonance imaging (MRI) obtained in 3.0 Tesla (3.0T) scanner revealed a lobulated outline cystic mass in the left frontal lobe with two concentric layers of T2 hypointense wall, with T2 hyperintensity between the concentric ring. Moderate perilesional edema and mass effect were seen. Post gadolinium study showed a markedly enhancing irregular wall with some enhancing nodular solid component. No restricted diffusion was seen in this mass in diffusion weighted imaging (DWI). Magnetic resonance spectroscopy (MRS) showed increased lactate and lipid peaks in the central part of this mass, although some areas at the wall and perilesional T2 hyperintensity showed an increased choline peak without significant decrease in N-acetylaspartate (NAA) level. Arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC) enhanced perfusion study showed decrease in relative cerebral blood volume at this region. These features in MRI were suggestive of brain abscess. The patient underwent craniotomy with excision of a grayish nodular lesion. Abundant acid fast bacilli (AFB) in acid fast staining, and epithelioid cell granulomas, caseation necrosis and Langhans giant cells in histopathology, were conclusive of tubercular abscess. Tubercular brain abscess is a rare manifestation that simulates malignancy and cause diagnostic dilemma. MRI along with MRS and magnetic resonance perfusion studies, are powerful tools to differentiate lesions in such equivocal cases.

Breast hamartomas are typically a benign condition and rarely develop into malignant lesions. The coexistence of carcinoma and a breast hamartoma is rare; only 15 cases have been reported in the literature. Here, we report a case of invasive ductal carcinoma associated with hamartoma in a 60-year-old woman. Mammography, ultrasonography and magnetic resonance imaging showed typical features of a breast hamartoma and a suspicious mass with microcalcifications arising within the hamartoma.

Arteriovenous malformation (AVM) of the pancreas is extremely rare, although it may be increasingly diagnosed due to the widespread use of cross-sectional imaging of the abdomen. Early diagnosis of this disease is important to prevent delay of treatment and resulting fatal complications. We report a rare case of pancreatic AVM in a 48-year-old man who presented with severe chronic anemia and early gastric cancer, which made diagnosis challenging. Imaging findings, including ultrasound, computed tomography, and magnetic resonance imaging, are shown, as well as the pathologic features.

Hemangioblastomas are angioblastic tumors of the central nervous system. Cerebellar hemangioblastomas are traditionally classified into two morphologic types-cystic and solid. Cystic hemangioblastomas are associated with peritumoral edema, but solid hemangioblastomas are not. We report a case of solid cerebellar hemangioblastoma with massive peritumoral edema. An 83-year-old female visited our hospital due to a sudden headache. Five years ago, she had been admitted to our hospital with similar headache and diagnosed with cerebellar hemangioblastoma. Follow-up brain MRI 5 years later showed an increased size of a homogeneous enhancing mass with aggravated peritumoral edema in the left lower cerebellar hemisphere. Cerebral angiography showed a highly vascularized mass in the cerebellum, which was compatible with a solid-type hemangioblastoma.

Intracranial involvement in multiple myeloma patients takes up around 1%, and is usually known to be present in the parietal bone or skull base in cases of skull vault involvement, while it presents in the dura and parenchyma in cases of intracranial involvement. Primary pachymeningeal invasion is even rarer with extremely rapid progression and very poor prognosis. It is our intent to report a case in which we had to differentiate multiple myeloma with other metastatic tumors, lymphoma, and leukemia with intracranial involvement. Our patient showed an osteolytic lesion of the skull with dural involvement and subdural mass formations.